Study On Excess Sludge Reduction By Using Ultrasound-hydrogen Peroxide In Lysis-Cryptic Growth System

With the development of the city economy and the acceleration ofurbanization, a lot of sewage disposal plants are completed and put into use,causing increasing sludge production. Sludge, if not properly handled, will causeserious secondary pollution environment. Therefore, it is of great significancefrom the source to reduce sludge production. Many methods have been employedaimming at reducing sludge production, and exploring effective and efficientsludge reduction technology has become a major research direction. Strengthencryptic growth is a technology depending the mechanism that microbial sludgeusing its own substrate growth process to realize the reduction of sludge, becauseof its advantages of being simple, easily controlled, as well as a widelyapplication, receiving a widespread attention.In this thesis, combined treatment of ultrasound/H2O2and SBR wasinvestigated employing the microbe strengthen cryptic growth technology. Thelytic performance of ultrasound/H2O2and the affection of sludge backflow afterlysis to the SBR treatment system were discussed. The conclusions were got asfollows:The lytic performance of ultrasound, H2O2and the combined treatment ofboth were investigated respectively. The results suggested that the combinationof ultrasound/H2O2treatment was significantly better than the separate use ofeither one, with SCOD dissolution rate increased by2~3times. Systematicallyinvestigated the influence of the ultrasound/H2O2treatment, the dosage ofhydrogen peroxide, the oxidation reaction time and pH on the lysis, the resultsshowed that ultrasonic/H2O2was synergy possible to improve the rate of lysingand shorten the reaction time. The optimum conditions for hydrogen peroxide dosage was1.5%, pH=11,20min for the reaction time.The sludge supernatantSCOD, TN, TP concentrations were increased to2138.7mg·L-1,168.35mg·L-1,12.71mg·L-1.30%,50%,70%of the sludge disposed by ultrasound/H2O2through SBRprocess were refluxed for the nest experiments the analysis of the quality of COD,TN and TP in effluent through SBR system, indicating that effluent severelydeterioration under high recirculation ratio; While under lower recirculation ratio(50%) the quality of the effluent was modestly affected, with the COD, TN andTP eliminated by88.5%,45.8%and79.3%respectively.In summary, a technology of ultrasound/H2O2–SBR for sludge reductionwas introduced in this thesis, under a proper control of the sludge return ratio,water quality was not affected severely, and a better sludge reduction can beachieved.