Study On The Efficacy Of Anaerobic Co-metabolism To Remove Veterinary Antibiotics From Swine Wastewater

With the intensive and large-scale development of the livestock and poultry industry,veterinary antibiotics were widely used to prevent and treat animal diseases.The heavy use of antibiotics has become one of the important sources of antibiotic pollutions in the natural environment.In order to reveal the effect of anaerobic co-metabolism on the removal efficiency of antibiotics in swine wastewater,antibiotics,sulfamethoxine?SMM?and oxytetracycline?OTC?,with high detection rate and high residue in swine wastewater were studied.Anaerobic digestion was carried out by adding a co-metabolism substrate to the swine wastewater.The co-metabolism substrate?corn stalk,cellulose,cellobiose and glucose?consisted of VS_{inoculated sludge}:VS_{co-metabolism substrate}=1:0.2,1:0.5,1:1,1:2?based on organic matter content?,and no co-metabolism matrix was added to control group?CK?.Finally,the effects of the stability of anaerobic reaction system,gas production performance,the removal rate of antibiotics?SMM and OTC?and the succession of microbial communities in antimicrobial degradation?SMM and OTC?were explored under different types of co-metabolism matrix to understand the removal mechanism of anaerobic co-metabolic degradation of veterinary antibiotics.Research shows:?1?The anaerobic digestion system will not be retarded by the addition of co-metabolism matrix.The accumulation of methane?CH₄?components,cumulative biogas production and cumulative methane production could be improved by accelerating the rate of substrate hydrolysis and methane production in the anaerobic digestion system.Meanwhile,the cumulative of biogas and methane production increased with the addition of co-metabolic matrix.Among them,the experimental group of VS_{inoculated sludge}:VS_{corn stover}=1:2 had the highest cumulative biogas and methane production,reaching about 964.43 m L/g VS and 575.56 m L/g VS,respectively.?2?According to the analysis of first-order kinetic equations,it was found that the addition of co-metabolism matrix not only shortened the degradation cycle of SMM and OTC,but also improved the degrading capability of SMM and OTC.The proportion of VS_{inoculated sludge}:VS_{corn stover}=1:2 had the strongest removal capacity on SMM?71.04%?and OTC?99.37%?in wastewater,respectively.Co-metabolism process occurred in all the experimental groups added with co-metabolism matrix.According to the adsorption degradation equilibrium of antibiotics,it was found that anaerobic biodegradation was the major removal mechanisms of SMM and OTC in wastewater.?3?The relative abundance of microorganisms with degradable functionalities increased with the addition of co-metabolic substrates in the digestive system of each experimental group,such as:Bacteroidetes,Bacilli,Pseudomonas,Synergistestes,Bacteroidia,Aestuariicella,Actinobacteria and norank?f?Bacteroidetes?vadin HA17.The exist of those microorganisms could promote the removal of antibiotics?SMM and OTC?from pig farm wastewater.