| With the rapid development of China's industrial level of modernization,the development of agriculture,the rapid growth of urban population,China's urban sewage plant load,the number of urban sewage pollution sources increased year by year.As the city tail water discharge standards become increasingly stringent,urban sewage plant tail water re-processing is imperative.More importantly,the depth of tailwater treatment for the city to solve the problem of water shortage is also important,is conducive to the city's revenue and expenditure and environmental protection.Domestic and foreign studies have shown that aeration biofilter in the sewage denitrification has this greater advantage of artificial wetland sewage for the sewage and phosphorus has a better removal effect.In this paper,the main influencing factors of wastewater treated by aeration biofilter and constructed wetland were tested respectively,and a combination of aerated biological filter and artificial wetland was formed,and the effect of water treatment in combination pilot process was evaluated.The effects of filter media,filtration rate,gas-water ratio,filter layer thickness and backwashing on the water treatment effect of aeration biofilter were studied for aeration biofilter.The results show that the average COD of the built-in ceramsite is37.1mg / L,which is lower than that of the other two filters when the influent concentration is stable at the effluent level A.When the filtration rate is 0.6m / h,the effluent COD concentration is 37.3mg / L,the filter thickness increases in 0.6m,the removal rate of COD and BOD in sewage is higher,the removal rate of BOD is70.44%,The removal rate of COD reached 51.3%.When the ratio of air to water was5: 1,the COD concentration of effluent was the lowest,only 2.75 mg / L.For the constructed wetland,the effect of the constructed wetland filler on the wastewater treatment was studied,and the grade ratio of the constructed wetland filler was established.The effect of the pilot scheme on the tail water was studied.The The results show that the removal rate of TP is higher than that of bioceramics and volcanic rocks under the same hydraulic conditions,and about 70% is about 25 hours.The removal rate of TP and gravel packing is relatively Low only 43.5% and 38.0%respectively.For the mixing ratio of biotite and volcanic fillers,the removal rate of ammonia nitrogen was determined for the combination of the mass ratio of bioceramics and volcanic rocks when the contact treatment time was 50 hours: MIX1:1: 64.2%,MIX1: 2: 67.5,MIX1: 3: 68.3%,MIX2: 1: 81.7%,MIX3: 1: 76.3%.The aerosol filter is a built-in ceramic filter,the filter thickness is 1.8m,thedesign filtration rate is 0.6m / h,the ratio of gas to water is calculated by the combination of the operation conditions selected in the single test.For the 5: 1,artificial wetland selected bio-ceramsite and volcanic rock mass of 2: 1 mixed filler as artificial wetland matrix packing.When the influent water quality is the tail water of the first-class A standard of the WWTP,the treatment of the biological aerated filter+ artificial wetland process shows that the ammonia nitrogen and total nitrogen concentration of the effluent are obviously reduced compared with the influent,The average concentration of ammonia nitrogen decreased from 6.9mg / L to 1.36 mg / L,TN decreased from the average concentration of 14.64 mg / L to 6.66 mg / L.Effluent TP concentration than the influent has a certain reduction in the average concentration of water TP from 0.325 mg / L down to 0.2255 mg / L.The water quality of the water quality standards up to the national surface water ? class water quality standards. |
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