Faculty Profiles - FUJIWARA Takeshi

Papers - FUJIWARA Takeshi

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

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

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

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

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

DOI： 10.1088/1755-1315/307/1/012019

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

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

Sustainability 11 ( 5 ) 1228 2019.3

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

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

DOI： 10.3390/su11051228

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

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

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

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

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

DOI： 10.1007/s10163-018-0807-5

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

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

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

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

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

DOI： 10.1504/IJEWM.2019.099015

Analyzing solid waste management practices for the hotel industry Reviewed

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

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

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

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

DOI： 10.22034/gjesm.2018.04.01.003

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

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

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

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

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

DOI： 10.22034/gjesm.2018.04.002

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

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

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

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

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

DOI： 10.1088/1755-1315/159/1/012041

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

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

Journal of Cleaner Production 176 726 - 735 2018.3

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

DOI： 10.1016/j.jclepro.2017.12.110

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

Chooi Mei Mah, Takeshi Fujiwara, Chin Siong Ho

Journal of Cleaner Production 172 3415 - 3427 2018.1

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

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

DOI： 10.1016/j.jclepro.2017.11.200

Suitability assessment for handling methods of municipal solid waste Reviewed

B. Seng, T. Fujiwara, B. Seng

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

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

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

DOI： 10.22034/gjesm.2018.04.02.001

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

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

Chemical Engineering Transactions 63 355 - 360 2018

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

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

DOI： 10.3303/CET1863060

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

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

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

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

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

DOI： 10.22034/GJESM.2018.03.001

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

Bandith Seng, Takeshi Fujiwara, Vin Spoann

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

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

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

DOI： 10.1177/0734242X/18790800

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

Vin Spoann, Takeshi Fujiwara, Bandith Seng, Chanthy Lay

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

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

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

DOI： 10.1177/0734242X18785722

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

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

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

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

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

DOI： 10.1088/1755-1315/159/012046

Environmental impacts of construction and demolition waste management alternatives Reviewed

Chooi Mei Mah, Takeshi Fujiwara, Chin Siong Ho

Chemical Engineering Transactions 63 343 - 348 2018

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

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

DOI： 10.3303/CET1863058

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

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

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

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

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

DOI： 10.1177/0734242X17738338

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

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

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

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

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

DOI： 10.1016/j.jenvman.2016.05.033

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

Jinmei Yang, Takeshi Fujiwara, Qijin Geng

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

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

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

DOI： 10.1007/s10163-016-0540-x

Predicting waste generation using Bayesian model averaging Reviewed

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

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

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

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

DOI： 10.22034/gjesm.2017.03.04.005

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