Study On The Efficacy Of EGSB In Treating Orthochlorophenol Wastewater And Analysis Of Microbial Community Structure

2-chlorophenol is a type of persistent organic pollutants which are widely found in the environment.Its strong biological toxicity and hard-to-degrade properties have caused damage to water ecological and biological health.Is a type of environmental pollutant that needs strict control and emission.The experiment use EGSB anaerobic bioreactor as a research platform to study the anaerobic treatment efficiency under the condition of low concentration to high concentration of 2-chlorophenol water distribution.At the same time,optimization experiment of running parameters is carried out,and the morphology characteristics of micro-organisms in granular sludge,extracellular EPS microbial and community structure and functional genes have been studied.The reactor has good 2-chlorophenol treatment efficiency from the lowconcentration(3mg/L)to high-concentration(300mg/L)after a period of domestication.The processing capacity of 2-chlorophenol rise 0.06 mg/(g VSS·d)up to 2.96 mg/(g VSS·d).When the temperature is 35°C,the p H environment is about 7 and the hydraulic retention time HRT is 24 h,the reactor has good and stable treatment effect on the 2-chlorophenol water distribution below 100 mg/L,and the COD and 2-chlorophenol removal rates are stable at over 95%.In the process of acclimation from low to high concentrations,the granular sludge structure became looser,the average particle size increased,and the VSS/TSS value decreased.At the same time,the EPS in granular sludge increases with the influent concentration,and the PS content of polysaccharide also increases significantly and PS/PN remaines at a high level.Under the condition of low concentration of influent water(10mg/L),after short-term acclimation of granular sludge,the orthochlorophenol can be effectively removed under the operating parameters of PH6-8 and HRT for 16 hours.Under the condition of moderate concentration(60mg/L)orthochlorophenol influent,the temperature of 24°C,HRT for 24 h can ensure the good removal effect of the reaction system on o-chlorophenol,and the water should be controlled at neutral(p H=7)And partial acid(p H = 6)environment.At a temperature of 35°C and a p H of 7,the retention time of HRT is only 9 h,and o-chlorophenol can be effectively removed.In the case of high-concentration(100 mg/L)o-chlorophenol influent,the reactor should be strictly ensured to operate at 35°C and neutral p H,and the reactors that performed well after acclimatization can shorten the HRT to 16 h.Methanosaeta,Methanolinea,Methanobacterium,Mesotoga and Dehalobacter are genus species with high abundance in granular sludge.COG0654,COG1071 and COG0022 functional genes of the three important proteins and AA6 enzyme functional genes were detected in the sludge.These genes are closely related to the degradation and metabolism of o-chlorophenol and other aromatic compounds.At the same time,Methanosaeta,Methanolinea and Methanobacterium are closely related to the degradation of the benzene ring of aromatic compounds,while Mesotoga and Dehalobacter are important functional genuses of anaerobic degradation of 2-chlorophenol.