Research On The Effect Of Ecological Floating Bed Based On Different Substrates In The Treatment Of Tail Water From Sewage Plants

The tail water of the sewage plant is the discharged water after the treatment of the sewage plant.The effluent quality of most sewage plants is required to be Grade A standard.Direct discharge still has the risk of causing eutrophication of the receiving water body,so further treatment of the tail water is necessary of.Ecological floating bed technology is widely used in water treatment because of its low price,ecological and environmental protection and other advantages.In order to make the tail water have better treatment effect in the floating bed,this paper uses different substrates to construct the ecological floating bed to treat the tail water,explores the removal characteristics of zeolite,ceramsite and sponge iron substrate for pollutants,and examines the different substrate construction The long-term treatment effect of the ecological floating bed on the tail water,and a preliminary analysis of the nitrogen removal mechanism in the matrix floating bed,provides an experimental basis for the purification of the tail water of the sewage plant by the floating bed,and studies the best combination of substrate and ecological floating bed.The main conclusions are as follows:(1)In the experiment of nitrogen and phosphorus removal characteristics of zeolite,ceramsite and sponge iron matrix,it was found that under the experimental conditions,the removal rates of phosphorus by zeolite,ceramsite and sponge iron were 24%,67%and 77%,respectively;The removal rates of NH4+-N by ceramsite and zeolite are 31%and 71%,respectively,but sponge iron has little effect on removing ammonia nitrogen;the removal rates of NO3--N by zeolite,ceramsite and sponge iron are 5.17%,3.11%and 87%.(2)The operation effect of the ecological floating bed constructed with different substrates shows that the combination 4(water onion+ceramsite:zeolite:sponge iron=1:1:1(mixed))has the best removal effect,and the floating bed has a better effect on TN after 6 days,The average removal rates of NH4+-N,NO3--N and P are 93.0%,94.6%,93.7%and 95.4%,respectively.The concentration of nitrogen and phosphorus effluent can reach the surface water quality standard of Class Ⅳ,and the average removal rate of UV254 is 43.8%,the dissolved organic matter(DOM)in water mainly includes protein-like and humus-like components.(3)The analysis of nitrogen removal in the floating period of the experimental group found that the removal process of NO3--N and NH4+-N by the combined 4 ecological floating bed conformed to the first-order kinetic model,and the degradation rate of NO3--N was faster.In summer and winter,the total floating nitrogen removal rate of 4 floating beds is maintained above 85%,and it is more reliable to remove pollutants by adsorption of the substrate.There is a significant positive correlation between the value of UV254 and the redox potential in the floating bed of combination 4,and there is a significant negative correlation between the concentration of NH4+-N and the water temperature.