Optimization Of Processing Parameters Of Hormone Pollutants In Constructed Wetland Treated Wastewater

China is the world's largest livestock and poultry breeding countries,the annual emissions of livestock and poultry waste close to 4 billion t.In addition to conventional pollutants,hormones are also livestock and poultry breeding important pollutants.In 2007 China's livestock and poultry breeding caused by steroid estrogen is 10.6t,2008 emissions more than 5 times.In this paper,three types of constructed wetlands were designed and constructed to solve the problem of conventional pollutant removal and excessive concentration of hormone pollutants in livestock and poultry wastewater.Under the condition of ensuring the removal effect of conventional pollutants,the wetland type,HRT and wetland plants infect the removal of four glucocorticoids in constructed wetlands.Through the static shake flask experiments found that by considering the price and the removal rate,screening out the best subtrates for this experiment.During the experiment,the removal efficiency of COD,NH4+-N and TP in vertical wetland was the best,and the removal rates were 65%,95%and 90%,respectively.When the HRT was 2 days,the average removal efficiency of the conventional pollutants was the best.In the study of constructed wetlands on the role of four kinds of glucocorticoids found in the effect.When the hydraulic retention time is less than 1 day,the presence or absence of plant in wetland has little effect on the removal of hormones.With the extension of HRT,the wetland of planted plants was significantly better than that of plant-free hormones.The removal efficiency of four kinds of hormones was the best,and with the extension of HRT,the removal rate of each system was improved.When HRT was 2 days,the removal effect was the best.In the harvested wetland plants,the adsorption capacity of the four kinds of hormones was different,and the average adsorption capacity of the lythrum salicaria was the highest,and the content of dexamethasone was the highest in plants.In the detection of samples,all stages of the detection of metabolites.After planting plants,the amount of metabolites in the wetland effluent increased,and the concentration of most metabolites increased.Prolonging the hydraulic retention time,the concentration of metabolites in the surface wetland,and the increase of the species,the horizontal flow and the vertical flow wetland,and the less kinds of metabolites.In the harvested wetland plants,the concentration of metabolites is between several ng/g and several hundred ng/g.According to the tail water of the original pig farm in Changping District of Beijing,the designed influent and effluent concentration of TP were 8 to 0.4 mg/L,COD were 300 to 40 mg/L and NH4+-N were 20 to 2 mg/L.The treatment scale were 300 m3/d.