Preliminary Experimental Study On Interception And Purification Of Urban Non-Point Source Pollution By Ecological Filter

In the process of collection and migration,urban non-point source pollution is not effectively intercepted and purified,and discharged to the receiving water body directly,resulting in frequent change of water quality in urban environment and even degradation of water ecosystem.The ecological filter has the advantages of less construction areas demand,low construction cost and good for landscaping.In recent years,it has been widely used in the field of rural domestic sewage treatment.However,as a newly developed ecological treatment process,ecological filter still has a large excavation space in terms of process performance.In engineering application,it is faced with problems such as lack of design parameters and unpredictable effect.In this paper,nine groups of ecological filter systems were set up by three plants?corymbos,iris flavescens and Canna edulis?and three fillers?shell,vermiculite and activated carbon?to compare the removal efficiency for typical pollutants in the initial rainwater of the road.The first-order dynamic model was simulated according to these data.The main conclusions are as follows:?1?It was found that with the extension of treatment time,the removal efficiency of pollutants in each group of ecological filter showed a gradual increase trend,but the difference was uncertain on the time scale;the removal load of pollutants in 9 groups of different treatment systems fluctuated greatly between each week,and appeared in the third week to the fifth week The peak value,one week,contributed 35.43% ? 46.57%?total phosphorus?,10.06% ? 25.86%?ammonia nitrogen?and 17.82% ? 33.36%?COD?of the total load of each pollutant during the whole test period.?2?The results of orthogonal optimization show that the purification effect of the ecological filter constructed by shell powder and umbrellas is relatively good;the concentrations of total phosphorus,ammonia nitrogen and COD in the sewage are 2 mg / L,10 mg / L and 200 respectively At mg / L,the removal rates of total phosphorus,ammonia nitrogen and cod were 84.94%,86.12% and 89.26% respectively;the concentration of sewage and the type of filler had a greater impact on the removal of total phosphorus,ammonia nitrogen and COD,while the plant species had a smaller impact.?3?In the experimental period,the best combination of total phosphorus removal amount is A1B3C3,and the total phosphorus removal amount reaches 9.28 mg.d^-1.m² in the third week,that is,the combination of total phosphorus 4mg/L,ammonia nitrogen 20mg/L,COD 400 mg / L,shell powder and Canna;the best combination of ammonia nitrogen removal amount is that the ammonia nitrogen removal load of A1B3C3 reaches 49.14 mg.d^-1.m²,that is,the total phosphorus 4mg / L,ammonia nitrogen 20 mg / L,cod400 mg / L shell powder and Canna Canna combination.The best combination of COD removal amount is A1B3C3,the highest COD removal load is 1025.21 mg.d^-1.m²,that is,total phosphorus 4mg / L,ammonia nitrogen 20 mg / L,COD 400 mg / L,shell powder and Canna.?4?Through the kinetic simulation study,it is found that the first-order reaction kinetic model can also better describe the removal kinetics of total phosphorus,ammonia nitrogen and COD in the ecological filter system,and the simulation of the removal kinetics of ammonia nitrogen and cod has better applicability.The kinetic parameters of total phosphorus removal,ammonia nitrogen and cod were 0.0235-0.0478 D-1,0.0222-0.0548 D-1 and 0.022-0.0607 D-1,respectively.The calculated kinetic constants vary with plant species,filler types and pollutant concentration levels.