Charicterization Of The Pollutant Removal And Siderophores Production Of Vegetation-SBR Process

As the main functional units of the Vegetation-Activate Sludge Process(V-ASP), activated sludge, rhizosphere sludge and aquatic plants plays key roles in pollutants' assimilation and removal. At present, the decontamination ratios of the functional units in V-ASP remains controversial. In this study, stable isotope tracer technique was used to analysis the decontamination ratios of functional units to organic matter and ammonia nitrogen, as well as the assimilation intensity in the plant. In addition, the mechanism of iron scavenge in the iron-limited V-ASP was investigated.Vegetation including Canna genaralis and Cyperus alternifolius in the V-ASP, could not assimilate and remove organic matters directly. The organics assimilation ratio of activated sludge and rhizosphere sludge were close for Canna genaralis and Cyperus alternifolius based system. As the organic removal proportion of activated sludge and Rhizosphere sludge were 75.00 and 25.00% in the Canna genaralis-Activate sludge Process(CG-ASP), while was 76.90 and 23.10% in the Cyperus alternifolius-Activate Sludge Process(CA-ASP). And the organics assimilate rate were 8.1 mg C/(g TOC·d) and 7.6 mg C/(g TOC·d) respectively for activated sludge and rhizosphere sludge.The ammonia decontamination ratios of activated sludge and rhizosphe re sludge in both CG-ASP and CA-ASP was close, the ratios was 77.60 and 17.60% in the CG-ASP while was 76.80 and 19.80% in the CA-ASP. The ammonia nitrogen assimilation removal ratio of aquatic plant is 4.80% for Canna genarali, higher than 3.23% of Cyperus alternifolius. The assimilated nitrogen distribution in the root, stem and leaf varied from vegetation. The distribution proportions of total nitrogen assimilation in the root, stem and leaf were 12.50, 50.00 and 37.50% for Canna genarali, while 14.80, 69.40 and 15.80% for Cyperus alternifolius. On the other hand, the nitrogen assimilation rate of Canna genarali and Cyperus alternifolius were 0.0800 g N/(g TN·d) and 0.0042 g N/(g TN·d), and the nitrogen assimilate rate of root was higher than other parts for both plant. During the stable isotope tracer experience. The microbial community in the activated sludge and rhizosphere sludge was stable. Dominant populations were demonstrated to include Rhodocyclaceae, Comamonadaceae, Xanthomonadaceae, Planctomycetaceae, Chitinophagaceae, Nitrospiraceae, Burkholderiales incertae sedis and so on. There were significant differences in microbial community of the rhizosphere microorganisms and activated sludge.The mechanism study of iron ingestion suggested that Catechol t ype siderophores and hydroxamates are the main iron ingestion mechanism in the iron-limmited V-ASP. The total iron critical value to siderophore secretion in iron-limited system was in the range of 0.02 to 0.035 mg/L. The activity equivalent of siderophore in the effluent was 9.9 ?M. The catechol type and hydroxamates siderophore was determined after the enrichment of effluence, and many kinds of siderophores, such as Heterobactin B, Anacheline-H, 2,3-dihydroxybenzoylthreonine, Dibenarthin, Divanchrobactin, Dichrysobactin, Vibriobactin, Parabactin 2-N-methylcoprogen B,Aerobactin,Arthrobactin,Fusarinine A,Dimethylcoprogen,Exochelin MN,Fusarinine B,Heterobactin B,Rhizobactin 1021,Synechobactin A,Synechobactin B,Thiazostatin were detected by UPLC-TOF mass spectrometry. During the iron limitted operation, the pollutants removal rate had slightly decrease, but the removal rate of COD and NH3-N kept higher than 70.00 and 90.00%. The structure of microbial community obviously shifted in the iron-limited system. The abundance of Comamonadaceae was signaficantly higher than others, and the abundance of Actinomycetales gradually increased.Through the research of the decontamination rate of each functional unit of the V-ASP, it could support the modeling, stable operation of V-ASP and development of management methods. With the characterization of siderophore secretion under iron-limited V-ASP, it could help to explore novel way to improve the additional value of wastewater treatment plant or development of processes synchronous removing of heavy metals.