Performance And Microbial Community Of GSBR And HBR Treating Municipal Wastewater

With most of the wastewater treatment plants (WWTP) are facing the differentyof being uable to meet the water discharge criteria, how to improve its treatmentperformance without making much changes is currently a serious problem to besolved in China. With the advantages of maintaining high biomass concentration andfewer changes to existing processes, granular SBR (GSBR) and hybrid biologicalprocess (HBR) are much more suitable for WWTP upgrade. So, the municipalwastewater treatment efficiency, process parameters optimization and pollutantremoval mechanisms of GSBR and HBR was studied in this paper. Microbialcommunity of HBR treating industrial wastewater was also analyzed by usingmolecular biology techniques.Firstly, experiment of aerobic granular sludge was carried out in ananaerobic/aerobic pilot-scale GSBR reactor with a cylindrical shape. In the GSBR,small size granular appeared after72d’s cultivation. And upon the best operatingconditions, the average removal rates of COD, NH4+-N, TN and TP were91.63%,74.02%,68.42%and96.41%, respectively. In horizontal-flow SBR, simultaneousnitrogen and phosphorus removal process was realized, with the average removalrates of COD, NH4+-N, TN and TP were90.1%,87.3%,60.2%and89.3%. Operatingdata of GSBR and horizontal-flow SBR showed that organic loading rate and reactorconfiguration were the most important factors of the formation of aerobic granules.Secondly, treatment performances of municipal wastewater and industrial waterin HBR were studied in this research, by using a newly designed bio-carrier. In theHBR, biofilm biomass accounted for25%of total biomass. COD, NH4+-N and TNremoval rates reached85%,90%and60%. Experiment on industrial wastewatertreatment by HBR system was carried out for6months. Experiment results showedthat biofilm biomass accounted for more than40%of total biomass. The averageeffluent COD, NH4+-N and TN concentrations were65.3mg/L,0.86mg/L and5.48mg/L. Residual COD was almost contributed by non-biodegradable organicmatters. N-removal was realized mainly by pre-denitrification and aerobicdenitrification processes. Finally, using PCR-DGGE and FISH techniques, the paper revealed thecharacteristics of microbial community in HBR. The results showed that the HBRsystem has high microbial community diversity. The microorganisms which were ableto degration of organics had gradually been enriched in suspended-growth andattached–growth sludge. AOB group was basically belonged to Nitrosospira spp. andNitrosomonas spp. The Nitrobacter spp., Pseudomonas spp. and Nitrospira spp. werecommon NOB species both in suspended sludge and biofilm. β-proteobacteria wasthe dominant denitrifying species. In the process of experiment, the proportion ofAOB, NOB and denitrifying bacteria gradually increased in HBR.