Study Ofrural Disorderly Discharge Wastewater Pollution Characteristics And Its Impact Factors

The pollution to receiving waterbody caused by rural disorderly discharge wastewater has received more and more attention.In order to provide a theoretical basis for rural disorderly discharge wastewater control technology, thepollution characteristics and its impact factorsof rural disorderly discharge wastewater was studiedby monitoring,analyzing and studying the runoff pollutant concentrations of different underlying surfacesin the village of Fangqian of the town of Dingshu and the village of Sha tang gang of the town of Zhoutie, then taked a representative catchmentin the village of Fangqian asa researchsubject to builda dynamic water quantity and quality rural rainfall runoff pollution model, finally studied the impacts ofrural rainfall runoff on a receiving waterbody in the village of Hou he of the town of Dingshu. The main conclusionsare as follows:(1)A11 tested pollution indicators of private plots rainfall runoffare the biggest,its average concentrations ofSS、COD、TN、TP is 373.21mg/L,84.65mg/L,8.94mg/L,2.48mg/Lrespectively.The distribution of nitrogen and phosphorus of rural rainfall runoffindicate that TN is dissolved based, and TP is particulate based.The number of pre sunny,rainfall, rain intensity andunderlying surfaceare important factors of eventmean concentration(EMC) in the rural runoff.Four underlying surfaces have different levels of first flush effect, and the degree of first flush is influenced by rainfall, rainintensity,the number of pre sunny and underlying surface.(2)The SS, COD, TN and TP pollution loads entering the receiving waterbody were approximately 104.6kg,35.3kg,3.2kg and0.47kg in 2014. The rural rainfall runoff has certain significant impact on the water quality, the pollution concentration in receiving water incrased by 41.7%～155.6%.(3)By using water quantity and quality ofrural rainfall runoff, SWMM model’s hydrological and water quality parameters werecalibrated, then the model based on SWMM model was built. After that, the pollution model wasvalidated, and the results show that the applicability of SWMM model in such small placeis satisfactory by the NS efficiency coefficient which is between 0.36 to 0.75.