Djavan De Clercq

Performance evaluation model of a pilot food waste collection system in Suzhou City, China

This paper analyses the food waste collection and transportation (C&T) system in a pilot project in Suzhou by using a novel performance evaluation method. The method employed to conduct this analysis involves a unified performance evaluation index containing qualitative and quantitative indicators applied to data from Suzhou City. Two major inefficiencies were identified: a) low system efficiency due to insufficient processing capacity of commercial food waste facilities; and b) low waste resource utilization due to low efficiency of manual sorting. The performance evaluation indicated that the pilot project collection systems strong points included strong economics, low environmental impact and low social impact. This study also shows that Suzhous integrated system has developed a comprehensive body of laws and clarified regulatory responsibilities for each of the various government departments to solve the problems of commercial food waste management. Based on Suzhous experience, perspectives and lessons can be drawn for other cities and areas where food waste management systems are in the planning stage, or are encountering operational problems.

Performance evaluation of restaurant food waste and biowaste to biogas pilot projects in China and implications for national policy

The objective of this research was to conduct a performance evaluation of three food waste/biowaste-to-biogas pilot projects across 7 scenarios in China based on multi-criteria decision analysis (MCDA) methodology. The projects ranked included a food waste-biogas project in Beijing, a food waste-biogas project in Suzhou and a co-digestion project producing biomethane in Hainan. The projects were ranked from best to worst based on technical, economic and environmental criteria under the MCDA framework. The results demonstrated that some projects are encountering operational problems. Based on these findings, six national policy recommendations were provided: (1) shift away from capital investment subsidies to performance-based subsidies; (2) re-design feed in tariffs; (3) promote bio-methane and project clustering; (4) improve collection efficiency by incentivizing FW producers to direct waste to biogas projects; (5) incentivize biogas projects to produce multiple outputs; (6) incentivize food waste-based projects to co-digest food waste with other substrates for higher gas output.

Design, implementation, and evaluation of an Internet of Things (IoT) network system for restaurant food waste management

Catering companies around the world generate tremendous amounts of waste; those in China are no exception. The paper discusses the design, implementation, and evaluation of a sensor-based Internet of Things (IoT) network technology for improving the management of restaurant food waste (RFW) in the city of Suzhou, China. This IoT-based system encompasses the generation, collection, transportation and final disposal of RFW. The Suzhou case study comprised four steps: (1) examination of the required functionality of an IoT-enabled system in the specific context of Suzhou; (2) configuration of the system architecture, both software and hardware components, according to the identified functionality; (3) installation of the components of the IoT system at the facilities of the stakeholders across the RFW generation-collection-transportation-disposal value chain; and (4) evaluation of the performance of the entire system, based on data from three years of operation. The results show that the system had a strong impact. Positive results include: (1) better management of RFW generation, as evidenced by a 20.5% increase in RFW collected via official channels and a 207% increase in the number of RFW generators under official contract; (2) better law enforcement in response to RFW malpractice, enabled by the monitoring capabilities of the IoT system; and (3) an overall reduction in illicit RFW activities and better process optimization across the RFW value chain. Negative results include: (1) Radio-frequency identification (RFID) tags need to be renewed often due to the frequent handling of waste bins, thus increasing operating costs; (2) dynamic/automatic weight sensors had a higher degree of error than the more time-consuming static/manual weighing method; and (3) there were disagreements between the citys government agencies about how to interpret data from the IoT system, which led to some inefficiencies in management. In sum, the Suzhou IoT system enabled data-driven management of RFW and had a net positive impact for the stakeholders involved.

Transforming the Cement Industry into a Key Environmental Infrastructure for Urban Ecosystem: A Case Study of an Industrial City in China

Under the dual pressure of environmental constraints and increasingly thin profit margins, the cement industry in China is in a predicament. To alleviate the environmental and the economic pressure of the cement industry and to tackle the problem of delayed environmental infrastructure construction, this article introduced an urban ecosystem in which the cement industry was transformed into an effective complement to environmental infrastructure. The Xinfeng Cement Industrial Park in China, which has a production capacity of 5 million tonnes per annum (Mt/a) of clinker, was chosen as a case study. Our methodology involved proposing technologies to develop an efficient cement plant‐centered urban ecosystem; evaluating its environmental and economic performance; identifying barriers in its promotion; and proposing supportive policies. Results showed that the citys waste recycling ratio rose from about 50% to 70%, saving 0.6 Mt/a of coal equivalent and reducing about 3.0 Mt/a of resulting carbon dioxide (CO2) emissions. The life span of the citys landfill site was extended by about 30 years. The total investment was 3.2 billion yuan (about US

Effect of initial bulk density on high-solids anaerobic digestion of MSW: General mechanism

480 million),1 with an average payback period of 3 years. The Xinfeng Cement Industrial Park was transformed from an energy‐intensive consumer and a significant CO2 emitter to a key industrial waste recycler, a crucial municipal waste co‐processor, an important new building material supplier, and a potential energy producer. Last, the “not‐in‐my‐back‐yard” (NIMBY) effect from constructing new environmental infrastructure was also avoided.

Biomethane production potential from restaurant food waste in megacities and project level-bottlenecks: A case study in Beijing

Initial bulk density (IBD) is an important variable in anaerobic digestion since it defines and optimizes the treatment capacity of a system. This study reveals the mechanism on how IBD might affect anaerobic digestion of waste. Four different IBD values: D1 (500-700kgm-3), D2 (900-1000kgm-3), D3 (1100-1200kgm-3) and D4 (1200-1400kgm-3) were set and tested over a period of 90days in simulated landfill reactors. The main variables affected by the IBD are the methane generation, saturation degree, extraction of organic matter, and the total population of methanogens. The study identified that IBD >1000kgm-3 may have significant effect on methane generation, either prolonging the lag time or completely inhibiting the process. This study provides a new understanding of the anaerobic digestion process in saturated high-solids systems.