Biogas Potential for Improved Sustainability in Guangzhou, China—A Study Focusing on Food Waste on Xiaoguwei Island

Abstract

As a result of rapid development in China and the growth of megacities, large amounts of organic wastes are generated within relatively small areas. Part of these wastes can be used to produce biogas, not only to reduce waste-related problems, but also to provide renewable energy, recycle nutrients, and lower greenhouse gases and air polluting emissions. This article is focused on the conditions for biogas solutions in Guangzhou. It is based on a transdisciplinary project that integrates several approaches, for example, literature studies and lab analysis of food waste to estimate the food waste potential, interviews to learn about the socio-technical context and conditions, and life-cycle assessment to investigate the performance of different waste management scenarios involving biogas production. Xiaoguwei Island, with a population of about 250,000 people, was chosen as the area of study. The results show that there are significant food waste potentials on the island, and that all studied scenarios could contribute to a net reduction of greenhouse gas emissions. Several socio-technical barriers were identified, but it is expected that the forthcoming regulatory changes help to overcome some of them.

Effect of Organic Loading Rate and Temperature on the Anaerobic Digestion of Municipal Solid Waste: Process Performance and Energy Recovery

“…Related calculations involved in the preliminary energy analysis are shown in Figure 1, where C = specific heat of influent, which approximated to water, 4.18 KJ/(kg • C); V I = the flow volume fed to the digester per day; φ = the electricity energy used for pumping, 0.5 KWh/m 3 (Lu et al, 2008;Mu et al, 2018); ω = the electricity energy used for stirring, 0.08 KWh/(m 3 •d) (Lu et al, 2008;Mu et al, 2018); The material used for the designed reactor was 300 mm thick insulated concrete wall, U = heat transfer coefficient, 1.99 W/(m 2 • • C) (Liu et al, 2017a); A = superficial area of reactor, which was calculated according to the calculation formula, 1152 m 2 ; T 1 = ambient temperature, which is close the average annual temperature in China, 10.3 • C; T 2 = reactor temperature, 35 • C for mesophilic condition or 55 • C for thermophilic condition; The efficiency of the CHP in converting biogas into thermal and electricity energy were 33 and 50%, respectively (Feiz et al, 2019;Valentino et al, 2019), H M = calorific value of methane, 35.8 kJ/L (Chen et al, 2019), and V M = volume of methane produced.…”