Performance and microbial community analysis of bioaugmented activated sludge for nitrogen-containing organic pollutants removal

Nitrogen-containing organic pollutants(quinoline,pyridine and indole)are widely distributed in coking wastewater,and bioaugmentation with specific microorganisms may enhance the removal of these recalcitrant pollutants.The bioaugmented system(group B)was constructed through inoculation of two aromatics-degrading bacteria,Comamonas sp.Z1(quinoline degrader)and Acinetobacter sp.JW(indole degrader),into the activated sludge for treatment of quinoline,indole and pyridine,and the non-bioaugmented activated sludge was used as the control(group C).Both groups maintained high efficiencies(>94%)for removal of nitrogen-containing organic pollutants and chemical oxygen demand(COD)during the long-term operation,and group B was highly effective at the starting period and the operation stage fed with raw wastewater.High-throughput sequencing analysis indicated that nitrogen-containing organic pollutants could shape the microbial community structure,and communities of bioaugmented group B were clearly separated from those of non-bioaugmented group C as observed in non-metric multidimensional scaling(NMDS)plot.Although the inoculants did not remain their dominance in group B,bioaugmentation could induce the formation of effective microbial community,and the indigenous microbes might play the key role in removal of nitrogen-containing organic pollutants,including Dokdonella,Comamonas and Pseudoxanthomonas.Phylogenetic Investigation of Communities by Reconstruction of Unobserved States(PICRUSt)analysis suggested that bioaugmentation could facilitate the enrichment of functional genes related to xenobiotics biodegradation and metabolism,probably leading to the improved performance in group B.This study indicated that bioaugmentation could promote the removal of nitrogen-containing organic pollutants,which should be an effective strategy for wastewater treatment.

Identification and characterization of Fe_(3)O_(4)/peroxodisulfate advanced oxidation products from sulfameter

Sulfonamides(SAs)are one of the most widely used antibiotics and their residuals in the environment could cause some negative environmental issues.Advanced oxidation such as Fenton-like reaction has been widely applied in the treatment of SAs polluted water.Degradation rates of 95%-99.7%were achieved in this work for the tested 8 SAs,including sulfisomidine,sulfameter(SME),phthalylsulfathiazole,sulfamethoxypyridazine,sulfamonomethoxine,sulfisoxazole,sulfachloropyridazine,and sulfadimethoxine,in the Fe_(3)O_(4)/peroxodisulfate(PDS)oxidation system after the optimization of PDS concentration and p H.Meanwhile,it was found that a lot of unknown oxidation products were formed,which brought up the uncertainty of health risks to the environment,and the identification of these unknown products was critical.Therefore,SME was selected as the model compound,from which the oxidation products were never elucidated,to identify these intermediates/products.With liquid chromatography-high resolution tandem mass spectrometry(LC-HRMS/MS),10 new products were identified,in which 2-amino-5-methoxypyrimidine(AMP)was confirmed by its standard.The investigation of the oxidation process of SME indicated that most of the products were not stable and the degradation pathways were very complicated as multiple reactions,such as oxidation of the amino group,SO_(2)extrusion,and potential cross-reaction occurred simultaneously.Though most of the products were not verified due to the lack of standards,our results could be helpful in the evaluation of the treatment performance of SAs containing wastewater.