Analysis And Control Of Nutrients And Organic Pollutants In Typicial Rivers Inpouring Into Maritime Space In Tianjin

This is a part of 973 Program, which is to find the method of controlling complex pollution and the principle of repairing the typical damaged ecosystem. The nitrogen, phosphorus and organic pollutants distribution in water and sediment in the typical rivers inpouring into maritime space in Tianjin is mainly studied, and the control method is put forward.The main cause of the pollution of Bohai Sea alongshore area is the land source pllutants, and one of the main land source pollutants inporing into sea is the pollutants from rivers. Therefore, it is significative to do the research of the pollution of rivers around Bohai sea.After detailed analysis, the Dagu drainage river and Beitang drainage river are selected to be the study object. The envitonmental status including geography conditions and pollution sources is introduced. The results show that point sources are the main pollution sources, and that industrial wastewater and domestic sewage are the main point sources. The key to control the main piont sources is found.After field survey, according to the sampling principle, reasonable sampling sections are selected, and the testing is done in flood period, usual discharge period and drought period. The monitoring indexes include temperature, pH, turbidity, NH3-N, TN, TP and CODCr. According to the the water quality monitoring results, the temporal and spatial distribution of pollutants in the two rivers is analyzed, and the assessment of water quality is made by using improved Principal Component Analysis and Nemero Index assessment method. The results show that nearly all the pollutants are over standard, that the main pollutant is COD, that the effect of phosphorus is relatively not important, and that the most polluted areas are around Dagu drainage river bridge, Jingjiang bridge and the area where the Beitang river converge to the gate of Yongdingxin river. Since the main pollutants are the same in different water period, the method of controlling pollution from sources is put forward. Since the most polluted area is not the same in different water period, the selective control at the key positions should be done in different water period.After the analysis of correlation, it is found that the monitoring indexes in water may have significant correlation with one or more other indexes. Therefore, a monovatiant linear regression model is made to predict the concentration of NH3-N in Beitang drainage river. Significance test, residuals analysis and influence measures is done for the model, and practical data is used to validate the model. It is proved that the model is credible and useful.By the method of sampling layered sediment and testing, the temporal and spatial distribution characteristics of pollutants in sediment is discussed. The results showed that pollutants in water can accumulate into the sediment, and pollutants in sediment show an uneven distribution. Thus, the polluting charactristic between years can be analyzed combining with historic data. It is proved that sampling layered sediment is very useful.