Study On The Culture And Performance Of Dissimilatory Perchlorate Reducing Granular Sludge

Perchlorate is an important water pollutant,which has severe impact on environment and ecological environment.Biological reduction method is considered to be the most promising method to solve the pollution of perchlorate.In this study,based on the culture of mature dissimilatory perchlorate reducing granular sludge?DPR-GS?,the characteristics and rapid culture mechanism of granulation process sludge,dynamic simulation of the reactor and the recovery of hunger were studied,and established the treatment process of perchlorate-UASB.DPR-GS was cultivated by inoculating activated sludge?AS?or denitrifying granular sludge?DGS?under constant or fluctuating up-flow velocities in three identical up-flow anaerobic sludge blanket?UASB?reactors(designated as R_AS,R_DGS and R_DGS-f).The inoculated AS in the R_AS was completely granulated by day 117,while the inoculated DGS in the R_DGS and R_DGS-f maintained the crystal nucleus of granular sludge,which eventually shortened the granulation time to 99 days.In addition,the fluctuating up-flow velocity strategy can better ensure rapid cultivation of DPR-GS using inoculated DGS.Removal of ClO₄^-loading rate?PCLR?with 7.20 kg/?m³·d?,which corresponds to a 300mg/L perchlorate,occurred in all three reactors with the pH and ORP values basically stabilizing at approximately 6.5 to 7.5 and-420 to-370 mV,respectively.Changes to the extracellular polymeric substances?EPS?during formation of DPR-GS indicated that polysaccharose?PS?favored the formation of bio-aggregates,while proteins?PN?determined the granulation of sludge.The results of high-throughput sequencing indicated that Sulfurospirillum and Acinetobacter were the dominant dissimilatory perchlorate reducing bacteria?DPRB?.This study offers an efficient technology for removal of high-strength perchlorate using granular sludge in UASB reactors,thereby providing an economic and efficient alternative to conventional methods.Then the concentration of the influent matrix was raised by gradient to simulate the dynamics of the removal of perchlorate by DPR-GS.The correlation coefficient fitted by the Michaelis-Menten kinetic model was 0.956,which could better reflect the relationship between the perchlorate concentration of influent water and the perchlorate degradation rate.The maximum degradation rate v_max was 1700.76 mg/?L·h?,and the saturation constant k_s was 2740.47 mg/L.The correlation coefficient of Modified Stover-Kincannon kinetic model fitting was 0.9871,which could better reflect the relationship between the perchlorate concentration in the inlet water and the perchlorate concentration in the outlet water.The maximum perchlorate removal load constant Umax was 90.01 kg/?m³·d?,and the saturation constant K_b was 1.07?kg/?m³·d??.Finally,the effects of starvation on the physicochemical properties of granular sludge reduced by perchlorate were investigated.After 30 days of starvation,the reactor system will restore the operating conditions before the starvation period,and the reactor will return to the stable level before starvation after 18 days.Three-dimensional fluorescence analysis showed that the microorganisms in the starvation phase could promote the secretion of fluorescent substances to protect the microorganisms,and the activity of the microorganisms in the starvation phase to the reactor system could still be maintained.The results showed that the physical and chemical properties of the granular sludge reduced by perchlorate did not change significantly.This study offers an efficient technology for removal of high-strength perchlorate using granular sludge in UASB reactors,thereby providing an economic and efficient alternative to conventional methods.