反硝化除磷工艺中亚铁协同除磷效能与机理研究
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摘要
反硝化除磷SBR系统中长期投加Fe~(2+)能够强化系统除磷脱氮效果。Fe~(2+)浓度为3.0mg/L条件下,R_0(空白)、R_1(厌氧初期投加)、R_2(缺氧初期投加)出水硝氮浓度分别为7.05,5.87,6.24 mg/L。缺氧吸磷后磷浓度分别为6.04,1.03,1.15 mg/L;经后曝气进一步好氧除磷后,出水磷浓度分别为1.26,0.08,0.06 mg/L。反硝化除磷系统Fe~(2+)协同除磷药剂利用率较高,R_1和R_2中铁磷摩尔比(投加Fe~(2+)量与除磷增加量)分别为0.34:1和0.35:1,远低于Fe~(2+)化学除磷的最佳铁磷摩尔比(>2:1)。Fe~(2+)停止投加后系统表现出了持续的强化脱氮除磷效果,厌氧初期投加优于缺氧初期。反硝化除磷系统中长期投加Fe~(2+)盐能够改善污泥沉降性能,相对于R_0,R_1和R_2中污泥SVI平均降低了16.23%和18.92%,污泥絮体变得更加密实。协同机制除了化学作用,还存在生物协同作用。
Dosage of ferrous ion could enhance the nitrogen and phosphorus removal performance of the denitrifying phosphorus removal SBR. Under the dosage concentration of 3.0 mg/L, effluent nitrate concentration of R_0(without Fe~(2+) dosing), R_1(dosing at the beginning of anaerobic phase) and R_2(dosing at the beginning of anoxic phase) was7.05 mg/L, 5.87 mg/L and 6.24 mg/L respectively. Effluent TP concentration after anoxic phase was 6.04 mg/L,1.03 mg/L and 1.15 mg/L, and then was decreased to 1.26 mg/L, 0.08 mg/L and 0.06 mg/L after the subsequent aerobic phosphorus removal. The chemical utilization of Fe~(2+) efficiency is high, the mole ratio of iron(Fe~(2+) dosage concentration) and phosphate(increment of phosphorus removed) of R_1 and R_2 are 0.34: 1 and 0.35: 1, which are far below the optimal ratio of chemical phosphorus removal(>2: 1). The system demonstrated the sustained nitrogen and phosphorus removal enhancement, and R_1 was better than R_2. Moreover, the sludge settling performance was also improved. Compared with the R_0, SVI of R_1 and R_2 was decreased by 16.23% and 18.92%, and sludge flocs were much denser. The synergistic mechanism consisted of the chemical reaction and also biological synergism.
Dosage of ferrous ion could enhance the nitrogen and phosphorus removal performance of the denitrifying phosphorus removal SBR. Under the dosage concentration of 3.0 mg/L, effluent nitrate concentration of R_0(without Fe~(2+) dosing), R_1(dosing at the beginning of anaerobic phase) and R_2(dosing at the beginning of anoxic phase) was7.05 mg/L, 5.87 mg/L and 6.24 mg/L respectively. Effluent TP concentration after anoxic phase was 6.04 mg/L,1.03 mg/L and 1.15 mg/L, and then was decreased to 1.26 mg/L, 0.08 mg/L and 0.06 mg/L after the subsequent aerobic phosphorus removal. The chemical utilization of Fe~(2+) efficiency is high, the mole ratio of iron(Fe~(2+) dosage concentration) and phosphate(increment of phosphorus removed) of R_1 and R_2 are 0.34: 1 and 0.35: 1, which are far below the optimal ratio of chemical phosphorus removal(>2: 1). The system demonstrated the sustained nitrogen and phosphorus removal enhancement, and R_1 was better than R_2. Moreover, the sludge settling performance was also improved. Compared with the R_0, SVI of R_1 and R_2 was decreased by 16.23% and 18.92%, and sludge flocs were much denser. The synergistic mechanism consisted of the chemical reaction and also biological synergism.
引文
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[2]Tsuneda S,Ohno T,Soejima K,et al.Simultaneous nitrogen and phosphorus removal using denitrifying phosphate-accum-ulating organisms in a sequencing batch reactor[J].Biochemical Engineering Journal,2006,27(3):191-196.
[3]Girard L,Encina P,Rodriguez E R.Process Performance and Polyphosphate-Accumulating Organism-Glycogen-Accumulating Organism Communities in an Anaerobic/Anoxic/Oxic System Operated with Different Carbon Sources[J].Water Environment Research,2012,84(4):354-361.
[4]Lv X,Li J,Sun F,et al.Denitrifying phosphorus removal for simultaneous nitrogen and phosphorus removal from wastewater with low C/N ratios and microbial community structure analysis[J].Desalination and Water Treatment,2016,57(4):1890-1899.
[5]李瑞鑫.污水处理ANAO工艺侧流除磷及污泥减量技术研究[D].哈尔滨:哈尔滨工业大学,2013.
[6]周斌,王桂玉,占国将.化学药剂除磷试验初探[J].净水技术,2015(1):25-28.
[7]张萌,邱琳,于晓晴,等.亚铁盐与高铁盐除磷工艺的对比研究[J].高校化学工程学报,2013(3):519-525.
[8]谢经良,刘娥清,赵新,等.不同形态铁盐的除磷效果[J].环境工程学报,2012,6(10):3429-3432.
[9]姚婧梅,张智,任丽平,等.化学除磷中Fe(Ⅲ)和Fe(Ⅱ)盐对活性污泥系统的影响[J].中国给水排水,2012,28(9):20-25.
[10]Li T,Wang H,Dong W,et al.Performance of an anoxicreactor proposed before BAF:Effect of ferrous sulfate on enhancing denitrification during simultaneous phosphorous removal[J].Chemical Engineering Journal,2014,248:41-48.
[11]Wang H,Dong W,Li T,et al.Enhanced synergistic denitrification and chemical precipitation in a modified BAF process by using Fe~(2+)[J].Bioresource Technology,2014,151:258-264.
[12]Nielsen P H R.The significance of microbial Fe(III)reduction in the activated sludge process[J].Water Science and Technology,1996,34(5-6):129-136.
[13]Oikonomidis I,Burrows L J,Carliell-Marquet C M.Mode of action of ferric and ferrous iron salts in activated sludge[J].Journal of Chemical Technology and Biotechnology,2010,85(8):1067-1076.
[14]Wang Y,Qin J,Zhou S,et al.Identification of the function of extracellular polymeric substances(EPS)in denitrifying phosphorus removal sludge in the presence of copper ion[J].Water Research,2015,73:252-264.
[15]Zhang H,Fang W,Wang Y,et al.Phosphorus Removal in an Enhanced Biological Phosphorus Removal Process:Roles of Extracellular Polymeric Substances[J].Environmental Science&Technology,2013,47(20):11482-11489.