Characterization Of COD Components In Maotai-flavor Liquor Wastewater And Optimization Of Treatment Process

China’s liquor brewing process has profound history.While the liquor brewing industry promotes economic development and creates economic value,the production of wastewater has caused harm to the environment.Existing wastewater treatment is in urgent need of optimization due to complicated processes,high operating costs,and effluent COD that can no longer meet the requirements.This thesis characterizes the COD components in each biochemical stage of the existing Maotai-flavor liquor wastewater,analyzes the main organic matter composition,and focuses on the transformation of refractory organic matter between biological treatment.Prepare simulated wastewater containing representative refractory substances,analyze the treatment efficiency of each process and the effectiveness of refractory organics through a single process or a combination of processes,and find an"efficient and economical"treatment to provide theoretical basis and scientific basis for guiding the optimization of the existing liquor wastewater process.The following conclusions are drawn:（1）The COD components of Maotai-flavor liquor wastewater were characterized by chemical analysis,FTIR and GC-MS:raw water COD 9350 mg·L^-1,anaerobic effluent COD 3425 mg·L^-1,aerobic effluent COD 1625 mg·L^-1.FTIR and GC-MS showed that the COD components in the three wastewaters were all benzene-containing organics,long-chain organics,nitrogen-containing organics,phenols and carboxylic acids.The refractory organics in raw water are mainly composed of benzene-containing organics represented by1-methyl-4-cumene,long-chain organics represented by heptanoic acid,octanoic acid and nitrogen-containing organics represented by didodecyl（dimethyl）azanium,bromide,accounting for 27.44%,52.80%and 12.69%of the total organics respectively;The anaerobic effluent refractory organics are mainly composed of benzene-containing organics represented by 4-methylphenol,long-chain organics represented by caprylic acid,nonanoic acid,capric acid and nitrogen-containing organics represented by amino acids,accounting for 43.96%,18.31%and 33.72%of the total organic matter respectively;The refractory organic matter in aerobic effluent is mainly composed of benzene-containing organic matter represented by 4-methylphenol,long-chain organic matter represented by1,1-dimethoxydodecane and nitrogen-containing organic matter represented by 2-methyl-7-aminobenzofuran,accounting for 65.76%,11.15%and 20.22%of the total organic matter,respectively.The characterization results show that the COD components in raw water,anaerobic effluent and aerobic effluent are complex and contain characteristic organic compounds that are refractory to degradation.（2）In order to avoid the interference of the complex components of COD,for the three characteristic organic compounds of 4-methylphenol（representing benzene-containing organics）,n-octanoic acid（representing long-chain organics）and bovine albumin（BSA,representing proteins and nitrogen-containing organics）with high content in the refractory organic matter of the wastewater,a simulated solution was prepared to carry out the degradation experiments of iron carbon and Fenton in a single process.The results show that the Fenton process has strong destructive ability to benzene,C-C,C=O,C-N,N-H and other structures,and can effectively decompose benzene,long-chain and nitrogen-containing organic compounds in wastewater.The iron-carbon process has limited ability to degrade these three types of organics.（3）Taking the existing anaerobic process as the core,the iron-carbon process and the Fenton process were combined to treat the simulated wastewater in（2）,compared with a single process,it is found that the iron-carbon process,as the pretreatment of the anaerobic process,can greatly promote the degradation of long-chain organic matter by anaerobic microorganisms;the Fenton process is placed at the back end of the anaerobic process,which can better remove the refractory organic matter in the anaerobic effluent.（4）The"iron-carbon-anaerobic-Fenton reflux process"was used to carry out a verification experiment on the actual wastewater of Maotai-flavor liquor,and the results showed that:In the 30-day continuous water inflow experiment,the effluent COD reached965 mg·L^-1.Compared with the effluent of a single anaerobic process,the COD removal efficiency increased from 63.37%to 89.68%,an increase of 26.31%.The actual wastewater was treated by a single anaerobic process,and the removal rates of benzene-containing organic matter,long-chain organic matter and nitrogen-containing organic matter in the wastewater were 31.82%,52.75%and 63.81%,respectively;after the optimized combination process,the removal rates of the three types of organic compounds were 64.87%,67.40%and 68.76%,respectively,and the removal rates were increased by30.39%,14.65%and 4.95%,respectively,and the removal effect of benzene-containing organic compounds increased significantly.