Introducing a classification framework to urban waste policy: Analysis of sixteen zero-waste cities in China

An MFA-LCA framework for goal-oriented waste management studies: 'Zero Waste to Landfill' strategies for institutions

Institutions such as university communities can be considered miniature versions of the larger society in which they exist. Nonetheless even though it should be easier to manage waste at an institution, their waste management (WM) programmes are typically lack an overall goal for improving environmental impact and are not optimally structured or operated. In part this is due to a lack of a framework that promotes a goal-oriented WM strategy. For instance, zero waste (ZW) to landfill studies have gained prominence in recent years, but generally there is a lack of clear guidance on how to carry out ZW strategies effectively at either, municipal or institutional levels. To fill this gap, this study aims to provide a framework that enables institutions to develop a goal-oriented WM strategy applying the principles of material flow analysis and life cycle assessment. The framework assumes that no prior data are available, and a study will therefore begin by collecting primary data followed by secondary data. The case study is presented in this article, along with the introduction of the framework, using ZW management scenarios in the Istanbul Technical University Ayazağa Campus. The results of the case study show that, it is not possible to achieve ZW to landfill on university campuses. And simply diverting waste from landfill (min 74% to max ~100%) does not necessarily lead to circularity (min 20% to max ~66%) or directly address public attitudes towards ZW goals.

Decreasing Greenhouse Gas Emissions from the Municipal Solid Waste Sector in Chinese Cites

Municipal solid waste (MSW) management systems play a crucial role in greenhouse gas (GHG) emissions in China. Although the government has implemented many policies to improve the MSW management system, the impact of these improvements on city-level GHG emission reduction remains largely unexplored. This study conducted a comprehensive analysis of both direct and downstream GHG emissions from the MSW sector, encompassing sanitary landfill, dump, incineration, and biological treatment, across 352 Chinese cities from 2001 to 2021 by adopting inventory methods recommended by the Intergovernmental Panel on Climate Change (IPCC). The results reveal that (1) GHG emissions from the MSW sector in China peaked at 70.6 Tg of CO2 equiv in 2018, followed by a significant decline to 47.6 Tg of CO2 equiv in 2021, (2) cities with the highest GHG emission reduction benefits in the MSW sector were historical emission hotspots over the past 2 decades, and (3) with the potential achievement of zero-landfilling policy by 2030, an additional reduction of 203.7 Tg of CO2 equiv is projected, with the emission reduction focus toward cities in South China (21.9%), Northeast China (17.8%), and Southwest China (17.3%). This study highlights that, even without explicit emission reduction targets for the MSW sector, the improvements of this sector have significantly reduced GHG emissions in China.

A review of the influence of heat drying, alkaline treatment, and composting on biosolids characteristics and their impacts on nitrogen dynamics in biosolids-amended soils

Application of biosolids to agricultural land has gained increasing attention due to their rich nutrient content. There are a variety of treatment processes for converting sewage sludge to biosolids. Different treatment processes can change the physicochemical properties of the raw sewage sludge and affect the dynamics of nutrient release in biosolids-amended soils. This paper reviews heat drying, alkaline treatment, and composting as biosolids treatment processes and discusses the effects of these treatments on biosolid nitrogen (N) content and availability. Most N in the biosolids remain in organic forms, regardless of biosolids treatment type but considerable variation exists in the mean values of total N and mineralizable N across different types of biosolids. The highest mean total N content was recorded in heat-dried biosolids (HDB) (4.92%), followed by composted biosolids (CB) (2.25%) and alkaline-treated biosolids (ATB) (2.14%). The mean mineralizable N value was similar between HDB and ATB, with a broader range of mineralizable N in ATB. The lowest N availability was observed in CB. Although many models have been extensively studied for predicting potential N mineralization in soils amended with organic amendments, limited research has attempted to model soil N mineralization following biosolids application. With biosolids being a popular, economical, and eco-friendly alternative to chemical N-fertilizers, understanding biosolids treatment effects on biosolids properties is important for developing a sound biosolids management system. Moreover, modeling N mineralization in biosolids-amended soils is essential for the adoption of sustainable farming practices that maximize the agronomic value of all types of biosolids.