Effect Of Vinyl Polymers On The Microbial Community Of Aerobic Activated Sludge

The biodegradability assessment and environmental friendly assessment ofindustrial chemicals had been a problem to be solved of chemical management inChina, as one important kind leather chemicals, the research of biodegradabilitywas less. This paper take the vinyl polymer tanning agents and finishing agent asthe object, the degradation in the aerobic biological treatment process and itsinfluence on microbial community structure of activated sludge werestudied.This study choosed three different structure of vinyl polymer tanningagent, they were PDM (number LY-1), PDM-AA-AM-HEA (number LY-5) andthe composite product of PDM-AA-AM-HEA and nano ZnO (number LY-8), andselected the poly acrylate (LJL-2) and composite product of poly acrylate withnanometer ZnO finishing agent (LJL-3), set up500mg/L and1000mg/L twoconcentration gradient, using aerobic activated sludge method under thecondition of the laboratory simulation, the degradation experiment carried out for30days, we examined the degradability of the materials and their influence onmicrobial activity by the detect of CODCrconcentrations in the water, the changeof active sludge dehydrogenase and the total protein concentration, on this basis,we analyzed the succession of microbial community structure in the degradationprocess by the use of PCR-DGGE method.The results showed that the three different structure of vinyl type of tanningagent, LY-8of nano composite materials showed better degradability than theprecursor LY-5(PDM-AA-AM-HEA), the degradation rate of LY-5was thelowest in the three materials.Under the concentration of500mg/L, thedegradation rate of LY1, LY-5and LY8were43.5%,34.7%and58.3%，respectively in30d time, their degradation rate were respectively47.6%,-5.1%and54.8%under the concentration of1000mg/L. Three kinds of tanning agentin the process of degradation produced a significant inhibitory effect to microorganisms in activated sludge by varying degrees. The dehydrogenase andprotein concentration were both low of LY-5groups under the two concentrationgradient, active sludge disintegration phenomenon happened at the end of theexperiment. Inhibition of aerobic activated sludge of LY-1were relevant with theconcentration of LY-1, the dehydrogenase and protein concentration increasedunder the low concentration of LY-1. In the degradation process of LY-8groupthe protein concentration and dehydrogenase had delayed to rise.Compared withthe above three kinds of tanning agent, the degradability of poly acrylic ester(LJL-2) and its ZnO composite finishing agent (LJL-3) were better, at thebeginning of the experiment, the LJL-2and LJL-3CODCrconcentrations werefalling fast, they were biodegraded after a large number of adsorption, twofinishing agent on the effect of protein concentration and dehydrogenaseconcentration in the sludge and glucose to cultivate the experimental results arebasically identical, reflecting the good biodegradability and smaller effect oninhibition of microorganisms in the sludge.PCR-DGGE was used to study the sludge microbial community structure inthe process of degradation, which had shown that microbial communitystructures of the original activated sludge was rich, community distribution waswider.After5kinds of chemicals joined in the activated sludge, the proportion ofbacteroidetes in the sludge diminished. The bacteroidetes was absolutelyadvantage bacterium group in the sludge microbial community, the addition ofthe polymer changed the growth environment of the microorganisms existed,suggests the weaken environment adaptability. Compared with poly acrylic acidesters finishing agent (LJL-2and LJL-3), three kinds of tanning influenced onmicrobial community structure were relatively obvious, and led to disappear ofthe green fungus in the microbial community; Among them, the disappeared ofLY-1, LY-5groups occurred in120h to720h, LY-8was in0h to120h. Thoughthe degradability of LY-8in LY series was the best, but the inhibitory to the greenbacteria was the strongest. The study showed that the proportion of thick wallbacteria in LY series increased during training, especially in the strongestinhibitory of LY-5the added proportion was the largest, so thick wall under thisexperimental condition belong to strong resistance in this experiment, polyacrylic ester (LJL-2) and its ZnO composite agent (LJL-3) had little impact on the microbial community structure, green bacteria, thick wall door had noobvious change in the process of degradation, suggested that existed of LJLseries agent did not cause big changes to the microorganism, the environmentstill suitable for microbial growth.In this study, the two characteristic bacteria included deformation door andthick wall door were selected in the process of microbial succession: klebsiellapneumonia bacteria and bacillus, the pure strains of toxicology experiments wereproceeded. It was found that: after add five selected materials and there is no bigchange on pH, but bacteria klebsiella pneumonia were significantly inhibited bythese agents, inhibition effect was proportional to the concentration of the added.LY tanning agent inhibitory effect on bacillus was not obvious, while LJLinhibited significantly, the results were consistent with thick wall fungus hadhigh tolerance with LY series materials. Mixed two kinds of bacteria, alsoshowed obvious inhibition of bacillus, reflected the thick wall door had highadaptability of LY series material.