典型城镇污水处理工艺的环境影响评价研究

Environmental integrated assessment of typical urban sewage treatment process

污水处理过程中消耗大量的能源和水处理药剂,会对环境产生一定的影响。随着污水排放标准的日趋严格和污水处理工艺的提质升级,污水处理厂对环境的影响发生了巨大变化。识别污水处理过程中的主要环境影响类型有利于环境的保护。文章采用生命周期评价与生命周期成本分析相结合的评价方式,对山东济宁某污水厂运行阶段的环境影响和经济成本进行了分析与评价。研究结果表明:污水处理在气候变化、陆地酸性化、淡水水体富营养化、人类毒性、光化学氧化剂形成、颗粒物形成、淡水生态毒性、海洋生态毒性、自然土地改造、化石能源消耗等10个方面对环境影响较大;污水处理过程中,关键流程为生物处理阶段和深度处理阶段;关键物质为电力和净水剂聚合氯化铝,而两种关键物质环境影响潜值占比分别达到了总值的58.3%和39.0%。

A large amount of energy and chemicals are consumed in the process of sewage treatment,which leads to negative environmental impacts. With the increase of sewage discharge standards and upgrading of sewage treatment processes,the environmental impact of sewage treatment plants has changed dramatically compared with before. In this paper,the environmental impact and economic cost of a sewage treatment plant in Jining City,Shandong Province are analyzed and evaluated by the integrated LCA and LCC. The results show that the sewage treatment plant has larger environmental impact in the following 10 categories, i. e. climate change, terrestrial acidification, freshwater eutrophication, human toxicity, photochemical oxidant formation, particulate matter formation,freshwater ecotoxicity,marine ecotoxicity,natural land transformation and fossil depletion. The key processes of sewage treatment are biological treatment stage and advanced treatment stage. The key substances are power and PAC,which contribute 58. 3% and 39. 0% to the total environmental impact,respectively.