关键词: 家庭厨余垃圾, 资源化, 提油, 厌氧消化, 沼液处理, 运营安全, 经济性分析

Abstract: Wet waste includes restaurant food waste and household kitchen waste. The existing wet waste anaerobic resource treatment project has an oil extraction process for restaurant food waste, but not for household kitchen waste. Based on a wet waste anaerobic resource utilization project in Shanghai, the impact of engineering operations safety before and after setting up oil extraction processes for household kitchen waste were analyzed, including the operational safety of anaerobic biological systems (which could be reflected by observing the changes in volatile fatty acids, alkalinity and the oil content of the biogas liquid), and operation safety of aerobic biological treatment system for biogas slurry (which could be reflected by the changes in dissolved oxygen). Analysis showed that the oil content in kitchen waste slurry was approximately 1.5%-3.0%,which was necessary to add an oil extraction process, otherwise, it would lead to an increase in volatile fatty acids and a decrease in alkalinity in the anaerobic system, making the system unsafe. The high oil content in the biogas slurry seriously affected the oxygenation effect of the sewage treatment system, and the dissolved oxygen in MBR system nitrification tank was below 0.5 mg/L, resulting in poor treatment efficiency and even the possibility of the biological system collapsing. The economic analysis indicated that the unit price of crude oil (based on waste) ranged from 4 000 to 8 000 yuan per ton. Considering both the income from crude oil and the operating costs, the revenue per ton of waste was 37.20-94.20 yuan. The methane production rate increased by approximately 12%. The frequency of ultrafiltration membrane contamination in the biogas liquid MBR treatment system decreased by approximately 40%. The research could provide references for the engineering design and operation of new or renovated projects of this type.

Key words: household kitchen waste, resource utilization, oil extraction, anaerobic digestion, biogas slurry treatment, operational safety, economic analysis