HRT对UASB厌氧反硝化脱氮的影响
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摘要
在反硝化脱氮的影响因素方面,研究多集中在碳源种类和碳氮比(C/N)2个方面,而对水力停留时间(HRT)的影响很少有报道。采用UASB作为厌氧反硝化反应器,进水NO_3~--N为50 mg·L~(-1),C/N比固定为1.5,分别以葡萄糖和乙酸钠作碳源,研究HRT对反硝化效果的影响。结果表明:当外加碳源为葡萄糖时,最佳HRT为6 h,此时NO_3~--N和TN的去除效果最好,去除率分别为79.5%和63.8%,出水NO_2~--N和NH_4~+-N浓度分别为4.69 mg·L~(-1)和2.22 mg·L~(-1);当外加碳源为乙酸钠时,最佳HRT为4 h,对应的NO_3~--N和TN去除率分别为99.0%和91.4%,出水NO_2~--N和NH_4~+-N浓度分别为3.08 mg·L~(-1)和0.47 mg·L~(-1)。HRT对反硝化效果有显著影响,且跟碳源种类有关。HRT会影响反硝化菌、反硝化异化还原成铵(DNRA)细菌和其他异养菌之间的平衡。
As regards influencing factors of nitrogen removal by denitrification, attentions have been focused on two aspects: carbon source type and carbon/nitrogen ratio(C/N). However, few reports referred to hydraulic retention time(HRT). In present work, effects of HRTs on anaerobic denitrification in UASB reactor were investigated. Nitrate concentration in influent was 50 mg·L~(-1) and the C/N ratio was 1.5. Glucose and sodium acetate were used as the sole carbon source, respectively. The experimental results showed that when the carbon source was glucose, the optimal HRT was 6 h, corresponding removal rates of NO_3~--N and TN were 79.5% and 63.8%, respectively. NO_2~--N and NH_4~+-N concentrations in effluent were 4.69 mg·L~(-1) and 2.22 mg·L~(-1), respectively. When the carbon source was sodium acetate, the optimal HRT was 4 h, corresponding removal rates of NO_3~--N and TN were 99.0% and 91.4%,respectively. NO_2~--N and NH_4~+-N concentrations in effluent were 3.08 mg·L~(-1) and 0.47 mg·L~(-1), respectively. The present study concluded that HRT, combined with carbon source types, had a significant effect on denitrification and HRT affected the balance among denitrifying bacteria, bacteria responsible for dissimilatory reduction of nitrate to ammonium(DNRA) and other heterotrophic bacteria.
As regards influencing factors of nitrogen removal by denitrification, attentions have been focused on two aspects: carbon source type and carbon/nitrogen ratio(C/N). However, few reports referred to hydraulic retention time(HRT). In present work, effects of HRTs on anaerobic denitrification in UASB reactor were investigated. Nitrate concentration in influent was 50 mg·L~(-1) and the C/N ratio was 1.5. Glucose and sodium acetate were used as the sole carbon source, respectively. The experimental results showed that when the carbon source was glucose, the optimal HRT was 6 h, corresponding removal rates of NO_3~--N and TN were 79.5% and 63.8%, respectively. NO_2~--N and NH_4~+-N concentrations in effluent were 4.69 mg·L~(-1) and 2.22 mg·L~(-1), respectively. When the carbon source was sodium acetate, the optimal HRT was 4 h, corresponding removal rates of NO_3~--N and TN were 99.0% and 91.4%,respectively. NO_2~--N and NH_4~+-N concentrations in effluent were 3.08 mg·L~(-1) and 0.47 mg·L~(-1), respectively. The present study concluded that HRT, combined with carbon source types, had a significant effect on denitrification and HRT affected the balance among denitrifying bacteria, bacteria responsible for dissimilatory reduction of nitrate to ammonium(DNRA) and other heterotrophic bacteria.
引文
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[10]殷芳芳,王淑莹,昂雪野,等.碳源类型对低温条件下生物反硝化的影响[J].环境科学,2009,30(1):108-113.
[11]曹相生,钱栋,孟雪征.乙酸钠为碳源时的污水反硝化规律研究[J].中国给水排水,2011,27(21):76-79.
[12]HUANG B,FENG H,WANG M,et al.The effect of C/N ratio on nitrogen removal in a bioelectrochemical system[J].Bioresource Technology,2013,132:91-98.DOI:10.1016/j.biortech.2012.12.192.
[13]HENZE M.Capabilities of biological nitrogen removal processes from wastewater[J].Water Science&Technology,1991,23:669-679.
[14]MATEJU V,CIZINSKA S,KREJEI J,et al.Biological water denitrification:A review[J].Enzyme&Microbial Technology,1992,14(3):170-183.DOI:10.1016/0141-0229(92)90062-S.
[15]郑平,徐向阳,胡宝兰.新型生物脱氮理论与技术[M].北京:科学出版社,2004:55-75.
[16]韦宗敏,黄少斌,蒋然.碳源对微生物硝酸盐异化还原成铵过程的影响[J].工业安全与环保,2012,38(9):4-7.
[17]KRISHNA-MOHAN T V,NANCHARAIAH Y V,VENUGOPALAN V P,et al.Effect of C/N ratio on denitrification of highstrength nitrate wastewater in anoxic granular sludge sequencing batch reactors[J].Ecological Engineering,2016,91:441-448.DOI:10.1016/j.ecoleng.2016.02.033.
[18]苑泉,王海燕,刘凯,等.HRT对城市污水厂尾水反硝化深度脱氮的影响[J].环境科学研究,2015,28(6):987-993
[2]ZHAO Y,ZHANG B,FENG C,et al.Behavior of autotrophic denitrification and heterotrophic denitrification in an intensified biofilm-electrode reactor for nitrate-contaminated drinking water treatment[J].Bioresource Technology,2012,107:159-165.DOI:10.1016/j.biortech.2011.12.118.
[3]AKUNNA J C,BIZEAU C,MOLETTA R.Nitrate and nitrite reduction with anaerobic sludge using various carbon sources:Glucose,glycerol,acetic acid,lactic acid and methanol[J].Water Research,1993,27(8):1303-1312.DOI:10.1016/0043-1354(93)90217-6.
[4]RUIZ G,JEISON D,CHAMY R.Development of denitrifying and methanogenic activities in USB reactors for the treatment of wastewater:Effect of COD/N ratio[J].Process Biochemistry,2006,41(6):1338-1342.DOI:10.1016/j.procbio.2006.01.007.
[5]CHIU Y C,CHUNG M S.Determination of optimal COD/nitrate ratio for biological denitrification[J].International Biodeterioration&Biodegradation,2003,51(1):43-49.DOI:10.1016/S0964-8305(02)00074-4.
[6]彭宏,刘维仪,刘舒心,等.低碳氮比对生物膜-电极反应器反硝化的影响[J].环境工程学报,2015,9(7):3263-3268.
[7]国家环境保护总局.水和废水监测分析方法[M].4版.北京:中国环境科学出版社,2002:53-74.
[8]GUO Y,GUO L,MEI S,et al.Effects of hydraulic retention time(HRT)on denitrification using waste activated sludge thermal hydrolysis liquid and acidogenic liquid as carbon sources[J].Bioresource Technology,2017,224:147-156.DOI:10.1016/j.biortech.2016.11.056.
[9]高廷耀,顾国维,周琪.水污染控制工程:下册[M].4版.北京:高等教育出版社,2015:170.
[10]殷芳芳,王淑莹,昂雪野,等.碳源类型对低温条件下生物反硝化的影响[J].环境科学,2009,30(1):108-113.
[11]曹相生,钱栋,孟雪征.乙酸钠为碳源时的污水反硝化规律研究[J].中国给水排水,2011,27(21):76-79.
[12]HUANG B,FENG H,WANG M,et al.The effect of C/N ratio on nitrogen removal in a bioelectrochemical system[J].Bioresource Technology,2013,132:91-98.DOI:10.1016/j.biortech.2012.12.192.
[13]HENZE M.Capabilities of biological nitrogen removal processes from wastewater[J].Water Science&Technology,1991,23:669-679.
[14]MATEJU V,CIZINSKA S,KREJEI J,et al.Biological water denitrification:A review[J].Enzyme&Microbial Technology,1992,14(3):170-183.DOI:10.1016/0141-0229(92)90062-S.
[15]郑平,徐向阳,胡宝兰.新型生物脱氮理论与技术[M].北京:科学出版社,2004:55-75.
[16]韦宗敏,黄少斌,蒋然.碳源对微生物硝酸盐异化还原成铵过程的影响[J].工业安全与环保,2012,38(9):4-7.
[17]KRISHNA-MOHAN T V,NANCHARAIAH Y V,VENUGOPALAN V P,et al.Effect of C/N ratio on denitrification of highstrength nitrate wastewater in anoxic granular sludge sequencing batch reactors[J].Ecological Engineering,2016,91:441-448.DOI:10.1016/j.ecoleng.2016.02.033.
[18]苑泉,王海燕,刘凯,等.HRT对城市污水厂尾水反硝化深度脱氮的影响[J].环境科学研究,2015,28(6):987-993