Study On Advanced River Water Purification Technology And Its Demonstration Projects In Tongzhou Period Of North Canal

With the development of society and economy, the water quality of North Canal water in Tongzhou district deteriorated continuously. Presently, the water body has been defined as the black and odorous river water with its water quality beyond class V.According to water quality monitoring records, there are three sewage outlets on the east of Eastern Chemical Plant discharge sewage into the North Canal in Tongzhou district. The pollutant concentration of their discharging sewage is at the highest level among the North Canal basin, which most severely affects the water quality. Therefore, in order to study the construction of purification system and repair water quality of the North Canal in Tongzhou district, this paper takes the high concentration wastewater and contaminated river water as process objects in view of the main pollutant composition, removal of the load and advantages of all kinds of processing to analysis and putting forward the application of integrated process systems combined with purification technologies of physical chemistry and biochemistry and carrying out the water treatment technology research. Through researches on electrochemical biofilter, new bio-immobilized MBR and BAF technology to built an efficient unit-assembling technology system for urban landscape water body and establish a demonstration project.In order to solve the problem of high-carbon and high-nitrogen concentration sewage into the river, single-stage and two-stage high efficient BAF would be designed. The results from BAF wastewater treatment experiment showed that the water quality of effluent meets the requirements of the First Grade B of "Discharge standard of pollutants for municipal wastewater treatment plant" (GB18918-2002)3 Experimental studies have been applied on the purification of contaminated surface water by the condition of Q=10L/h, which are MBR combined process, O3-BAC process and electrochemical process. The concentration ranges and removal rates were analyzed during operation. The effluent water quality from MBR combined process and O3-BAC process are better than that from electrochemical process, however, the electrochemical process system has a high removal rate of TN, reaching 54%. The results of comparing the process and economic systems of MBR combined process and O3-BAC process show that the cost of sewage disposal per ton by the former process was 1.06 yuan more than the later one. There is little difference on purifying effect between the two purification processes, but the later has a better removal rate for CODCr The optimum process is O3-BAC for advanced treatment of canal water quality considering the water quality characteristics including huge quantity, low biodegradability and difficulty of organics removal.BAF+ and O3-BAC have been used integrally to purify contaminated water in North Canal. The stable operation results of the integrated process under optimal conditions of the system show that the average removal rates of CODCr, NH3-N and TN were 61%,96% and 19% respectively. The average concentration in the effluent were 35.7 mg/L,0.63mg/L and 14.6mg/L respectively, which reached the standard of ornamental river water quality in the " The reuse of urban recycling water — Water quality standard for scenic environment use"(GB/T 1892—2002), each unit of the integrated process system is contribution to the removal of contaminants.Results of above research in this study provide technical support for advanced river water purification technology research and demonstration projects of North Canal in Tongzhou City (the operation scale is 30,000 m3/d). Assessments have been made on water quality monitoring of inflow and outflow after 3-year-long stabile operation of the demonstration projects. The results showed that by imploying the integrated process system the major pollutants can be curbed efficiently from discharging into the river, and meanwhile a large amount of river water had been treated, which can consequently provide necessary water for forest park. And therefore, it is worthy of being further generalized in the fure.