Sludge Process Reduction During Wastewater Treatment Based On The Side Anerabic Hydrolysis And Acidification Treatment

A huge amount of sludge is produced in conventional wastewater treatment process,and itsdisposalis costly.Therefore,it is necessary to reduce the sludge yield during wastewater treatment.The side anaerobic hydrolysis and acidification treatment based on the oxic-settling-anaerobic(OSA)process is a very promising technology with the advantages of high sludge reduction efficiency,no chmeicals dosage,simple operation,enhancing nutrient removal and sludge settleability,and facilitated implementation in new plantsorupdating ofold palnts.In this study,modification of sludge process reduction based on the side anaerobic hydrolysis and acidification treatment during wastewater treatment insequencing batch reactors(SBR-SHAR)was investigated.The sludge reduction mechanism was investigated by analyzing and quantifying the reduction efficiency underdifferent reductionpath ways.In addition,the effect of the bypass hydrolysisand acidification on wastewater treatment,community structureand functional bacteria activities was studied.The sludge reductioncharacteristicsof the SBR-SHAR process under different aeration rates were also examined.Conclusions were obtainded as follows:(1)In the SBR-SHAR process,sludge retention time(SRT)was the main contributor to sludge reduction,and metabolic uncoupling and hydrolysis acidification contributed little to the sludge reduction.The sludge reduction in the OSA process with SHAR was 42%,with the contribution by long SRT of 33%,energy uncoupling of 7.7%,hydrolysis/acidification of 1.1%,and others of 0.2%.(2)The sludge reduction incorporated had no obvious impact on the nutrient removal,but affected microbial activities and their metabolic processes.The increased loading rate ammonium nitrogen(NH4+-N),orthophosphate(PO43--P)and chemical oxygen demand(COD)released from the side reactor were small,and had no effect on the effluent quality.The side hydrolysis and acidification decreased the nitrifying and denitrifying activities in the sidereactor,especially to nitrifying activity.While there was noobvious effect in the main reactor.The side hydrolysis and acidificationpromoted activities of phosphorus removal for sludge inthe main reactor.(3)The sludge reduction had no significant difference in SBR-SHAR process under different aeration rates.Under a low aeration condition,the total sludge reduction was about 45.4% with the contribution of 38.4% from elongated SRT,0.5% from the hydrolysis and acidification,and 6.5% from energy uncoupling.Similarly,under a high aeration condition,the total sludge reduction was about 44.5%,with the contribution of 37.5% from elongated SRT,0.4% from the hydrolysis and acidification,and 6.6% from the energy uncoupling.(4)Based on the analysis of microbial species,microbial diversity and predominant populations in the main reactor were enhanced due to the couplingof the bypass reactor.Dechloromonas possessed the highest proportion in the main reactor,while the activity of the sludge was not affected significantly.The denitrifying activity was improved by the incorporation of the bypass hydrolysis and acidification reactor.