Design Of Water Quality Improvement Project For A City's Inland River

Zhejiang Province has developed economy and many rivers and lakes,but the ecological environment of rivers and lakes has been damaged for a time,which can not meet the growing needs of the people for beautiful ecological environment.Urban inland river is an important ecological corridor,which plays an indispensable role in urban ecosystem.The comprehensive renovation project of urban inland river is an important means to improve the quality of water ecological environment,including the improvement of river water quality,ecological restoration,wastewater interception and management.A river course in Linping street,Yuhang District,Hangzhou City,with a total length of about 1.1km,is located in the old urban area of Linping.The river course passes through many government buildings such as Yuhang District People's government,Yuhang District Cultural Center,Yuhang District Health Bureau,many hotels such as chuanfulou Hotel,Zhongqiang Holiday Hotel and apartments in the district.The river course is an underground river,and the area passing by is mainly the busy section of the street,which is not suitable for placing large-scale equipment.The construction progress of the surrounding sewage pipe network is slow,which leads to the direct discharge of domestic sewage into the river,making the construction difficult.At present,the indexes of ammonia nitrogen and total phosphorus in the river are higher than the class V standard of surface water,and the water quality is poor.In this paper,the engineering design for the improvement of water quality of the river course is carried out,and the requirements of five water co governance in Zhejiang Province are integrated.The governance objectives of the project are:two indicators of ammonia nitrogen and total phosphorus,which need to meet the class V water quality requirements in the environmental quality standard for surface water(GB3838-2002).Based on the field investigation and data collection and analysis,according to the characteristics of the underground river in this river channel,such as unsuitable for in-situ installation,unsuitable for large-scale equipment,difficult construction and direct discharge of domestic sewage,the treatment schemes of A~2/O,bardenpho,uct,microbial enhancement,high-efficiency chemical phosphorus removal,super magnetic separation technology,etc.are compared and analyzed,and 1set of 5000 is decided to be adopted m~3/d"super magnetic+microbial enhanced treatment system"deals with total phosphorus and ammonia nitrogen.The design has the characteristics of compact structure,small floor area,high treatment efficiency,and can better adapt to the actual situation of the river.According to the monitoring results of the project effluent,after a period of operation,the effluent ammonia nitrogen and total phosphorus indexes of the project meet the class V water quality requirements in the environmental quality standard for surface water(GB3838-2002).The removal efficiency of the whole set of equipment is 89.3%?97.9%for ammonia nitrogen and 84.1%?94.8%for total phosphorus,reaching the design efficiency,and the effluent water quality is stable,with good ecological value.