| This paper was engaged in the study of the characteristic features, thepollutant-removing efficiency of aerobic granular sludge under the strengtheninggranulation conditions. Some experiments about the kinetics of substrate degradationand biomass growth by aerobic granular sludge under the strengthening granulationconditions were investigated. The effects of PAC and pH on re-granulation of brokenaerobic granules under the strengthening granulation conditions were discussed.A series of experiments were conducted by adding coagulant (PAC) to the SBR inthe beginning stage of the granular sludge formation in hoping to reduce the formulatingtime. And, on its basis, the characteristic features and COD and NH4+–N removalefficiency of aerobic granular sludge in strengthening the granulation conditions wereinvestigated. As compared with the control treatment, the results revealed that thespecific gravity, the integrity coefficient (IC) and the water content of the matureaerobic granular sludge under the strengthening granulation conditions were1.103,99.14%and95.05%, respectively. When comparing it with the aerobic granular sludgein the control group, it was found that the specific gravity and integrity coefficient (IC)of the mature sludge under the strengthening granulation conditions tended to increaseby1.04%and2.05%, with the water content of the aerobic granular sludge understrengthening granular conditions had decreased by6.52%. During the stable workingperiod of the reactor, the mean removal efficiencies of COD and NH4+–N of aerobicgranular sludge in the strengthening granulation conditions should be able to reach94%and71.26%, which were closer to those of the control treatment, bur it could have muchbetter stability than that of the control treatment. The analysis through typical cycling testing showed that aerobic granular sludge in the strengthening granulation conditionstended to achieve perfect simultaneous COD and the NH4+–N removing efficiency.The kinetic coefficients of Ks, Vmaxwere449.49mg·L-1,1.43h-1respectively foraerobic granular sludge under the strengthening granulation conditions,which could beincreased by1.1times,1.05times as compared with that of the control group. Thekinetic coefficients of Y and Kdwere0.161kgMLVSS/kgCOD and0.0304d-1respectively for aerobic granular sludge under the strengthening granulation conditions,which were slightly better than that of the control group.The results showed that physical characteristics of aerobic granular sludge with PACwere superior to regular aerobic granular sludge without PAC.When comparing it withthe aerobic granular sludge in the control group, it was found that the specific gravityand integrity coefficient (IC) of the mature granular sludge with PAC tended to increaseby3.82%and1.68%, with the water content of the aerobic granular sludge haddecreased by0.50%,which reveals that coagulant PAC strengthen characteristics ofbreaking-reformulation aerobic granular sludge. Despite two kinds of aerobic granularsludge restore well COD degradation ability in mature period, the average removal rateof COD were96.47%,95.90%respectively, however, the average removal rate of NH4+-N were only66.02%and64.79%respectively. The pollutant removal efficiency ofthese breaking-reformulation aerobic granular sludge were slightly less than thoese oforiginal aerobic granular sludge. This proved PAC could promote thebreaking-reformulation process of aerobic granular sludge under the strengtheninggranulation conditions, but it couldn’t make it back to its initial state.The results showed that the broken sludge had reassembled into a large number ofbig and regular particles in R1until the54thcycle. The specific gravity, the integritycoefficient (IC) and the water content of breaking-reformulation aerobic granularsludge under the strengthening granulation conditions were1.032,96.48%and96.72%,respectively. The specific gravity, the integrity coefficient (IC) and the water content ofbreaking-reformulation aerobic granular sludge in R2were1.015，95.06%and97.91%,respectively. As a whole, the broken aerobic granular sludge in R1recovered better. Atthe end of the54thcycle, the removal rate of COD of breaking-reformulation aerobicgranules in R1and R2were100.00%,99.60%respectively,and the average removal rate of NH4+-N were100.00%,76.21%respectively. The ammonia nitrogen removalabilities were both superior to the initial aerobic granular sludge. When pH value wasbetween7.74~8.44, pH significantly promoted NH4+-N removal ability ofbreaking-reformulation aerobic granular sludge under the strengthening granulationconditions. |
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