Evaluating the urban metabolism sustainability of municipal solid waste management system: An extended exergy accounting and indexing perspective
ارزیابی متابولیسم شهری پایداری سیستم مدیریت ضایعات جامد شهری: حسابداری اگزرژی گسترده و دیدگاه نمایه سازی-2021
In this study, Extended Exergy Accounting was adopted to develop an accounting model to evaluate the performance of a Municipal Solid Waste Management System. Furthermore, urban metabolism sustainability index for waste was also proposed to represent the unified society-economy-environment impacts of the MSWMS under the framework of a comprehensive sustainability evaluation. A detailed analysis of wood and horticultural waste treatment scenarios in Singapore was done as a case study. It was found that the gasification scenario theoretically performs significantly better than the incineration scenario, in terms of energy carrier consumption, emissions, thermodynamic efficiency and sustainability. Analysis results show that, if extrapolated to Singapore’s total wood and horticultural waste, gasification technology has potential to reduce energy consumption and increase electricity output. An uncertainty analysis was carried out and it was found that the main extended exergetic parameters of the two scenarios considered were in the range of 3–8%, thus confirming the reliability of the accounting results. A sensitivity analysis of the urban metabolism sustainability index for waste was conducted for the gasification scenario to identify key influencing factors and seek potential improvements; this was done by considering changes in four variables: transportation distance, electrical efficiency, working hour increment and gross capital cost per ton waste treated. It was found that, to ensure the feasibility and sustainability of gasification scenario, the following are required: keeping the electricity production efficiency greater than 21.33%; the transportation distance between the gasification power plant and source of wood and horticultural waste should be kept within 17.08 km; employment of per kton annual treatment capacity should be less than 0.14 workers; wood and horticultural waste source should control the waste collection frequency of no more than 3 times per day and the number of workers participating in the collection each time is less than 4 persons, totaling to 12 workers per day.
keywords: تجزیه و تحلیل Exergy را گسترش دهید | زباله جامد شهری | ارزیابی پایداری | متابولیسم شهری | اگزرژی کار | Exergy اصلاح محیط زیست | Extend exergy analysis | Municipal solid waste | Sustainability assessment | Urban metabolism | Labor exergy | Environmental remediation exergy
Modeling and identification of suitable motivational mechanism in the collection system of municipal solid waste supply chain
مدل سازی و شناسایی سازوکار انگیزشی مناسب در سیستم جمع آوری زنجیره تأمین پسماند جامد شهری-2021
Many studies have identified that incentive, subsidy, and reward-penalty mechanisms improve the col- lection rate of recyclables and end of life products. But there is a lack of studies mathematical models and analysis of these mechanisms in the context of municipal solid waste supply chain. Therefore, in this study, models have been formulated for municipal solid waste supply chain (profit) considering government and collectors’ profit under incentive, subsidy, and reward-penalty mechanisms. The study has analysed the models against the non-separation and separation scenario of waste. A numerical analysis is performed and observed that: (i) separation of waste at source along with incentive, subsidy, and reward-penalty mechanisms scenario improve the collection rate by 17%, 23%, 30%, and 45% compared to non-separated MSW. (ii) Incentive, subsidy, and reward-penalty mechanisms increases the total sup- ply chain profit by around 9%, —36% and 18%. (iii) reward-penalty mechanism performs better than incentive and subsidy mechanism by providing the high supply chain profit (18% and 85%) and collection rate (22% and 15%) comparatively. Further, sensitivity analysis carried out to understand the behaviour of the models against the key parameters. The study also develops interesting propositions and proved for a better understanding of the models. From results, some key managerial insights have been drawn and a few future scopes of the study are presented.© 2021 Elsevier Ltd. All rights reserved.
Keywords: Solid waste supply chain | Circular economy | Incentive | Subsidy | Reward-penalty
Optimal process design for integrated municipal waste management with energy recovery in Argentina
طراحی فرآیند بهینه برای مدیریت یکپارچه زباله شهری با بازیابی انرژی در آرژانتین-2020
This work presents a comprehensive mathematical model for the optimal selection of municipal waste treatment alternatives, accounting for co-digestion of sludge and municipal solid waste. The superstructure of alternatives includes anaerobic digestion under mesophilic or thermophilic conditions, composting, recycling, and final disposal in a landfill. Anaerobic digesters can be fed with different mixing ratios of sewage sludge (SS) and the organic fraction of municipal solid waste (OF). A mixedinteger mathematical programming formulation is proposed to find the optimal process design. It comprises nonlinear equations to estimate digestion yields according to substrate mixing ratios. Results for cities of different sizes show that the joint treatment can increase profitability, especially in small populations. In all cases, co-digestion of the full stream of SS and OF leads to an integrated waste-toenergy process that maximizes the economic value and reduces environmental impacts of waste by producing electricity, heat and fertilizer.
Keywords: Co-digestion | Waste-to-Energy | Optimization | Superstructure | Process design
Electricity generation using biogas from organic fraction of municipal solid waste generated in provinces of China: Techno-economic and environmental impact analysis
تولید برق با استفاده از بیوگاز از کسری آلی پسماندهای جامد شهری تولید شده در استانهای چین: تحلیل تأثیر تکنو اقتصادی و زیست محیطی-2020
This study assessed the electricity generation potential of biogas from organic fraction of municipal solid waste collected for disposal from 2004 to 2018 in 31 provinces of China using landfill gas to energy (LFGTE) and anaerobic digestion (AD) technologies. Economic feasibility assessment of the technologies was carried out using Net Present Value, and Levelized Cost of Energy methods. In addition, environmental impact of waste management options based on global warming potential was assessed under three scenarios. Key findings showed that electricity generation potential of anaerobic digestion technology was higher in all the provinces. Economically, the results showed that both projects are feasible in all the 31 provinces. However, anaerobic digestion project proved to be highly feasible, with more positive net present value, and lower levelized cost of energy. Sensitivity analysis showed that both projects are infeasible with a discount rate beyond 20%. The results also showed that landfill gas without energy recovery has high global warming potential. It was realized that on the average landfill gas to energy technology could reduce global warming potential by 71.5%, while anaerobic digestion technology could reduce global warming potential by 92.7%. This study will offer scientific guidance for investment in anaerobic digestion and landfill gas to energy projects in China and other countries.
Keywords: Electricity generation potential | Organic fraction of municipal solid waste | Biogas | Landfill gas to energy technology | Anaerobic digestion technology | Global warming potential
مدیریت زباله های جامد شهری در طول شیوع SARS-COV-2 و سهولت قرنطینه: درس هایی از ایتالیا
سال انتشار: 2020 - تعداد صفحات فایل pdf انگلیسی: 6 - تعداد صفحات فایل doc فارسی: 19
ادبیات مربوط به زباله های جامد شهری در رابطه با COVID-19 کمیاب است. بر اساس تجربه ایتالیا، مقاله حاضر به استراتژی هایی با هدف جلوگیری از شیوع دوم ویروس کمک می کند. در واقع، سوء مدیریت زباله های جامد شهری می تواند استراتژی ها را در طول سهولت قرنطینه تضعیف کند. در طول شیوع SARS-COV-2 در ایتالیا، کاهش کلی در نرخ جمع آوری انتخابی وجود داشت (-15٪ در یک شهرداری با سیستم جمع آوری خانه به خانه به خوبی توسعه یافته). تأخیر در انتشار دستورالعملهای مدیریت پسماند بر ایمنی اپراتورهای جمعآوری زبالههای بالقوه آلوده تأثیر گذاشت. برخلاف انتظارات، ماسکها و دستکشهای یکبار مصرف تأثیر قابلتوجهی بر مدیریت پسماند. با این حال، پراکندگی ماسکها و دستکشهای رها شده در خارج از محیطهای داخلی باعث ایجاد مشکلات زیستمحیطی میشود. توصیه هایی در مورد مدیریت پسماند و حفاظت از اپراتورهای زباله مورد بحث قرار گرفته است. در نهایت، دستورالعمل هایی در مورد مناسب ترین تصفیه زباله از قبل ارسال و تجزیه و تحلیل شده است. نتایج ارائه شده در این مقاله نشان می دهد که بخش مدیریت MSW راه حل های مفیدی برای مقابله با COVID-19 پیدا کرده است. با این حال، این راه حل ها به اندازه کافی به اشتراک گذاشته نمی شوند. مطالعه موردی تحلیلشده در کار حاضر میتواند به تعریف استراتژیهایی برای پیشگیری یا کنترل اپیدمیهای مشابه یا دورههای همهگیر آینده کمک کند.
کلید واژه ها: کووید -19 | زباله جامد شهری | عفونت | امنیت شغلی | SARS-COV-2 | مجموعه انتخابی
|مقاله ترجمه شده|
Economic analysis of a shared municipal solid waste management facility in a metropolitan region
تجزیه و تحلیل اقتصادی از یک مرکز مدیریت زباله جامد شهری در یک منطقه شهری-2020
Municipal solid waste (MSW) management in dense urban areas is a challenge for municipalities, especially in developing countries, which commonly have deficient waste management. For example, the metropolitan region of Goiás State, Brazil, has 19 municipalities that dispose of about 72.5% of total MSW in unlicensed MSW final disposal facilities. Therefore, this study analysed the investment and operating costs, and revenues of a municipal solid waste management facility, projected for 20 years, shared among these 19 municipalities. The economic viability analysis, has shown that, regardless of the management facility type, MSW collection and transport are the most expensive cost components, accounting for about 60% of MSW management operating costs. For an Internal Rate of Return of 0%, anaerobic digestion is 11% more expensive (in total) than using community composting. For 2040 (last year), the monthly MSW management tariffs will vary between 3.5 and 10.8 R$inhabitant1month1, depending on the municipality. So, as the unit price of biowaste treatments lowers with waste quantities, for the municipalities with large biowaste quantities, anaerobic digestion becomes recommended for its economic attractiveness. This study can serve as a model for other municipalities in Brazil and elsewhere, helping public decision makers to establish a strategy for MSW management.
Keywords: Economic analysis | Municipal solid waste (MSW) | Shared management | Tariff | Brazil
Prediction of greenhouse gas emissions from Ontario’s solid waste landfills using fuzzy logic based model
پیش بینی انتشار گازهای گلخانه ای از محل های دفع زباله جامد انتاریو با استفاده از مدل مبتنی بر منطق فازی-2020
In this study, multi-criteria assessment technique is used to predict the methane generation from large municipal solid waste landfills in Ontario, Canada. Although a number of properties determine the gas generation from landfills, these parameters are linked with empirical relationships making it difficult to generate precise information concerning gas production. Moreover, available landfill data involve sources of uncertainty and are mostly insufficient. To fully characterize the chemistry of reaction and predict gas generation volumes from landfills, a fuzzy-based model is proposed having seven input parameters. Parameters were identified in a linguistic form and linked by 19 IF-THEN statements. When compared to measured values, results of the fuzzy based model showed good prediction of landfill gas generation rates. Also, when compared to other first order decay and second order decay models like LandGEM, the fuzzy based model showed better results. When plotting the LandGEM and Fuzzy model values to the actual measured data, the fuzzy model resulted in a better fit to actual data than the LandGEM model with a coefficient of determination R2 of 0.951 for fuzzy model versus 0.804 for LandGEM model. The results show how multi-criteria assessment technique can be used in modelling of complicated processes that take place within the landfills and somehow accurately predicting the landfill gas generation rate under different operating conditions
Keywords: Municipal solid waste | Landfill gas | Life-cycle assessment | Waste to energy | Greenhouse gas emissions | Fuzzy model
A municipal solid waste indicator for environmental impact: Assessment and identification of best management practices
شاخص ضایعات جامد شهری برای اثرات زیست محیطی : ارزیابی و شناسایی بهترین شیوه های مدیریت-2020
The objective of this study was to develop an aggregate indicator to assess the environmental impact of municipal solid waste management in the small municipalities of the state of S~ao Paulo, Brazil. Additionally, the study aimed at creating a classification of the municipalities considered to identify the best management practices. The study consisted of five phases: Phase 1: Selection of municipalities; Phase 2: Data collection (inputs); Phase 3: Use of the Waste Reduction Model; Phase 4: Analysis of results (outputs) and; Phase 5: Construction of the aggregate indicator and comparison between municipalities to analyze management practices. The results showed that the average waste generation was 223.89 kg (inhabitant1 year1), the average carbon dioxide equivalent (CO2e) emissions was 0.166 tons (inhabitant 1 year1), the average amount of energy savings was 51.37 kWh (inhabitant1 year1) and that most municipalities had suitable final waste destinations. After developing the aggregate indicator, which was a geometric mean of the normalized indicators for waste generation, emissions of CO2e, energy consumption and quality of final destination, the municipalities were ranked. Among the ten best-ranked municipalities, six of them disposed of the waste in municipal landfills, and four, in private landfills. Only one municipality is part of a consortium, while seven of them have institutionalized selective collection. One of the critical points for good indicators is the presence of waste pickers. For further improvements in the management of these municipalities, it is suggested that practices involving recycling and the integration of waste pickers with proper technical training are developed and implemented further. It is also recommended fostering greater social inclusion and integrated participation in the management of municipal solid waste. The aggregate indicator developed was regarded as appropriate to assess the environmental impact of municipalities and to classify them, allowing the identification of the best management practices.
Keywords: Indicators | Strategic waste management | Environmental analysis | Carbon dioxide equivalent
Anaerobic digestion based waste-to-energy technologies can halve the climate impact of China’s fast-growing food waste by 2040
هضم بی هوازی مبتنی بر فناوری های هدر دادن به انرژی می تواند تأثیر آب و هوای زباله های مواد غذایی سریع رشد چین را تا سال 2040 کاهش دهد-2020
Food waste (FW) has become a global sustainability challenge due partly to its signiﬁcant environmental impacts (e.g., greenhouse gas (GHG) emissions) from traditional treatment methodologies such as landﬁll and incineration. This is particularly the case for developing countries, for example over 90% of FW in China is currently blended with municipal solid waste and disposed of by landﬁlling and incin- eration. The anaerobic digestion (AD) technologies for energy recovery, however, has often been iden- tiﬁed as an effective approach for mitigating FW treatment related GHG emissions. In order to benchmark and quantify such reduction potentials, a dynamic model has been built to characterize the generation and ﬂow of FW and treatment associated GHG emissions in China from 2001 to 2040. Our results show that the total FW generation from household and catering sectors reached 170 ± 30 Mt in 2018 and will steadily increase to approximately 220 ± 42 Mt by 2040. Accordingly, the FW treatment related GHG emissions reached 137 ± 26 Mt CO2e in 2018 and would rise to approximately 180 Mt±33 CO2e by 2040 if waste management continues with the current pattern in a Business As Usual (BAU) scenario. Compared to the BAU scenario, the scenarios subject to AD technology implementation (from conservative to optimistic) could signiﬁcantly reduce GHG emissions and ensure a proportional contri- bution of this sector to China’s national emission reduction goal (55% by 2025 and 65% by 2030 compared to 2005). Speciﬁcally, a cumulative amount of approximately 1.9 Bt CO2e could be mitigated between 2019 and 2040 under the optimistic scenario (with 60%, 80%, and 80%, respectively, of household food waste, catering food waste, and waste cooking oil treated by AD). These ﬁndings could not only inform evidence-based policy making to facilitate the waste-to-energy development for FW treatment in China, but also shed light on the sustainable FW management and AD technology implementation in other developing countries.© 2020 Elsevier Ltd. All rights reserved.
Keywords: Food waste | Waste management | Greenhouse emissions | Climate change mitigation | Anaerobic digestion
Integrated water, waste and energy management systems : A case study from Curauma, Chile
سیستم های مدیریت یکپارچه آب ، زباله و انرژی: یک مطالعه موردی از Curauma ، شیلی-2020
The demand for energy and water by urban populations will increase in the next few decades, mainly due to migration of people. Enhanced living standards will also increase the demand for both resources. As both energy supply and water are limited, efficient use is a sine qua non for any future development of cities. This study elaborates the resource and environmental impacts of implementing an integrated water, waste and energy management system, using the medium-sized but rapidly growing settlement of Curauma, Chile, as a case study. The Integrated System is designed by separating wastewater at the source and mixing blackwater with organic municipal solid waste to generate electricity and heat by fermentation. By recycling greywater the demand for drinking water can be reduced. The analysed Integrated System could raise the share of renewables in the energy mix up to by 19% (electricity) and 51% (heat), and save fresh water resources by 30%. The depletion potential of the Integrated System regarding water, fossil and metal resources is notably lower (up to 52%) compared to the Conventional System. The same is true with respect to Climate Change, Freshwater Ecotoxicity, Freshwater Eutrophication and Human Toxicity: up to 45%. The impacts of the Integrated System related to Terrestrial Acidification are up to 174% higher due to emissions in the anaerobic digestion process, and heat and power generation with biogas.
Keywords: Water-energy nexus | Urban wastewater system | Organic municipal solid waste | Anaerobic digestion | Environmental assessment