日本分散型生活污水处理技术与设施建设状况分析

Analysis of Decentralized Domestic Sewage Treatment Technologies and Facilities in Japan

日本的生活污水处理是由下水道事业(指城市污水处理厂及管网建设)、农业村落污水处理事业以及净化槽事业构成。其中农业村落污水处理事业以及净化槽事业面向农村等人口密度较小区域,以分散型生活污水处理为基本处理模式。下水道事业长久以来是以大城市下水道的建设为中心发展而来,近年来地方城市等小规模的下水道建设得到全面推进。然而日本的湖泊及内海等封闭型水域的富营养化问题日益严重,水环境的改善趋势长期得不到认可,为此面向分散型生活污水的深度处理技术也得到了发展与推广。基于日本的公开资料,通过相关技术发展状况的分析调查,结果表明,日本采用的主要深度处理技术分为间歇曝气工艺、深度处理氧化沟工艺、膜分离活性污泥工艺,这三种工艺均由生物脱氮与絮凝沉淀除磷单元组合而成,被积极应用于农业村落污水处理事业中。

Japan＇ s domestic wastewater treatment works consists of the sewage treatment pro- grams, the rural community wastewater treatment programs and the household （on-site） treatment pro- grams. The rural community wastewater treatment programs and household treatment programs are imple- mented primarily for scarcely populated areas such as farm villages to provide services based on decentral- ized-type treatment systems for domestic wastewater. Historically, the sewage treatment programs focused primarily on the development of large-scale sewage systems in urban areas; however, in recent years, more effort has been put into the development of small-scale sewage systems in provincial towns and cit- ies. Further, some lakes and inner bays have been experiencing an eutrophication problem in which their water quality has been deteriorating over a long period of time, and their situations have not yet been im- proved. As an effort to cope with these situations, advanced treatment technologies have been introduced into these decentralized domestic wastewater treatment systems. The technological trends in this area were analyzed based on the relevant data published in Japan. The results showed that the main technologies used in Japan could be categorized roughly into three types： （1） the intermittent aeration activated sludge process; （2） the advanced oxidation ditch process; and （3） the membrane separation activated sludge process. All of these three types of processes, which combine a biological nitrogen removal process and a phosphorus removal process utilizing a coagulation sedimentation method, have been actively introduced into the rural community wastewater treatment programs.