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

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J-GLOBAL

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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

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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

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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

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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

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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

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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

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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

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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

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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

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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

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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

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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

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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

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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

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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

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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

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

J-GLOBAL

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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

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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

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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

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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

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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

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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

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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

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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

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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

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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

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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

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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

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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

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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

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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

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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

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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

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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

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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

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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

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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

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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

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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

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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

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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

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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

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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

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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

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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

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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

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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

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DOI： 10.2208/journalofjsce.5.1_123

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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

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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

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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

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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

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DOI： 10.4172/2252-5211.1000140

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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

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Publisher：Japan Society of Material Cycles and Waste Management  

Guam island of&nbsp;US accepts about 1.1 million tourists every year comparing topopulation&nbsp;&nbsp;160,000, and over 80% of tourists is Japanese.&nbsp; 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.&nbsp; 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. &nbsp;Due to less resources and small number of industries except tourism, Guam island has to import many goods from oversea.&nbsp; 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&rsquo;s expense.&nbsp; 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

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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.&nbsp; Moreover, evaluation method to find better locations and suitable for temporal storage yard by considering&nbsp;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

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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

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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

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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

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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

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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 &apos;food&apos;, &apos;household appliances&apos; and &apos;amusement & education&apos; 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

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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.

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

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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

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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

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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

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Language：Japanese   Publishing type：Research paper (scientific journal)   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&deg;C) of municipal solid waste incinerator was investigated. When fly ash was heated with mixture of 2% Na₂S at the condition of 300&deg;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

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

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

Language：Japanese   Publishing type：Research paper (scientific journal)   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&sdot;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

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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

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

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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

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Language：Japanese   Publishing type：Research paper (scientific journal)   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.

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DOI： 10.11532/proes1992.37.477

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DOI： 10.3985/jswme.11.333

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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&deg;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

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In the law for&ldquo;Promotion of Sorted Collection and Recycling of Containers and Packaging&rdquo;, liquefaction is outlined as one of the resource recovery methods for &lsquo;plastic containers with the exception of PET bottles&rsquo;. 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&lsquo;transportation costs&rsquo;are considerably lower than those for&lsquo;facilities&rsquo;, 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

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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

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japan Soceiety for Safety Engineering  

DOI： 10.18943/safety.37.2_72

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

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Authorship：Lead author   Language：Japanese   Publishing type：Research paper (scientific journal)   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

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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

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Total pages：257   Language：Japanese

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Total pages：xvii, 1339p   Language：Japanese

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

Due to the heavy rain that hit West Japan in July 2018, a large-scale flood occurred in Maki-machi, Kurashiki city due to the river collapse on the 7th, and the heavy rain that hit West Japan in July resulted in 7 in Mabi-cho, Kurashiki-shi. Large-scale floods occurred daily due to river collapse, resulting in approximately 440,000 tons of flood damage. When the house cleaning starts, they are discharged all at once in the area, which causes a shortage of storage space and waiting for garbage collection. In Mabi-cho, there is an illegal discharge site where citizens can bring in garbage by car under the elevated road construction site along National Route 486 and under the Ihara Railway Ihara Line, and the Self-Defense Forces will remove it. In order to control the discharge of clean-up trash immediately after the occurrence of a disaster and to make a plan to collect it quickly, it is effective to first analyze the clean-up trash discharge behavior actually taken by the victims. Therefore, in this study, we conducted a questionnaire survey on the victims of Mabi-machi, Kurashiki city, and analyzed the recognition of discharge rules, the possibility of separation, the place of waste discharge, and the reason why they were dumped at illegal discharge sites.

DOI： 10.14912/jsmcwm.31.0_113

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

Due to the heavy rain that hit western Japan in July 2018, a large-scale flood occurred in Manabi-cho, Kurashiki city on the 7th, which caused about 440,000 tons of flooded waste. When the cleaning of houses starts after the disaster, they are discharged all at once in the area, which causes a shortage of storage space and waiting for garbage collection. In previous research 1), it was found that if the collection of waste is delayed, the storage space becomes full, which causes illegal discharge. In the event of a disaster, it is necessary to smoothly collect and remove disaster waste from the disaster area, and for that purpose, it is important to first understand the characteristics of the waste discharge time of clean-up waste. In this study, we conducted a questionnaire survey on the victims of Mabi-machi, Kurashiki City, clarified the emission characteristics and emission timing of each type of cleanup waste, and created an emission model. Then, for the waste discharge from the target area, a collection strategy was established and a collection simulation was conducted.

DOI： 10.14912/jsmcwm.31.0_117

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Authorship：Lead author   Language：Japanese   Publishing type：Article, review, commentary, editorial, etc. (scientific journal)   Publisher：環境技術学会  

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Publisher：Japan Society of Material Cycles and Waste Management  

DOI： 10.14912/jsmcwm.26.0_371

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Publisher：Japan Society of Material Cycles and Waste Management  

As a first step of research on evaluating effectiveness<br>of distributed biomass recycling system of business facility or regional unit,<br>in this study, we estimated the quantity of biomass waste which is generated<br>from green area, agricultural field, and cafeterias on a big campus of Okayama<br>University.  Each quantity of pruned fruits<br>branch, cut grass, rice straw, and animal waste was estimated by using the<br>calculation method of NEDO, crop waste was estimated by using a farm report published<br>by Faculty of Agriculture, and pruned and fallen leaves were estimated by using<br>the allometry method which estimates amount of leaves based on trunk diameter<br>and tree height.  The amount of the<br>kitchen waste generated from university cafeteria was figured out by hearing to<br>university Co-op.  As a result, it was<br>found that the amount of biomass waste generated on Okayama University campus is<br>1,454 ton/year.  If the biomass is burned<br>or used for bio gas generation, the electricity generation will be 6,765<br>GJ/year.

DOI： 10.14912/jsmcwm.26.0_19

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Language：Japanese   Publisher：京都大学環境衛生工学研究会  

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Authorship：Lead author   Language：Japanese   Publishing type：Article, review, commentary, editorial, etc. (trade magazine, newspaper, online media)  

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DOI： 10.14912/jsmcwm.25.0_59

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Language：Japanese   Publisher：京都大学環境衛生工学研究会  

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Iskandar Malaysia (IM) is a new economic region in Malaysia’s<br>most southern state, Johor. The region is targeted for massive development by<br>2025 with a targeted rapid increase in the population to 3<br><br>million, or double the 2005 level, within the 20-year development period. IM<br>was chosen as the study area of “Low-carbon society for Iskandar Malaysia 2025”<br>which has an action “Sustainable Waste Management” in 12 countermeasure actions<br>towards climate resilient urban development for Iskandar Malaysia. In this<br>paper, we evaluated alternative solid waste management towards the building of<br>both a sound material society and a low-carbon society. This study covers five<br>sectors namely management of municipal solid waste, agricultural waste,<br>industrial waste, sewage sludge, and construction and demolition waste. Our target<br>is half reduction of landfill waste and half of GHG emitted from waste handling<br>and treatment. Our result shows that both the target are achievable in 2025<br>with the reduction of 65%, 79%, 81%, 10%, 69% of waste and reduction as GHG<br>emission as well, respectively. Targets are achievable under the condition of<br>high participation and segregation efficiency in 2025.

DOI： 10.14912/jsmcwm.24.0_75

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Publisher：Japan Society of Material Cycles and Waste Management  

<br><br>In the recent year, there is the trend of municipal<br>solid waste (MSW) decreasing in many local governments.  Some of the reasons of<br>this trend are due to changes in socioeconomic<br>factor such as decreasing in population number and economic stagnation and positive impact factor of<br>3R – reduce, reuse, recycle; promotion. However, it is<br>difficult to explain the reason of MSW decreasing through decoupling the effects<br>from each factor.  It is required for<br>local government to make planning of treatment facility from long time prospect<br>of waste discards.  In this study, we conduct waste characterization<br>test to analyze the relationship between consumption and waste discards for<br>targeted Okayama City, and develop a model for projecting future waste discards<br>based on a scenario of economic stagnation or recycling promotion.

DOI： 10.14912/jsmcwm.24.0_13

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Language：Japanese   Publisher：京都大学環境衛生工学研究会  

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Language：Japanese   Publisher：Japan Society of Civil Engineers  

Pacific island country without having manufacturing industry emphasizies on tourism industry which utilizes the natural resources. Island country imports lots of foods and commodity goods from oversea countries to supply for tourists during their stays, moreover, changes in resident's lifestyle from 'thrift type' to 'waste type' increases the amount import even more. The goods consumed by resident or tourist, has been disposed and stored in the island, and at present, the stored waste causes environmental pollution and landscape deterioration. Since small island country has difficulty in constructing final landfill, it is important to prevent waste generation due to construct a sound material-cycle society with a view of collaboration with foreign countries. For this purpose, by considering development in island economy and change in lifestyle of island people, it is necessary to identify the quality and quantity of solid waste which is generated at the present and future.<br> In this research, Guam, a territory of U.S., is targeted. First of all, input-output table is developed to grasp the current economic situation of the island, and secondly, scenarios which are composed of changes in population of residents, future number of tourists, and expenditure to tourism industry are created. Then, the amount of discharged future household waste is estimated by considering economic ripple effect under the scenario.

DOI： 10.2208/jscejer.68.i_41

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Language：Japanese   Publisher：全国都市清掃会議  

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The new Malaysia modern city, Putrajaya is being developed rapidly according to the transfer of central government functions from capital city Kuala Lumpur. Malaysia government is planning to make Putrajaya the showcase city for 'Pioneer Township in Green Technology' through 'Putrajaya Green City 2025' preliminary study. As part of '3R Putrajaya' that tackles solid waste management, with the target to reduce half of both landfilled waste amount and GHG emission from waste management counter measures compare to the BaU (Business as Usual) case, we developed planning on low carbon collection and treatment of municipal solid waste using GIS software. Base on seven scenario options of waste treatment in 2025, waste transportation route, distance, GHG emission, and cost were calculated. Each scenario options were compared and the best alternative for low carbon waste transportation was proposed.

DOI： 10.14912/jsmcwm.22.0.33.0

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DOI： 10.14912/jsmcwm.21.0.39.0

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

Japan is one of the countries experiencing the most serious flood disasters in the world. In recent years, flood disasters resulted from intensive heavy rainfall events occur frequently, leading to a lot of victims. When such flood disaster occurs, a large amount of flood disaster waste, e.g. household goods, would be discharge from flood-damaged houses. Hence, in this sense, a lot of problems would happen, such as disordered waste collection and transportation activities and the insufficient emergent capability of waste treatment facilities, etc. However, to conduct quick and proper waste collection and transportation programs, firstly the estimation of flood disaster waste discharge is required. Therefore, take one past flood event in Kurashiki City as a case study, this research conducted a questionnaire survey, estimated the amount of its flood disaster waste discharge based on the survey results in support of waste collection, transportation and treatment actions, and consequently examined the reproducibility of the flood disaster waste discharge process.

DOI： 10.14912/jsmcwm.21.0.40.0

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In order to modify the waste charging in Taiwan, it is imperative to examine the feasibility and policy effects of the operating pay-as-you-throw (PAST) systems. Therefore, this study aims at analyzing the policy effect of the PAST system in Taipei City where sufficient waste data regarding the PAST is available. Meanwhile, other influencing factors of HSW generation in Taipei City would be exploited so that efficient policy measures for waste reduction could be proposed.

DOI： 10.14912/jsmcwm.21.0.301.0

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Nowadays about 5% of industrial wastes (22 million ton) are not recycled. One reason of this problem is that are unavailable for the factories to look up an optimal process flow. Thus this study aims to develop a technology database of treatment process, cost, energy consumed, and environmental loading of the process for industrial waste so that the most efficient and environmental-friendly process flow can be easily searched. Microsoft Excel is used to establish the platform of the database and to develop the interface of data input. Further, estimation formulas can be performed in this database system and parameters for advanced evaluation can be easily queried. By this developed system, after inputting the initial values of a processing, the whole flow the list of process flow candidates will be shown and the comparisons between the theoretical output and actual measurements can be performed. Further, advanced financial and environmental evaluation of the interested process can be achieved.

DOI： 10.14912/jsmcwm.21.0.26.0

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Other Link： http://hdl.handle.net/2433/153311

Language：English   Publisher：京都大学環境衛生工学研究会  

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Industrialization and urbanization result in significant changes in lifestyle. These lifestyle changes seem to lead to unsustainable consumption patterns and increase the generation of various kinds of environmental loads, especially the amount of municipal solid waste (MSW). Taiwan is a small island with scarce natural resources. The economic development in Taiwan has resulted in the generation of large amounts of MSW. As a result, the Taiwan Environmental Pollution Administration (TEPA) has produced regulations for waste minimization and has imposed several important policy measures that have successfully reduced the MSW discard rate in recent years and have established a public recycling network as a part of the MSW collection. Nowadays, the objective of the MSW policies in Taiwan is to develop a "zero-waste society." This article aims to review the MSW management progress in Taiwan and to project future MSW discards up to 2011 based on the national plan and assumed scenarios for socioeconomic variables. According to the analysis results, a more sustainable consumption pattern can be proposed and the corresponding MSW management system can be planned so as to develop a low-waste-discard society. © 2009 Springer Japan.

DOI： 10.1007/s10163-008-0233-1

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Language：English   Publisher：SPRINGER  

Industrialization and urbanization result in significant changes in lifestyle. These lifestyle changes seem to lead to unsustainable consumption patterns and increase the generation of various kinds of environmental loads, especially the amount of municipal solid waste (MSW). Taiwan is a small island with scarce natural resources. The economic development in Taiwan has resulted in the generation of large amounts of MSW. As a result, the Taiwan Environmental Pollution Administration (TEPA) has produced regulations for waste minimization and has imposed several important policy measures that have successfully reduced the MSW discard rate in recent years and have established a public recycling network as a part of the MSW collection. Nowadays, the objective of the MSW policies in Taiwan is to develop a "zero-waste society." This article aims to review the MSW management progress in Taiwan and to project future MSW discards up to 2011 based on the national plan and assumed scenarios for socioeconomic variables. According to the analysis results, a more sustainable consumption pattern can be proposed and the corresponding MSW management system can be planned so as to develop a low-waste-discard society.

DOI： 10.1007/s10163-008-0233-1

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DOI： 10.1177/2009.9.11

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DOI： 10.1177/2009.9.11

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Language：Japanese   Publisher：Society of Environmental Conservation Engineering  

The policy of waste to energy (WTE) has been promoted as an important policy for alternative energy and one of the principle infrastructure plans of the Japanese government. However, problems with dioxin have necessitated various changes of WTE technology, and WTE facilities now must have flue gas treatment equipment with long-chain process , ash melting furnace , and gasification and melting furnace. Although WTE facilities with the disposal capacity of 300t/d or greater have been considered to be more effective and desirable, the number of these facilities has not increased, and WTE facilities with capacity of less than 300t/d have been increasing in compliance with the dioxin guidelines for continuous combustion and regional waste disposal. This study investigates and analyzes the generation, purchase and consumption of electricity / fossil fuels using the operation and maintenance data of all of WTE facilities operated in 2007 in Japan. Our findings show that the smaller the capacity of WTE facility , the greater the consumption of electricity and energy per ton. In the future it may be recommended that WTE facilities of 300t/d or greater be increased and the ash from several WTE facilities be treated jointly.

DOI： 10.5956/jriet.38.624

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Other Link： https://jlc.jst.go.jp/DN/JALC/00337950481?from=CiNii

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

A one-month survey focused on 100 households was conducted in Can Tho City. The household solid waste was collected from each household and classified into 83 categories. The results showed that the average household solid waste generation in Can Tho City was 0.29 kg per capita per day with high compostable portion and recyclable as 82% and 10%, respectively. The household solid waste generation rate (kg/cap/day) was positively correlated with the population density, while it was negatively correlated with the household size. Moreover, the discharge amount per capita per day of household solid waste by each fraction is positively correlated with the urbanization level.

DOI： 10.14912/jsmcwm.20.0.281.0

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Language：Japanese   Publisher：Society of Environmental Conservation Engineering  

The policy of waste to energy (WTE) has been promoted as an important policy for alternative energy and one of the principle infrastructure plans of the Japanese government. However, problems with dioxin have necessitated various changes of WTE technology, and WTE facilities now must have flue gas treatment equipment with long-chain process , ash melting furnace , and gasification and melting furnace. Although WTE facilities with the disposal capacity of 300t/d or greater have been considered to be more effective and desirable, the number of these facilities has not increased, and WTE facilities with capacity of less than 300t/d have been increasing in compliance with the dioxin guidelines for continuous combustion and regional waste disposal. This study investigates and analyzes the generation, purchase and consumption of electricity / fossil fuels using the operation and maintenance data of all of WTE facilities operated in 2007 in Japan. Our findings show that the smaller the capacity of WTE facility , the greater the consumption of electricity and energy per ton. In the future it may be recommended that WTE facilities of 300t/d or greater be increased and the ash from several WTE facilities be treated jointly.

DOI： 10.5956/jriet.38.624

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Other Link： https://jlc.jst.go.jp/DN/JALC/00337950481?from=CiNii

The increasing municipal solid waste (MSW) generation and the options of appropriate MSW treatment technologies are particularly highlighted on its worldwide impact on the global warming in recent times. It is imperative to assess the potential amount of the greenhouse gas (GHG) emission in the design of MSW treatment and disposal system. This study aims at developing an emission inventory of GHG emission from the MSW treatment and disposal system, by firstly using the IPCC's updated methodology and domestic studies for required parameters in Taiwan. The GHG emission rates from respective MSW treatment and disposal divisions are estimated. The methane emission behavior between the first-order decay model and the triangular method is also firstly compared. Accordingly, the MSW treatment and disposal system in Taiwan generated 7,842.6 Gg CO< equivalence in 2002, occupying 2.86 % of Taiwanese net GHG emission in that year. The analysis results also indicate that plastic waste, paper waste, and food waste occupies the largest share of GHG emission from MSW treatment and disposal processes. Thus recycling and reducing activities on them should be enhanced for preventing global warming. The results will help the decision-makers associated with GHG reduction and MSW management to make efficient policy strategies.

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Language：English  

DOI： 10.14912/jswmepac.19.0.300.0

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Language：English  

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Language：English   Publisher：京都大学環境衛生工学研究会  

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Language：English   Publisher：京都大学環境衛生工学研究会  

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Language：Japanese   Publisher：Japan Society of Civil Engineers  

The waste collection and transfer system is requisite for establishing widen regional waste management in prefectural level. In this study, we propose a new method to estimate transport distance between collection area and the waste transfer facility by using GIS and to solve optimal location problem of the facility. Takahasi block, that is a group of local municipalities located in the northern west of Okayama prefecture, is selected as a target area of this case study. Firstly, waste emission map is created based on not only the information of collection area and municipal solid waste by the treatment facility but also the information of population and households by the town. Secondly, we proposed an algorithm of generating a group of the adjusted waste collection area so that waste collection volume in the area can approach to the loading capacity limitation. In order to evaluate the distance between the collection area and the transfer facility, 'the weighted average transport distance with the waste amount' per one trip of collection car is proposed. Finally, the one-dimensional search method along the trunk line is applied for solving the location optimization problem of the waste transfer facility. Additionally, this result is compared to the transport distance of the current treatment condition based on local incineration, moreover, the proposed models is compared to Grid City Model.

DOI： 10.2208/proer.36.299

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Language：Japanese   Publisher：Japan Society of Civil Engineers  

The waste collection and transfer system is requisite for establishing widen regional waste management in prefectural level. In this study, we propose a new method to estimate transport distance between collection area and the waste transfer facility by using GIS and to solve optimal location problem of the facility. Takahasi block, that is a group of local municipalities located in the northern west of Okayama prefecture, is selected as a target area of this case study. Firstly, waste emission map is created based on not only the information of collection area and municipal solid waste by the treatment facility but also the information of population and households by the town. Secondly, we proposed an algorithm of generating a group of the adjusted waste collection area so that waste collection volume in the area can approach to the loading capacity limitation. In order to evaluate the distance between the collection area and the transfer facility, 'the weighted average transport distance with the waste amount' per one trip of collection car is proposed. Finally, the one-dimensional search method along the trunk line is applied for solving the location optimization problem of the waste transfer facility. Additionally, this result is compared to the transport distance of the current treatment condition based on local incineration, moreover, the proposed models is compared to Grid City Model.

DOI： 10.2208/proer.36.299

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

Capacity planning of municipal solid waste (MSW) processing system, including the intermediate treatment and disposal facilities, is crucial in MSW management system, especially for the developing countries. Inappropriate intermediate treatment and disposal of MSW would lead to detrimental damage to the public health and natural environment. Moreover, the MSW emission rate in terms of the socioeconomic changes should be further considered in the capacity planning on MSW system. By using the estimation model system of MSW emission, established in the author's previous work, this study aims to conduct a short-term capacity forecasting of MSW processing system, up to 2011. Possible ranges of the available remaining capacity of MSW processing system are projected based on the assumed scenarios. Such capacity forecasting will provide necessary information for the policy decision-makers.

DOI： 10.14912/jswmepac.19.0.303.0

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Language：Japanese   Publisher：日本建築士事務所協会連合会  

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Language：Japanese   Publisher：Japan Society of Civil Engineers  

An estimation model of household's waste which is available for local government to make plans of waste management was developed. The mass of household waste is estimated using household's final consumption expenditure, household's attributes, price of goods, and waste conversion rate. The model is a comprehensive multilayered model representing consumption structure. LES (Linier Expenditure System) model is applied to disaggregate the fmal consumption expenditure to expenditures of major consumption categories, and the multinomial logit model is applied to disaggregate the major consumption expenditure to expenditures of intermediate consumption categories, constant rate is used to disaggregate the intermediate consumption expenditure to the expenditures of small categories, and the expenditure disaggregated finally is converted to the mass of corresponding waste category. This model was applied to estimate the waste generation of Kyoto city using the census of household consumption, as a result, effectiveness of the model was proved through evaluating error in the estimation of kitchen garbage.

DOI： 10.2208/proer.35.471

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Publisher：Japan Society of Civil Engineers  

Social, economic and environment is a composite dynamic system."Mass production, and mass consumption, and mass discarded waste" has been a popular phenomenon in modern society, especially in developing countries. Literatures have indicated consumption is a driving factor of environmental loads but only few give quantitative results. In this study, individual's waste generation by waste component category is simulated via simultaneous equation system regarding for the consumption structure by a case study of Taiwan. Firstly, precise estimation models are developed, and analysis results not only identify the household waste generation loads of consumer's behavior explicitly, but also provide an analytic framework to evaluate performance of relevant policies.

DOI： 10.2208/proge.15.117

CiNii Article

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Publisher：Japan Society of Civil Engineers  

Social, economic and environment is a composite dynamic system."Mass production, and mass consumption, and mass discarded waste" has been a popular phenomenon in modern society, especially in developing countries. Literatures have indicated consumption is a driving factor of environmental loads but only few give quantitative results. In this study, individual's waste generation by waste component category is simulated via simultaneous equation system regarding for the consumption structure by a case study of Taiwan. Firstly, precise estimation models are developed, and analysis results not only identify the household waste generation loads of consumer's behavior explicitly, but also provide an analytic framework to evaluate performance of relevant policies.

DOI： 10.2208/proge.15.117

CiNii Article

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J-GLOBAL

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Language：Japanese   Publisher：Japan Society of Civil Engineers  

An estimation model of household's waste which is available for local government to make plans of waste management was developed. The mass of household waste is estimated using household's final consumption expenditure, household's attributes, price of goods, and waste conversion rate. The model is a comprehensive multilayered model representing consumption structure. LES (Linier Expenditure System) model is applied to disaggregate the fmal consumption expenditure to expenditures of major consumption categories, and the multinomial logit model is applied to disaggregate the major consumption expenditure to expenditures of intermediate consumption categories, constant rate is used to disaggregate the intermediate consumption expenditure to the expenditures of small categories, and the expenditure disaggregated finally is converted to the mass of corresponding waste category. This model was applied to estimate the waste generation of Kyoto city using the census of household consumption, as a result, effectiveness of the model was proved through evaluating error in the estimation of kitchen garbage.

DOI： 10.2208/proer.35.471

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Publisher：Japan Society of Civil Engineers  

In this study, we applied energy end-use model to estimate air pollution emissions by considering the use ofenergy devices which are decided from energy demand. In the second, the total emission with time variation that wasemitted from sectors was disaggregated into the regions of target area, and finally, by using the meso-scale metheorologymodel (MM5) and the chemical transfer model (CMAQ), the chemical transformation and transportation at the presentand in the future were computed in the three different spatial scales. Accuracy in long range transportation of thedeveloped model was validated through comparison between the estimated value and the observation by the East Asian Monitoring Networks.<BR>From the result of finest domain, the background concentration of NO₂ was 2-4 ppb in the year average concen trationand about 19 ppb in the maximum of day average concentration, and the possibility was clarified that NO₂ concentrationin Beijing sometimes is pushed up over Chinese standard of air quality by the NO₂ transported from the outside. Moreover, SO₂ and NOx emissions in 2020 were estimated by the end-use model, and the concentration of the each gasin Beijing was calculated and analyzed. As a result, the concentration in 2020 was over three times higher than that in 2001, and it was specially pointed that SO₂ in winter and NO₂ in summer are remarkably high.

DOI： 10.2208/proge.15.83

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Publisher：Japan Society of Civil Engineers  

In order to clarify the actual conditions of emissions of environmental loads in Asia, we estimated emissions from energy consumption and agriculture in 2001 and developed emissionsinventories with ArcGIS.<BR>To estimate the emissions of NOx, SO₂ and CO₂ from energy consumption, we calculated theservice demands of each sector by using economic model and constructed the energy enduse model. We also estimated the emissions of NOx, SO₂, CO₂, CH₄, NH₃ and N₂O from agriculture in eachemission resource. Then the emissions are spatially distributed by using the landuse data and largepoint source (LPS) data such as electric power plants including its longitude and latitude data.<BR>As a result, we estimated total emissions of NOx, SO₂ and CO₂ are 31.1 (Tg), 29.5 (Tg), 6026.2 (Tg), and the large amount of the emissions is from electric power plants. The results of spatialdistribution of these gases show that these gases have concentrated exhaust source on a specific place. We also estimated emissions of CH₄, NH₃ and N₂O from agriculture are 69.4 (Tg), 15.0 (Tg), 3245.8 (Gg), and the largeamount of these gases is emitted from the north part of India.

DOI： 10.2208/proge.15.43

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Language：Japanese   Publisher：京都大学環境衛生工学研究会  

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Language：Japanese   Publisher：京都大学環境衛生工学研究会  

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Language：Japanese   Publisher：廃棄物学会  

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Language：Japanese   Publisher：Japan Society of Civil Engineers  

Recently, Information Technology (IT) has spread quickly in Japan. In this study, we developed a model to estimate the influence of IT on industrial economy and to estimate the related environmental load. This model consists of two modules, input-output analysis module and energy conversion module. The former module estimates multiplied effects of adoption of IT on industry economy, and the latter module calculates CO₂ emission by using the relationship between the emission and industrial production. An IT spreading scenario including evolution of broadband network, electronic commerce (BtoB and BtoC), and telework was considered. As a result of our estimation, demand for power sector increased, and CO₂ emitted from oil products decreased due to reduction of transportation. Total CO₂ emission increased because of large amounts of demands for the power sector.

DOI： 10.2208/proge.13.145

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Language：Japanese   Publisher：京都大学環境衛生工学研究会  

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Language：Japanese   Publisher：エネルギー・資源学会  

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Language：Japanese   Publisher：廃棄物学会  

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Language：Japanese   Publisher：京都大学環境衛生工学研究会  

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Language：Japanese   Publisher：京都大学環境衛生工学研究会  

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Language：Japanese   Publisher：京都大学環境衛生工学研究会  

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Language：Japanese   Publisher：EICA環境システム計測制御学会  

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Publisher：Japan Society of Civil Engineers  

Sixty percents of people in the world live in Asian area, and their economic activities earn twenty four percents of the total GDP all over the world. As the population increases and the economic activities, emissions of sulfur oxides and nitrogen oxides from combustion are increasing and the emissions cause not only local pollution but also global environmental pollution.<BR>It is important to calculate the concentration of sulfur oxides that is emitted from the stack of large point sources. In this paper, a software package was developed to calculate the diffusion of sulfur oxides which is emitted from Asian large point sources by using the Japanese air pollution model, and this package was applied to diffusion problems by large point sources China, Korea and India's. The result is displayed as figures with GIS and the diffusion in each country was discussed.

DOI： 10.2208/proge.10.245

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