热碱解-好氧消化联合工艺处理剩余污泥的效能及抗性基因变化研究
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摘要
通过研究热碱解(TAH)前后污泥理化指标变化,以及不同曝气量(Qb=0.5、2.0 L/min)和不同固体停留时间(SRT=10、20 d)条件下好氧消化(CAD)和热碱解-好氧消化(ta CAD) 2种工艺常规指标和抗性基因(ARGs)的变化,评价了ta CAD工艺处理剩余污泥的效能,并初步分析了其生态风险.结果表明:在pH=11,T=70℃,t=1 h的热碱解条件下,污泥胞内物质被大量释放,热碱解混合物中SCOD、多糖、蛋白质等的质量浓度可达到原污泥的数10倍.当CAD工艺SRT=10 d时,热碱解的挥发性固体(VS)去除率分别提高113.9%(Qb=0.5 L/min)、160.5%(Qb=2.0 L/min),TCOD去除率分别提高234.6%(Qb=0.5 L/min)、83.3%(Qb=2.0 L/min). ta CAD处理后NH4+-N的质量浓度明显低于CAD的情况.热碱解会使得后续CAD反应器中SCOD和TP的质量浓度上升.减小曝气量、延长SRT的CAD过程有利于ARGs的削减,热碱解可导致CAD中ARGs的部分回升.相关性分析和微生物的群落结构分析结果表明:CAD中ARGs的传播途径以基因水平转移(HGT)途径为主.文章在初步分析ta CAD工艺生态风险的同时,也为其后续污泥处置方式的选择提供理论依据.
In order to evaluate the efficiency of the thermal-alkaline pretreatment-conventional aerobic digestion(taCAD) process and its ecological risk,the change of physicochemical characteristics of sludge before and after thermal alkaline hydrolysis(TAH) and the change of conventional indicators and antibiotic resistance genes(ARGs) of conventional aerobic digestion(CAD) and thermal-alkaline hydrolysis-conventional aerobic digestion(ta CAD) under different aeration rates(Qb= 0.5,2.0 L/min) and solids retention time(SRT = 10,20 d) were tested.The results showed that under the conditions of TAH at pH = 11,T = 70 ℃ and T = 1 h,a large amount of intracellular substances were released from sludge cells,and the content of SCOD,polysaccharides and protein in supernatant could reach tens of times the number of raw sludge. When the SRT of CAD was 10 d,TAH could increase the volatile solid(VS) removal rate by 113.9%(Qb= 0.5 L/min),160.5%(Qb= 2.0 L/min) and TCOD removal rate by 234.6%(Qb= 0.5 L/min),83.3%(Qb= 2.0 L/min). TAH could also significantly improve the oxidation capacity of NH4+-N of CAD system,but it would increase the SCOD and TP in the reactor. Reducing the amount of aeration and extending the SRT of CAD were beneficial to the reduction of ARGs,while TAH could lead to the rebound of part of ARGs in CAD. Correlation analysis and microbial community structure analysis showed that the ARGs transmission pathway in CAD system was mainly based on gene horizontal transfer(HGT). This study made a preliminary evaluation of the ecological environment risk of taCAD and provided a theoretical basis for the selection of subsequent sludge disposal methods.
In order to evaluate the efficiency of the thermal-alkaline pretreatment-conventional aerobic digestion(taCAD) process and its ecological risk,the change of physicochemical characteristics of sludge before and after thermal alkaline hydrolysis(TAH) and the change of conventional indicators and antibiotic resistance genes(ARGs) of conventional aerobic digestion(CAD) and thermal-alkaline hydrolysis-conventional aerobic digestion(ta CAD) under different aeration rates(Qb= 0.5,2.0 L/min) and solids retention time(SRT = 10,20 d) were tested.The results showed that under the conditions of TAH at pH = 11,T = 70 ℃ and T = 1 h,a large amount of intracellular substances were released from sludge cells,and the content of SCOD,polysaccharides and protein in supernatant could reach tens of times the number of raw sludge. When the SRT of CAD was 10 d,TAH could increase the volatile solid(VS) removal rate by 113.9%(Qb= 0.5 L/min),160.5%(Qb= 2.0 L/min) and TCOD removal rate by 234.6%(Qb= 0.5 L/min),83.3%(Qb= 2.0 L/min). TAH could also significantly improve the oxidation capacity of NH4+-N of CAD system,but it would increase the SCOD and TP in the reactor. Reducing the amount of aeration and extending the SRT of CAD were beneficial to the reduction of ARGs,while TAH could lead to the rebound of part of ARGs in CAD. Correlation analysis and microbial community structure analysis showed that the ARGs transmission pathway in CAD system was mainly based on gene horizontal transfer(HGT). This study made a preliminary evaluation of the ecological environment risk of taCAD and provided a theoretical basis for the selection of subsequent sludge disposal methods.
引文
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[23] DEVI P,SAROHA A K. Risk analysis of pyrolyzed biochar made from paper mill effluent treatment plant sludge for bioavailability and eco-toxicity of heavy metals[J].Bioresource Technology,2014,162:308-315.
[24] ELJARRAT E,MARSH G,LABANDEIRA A,et al. Effect of sewage sludges contaminated with polybrominated diphenylethers on agricultural soils[J]. Chemosphere,2008,71(6):1079-1086.
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[29] WANG C,ZUO J E,CHEN X J,et al. Microbial community structures in an integrated two-phase anaerobic bioreactor fed by fruit vegetable wastes and wheat straw[J].Jounrnal of Environmental Sciences,2014,26(12):2484-2492.
[30] FILALI-MEKNASSI Y,TYAGI R D,NARASIAH S. Simultaneous sewage sludge digestion and metal leaching:effect of aeration[J]. Process Biochemistry,2000,(36):253-273.
[31] TONG J,LIU J B,ZHENG X,et al. Fate of antibiotic resistance bacteria and genes during enhanced anaerobic digestion of sewage sludge by microwave pretreatment[J]. Bioresource Technology,2016,217,37-43.
[32] GILLINGS M,BOUCHER Y,LABBATE M,et al. The evolution of class 1 integrons and the rise of antibiotic resistance[J]. Journal of Bacteriology. 2008,190:5095-5100.
[33] LIU M,ZHANG Y,YANG M,et al. Abundance and distribution of tetracycline resistance genes and mobile elements in an oxytetracycline production wastewater treatment system[J]. Environmental Science and Technology,2012,46:7551-7557.
[2] LIU S,ZHU N,LI L Y. The one-stage autothermal thermophilic aerobic digestion for sewage sludge treatment:stabilization process and process and mechanism[J].Bioresource Technology,2012,104:266-273.
[3] DING W C,LI D X,ZENG X L,et al. Enhancing excess sludge aerobic digestion with low intensity ultrasound[J].Journal of Central South University of Technology,2006,13(4):408-411.
[4] GULBIN E,OZLEM D,AYSE F. Disintegration of biological sludge:effect of ozone oxidation and ultrasonic treatment on aerobic digestibility[J]. Bioresource Technology,2010,101(21):1-6.
[5] CAI M,LIU H,WEI Y S. Enhanced biohydrogen production from sewage sludge with alkaline pretreatment[J].Environmental Science and Technology,2004,38(11):3195-3202.
[6] DEVLIN D C,ESTEVES S R R,DINSDALE R M,et al.The effect of acid pretreatment on the anaerobic digestion and dewatering of waste activated sludge[J]. Bioresource Technology,2011,102(5):4076-4082.
[7] BOUGRIER C,DELGENES J P,CARRERE H. Effects of thermal treatments on five different waste activated sludge samples solubilisation,physical properties and anaerobic digestion[J]. Chemical Engineering Journal,2008,139(2):236-244.
[8] LI C X,WANG X D,ZHANG G Y,et al. Hydrothermal and alkaline hydrothermal pretreatments plus anaerobic digestion of sewage sludge for dewatering and biogas production:bench-scale research and pilot-scale verification[J]. Water Research,2017,117:49-57.
[9] NEYENS E,BAEYENS J,CREEMERS C. Alkaline thermal sludge hydrolysis[J]. Journal of Hazardous Materials,2003,97(1/2/3):295-314.
[10] VLYSSIDES A G,KARLIS P K. Thermal-alkaline solubilization of waste activated sludge as a pretreatment sludge as a pretreatment evaluation and economic analysis[J]. Bioresource Technology,2014,165(8):183-190.
[11] KIM J,YU Y,LEE C. Thermo-alkaline pretreatment of waste activated sludge at low-temperatures:effects on sludge disintegration,methane production,and methanogen community structure[J]. Bioresource Technology,2013,144(6):194-201.
[12]何轮凯,张敏,刘有胜,等.长期施用粪肥的土壤中抗生素耐药基因的消减规律[J].华南师范大学学报(自然科学版),2018,50(1):1-10.HE L K,ZHANG M,LIU Y S,et al. Dynamics of antibiotic resistance genes in soil chronically fertilized by swine manure[J]. Journal of South China Normal University(Natural Science Edition),2018,50(1):1-10.
[13] PEAK N,KNAPP C W,YANG R K,et al. Abundance of six tetracycline resistance genes in wastewater lagoons at cattle feedlots with different antibiotic use strategies[J].Environment Microbiology,2007,9(1):143-149.
[14]魏晓东,刘叶新,周志洪,等.广州典型排放源废水中抗生素的污染特征和去除效果[J],华南师范大学学报(自然科学版),2018,50(1):11-20.WEI X D,LIU X Y,ZHOU Z H,et al. Occurrence and removal of antibiotics from wastewater of typical emission sources in Guangzhou,China[J]. Journal of South China Normal University(Natural Science Edition),2018,50(1):11-20.
[15] LI D,YANG M,HU J,et al. Determination and fate of oxytetracycline and related compounds in oxytetracycline production wastewater and the receiving river[J]. Environment Toxicology and Chemistry,2008,27:80-86.
[16] DENG Y,ZHANG Y,GAO Y,et al. Microbial community compositional analysis for series reactors treating high level antibiotic wastewater[J]. Environmental Science and Technology,2012,46:795-801.
[17] MA Y,WILSON C A,NOVAK J T,et al. Effect of various sludge digestion conditions on sulfonamide,macrolide,and tetracycline resistance genes and class 1 integrons[J]. Environmental Science and Technology,2011,45(18),7855-7861.
[18] DAVID L D,TIMOTHY M L. Effect of temperature on the rate of genes encoding tetracycline resistance and the integrase of class 1 integrons within anaerobic and aerobic digesters treating municipal wastewater solids[J]. Environmental Science and Technology,2010,44,9128-9133.
[19] LIU M M,DING R,ZHANG Y,et al. Abundance and distribution of macrolide-lincosamide-streptogramin resistance genes in an anaerobic-aerobic system treating spiramycin production wastewater[J]. Water Research,2014,63:33-41.
[20] CHRISTGEN B,YANG Y,AHAMED Z. et al. Metagenomics shows low energy anaerobic-aerobic treatment reactors reduce antibiotic resistance gene dissemination from domestic wastewater[J]. Environmental Science and Technology,2015,49(4):2577-2584.
[21] HYUN M J,LEE J W,KIM Y B,et al. Fate of antibiotic resistance genes and metal resistance genes during thermophilic aerobic digestion of sewage sludge[J]. Bioresource Technology,2018,249,635-643.
[22] DOU X,CHEN D,HU Y,et al. Carbonization of heavy metal impregnated sewage sludge oriented towards potential co-disposal[J]. Journal of Hazardous Materials,2017,321:132-145.
[23] DEVI P,SAROHA A K. Risk analysis of pyrolyzed biochar made from paper mill effluent treatment plant sludge for bioavailability and eco-toxicity of heavy metals[J].Bioresource Technology,2014,162:308-315.
[24] ELJARRAT E,MARSH G,LABANDEIRA A,et al. Effect of sewage sludges contaminated with polybrominated diphenylethers on agricultural soils[J]. Chemosphere,2008,71(6):1079-1086.
[25]韦朝海,张小璇,任源,等.持久性有机物的水污染控制:吸附富集、生物降解与过程分析[J].环境化学,2011,30(1):300-309.WEI C H,ZHANG X X,REN Y,et al. Pollution control of persistent organic pollutants in water system:adsorption/enrichment,biodegradation and process analysis[J].Environmental Chemistry,2011,30(1):300-309.
[26]谢武明.城市污水二级生化处理PCBs的行为研究[D].广州:华南理工大学,2004.XIE W M. Behavior of PCBs in secondary biochemical treatment of municipal wastewater[D]. Guangzhou:South China University of Technology,2004.
[27] PENG S,WANG Y,ZHOU B,et al. Long-term application of fresh and composted manure increase tetracycline resistance in the arable soil of eastern China[J]. Science of the Total Environment,2015,506:279-286.
[28] WALTER W G. Standard methods for examination of water and wastewater[J]. American Journal of Public Health and the Nations Health,1961,51(6):941.
[29] WANG C,ZUO J E,CHEN X J,et al. Microbial community structures in an integrated two-phase anaerobic bioreactor fed by fruit vegetable wastes and wheat straw[J].Jounrnal of Environmental Sciences,2014,26(12):2484-2492.
[30] FILALI-MEKNASSI Y,TYAGI R D,NARASIAH S. Simultaneous sewage sludge digestion and metal leaching:effect of aeration[J]. Process Biochemistry,2000,(36):253-273.
[31] TONG J,LIU J B,ZHENG X,et al. Fate of antibiotic resistance bacteria and genes during enhanced anaerobic digestion of sewage sludge by microwave pretreatment[J]. Bioresource Technology,2016,217,37-43.
[32] GILLINGS M,BOUCHER Y,LABBATE M,et al. The evolution of class 1 integrons and the rise of antibiotic resistance[J]. Journal of Bacteriology. 2008,190:5095-5100.
[33] LIU M,ZHANG Y,YANG M,et al. Abundance and distribution of tetracycline resistance genes and mobile elements in an oxytetracycline production wastewater treatment system[J]. Environmental Science and Technology,2012,46:7551-7557.