Study On Penicillin Production Wastewater Treatment By Anaerobic Activated Sludge

As the first antibiotic discovered by humans,penicillin is widely used in the treatment of bacterial infections due to its high efficiency and low toxicity.Its mechanism of action is to inhibit bacterial cell wall mucin synthase(i.e.,penicillin binding protein),resulting in cell wall defects,which ultimately leads to cell swelling and demise.Penicillin fermentation production wastewater has a high concentration of organic matter(COD is generally5000-30000 mg/L),and also contains up to thousands of mg / L of residual penicillin.It needs to be effectively treated to reduce its potential pollution to the receiving water,especially to reduce residual effects of developing resistance bacteria and gene caused by penicillin emission.On the one hand,the anaerobic activated sludge process does not require oxygen and energy consumption,and can use the organic matter in the wastewater to generate methane to recover energy.On the other hand,its main methanogenic bacteria belong to archaebacteria withsignificantly different cell wall structurefrom other bacteria,making it may withstand high concentrations of penicillin.Therefore,this study first explored the interaction mechanism of penicillin and anaerobic activated sludge through short-term experiments,and then investigated the comprehensive effects of different penicillinconcentrations on the operation of anaerobic sequential batch reactor(AnSBR)through long-term experiments,including organic matter degradation,methane yield,penicillin removal,and microbial community.cThe short-term anaerobic fermentation test of the methanogenic potential test system showed that: low concentration(?10 mg/L)of penicillin G sodium salt has no obvious inhibitory effect on the activity of anaerobic sludge;high concentration(100 mg/L,1000 mg/L)Penicillin G sodium salt has a significant inhibitory effect on the activity of anaerobic sludge,and its methane production is 63.95% and 19.88% of that of normal anaerobic sludge,respectively.The hydrolysis of penicillin G sodium salt conforms to the first-order reaction kinetics.The hydrolysis rate has a positive correlation with the solid phase adsorption points in the water.The higher the concentration of inactivated sludge,the more the adsorption points of the sludge flocs,the more the hydrolysis rate Fast;anaerobic activated sludge can obviously promote the hydrolysis of penicillin G sodium salt.The time to reach 99.9%hydrolysis rate is 24 h,which is significantly faster than 120 h under pure water.The long-term test of AnSBR treatment to simulate the production wastewater of penicillin G sodium salt showed that the concentration of penicillin G sodium salt ?100 mg/L had no significant effect on COD removal and methane production.The removal rate can reach 82%,and the methane conversion rate can reach 71%.The high concentration(1000 mg/L)of penicillin G sodium salt significantly inhibited the activity of anaerobic sludge,causing a large amount of sludge loss.Methanobacteria and Methanobacterium are the basic genus of anaerobic activated sludge for the treatment of penicillin G sodium salt,and their proportion in the flora is not significantly related to the concentration of penicillin G sodium salt;Methanobacterium,Archaebacterium,Methanosarcina When the penicillin G sodium salt concentration is ?100 mg/L,it is the main methanogenic genus;when the penicillin G sodium salt concentration is 1000 mg/L,the proportion of archaebacteria and Kristenella significantly decreases.This study demonstrated that anaerobic sludge could withstand 100 mg/L penicillin,enhanced its hydrolysis and kept good methane production potential.It also provided technical supports for the practical application of AnSBR process for penicillin production wastewater treatment.