Research On The Response Mechanism Of Veterinary Pharmaceuticals Additives To Aerobic Granular Sludge

Frequent occurrence of Veterinary Pharmaceuticals&Feed Additives in aquaticenvironments has raised a concern about their potential effects including aquatictoxicity, genotoxicity and endocrine discruption on environment. Controlling itsemission has become a focus field. Compared to other conventional methods,biodegradation technology has several advantages such as high-efficiency, low-energyconsumption, ambient reaction conditions, and low secondary pollution, which isconsidered to be a promising method to remove such compounds.Flocculent activated sludge was used as seeding sludge, using RobenidineHydrochoride as a target pollutant. Aerobic granular sludge was cultivated in asequencing batch reactor (SBR) through regulating the operation parameters. Thedifferences in EPS compontens, variation of microbial community during the aerobicsludge granulation and toxic stress were investingated in this study, via the3D-EEMand PCR-DGGE. Main conclusions are as follows:EPS plays a crucial role in the formation and stability of aerobic granules. The valuesof protein (PN) and ratio of proteins to polysaccharides (PN/PS) in EPS extracted fromaerobic granules markedly increased along with sludge granulation. The hydrophobicityand surface charge were significantly positively correlated with PN content and PN/PSratio. The decrease of sludge settling time could stimulate the production of PN, andfavor the stability of aerobic granules. The values of protein (PN) and ratio of proteinsto polysaccharides (PN/PS) in EPS extracted from aerobic granules markedly dcreasedwhen the Robenidine Hydrochoride was added. Those values gradually restored to themature aerobic granular sludge with the degrading Robenidine Hydrochoride appeared.PCR-DGGE analysis indicated that microbial population differed obviously duringthe aerobic degradation. Most bands in the seed sludge disappeared and some newbands appeared in the aerobic granules degrading Robenidine Hydrochoride, whichrelated to the changes of microbial species, especially correlated with the developmentof Robenidine Hydrochoride-degrading microbes. The sequencing results showed thatthe organisms responsible for Robenidine Hydrochoride closely related toProteobacteria; Bacteria；Porphyromonadaceae；Chloroflexi.The Monod equation could be fitted to the experimental data of RobenidineHydrochoride by aerobic granules. The highest Robenidine Hydrochoridebiodegradation rate was up to0.94mg-Robenidine Hydrochoride/(g-VSS·h).