1. Evaluation of an integrated food waste treatment strategy for Hong Kong with the potentials for reduced greenhouse gas production and increased energy recovery
- Author
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Chan, Richard Chung and Chan, Richard Chung
- Abstract
Food waste (FW) management is an important issue in Hong Kong. An alternative to the current management system is needed to achieve sustainable FW treatment. Food waste disposer (FWD) has been proven is proved viable to divert FW away from the solid waste treatment stream to the wastewater treatment stream. This study comprehensively investigated the impacts of the use of FWD on greenhouse gas (GHG) emission and energy recovery potentials. In the first phase of the study, household food waste (HFW) was sampled from three residential areas in Hong Kong and analyzed in the laboratory. Results showed little temporal and spatial variation in physical characteristics; however, large fluctuations in chemical characteristics were observed. Moreover, over 50% of COD, nitrogen and phosphorus were released into soluble phase after FWD treatment. The results of these analyses suggest that COD in HFW may have a much higher influence on WWTP effluent quality compared with nitrogen and phosphorus in HFW after the use of FWD. The results also indicated increase of COD/TN and COD/TN ratios which should facilitate the biological nutrient removal in biological wastewater treatment facilities. In the second phase of the study, based on the characteristics of local FW, a plant-wide steady state mathematical model was employed to comprehensively assess the potential overall impact of adding FW to the wastewater entering WWTPs. Given the combined influent characteristics of FW and WW, the effluent quality of WWTPs was not affected significantly in terms of COD and nitrogen. The use of FWD could produce substantial amounts of primary sludge and waste activated sludge in WWTPs. Methane production was dramatically improved with primary sludge as the main contributor. The surplus aeration required for treating the organic loading from the FW addition did, however, increase energy consumption. The overall energy balance was estimated to be positive with increased energy generation from the FW
- Published
- 2019