Study On Deep Treatment Of Sewerage With The Combination Process Of Biological Contact Oxidaation And Constructed Wetlands

Along with the development of economic, the growth of population and the accelerating urbanization process, as well as the continuing expansion of the scale in crease higher costs for sewage treatment. Accroding to these situation, to establish decentralized sewage treatment in the district as soon as possible become an important tool to solve the problem of sewage disposal and conducive to the reuse of treated water, also it do good to the efficiency of social, economic and environment.This paper mainly discussed the treatment of district sewerage with the combination process of biological contact oxidation and constructed wetlands. Research in different operation mode of the different gas water ratio, and different temperature, the aeration time different under the condition of the treatment effect of combined technique, discusses this combination technology working conditions, function mechanism and influencing factors.Specific conclusions are as follows:(1)With the condition of water pollution loads in low(COD for 60～80mg/L,NH4+ N for 15.25～24.68mg/L, TN for 26.69～37.80 mg/L, TP for 1.89～2.36mg/L,SS for 100～150mg/L combination process run continuously, biological contact oxidation pool for 2.10m3/m2·d, wetland system for hydraulic loading 1.05 m3/m2·d, effluent is in accordance with the urban sewage treatment plants standards for pollutants discharge (GB/T18921-2002) and the level A standard urban wastewater recycling - landscape environment of renewable water quality standard of water (GB/T18921-2002) requirements, normal temperature conditions this system gas water 3:1 in experimental conditions, the optimal conditions Low temperature conditions than gas water for optimal conditions then.was 6:1.(2) Intermittent operation, in water (COD for 69.66-93.65 mg/L,NH4+ -N 18.29～26.38 mg/L, TN for 25.62～35.68 mg/L, TP for 1.98～2.36 mg/L, biological contact oxidation pool water power load for 2.10 m3/m2·d, wetland system for hydraulic loading 1.05 m3/m2·d combination technology in water respectively 12h, drainage 12h and fill the 18h 6h, drainage condition of COD, NH4+ -N, TN, TP have good processing effects and the effluent can achieve the concentration of urbansewage treatment plants standards for pollutants discharge (GB8918-2002) andthe level A standard urban wastewater recycling-landscape environment of renewable water quality standard of water (GB/T18921-2002) standards, comprehensive consideration of the combined craft removal efficiency, energy costs can be determined when the intermittent operation combination process for the optimal conditions 18h water drainage.(3) Continuous operation, normal temperature conditions and low temperature conditions, artificial wetland internal NH4+-N vertical direction change clearly, from the current direction upwards, especially in decreasing 20 cm most obvious deep changes to the surface. Lower concentrations of regional denitration nitrogen (low and the concentrations of nitrogen, ammonia nitrogen are relatively high, total nitrogen in the lower is higher, the upper area is lower; Intermittent operation, artificial wetland internal nitrogen and phosphorus in vertical direction along the flow direction after first increases, reducing is mainly due to water plants decay of nitrogen and phosphorus release.(4)The gas water ratio COD, TP, SS remove effects that affect the small, but improve gas water than NH4+ -N and TN removal has obvious stimulative effect. Temperature on COD, TP, SS removal influence is very small, but for NH4+-N and TN removal has very big effect. Contact oxidation process on COD, NH4+-N removal contribution is bigger, TN, TP, SS removal rely mainly on the artificial wetland system.(5)The spatial distribution of wetland internal nitrogen and phosphorus significant difference, horizontal TP, PO43- P, NH4+ -N, TN concentrations along the flow direction gradually decrease, NO3 -N and NO2-N rose at first, then decreased, vertical orientation NH4+ -N, TN in wetland matrix 20cm and deep inside most obvious 40cm changes, the wetland front-end superstratum is NH4+ -N the main area of wetland removal, the lower after the main site is TN remove; PO43 -P, TP respectively in wetland matrix 40cm and 20cm and deep inside, the most obvious changes the absorption and matrix with plants the adsorption effect of relevant.