Study On The Stability Of Sewage Biochemical Treatment System Under The Impact Of Capsaicin

Capsaicin has strong antibacterial activity due to its specific chemical structure,and studies have shown that capsaicin can inhibit the activity of microbial dehydrogenase.At present,there are few studies on capsaicin in the field of sewage treatment,and the few studies mainly are the discussion on the treatment process of wastewater containing capsaicin,and mainly focus on the oil and salt in the wastewater,only treating capsaicin as a conventional organic pollutant.In view of the research blank of capsaicin in the field of wastewater treatment,this paper discusses the impact of capsaicin on the wastewater biochemical treatment system,selected three bacterium with functions of degradating capsaicin,identified the microbial intermediate metabolites of capsaicin,preliminarily discusses the microbial metabolic pathway of capsaicin,finally has carried on the research of wastewater biochemical treatment system under bioenhanced repair of capsaicin shocks.Through the experiment on the effect of capsaicin on sewage biochemical treatment system,the following conclusions are drawn:capsaicin can promote the growth of Colibacillus,but has different degrees of inhibition on the growth of Lactobacillus,Bacillus Subtilisin,Staphylococcus aureus;Capsaicin can reduce the concentration and sedimentation of activated sludge in sewage biochemical treatment system.Capsaicin will reduce the removal effect of the biochemical system on COD_Cr,ammonia nitrogen and total nitrogen,respectively decreased by 13.64%,14.97%and13.4%.Capsaicin basically does not affect the removal of total phosphorus by the system.Based on the analysis of MiSeq high-throughput sequencing results,it was found that capsaicin would reduce the Alpha diversity of the microbial community in the sewage biochemical treatment system,resulting in significant changes in the composition of the microbial community in the system at the phylum,class and genus levels.Three functional bacteria Cap B,Cap E and Cap Z with capsaicin degradation effect were selected from different sludge sample sources,and their degradation rates were28.8%,21.3%and 40.5%,respectively.They were identified by molecular biology as belonging to Serratia marcescens subsp.marcescens?Bacillus tequilensis?Lactobacillus plantarum subsp.plantarum.Five unreported metabolites were identified by HPLC-MS analysis of intermediate metabolites of capsaicin,and it was speculated that modification of side chain of capsaicin and hydrolysis of amide bond were the key steps for the degradation of capsaicin by the bacterial strain.Through orthogonal test,the optimal ratio of capsaicin-degrading functional bacteria was Cap B:Cap E:Cap Z=1:2:4.Meanwhile,a compound bacterial agent Cap-FJ was constructed to repair the impact of capsaicin on sewage biochemical system.Cap-FJ was added to the sewage biochemical treatment system,and it was found that capsaicin was effectively treated with compound bacteria.During the operation of the system,the average concentration of capsaicin in the effluent was 29.26mg/L,and the average removal rate was 70.73%.Bioremediation restored the adverse effect of capsaicin on the removal of COD_Cr,ammonia nitrogen and total nitrogen in the sewage biochemical treatment system,and enhanced the system's ability to remove COD_Cr,ammonia nitrogen and total nitrogen,but had no significant promoting effect on the removal of total phosphorus.The adverse effects of capsaicin on microbial community in sewage biochemical treatment system were repaired by bioremediation,and the composition of microbial community in phylum,class and genus changed obviously.