Research on the effect of EPS on bacterial coagulation and granulation of flocculated sludge
In order to explore the influence of extracellular polymers substances on bacterial aggregation and flocculent sludge agglomeration and granulation,bacterial aggregation by adding LB-EPS and TB-EPS to the bacterial suspension was observed.By adding bacteria EPS to the reactor(No.1)or not(No.2),the growth changes of aerobic granular sludge in the two reactors were investigated.The aggregation and precipitation efficiency of kaolin mixed solution and bacterial suspension was carried out by simulated EPS and real EPS respectively.The results showed that the aggregation efficiency of LB-EPS for bacteria was higher than that of TB-EPS in both groups of reactors.The sludge in reactor No.1 grew rapidly and granulated.On the 70th day,the D50 of the sludge reached 377.5µm,and the maximum particle size could reach 1.4～1.5mm.From day 90 to day 100,due to insufficient organic load of sludge,the EPS concentration decreased,the granular sludge disorganized rapidly,and the sludge particle size decreased rapidly,and the D50 decreased rapidly from 296.5µm to 109.6µm.The particle size of sludge in reactor No.2 increased to 239.5µm(D50)on day 70,and continued to rise thereafter.The simulated EPS had more significant flocculation ability for kaolin,and the EPS had more significant effect on the aggregation of bacteria in bacterial suspension.It was concluded that extracellular polymers had adhesion effect on bacteria and promoted bacterial aggregation,and the adhesion effect of LB-EPS on bacteria was greater than that of TB-EPS.The addition of EPS could accelerate the granulation process of sludge.In the process of sludge granulation,the adsorption and aggregation effect of LB-EPS on free bacteria was greater than that of TB-EPS.
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维普
