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当今在污水处理领域中,以能源自给、资源回收为核心的“碳中和”理念逐渐渗透,成为新型污水处理技术的根本要求。厌氧氨氧化工艺(anaerobic ammonium oxidation,anammox,后简写为AMX)作为新型脱氮技术,因其具有能耗低、流程短、污泥产量少等优势已经成为研究热点[1]。部分亚硝化/厌氧氨氧化工艺(partial nitritation/anammox,PN/A)是基于AMX的典型污水脱氮技术,其机理是利用好氧氨氧化菌(AOB)将氨氮部分氧化为亚硝酸盐,而后厌氧氨氧化菌(AnAOB)利用生成的亚硝酸盐和剩余的氨氮生成氮气。AOB和AnAOB的高效协同是PN/A工艺稳定的基本要求。
PN/A工艺已成功应用于城镇污水厂侧流脱氮和高浓度氨氮工业废水处理,但在城镇污水厂主流工艺应用中面临重大挑战,如氨氮浓度较低、废水温度随季节性波动较大,在冬季温度会低至10 ℃ 左右等。有研究[2]表明,AnAOB最佳生长温度为30~40 ℃,温度下降会降低反应器中的AnAOB活性。杨朝晖等[3]研究不同的降温策略对AnAOB活性的影响,发现AnAOB活性与降温幅度之间存在显著负相关关系,即降温幅度越大,AnAOB活性越低。废水温度的波动给PN/A工艺的稳定运行带来挑战,温度冲击对PN/A脱氮性能的影响有待深入研究。
温度下降不仅降低PN/A系统中颗粒污泥活性,还会导致菌群结构以及胞外聚合物(EPS)的变化。温度对微生物活性产生不同程度的影响,导致菌群间的竞争关系变化,易引起原有菌群间的协同关系失衡。有研究表明,经历长期低温培养后,AnAOB的最适温度前移,PN/A颗粒污泥在低温下的脱氮处理效率趋于稳定[4]。LAURENI等[5]通过逐步降低温度适应低温微生物驯化,发现AMX系统可以耐受10~15 ℃ 的温度。但温度冲击对PN/A污泥的脱氮性能以及微生物种群协同的影响尚不清晰。EPS作为微生物的分泌物及颗粒污泥的重要组成部分,在PN/A污泥系统运行过程中环境发生剧烈变化时,其含量和组分就会相应变化[6]。然而,在低温废水处理过程中,PN/A反应器的EPS特性尚未得到充分的研究。近年来群体感应(quorum sensing, QS)作为细菌交流的一种手段受到关注,即利用细菌产生的自诱导信号分子来调控种群密度和生物膜、颗粒污泥的形成。AnAOB的有些生理特性,如SAA、生长速率和EPS分泌都与QS相关[7],进一步了解EPS与QS的相互作用有助于PN/A工艺的实际工程应用。
本研究考察了PN/A颗粒污泥系统在短期温度冲击下的应激效应及恢复能力,系统考察了短期温度冲击以及不同的降温幅度对PN/A颗粒污泥中AOB、AnAOB和NOB活性及菌群间协同效应的影响和脱氮性能恢复的可行性;建立了温度与系统脱氮负荷的变化模型,分析了EPS对温度冲击的响应规律,为PN/A工艺在主流污水处理中的应用及其提高其应对温度波动的脱氮稳定性提供参考。
短期低温冲击对PN/A颗粒污泥脱氮效能及微生物性能的影响
Effect of short-term low-temperature shock on the denitrification efficiency of PN/A granular sludge and its microbial performance
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摘要: 常温部分亚硝化/厌氧氨氧化(partial nitritation/anammox,PN/A)颗粒污泥中不同功能菌群对温度的响应机制不同,在低温条件下易导致脱氮系统失衡。为此,探讨PN/A颗粒污泥系统在温度冲击下的应激效应,包括脱氮性能、微生物活性和EPS对温度冲击的响应,并考察了温度冲击后系统性能恢复的可行性 。结果表明: PN/A颗粒污泥在25~30 ℃时脱氮性能最佳,平均总氮去除率可达到73.48%;低温冲击会抑制PN/A的脱氮性能,温度越低,其对总氮去除率影响越大,12 ℃以下的低温冲击导致平均总氮去除率下降至40.6%,且即使温度回升至30 ℃,平均总氮去除率只能恢复至66.27%。SGompertz模型可有效拟合温度与系统总氮去除负荷以及温度降幅与总氮去除负荷变化的关系,拟合所得可决系数R2均在0.995以上。通过分析温度对微生物活性影响发现,温度对PN/A颗粒污泥中 AOB、AnAOB以及NOB菌群活性影响不同,AnAOB对低温更加敏感。在12 ℃和7 ℃时,总氮比降解速率q(TN) 分别为0.40 mg·(g·h)−1和0.74 mg·(g·h)−1,相对于30 ℃时,q(TN)下降了93.42%和87.83%。在20~30 ℃时,EPS总量和TB、LB、SB组分基本稳定,温度降至 12 ℃以下,EPS总量及各组分均会大幅增加。EEM检测结果表明,低温可刺激TB-EPS分泌更多色氨酸类蛋白质。Abstract: Different functional bacterial groups in normal temperature partial nitritation/anammox (PN/A) granular sludge have different response mechanisms to temperature, which can easily lead to an imbalance of the denitrification system under low temperature conditions. In this study, the stress effects of PN/A granular sludge system under temperature shock were investigated, including the response of denitrification performance, microbial activity and EPS to temperature shock, and the feasibility of system performance recovery after temperature shock was also investigated. The results showed that PN/A granular sludge had the best performed on denitrification at 25~30 °C, with an average total nitrogen removal rate of 73.48%, and low temperature shock could inhibit PN/A denitrification performance, the lower the temperature was, the greater the effect on the total nitrogen removal rate was. The low-temperature shock below 12°C could lead to the decrease of the average TN removal rate to 40.6%, even when the temperature rose back to 30°C, the average TN removal rate only returned to 66.27%. The SGompertz model could effectively fit the relationship between temperature and total nitrogen removal load, as well as the relationship between temperature reduction and total nitrogen removal load varaition, with the determination coefficients R2 above 0.995. The effects of temperature on the activity of AOB, AnAOB and NOB flora in PN/A granular sludge were different, and AnAOB was more sensitive to low temperature. At 12 °C and 7 °C, total nitrogen specific degradation rate (q(TN)) was 0.40 mg·(g·h)−1 and 0.74 mg·(g·h)−1, respectively, which decreased by 93.42% and 93.42% compared with that at 30 °C. The total amount of EPS and TB, LB and SB fractions were essentially stable at 20~30 °C. When the temperature dropped below 12 °C, the total amount of EPS and each EPS fraction increased significantly. According to the EEM analysis, low temperature could stimulate TB-EPS to secrete more tryptophan-like protein substances.
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表 1 各阶段运行工况说明
Table 1. Operating parameters of the reactor at different operational stages
阶段 运行
时间/d进水NH4+-N
浓度/(mg·L−1)温度
/℃容积负荷
/(kg·(m3·d)−1)I 1~30 100 30 1.63 II 31~38 100 25 1.63 39~69 30 III 70~77 100 20 1.63 78~108 30 IV 109~116 100 12 1.63 117~147 30 V 148~155 100 7 1.63 156~186 30 -
[1] GONG X, WANG B, QIAO X, et al. Performance of the anammox process treating low-strength municipal wastewater under low temperatures: Effect of undulating seasonal temperature variation[J]. Bioresource Technology, 2020, 312: 123590. doi: 10.1016/j.biortech.2020.123590 [2] ISAKA K, DATE Y, KIMURA Y, et al. Nitrogen removal performance using anaerobic ammonium oxidation at low temperatures[J]. FEMS Microbiology Letters, 2008, 282(1): 32-38. doi: 10.1111/j.1574-6968.2008.01095.x [3] 杨朝晖, 徐峥勇, 曾光明, 等. 不同低温驯化策略下的厌氧氨氧化活性[J]. 中国环境科学, 2007, 27(3): 300-305. doi: 10.3321/j.issn:1000-6923.2007.03.003 [4] 刘雨馨, 王建芳, 钱飞跃, 等. 低温下全自养脱氮颗粒污泥适应低基质效能[J]. 环境科学, 2020, 41(9): 4161-4168. doi: 10.13227/j.hjkx.202003036 [5] LAURENI M, FALAS P, ROBIN O, et al. Mainstream partial nitritation and anammox: Long-term process stability and effluent quality at low temperatures[J]. Water Research, 2016, 101: 628-639. doi: 10.1016/j.watres.2016.05.005 [6] TENG Z, SHAO W, ZHANG K, et al. Pb biosorption by leclercia adecarboxylata: Protective and immobilized mechanisms of extracellular polymeric substances[J]. Chemical Engineering Journal, 2019, 375: 122113-122113. doi: 10.1016/j.cej.2019.122113 [7] ZHANG Q, FAN N S, FU J J, et al. Role and application of quorum sensing in anaerobic ammonium oxidation (anammox) process: A review[J]. Critical Reviews in Environmental Science and Technology, 2021, 51(6): 626-648. doi: 10.1080/10643389.2020.1738166 [8] 陈希, 钱飞跃, 王建芳, 等. 环境因子对全自养脱氮颗粒污泥功能菌协同效应的影响[J]. 环境科学, 2018, 39(4): 1756-1762. doi: 10.13227/j.hjkx.201708251 [9] GU C, GAO P, YANG F, et al. Characterization of extracellular polymeric substances in biofilms under long-term exposure to ciprofloxacin antibiotic using fluorescence excitation-emission matrix and parallel factor analysis[J]. Environmental Science & Pollution Research, 2017, 24(15): 13536-13545. [10] MIAO L, WANG S, CAO T, et al. Advanced nitrogen removal from landfill leachate via anammox system based on sequencing biofilm batch reactor (SBBR): Effective protection of biofilm[J]. Bioresource Technology, 2016, 220: 8-16. doi: 10.1016/j.biortech.2016.06.131 [11] 李金璞, 张雯雯, 杨新萍. 活性污泥污水处理系统中胞外多聚物的作用及提取方法[J]. 生态学杂志, 2018, 37(9): 2825-2833. doi: 10.13292/j.1000-4890.201809.001 [12] ADAV S S, LEE D J. Extraction of extracellular polymeric substances from aerobic granule with compact interior structure[J]. Journal of Hazardous Materials, 2008, 154(1/2/3): 1120-1126. doi: 10.1016/j.jhazmat.2007.11.058 [13] 杨振琳, 于德爽, 李津, 等. 海藻糖强化厌氧氨氧化耦合反硝化工艺处理高盐废水的脱氮除碳效能[J]. 环境科学, 2018, 39(10): 4612-4620. doi: 10.13227/j.hjkx.201803218 [14] MENG Y, ZHOU Z, MENG F. Impacts of diel temperature variations on nitrogen removal and metacommunity of anammox biofilm reactors[J]. Water Research, 2019, 160(SEP.1): 1-9. [15] HU Z, LOTTI T, DE KREUK M, et al. Nitrogen removal by a nitritation-anammox bioreactor at low temperature[J]. Applied and Environmental Microbiology, 2013, 79(8): 2807-2812. doi: 10.1128/AEM.03987-12 [16] PARK G, TAKEKAWA M, SODA S, et al. Temperature dependence of nitrogen removal activity by anammox bacteria enriched at low temperatures[J]. Journal of Bioscience and Bioengineering, 2017, 123(4): 505-511. doi: 10.1016/j.jbiosc.2016.11.009 [17] REINO C, SUÁREZ-OJEDA M E, PÉREZ J, et al. Kinetic and microbiological characterization of aerobic granules performing partial nitritation of a low-strength wastewater at 10 ℃[J]. Water Research, 2016, 101: 147-156. doi: 10.1016/j.watres.2016.05.059 [18] ZHOU H, LI X, XU G, et al. Overview of strategies for enhanced treatment of municipal/domestic wastewater at low temperature[J]. Science of the Total Environment, 2018, 643: 225-237. doi: 10.1016/j.scitotenv.2018.06.100 [19] LOTTI T, KLEEREBEZEM R, VAN LOOSDRECHT M C M. Effect of temperature change on anammox activity[J]. Biotechnology & Bioengineering, 2015, 112(1): 98-103. [20] VÁZQUEZ-PADÍN J R, FERNANDEZ I, MORALES N, et al. Autotrophic nitrogen removal at low temperature[J]. Water Science and Technology, 2011, 63(6): 1282-1288. doi: 10.2166/wst.2011.370 [21] JEONG D, LIM H, KIM W. Low-ammonia wastewater treatment by integration of partial nitritation and anaerobic ammonium oxidation (anammox) at 20℃[J]. Journal of Environmental Chemical Engineering, 2021, 9(2): 105122. doi: 10.1016/j.jece.2021.105122 [22] ZHANG L, OKABE S. Ecological niche differentiation among anammox bacteria[J]. Water Research, 2020, 171: 115468. doi: 10.1016/j.watres.2020.115468 [23] LOTTI T, KLEEREBEZEM R, VAN ERP TAALMAN KIP C, et al. Anammox growth on pretreated municipal wastewater[J]. Environmental Science & Technology, 2014, 48(14): 7874-7880. [24] SOLER-JOFRA A, WANG R, KLEEREBEZEM R, et al. Stratification of nitrifier guilds in granular sludge in relation to nitritation[J]. Water Research, 2019, 148: 479-491. doi: 10.1016/j.watres.2018.10.064 [25] YANG Q, PENG Y, LIU X, et al. Nitrogen removal via nitrite from municipal wastewater at low temperatures using real-time control to optimize nitrifying communities[J]. Environmental Science & Technology, 2007, 41(23): 8159-8164. [26] 宋成康, 王亚宜, 韩海成, 等. 温度降低对厌氧氨氧化脱氮效能及污泥胞外聚合物的影响[J]. 中国环境科学, 2016, 36(7): 2006-2013. doi: 10.3969/j.issn.1000-6923.2016.07.015 [27] KAWAGOSHI Y, FUJISAKI K, TOMOSHIGE Y, et al. Temperature effect on nitrogen removal performance and bacterial community in culture of marine anammox bacteria derived from sea-based waste disposal site[J]. Journal of Bioscience and Bioengineering, 2012, 113(4): 515-520. doi: 10.1016/j.jbiosc.2011.11.024 [28] 丁爽. 厌氧氨氧化关键技术及其机理的研究[D]. 杭州: 浙江大学, 2014. [29] KUMAR M, LIN J G. Co-existence of anammox and denitrification for simultaneous nitrogen and carbon removal: Strategies and issues[J]. Journal of Hazardous Materials, 2010, 178(1-3): 1-9. doi: 10.1016/j.jhazmat.2010.01.077 [30] WILÉN B M, LUMLEY D, MATTSSON A, et al. Relationship between floc composition and flocculation and settling properties studied at a full scale activated sludge plant[J]. Water Research, 2008, 42(16): 4404-4418. doi: 10.1016/j.watres.2008.07.033 [31] 郑贝贝. 耐冷菌Bacillus cereus MYB41-22群体感应系统与其温度适应性相关功能研究[D]. 昆明: 昆明理工大学, 2018. [32] 霍唐燃, 潘珏君, 刘思彤. 基于代谢组的厌氧氨氧化菌群对温度的响应机制[J]. 微生物学通报, 2019, 46(8): 1936-1945. doi: 10.13344/j.microbiol.china.190322 [33] TANG X, GUO Y, WU S, et al. Metabolomics uncovers the regulatory pathway of acyl-homoserine lactones based quorum sensing in anammox consortia[J]. Environmental Science & Technology, 2018, 52(4): 2206-2216. [34] ZHAO R, ZHANG H, ZHANG F, et al. Fast start-up anammox process using acyl-homoserine lactones (AHLs) containing supernatant[J]. Journal of Environmental Sciences, 2018, 65: 127-132. doi: 10.1016/j.jes.2017.03.025 [35] ZHU L, ZHOU J, LV M, et al. Specific component comparison of extracellular polymeric substances (EPS) in flocs and granular sludge using EEM and SDS-PAGE[J]. Chemosphere, 2015, 121: 26-32. doi: 10.1016/j.chemosphere.2014.10.053