The Study Of Water Quality And Pollution Control Of Southwest Tidal River

Environmental governance of tidal river is an important river pollution problem to be solved, because its flow characteristics are different from ordinary river. Tidal river flow caused by the reciprocating motion, making it difficult to diffusion of water pollutants, increase water pollution. Therefore, the characteristics of typical tidal river water pollution and pollution remediation technology has important theoretical and practical significance.In this paper, Southwest tidal river in Foshan City is a typical tidal river. The tidal river water quality indicators had been investigated and analyzed, in order to make a comprehensive and detailed analysis of the point source and non-point source pollutants and to establish major pollutants control models of COD, ammonia nitrogen and total phosphorus reduction discharge and to-calculate control targets of major pollutants emissions and predict water quality status.Firstly, the main source of pollutants in six branch rivers of Southwest tidal river had studied, in order to analyze water quality contaminants index of branch river at high tide and low tide on temperature, dissolved oxygen, pH value, COD, BOD, ammonia nitrogen, total phosphorus, oil, etc.,The paper also had monitored and compared with section water quality of Sanshui Southwest Gate, Middle Fenggang, Heshun End. The results showed that the water quality in Lubao Chung reach IV class, other five branches (Damian Chung, Dalangwo Chung, Zuoan Chung, Jiefang Chung, Leping Chung) are V class; Southwest Tidal River entrance stream reach Ⅲ class, mid-stream reach the inferior to V class, exit stream reach class V.The water quality analysis of the monitoring sections showed that the water quality of Southwest Tidal River was contaminated and did not meet the basic requirements of water function planning. It also showed that the branch rivers were polluted seriously and the water quality of all the branch rivers was inferior to V class. The results of survey and calculation showed that the total amounts of agricultural non-point source pollutants excessed the total amount of point sources pollutants of industrial production and domestic pollution. The non-pointsource emissions of COD was basically the same as the point source emissions, but the emissions of ammonia nitrogen and total phosphorus of non-pointsource was 2.7 times and 6 times as the point source emissions. It showed that the key issues of the tidal river pollution were ammonia nitrogen and total phosphorus pollution.The linear regressions of non-point source and point source emissions of the main branch rivers are studied and obtained. The calculation formula of total pollutants amount which was the relationship between the amount of point source emissions and non-point source emissions. The regression equation of COD was Y=0.6613X1+0.9899X2-79.5665, the regression equation of ammonia was Y=0.523X1+0.5763X2+4.4474 and the regression equation of total phosphorus was Y=1.4399X1+0.7905X2-4.8306.The pollution remediation should focus on branch rivers, especially the pollution control of ammonia nitrogen and total phosphorus.The mainly pollution control measures of point source pollution were strengthening the construction of sewage collection pipe network, and expediting the construction of sewage treatment plants.The mainly pollution control measures of ammonia nitrogen and total phosphorus were controlling agricultural non-point source pollution comprehensively, strengthening the management of livestock breeding, using pesticides and fertilizers scientifically and rationally, establishing the ban area in a certain distance near the tidal river.