Removal Of Estrogens In Cow Dung Using Estrogen-degrading Strain E2S And Fenton Oxidation Technique

Environmental estrogen pollution leads to a series of ecological safety and public health problems,which has aroused wide attention from all over the world.At present,livestock manure produced by large-scale cultivation has became an important source of environmental estrogen pollution.In order to realize innocent treatment and resource utilization of livestock manure,how is simple,efficient and rapid to remove the estrogen pollution of livestock manure?The study has become one of the hot spot of research at home and abroad.A 17?-E2 degrading bacteria strain E2S was isolated from activated sludge of a sewage treatment plant.The growth and degrading features of strain E2S was studied.The effects of several kinds of antibiotics on the strain E2S degradation performance were explored.The optimum conditions of Fenton reagent to remove the estrogen in livestock manure were optimized.The main results are as follows:(1)Strain E2S was identified as Sphingomonas sp.based on physiological characteristics and 16S rRNA Sequence homology analysis.It could degrade 63.3%of E2 in 7 days under laboratory culture conditions.Strain E2S was aerobic,and its optimum growth conditions were 30?,pH 7.0 and no added salt.It was observed that strain E2S could resist erythromycin,streptomycin,tetracycline and spectinomycin,and the low concentration of chloramphenicol and ampicillin,but it was sensitive to gentamicin and kanamycin.The optimum conditions for E2 biodegradation by the obtained strain were 30?,pH 7.0,50 mg·L-1 E2,5%of inoculation amount,no added NaCl,and 10 mL of liquid medium volume in 100 mL flask.(2)The impact of low concentration of antibiotics on degradation performance of strains E2S in pure culture system and cow dung was low.In pure culture system of penicillin(0.1 ug·mL-1),erythromycin(0.8 ug·mL-1),oxytetracycline(3.2 ug·mL-1)and tetracycline(12.8 ug·mL-1),the degradation rate of treatment group after 7 days was respectively 59.9%,61.0%,59.8%,59.9%,which had fallen by 3.4%,2.3%,3.5%,3.4%.In the cow dung,the degradation rate of treatment group after 7 days was respectively 60.6%.61.0%?62.3%?64.7%,which had fallen by 5.8%?5.4%?4.1%?1.7%.The impact of high concentration of antibiotics on degradation performance of strains E2S in pure culture system and cow dung was great.In pure culture system of penicillin(0.1 ug·mL-1),erythromycin(0.8 ug·mL-1),oxytetracycline(3.2 ug·mL-1)and tetracycline(12.8 ug-mL"1),the degradation rate of treatment group after 7 days was respectively 13.9%,17.0%,12.2%,14.8%,which had fallen by 49.4%?46.3%?51.1%?48.5%.In the cow dung,the degradation rate of treatment group after 7 days was respectively 13.2%,14.7%,12.6%,15.8%,which had fallen by 53.2%?51.7%?53.8%?50.6%.(3)Fenton oxidation technology was able to remove five kinds of estrogens(E3,BPA,DES,E2,EE2)in laboratory simulation pollution cow dung effectively.The experimental optimum reaction conditions were the 10%citric acid dose of 50 ?L,the solid to liquid ratio of 2:1,pH of 3.0,30%H2O2 concentration of 11%,iron adding ratio of 1/8(28%FeSO4 dose of 2.63 mL)and the reaction time of 24 h.Under the experimental conditions,the removal rates of five kinds of estrogens were 84.9%,99.5%,99.1%,97.8%and 84.5%.