THE DEVELOPMENT AND APPLICATION OF CHEMICALLY AND BIOLOGICALLY ENHANCED PRIMARY TREATMENT PROCESS FOR MUNICIPAL WASTEWATER TREATMENT

There are more and more professionals in China paying attention to the enhanced primary treatment technologies since a number of wastewater treatment plants are constructed by stages and the financial resources are limited. The biologically enhanced primary treatment (BEPT) process has been widely used to enhance the removal of the SS, COD and BOD5 in eastern and northern coastal cities of China in recent decade, most of them following a secondary biological treatment. This paper presents some of the research and test results in Tai'an and Qingdao City.On the other hand, the municipal wastewaters in China are typically characterized with low C/N and BOD/TP ratio, and the performance of biological phosphorus and nitrogen removal processes are difficult to meet the national and local treatment requirements for the weak and super weak municipal wastewater (BOD5 about 120 mg/L and 60 mg/L respectively). It means the chemical phosphorus removal is normally needed. And then, the chemically enhanced primary treatment (CEPT) process was introduced into China and put into practice in late 1990's.Based on research and engineering application of BEPT and CEPT processes, the Chemically and Biologically Enhanced Primary Treatment (CBEPT) process was developed by combining the BEPT and CEPT technology to improve the treatment performance and reduce the costs. This paper mainly focus on development and application research of this patented CBEPT process, and presents a brief discussion on the design of Shanghai Zhuyuan WWTP with capacity of 1.7 million m3/day which adopted this process and plan to put into operation in 2003.