Research On Performance Of Hydrolysis Acidification-SBR-Fenton Combined Process In Treating Filtrate Of Thermal Hydrolysis Of Sludge

The waste water treatment plant in southern China introduced sludge thermal hydrolysis technology to reduce the sludge.However,the high concentration organic filtrate generated in the process of thermal hydrolysis directly returned to the bio-chemical system,resulting in the risk of effluent COD exceeding the standard under high discharge standard.Based on this,this project takes the filtrate as the treatment object,adopts the hydrolysis acidification-SBR-Fenton combined process technology,explores the optimal process parameters and operation efficiency of the combined process,deeply analyzes the structural characteristics and functional differences of microbial community,and clarifies the micro mechanism of action,so as to provide a possible solution for this filtrate.The operation results of hydrolysis acidification process showed that with the increase of influent organic load rate（stage I～V）,the removal rate of COD decreased from 55.2%to 7.6%.Too high organic load rate significantly inhibited the activity of anaerobic microorganisms,resulting in the decline of hydrolysis acidification effect.The process optimization results showed that the optimal influent organic load rate was 4.29 kg COD/（m³?d）,the COD removal rate was 8.2%,the acidification degree was 28.2%,and the BOD₅/COD value was increased from 0.36 to 0.51.The analysis of microbial community structure showed that organic load rate significantly changed the characteristics of community structure.Firmicutes and Bacteroidetes were the main dominant bacteria,while methanogens was dominant in archaea.PICRUSt pre-diction showed that methane metabolism,amino acid metabolism and carbohydrate metabolism were significantly related to organic matter degradation.The operation characteristics of SBR process for treating hydrolytic acidifica-tion effluent were explored.The results showed that when the influent COD concen-tration increased from 2000 mg/L to 10000 mg/L,the COD removal rate decreased from 63.0%to 48.2%.At this time,the removal rates of COD,ammonia nitrogen and TN were 48.2%,15.9%and 16.7%respectively.The results of high-throughput se-quencing showed that the microbial community changed significantly after inocula-tion to adapt to the changes of the external environment,and the abundance of pro-teobacteria,actinobacteria and firmicutes increased significantly.Functional gene prediction showed that the abundance of propionate metabolism,butyrate metabo-lism,fatty acid metabolism and valine,leucine and isoleucine degradation increased significantly.The main influencing factors of Fenton oxidation process were explored.The results showed that the primary and secondary relationship was:the dosage of H₂O₂>the dosage ratio of H₂O₂to Fe²⁺>the initial p H>the reaction time.The optimum operation parameters were as follows:the dosage of H₂O₂ was 8.6 g/L,the molar ratio of H₂O₂ to Fe²⁺was 3:1,the initial p H was 2.00 and the reaction time was20 min.At this time,the effluent COD reached 984 mg/L,and the removal rate reached 77.1%.In conclusion,the combined process of hydrolysis acidification-SBR-Fenton had good treatment efficiency for the filtrate of thermal hydrolysis of sludge,which can meet the set target requirements and significantly reduce the risk of the effluent COD exceeding the standard of high discharge standard.