Study On Virus Reduction Mechanism Of Anaerobic Membrane Bioreactor For Swine Wastewater Treatment

With the rapid development of pig breeding industry in China,the pollution-free treatment of swine wastewater has become an urgent problem.As swine wastewater contains a large number of pathogens and toxic and harmful substances,its direct discharge will cause serious pollution to soil and atmosphere,and even directly threaten the living environment of human beings.However,the existing sewage treatment technology cannot meet the requirements of pollution-free treatment of swine wastewater,and the most critical thing is that it cannot effectively avoid the spread of pathogens in the ecological environment,which increases the risk of disease spread and outbreak.Therefore,it is extremely necessary to develop a process that can effectively reduce pathogens.Anaerobic membrane bioreactor（An MBR）,as a novel anaerobic treatment technology,not only achieves wastewater efficient treatment,but also shows its unique advantages in virus removal.However,most studies focus on virus removal in municipal wastewater and lack of studies on virus removal in high-concentration organic wastewater.To fill this gap,Hepatitis E virus（HEV）,Porcine kobuvirus（PKo V）,Porcine epidemic diaeehea virus,hepatitis E virus（HEV）,Porcine Epidemic Diaeehea virus,PEDV)and Transmissible gastroenteritis of pig’s virus（TGEV）were used for quantitative detection by real-time fluorescence quantitative nucleic acid amplification detection system.The removal mechanism of virus from swine wastewater by An MBR was studied systematically.The main conclusions are as follows:（1）It has been proved that swine wastewater achieves high methane yield and high virus removal efficiency in An MBR.Methane yield and chemical oxygen demand（COD）removal efficiency reached 0.26±0.06 L-CH₄/COD_rem and 95.8±0.05%,respectively.At the same time,the removal of HEV,PKo V,PEDV and TGEV was achieved effectively in the reactor,and the maximum removal values of HEV,PKo V,PEDV and TGEV were1.82,3.64,2.67 and 1.84 log.（2）The adsorption capacity of activated sludge to virus and the distribution of virus in sludge mixture were analyzed.The four viruses accumulated in the sludge mixture and were mainly concentrated in solid sludge（more than 90%）.The adsorption capacity of sludge was related to the type of virus.The adsorption capacity of sludge particles for PKo V was the strongest,while the adsorption capacity for TGEV was the weakest.logarithm reduction value（LRV）is positively correlated with adsorption capacity.In addition,the adsorption capacity of solid sludge is related to mixed liquor suspended solids（MLSS）and sludge particle size,but not transmembrane pressure（TMP）.（3）Through the membrane filtration experiment and the virus interception experiment of contaminated membrane module,it was confirmed that the cake layer resistance,the organic membrane pore resistance,inorganic membrane pore resistance and the intrinsic resistance affected the virus removal ability.Among them,virus interception was mainly attributed to membrane pore resistance,followed by the intrinsic resistance.（4）The mechanism study on the effect of hydraulic retention time（HRT）on the removal performance of four viruses was analyzed.HRT has affected the sludge mixture of the particle size distribution,particle size of the median at an HRT was 4 d,the largest was 128.1m,and the sludge of solid phase adsorption viruses most,whereas HRT was2 d minimum,d_m=26.7m,and least sludge solid phase adsorption of the virus.Further study showed that the particle size of sludge was related to the content of polysaccharide,and the increase of polysaccharide content promoted the adsorption of virus in sludge.