Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, School of Energy and Environment, Southeast University, Nanjing, 210096, China.
Shenzhen Energy Environment Co., Ltd, Shenzhen, 518000, China.
Environ Sci Pollut Res Int. 2023 Apr;30(19):56303-56316. doi: 10.1007/s11356-023-26214-y. Epub 2023 Mar 14.
Anaerobic digestion is one of the most promising methods for reducing sewage sludge and recovering energy. In the present study, a comparative life cycle assessment (LCA) of sewage sludge anaerobic digestion processes with different digestate treatments, including mesophilic anaerobic digestion with digestate landfilling (CAD-1) and digestate incineration (CAD-2), thermophilic anaerobic digestion combined with thermal hydrolysis pre-treatment with digestate land use (THPAD-1), and digestate incineration (THPAD-2), was performed to evaluate their environmental, resource, economic, and comprehensive performances using the SimaPro software. Environmental impact analysis revealed marine ecotoxicity, freshwater ecotoxicity, and human carcinogenic toxicity as the most obvious impacts, resulting in the most significant damage to human health. Resource analysis indicated that anaerobic digestion combined with cogeneration and digestate incineration is advantageous to high energy recovery, but digestate incineration is disadvantageous to economic performance because of increased investment costs. Comparison of the four processes revealed that THPAD-2 results in the largest environmental damage, whereas CAD-1 has the smallest load. Meanwhile, THPAD-2 and THPAD-1 exhibit the best resource performance and net economic benefit, respectively. The comprehensive evaluation indices revealed that THPAD-1 and CAD-2 show better comprehensive performance. And the deep drying incineration process exhibited better comprehensive performance than sewage sludge anaerobic digestion processes.
厌氧消化是减少污水污泥和回收能源的最有前途的方法之一。在本研究中，采用 SimaPro 软件对不同沼渣处理的污水污泥厌氧消化工艺（包括中温厌氧消化与沼渣土地填埋（CAD-1）和沼渣焚烧（CAD-2）、高温厌氧消化与热解预处理联合沼渣土地利用（THPAD-1）和沼渣焚烧（THPAD-2））进行了比较生命周期评估（LCA），以评估它们的环境、资源、经济和综合性能。环境影响分析表明，海洋生态毒性、淡水生态毒性和人类致癌毒性是最明显的影响，对人类健康造成的损害最大。资源分析表明，厌氧消化与热电联产和沼渣焚烧相结合有利于高能回收，但由于投资成本增加，沼渣焚烧不利于经济性能。对这四种工艺的比较表明，THPAD-2 造成的环境破坏最大，而 CAD-1 的负荷最小。同时，THPAD-2 和 THPAD-1 分别表现出最好的资源性能和净经济效益。综合评价指标表明，THPAD-1 和 CAD-2 表现出更好的综合性能。深度干燥焚烧工艺的综合性能优于污水污泥厌氧消化工艺。
