| Non-point source pollution has become an important factor affecting the quality of the surface water.Early urban runoff has a great influence on river water quality,so governance approaches suitable for the situation of our country must be found.The artificial rapid filtration system（CRI）plays an important role in the treatment of domestic sewage,but there has been less research on the treatment of early runoff.This paper is based on the national "twelfth five-year" Yixing water subject of "urban water pollution control and water environment function upgrade technology research".According to the subject around "urban drainage overflow pollution control technology research",this paper put forward an artificial rapid infiltration treatment system using new packing,and the laboratory simulation experiment collecting the early rain runoff was carried out,verifying the feasibility and stability of artificial rapid infiltration treatment system dealing with early runoff pollution,and optimizing its parameters,so as to explore the pollutants removal performance in the system.The main contents of this paper are as follows:（1）On the investigation of Yixing different functional areas of surface runoff water quality,research shows that: the average concentration of main pollutants in different functional zones in the early rain runoff in Yixing was more than V class water: average concentration of COD,TN,TP and NH+4-N and NO-3-N were 280.94,15.35,8.26,4.81,1.06 mg/L,rainfall runoff pollution is serious.（2）Using two artificial rapid filtration systems with traditional and special packing to handle the initial rain runoff,the laboratory adopts organic glass columns for the simulated test.The results showed that COD and NH+4-N reached steady state in 17 days and 23 days respectively,and the average water concentration of COD was 45 and 43 mg/L respectively,and the removal rate was 83.63 and 82.64% respectively.The average water concentration of NH+4-N was 2.17 and 1.92 mg/L respectively,the average removal rate was 73.97 and 76.68% respectively,verifying the feasibility of the CRI system in dealing with initial rainfall runoff.（3）Optimization of the operation parameters of the manual rapid infiltration system,through to the different wet dry ratio,hydraulic load and hydraulic load cycle on the experimental study of water effects of CRI system,the wet-dry ratio was 1: 3,and the hydraulic load was 2 m /d and the hydraulic load period is 12 h,the system has the best effect on the whole runoff.（4）Exploring the variation law of pollutant index in artificial rapid infiltration system,the results show that the removal rule of the two systems is basically the same,the removal of COD mainly occurred in 90 cm of the upper packing section;The removal of NH+4-N mainly occurred in 60 cm of the upper packing section;The removal of TN mainly occurred in 120 to 150 cm of the lower packing section;The removal of TP mainly occurred in 60 to 120 cm of the middle packing section.The addition of the special packing system of steel slag and chaff is better.（5）Artificial rapid infiltration system experienced a long period of drying,the removal ability recovery towards the initial rain runoff after restart was studied,the results show that adding special packing system and traditional packing system can quickly restore to the processing capacity of COD and NH+4-N,but in the treatment of TN and TP,add special packing system compared with traditional packing have fast and good resilience,the average removal rate increased by 15.25% and 17.44% respectively.The addition of special filler can also improve the stability of system operation,and improve the operation of the system in the actual project. |
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