The Multiplying And Aggregation Of Microorganisms In Aerobic Granular Sludge Under The Strengthening Granulation Conditions

Based on the fact that aerobic granular sludge system possesses a strong resistanceto shock loading capability in order to maintain a high density of biomass in the reactor,with many advantages in terms of high concentration organic wastewater treatment inthe biodegradable organic substances and toxic and hazardous materials, etc, herein bythis article we analyze the reproduction and aggregation of cultured microorganisms inaerobic granular sludge under different operating conditions based on the research onaerobic granular sludge granulation and basic characteristics by adding coagulant inearly stage of the formation.The research implies these results:Under the intensive granulation conditions,granular sludge appears on the8thdayin the reactor with coagulant,which is2days earlier than that without coagulant.Inaddition,the grain size of granular sludge is more well-distributed.The aerobic granularsludge under the intensive granulation conditions has higher granule strength, specificgravity and lower water content.Under the intensive granulation conditions,theproportion of particles,intensity and moisture content percentage is1.1030,99.0%,95.05%respectively.Compared with granular sludge formed under usual operational condition,the intensity and specific gravity were3.2%and6.8%higher than normal respectively,but the moisture content decreased by1.0%.Implied by the microorganisms’ aggregation in the process of granule forming,as a resultof additional coagulant,the microorganisms aggregated quickly in the initial stage ofgranule forming,but when the addition of coagulant stopped,the biomass decreased. With the growing of granular,the biomass increased and tended to be consistent with theaggregation of microorganisms of granular sludge in usual operational condition.Whenformation of granular completed,the sludge concentration would maintain7g/L,the totalnumber of bacteria would maintain above107cfu/g.By analyzing the EPS content in granular sludge under different operationalconditions,the result displayed that under usual operational conditon,the EPS contentincreased as microorganisms aggregating.But under the intensive granulation conditions,the EPS content has little relationship with biomass.Therefore it is obvious that under theintensive granulation conditions, the microorganisms aggregation mainly due to thefunction of coagulant.After improved the reactor influent COD load,both of the granular sludge reactorhave a large number of filamentous bacteria growth,number of filamentous fungi inmorethan106cfu/g.The total number of bacteria Under the intensive granulationconditions and operational conditions also reached109cfu/g and108cfu/g,respectively.But the granular sludge sedimentation performance degradation is obvious.Therefore,ahigh COD load Would stimulate the growth of microorganisms,but the formation of thestructure of the particles Will be looser.After the reactor influent pH is adjusted to from4to5to7to8,the number offilamentous fungi in both of the granular sludge reactors drops rapidly from106cfu/g to104cfu/g.Under the intensive granulation conditions of granular sludge,thesedimentation performance increased from28.1m/h to35.3m/h,the settlement ofparticles under the operational conditions performance is improved from25.5m/h to33.1m/h.This implies that under acidic conditions promote the growth of filamentousfungi, while under neutral conditions the excessive growth of the filamentous bacteria isunder control.