Fe~(3+)在A~2O工艺缺氧区的转化规律及其对污泥絮凝性的影响
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摘要
为了研究铁元素对A~2O工艺污泥絮凝性的影响,考察Fe~(3+)在污泥上清液、胞外聚合物(extracellular polymeric substances,EPS)与底泥(Pellet)中的分布和迁移转化规律,结合三维荧光光谱(3D-EEM)、原子吸收和X射线衍射仪(XRD)分析Fe的存在形态和结构特征,揭示Fe~(3+)与微生物代谢产物的作用机制,探索Fe~(3+)对脱氮除磷效率的影响。结果表明:低浓度Fe~(3+)(<10 mg·L~(-1))能够提高COD和TN去除率,促进微生物活性,增强污泥生物絮凝性;高浓度Fe~(3+)(10～40 mg·L~(-1))则抑制微生物活性,使EPS总量升高,污泥絮体脱稳,LB、TB层PN/PS是影响污泥絮凝性的关键因素;Fe~(3+)的投加强化生物除磷效率,当Fe~(3+)浓度为40 mg·L~(-1)时,TP去除率为93%。Fe~(3+)在污泥混合液中的分布规律为TB>上清液>LB>SMP,Fe~(3+)在生物体内富集累积,能够改变EPS各层的组分。
To study the effect of iron on the flocculation of A~2O process sludge, the distribution and migration and tranformation of Fe~(3+) in sludge supernatant, extracellular polymeric substances(EPS) and sediment(Pellet) were investigated. A large amount of wastewater containing Fe~(3+) was generated in the rapidly developed industries such as metallurgy, electroplate and mineral separation. Fe~(3+) entered the sewage biological treatment system and could affect the sludge biological flocculation and the removal of COD, TN and TP. Information on the morphology,structure change, migration and conversion of iron ions in the anaerobic, anoxic and oxic sludge was scrae. The occurrence form and structural characteristics of iron ions were analyzed and the interaction mechanism between Fe~(3+) and microbial metabolites was revealed based on the analyses of three-dimensional excitation(3D-EEM), atom absorption and X-ray diffraction(XRD). The effect of Fe~(3+) on the denitrification and phosphorus removal was explored. The results showed that low concentration of Fe~(3+)(<10 mg· L~(-1)) could improve COD and TN removal,promote microbial activity and enhance the biological flocculation of sludge. When Fe~(3+) increased from 0 to 10 mg·L~(-1),the removal efficiency of COD and TN increased from 42% and 37% to 60% and 45%, respectively, while the dehydrogenase activity increased from 20.09 mg ·(L · h)~(-1) to 31.91 mg ·(L · h)~(-1). The flocculation ability(FA)increased from 30% to 53% and the maximum sludge particle size was 43.3 μm. High concentration of Fe~(3+) could inhibit microbial activity, increase EPS content and induce sludge deflocculation. When Fe~(3+) concentration increased from 10 mg · L~(-1) to 40 mg ·~(-1), the removal efficiency of COD and TN decreased by 28% and 34%,respectively. Protein(PN)/polysaccharide(PS) in loosely bound EPS(LB) and tightly bound EPS(TB) was the key factor affecting the flocculation of sludge. Fe~(3+) addition could enhance TP removal efficiency and it was 93% when Fe~(3+) was 40 mg · L~(-1). Fe~(3+) concentration distribution in the sludge was TB>supernatant>LB>soluble microbial products(SMP), and the main form of Fe element in the sludge was Fe~(3+). The iron content of different forms changed with the increase of Fe~(3+) concentration. In addition, Fe~(3+) could enrich and accumulate in the microorganism cells and could change the composition of EPS layers.
To study the effect of iron on the flocculation of A~2O process sludge, the distribution and migration and tranformation of Fe~(3+) in sludge supernatant, extracellular polymeric substances(EPS) and sediment(Pellet) were investigated. A large amount of wastewater containing Fe~(3+) was generated in the rapidly developed industries such as metallurgy, electroplate and mineral separation. Fe~(3+) entered the sewage biological treatment system and could affect the sludge biological flocculation and the removal of COD, TN and TP. Information on the morphology,structure change, migration and conversion of iron ions in the anaerobic, anoxic and oxic sludge was scrae. The occurrence form and structural characteristics of iron ions were analyzed and the interaction mechanism between Fe~(3+) and microbial metabolites was revealed based on the analyses of three-dimensional excitation(3D-EEM), atom absorption and X-ray diffraction(XRD). The effect of Fe~(3+) on the denitrification and phosphorus removal was explored. The results showed that low concentration of Fe~(3+)(<10 mg· L~(-1)) could improve COD and TN removal,promote microbial activity and enhance the biological flocculation of sludge. When Fe~(3+) increased from 0 to 10 mg·L~(-1),the removal efficiency of COD and TN increased from 42% and 37% to 60% and 45%, respectively, while the dehydrogenase activity increased from 20.09 mg ·(L · h)~(-1) to 31.91 mg ·(L · h)~(-1). The flocculation ability(FA)increased from 30% to 53% and the maximum sludge particle size was 43.3 μm. High concentration of Fe~(3+) could inhibit microbial activity, increase EPS content and induce sludge deflocculation. When Fe~(3+) concentration increased from 10 mg · L~(-1) to 40 mg ·~(-1), the removal efficiency of COD and TN decreased by 28% and 34%,respectively. Protein(PN)/polysaccharide(PS) in loosely bound EPS(LB) and tightly bound EPS(TB) was the key factor affecting the flocculation of sludge. Fe~(3+) addition could enhance TP removal efficiency and it was 93% when Fe~(3+) was 40 mg · L~(-1). Fe~(3+) concentration distribution in the sludge was TB>supernatant>LB>soluble microbial products(SMP), and the main form of Fe element in the sludge was Fe~(3+). The iron content of different forms changed with the increase of Fe~(3+) concentration. In addition, Fe~(3+) could enrich and accumulate in the microorganism cells and could change the composition of EPS layers.
引文
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[12]张兰河,田蕊,郭静波,等.NaCl盐度对A2/O工艺缺氧区胞外聚合物及生物絮凝性的影响[J].环境科学,2018,39(9):4281-4288.Zhang L H,Tian R,Guo J B,et al.Effect of NaCl salinity on extracellular polymeric substances and bioflocculation of anoxic sludge in A2/O process[J].Environmental Science,2018,39(9):4281-4288.
[13]张海丰,于海欢,问志勇,等.铁离子分布规律及其对MBR微生物代谢产物的影响[J].硅酸盐通报,2016,35(3):784-788.Zhang H F,Yu H H,Wen Z Y,et al.Distributions of Fe3+and its influence on microbial products in membrane bioreactor[J].Bulletin of the Chinese Ceramic Society,2016,35(3):784-788.
[14]Zhang H F,Wang Z P,Zhang L H,et al.Impact of sludge cation distribution pattern on its filterability in membrane bioreactor[J].Bioresource Technology,2014,171:16-21.
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[17]宋照亮,刘丛强,彭渤,等.逐级提取(SEE)技术及其在沉积物和土壤元素形态研究中的应用[J].地球与环境,2004,32(2):70-77.Song Z L,Liu C Q,Peng B,et al.Step-by-Step Extraction(SEE)technology and its application in sediment and soil element morphology research[J].Earth and Environment,2004,32(2):70-77.
[18]寇明旭,刘全阳.金属离子对活性污泥微生物影响研究进展[J].山西建筑,2007,33(5):176-177.Kou M X,Liu Q Y.Researching process of the influence of metallic ion on active sludge microbe[J].Shanxi Architeture,2007,33(5):176-177.
[19]Pinojelcic S A,Hong S M,Park J K.Enhanced anaerobic biodegradability and inactivation of fecal coliforms and Salmonella spp.in wastewater sludge by using microwaves[J].Water Environment Research A Research Publication of the Water Environment Federation,2006,78(2):209-216.
[20]陈睿.Fe3+存在下好氧活性污泥处理制浆中段废水的研究[D].青岛:青岛科技大学,2014.Chen R.Study on treatment of mid-stage pulping effluent by aerobic activated sludge in the presence of Fe3+[D].Qingdao:Qingdao University of Science and Technology,2014.
[21]易维洁,曲东,贾蓉.不同淹水时间水稻土微生物群落的Fe(Ⅲ)还原能力及其与脱氢酶活性的关系[J].应用基础与工程科学学报,2012,20(5):768-776.Yi W J,Qu D,Jia R.Relationships between Fe(Ⅲ)reduction and dehyrogenase activity of microbial communities in paddy soil during different flooding periods[J].Journal of Basic Science and Engineering,2012,20(5):768-776.
[22]Zhang Y,Li B,Xu R X,et al.Effects of pressurized aeration on organic degradation efficiency and bacterial community structure of activated sludge treating saline wastewater[J].Bioresource Technology,2016,222:182-189.
[23]Rabi S,Nakhl A G.Impact of calcium on the membrane fouling in membrane bioreactors[J].Journal of Membrane Science,2008,314(1):134-142.
[24]Cornell R M,Schwertmann U.The iron oxides:structure,properties,reactions,occurrence and uses[J].Mineralogical Magazine,1997,61(5):740-741.
[25]Li J,Zhai S Y,Wang Y E,et al.The research of reduction characteristics of Fe(III)dissimilated by different activated sludge[J].Advanced Materials Research,2013,663:1011-1016.
[26]Oikonomidis I,Burrows L J,Carliellmarquent 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.
[27]Hu X,Chen K,Lai X,et al.Effects of Fe(III)on biofilm and its extracellular polymeric substances(EPS)in fixed bed biofilm reactors[J].Water Science&Technology A Journal of the International Association on Water Pollution Research,2016,73(9):2060.
[28]Li H,Wen Y,Cao A,et al.The influence of multivalent cations on the flocculation of activated sludge with different sludge retention times[J].Water Research,2014,55(2):225-232.
[29]Wang Z,Gao M C,Wang Z,et al.Effect of salinity on extracellular polymeric substances of activated sludge from an anoxic-aerobic sequencing batch reactor[J].Chemosphere,2013,93(11):2789-2795.
[30]马旭阳.黄河水体沉积物中铁与磷的形态分布及相关分析[D].呼和浩特:内蒙古师范大学,2015.Ma X Y.Distribution and correlation analysis of phosphorus and iron fractions in sediments of the Yellow River[D].Hohhot:Inner Mongolia Normal University,2015.
[31]隆茜,张经.陆架区沉积物中重金属研究的基本方法及其应用[J].海洋湖沼通报,2002,25(3):25-35.Long Q,Zhang J.The method of heavy metals study in shelf sediments and its application[J].Transaction of Oceanology and Limnology,2002,25(3):25-35.
[32]钱风越.Fe3O4纳米颗粒对厌氧消化产甲烷过程的影响研究[D].哈尔滨:哈尔滨工业大学,2015.Qian F Y.Effect of magnetite nanoparticles on methanogenesis by anaerobic bigestion[D].Harbin:Harbin Institute of Technology,2015.
[33]Wang X,Qian J,Li X,et al.Influences of sludge retention time on the performance of submerged membrane bioreactors with the addition of iron ion[J].Desalination,2012,296(25):24-29.
[34]何志江,张源凯,王洪臣,等.活性污泥絮凝沉降速率计算方法研究[J].环境污染与防治,2015,37(12):35-40.He Z J,Zhang Y K,Wang H C,et al.Study on calculation method of flocculation sedimentation rate of activated sludge[J].Environmental Pollution and Control,2015,37(12):35-40.
[35]兰善红,李慧洁,王传路,等.Fe3+对好氧活性污泥理化特性的影响[J].中国造纸学报,2015,30(4):18-21.Lan S H,Li H J,Wang C L,et al.Effect of Fe3+on physicochemical properties of aerobic activated sludge during domestication by pulping middle-stage effluent[J].Transactions of China Pulp and Paper,2015,30(4):18-21.
[36]Abbasi A,Amiri S.Emulsifying behavior of an exopolysaccharide produced by enterobacter cloacae[J].African Journal of Biotechnology,2008,7(10):1574-1576.
[2]李浩,闫玉洁,谢慧君,等.Fe3+对同步硝化反硝化过程氮元素迁移转化及N2O释放的影响[J].环境科学,2015,36(4):1392-1398.Li H,Yan Y J,Xie H J,et al.Effect of ferric iron on nitrogen immigration and transformation and nitrous oxide emission during simultaneous nitrification denitrification process[J].Environmental Science,2015,36(4):1392-1398.
[3]雷绍民,王欢,王恩文,等.工业废水中多金属离子的吸附净化[J].环境工程学报,2013,7(2):513-517.Lei S M,Wang H,Wang E W,et al.Adsorption and purification of multiple metal ions in industrial wastewater[J].Chinese Journal of Environmental Engineering,2013,7(2):513-517.
[4]龙腾锐,孟雪征,赖震宏.Fe3+对活性污泥系统的影响[J].给水排水,2004,30(12):15-17.Long T R,Meng X Z,Lai Z H.Fe3+effect on activated sludge system[J].Water and Wastewater Engineering,2004,30(12):15-17.
[5]Wang Y,Leslie G L,Waite T D.Impact of iron dosing of membrane bioreactors on membrane fouling[J].Chemical Engineering Journal,2014,252(18):239-248.
[6]Li H,Wen Y,Cao A,et al.The influence of additives(Ca2+,Al3+,and Fe3+)on the interaction energy and loosely bound extracellular polymeric substances(EPS)of activated sludge and their flocculation mechanisms[J].Bioresource Technology,2012,114(2):188-194.
[7]于海欢.Fe3+对MBR运行效能影响解析[D].吉林:东北电力大学,2016.Yu H H.Analysis of the influence of Fe3+on MBR performance[D].Jilin:Northeast Electric Power University,2016.
[8]Wang X M,Waite T D.Iron speciation and iron species transformation in activated sludge membrane bioreactors[J].Water Research,2010,44(11):3511-3521.
[9]Raymond K N,Allred B E,Sia A K.Coordination chemistry of microbial iron transport[J].Accounts of Chemical Research,2015,48(9):2496-2505.
[10]操家顺,江心,方芳,等.Fe3+对活性污泥胞内贮存物和胞外聚合物的影响[J].华中科技大学学报(自然科学版),2014,42(5):101-106.Cao J S,Jiang X,Fang F,et al.Influences of Fe3+on intracellular storage and extracellular polymeric substance of activated sludge[J].Journal of Huazhong University of Science and Technology,2014,42(5):101-106.
[11]Qu F,Liang H,He J,et al.Characterization of dissolved extracellular organic matter(dEOM)and bound extracellular organic matter(bEOM)of Microcystis aeruginosa and their impacts on UF membrane fouling[J].Water Research,2012,46(9):2881-2890.
[12]张兰河,田蕊,郭静波,等.NaCl盐度对A2/O工艺缺氧区胞外聚合物及生物絮凝性的影响[J].环境科学,2018,39(9):4281-4288.Zhang L H,Tian R,Guo J B,et al.Effect of NaCl salinity on extracellular polymeric substances and bioflocculation of anoxic sludge in A2/O process[J].Environmental Science,2018,39(9):4281-4288.
[13]张海丰,于海欢,问志勇,等.铁离子分布规律及其对MBR微生物代谢产物的影响[J].硅酸盐通报,2016,35(3):784-788.Zhang H F,Yu H H,Wen Z Y,et al.Distributions of Fe3+and its influence on microbial products in membrane bioreactor[J].Bulletin of the Chinese Ceramic Society,2016,35(3):784-788.
[14]Zhang H F,Wang Z P,Zhang L H,et al.Impact of sludge cation distribution pattern on its filterability in membrane bioreactor[J].Bioresource Technology,2014,171:16-21.
[15]Tessier A,Campbell P G C,Bisson M.Sequential extraction procedure for the speciation of particulate trace metals[J].Analytical Chemistry,1979,51(7):844-851.
[16]高峰.黄、东海泥质区沉积物部分金属元素赋存形态研究[D].青岛:中国海洋大学,2009.Gao F.Study on the chemical forms of some metallic elements in the sediments of the mud area in the South Yellow and East China Seas[D].Qingdao:Ocean University of China,2009.
[17]宋照亮,刘丛强,彭渤,等.逐级提取(SEE)技术及其在沉积物和土壤元素形态研究中的应用[J].地球与环境,2004,32(2):70-77.Song Z L,Liu C Q,Peng B,et al.Step-by-Step Extraction(SEE)technology and its application in sediment and soil element morphology research[J].Earth and Environment,2004,32(2):70-77.
[18]寇明旭,刘全阳.金属离子对活性污泥微生物影响研究进展[J].山西建筑,2007,33(5):176-177.Kou M X,Liu Q Y.Researching process of the influence of metallic ion on active sludge microbe[J].Shanxi Architeture,2007,33(5):176-177.
[19]Pinojelcic S A,Hong S M,Park J K.Enhanced anaerobic biodegradability and inactivation of fecal coliforms and Salmonella spp.in wastewater sludge by using microwaves[J].Water Environment Research A Research Publication of the Water Environment Federation,2006,78(2):209-216.
[20]陈睿.Fe3+存在下好氧活性污泥处理制浆中段废水的研究[D].青岛:青岛科技大学,2014.Chen R.Study on treatment of mid-stage pulping effluent by aerobic activated sludge in the presence of Fe3+[D].Qingdao:Qingdao University of Science and Technology,2014.
[21]易维洁,曲东,贾蓉.不同淹水时间水稻土微生物群落的Fe(Ⅲ)还原能力及其与脱氢酶活性的关系[J].应用基础与工程科学学报,2012,20(5):768-776.Yi W J,Qu D,Jia R.Relationships between Fe(Ⅲ)reduction and dehyrogenase activity of microbial communities in paddy soil during different flooding periods[J].Journal of Basic Science and Engineering,2012,20(5):768-776.
[22]Zhang Y,Li B,Xu R X,et al.Effects of pressurized aeration on organic degradation efficiency and bacterial community structure of activated sludge treating saline wastewater[J].Bioresource Technology,2016,222:182-189.
[23]Rabi S,Nakhl A G.Impact of calcium on the membrane fouling in membrane bioreactors[J].Journal of Membrane Science,2008,314(1):134-142.
[24]Cornell R M,Schwertmann U.The iron oxides:structure,properties,reactions,occurrence and uses[J].Mineralogical Magazine,1997,61(5):740-741.
[25]Li J,Zhai S Y,Wang Y E,et al.The research of reduction characteristics of Fe(III)dissimilated by different activated sludge[J].Advanced Materials Research,2013,663:1011-1016.
[26]Oikonomidis I,Burrows L J,Carliellmarquent 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.
[27]Hu X,Chen K,Lai X,et al.Effects of Fe(III)on biofilm and its extracellular polymeric substances(EPS)in fixed bed biofilm reactors[J].Water Science&Technology A Journal of the International Association on Water Pollution Research,2016,73(9):2060.
[28]Li H,Wen Y,Cao A,et al.The influence of multivalent cations on the flocculation of activated sludge with different sludge retention times[J].Water Research,2014,55(2):225-232.
[29]Wang Z,Gao M C,Wang Z,et al.Effect of salinity on extracellular polymeric substances of activated sludge from an anoxic-aerobic sequencing batch reactor[J].Chemosphere,2013,93(11):2789-2795.
[30]马旭阳.黄河水体沉积物中铁与磷的形态分布及相关分析[D].呼和浩特:内蒙古师范大学,2015.Ma X Y.Distribution and correlation analysis of phosphorus and iron fractions in sediments of the Yellow River[D].Hohhot:Inner Mongolia Normal University,2015.
[31]隆茜,张经.陆架区沉积物中重金属研究的基本方法及其应用[J].海洋湖沼通报,2002,25(3):25-35.Long Q,Zhang J.The method of heavy metals study in shelf sediments and its application[J].Transaction of Oceanology and Limnology,2002,25(3):25-35.
[32]钱风越.Fe3O4纳米颗粒对厌氧消化产甲烷过程的影响研究[D].哈尔滨:哈尔滨工业大学,2015.Qian F Y.Effect of magnetite nanoparticles on methanogenesis by anaerobic bigestion[D].Harbin:Harbin Institute of Technology,2015.
[33]Wang X,Qian J,Li X,et al.Influences of sludge retention time on the performance of submerged membrane bioreactors with the addition of iron ion[J].Desalination,2012,296(25):24-29.
[34]何志江,张源凯,王洪臣,等.活性污泥絮凝沉降速率计算方法研究[J].环境污染与防治,2015,37(12):35-40.He Z J,Zhang Y K,Wang H C,et al.Study on calculation method of flocculation sedimentation rate of activated sludge[J].Environmental Pollution and Control,2015,37(12):35-40.
[35]兰善红,李慧洁,王传路,等.Fe3+对好氧活性污泥理化特性的影响[J].中国造纸学报,2015,30(4):18-21.Lan S H,Li H J,Wang C L,et al.Effect of Fe3+on physicochemical properties of aerobic activated sludge during domestication by pulping middle-stage effluent[J].Transactions of China Pulp and Paper,2015,30(4):18-21.
[36]Abbasi A,Amiri S.Emulsifying behavior of an exopolysaccharide produced by enterobacter cloacae[J].African Journal of Biotechnology,2008,7(10):1574-1576.