Faculty Profiles - FUJIWARA Takeshi

Papers - FUJIWARA Takeshi

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The perception of plastic waste and composition of boathouse waste in floating villages on Tonlé Sap Lake, Cambodia Invited Reviewed

Mongolian Habuer, Takeshi Fujiwara, Spoann Vin, Phat Chandara, Makoto Tsukiji

Clean Technologies and Environmental Policy 2024.12

Optimizing cell phone recycling process: Unraveling rational and emotional drivers of consumer recycling participation using PLS-SEM and fs-QCA Reviewed

Yuxin Du, Habuer, Takeshi Fujiwara

Process Safety and Environmental Protection 191 218 - 233 2024.11

生ごみ分別回収済の可燃ごみを炭化処理することによる温室効果ガスの排出削減効果

遠入野生, 藤原健史

EICA 29 ( 2/3 ) 2024.10

Understanding driving forces of food waste separation intention to enhance regional and local solid waste planning: application of PLS-SEM and multi-group analysis Reviewed

Cuong Le Dinh, Takeshi Fujiwara, Song Toan Pham Phu, Habuer

Environmental Science and Pollution Research 31 ( 38 ) 50654 - 50669 2024.8

Authorship：Last author Language：English Publishing type：Research paper (scientific journal) Publisher：Springer Science and Business Media LLC

Abstract

This study extended the theory of planned behaviour (TPB) and applied it to analyse influencing factors of food waste separation intention (FSI) among households in central Vietnam. Partial least squares structural equation modelling (PLS-SEM) was employed to analyse the data. The heterogeneity of factors contributing to FSI in cities of three levels was examined using multi-group analysis (MGA). The results indicate that attitudes, subjective norms (SN), perceived behavioural control (PBC), awareness of benefit (AB), information publicity (IP), facility availability (FA), and trust significantly affected FSI of households. MGA results indicated the heterogeneity of impacts of PBC and attitude on FSI of households among three municipal levels. The results will serve as basic data for waste officers, solid-waste management project leaders, non-governmental organisations (NGOs), and other related stakeholders to lay the foundation of food waste management planning in terms of regional scale and local scale. This study will also aid the creation of a circular economy by providing a scientific base for enhancing food waste separation at source in central Vietnam.

DOI： 10.1007/s11356-024-34485-2

Other Link： https://link.springer.com/article/10.1007/s11356-024-34485-2/fulltext.html

脱炭素化に向けた廃棄物由来バイオガスのごみ収集への有効利用に関する研究 Reviewed

山下温大, 宗村健太, 藤原健史, 哈布尓

環境システム計測制御学会(EICA) 2023.10

Application of an Integrated Granular and Suspended Sludge Methane Reactor for a Two-Stage Anaerobic Digestion System to Deal with Biodegradable Municipal Solid Waste Reviewed

Pham Van Dinh, Takeshi Fujiwara

Fermentation 9 ( 8 ) 1 - 12 2023.8

Authorship：Last author Language：English Publishing type：Research paper (scientific journal)

This study aims to investigate the performance of a two-stage anaerobic digestion system using a hybrid methane reactor to deal with biodegradable municipal solid waste. The reactor allowed both suspended sludge and granular sludge to work together. The feedstock was fermented in one continuous stirred tank at different pH conditions for 5 d. Furthermore, the liquid hydrolysate was diluted and pumped into a methane reactor with different organic loading rates. In the fermentative reactor, raising the pH condition from 4.5 to 6.5 caused a sharp increase in volatile fatty acids concentration, mainly due to the increase in acetate and propionate. The efficiency of the methane reactor was proven by the results of hydrodynamic analysis and biogas production. The relationship between biogas production and operating parameters in this reactor was modeled using a quadratic multivariate regression model. Overall, by maintaining the fermentative reactor at a pH of 6.0–6.5, the methane reactor was able to achieve an organic loading rate of 7.6 g-TS.L−1·d−1 with outstanding biogas quality and yield. In terms of microbiology, the most dominant phyla in the reactor included Firmicutes, Bacteroidetes, Proteobacteria, Euryarchaeota, Synergistetes, and Chloroflexi. Among them, the species with the highest relative abundance in granular sludge was Firmicutes, while that in suspended sludge was Bacteroidetes.

DOI： 10.3390/fermentation9080720

Biogas Production and Energy Balance in a Two-Stage Anaerobic Digestion of Fruit and Vegetable Waste: Thermophilic versus Mesophilic Reviewed

Pham Van Dinh, Takeshi Fujiwara

Fermentation 9 ( 7 ) 1 - 11 2023.7

Authorship：Last author Language：English Publishing type：Research paper (scientific journal)

This study aimed to investigate biogas production and energy balance in a two-stage anaerobic digestion system of fruit/vegetable waste under thermophilic and mesophilic conditions. Firstly, the feedstock was hydrolyzed and acidified in an acidic reactor at 37 °C with a retention time of 5 d. Then, the liquid hydrolysate was collected and pumped into an up-flow methane reactor under a mesophilic temperature with a retention time of 5 d and a thermophilic condition with a retention time of 3 d. The experimental results showed that in the thermophilic methane reactor, the COD removal, biogas yield, and methane concentration were 96.3%, 492 mL/g-VS, and 70.4%, respectively. These values were 3%, 10%, and 3% higher, respectively, than those obtained in the mesophilic methane reactor. In terms of energy, the mesophilic and thermophilic methane reactors consumed the same thermal energy demand for temperature control. They were much lower than the heat values produced by the power engine. The two-stage anaerobic digestion system using a thermophilic methane reactor obtained a gross energy of 11.20 kJ/g-VS and a net energy of 9.83 kJ/g-VS. These values were 13.2% and 14.8% higher, respectively, than those obtained by the system with a mesophilic condition. Moreover, the use of a thermophilic reactor helped reduce the reactor volume by 40%, leading to significant investment cost savings.

DOI： 10.3390/fermentation9070601

Composting Activities in Vietnam – The Situation, Problems, and Challenges Reviewed

Duy Bao Nguyen, Takeshi Fujiwara, Cuong Le Dinh, Song Toan, Pham Phu

Chemical Engineering Transactions ( 106 ) 613 - 618 2023

An Analysis of Biodegradable Solid Waste Flow in Vietnam Reviewed

Cuong Le Dinh, Takeshi Fujiwara, Song Toan, Pham Phu

Chemical Transactions ( 106 ) 619 - 624 2023

Effects of effluent recirculation on two-stage anaerobic digestion in treatment of biodegradable municipal solid waste Reviewed

P. V. Dinh, T. Fujiwara, A. N. Peni, C. K. Tran

Global Journal of Environmental Science and Management 9 ( SI ) 35 - 46 2023

Language：English Publishing type：Research paper (scientific journal)

BACKGROUND AND OBJECTIVES: Advantages such as high stability and high biogas production when recirculating the effluent stream in two-stage anaerobic digestion systems have been demonstrated on a variety of substrates, but there is limited information regarding the use of this practice on organic municipal waste. Therefore, this study aimed to investigate how effluent recirculation affects the two-stage anaerobic digestion of biodegradable municipal solid waste. METHODS: Firstly, biodegradable municipal solid waste substrate was fermented under conditions of 12 percent initial total solids and a temperature of 36 degrees Celsius for 5 days. After that, the substrate continued to be diluted using tap water or the effluent stream with a rate of 2:1. In the case of using the effluent stream, the experiment was further performed with dilution rates of 3:1, 1:1, and 1:2. Then, the liquid part was collected and pumped into the methane reactor at an organic loading rate of 7.64 grams of total solids per liter per day at 36 degrees Celsius. The methane reactor was an up-flow reactor that contained both granular sludge and suspended sludge. The effectiveness of the experimental stages was evaluated through biogas production and chemical oxygen demand removal. FINDINGS: In the fermentative reactor, using the effluent stream to dilute solid-state feedstock helped keep the reactor stable at pH 5.5 without alkali addition. In the case of using tap water for dilution, it required a dose of 115.8 grams and 75.3 grams of sodium hydroxide per kilogram of volatile solids to attain pH conditions at 6.5 and 5.5, respectively. Maintaining the reactor at pH 6.5 increased the concentration of fermentation products compared to pH 5.5, including 5.9 percent total chemical oxygen demand, 5.5 percent soluble chemical oxygen demand, and 10.6 percent total volatile fatty acids. In the case of recirculating the effluent stream in the methane reactor, increasing the dilution rate from 0.5 to 3.0 resulted in a methane yield of 227.5-278.9 milliliter per gram of volatile solids and 85-93 percent chemical oxygen demand removal. The methane reactor’s best digestion performance was attained at recirculation rate 2. Methane formation mainly occurred in granular sludge via the hydrogenotrophic pathway. Methane formation in suspended sludge occurred in a secondary manner, mainly via both the hydrogenotrophic and acetotrophic pathways. Among methanogen families, Methanobacteriaceae was found to have the highest relative abundance (7.5 percent in granular sludge and 0.8 percent in suspended sludge). CONCLUSION: Recirculating the effluent provided significant benefits, including the ability to stabilize the hydrolysis process and increase the methane yield. A recirculation rate of 2 to obtain a total chemical oxygen demand of 35.2 grams per liter was the best condition for methanogenesis. Acetotrophic methanogens were better adapted to difficult conditions than hydrogenotrophic methanogens. The formation of methane mainly occurred in granular sludge via a dominant hydrogenotrophic pathway. Methane formation in suspended sludge occurred in a secondary manner, mainly via both the hydrogenotrophic and acetotrophic pathways. Among methanogen families, Methanobacteriaceae was found to have the highest relative abundance.

DOI： 10.22034/GJESM.2023.09.SI.03

A Perception Survey of Plastic Waste in Floating Villages on Tonle Sap Lake, Cambodia Reviewed

Habuer, Sakinah, binti Abdullah, Takeshi Fujiwara, Spoann Vin, Phat Chandara, Makoto Tsukiji

Chemical Engineering Transactions ( 106 ) 391 - 396 2023

Reduction of Carbon Dioxide Emissions during Garbage Collection using Biogas: Evaluation of Natural Gas Trucks and Electric Trucks Reviewed

Haruto Yamashita, Kenta Munemura, Takeshi Fujiwara, Habuer

EICA 28 ( 2/3 ) 19 - 27 2023

ORIENTED-PLANNING SOLID WASTE MANAGEMENT SYSTEM IN VIETNAM TOWARD SUSTAINABILITY - MINIMALISM OR OPTIMIZATION Reviewed

Song Toan Pham Phu, Takeshi Fujiwara, Cuong Le Dinh

Environmental Engineering and Management Journal 21 ( 9 ) 1533 - 1543 2022.9

Language：English Publishing type：Research paper (scientific journal)

In Vietnam, the rapid development of the tourism industry has led to significant challenges in the management of municipal solid waste. In Hoi An city (HAC), the solid waste management (SWM) system in the tourism area (TA) in downtown is facing many urgent problems such as the overload of waste, the inefficiency in the collection system, and the loss of revenues from tipping fee. Aiming to reduce these gaps, five scenarios of the SWM models are built based on the practical issues, the assumption on enhancing of SWM practice, improving the SWM collection, and approving the waste regulation from local government. The optimisation and feasibility of an SWM model were analysed and assessed based on the efficiency of the collection system, the enhancement of recycling practice, the consensus of stakeholders, the favourability for treatment, and the optimisation of economic benefits. The results revealed that the SWM scenario 1 (S1) and S2 get a more positive response from stakeholders (especially commercial sectors) by the high consensus and willingness to pay the higher tipping fee (1.2 times) due to the minimalism in the SWM practice at source. While S3 and S4 clearly show more optimization in sustainable waste management such as techincal efficiency, economic affordability and effective environment. The upgraded process of the SWM system is suggested to gradual apply from S0 to S3 and S4 under the monitoring of the government and the support from social organisations. It should be an oriented-plan of the SWM system in HAC toward sustainability.

DOI： 10.30638/eemj.2022.136

Developing a dataset for the expected anthropogenic mercury release in China in response to the Minamata convention on mercury. Reviewed International journal

Habuer, Takeshi Fujiwara, Masaki Takaoka

Data in brief 42 108280 - 108280 2022.6

Language：English Publishing type：Research paper (scientific journal)

This paper contains supplementary data in support of a research paper published [1] regarding the expected anthropogenic mercury release in China in response to the Minamata Convention on Mercury (MCM). The dataset provided within this article contains a set of excel spreadsheets. Each spreadsheet contains filtered (collected) and analysed data, i.e., parameters, collected data, calculated and summarized results for mercury distribution by the category of mineral production, intentional uses, secondary metal production, extraction and combustion, and waste treatment in a specific year. The collected (filtered) data in this article consist of the input factor (IF), activity rate data (ARD), output scenario (OS), initial distribution factor (iDF), and redistribution factor (rDF). IF was from the default IF in the United Nations Environment Programme (UNEP) Toolkit Level 2 and published scientific papers. ARD was obtained from the U.S. Geological Survey database, China Statistical Yearbooks, and published scientific papers. The OS content was from the default OS in the UNEP Toolkit Level 2 and published scientific papers. iDF was from the default distribution factor (DF) in the UNEP Toolkit Level 2 and published scientific papers. rDF was from published scientific paper. The mercury input was calculated using IF and ARD. The mercury release to different media in the initial distribution step was calculated using the mercury input and iDF. The release of mercury to the final sinks in the redistribution step was calculated using the amount of sector-specific treatment/disposal, product or by-product, and rDF. The dataset with combination of the collected (filtered) and analyzed data can contribute to an understanding of differences in anthropogenic mercury release before and after implementation of the MCM, especially considering technology transformation in China. Government policymakers involved in hazardous waste management, especially those working on MCM, and engineers and scientists interested in hazardous waste management may benefit from these data. The data can be used for identifying the environmental impact of anthropogenic mercury release before and after the MCM in China. The data can facilitate the creation of strategic management policies for mercury as the MCM is implemented in China.

DOI： 10.1016/j.dib.2022.108280

Greenhouse gas mitigation by integrating waste treatment system toward low-carbon city in Vietnam Reviewed

Song Toan Pham Phu, Takeshi Fujiwara, Dinh Cuong Le, Duy Bao Nguyen

Blue-Green Infrastructure Across Asian Countries: Improving Urban Resilience and Sustainability 465 - 473 2022.3

Language：English Publishing type：Part of collection (book)

Environmental pollutions and greenhouse gas (GHG) emissions are among the dark sides of development and have been one of the critical driving forces of climate change. GHG is emitted from various activities, of which the waste treatment system is a significant source. This chapter describes the results of mitigating GHG by enhancing the solid waste management (SWM) system toward a low-carbon society in Hoi An City (HAC), Vietnam. The results showed that landfilling has the highest GHG emission with 808 kg CO2-eq per tonne of waste, while incineration and composting emit on average 438 and 172 kg CO2-eq/tonne of waste, respectively. The average carbon footprint value of waste in optimal SWM system (S3 and S4) is 337 and 307 kg CO2-eq per tonne of solid waste treated. The GHG amount emitted from the minimalist SWM system (S1 and S2) is higher by 547 and 536 kg CO2-eq/tonne of waste treated, respectively. The higher the solid waste management practice, the lower the GHG emission. This study also builds the oriented planning on improving the SWM system in HAC (Vietnam in general) in the next decade. The optimal SWM scenarios (S0-S3-S4) will significantly contribute to mitigating GHG emissions.

DOI： 10.1007/978-981-16-7128-9_21

Optimization of solid waste collection system in a tourism destination Reviewed

Cuong Le Dinh, Takeshi Fujiwara, Misuzu Asari, Song Toan, Pham Phu

Global Journal of Environmental Science and Management 8 ( 3 ) 1 - 18 2022.3

Authorship：Last author Language：English Publishing type：Research paper (scientific journal)

most famous tourist destinations in the world. This led to a rapid increase in solid waste generation,leading to problems and challenges in solid waste collection and management. This problem is alsobeing experienced by other developing countries of the world. Despite the existence of establishedwaste management strategies, targets set for the collection of recyclable waste have not been met.This study introduces solutions to the problems and challenges faced by the waste managementsector in Hoi An city and other developing countries. This study aimed to i) optimize the map of therecovery recycling stations in an urban community, ii) develop an effective solid waste collectionsystem, and iii) provide management tools to enhance recycling activities, contributing to improvingwaste management in Hoi An city.METHODS: The RRSs were integrated into a solid waste collection system in the urban communitiesof Hoi An City, were conducted through location-allocation analysis in a geographic informationsystem environment. Routing problems of carts were solved in the combination of the reschedulingof existing solid waste collection activities in the study site. The economic evaluation by scenarioswas also calculated for ten years to assess the feasibility of scenarios.FINDINGS: Thirty-four locations were identified and optimized to accommodate the RRSs and newcollection routes. The distances travelled and working time increased in proportion to the increasein waste separation effectiveness. Waste separation is vital to the effectiveness of the new solidwaste collection system. The optimal solid waste practice model (in scenarios 2 and 4) revealedthe positive results in improving the solid waste collection system, operating economy, and localadaptation.CONCLUSION: This study redesigned the solid waste collection system to solve the current problemsin the tourism destination of Hoi An city. This study contributed as a case study of integrating urbanrecovery recycling stations into optimizing a solid waste collection system in a tourism destination.Introducing strict waste separation was the pivotal first step in systematically upgrading the solidwaste collection system in Hoi An City. This study’s findings provide government officials and serviceproviders with methods that can be applied to solve the problems faced by Hoi An city’s existingsolid waste collection and management system.

DOI： 10.22034/GJESM.2022.03.09

Promoting Chinese urban residents’ participation in source separation and recycling Reviewed

Binxian Gu, Yanbin Yao, Huimin Hang, Yulin Wang, Renfu Jia, Lingxuan Liu, Hui Ling, Xinyi Tang, Haijie Zhang, Zhiwei Wu, Yongxiang Wu, Takeshi Fujiwara, Yanchao Bai

Waste Management 139 290 - 299 2022.2

Language：English Publishing type：Research paper (scientific journal)

Source separation and recycling (SSR) for municipal solid waste is an important strategy for the transition to a circular economy and requires broader resident participation. How can residents’ participation in SSR be promoted? Here, we consider 13 cities in Jiangsu as microcosms of China. We quantify residents’ intentions to participate in SSR by distributing a validated questionnaire to 2,963 urban residents, analyze the results through structural equation modeling, and propose localized policy recommendations. We find that residents have positive attitudes toward SSR, although 92.6% of residents in southern Jiangsu were more willing to participate than those in northern Jiangsu (84.6%). Additionally, the influencing factors and their degree of influence on resident SSR participation intentions exhibit disparities across cities. “Accessibility of SSR facilities” simultaneously affects the 13 studied cities and is a key factor. “Environmental knowledge” and “environmental attitudes” are important impact factors, with occurrence frequencies of 84.6% and 69.2%, respectively. However, laws and regulations have no significant effect on residents’ SSR participation intentions. We recommend that the government create favorable external conditions related to facilities and services, promote extensive publicity and educational activities through various channels, and improve the effectiveness of SSR laws and regulations. Future SSR management strategies should be localized, flexible and comprehensive. This research could help decision makers in China and other countries design policy guides to promote SSR and help link current research areas to social development.

DOI： 10.1016/j.wasman.2021.12.032

Effectiveness of oyster shell as alkali additive for two-stage anaerobic co-digestion: Carbon flow analysis Reviewed

Peni Astrini Notodarmojo, Takeshi Fujiwara, Habuer, Dinh Pham Van

Energy 239 ( Part C ) 2022.1

Authorship：Last author Language：English Publishing type：Research paper (scientific journal)

The objective of this study was to investigate the carbon flow of two-stage anaerobic co-digestion of kitchen waste, agricultural waste, and horse dung using oyster shells as pH control conditioners compared with using alkalis. The anaerobic system consisted of hydrolysis reactor (hydraulic retention time (HRT) 5 d, 35 °C) and methanogenesis reactor (HRT 9 d, 35 °C). The addition of oyster shells led to hydrolysis of 40.33% ± 3.1% of the carbon, whereas alkali reactor hydrolysed almost half (48.68% ± 1.4%). In methanogenesis stage, the highest methane yield under pH adjustment by oyster shells was 580 mL/gVS; 51.05% of the carbon in methanogenesis reactor was converted into methane, generating 1.49–2.00 kWh/kgVS of energy. In comparison, methane yield with NaOH as an alkali was higher (667 mL/gVS), and 59.71% of the carbon was converted into methane, generating 1.97–2.55 kWh/kgVS of energy. To facilitate the digestion of hydrolysate produced using NaOH, we had to remove excess sludge because of sludge accumulation, whereas this was not necessary in oyster-shell treatment. Although NaOH conditioner had higher methane production performance, the oyster-shell conditioner can function as a buffer that regulates itself to keep the pH of the reactor stable with a rapid increase in the hydrogen-ion concentration.

DOI： 10.1016/j.energy.2021.122177

Reduction Potential of Anthropogenic Mercury Release in Malaysia Reviewed

Habuer, Takeshi Fujiwara

Chemical Engineering Transactions 97 205 - 210 2022

Authorship：Last author Publishing type：Research paper (scientific journal)

Anthropogenic release of mercury, human exposure and environmental health are important and mercury management policies are required to effect significant change in Malaysia. To provide a useful information to facilitate the creation of strategic management policies for mercury as the Minamata Convention on Mercury is implemented in Malaysia, there is an urgent need to estimate the potential to reduce mercury release by applying different control measures, i.e. simple electrostatic precipitator and mercury-specific filter. Equally urgent is the need to clarify the alleviated environmental burdens from the reduced mercury releases by applying different control measures. Many researches have explored issues in terms of the mercury’ toxicity and the harm of mercury compounds worldwide. A lack of surveys to evaluate both on the reduction potentials and alleviated environmental burdens of mercury releases resulted in anthropogenic sources under different control measures has been observed. This study estimated the potential reduction and alleviation of the environmental burden of anthropogenic mercury released into the natural environment (air, water and land) in Malaysia under three emission control scenarios and identified the potential reductions. A life cycle impact assessment was applied to estimate an alleviated environmental impact under these scenarios. As a result, the environmental burden can be reduced by 77 % by applying the multipollutant emission control measures such as applying mercury-specific filter for coal combustion compared to no emission control measures. At this maximum, the harm to human health can be reduced by 3,730 disability-adjusted loss of life years and the harm to ecosystems can be reduced by 0.16 species/year. This study will assist decision makers to understand the magnitude of changes resulting from different emission control measures.

DOI： 10.3303/CET2297035

Options for sustainable solid waste management in a tourist city in a developing country Reviewed

Song Toan Pham Phu, Takeshi Fujiwara, Cuong Le Dinh

Proceedings of Institution of Civil Engineers: Waste and Resource Management 2022

Authorship：Last author Language：English Publishing type：Research paper (scientific journal)

A study was undertaken to develop options for sustainable integrated solid waste management for a tourist city in Vietnam. The generation and characterisation of tourism waste were based on a sampling survey of Hoi An city (HAC). Problems and challenges of a tourism waste management system were indicated using material flow analysis. Five scenarios were developed for the tourism sector of the city based on current solid waste management practice (SWMP), a consensus of stakeholders, the suitability of waste management systems and the contribution of the government. In two of the scenarios, waste reduction was 6.5 times higher and recyclables recovered was 3.3-4.2 times greater than that in two of the minimalist scenarios. Furthermore, the former scenarios showed more efficiency in treatment, optimal economy and minimum greenhouse gas emissions. The study indicated the advantages and challenges of each scenario and identified an optimal model for SWMP for the tourism industry of HAC. A framework for gradually developing a sustainable tourism waste management system was proposed, potentially applicable to any tourist city in a developing country.

DOI： 10.1680/jwarm.22.00005

Assessment of solid waste collection system-A case study in Hai Chau district, Danang city, Vietnam Reviewed

Cuong Le Dinh, Song Toan Pham Phu, Takeshi Fujiwara, Tra Qui Phan

2022 7th International Scientific Conference on Applying New Technology in Green Buildings, ATiGB 2022 37 - 42 2022

Authorship：Last author Publishing type：Research paper (international conference proceedings)

Over the last decade, urgent problems related to the waste management system of Da Nang city have been recognized. Therefore, research on the current status of solid waste management system and solid waste collection system is gradually becoming paramount. This study applied Geographic Information System (GIS) and Global Positioning System (GPS) to study the current status of the waste collection system in Hai Chau district, Danang city. The GPS devices were utilized and in-depth interviews were also performed to collect information and data about the waste collection system. Data were synthesized, processed, and analyzed by QGIS 3.4 and Excel 2016. Four teams were in charge of solid waste collection in the entire Hai Chau district. The average daily amounts of solid waste collected were 56t (Team 1), 42.4t (Team 2), 42.6t (Team 3), and 61.1t (Team 4). The coverage ratios and physical duplication ratios of the three teams were 36.5% and 51.1% (Team 1), 55.6% and 47.1% (Team 2), 51.4% and 34.4% (Team 3). The compaction truck of Team 4 only transferred solid waste from transfer station to Khanh Son landfill. The problems and challenges of the solid waste collection system were also highlighted with recommendations for the outcomes.

DOI： 10.1109/ATiGB56486.2022.9984120

A Structure Analysis of Waste Classification Consciousness in Fu Yang, CHINA

DU Yuxin, TSUJII Hiroyuki, - Habuer, FUJIWARA Takeshi

Proceedings of the Annual Conference of Japan Society of Material Cycles and Waste Management 33 499 2022

Language：Japanese Publisher：Japan Society of Material Cycles and Waste Management

During the rapid socio-economic development of China, the amount of domestic waste has increased dramatically. Most areas collect domestic waste through mixed collection systems. The large number of informal landfill practices also results in significant loss of land resources, and they often lack adequate drainage management and are likely to contaminate soil and groundwater. One way to reduce informal landfill activities is to separate household waste. The purpose of this study was to determine the factors that determine residents' cooperation and intention to separate household waste. Based on the theory of planned behavior, a questionnaire survey was conducted among residents of Fuyang City, China, by collecting and analyzing existing studies and literature in the field of domestic waste sorting. The assumption put forward is that attitudes (A), subjective norms (SN), environmental perceptions (C), policy and publicity (PP), and perceived behavioral control (PBC), enhanced the behavioral intentions (I) of Fuyang residents toward domestic waste sorting. To assess this hypothesis, we analyzed the questionnaire data using SPSS AMOS 27, and the results showed that policy and publicity, environmental cognition, attitudes, and perceived behavior control were shown to positively influence the behavior intentions of the residents of Fu Yang city toward household waste classification.

DOI： 10.14912/jsmcwm.33.0_499

Home-Composting – A Study on the Simplicity of the System in the Application toward the Effectiveness and Feasibility in Spreading in Vietnam Reviewed

Pham Phu, Song Toan, Fujiwara, Takeshi, Nguyen, Duy Bao Dinh, Cuong Le

Chemical Engineering Transactions 89 505 - 510 2021.12

Authorship：Last author Language：English Publishing type：Research paper (scientific journal)

In 2018, the landfill in Danang city (DNC) received a significant amount of 1,073 t/d of waste, of which 54 % are bio-degradable waste, this lead to the overloaded of DNC landfill. It also shows the huge potential of composting using organic waste is being overlooked. This study aims at introducing a biowaste treatment with a conventional aerobic composting method, the T-COM V2.0 system. The model is a horizontal rotary drum with the same operating principle as the in-vessel composting system, with a capacity of 200 L, equivalent to 10 kg/d. Four models are alternately operated at DNC primary school for kitchen waste treatment, with the combination of effective microorganisms to improve decomposition efficiency and reduce odor. The Compost showed positive results with organic matter 2.5 times higher than the Vietnamese standard on organic fertilizer, odorless, non-contaminated by heavy metal, and can be applied for cultivation or improving soil condition. Within three months of operation, the system had shown efficiency impact with more than 1 t of organic waste treated and is possible to replicate at households, restaurants, hotels with outstanding features like technical assurance, economic optimization, operational simplification, and ease of application. Thus, this system can benefit the DNC waste management system by reducing the quantity of organic waste generation at source.

DOI： 10.3303/CET2189085

The response of anthropogenic mercury release in China to the Minamata Convention on Mercury: A hypothetical expectation Reviewed

Habuer, Takeshi Fujiwara, Masaki Takaoka

Journal of Cleaner Production 323 2021.11

Authorship：Last author Language：English Publishing type：Research paper (scientific journal)

The combination of anthropogenic activities and long-term atmospheric transport has resulted in a sustained increase in global mercury concentrations in air, in water and on land. The Minamata Convention on Mercury (MCM), is a global treaty with the goal of protecting human health and the environment from anthropogenic releases of mercury. This study aimed to quantify the mercury inputs and outputs in China in 2016–2019 according to five source categories and investigate the effect of an accelerated scenario/technology transformation required by the MCM on the subsequent distribution of mercury among environmental and intermediate reservoirs. Mercury releases to natural environment decreased dramatically after the MCM, such that around 840 t of mercury was released to those reservoirs in 2019, which is less than 21% of that in 2016 (1,063 t) when an accelerated scenario/technology transformation (STranf) was taken into consideration. Applying the accelerated STranf can hardly change the total release amount to the natural environment, also can reduce 53 t and 58 t of atmospheric emission in 2018 and 2019 respectively. Atmospheric emission was most sensitive to STranf, followed by emissions to land and water. This is the first attempt to provide a systematic evaluation of the effectiveness of the MCM based on the hypothetical expectations. As the MCM moves into the implementation phase, further information from scientific data and studies is critically needed to support decision-making and management. The results of this study can provide such information, facilitating the creation of strategic management policies for mercury as the MCM is implemented in China.

DOI： 10.1016/j.jclepro.2021.129089

The recyclable waste recycling potential towards zero waste cities - A comparison of three cities in China Reviewed

Binxian Gu, Xinyi Tang, Lingxuan Liu, Yuanyuan Li, Takeshi Fujiwara, Haohui Sun, Aijun Gu, Yanbing Yao, Ruiyang Duan, Jie Song, Renfu Jia

Journal of Cleaner Production 295 2021.5

Language：English Publishing type：Research paper (scientific journal)

Recycling is an essential practice for the successful operation of zero waste cities. It is essential to understand the recyclable waste recycling potential (RWRP). This study quantifies the RWRP of different cities in China. Suzhou, Yangzhou, and Suqian represent high-, middle- and low-income cities, respectively. The RWRP statistics are based on systematic multiple longitudinal tracking field surveys conducted between 2016 and 2019. Obvious RWRP spatio-temporal disparities were observed between inter-city and intra-city. For instance, Suzhou showed a slight increase in high resource value paper; Yangzhou had a slight increase in low resource value paper; and Suqian had a huge increase in no resource value paper and plastic. Additionally, more recyclable organics were generated in the old districts of Suzhou, and they were also predominant in the new districts of Yangzhou. No significant difference was observed in recyclable organics and recyclable material in Suqian. However, recyclable organics is a constant, while recyclable material fluctuates in the case cities. Household consumption structure has a major impact on RWRP. Other factors, such as economic development, urban resident population, consumption preferences, local customs and culture, as well as residential lifestyles also affect RWRP. This study proposes three policies: 1) to establish flexible and carefully planned recycling strategies, 2) to develop the distribution market of composting products, and 3) to incorporate economic and demographic initiatives to develop a workable recycling policy that can lead to zero waste implementation in the future. The zero waste concept was further assessed by the authors’ review of 69 cities worldwide based on previous research. We compared past results with the three featured cities in this study and 35 other Chinese cities, thereby presenting a world view of zero waste potential. It is anticipated that representative cities’ RWRP quantification and policy implementations can be a model for municipal solid waste management and recycling policies in other Chinese cities, which will help them transition to zero waste cities and probably provide a model for cities worldwide.

DOI： 10.1016/j.jclepro.2021.126358

Solid waste collection system in tourism destination – the status, problems and challenges Reviewed

Cuong Le Dinh, Takeshi Fujiwara, Misuzu Asari, Song Toan Pham Phu

Chemical Engineering Transactions 83 43 - 48 2021.2

Authorship：Last author Language：English Publishing type：Research paper (scientific journal)

Solid waste collection system (SWCS) plays an extremely important role in solid waste management system (SWMS). Optimization on SWCS have always been a primary mission of SWM towards sustainability. Hoi An city (HAC) is a tourist attraction in the central of Vietnam with omnipresence of tourism activities especially in tourism destination (TD). As a result, optimization of SWCS towards sustainability is crucial for TD of HAC. This study aimed to offer understandings on the current SWCS. This study was conducted with GPS (Global Positioning System) logger and QGIS 3.4 to collect and analyze data of existing SWCS. Results showed that, four modes of transportation were used for solid waste collection activities (SWCA) with almost all of sources of WG in the morning. Largest figures for total number of route (29) and amount of waste collected by carts (19.6m3) were illustrated in the morning shift (MS). Illegal solid waste collection (SWC) accounted for about 10 % of total amount of waste collected by carts. Forklift trucks were the final disposal of all SWCA in TD. Current waste gathering (WG) practices indirectly damaged the tourism activities while the improper implementation of selective waste collection at source hindered the efficiency of SWCS in TD. This study made a contribution as a scientific base for optimization and administration of SWCS.

DOI： 10.3303/CET2183008

Development of Disaster Waste Quantification Method using Mobile Mapping System Reviewed

吉川慶, 西山哲, 藤原健史

EICA 26 ( 2/3 ) 91 2021

Oyster shell as pH control substitute for two stage anaerobic co-digestion system Reviewed

Peni Astrini Notodarmojo, Takeshi Fujiwara, Habuer

Chemical Engineering Transactions 83 481 - 486 2021

Authorship：Last author Language：English Publishing type：Research paper (scientific journal)

Alkali substitute for two-stage anaerobic co-digestion system using kitchen waste, agriculture waste, and horse dung was compared with the standard alkali chemical used for pH control. The substitute used in this experiment is oyster shell waste. The study aims to investigate and evaluate the performance of oyster shells to overcome problems such as pH drops in the hydrolysis stage, greenhouse gas emission from chemical use, and methanogenesis stage performance such as methane gas yield and quality of biogas production. The result shows hydrolysate from control treatment using alkali has the highest volatile solid (VS) (1.18 %) and chemical oxygen demand (COD) (27.7 g/L). Oyster shell treatment has lower VS (1.14 %) and COD (25.01 g/L), but not significantly different from control. One-time oyster shell application can maintain reactor pH throughout the acid phase. Alkali treatment needs multiple doses to maintain the reactor in the intended pH range. At the end of the first stage, liquid hydrolysate pH value from alkali, oyster shell and no pH control treatment are 6.5, 5.29 and 3.8. As a result of comparing greenhouse gases emission in the cases of using NaOH as alkali, and oyster shell by Life Cycle Assessment (LCA) method, equivalent weight of CO2 emission from the oyster shell is lower by 0.0504 kg-CO2/kg-waste than that from alkali or only 0.15 times. In methanogenesis stage, alkali treatment produced 31 % higher methane gas yield (429.82 mL CH4/g VS in 1.64 g VS/L/d) compared to oyster shell treatment (321.32 mL CH4/g VS in 2.8 g VS/L/d). Methane gas yields of oyster treatment are stable through the different range of organic loading rate (OLR) while in alkali treatment the gas yield tends to increase in proportion with higher OLR. Highest methane gas percentage in biogas produced from alkali treatment (77.53 %), while in oyster shell treatment highest methane gas percentage is 71.11 %. Alkali treatment performs better in methane gas production using two stage anaerobic digesters, but oyster shells offer advantages in terms of practicality, stability and environmental impact.

DOI： 10.3303/CET2183081

Anthropogenic mercury release flow in China Reviewed

Habuer, Takeshi Fujiwara, Masaki Takaoka

Chemical Engineering Transactions 83 7 - 12 2021

Authorship：Last author Language：English Publishing type：Research paper (scientific journal)

China is the largest emitter of anthropogenic mercury worldwide. Implementation of the Minamata Convention on Mercury will significantly impact the development, use, and management of mercury resources. Chinese mercury management policies require significant adjustment. There is an urgent need to develop a current national mercury inventory to estimate mercury inputs and outputs by source category, and to clarify the distributions to various environmental scenarios. Here, the mercury releases are quantitatively analysed to facilitate the implementation of strategic mercury management policies in China. First, the mercury inputs and outputs by source categories in 2016 are quantified and then the mercury distributions to various environmental and intermediate sinks are estimated. The total mercury input was 5,116 t in 2016, of which 77 % was attributable to mineral production. In total, 3,083 t were released into various environmental and intermediate reservoirs. Of this total, 53.8 % was intentional uses, followed by extraction and combustion (26.5 %), and mineral production (19.6 %); 1,501 t were released into air, water, and land, of which extraction and combustion accounted for 48.6 % followed by mineral production (25.7 %) and intentional uses (25.6 %).

DOI： 10.3303/CET2183002

Analyzing the characterization of municipal solid waste in Da Nang City, Vietnam Reviewed

Song Toan Pham Phu, Takeshi Fujiwara, Naoya Akasaki, Dinh Cuong Le, Hoang Minh Giang, Pham van Dinh

Chemical Engineering Transactions 83 241 - 246 2021

Authorship：Last author Language：English Publishing type：Research paper (scientific journal)

Recently, most cities in Vietnam are facing waste problems that are mainly caused by the rapid increase of municipal solid waste (MSW) amount and the limitations of the MSW management system. This study aims to characterise the waste generation, composition and characteristics of MSW in Da Nang city, which is one of the five biggest cities in Vietnam. The current problems and challenges of MSW system are also analysed. The sampling survey was conducted in the dry and wet seasons in August and November 2018. The MSW was taken directly from trucks at the landfill site with the sample size by 500 kg/waste sources. This study shows that the simultaneous development of production, trade and service activities in the last decade has led to the speedy growth of waste by 9 %/y, and reached 1,073 t/d in 2018. In which, waste generated from industry and the hospitals account inconsiderable proportions by 3.9 % and 1.4 %. This study also indicated that the MSW generation rate from the urban areas is more than that of the coastal and industrial areas. For the composition of MSW, biodegradable waste and recyclables are the main components with the proportion of 54 % and 27 % of the total waste. While the waste composition almost do not differ considerably by seasons, the difference in the characteristics of waste is a consideration for the processing. The current problems and solutions to improve the MSW system toward sustainability are also discussed and suggested.

DOI： 10.3303/CET2183041

Life Cycle Impact Analysis of Anthropogenic Mercury Release in Malaysia Reviewed

Habuer, Muhamad Nabil Fikri Bin Abdul Hamid, Takeshi Fujiwara

Chemical Engineering Transactions 89 265 - 270 2021

Authorship：Last author Language：English Publishing type：Research paper (scientific journal)

Anthropogenic activities have aroused great concern in terms of the negative impact on ecosystems and human health. With rapid industrial development, Malaysia has experienced problems with regard to mercury pollution. Knowledge of the mercury emission and release inventory, and the main factors that ameliorate the environmental impact of anthropogenic activities, will contribute to environmentally sound mercury management, which is becoming increasingly urgent in Malaysia. In this study, inventories for total mercury emission and release in 2019 were devised to understand pollution sources. A life cycle impact assessment was used to identify the major factors contributing to the overall environmental burden. The environmental impact of anthropogenic mercury releases was compared between (sub)source categories. The total mercury input in 2019 was 36.4 t, of which 30.4 t were released to the natural environment under the output scenario of mercury release with no emission control. The respective amounts of 12.7, 1.8, and 15.9 t of mercury were released to air, water, and land. The environmental burden to terrestrial ecosystem imposed by mercury release was higher than that to freshwater and marine ecosystems. The harm to human health was 4,785 DALY, and harm to ecosystem was 0.85 species/y. The category of coal combustion was the largest contributor to the harms of human health (44 % of total impact), followed by cement production (11 % of total impact), and natural gas extraction and combustion (11 % of total impact). The category of gold mining (no amalgamation) was the largest contributor to the harms to ecosystems (76 % of total impact), followed by coal combustion (11 % of total impact). The result of this study can provide a scientific information to policymaker for strategic management of mercury in Malaysia.

DOI： 10.3303/CET2189045

Performance of Oyster Shell Powder Size on Methane Gas Generation in Two-Stage Anaerobic Digestion System Reviewed

Peni Astrini Notodarmojo, Takeshi Fujiwara, Habuer, Mochammad Chaerul

Chemical Engineering Transactions 89 373 - 378 2021

Authorship：Last author Language：English Publishing type：Research paper (scientific journal)

An anaerobic digester system is a sequence of process to digest biodegradable waste into biogas in the absence of oxygen. In two-stage anaerobic digestion system acid-forming steps or hydrolysis stage are separated from the methane forming steps. Although hydrolysis stage tends to get too acidic, addition of alkali substance can prevent pH from dropping too low so as to maintain good decomposition condition for microorganism. Oyster shell powder is a useful pH control additive containing CaCO3 at high percentage that can neutralize acid. In this study, the performances between industry-made fine oyster shell (IOS) powder (size 10.5 μm) and manually ground oyster shell (OS) powder (size < 1 mm) in methane generation yield were compared. NaOH, which is an alkali reagent for controlling pH, also used in comparison. The result showed that at the end of the hydrolysis stage, IOS powder increased pH up to 6.63, NaOH did almost the same (6.72), and OS powder was the lowest (6.1). In liquid residue, ratio of inorganic ash content with IOS treatment was the highest (2.1 %), but OS was the lowest (1.4 %). In the methanogenesis stage, CH4 concentration with NaOH treatment was the highest (80 %) compared to oyster shell powders: 74.33 % in IOS and 74.24 % in OS. Average methane yield over observation period of IOS treatment was the highest (533.9 mL/gVS), followed by alkali (487.3 mL/gVS) and OS (413.7 mL/gVS). Total CH4 from IOS treatment was 37 % and 8 % higher than OS and alkali treatment. Powder size of oyster shell greatly affected pH control, methane yield, and solid-liquid separation, but not methane concentration. Using IOS powder as pH control in hydrolysis of two-stage anaerobic system resulted in 78 % less cost than using NaOH.

DOI： 10.3303/CET2189063

Waste Segregation at Source and Separately Collection - The Inadequacy in Implementation in Vietnam Reviewed

Cuong Le Dinh, Takeshi Fujiwara, Song Toan Pham Phu

Chemical Engineering Transactions 89 499 - 504 2021

Authorship：Last author Publishing type：Research paper (scientific journal)

Hoi An city is a dynamic tourism city in Vietnam which had received the certificate of World Heritage Site by UNESCO. The boom in tourism activities led to problems for the solid waste management system. Solid waste collection activities account for the largest proportion of expenses on solid waste management. Optimization of the present solid waste collection system of Hoi An city is an urgent mission. This research is an effort to describe the current solid waste collection system of Hoi An city with the support of GIS and GPS. The results denoted Thursday, Friday, and Saturday accounted for the most enormous workload with 36, 34, and 40 trips. The total working time for these days were 103.86, 96.12, and 109.6 h while the total traveled distances were 733.76, 719.21, and 848.12 km. The complexity of solid waste collection routes, frequencies of solid waste collection, and coverage of solid waste collection activities decreased from urban areas to rural areas. Collection of waste accounted for the largest amount of time in solid waste collection activities. The low rate of waste separation at source, illegal solid waste collection, extreme weather, misbehaviours of drivers and workers, as well as the limitation in waste treatment facilities were the problems and challenges of the solid waste collection system in Hoi An city.

DOI： 10.3303/CET2189084

Environmental Impact of Anthropogenic Mercury Release in China Reviewed

Habuer, Takeshi Fujiwara, Masaki Takaoka

Chemical Engineering Transactions 89 301 - 306 2021

Authorship：Last author Language：English Publishing type：Research paper (scientific journal)

There is increasing public concern regarding the potential risks posed by mercury and mercury compounds. Knowledge of the mercury emission and release inventory, and determination of the main factors that ameliorate the environmental impact of anthropogenic activities, will contribute to environmentally sound mercury management. This study used a life cycle impact assessment to identify the major factors contributing to the overall environmental burden imposed by elemental mercury releases. The environmental impact of the business-as-usual scenario (total impacts = 5.13 GPt) was greater than that of the accelerated technology transformation (ACR) scenario (total impacts = 4.51 GPt), especially in terms of the impact on human health (HH). ACR mainly reduces mercury emissions to air, which affects HH. Compared to its effects on HH, mercury release to the environment has less impact on ecosystem diversity (ED). Mercury release to land had the largest impact on ED, followed by mercury emissions to air and discharge to water. ACR can reduce the harm to HH and marine ecosystems by 12 %. This study provides quantitative information on the environmental impact of mercury release, facilitating strategic management of mercury emissions in line with the Minamata Convention on Mercury (implemented in China in 2017).

DOI： 10.3303/CET2189051

Comparison Between Single and Two-Stage Anaerobic Digestion of Vegetable Waste: Kinetics of Methanogenesis and Carbon Flow Reviewed

Dinh Pham Van, Fujiwara Takeshi, Giang Hoang Minh, Song Toan Pham Phu

Waste and Biomass Valorization 11 ( 11 ) 6095 - 6103 2020.11

Language：English Publishing type：Research paper (scientific journal)

Abstract: This study aims to compare the performance and kinetics between the single-stage anaerobic digestion (SAD) and the two-stage anaerobic digestion (TAD) of vegetable waste (VW). The SAD was performed using continuously stirred tank reactors. Meanwhile, the TAD experiment was set up using a combined system involving a continuously stirred tank for hydrolysis/acidogenesis and an upflow reactor for methanogenesis. The hydrolytic reactor operated as a batch process with a retention time (RT) of 9 days, while the methane reactor was a continuous process operation with RT of 20 days. Both TAD and SAD were controlled at a temperature of 36 °C. The SAD experiments lasted for 143 days, and were characterised by the kinetic rate constant k = 0.02 day−1 which was much lower than that for the TAD (k = 0.66 − 2.16 day−1). The SAD seemed to be inhibited by high concentration of free ammonia and low inoculum to substrate ratio; herein, only 17.8–22.3% of the initial carbon could be converted into biogas (equivalent to 91–110 Nml/g-VSadded) with low methane content (44.1–48.7%). Meanwhile, TAD converted 41.67% initial carbon to biogas (equivalent to 299.0–374.6 Nml/g-VSadded) with high methane content (71.68–81.0%). Moreover, methanogenesis in the TAD was highly stable which enabled the digestion process to return to normal state within a few days, even though the concentrations of the influent increased to double (6.5–24.5 g-COD/l). As per these results, the TAD was much more stable, faster, and stronger than the SAD. Graphic Abstract: [Figure not available: see fulltext.]

DOI： 10.1007/s12649-019-00861-0

Enhancing waste management practice - The appropriate strategy for improving solid waste management system in Vietnam towards sustainability Reviewed

Song Toan Pham Phu, Takeshi Fujiwara, Giang Minh Hoang, Dinh Van Pham, Hoa Kieu Thi, Yen Anh Tran Thi, Cuong Dinh Le

Chemical Engineering Transactions 78 319 - 324 2020.2

Language：English Publishing type：Research paper (scientific journal)

This study aims to build the appropriate model of waste management practice (WMP) towards sustainable municipal solid waste (MSW) system in a city of developing country like Vietnam. A waste audit was performed and material flow analysis method was simulated to describe and analyse the current status of MSW system and its assumpted models. Four WMP models were built based on the feature of the region, the intention and optimisation of WMP, and the consensus of the government. This study shows that the improvement of the SWM system can reduce a significant amount of waste to landfill. Notably, the waste reduction performance is 5.0, 7.8, 11.11 and 29.3 % in S1, S2, S3 and S4, respectively. Also, the recovery performance of recyclables changes in proportional to the level of SWM practice and reach at 3.78, 5.843, 4.593, and 7.120 t/d, respectively. This study reveals that the improvement of SWM practice at source from intentional to optimal rate is the sustainable strategy for developing an SWM system in Hoi An City.

DOI： 10.3303/CET2078054

A review of anaerobic digestion systems for biodegradable waste: Configurations, operating parameters, and current trends Reviewed

Dinh Pham Van, Takeshi Fujiwara, Bach Leu Tho, Pham Phu Song Toan, Giang Hoang Minh

Environmental Engineering Research 25 ( 1 ) 1 - 17 2020.2

Language：English

With benefits to the human health, environment, economy, and energy, anaerobic digestion (AD) systems have attracted remarkable attention within the scientific community. Anaerobic digestion system is created from (bio)reactors to perform a series of bi-metabolism steps including hydrolysis/acidogenesis, acetogenesis, and methanogenesis. By considering the physical separation of the digestion steps above, AD systems can be classified into single-stage (all digestion steps in one reactor) and multi-stage (digestion steps in various reactors). Operation of the AD systems does not only depend on the type of digestion system but also relies on the interaction among growth factors (temperature, pH, and nutrients), the type of reactor, and operating parameters (retention time, organic loading rate). However, these interactions were often reviewed inadequately for the single-stage digestion systems. Therefore, this paper aims to provide a comprehensive review of both single-stage and multi-stage systems as well as the influence of the growth factors, operating conditions, and the type of reactor on them. From those points, the advantages, disadvantages, and application range of each system are well understood.

DOI： 10.4491/eer.2018.334

Waste-to-landfill reduction: Assessment of cost-effective solutions using an optimisation model Reviewed

Giang Minh Hoang, Song Toan Pham Phu, Takeshi Fujiwara, Dinh Van Pham

Chemical Engineering Transactions 78 511 - 516 2020

Language：English Publishing type：Research paper (scientific journal)

Significant increases in solid waste generation and inappropriate waste management system leads to overloaded landfills, which have negative impacts on the environment and human health. Reducing waste sent to landfill has become an emerging mission in Vietnam. This study aims at assessing cost-effective solutions to reduce waste-to-landfill amount using system analysis approach. A single-objective optimisation model is formulated to minimise the cost of the system in association with different landfill waste reduction targets and values of waste separation efficiency for Hoi An city. As a result, the landfill target is directly proportional to the cost. It means the higher landfill reduction target leads to the higher cost of the system. Meanwhile, the separation efficiency is inversely proportional to the system cost. The result showed that twenty-five percent of municipal waste treated in landfills is achievable target based on the current condition of the city. Also, ten percent of municipal waste sent to landfill is an infeasible mission if the waste separation rate is too low. If waste is wholly separated at source, incineration, composting and landfill can be applied as main treatment alternatives to reduce seventy-five percent of municipal waste sent to landfill with the cost of about 1,800 USD/d.

DOI： 10.3303/CET2078086

Solid waste management practice in a tourism destination – The status and challenges: A case study in Hoi An City, Vietnam Reviewed

Song Toan Pham Phu, Takeshi Fujiwara, Giang Hoang Minh, Dinh Pham Van

Waste Management and Research 37 ( 11 ) 1077 - 1088 2019.11

Authorship：Last author Publishing type：Research paper (scientific journal)

This study aims to present waste characterisation, solid waste management practice and analyse the challenges in the solid waste management system in the tourism destination of Hoi An City, Vietnam. The sampling and questionnaire surveys were conducted for measuring characterisation and management practice of solid waste. A material flow analysis method was used for analysing the waste flow. The results show that the tourism destination generated daily around 15080 kg t of waste, in which the significant proportions come from restaurants (46%), hotels (22%) and households (13%). The feature of the waste composition is high rates of kitchen waste (46.8%), tissue (11.54%) and recyclable materials (12.58%), which result in high moisture (46.79%) and a low heating value (16,866 kJ kg-1) of waste. Also, solid waste management practices were evasively implemented by stakeholders with low rates and efficiency. Furthermore, a substantial gap of the solid waste management system is the confusion in waste collection activities, which is shown by the overload of waste in street bins and the financial loss for the solid waste management system owing to the non-compliance with collection regulation of stakeholders. Also, the mixing of waste by collection crews after separation at sources, the in-appropriation of collection time and manner are the dark points of the solid waste management system that may be causes of the non-cooperation of stakeholders. These gaps and confusion in the solid waste management system are the significant challenges in the improvement of the solid waste management system in the tourism destination toward sustainability.

DOI： 10.1177/0734242X19862042

Sustainable solid waste management system using multi-objective decision-making model: a method for maximizing social acceptance in Hoi An city, Vietnam Reviewed

Giang Minh Hoang, Takeshi Fujiwara, Toan Song Pham Phu, Luong Duc Nguyen

Environmental Science and Pollution Research 26 ( 33 ) 34137 - 34147 2019.11

Publishing type：Research paper (scientific journal)

The main aim of this study was to develop a decision support system for sustainable municipal solid waste management (MSWM) in Hoi An city (HAC), Vietnam. A face-to-face interview was conducted with local experts including authorities, citizens, waste collection contractors and recyclers to identify main objectives of waste management system and appropriate treatment methods. A multi-objective optimization model was proposed using non-linear programming approach. An interactive method known as reference point method (RPM) was applied for solving the problem with three objectives including cost minimization, landfill minimization and emission minimization. As a result, the efficient waste-flow-allocation and the optimal capacity of disposal facilities were determined by intense discussion and agreement among decision-makers. Waste incineration, anaerobic digestion, sanitary landfill and current recycling activities should be applied with a cost of about 2300 US$ daily. Also, the daily emission of various pollutants was about 35 metric tons, and the greenhouse gas (GHG) is 313 tons CO2-eq.

DOI： 10.1007/s11356-018-3498-5

The fate of carbon in two-stage anaerobic digestion of vegetable waste Reviewed

P. V. Dinh, T. Fujiwara, H. M. Giang, S. T. Pham Phu

IOP Conference Series: Earth and Environmental Science 307 ( 1 ) 2019.8

Authorship：Last author Publishing type：Research paper (international conference proceedings)

This study aims to investigate the fate of carbon in two-stage anaerobic digestion (TAD) of vegetable waste. The TAD including a hydrolytic reactor and a methane reactor were controlled at mesophilic temperature (36 ± 1°C) with a retention time (RT) of 9 days and 20 days, respectively. Carbon tracking was conducted step by step throughout the system. Non-hydrolysable carbon accounted for a significant proportion of total initial carbon (25%). Meanwhile, a large amount of carbon in the feedstock (23.5%) was hydrolysed but remained in the effluent including water and suspended solids. It was mostly inorganic carbon which is not harmful to the environment. The only 41.3% initial carbon was converted to biogas in both reactors. In the hydrolytic reactor, biogas was mainly carbon dioxide (99%), accounted for 11.3% of total biogas and 35.8% of total CO2 product. In the methane reactor, biogas was 373.9 Nml/g-VS including 73.3% CH4, 21.9% CO2 and 4.8% others. Non-hydrolysable materials can be a source of thermal energy. Meanwhile, a large amount of hydrolysed carbon was not converted into biogas, was still in the effluent, it was a significant energy loss. Therefore, how to further increase the effectiveness of TAD is an issue that needs to study.

DOI： 10.1088/1755-1315/307/1/012019

Assessment of public-private partnership in municipal solid waste management in Phnom Penh, Cambodia Reviewed

Vin Spoann, Takeshi Fujiwara, Bandith Seng, Chanthy Lay, Mongtoeun Yim

Sustainability 11 ( 5 ) 1228 2019.3

Authorship：Last author Language：English Publishing type：Research paper (scientific journal)

The overall responsibility for waste management in Phnom Penh Capital (PPC) has rested with the municipal authorities and contracted waste collection companies. Providing waste collection services is a major challenge for Phnom Penh due to the increasing waste volume and the deficiency of the system under public-private partnership. In response to continuing population growth and urbanization, sustainable management is necessary. This study reviewed the details of the processes and examined the performance of the private sector and local government authorities (LGAs). The study used sustainability assessment, according to a success and efficiency factor method. This assessment method was developed to support solid waste management in developing countries. Multiple sustainability domains were evaluated: institutional, legislative, technical, environmental and health aspects as well as social, economic, financial and critical aspects. The results indicate that the long-term contract design attempts for partnership may actually result in a worsening of the situation by facilitating new ways of concentration, inefficiency and political interest. The limited institutional capacity of the public sectors is a consequence of the inefficient decentralization of municipal solid waste management (MSWM) policies. Public-private partnerships can be neither effective nor sustainable if LGAs and CINTRI co. Ltd. waste collection company do not build proper incentives into their management of the two sectors. Revisiting the legal framework, establishing a facilitating agency that will assist in the design and the nurturing of partnerships, competitive tendering, and transparency and financial accountability are essential elements for PPP on the provision of waste services in PPC.

DOI： 10.3390/su11051228

Waste separation at source and recycling potential of the hotel industry in Hoi An city, Vietnam Reviewed

Song Toan Pham Phu, Takeshi Fujiwara, Minh Giang Hoang, Van Dinh Pham, Minh Thao Tran

Journal of Material Cycles and Waste Management 21 ( 1 ) 23 - 34 2019.1

Authorship：Last author Publishing type：Research paper (scientific journal)

This study focuses on assessing the practice of waste separation at source and evaluating the recycling potential of the hotel industry in Hoi An City (HAC), which is a famous tourism city in the centre of Vietnam. Five recycling scenarios were designed based on the status and intention of waste management practices of the hotels and the hierarchical structure of recycling, which was identified by the analytic hierarchy process method. This study revealed that the solid waste management (SWM) system of the hotel industry in HAC has a high potential for developing recycling practices. The high percentage of recyclable materials (84.3%), the achievements of waste separation practices, and the intentions of SWM of the hoteliers are favourable conditions for enhancing recycling practices. Furthermore, this study indicated that recycling could reduce 30–70% of total hotel waste, lead to beneficial changes in waste characterisation for incineration and composting processes, and bring economic profits to the hotels. In addition, recycling strategies with the synchronous combination of improvement of waste separation at source, waste regulation promulgation, and enhancement of waste management motivation for the hotels were discussed.

DOI： 10.1007/s10163-018-0807-5

An analysis of the commercial waste characterisation in a tourism city in Vietnam Reviewed

Song Toan Pham Phu, Fujiwara Takeshi, Hoang Minh Giang, Pham Van Dinh

International Journal of Environment and Waste Management 23 ( 3 ) 319 - 335 2019

Authorship：Last author Language：English Publishing type：Research paper (scientific journal)

This study provided a detailed description of the waste generation, composition, and characterisation of the commercial activities in a tourism city in Vietnam. Whereby, solid waste from 55 restaurants, 110 shops, 27 handcraft facilities and five markets were collected and classified into 17 categories. Then, physical and chemical characterisations of waste were analysed. The results showed that the commercial waste accounted for 35.1% of municipal waste, in which restaurants were the most significant waste source by 74.5%. The composition of commercial waste was 66.8% for biodegradable waste, 20.1% for recycling materials, 11.3% for combustible waste, and 1.8% for the others. Also, the high moisture content and density, and the low heating value were the characteristics of the commercial waste in a tourism city in Vietnam. Solutions of waste minimisation and improvement of waste quality for incineration were suggested toward the sustainable solid waste management practice.

DOI： 10.1504/IJEWM.2019.099015

Analyzing solid waste management practices for the hotel industry Reviewed

S. T. Pham Phu, M. G. Hoang, T. Fujiwara

Global Journal of Environmental Science and Management 4 ( 1 ) 19 - 30 2018.12

Authorship：Last author Language：English Publishing type：Research paper (scientific journal) Publisher：Iran Solid Waste Association

The current study aims to analyze waste characteristics and management practices of the hotel industry in Hoi An, a tourism city in the center of Vietnam. Solid wastes from 120 hotels were sampled, the face-to-face interviews were conducted, and statistical methods were carried out to analyze the data. The results showed that the mean of waste generation rate of the hotels was 2.28 kg/guest/day and strongly correlated to internal influencing factors such as the capacity, the price of the room, garden, and level of restaurant. The differences in waste generation rate of the hotels were proved to be statistically significant. The higher the scale of hotels, the higher the waste generation rate. Moreover, the waste composition of the hotels was identified by 58.5% for biodegradable waste, 25.8% for recyclables and 15.7% for others. The relative differences in the waste composition of the hotels by climate, the features of hotels, and the types of the guest were explained. Whereby, the higher size of the hotels, the higher percentage of biodegradable and less proportion of recyclable waste. Also, this study revealed that the implementation status of waste management practices of the hoteliers initially reaped quite positive achievements with 76% for sorting, 39% for recycling, 29% for reduction, and 0.8% for composting. The rate of waste management practices was proportional to the scale of the hotel. This study provided information on waste management practice of hotel industry and contributed to the overall assessment of municipal solid waste management practices of Hoi An city.

DOI： 10.22034/gjesm.2018.04.01.003

Kinetics of carbon dioxide, methane and hydrolysis in co-digestion of food and vegetable wastes Reviewed

D. Pham Van, G. M. Hoang, S. T. Pham Phu, T. Fujiwara

Global Journal of Environmental Science and Management 4 ( 4 ) 401 - 412 2018.9

Authorship：Last author Language：English Publishing type：Research paper (scientific journal)

Kinetic models which can express the behaviors of hydrolysis and biogas generation more precisely than the conventional models were developed. The developed models were evaluated based on the experimental data of six batch reactors. Anaerobic digestion test was co-digestion of food and vegetable waste with inoculating horse dung by 15% of the total wet weight, at the temperature of 37°C. For hydrolysis, the modified model was developed from an original first-order kinetic model. The modified first-order kinetic model was proved to be better than the original one with the hydrolysis rate constant in the range of 0.22- 0.34/day and hydrolyzable rate of 0.80 to 0.84. Kinetics of carbon dioxide and methane were developed from a current potential model. The comparison between experimental data and modeling values had the high correlation of determination (0.9918-0.9998) and low root mean square errors (0.08-4.51) indicating the feasibility of the developed model. In which, the evolution of methane showed the rate constant in the range of 0.031-0.039/day. The carbon dioxide from fermentation accounted for 12-44% of the total observed carbon dioxide. Thus, separation of fermentation and methanogenesis by various reactors may reduce the price of methane enrichment significantly. There was a lag time between methanogenesis and fermentation in reactors (λ = 7-11 days). Also, the biogas yield was in the range of 431.6-596.9 Nml/g-VS with the CH4 concentration of 56.2-67.5%. The best methane yield (393.7 Nml/g-VS) was in a reactor with food waste to the vegetable waste ratio by 1.8:1 (wet basis) and C/N ratio by 25.4.

DOI： 10.22034/gjesm.2018.04.002

Kinetic of Biogas Production in Co-Digestion of Vegetable Waste, Horse Dung, and Sludge by Batch Reactors Reviewed

P. V. Dinh, T. Fujiwara, S. T.Pham Phu, M. G. Hoang

IOP Conference Series: Earth and Environmental Science 159 ( 1 ) 2018.6

Authorship：Last author Publishing type：Research paper (international conference proceedings)

Batch experiments were performed firstly to evaluate co-digestion of vegetable waste (VW), horse dung (HD), and sludge (S). All reactors were set at a temperature of 37°C, pH of 6.7, and total solid 2.5%. Each single-substrate in the mixture played a significant role. In which, VW contributed mainly to the formation of biogas yield, S and HD played nutrient balance role. The biogas yield was in the range of 168-554 Nml/g-TS. Especially, the biogas yield could be estimated from the proportion of the substrates by equation G1Nml/g-TS = 53.7 + 7.448 × VW(%) + 1.922 × HD(%) or from nutrient ratio (C/N) by equation G2Nml/g-TS = 1341 - 48.46 × C/N. Further, the experimental data was applied to evaluate the kinetic equations of biogas production including the Gompertz (G) and Logistic (L) models. Constants in both models were found out by using the least squares fitting method. Both models showed high potential, in which, G model was completely better than L model. However, both models failed at time t=0 day. Moreover, the constant λ in models did not reflect the right definition itself, it was merely a mathematical constant.

DOI： 10.1088/1755-1315/159/1/012041

Enabling low-carbon emissions for sustainable development in Asia and beyond Reviewed

Chew Tin Lee, Jeng Shiun Lim, Yee Van Fan, Xia Liu, Takeshi Fujiwara, Jiří Jaromír Klemeš

Journal of Cleaner Production 176 726 - 735 2018.3

Over 90% of economies in Asia have submitted the mitigation objectives in the Intended Nationally Determined Contribution (INDC) for reducing GHG emissions targets and communicating other relevant climate policy actions. It is crucial to continuously monitor the achievement of this GHG mitigation targets using monitoring tools and evidenced by scientific methods. This Special Volume (SV) is devoted to presenting feasible cleaner technologies supported by environmental assessment tool to enable the transition of Asia into a low-carbon-emission economy. A half of the Asia emissions reduction through 2050 is contributed by low-carbon-emission energy production and another third from energy efficiency measures, with the rest achieved by curtailing emissions from forest deforestation, land degradation, and other non-energy sources. The concept of enabling low carbon emissions is not just reducing the CO2 equivalent (eq.), it concerns on other negative impacts of the emission on the whole ecosystem such as particle matter and other emissions (NOx, O3, and SOx) that are threatening the air quality and premature. Carbon emissions from the major sectors of energy, transportation, and industrial waste with the focus of presenting feasible cleaner practices or technologies to enable the implementation of sustainable development in Asia are presented. Life cycle and environmental management study on the assessment methods for environmental impact prevention, control or minimisation. Waste to wealth presented the cleaner technologies developed to convert waste resources into valuable products to promote a green economy. Process system engineering and LCA tools are widely applied in the energy sector; they could be applied to other sectors as well as to evaluate the sustainability performance index. On-going efforts are essential to close the gaps among technology providers, government sectors and investor to enable a low-carbon emissions transition in Asia.

DOI： 10.1016/j.jclepro.2017.12.110

Life cycle assessment and life cycle costing toward eco-efficiency concrete waste management in Malaysia Reviewed

Chooi Mei Mah, Takeshi Fujiwara, Chin Siong Ho

Journal of Cleaner Production 172 3415 - 3427 2018.1

Authorship：Last author Language：English Publishing type：Research paper (scientific journal) Publisher：Elsevier Ltd

The large amount of concrete waste (CW) generated during the construction and demolition stages and the improper management of it often results in considerable environmental impact. The main purpose of this study is to identify the most eco-efficiency scenario in CW management. The life cycle assessment (LCA) modelling is used to assess the environmental impact, GHG emissions and the life cycle cost (LCC) is used as an extension of LCA in the term of economic dimension. Decision making in waste management often come hand in hand with economic incentives. Aligning both LCA and LCC in environmental-cost effectiveness as the eco-efficiency analysis helps in measuring sustainability. Scenarios were built to access different CW options. Scenario 1 (S1) depicts the landfilling. Scenario 2, 3, and 4 (S2, S3, &amp
S4) are the recycling scenario where CW is recycled into concrete aggregate (RCA) to substitute the natural aggregate (NA) in road construction and in recycled aggregate concrete (RAC) production. Results show that S3, recycling of CW to substitute NA in concrete production has the highest eco-efficiency of 1.72 while landfilling has the lowest eco-efficiency of 1.15. Higher eco-efficiency means lower environmental and cost impacts. CW is preferably uses as a substitution of the NA to reduce the need in mining of NA. This study also identified that transportation distances and mining activity are the main contributors to GHG emissions and cost impact. Sensitivity analysis evaluated the what-if scenario of building a mobile material recovery facilities (MRF) within 3 km from waste source site. The results show that the what-if scenario (S3’ with 1.78 eco-efficiency) could possibly reduces 50.8% GHG emissions and 68.1% of cost saving as compared to landfilling scenario.

DOI： 10.1016/j.jclepro.2017.11.200

Suitability assessment for handling methods of municipal solid waste Reviewed

B. Seng, T. Fujiwara, B. Seng

Global Journal of Environmental Science and Management 4 ( 2 ) 113 - 126 2018

Authorship：Last author Language：English Publishing type：Research paper (scientific journal) Publisher：Iran Solid Waste Association

Solid waste management is challenging in Phnom Penh city, Capital of Cambodia. The only one formal treatment taken is the final disposal of mixed waste into an open dumpsite. The current study analyses the physical and chemical characteristics of municipal solid waste disposed of in the dumpsite to assess their suitable handling methods. The current study found that the major compositions of waste are food waste (49.18%) and plastic (21.13%), and recyclable waste shares about 17.28% of the total. On average, it contains 60.92% moisture, 35.89% combustible, 3.19% ash, 58.32% carbon and 1.05% nitrogen. High calorific value is 10.03 MJ/kg when the low calorific value is 7.77 MJ/kg. The moisture content is too high to meet the technology demands, especially in the rainy season. It seems workable for incineration without energy recovery. Gasification for melting and incineration with energy recovery are only suitable for the dry season. If the solid waste is well pre-separated, material recovery could be one of the suitable handling methods. Food waste, wood and leave could be digested in the one-stage continuous wet system and co-composted, and plastic is appropriate for refuse-derived fuel generation. The study recommends that the waste pre-separation should be requisite for any handling methods.

DOI： 10.22034/gjesm.2018.04.02.001

Challenges and lessons learnt from a community-based food waste composting project in Johor Reviewed

Nur Farzana Ahmad Sanadi, Norfhairna Baharulrazi, Nur Naha Abu Mansor, Takeshi Fujiwara, Chew Tin Lee

Chemical Engineering Transactions 63 355 - 360 2018

Language：English Publishing type：Research paper (scientific journal)

A series of Low-Carbon Society (LCS) Blueprint has been launched in Iskandar Malaysia (IM) region since 2012. The public must be equipped with fundamental knowledge and skills related to the LCS work conducted collectively through a structured network of like-minded individuals and receive technical support and monitoring from experts and practitioners. This paper presents the lessons learned from a community-based food-waste composting program, a low-carbon action outlined under the IM LCS Blueprint, at Layang-layang, Johor as a case study. Selected volunteers in SC Jaya Sepakat, with the support by Mini Rural Transformation Centre (MRTC) have been trained and were given home composting kits. A centralised composting site was set up where one volunteer has been identified as the key player to manage daily composting operation. Food waste bins were collected and converted into compost through a five-step process at the composting site. A technical advisor from Universiti Teknologi Malaysia transferred the knowledge and technology to the villagers in terms of hands-on training, overall operation, compost quality analysis and post-application study of compost on plants. This study aims to empower the community to implement the food waste composting practices in a sustainable manner that would fulfill the societal and economic needs. The challenges and lessons gained through the 8 months engagement are reported. Post-training and end of project surveys were conducted to assess the performance of the community engagement. The survey concluded that the volunteers require extrinsic motivation from external organisations to continue the LCS initiatives until a tangible economic impact is generated. Community's daily commitment and limited communication facilities in rural areas made continuous engagement a challenge. The project also drew a lesson of importance in collaboration with different stakeholders for greater impact and optimisation in resources that would require further study.

DOI： 10.3303/CET1863060

A new kinetic model for biogas production from co-digestion by batch mode Reviewed

D. Pham Van, G. Hoang Minh, S. T. Pham Phu, T. Fujiwara

Global Journal of Environmental Science and Management 4 ( 3 ) 251 - 262 2018

Authorship：Last author Language：English Publishing type：Research paper (scientific journal)

Coming out from the growth kinetics, the Gompertz model has been developed and considered as the best one for simulating the biogas production from anaerobic digestion. However, the model has failed to describe the starting point of the process, and no-sense of lag phase constant has been pointed out. Thus, the goal of this study is to develop a new kinetic model of biogas production with meaningful constants that can alternate the Gompertz model. The kinetic constants of the model were determined by applying the least squares fitting method for experimental data. The experimental data were taken from running seven batch reactors of co-digestion of vegetable, sludge and horse manure under 37oC, pH of 6.7, and total solids of 2.5%. The result of the high coefficient of determination (0.9611- 0.9906) demonstrated that the new biogas production kinetic model was feasible to simulate the biogas generation process. This finding has opened a new choice that can deal with simulation of the biogas production. Moreover, co-digestion of vegetable, horse manure, and sludge was also evaluated under strong attention. The biogas potential was in the range of 183-648 Nml/g-VS with the best carbon-tonitrogen ratio of 16. Vegetable waste played a major role in producing the biogas yield while horse manure and sludge contributed to balancing nutrient of the digestion process. Also, the strong correlation between carbon-to-nitrogen ratio and kinetic constants confirmed that the carbon-to-nitrogen ratio was the key factor that influenced biogas generation.

DOI： 10.22034/GJESM.2018.03.001

Households’ knowledge, attitudes, and practices toward solid waste management in suburbs of Phnom Penh, Cambodia Reviewed

Bandith Seng, Takeshi Fujiwara, Vin Spoann

Waste Management and Research 36 ( 10 ) 993 - 1000 2018

Authorship：Last author Language：English Publishing type：Research paper (scientific journal)

This study developed logistic regression models to analyse the relationship between 12 observed variables on knowledge, attitudes, and practices toward solid waste management in the suburbs of Phnom Penh city. We interviewed 800 households, including 200 collection service users and 600 non-service users. The determinants of how individuals are aware of, think of, and behave were assessed in the models based on the values of estimated coefficient and probability of t-statistics. As a result, education level and knowledge of health effects have positive influences on knowledge of waste problems. Income is a decisive economic factor of knowledge and attitudes. The residents seem dissatisfied with the status of waste management and collection service if they are aware of the problems. The administration, therefore, needs improvements to satisfy the knowledgeable citizens. Service provision to the non-service users is imperative to halt the practice of illegal dumping. However, the infrequent collection still leads to the improper practice of the service users. We suggest that the service is provided widely, efficiently, and regularly.

DOI： 10.1177/0734242X/18790800

Municipal solid waste management: Constraints and opportunities to improve capacity of local government authorities of Phnom Penh Capital Reviewed

Vin Spoann, Takeshi Fujiwara, Bandith Seng, Chanthy Lay

Waste Management and Research 36 ( 10 ) 985 - 992 2018

Authorship：Last author Language：English Publishing type：Research paper (scientific journal)

Solid waste management is a challenge for Phnom Penh city owing to the increasing volume of waste produced and insufficient collection capacity. Sustainable management is required in response to continuing population growth and urbanisation. This article aims to examine the status and constraints of solid waste management in Phnom Penh and discuss the performance of local government authorities to propose possible mechanisms and strategies to improve the system. Data were collected through literature reviews, key informant interviews and focus group discussions with the local government authorities. Six performance measures were used as assessment variables, including technical, environmental, institutional and organisational, financial and economic, social and cultural, and policy and legal factors. Limited institutional capacity and performance are the consequence of insufficient decentralisation power and allocation of budget and workforce for promoting technological and environmentally sustainable practices. Lack of cooperation and coordination among relevant agencies led to their unwillingness to participate in management performance. A decentralisation and provision of management services in the public–private partnership would enable operational procedures that enhance accountability, transparency, efficiency, and productivity at the local level.

DOI： 10.1177/0734242X18785722

Waste Recycling System for a Tourism City in Vietnam: Situation and Sustainable Strategy Approach - Case Study in Hoi An City, Vietnam Reviewed

S. T.Pham Phu, T. Fujiwara, P. V. Dinh, K. T. Hoa

IOP Conference Series: Earth and Environmental Science 159 ( 159 ) 1 - 8 2018

Authorship：Last author Language：English Publishing type：Research paper (international conference proceedings)

Recycling waste brings many benefits for environment and society so that the establishment of sustainable recycling system is inevitable. This study aims to describe the situation of the recycling system in Hoi An City (HAC), through that establish sustainable recycling strategy for the future. The results show that HAC has a high potential for improving recycling. Whereby, recyclable waste accounts for three-fourths of total waste, and the rate of sorting waste is high. Besides, the proportion of recycling practice is slight high with 62% for residents, 39% for hotel sectors, and 56% for restaurants. However, the recycling system in HAC is simple with the rudimentary facility, in which informal sectors play important roles. Thus, the recycling effectiveness was low (24%), mainly papers, plastics, and metals. The concept of sustainable recycling strategy is established by the combination of the government, community, business sectors toward the balance between economic, environment and society.

DOI： 10.1088/1755-1315/159/012046

Environmental impacts of construction and demolition waste management alternatives Reviewed

Chooi Mei Mah, Takeshi Fujiwara, Chin Siong Ho

Chemical Engineering Transactions 63 343 - 348 2018

Authorship：Last author Language：English Publishing type：Research paper (scientific journal) Publisher：Italian Association of Chemical Engineering - AIDIC

Construction and demolition waste (C&amp
DW) arises mainly as by-products of rapid urbanisation activities. C&amp
DW materials have high potential for recycling and reusing. Despite its potential, landfilling is still the most common disposal method. In Malaysia, C&amp
DW practices are principally guided by economic incentives such as low disposal cost or inexpensive virgin material outweighing recycling cost resulting in low recycling rate. The purpose of this study is to access the environmental impacts caused by landfilling and the alternatives especially in assessing the damages to human health, ecosystems, and to the resources in the future 10 y. It aims to identify the better alternatives in reducing the environmental impacts of landfilling C&amp
DW. Life cycle assessment (LCA) used in this study assessed the environmental impacts associated with all stages, from waste production to end-of-life of waste material. LCA can help to avoid the short-sighted, quick-fix landfilling as the main solution for C&amp
DW by systematically compiling an inventory of energy, fuel, material inputs, and environmental outputs. The environmental impact of landfilling C&amp
DW is estimated to increase 20.2 % if the business as usual (BaU) landfilling continues to the year 2025. Recycling will reduce 46.0 % of total damages and with the shorter travel distance, the environmental damage is further reduced by 82.3 %. Applying industrial building system (IBS) to reduce waste generation at-site reduced 98.1 % impacts as compared to landfilling scenario. The negative impacts derived from landfilling activity is significantly reduced by 99.5 % (scenario 8) through shifting to IBS, recycling, and shorter the travel distance from construction sites to material recycling facilities (MRF). The what-if scenarios illustrated the alternatives future circumstances, the inclusion of the uncertainty concept, and define the future path of C&amp
DW industry outlook. The outcome of this study is informative and useful to policymakers, particularly in defining the way forward of C&amp
DW industry in Malaysia.

DOI： 10.3303/CET1863058

Methodological aspects of modeling household solid waste generation in Japan: Evidence from Okayama and Otsu cities Reviewed

Binxian Gu, Takeshi Fujiwara, Renfu Jia, Ruiyang Duan, Aijun Gu

Waste Management and Research 35 ( 12 ) 1237 - 1246 2017.12

Language：English Publishing type：Research paper (scientific journal)

This paper presents a quantitative methodology and two empirical case studies in Japan on modeling household solid waste (HSW) generation based on individual consumption expenditure (ICE) and local waste policy effects by using the coupled estimation model systems. Results indicate that ICE on food, miscellaneous commodities and services, as well as education, cultural, and recreation services are mainly associated with the changes of HSW generation and its components in Okayama and Otsu from 1980 to 2014. The effects of waste policy measures were also identified. HSW generation in Okayama will increase from 11.60 million tons (mt) in 1980 to 25.02 mt in 2025, and the corresponding figures are 6.82 mt (in 1980) and 14.00 mt (in 2025) in Otsu. To better manage local HSW, several possible and appropriate implications such as promoting a green lifestyle, extending producer responsibility, intensifying recycling and source separation, generalizing composting, and establishing flexible measures and sustainable policies should be adopted. Results of this study would facilitate consumer management of low waste generation and support an effective HSW policy design in the two case cities. Success could lead to emulation by other Japanese cities seeking to build and maintain a sustainable, eco-friendly society. Moreover, the methodologies of establishing coupled estimation model systems could be extended to China and other global cities.

DOI： 10.1177/0734242X17738338

Towards low carbon society in Iskandar Malaysia: Implementation and feasibility of community organic waste composting Reviewed

Cassendra Phun-Chien Bong, Rebecca Kar Yee Goh, Jeng-Shiun Lim, Wai Shin Ho, Chew-Tin Lee, Haslenda Hashim, Nur Naha Abu Mansor, Chin Siong Ho, Abdul Rahim Ramli, Fujiwara Takeshi

JOURNAL OF ENVIRONMENTAL MANAGEMENT 203 ( 2 ) 679 - 687 2017.12

Language：English Publishing type：Research paper (scientific journal) Publisher：ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD

Rapid population growth and urbanisation have generated large amount of municipal solid waste (MSW) in many cities. Up to 40-60% of Malaysia's MSW is reported to be food waste where such waste is highly putrescible and can cause bad odour and public health issue if its disposal is delayed. In this study, the implementation of community composting in a village within Iskandar Malaysia is presented as a case study to showcase effective MSW management and mitigation of GHG emission. The selected village, Felda Taib Andak (FTA), is located within a palm oil plantation and a crude palm oil processing mill. This project showcases a community-composting prototype to compost food and oil palm wastes into high quality compost. The objective of this article is to highlight the economic and environment impacts of a community-based composting project to the key stakeholders in the community, including residents, oil palm plantation owners and palm oil mill operators by comparing three different scenarios, through a life cycle approach, in terms of the greenhouse gas emission and cost benefit analysis. First scenario is the baseline case, where all the domestic waste is sent to landfill site. In the second scenario, a small-scale centralised composting project was implemented. In the third scenario, the data obtained from Scenario 2 was used to do a projection on the GHG emission and costing analysis for a pilot-scale centralised composting plant. The study showed a reduction potential of 71.64% on GHG emission through the diversion of food waste from landfill, compost utilisation and significant revenue from the compost sale in Scenario 3. This thus provided better insight into the feasibility and desirability in implementing a pilot-scale centralised composting plant for a sub-urban community in Malaysia to achieve a low carbon and self-sustainable society, in terms of environment and economic aspects. (C) 2016 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.jenvman.2016.05.033

Life cycle assessment of biodiesel fuel production from waste cooking oil in Okayama City Reviewed

Jinmei Yang, Takeshi Fujiwara, Qijin Geng

JOURNAL OF MATERIAL CYCLES AND WASTE MANAGEMENT 19 ( 4 ) 1457 - 1467 2017.10

Language：English Publishing type：Research paper (scientific journal) Publisher：SPRINGER

A life cycle assessment (LCA) is performed to make clear of the actual environment impacts from conversation of waste cooking oil (WCO) to biodiesel fuel (BDF) in Okayama. A scenario analysis is carried out based on different participation rate of residents who separate WCO from general waste, corresponding to different BDF utilisation rate in transportation system. Sub scenarios complying with different gas emission standards regarding vehicles are designed as well. Afterwards, life cycle impact assessment is conducted to focus on global warming, acidification, and urban air pollution. Overall improvement of almost all kinds of life cycle inventories is significant when diesel is replaced with BDF, demonstrating that a shift from WCO-to-incineration to WCO-to-BDF is more beneficial. Under carbon neutral, compared to base scenario (S0), about 746.05 ton CO2 emission will be reduced annually in the scenario with 100 % BDF utilisation in vehicles (S4). Meanwhile, total external cost in three environmental impacts (EI) sharply reduces by 51.90 %, showing much economic sustainability in S4. Moreover, the manufacturing cost for producing one litter WCO-to-BDF is 97.32 Yen. Sensitivity analysis shows that the gas emission standard regarding vehicles had much bigger effect on EI than BDF manufacturing process in this research.

DOI： 10.1007/s10163-016-0540-x

Predicting waste generation using Bayesian model averaging Reviewed

M. G. Hoang, T. Fujiwara, S. T. Pham Phu, K. T. Nguyen Thi

Global Journal of Environmental Science and Management 3 ( 4 ) 385 - 402 2017.9

Authorship：Last author Language：English Publishing type：Research paper (scientific journal)

A prognosis model has been developed for solid waste generation from households in Hoi An City, a famous tourist city in Viet Nam. Waste sampling, followed by a questionnaire survey, was carried out to gather data. The Bayesian model average method was used to identify factors significantly associated with waste generation. Multivariate linear regression analysis was then applied to evaluate the impacts of significant factors on household waste production. The model obtained from this study indicated that household location, household size, house area per person, and family economic activity are important determinants of the waste generation rate. The models could explain about 34% of the variation of the per capita daily waste generation rate. Diagnostic tests and model validation results showed that the regression model could provide reliable results of estimated household waste. The study revealed that per capita urban household waste generation is 70-80% higher compared to a rural household. The models also showed that if a family ran a business from home, the household waste generation rate would increase by about 35%. This result provides reliable information for better waste collection and management planning. Two other significant variables (family size and house area per capita) do not contribute much (less than 20%) to waste generation. Variables accounting for household income, presence of a garden, number of rooms in a house, and percentage of members of different ages were proven to be not significant. The study provides a reliable method for estimating household waste generation, providing decision makers useful information for waste management policy development.

DOI： 10.22034/gjesm.2017.03.04.005

MUNICIPAL WASTE GENERATION AND COMPOSITION IN A TOURIST CITY — HOI AN, VIETNAM Reviewed

Minh Giang HOANG, Takeshi FUJIWARA, Song Toan, PHAM PHU

Journal of JSCE 5 ( 1 ) 123 - 132 2017

Commercial Solid Waste Generation and Composition Practice in A Tourism City - Hoi An, Vietnam Reviewed

S. T. Pham Phu, M. G. Hoang, T. Fujiwara

Global Waste Management 2017 (7th International Conference on Solid Waste Management, 2017) 867 - 875 2017

Waste Separation at Source Practice and Recycling Potential of The Hotel Industry in Hoi An Ancient City, Vietnam

Song Toan Pham Phu, Takeshi Fujiwara, Giang Hang Minh

4th International Conference on Final Sink 101 - 102 2017

Study on Waste Treatment/Energy Recovery Systems Featuring Gas Production by Waste Gasification and Reforming Reviewed

鈴木和将, 藤原健史, 川本克也

季刊全国環境研会誌(Web) 42 ( 3 ) 52 - 60 2017

Concrete waste management decision analysis based on life cycle assessment Reviewed

Chooi Mei Mah, Takeshi Fujiwara, Chin Siong Ho

Chemical Engineering Transactions 56 25 - 30 2017

Authorship：Last author Language：English Publishing type：Research paper (scientific journal) Publisher：Italian Association of Chemical Engineering - AIDIC

Malaysia, a developing country has always had a high level of construction activity. While it means economic growth, the waste generated by the construction industry has always posed a problem. Most of the construction waste is made up of concrete. The inert and non-hazardous concrete waste, suffers from weak enforcement provisions and this further escalates it into large scale landfill dumping and illegal dumping. The consequences of improper waste management are potentially alarming. With the rising concerns of waste management and global carbon concentrations, this study aims to evaluate the potential environmental impacts associated with concrete waste materials and to identify the best alternative in managing the concrete waste. A comprehensive life cycle assessment framework is proposed to assess the environmental impacts associated with the upstream and downstream of concrete waste life cycle
from raw material extraction to material processing, distribution to disposal or recycle. This study analysed the life cycle system in three scenarios: Scenario 1 depicts the cradle-To-grave scenario where concrete waste is sent to landfill without treatment and recycling. Scenario 2 and 3 depict the cradle-To-cradle scenarios in which the concrete waste is cyclically recycled into aggregates and reuse as road base material and reuse in recycled aggregate concrete production. With the compilation of a systematic life cycle inventory of relevant energy, fuel, and process emissions as inputs and released carbon emissions as outputs, this study helps in interpreting the environmental impacts of different waste management into a series of quantitative measures for more informed decision making. A construction project case study is modelled and analysed in the life cycle assessment framework to demonstrate the model's applicability. Results from this study suggest that the recycle of concrete waste into aggregates and reuse in recycled aggregate concrete production have the least GHG impact to the environment at 0.094 tCO2. Recycling of concrete waste for road base material emits 0.095 tCO2 and followed by landfilling at 0.139 tCO2. This model intended to be an analysis and decisionmaking tool while embracing sustainable development stewardship.

DOI： 10.3303/CET1756005

Construction and demolition waste generation rates for high-rise buildings in Malaysia Reviewed

Chooi Mei Mah, Takeshi Fujiwara, Chin Siong Ho

WASTE MANAGEMENT & RESEARCH 34 ( 12 ) 1224 - 1230 2016.12

Authorship：Last author Language：English Publishing type：Research paper (scientific journal) Publisher：SAGE PUBLICATIONS LTD

Construction and demolition waste continues to sharply increase in step with the economic growth of less developed countries. Though the construction industry is large, it is composed of small firms with individual waste management practices, often leading to the deleterious environmental outcomes. Quantifying construction and demolition waste generation allows policy makers and stakeholders to understand the true internal and external costs of construction, providing a necessary foundation for waste management planning that may overcome deleterious environmental outcomes and may be both economically and environmentally optimal. This study offers a theoretical method for estimating the construction and demolition project waste generation rate by utilising available data, including waste disposal truck size and number, and waste volume and composition. This method is proposed as a less burdensome and more broadly applicable alternative, in contrast to waste estimation by on-site hand sorting and weighing. The developed method is applied to 11 projects across Malaysia as the case study. This study quantifies waste generation rate and illustrates the construction method in influencing the waste generation rate, estimating that the conventional construction method has a waste generation rate of 9.88 t 100 m(-2), the mixed-construction method has a waste generation rate of 3.29 t 100 m(-2), and demolition projects have a waste generation rate of 104.28 t 100 m(-2).

DOI： 10.1177/0734242X16666944

A systematic approach to projecting industrial solid waste generation by industrial sector in Shanghai Reviewed

Jinmei Yang, Takeshi Fujiwara, Yuzuru Matsuoka, Wei Wang

JOURNAL OF MATERIAL CYCLES AND WASTE MANAGEMENT 18 ( 1 ) 81 - 92 2016.1

Authorship：Last author Language：English Publishing type：Research paper (scientific journal) Publisher：SPRINGER

The increasing volumes of industrial solid wastes (ISW) generated have become a serious issue in Shanghai, China. Knowing the volume of ISW that is to be generated in the future is considered a prerequisite for an effective reduction policy and the successful design of treatment facilities. It has been verified that the prediction of ISW generation has an inherent relationship with industrial restructuring caused by economic growth. This study contributes its efforts to develop a systematic approach involving a regional input-output analysis for the forecasting of ISW generation, taking into account the probable industrial restructuring developments. In the process, changes in the consumption patterns, export structure, and technical change are considered to be the important drivers. Further, a sensitivity analysis is carried out as well to investigate the influence of change in consumption on ISW generation. The case study of Shanghai provides for a feasible application of our model on a regional level until the year 2020.

DOI： 10.1007/s10163-014-0330-2

Feasibility Study on Effectiveness of Solid Waste Incineration in Hoi An, Vietnam

Hoang Minh Giang, Fujiwara Takeshi

1 - 4 2016

A Life cycle assessment framework for evaluatin of construction and demolition waste management practices

Chooi Mei Mah, Takeshi Fujiwara, Chin Siong Ho

Asian-Pacific Landfill Symposium - Integrated Waste Management and Sustainable Landfilling (APLAS 2016) 1 - 7 2016

Municipal Solid Waste Characterization and Waste Management Issues in a Tourist City - Hoi An, Vietnam

Hoang Minh Giang, Fujiwara Takeshi, Pham Phu Song Toan

Asian-Pacific Landfill Symposium - Integrated Waste Management and Sustainable Landfilling (APLAS 2016) 1 - 10 2016

Management of landfill reclamation with regard to biodiversity preservation, global warming mitigation and landfill mining: experiences from the Asia-Pacific region

Yu-Chi Weng, Takeshi Fujiwara, Harvey J. Houng, Chia-Hui Sun, Wen-Ying Li, Ya-Wen Kuo

JOURNAL OF CLEANER PRODUCTION 104 364 - 373 2015.10

Authorship：Last author Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCI LTD

As a comparatively low-cost technology for waste treatment and disposal, landfilling has been adopted worldwide, particularly in developing countries. After one landfill is fully filled, the aftercare management turns into an important issue for municipalities, while the deposited waste is highly complex and condensed. Recent literature has indicated that landfill management plays an important role on critical issues of contemporary solid waste management, including biodiversity preservation, global warming mitigation, landfill mining and land reclamation. This study firstly made a comprehensive literature review on the existing studies in several Asia-Pacific economies, secondly conducted field surveys for the several illustrations of the aftercare management of closed landfills in Japan and Taiwan. Afterward, the findings from the literature and illustrations from the Asia-Pacific region were qualitatively summarized. Based on the results, concrete management strategies were discussed for the aftercare management of closed landfills in the context of land reclamation from important perspectives. For promoting the closed landfill management and seeking for adequate reclamation methods, the ex-post monitoring, impact assessments, and the essential cost-benefit analysis should be implemented with regard to respective reclamation type and local conditions. Using the outcomes of this study, municipalities can formulate concrete strategies to mitigate the risks and negative impacts, and to increase the benefits of landfills from a life-cycle perspective, considering the multi-stakeholders. (C) 2015 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.jclepro.2015.05.014

Municipal solid waste characterization and recycling potentials in Phnom Penh city, Cambodia

Bandith Seng, Takeshi Fujiwara

The 2nd 3R International Scientific Conference on Material Cycle and Waste Management 1 - 4 2015

A Survey of Construction and Demolition Waste in Malaysia Mixed-Use Development

Chooi Mei Mah, Takeshi Fujiwara, Chin Shing Ho

ISWA Beacon 3rd International Conference on Final Sinks 54 - 55 2015

Recycling of plastic packaging waste in Bandung City, Indonesia Reviewed

Mochammad Chaerul, Ahmad Reza Fahruroji, Takeshi Fujiwara

JOURNAL OF MATERIAL CYCLES AND WASTE MANAGEMENT 16 ( 3 ) 509 - 518 2014.7

Language：English Publishing type：Research paper (scientific journal) Publisher：SPRINGER

Economic growth, changing consumption and production patterns are resulting in rapid increase in the generation of plastic wastes, including plastic packaging waste (PPW). A variety of PPW is identified in the municipal solid waste (MSW) stream. In this paper, quantity and composition of PPW at generators (residential and nonresidential sectors) and at the informal sector of waste recycling were measured, and accordingly the flow of PPW within Bandung City, Indonesia was analyzed. Though the generation rate per capita is not so high (25.1 g per day), total PPW generated by 2.3 million inhabitants in Bandung becomes 58.4 tonnes per day (3.76 % of total MSW generated). Due to lack of integrated MSW management, most of PPW is neither collected properly nor disposed of in appropriate manner by the municipality. Collection of valuable wastes including PPW is done predominantly by the informal sector without regard to health and safety. It is predicted that total PPW recycled by various informal waste recycling players like scavengers, junkmen, intermediates, and dealers is 27.5 tonnes per day (64.6 % of total PPW generated). Interviews regarding the existing handling methods and incentives preferred by generators to increase the recycling rate are also presented.

DOI： 10.1007/s10163-013-0201-2

Transforming Municipal Waste into a Valuable Soil Conditioner through Knowledge-Based Resource-Recovery Management Reviewed

Golabi MH, Kirk Johnson, Takeshi Fujiwara, Eri Ito

International Journal of Waste Resources 87 - 100 2014

Prospect of Household Solid Waste Management Improvement based on Low Carbon Society Survey in Iskandar Malaysia

Takeshi Fujiwara, Siti Norbaizura, Md. Rejab, ho Chin Siong, Zainura Zainon Noor

The 3R International Scientific Conference on Material Cycles and Waste Management (3RINCS) and 13th Expert Meeting on Solid Waste Management in Asia and Pacific Island (SWAPI) 1 - 4 2014

A study on system optimization of solid waste management in Johor Bahru, Malaysia

Takeshi Fujiwara, Yasuhito Yoneda

The 8th Asian-Pacific Landfill Symposium (APLAS) in Hanoi 1 - 7 2014

A Study of Commercial Solid Waste Generation and Composition in Phnom Penh City, CAMBODIA Reviewed

YIM Mongtoeun, Takeshi FUJIWARA, SOUR Sethy

Journal of Natural Science Research 4 ( 13 ) 49 - 54 2014

Estimation of Tsunami Disaster Waste Amount and Location Planning of Temporal Stockyard by Map Information Reviewed

藤原健史, 中村彰太

EICA 17 ( 4 ) 2013

Sustainable Waste Management for Low-carbon Society Iskandar Malaysia 2025 Reviewed

Takeshi Fujiwara, Sit Nor Baizura

8th International Symposium on Digital Earth 1 - 7 2013

Characterization and Modeling of Household Waste Generation Based on a Questionnaire Study - Case Study of Iskandar Malaysia Reviewed

Siti Norbaizura M, R, Takeshi Fujiwara, Ho Chin Siong

環境衛生工学研究 27 ( 2 ) 9 - 19 2013

Solid Waste Management strategy Towards A Sound Material Cycle Society in A Low-Carbon Society - Iskandar Malaysia

Takeshi Fujiwara, Sti Norbaizura

International Conference on Waste Management and Environment (ICWME 2013) 1 - 4 2013

Study on waste reduction possibility through alternative Scenarios of treatment facilities in Hanoi base on Life Cycle Assessment

Luong Tie, Mai Huong, Takeshi Fujiwara, Nguyen Thi Kim Thai

International Conference on Waste Management and Environment (ICWME 2013) 1 - 4 2013

AN ASSESSMENT ON HOUSEHOLD ATTITUDES AND BEHAVIOR TOWARDS HOUSEHOLD SOLID WASTE DISCARD AND RECYCLING IN THE MEKONG DELTA REGION - SOUTHERN VIETNAM Reviewed

Nguyen Phuc Thanh, Yasuhiro Matsui, Takeshi Fujiwara

ENVIRONMENTAL ENGINEERING AND MANAGEMENT JOURNAL 11 ( 8 ) 1445 - 1454 2012.8

Language：English Publishing type：Research paper (scientific journal) Publisher：GH ASACHI TECHNICAL UNIV IASI

The aims of this study were to explore and assess the household behavior towards recyclable waste discard and household attitudes towards good waste management in the Mekong delta region - southern Vietnam. A questionnaire survey was carried out in 100 households in Can Tho city. The existing household habits for waste discard, storage, collection, and recycling activities were clarified in order to identify the priority problems of these activities. Regarding household behavior towards recycling activities and the purchase behavior of households for avoidable wastes (e.g., plastic carry bags, container and packaging, expired/residual food waste) were explored. The household behavior for reusing the used valuable things instead of discarding and for consuming the products or goods made from recycling materials was also examined. Besides, household attitudes towards good waste management were partly explored; the results found that the neighbor's view and social norms seemed to work for keeping order in waste collection and discard activities. Moreover, the authors also analyzed the interrelationships among the household behavior towards recycling activities, the household attitudes towards good waste management, and individual attributes such as the education level, urbanization level, income, age, gender, and working status. It was found that household attitudes towards good waste management correlated to household behavior towards recycling activities; education level and urbanization level were identified as relevant factors for enhancing waste recycling activities and good environmental attitudes of households.

DOI： 10.30638/eemj.2012.180

Future Projection of Solid Waste Discharge in Island Country with Tourism as Main Industry - Case Study on Guam -

Fujiwara Takeshi, ITO ERI

Proceedings of the Annual Conference of Japan Society of Material Cycles and Waste Management 23 81 - 81 2012

Publisher：Japan Society of Material Cycles and Waste Management

Guam island of US accepts about 1.1 million tourists every year comparing topopulation  160,000, and over 80% of tourists is Japanese.  While a tourist stays in the island, many goods used by the tourist become solid waste and also other waste is indirectly generated in the process of supplying the goods or services.  On the other hand, residents in Guam, mainly aboriginal Chamorro, have accepted modern consumption style that people buy commodities in a supermarket and eat in a restaurant, thus, the amount of waste discharge has increased.  Due to less resources and small number of industries except tourism, Guam island has to import many goods from oversea.  In this study, it is assumed that the amount of waste discharge depends on consumption behaviors of household, government and tourists, and economics of Guam is supported by tourist’s expense.  Based on the assumptions, future waste discharge from household until 2020 is projected through developing IO table, future prediction of population, and future scenario of population and tourism.

DOI： 10.14912/jsmcwm.23.0_81

Development of Temporal Stock Yard Selection System for Flood Disaster Waste

Fujiwara Takeshi, Nakamura Syouta

Proceedings of the Annual Conference of Japan Society of Material Cycles and Waste Management 23 193 - 193 2012

Publisher：Japan Society of Material Cycles and Waste Management

The amount of disaster waste caused by the Great East Japan Earthquake in March 11th, 2011 was estimated at 22 million tons in Iwate, Miyagi and Fukushima prefectures. For the sake of keeping and sorting a massive disaster waste, it needs many temporal storage yards according to the amount. Estimating the amount of disaster waste as soon as possible is useful for planning on restoration and reconstruction. In this study, we propose a method to estimate the amount of disaster waste by getting map information of buildings in the stricken area.  Moreover, evaluation method to find better locations and suitable for temporal storage yard by considering both the estimated amount of waste and the distance between disaster area and temporal storage yard is proposed and support system is developed.

DOI： 10.14912/jsmcwm.23.0_193

Development of Measurement Method for Pileup Rubble Waste by Using Silhouette Volume Intersection Reviewed

藤原健史

EICA 17 ( 2/3 ) 2012

産業連関表を用いたグアムにおける家庭ごみ排出量の将来推計-人口増加及び観光業の影響分析- Reviewed

藤原健史, 伊藤依理

地球環境研究論文集 20 2012

Examining the effectiveness of municipal solid waste management systems: An integrated cost-benefit analysis perspective with a financial cost modeling in Taiwan Reviewed

Yu-Chi Weng, Takeshi Fujiwara

WASTE MANAGEMENT 31 ( 6 ) 1393 - 1406 2011.6

Authorship：Last author Language：English Publishing type：Research paper (scientific journal) Publisher：PERGAMON-ELSEVIER SCIENCE LTD

In order to develop a sound material-cycle society, cost-effective municipal solid waste (MSW) management systems are required for the municipalities in the context of the integrated accounting system for MSW management. Firstly, this paper attempts to establish an integrated cost-benefit analysis (CBA) framework for evaluating the effectiveness of MSW management systems. In this paper, detailed cost/benefit items due to waste problems are particularly clarified. The stakeholders of MSW management systems, including the decision-makers of the municipalities and the citizens, are expected to reconsider the waste problems in depth and thus take wise actions with the aid of the proposed CBA framework. Secondly, focusing on the financial cost, this study develops a generalized methodology to evaluate the financial cost-effectiveness of MSW management systems, simultaneously considering the treatment technological levels and policy effects. The impacts of the influencing factors on the annual total and average financial MSW operation and maintenance (O&M) costs are analyzed in the Taiwanese case study with a demonstrative short-term future projection of the financial costs under scenario analysis. The established methodology would contribute to the evaluation of the current policy measures and to the modification of the policy design for the municipalities. Crown Copyright (C) 2011 Published by Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.wasman.2011.01.016

Assessment of plastic waste generation and its potential recycling of household solid waste in Can Tho City, Vietnam Reviewed

Nguyen Phuc Thanh, Yasuhiro Matsui, Takeshi Fujiwara

ENVIRONMENTAL MONITORING AND ASSESSMENT 175 ( 1-4 ) 23 - 35 2011.4

Language：English Publishing type：Research paper (scientific journal) Publisher：SPRINGER

Plastic solid waste has become a serious problem when considering the disposal alternatives following the sequential hierarchy of sound solid waste management. This study was undertaken to assess the quantity and composition of household solid waste, especially plastic waste to identify opportunities for waste recycling. A 1-month survey of 130 households was carried out in Can Tho City, the capital city of the Mekong Delta region in southern Vietnam. Household solid waste was collected from each household and classified into ten physical categories; especially plastic waste was sorted into 22 subcategories. The average household solid waste generation rate was 281.27 g/cap/day. The compostable and recyclable shares respectively accounted for high percentage as 80.74% and 11%. Regarding plastic waste, the average plastic waste generation rate was 17.24 g/cap/day; plastic packaging and plastic containers dominated with the high percentage, 95.64% of plastic waste. Plastic shopping bags were especially identified as the major component, accounting for 45.72% of total plastic waste. Relevant factors such as household income and household size were found to have an existing correlation to plastic waste generation in detailed composition. The household habits and behaviors of plastic waste discharge and the aspects of environmental impacts and resource consumption for plastic waste disposal alternatives were also evaluated.

DOI： 10.1007/s10661-010-1490-8

Evaluation of Waste Treatment Strategies in Chinese cities from View points of GHG Emission Reviewed

Jinmei YANG, Takeshi FUJIWARA, Yuzuru MATSUOKA, Wei WANG

Journal of Environmental Science for Sustainable Society 5 27 - 36 2011

Language：English Publishing type：Research paper (scientific journal) Publisher：Graduate School of Environmental and Life Science, Okayama University

Recent years have witnessed increased attention being given to the evaluation and selection of alternative waste treatment strategies from the view of reduction of greenhouse gas (GHG) emissions. However, a long period of waste records is necessary for getting acceptably accurate results, especially in calculating GHG emission from disposal site. Therefore, in this paper, applying the systematic approach we have developed in the previous work, the back-casting and ex-post forecasting of the waste quantity by composition in the past is conducted. Then, current GHG emissions in five Chinese metropolitan cities are investigated and analyzed; thereafter, a scenario analysis is carried out in Shanghai based on the forecasts of waste generation and the corresponding waste category in 2015. Methane (CH₄), carbon dioxide (CO₂) and nitrous oxide (N₂O) are mainly taken into account in GHG emission due to significant amount emitted from waste treatment. The results confirm that the per capita CO₂ emission factor (kg CO₂-eq/kg waste-treated) in Shanghai, Guangzhou, Hangzhou, Wuhan and Chengdu in 2007 is 0.48, 0.59, 0.57, 0.41 and 0.48 respectively, thereby demonstrating that economic growth is the main driving force of GHG emissions currently observed in Chinese cities. Further, through the scenario analysis, composting and integrated waste management are considered as effective attempts at reducing GHG emissions in Shanghai.

DOI： 10.3107/jesss.5.27

Household solid waste generation and characteristic in a Mekong Delta city, Vietnam Reviewed

Nguyen Phuc Thanh, Yasuhiro Matsui, Takeshi Fujiwara

JOURNAL OF ENVIRONMENTAL MANAGEMENT 91 ( 11 ) 2307 - 2321 2010.11

Language：English Publishing type：Research paper (scientific journal) Publisher：ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD

This study was undertaken to evaluate the quantity and composition of household solid waste to identify opportunities for waste recycling in Can Tho city, the capital city of the Mekong Delta region in southern Vietnam. Two-stage survey of 100 households was conducted for dry season and rainy season in 2009. Household solid waste was collected from each household and classified into 10 physical categories and 83 subcategories. The average household solid waste generation rate was 285.28 g per capita per day. The compostable and recyclable shares respectively accounted for 80.02% and 11.73%. The authors also analyzed the relations between some socioeconomic factors and household solid waste generation rates by physical categories and subcategories. The household solid waste generation rate per capita per day was positively correlated with the population density and urbanization level, although it was negatively correlated with the household size. The authors also developed mathematical models of correlations between the waste generation rates of main physical categories and relevant factors, such as household size and household income. The models were proposed by linear models with three variables to predict household solid waste generation of total waste, food waste, and plastic waste. It was shown that these correlations were weak and a relationship among variables existed. Comparisons of waste generation by physical compositions associated with different factors, such as seasonal and daily variation were conducted. Results presented that the significant average differences were found by the different seasons and by the different days in a week; although these correlations were weak. The greenhouse gas baseline emission was also calculated as 292.25 g (CO2 eq.) per capita per day from biodegradable components. (C) 2010 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.jenvman.2010.06.016

Application of Advanced Municipal Solid Waste Furnace Feeding System Using Stereo Image Processing System to a Real Plant

TAKAOKA Masaki, ITOH Daisuke, NAKATSUKA Daisuke, KAKUTA Yoshitada, TAKEDA Nobuo, FUJIWARA Takeshi, OSHITA Kazuyuki

EICA 15 ( 2 ) 221 - 224 2010.10

An analysis of municipal solid waste discards in Taiwan based on consumption expenditure and policy interventions Reviewed

Yu-Chi Weng, Takeshi Fujiwara, Yuzuru Matsuoka

WASTE MANAGEMENT & RESEARCH 28 ( 3 ) 245 - 255 2010.3

Authorship：Last author Language：English Publishing type：Research paper (scientific journal) Publisher：SAGE PUBLICATIONS LTD

This paper presents a quantitative methodology and an empirical case study in Taiwan on modelling municipal solid waste (MSW) discards based on the consumption and MSW policy effects through a simultaneous equation system (SES) model. The results indicate that per capita consumption expenditures on 'food', 'household appliances' and 'amusement & education' are associated with the changes of the discards of most of the waste streams in Taiwan from 1992 to 2004. The developed model, meanwhile, identifies the effects of several important MSW policy measures. With regard to the model implication, consumers could try to reduce their unnecessary consumption, producers may rethink their responsibility on reducing MSW discards, and municipalities could evaluate the effectiveness of the existing policy measures to improve it upon based on the quantitative analysis. The backcasts and estimates of the discards of MSW streams could enable the planning, designing and executing of MSW system. The findings of this study would facilitate the consumer behaviour and support the policy design towards a low-waste-discard society.

DOI： 10.1177/0734242X09343305

Application of a MSW generation estimation model: A comparison of generation property among metropolitan cities in China Reviewed

Jinmei Yang, Takeshi Fujiwara, Yuzuru Matsuoka, Wei Wang

Journal of Global Environment Engineering 15 1 - 14 2010.2

Authorship：Last author Language：English Publishing type：Research paper (scientific journal)

This paper applies an integrated model to estimate the generation of municipal solid waste (MSW) by composition, taking into account the consumption expenditure by category and waste management policies. Five Chinese metropolises with different economic levels are selected for model application and comparison. In each selected city, firstly, a household consumption pattern is estimated using an extension of the linear expenditure system (LES), with lifestyle of residents attributed as explanatory variables; thereafter, MSW generation by composition is quantitatively expressed in terms of expenditure for consumption category and the waste policies by using ordinary least squares (OLS). The research findings clearly indicate that the integrated model is validated in each city with good performance of model testing. Further, the range of convention efficiency from consumption to each type of waste is determined. Moreover, the average unit MSW generation per consumption expenditure is 0.213 kg/RMB. In addition, the waste measures undertaken by the local governments have different influences on MSW generation. Accordingly, the model not only has the ability to predict the generation of each type of waste, but also presents a possibility of application to other Chinese cities without sufficient waste statistics.

Study on Image Processing of Refuse Dumping in the Pit of Refuse Incinerator Plant Reviewed

FUJIWARA Takeshi, YOSHIKAWA Kaori, LIU Dawei, TSUJIMOTO Shinichi, MATSUDA Yoshiji

EICA 14 ( 2 ) 110 - 114 2009.10

The Effects of Heating Time and Temperature on de novo Synthesis of PCBs and CBzs in Fly Ash by Particle Size Reviewed

TAKAOKA Masaki, TANIGAKI Nobuhiro, TAKEDA Nobuo, FUJIWARA Takeshi

Journal of the Japan Society of Waste Management Experts 17 ( 1 ) 11 - 22 2006.1

Development of an Advanced Municipal Solid Waste Furnace Feeding Model and its Application Reviewed

ITOH Daisuke, TAKAOKA Masaki, NAKATSUKA Daisuke, KAKUTA Yoshitada, TAKEDA Nobuo, FUJIWARA Takeshi, OSHITA Kazuyuki

Journal of the Japan Society of Waste Management Experts 16 ( 3 ) 189 - 197 2005.5

Volume Measurement of Municipal Solid Waste in a Hopper Using the Stereo Image Processing Technique Reviewed

伊藤大輔, 高岡昌輝, 中塚大輔, 角田芳忠, 武田信生, 藤原健史, 大下和徹

廃棄物学会論文誌 16 ( 5 ) 2005

A STUDY ON SOLID WASTE GENERATION OF ASIAN COUNTRY USING REPORTED WASTE GENERATION DATA AND INDUSTRIAL STATISTIC Reviewed

Tsutomu Sasaki, Yuzuru Matsuoka, Takeshi Fujiwara

Environmental Systems Research 33 2005

Re-synthesis Mechanisms for PCBs and Chlorobenzenes in Fly Ash by Particle Size Reviewed

TAKAOKA Masaki, TANIGAKI Nobuhiro, TAKEDA Nobuo, FUJIWARA Takeshi

Journal of the Japan Society of Waste Management Experts 15 ( 5 ) 336 - 346 2004.9

Language：Japanese Publisher：Japan Society of Material Cycles and Waste Management

We focused on separating fly ash by particle size in order obtain fractions with different compositions. We then conducted heating experiments on each fraction under a variety of temperature and atmospheric conditions in order to understand the re-synthesis mechanisms of chlorinated aromatics in fly ash and the distributions of PCBs and chlorobenzenes (CBzs) by fly ash particle size. As a result, we found that the contributions of metal catalysts and unburned carbon in the formation of PCBs and CBzs were dependent on heating temperature. The homologue patterns of PCBs and CBzs were almost the same in all fractions of fly ash in the heating experiments. This indicates that all fractions of fly ash had the same formation patterns. The effect of atmosphere on the formation of chlorinated aromatics showed no difference among the fractions. HCl in a nitrogen atmosphere with 10% oxygen did not promote generation of PCBs and CBzs in fly ash. We confirmed that metal chlorides in fly ash were important as a chlorine source rather than HCl gas for the formation of chlorinated aromatics in fly ash.

DOI： 10.3985/jswme.15.336

A STUDY OF A RECONCILIATION MODEL OF MATERIAL FLOW AND STOCK ACCOUNTS WITH ECONOMIC AND INDUSTRIAL STATISTICS Reviewed

Taiyo Nakamura, Yuzuru Matsuoka, Takeshi Fujiwara

Environmental Systems Research 32 2004

The behavior of PCDD/Fs, PCBs, chlorobenzenes and chlorophenols in wet scrubbing system of municipal solid waste incinerator Reviewed

Masaki Takaoka, Peiyu Liao, Nobuo Takeda, Takeshi Fujiwara, Kazuyuki Oshita

Chemosphere 53 ( 2 ) 153 - 161 2003.10

Language：English Publishing type：Research paper (scientific journal)

Though some researchers have already reported polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) concentration in flue gas at inlet and outlet of wet scrubber (WS) in municipal solid waste incinerator (MSWI), there are few investigations about scrubbing water, suspended solid (SS) in scrubbing water and sludge. In order to understand the behavior of PCDD/Fs in WS and to make clear the effect of the residence time of scrubbing water in WS on the PCDD/Fs concentrations in scrubbing water and at the outlet gas of WS, PCDD/Fs, polychlorinated biphenyls (PCBs), chlorobenzenes (CBzs) and chlorophenols (CPs) concentrations in various media around WS were investigated at two MSWIs. PCDD/Fs concentration in flue gas at outlet of WS was higher than that at inlet of WS in both MSWIs. In WS A, it was observed that the homologue profiles changed considerably and the concentration of higher chlorinated compounds such as H7CDD/Fs and O8CDD/F increased remarkably at outlet gas of WS A. Only CPs were transferred from flue gas to scrubbing water in both WSs. As for scrubbing water, a large amount of their chlorinated aromatic compounds was detected in SS particles. According to the results, it was found that not only flue gas conditions but also operational and structural conditions in WS had great influence on minimizing the memory of chlorinated aromatic compounds in WS. © 2003 Elsevier Ltd. All rights reserved.

DOI： 10.1016/S0045-6535(03)00437-5

Developmental Study of MSW Feed Rate Stabilization System for Stoker-Type MSW Incinerators : Lower Heating Value Presumption and Compaction Characteristic of MSW Reviewed

KAKUTA Yoshitada, NAKATSUKA Daisuke, ITO Daisuke, TAKEDA Nobuo, FUJIWARA Takeshi, TAKAOKA Masaki

Journal of the Japan Society of Waste Management Experts 14 ( 4 ) 210 - 218 2003.7

Language：Japanese Publisher：Japan Society of Material Cycles and Waste Management

The relationship between the bulky density of MSW and its lower heating value was clarified as part of research for the establishment of the MSW feed rate stabilization system in stoker-type MSW incinerator. The compaction characteristic of MSW was also examined through experimentation with artificial MSW.<BR>A strong correlation was admitted to exist between bulky density and the lower heating value of MSW. The presumption of the lower heating value became possible by measuring bulky density, although population and regional difference played an influential role in the bulky density concept.<BR>There was great volume change for MSW in the feed part, and this became crucial when considering the compaction of MSW for the presumption of the MSW feed rate. The compaction characteristic curve obtained by the experiment consisted of the part expressed in the second approximation evaluation and in the first approximation equation. Though the curves depended on the composition of the MSW and/or the compaction experimental method, their shapes were basically similar.

DOI： 10.3985/jswme.14.210

ESTIMATION OF HEMISPHERE TEMPERATURE OF ASH USING THE COMPOSITION AND DIFFERENTIAL THERMAL ANALYSIS DATA Reviewed

TAKAOKA Masaki, FUJITA Jun, FUJIWARA Takeshi, TAKEDA Nobuo

土木学会論文集 727 ( 727 ) 91 - 101 2003.2

CLASSIFICATION OF FUSION PATTERNS OF BOTTOM ASH AND FLY ASH USING DIFFERENTIAL THERMAL ANALISIS Reviewed

TAKAOKA Masaki, FUJIWARA Takeshi, FUJITA Jun, TAKEDA Nobuo

土木学会論文集 727 ( 727 ) 77 - 89 2003.2

A Study on the Scale of Waste Centralized Treatment from the viewpoints of Environmental Impacts, Traffic Loads and Total Cost Reviewed

Tsutomu Sasaki, Takeshi Fujiwara, Yuzuru Matsuoka

Environmental Systems Research 31 2003

Control of mercury emissions from a municipal solid waste incinerator in japan Reviewed

Masaki Takaoka, Nobuo Takeda, Fujiwara Takeshi, Masato Kurata, Kimura Tetsuo

Journal of the Air and Waste Management Association 52 ( 8 ) 931 - 940 2002.8

Language：English Publishing type：Research paper (scientific journal)

The control of Hg emissions from a municipal solid waste incinerator (MSWI) is very important, because more than 78% of municipal solid waste (MSW) is incinerated. The Hg content of coal used in utility boilers is relatively low in Japan. In this study, recent trends in the Hg content of MSW in Japan and activated carbon (AC) injection as a control technology of Hg emission from an MSWI are discussed.The effect of AC injection on Hg removal from flue gas in an MSWI was investigated by pilot-scale experiments using a bag filter (BF). The injection of AC increases the Hg reduction ratio by 20–30% compared with cases without AC injection. The Hg reduction ratio increases as the flue gastemperature decreases. The Hg reduction ratio is closely related to the inlet Hg concentration and was expressed with a Langmuir-type adsorption isotherm. © 2002 Air & Waste Management Association.

DOI： 10.1080/10473289.2002.10470831

Feasibility Study on Heavy Metals Recovery from Fly Ash of Ash Melting Furnace by Utilizing Existing Production Facilities as Social Resources Reviewed

FUJIWARA Takeshi, TAKEDA Nobuo, NAKAHARA Keisuke, AKASHI Tetsuo, TSURUI Minoru, NAGASAKI Hidenori

Energy and resources 23 ( 1 ) 55 - 60 2002.1

A model on household waste generation and goods preference. Reviewed

Takeshi Fujiwara, Tomohiro Ueno, Yuzuru Matsuoka

Environmental Systems Research 30 2002

Modeling on Emission of Domestic Waste Considering Flow and Stock of Consumer Goods. Reviewed

Yuko Kanamori, Takeshi Fujiwara, Yuzuru Matsuoka

Environmental Systems Research 30 2002

A Study on Production of Gaseous Components from Batch Combustion of Plastics Waste. Reviewed

Norikazu Iwata, Takeshi Fujiwara, Nobuo Takeda, Masaki Takaoka, Syoji Eguchi

Environmental Engineering Research 39 2002

Surface Shape Measurement of Waste Stacked on Hopper in Municipal Refuse Incinerator by Using Stereo Image Processing Reviewed

ITO DAISUKE, FUJIWARA TAKESHI, TAKEDA NOBUO, TAKAOKA MASAKI, KAKUTA HIDETADA, NAKATSUKA DAISUKE

EICA 6 ( 1 ) 37 - 43 2001.9

EXPERIMENTAL STUDY ON INHIBITION OF CHLORINATED AROMATICS FORMATION ON FLYASH USING SODIUM SULFIDE Reviewed

TAKAOKA Masaki, NAKAMORI Ken-ichi, TAKEDA Nobuo, FUJIWARA Takeshi

Proceedings of JSCE 685 ( 685 ) 91 - 102 2001.8

Language：Japanese Publisher：Japan Society of Civil Engineers

The effect of sodium sulfide (Na₂S) on the formation of chloribnated aromatics such as polychlorinated biphenyls (PCBs) and chlorobenzenes (CBz) in post combusiton zone (200-500°C) of municipal solid waste incinerator was investigated. When fly ash was heated with mixture of 2% Na₂S at the condition of 300°C and 30min in air with 500ppm hydrogen chloride, total levels of CBz and PCBs decreased by 49% and 22% compared with that of fly ash without addition of Na₂S, respectively. The analysis using the sequential chemical extraction method indicated copper compounds in fly ash changed into copper sulfide. The main inhibiting mechanism was estimated to be the reduction of catalytic activity of fly ash.

DOI： 10.2208/jscej.2001.685_91

ANAEROBIC DIGESTION OF SEWAGE SLUDGE FROM PRE-COAGULATION Reviewed

TAKAOKA Masaki, HIROTA Junichi, TAKEDA Nobuo, FUJIWARA Takeshi

Proceedings of JSCE 685 ( 685 ) 17 - 26 2001.8

ESTIMATION OF SPIECIES OF ZINC, LEAD, COPPER AND CADMIUM IN FLY ASH BY A SEQUENCIAL CHEMICAL EXTRACTION METHOD Reviewed

TAKAOKA Masaki, KURAMOTO Yasuhiro, TAKEDA Nobuo, FUJIWARA Takeshi

Proceedings of JSCE 685 ( 685 ) 79 - 90 2001.8

X-ray photoelectron spectroscopy analysis for a reaction on the surface of tin metal in a continuous mercury analyzer Reviewed

TAKAOKA Masaki, SHIMAOKA Yutaka, TAKEDA Nobuo, FUJIWARA Takeshi

BUNSEKI KAGAKU 50 ( 7 ) 501 - 507 2001.7

Language：Japanese Publisher：The Japan Society for Analytical Chemistry

In order to understand the reaction in a continuous mercury analyzer with the dry-type reduction process, the surface of granular tin metal in a dry-type reduction process was characterized by X-ray photoelectron spectroscopy (XPS). First, the method for chlorinating the surface of tin metal was investigated. It was found that the surface of tin metal was more deeply chlorinated by impregnating with 1 mol/l hydrochloric acid for 2 hours than by passing 600 ppm hydrochloric acid gas through the reactor for the number of same hours. Subsequently, the change on the surface of granular tin metal by impregnating with 1 mol/l hydrochloric acid was observed in the case of passing air with mercury (II) chloride gas and moisture through the reactor. Tin (II) chloride on tin metal changed into tin (II, IV) oxide upon exposure to air or moisture. Depth profiles indicated that a tin (IV) oxide layer was formed on a tin (II) oxide layer. These results suggested that the reducibility of tin metal depended on the ratio of the chlorinated surface. As for the reaction on the surface of tin metal pre-coated with 1 mol/l hydrochloric acid, the resulting X-ray photoelectron spectra were in good agreement with the reaction estimated from the mass balance in the actual experiment.

DOI： 10.2116/bunsekikagaku.50.501

Other Link： http://dl.ndl.go.jp/info:ndljp/pid/10895046

Speciation of Zinc, Lead and Copper on Fly Ash by X-ray Photoelectron Spectroscopy Reviewed

TAKAOKA Masaki, KURAMOTO Yasuhiro, TAKEDA Nobuo, FUJIWARA Takeshi

Journal of the Japan Society of Waste Management Experts 12 ( 3 ) 102 - 111 2001.5

Language：Japanese Publisher：Japan Society of Material Cycles and Waste Management

It is very important to know the dominant forms of heavy metals in fly ash generated from municipal solid waste incinerators or ash melting plants for consideration of detoxification and recycling. In this study, zinc, lead and copper in fly ash sampled in twenty municipal solid waste incinerators and five ash melting plants were analyzed using X-ray photoelectron spectroscopy. The dominant zinc compounds were 2ZnCO₃⋅3Zn (OH) ₂on the surface of fly ash and Zn or ZnO within the fly ash. PbCO₃and/or PbCl₂on the surface of fly ash were estimated. The chemical forms of copper did not depend on the fly ash type or depth and CuCl₂was not detected. Zinc and lead are therefore predominantly concentrated on the surface of fly ash.

DOI： 10.3985/jswme.12.102

Recovery of Phosphate and Ferric Chloride from Pre-Coagulated Sludge with Ferric Chloride. Reviewed

Masaki Takaoka, Jyunichi HIrota, Nobuo Takeda, Takeshi Fujiwara

Environmental Engineering Research 38 2001

Measures to prevent emissions of PCDDS/DFs and co-planar PCBs from crematories in Japan Reviewed

Nobuo Takeda, Masaki Takaoka, Takeshi Fujiwara, Hisayuki Takeyama, Shoji Eguchi

Chemosphere 43 ( 4-7 ) 763 - 771 2001

Language：English Publishing type：Research paper (scientific journal)

In this study, PCDDs/DFs and co-planar PCBs concentrations in flue gases from 17 crematories and in fly ashes and bottom ashes (mainly bone) from several crematories were measured to grasp the present state of PCDDs/DFs emissions from crematories. The effects of several factors were discussed to prevent PCDDs/DFs emissions from crematories. Total concentration (normalized by 12% O2) of PCDDs/DFs was ranged from 4.9 to 1200 ng/m3 N, and toxic equivalent concentration was ranged from 0.064 to 24 ng TEQ/m3 N. As the results obtained in this research, the following measures to reduce PCDDs/DFs emission are recommended for existing crematories: (1) keeping the temperature at 800°C in main/secondary chambers during a whole cremation, and (2) lowering the temperature in the dust collector. For newly installed crematories, following measures to prevent PCDDs/DFs emission including the measures for existing ones are recommended: (1) connecting one secondary chamber to one main chamber, (2) installing the high efficiency dust collector and reducing dust concentration to less than 0.01 g/m3 N, and (3) installing the sampling point for monitoring of PCDDs/DFs. © 2001 Elsevier Science Ltd.

DOI： 10.1016/S0045-6535(00)00431-8

Study on Continuous Mercury Analyzer with Dry-type Reduction Process for Flue Gas Reviewed

TAKAOKA Masaki, SHIMAOKA Yutaka, HOSHINO Munehiro, TAKEDA Nobuo, FUJIWARA Takeshi

Journal of Japan Society for Atmospheric Environment 35 ( 6 ) 332 - 342 2000.11

Language：Japanese Publisher：Japan Society for Atmospheric Environment

In this study, dry-type reduction of mercury (II) chloride experiments were conducted using a packed bed with granular tin metal. The purpose of this study was to identify factors effecting the dry-type reduction process and to elucidate the reaction mechanism. In the reduction of mercury (II) chloride, the ratio of chlorinated surface area on tin was a vital factor. Precoating the surface of granular tin metal with 1N hydrochloric acid was effective in maintaining the reducibility. Marcury (II) chloride was reduced to mercury (0) vapor by the following two reactions on the chlorinated surface of tin metal. SnCl_2(s)+HgCl_2(g)→SnCl_4(g)+Hg(g) SnCl_2(s)+HgCl_2(g)+2H_20(g)→SnO_2(s)+Hg(g)+4HCl(g) Also, it is presumed that decreased reducibility was the result of the following oxidative reactions with tin (II) chloride. SnCl_2(s)+H_20(g)→SnO(s)+2HCl(g) SnCl_2(s)+H_20(g)+1/20_2(g)→Sn0_2(s)+2HCl(g)

Co-melting of Sediment from Lake Biwa and Sewage Sludge Incineration Ash Reviewed

TAKAOKA Masaki, TAKEDA Nobuo, OKAJIMA Shigenobu, HIRAOKA Masakatsu, FUJIWARA Takeshi

Journal of Japan Sewage Works Association 37 ( 453 ) 98 - 115 2000.7

PCDDs/DFs emissions from crematories in Japan Reviewed

Nobuo Takeda, Masaki Takaoka, Takeshi Fujiwara, Hisayuki Takeyama, Shoji Eguchi

Chemosphere 40 ( 6 ) 575 - 586 2000.3

Language：English Publishing type：Research paper (scientific journal)

Concentrations of PCDDs and PCDFs in emission gases from 10 crematories were measured. The relationship between PCDDs/DFs and several factors such as structure, equipment and operational state of the crematory is discussed. Furthermore, emission of PCDDs/DFs from all crematories in Japan is estimated. The following results are obtained: (1) total concentration of PCDDs/DFs was 2.2-290 ng/N m3, whose TEQ concentration was 0.0099-6.5 ng TEQ/N m3; (2) total concentration of PCDFs was higher than that of PCDDs; (3) T4CDFs was the highest in the homologue pattern and 2,3,7,8-T4CDF was the highest in the isomer pattern; (4) emission of PCDDs/DFs was the largest in the first 20 min of cremation; (5) concentration of PCDDs/DFs was related to the existence of a secondary combustion chamber and a dust collector, and the ratio of the numbers of main and secondary combustion chambers; (6) total emission of PCDDs/DFs from crematories in Japan was estimated to be 8.9 g TEQ/yr. (C) 2000 Elsevier Science Ltd.

DOI： 10.1016/S0045-6535(99)00232-5

Experimental Studies on the Removal Mechanism of Mercury Vapor by Synthetic Fly Ash Reviewed

TAKAOKA Masaki, TAKEDA Nobuo, FUJIWARA Takeshi

Journal of Japan Society for Atmospheric Environment 35 ( 1 ) 51 - 62 2000.1

Language：Japanese Publisher：Japan Society for Atmospheric Environment

It is the goal of this study to identify substances that have critical role in the metallic mercury removal from incineration flue gas by the coexistence with activated carbon and to clarify the metallic mercury removal mechanism by the simulated synthetic fly ash. This synthetic fly ash, which consisted of calcium chloride with 5% activated carbon, showed very high efficiency of over 99% for mercury removal at the temperature of 120℃, the moisture of 20% and air atmosphere. It was found that metallic mercury changed into mercury (II) oxychlorate on the surface of activated carbon and an oxychlorination reaction occurred in the synthetic fly ash at the temperature of air pollution control device. The metallic mercury removal mechanism by the synthetic fly ash is considered to be a chemisorption through the following route; metallic mercury→mercury (II) oxide→mercury (II) chloride→mercury (II) oxychlorate. In order to evaluate the influence of quantity of activated carbon and calcium chloride on metallic mercury removal, the experiments were performed using the synthetic fly ash which consisted of activated carbon, calcium chloride and silicon dioxide. When the calcium chloride content was more than 0.5% in the synthetic fly ash with 5% activated carbon, mercury vapor was completely removed. Whereas, the highest removal efficiencies were obtained when the activated carbon content was ranged from 5 to 7% in the synthetic fly ash with 1% calcium chloride. The mercury removal ability was affected by temperature, if the activated carbon content was very small. Because these phenomena were also observed in the experiments using calcined fly ash with 5% activated carbon, it was supposed that the complex chemical action with activated carbon and calcium chloride was most significant for metallic mercury removal by actual fly ash.

Measurement of Gaseous Components from Batch Combustion of Solid Waste. Reviewed

Norikazu Iwata, Takeshi Fujiwara, Masaki Takaoka, Nobuo Takeda

Environmental Engineering Research 37 ( Pt.2 ) 2000

Co-melting of Sediment from Lake Biwa and Sewage Sludge Incineration Ash. Reviewed

Masaki Takaoka, Masakatsu Hiraoka, Nobuo Takeda, Takeshi Fujiwara, Shigenobu Okajima

Journal of Japan Sewage Works Association 37 ( 453 ) 2000

Destruction of Polychorinated Biphenyls by Iron Compounds Reviewed

KAINUMA M.

Environmental Engineering Research 37 ( Pt.2 ) 477 - 485 2000

Application of X-ray Fluorescence Analysis to Determination of Elements in Fly Ash Reviewed

11 ( 6 ) 333 - 342 2000

The Microwave-assisted Extraction of Chlorobenzenes and PCBs from Fly Ash Reviewed

TAKAOKA Masaki, TAKADA Junichi, TAKEDA Nobuo, FUJIWARA Takeshi

Journal of the Japan Society of Waste Management Experts 10 ( 6 ) 331 - 340 1999.11

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japan Society of Material Cycles and Waste Management

A microwave-assisted extraction (MAE) method was used in the extraction of PCBs and chlorobenzenes from municipal solid waste incinerator fly ash. The highest extraction efficiency was obtained at the conditions of: 120°C of extraction temperature over 50 minutes of extraction time. At the most effective conditions, the efficiency and the precision of the MAE method were evaluated by comparing PCB and chlorobenzene levels to those of the soxhlet extraction and the supercritical fluid extraction (SFE) method, by using eight types of fly ash. MAE seems to be a viable alternative to soxhlet extraction and SFE. However, unburned carbon in the fly ash had a bad influence on the efficiency of the removal of PCBs and chlorobenzenes by MAE. The mutual relationship between chlorobenzenes and unburned carbon in fly ash was sufficiently estimated. As MAE has many advantages over soxhlet extraction, such as a shorter extraction time and a lower use of organic solvent, it is adequate for the extraction of PCBs and chlorobenzenes from fly ash.

DOI： 10.3985/jswme.10.331

Effect of Heavy Metal Recovery from Fly Ash of Ash Melting Furnace on Energy Consumption and CO_2 Emission Reviewed

FUJIWARA Takeshi, TAKEDA Nobuo, KAWABATA Hiroaki, ITO Tadashi, KATAYAMA Manabu, KUNUGIDA Eiichi

Energy and resources 20 ( 5 ) 488 - 493 1999.9

Feasibility Study on Liquefaction of Plastic Wastes -An Application for Northern Shikoku- Reviewed

FUJIWARA Takeshi, TAKEDA Nobuo

Journal of the Japan Society of Waste Management Experts 10 ( 1 ) 25 - 34 1999.1

Authorship：Lead author Language：Japanese Publisher：Japan Society of Material Cycles and Waste Management

In the law for“Promotion of Sorted Collection and Recycling of Containers and Packaging”, liquefaction is outlined as one of the resource recovery methods for ‘plastic containers with the exception of PET bottles’. In this study, an evaluation method is proposed for the liquefaction of plastic wastes over a wide area involving several local governments from the stand points of energy consumption, environmental impacts, and running costs.<BR>The northern part of Shikoku has been selected and six simulated cases with variable plastic collection ratio, locations of pretreatment and liquefaction plants were calculated. The following results were concluded: 1) approximately four times of the energy which is invested in liquefaction is yielded, 2) environmental impacts of energy consumption (CO₂, NOx and consumption of landfill space) and‘transportation costs’are considerably lower than those for‘facilities’, 3) due to scale merits the larger plant is able to save more on energy consumption and costs than the smaller plant.

DOI： 10.3985/jswme.10.25

A Fundamental Study on Solid Waste Combustion. Reviewed

Miki Taniguchi, Takeshi Fujiwara, Nobuo Takeda

Environmental Engineering Research 36 1999

Optimization of Sludge Treatment System with Pre-Coagulation Process. Reviewed

Masaki Takaoka, Kazuhiro Ohshita, Nobuo Takeda, Takeshi Fujiwara

Environmental Engineering Research 36 1999

Removal of mercury in flue gas by the reaction with sulfide compounds Reviewed

Masaki Takaoka, Nobuo Takeda, Yutaka Shimaoka, Takeshi Fujiwara

Toxicological and Environmental Chemistry 73 ( 1-2 ) 1 - 16 1999

Language：English Publishing type：Research paper (scientific journal)

The difficulty in the removal of mercury in flue gas of combustion processes is mainly due to the high volatility of elemental mercury. Various sulfide compounds were tested to check which compounds can convert mercury into stable mercury sulfide and remove mercury from flue gas. The results indicate that lead, cadmium, copper, antimony, tungsten, molybdenum, and palladium sulfides removed more than 80% of mercury from synthetic gas with mercury. On the other hand, zinc, silver, barium, calcium, and nickel sulfides were not effective for mercury removal and their removal efficiencies were less than 20%. The surface analysis using X-ray photoelectron spectroscopy suggested that mercury which reacted with sulfide compounds was presumed to form black mercury sulfide.

DOI： 10.1080/02772249909358843

Human Interface for the Operation of Waste Incineration Plant Reviewed

FUJIWARA Takeshi, TAKEDA Nobuo

Journal of Japan Society for Safety Enginennring 37 ( 2 ) 72 - 79 1998.4

Feature Extraction from Time-Series Data for Process Monitoring Reviewed

FUJIWARA Takeshi, NISHITANI Hirokazu

KAGAKU KOGAKU RONBUNSHU 22 ( 5 ) 1103 - 1110 1996.9

Language：Japanese Publisher：The Society of Chemical Engineers, Japan

A plant operator monitors time-series data of process variables to judge the state of process, diagnose abnormal states, and to identify failure origins. In this study, a new feature extraction method which extracts simultaneously both local features such as spikes and step changes, and the trend which characterizes global changes is provided from the viewpoint of process monitoring. In this method, the continuous function interpolated from the time-series data is represented by a series of inflection points first. Each time interval between two inflection points is called an episode. Then an approximation function of the time-series data is made iteratively by way of merging these episodes. This feature extraction method is also useful for compaction of a large number of process data.

DOI： 10.1252/kakoronbunshu.22.1103

Fault Detection Based On Functional Relationship Among Process Variables by Autoassociative Neural Networks Reviewed

FUJIWARA Takeshi, TSUSHI Takeshi, NISHITANI Hirokazu

KAGAKU KOGAKU RONBUNSHU 22 ( 4 ) 846 - 853 1996.7

Authorship：Lead author Language：Japanese Publisher：The Society of Chemical Engineers, Japan

Some process variables measured in a plant are strictly constrained by the material and heat balance equations, rate equations and correlations. In this study, we propose a method to judge whether the state of plant operation is normal or not, by examining whether a set of process variables maintains the functional relationship specified at normal operation. The functional relationship at normal operation is identified by an autoassociative neural network (AANN) which approximates the identity mapping for a set of measured values of process variables. An effective method to search for an adequate configuration of the AANN is also presented. Abnormal operation or fault is detected by the magnitude of discrepancy between the input vector and the output vector of the trained AANN. This fault detection method is applied to a continuous flow polymerization process and compared with the conventional 3 sigma fault detection method for a single process variable.

DOI： 10.1252/kakoronbunshu.22.846

Modelling of Overall CO₂ Emission from Industrial Activities on the Basis of Input-Output Analysis. Reviewed

Motoyuki Suzuki, Akiyoshi Sakota, Takeshi Fujiwara, Hideo Watanabe, Yasuhiro Sasaki

KAGAKU KOGAKU RONBUNSHU 19 ( 5 ) 1993

Analysis of municipal refuse incinerator system by use of auto regressive models. Reviewed

Takeshi Fujiwara, Kazushi Tsumura, Masakatsu Hiraoka

Environmental Engineering Research 25 1989

Control of dioxins from municipal solid waste incinerator Reviewed

M. Hiraoka, N. Takeda, K. Tsumura, T. Fujiwara, S. Okajima

Chemosphere 19 ( 1-6 ) 323 - 330 1989

Language：English Publishing type：Research paper (scientific journal)

The purpose of this study is to establish whether intermediate products, which are remained as unburned components and become the precursors to form the PCDD, can be reduced by improvement of the plant operation. The change of the PCDD levels was analyzed along the stream of the flue gas. Two test programs were conducted to reduce the emission levels of PCDD at municipal solid waste (MSW) incinerators. They were as follows; 1. (1) High temperature incineration to reduce unburned components. 2. (2) Investigation of the relationship between CO contents and PCDD levels at an incinerator which was operated by reductive two-step combustion mode to reduce NOx emission level. © 1989.

DOI： 10.1016/0045-6535(89)90331-7

Simultaneous control of steam flow rate and NOx in the municipal refuse incinerator by use of coordinated ACC and AR control.

Takeshi Fujiwara, Kazushi Tsumura, Masakatsu Hiraoka, Katsumi Takaichi, Sin-ichi Tsujimoto

Environmental & sanitary engineering research 1 1987

Automatic control of municipal waste incinerators. Reviewed

Masakatsu Hiraoka, Kazushi Tsumura, Takeshi Fujiwara

Environmental conservation engineering 16 ( 10 ) 1987

Multipurpose combustion control system of refuse incinerator by use of autoregressive model. Reviewed

Masakatsu Hiraoka, Kazushi Tsumura, Takeshi Fujiwara, Katsumi Takaichi, Sin-ichi Tsujimoto

Journal of Solid Wastes 16 ( 9 ) 1986

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