Waste-to-Energy (WtE) has gradually constituted one of the most important options to achieve energy recovery from municipal solid waste (MSW). However, the environmental sustainability of a specific WtE system varies with used technologies and geographic differences. As a result, three representative WtE systems are compared using life cycle assessment (LCA): a gasification-based WtE plant in Finland, mechanical-grate incineration in France, and circulating fluidized bed incineration in China. Results show that the overall environmental performance of the gasification system is better than incineration. The use of gasification technology, attributed to an intermediate syngas purification step, can provide benefits of both reducing the stack emissions and increasing the energy efficiency. Regional waste management, especially related to MSW caloric value and emission regulation, are determining factors for a preferable performance of the incineration in France over that in China. Sensitivity and uncertainty analyses further address key variations such as choice of MSW composition, basis of displaced electricity, energy recovery mode, and application of "best-available technology" dedicated to incineration. It is found that the most sensitive parameters influencing the LCA results are: electricity recovery, CO 2 emission, and NO x emission. In the future, use of the source-separated high caloric waste combined with a more stringent emission standard can efficiently improve MSW incineration in China. Bottom ash recycling for metals and materials is highly applicable regarding incineration in France. This presented study can overall contribute to the development of specific WtE technology and local waste management plan for decision-makers.
This article proposes a comprehensive review of evaluation tools based on life cycle thinking, as applied to waste-to-energy. Habitually, life cycle assessment is adopted to assess environmental burdens associated with waste-to-energy initiatives. Based on this framework, several extension methods have been developed to focus on specific aspects: Exergetic life cycle assessment for reducing resource depletion, life cycle costing for evaluating its economic burden, and social life cycle assessment for recording its social impacts. Additionally, the environment-energy-economy model integrates both life cycle assessment and life cycle costing methods and judges simultaneously these three features for sustainable waste-to-energy conversion. Life cycle assessment is sufficiently developed on waste-to-energy with concrete data inventory and sensitivity analysis, although the data and model uncertainty are unavoidable. Compared with life cycle assessment, only a few evaluations are conducted to waste-to-energy techniques by using extension methods and its methodology and application need to be further developed. Finally, this article succinctly summarises some recommendations for further research.
There is a significant increase in the volume of Municipal Solid Waste (MSW) that is being generated across the world. Faced with this challenge and the associated environmental issues, MSW management (MSWM) in Hangzhou, China has made various positive changes in order to adapt. During the last 10 years, MSW source-separated collection was launched, which was accompanied by estimations of a new waste-to-energy (incineration) plant and food waste separate treatment methods. The aim of this study is to investigate the related evolution of the environmental performance of MSWM system in Hangzhou from 2007 to 2016 by using life cycle assessment (LCA). LCA is a scientific tool to quantify factors such as environmental impacts from a life cycle perspective and provides valuable inputs to decision-makers, thus leading to proper strategy determination. Results illustrate that the annual environmental performance has an overall downward trend with some minor fluctuations. The MSWM system in 2010 had the lowest weighted result of 0.0349 PE/t-MSW due to the highest incineration rate and implementation of source-separated collection. Incineration shows better environmental performance than landfill, while source-separated collection can benefit the MSWM. While the importance of source-separated collection is significant, it is also essential to concentrate on the food waste treatment technology. It is suggested that anaerobic digestion (AD) can be considered as a primary option for food waste treatment.
Due to the problems of municipal solid waste (MSW) during the expanding urbanization, strategy to find an environmentally friendly, energy efficient, cost-effective, and socially acceptable MSW management system is essential for sustainable development. This study establishes a novel environment-energyeconomy-society (3E þ S) model from a life cycle perspective for sustainability assessment: life cycle assessment for evaluating environmental performance and energy consumption, life cycle costing for recording economic burden, and social life cycle assessment for reflecting social impacts; based on the individual 3E þ S results, the final ranking of alternatives is obtained by multi-criteria decision making, which is integrated with analytic hierarchy process and entropy weight method. This model is implemented to identify a sustainable MSW management system among four typical treatment alternatives. Results show that incineration with fluidized bed furnace is the best choice in this study; incineration with moving grate furnace follows after with a slight gap; landfill with and without energy recovery rank the third and the last. The framework of SLCA on MSW field is built in this study and sensitivity analysis is provided for further discussion on social impacts. The calculation method of weight factors reduces man-made disturbances and the sensitivity analysis demonstrates strong robustness of the results and effectiveness of the modification for the model.
With the aim of optimizing gasification systems, air gasification using simulated municipal solid waste is experimentally investigated in a fluidized-bed reactor. Process parameters considered include equivalence ratio (ER) and temperature. On the basis of the experimental results, energy and exergy analyses are performed to assess the thermodynamic quality. Results reveal that the energy and exergy contents of the produced gas increase first with rising temperature and then decline when the temperature exceeds 650°C. With regard to the ER, a similar tendency is observed with a peak value at an ER of 0.4. The energy content of the produced gas is much higher than its exergy content as a result of the remarkable difference between physical energy and exergy contents of sensible heat. The maximum chemical energy efficiency, total energy efficiency, chemical exergy efficiency, and total exergy efficiency of the products at the gasifier exit are attained at an ER of 0.4 and a temperature of 650°C, with values of 49.73, 64.05, 47.14, and 51.33%, respectively. The total exergy efficiency is suggested as an effective parameter to evaluate the properties of gasification-based thermal systems, because it expresses the availability of the products from the "first-step" gasifier for subsequent conversion.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.