-
作为新型脱氮工艺,anammox因其无需外加碳源和曝气、负荷高等优点而受到广泛关注[1-2]。颗粒污泥沉降性能好、生物活性高、抗冲击负荷强。但anammox菌的生长容易受到温度、pH、底物浓度等外界环境因素干扰,从而导致anammox工艺启动难度较大。Anammox颗粒污泥反应器的快速启动是其工程化应用的重要前提。
群体感应(quorum sensing,QS)是指微生物自发合成并释放信号分子,浓度达阈值后被细胞感知并调控相关基因的表达[3],如生物膜的形成、毒力因子的表达、生物发光[4]等。Anammox菌代谢过程中合成并分泌AHLs信号分子,通过调控相关功能基因的表达、胞外聚合物 (extracellular polymeric substance,EPS) 合成等生理行为,最终影响微生物聚集体形成,即AHLs介导QS以调控EPS含量和组成,从而诱导anammox体系中的污泥颗粒化[5]。
LIU等[6]发现anammox菌释放的信号分子中C6-HSL和C8-HSL浓度最高。C6-HSL可改善颗粒的活性,C8-HSL对颗粒的稳定性和沉降性起着关键作用[7]。ZHANG[8]通过在UASB反应器中添加150 μmol·L−1 C6-HSL,使得anammox颗粒污泥的活性提高了16%,达到了1.08 kg·kg−1·d−1 (以每天每千克悬浮物消耗N的质量计) 。HAN等[9]发现C8-HSL在总氮容积负荷为1.68 kg·m−3·d−1的条件下,促进了紧密结合型EPS的蛋白质 (protein,PN) 分泌,提高了污泥的沉降性。张向晖等[10]向升流式厌氧污泥床 (upflow anaerobic sludge blanket,UASB) 反应器中分别添加C6-HSL和C8-HSL,发现质量浓度为0.5 g·L−1的AHLs会抑制anammox菌群生长,但能提高其脱氮性能,并显著促进hzs A的表达。目前,较多研究集中在C6-HSL或C8-HSL单独投加对anammox工艺脱氮性能等方面的影响。但在实际体系中,C6-HSL和C8-HSL同时存在,因此,本研究选择联合投加C6-HSL和C8-HSL以探究其对anammox颗粒污泥工艺启动的影响。
本研究在UASB反应器中接种污水厂剩余污泥和anammox污泥以启动anammox颗粒污泥系统,再联合投加外源信号分子C6-HSL和C8-HSL,通过定期检测并分析进出水氮的质量浓度、沉降指标、EPS质量浓度、污泥粒径、功能基因相对丰度、AHLs质量浓度等以探究外加AHLs对anammox污泥颗粒化过程的作用及其对anammox菌活性和富集的影响,以期为anammox颗粒污泥工艺的启动提供参考。
外加AHLs对厌氧氨氧化颗粒污泥UASB启动的影响
Effect of AHLs addition on start-up of anammox granular sludge-based UASB reactor
-
摘要: 厌氧氨氧化 (anammox) 颗粒污泥反应器的启动是其工程化应用的重要前提。选用升流式厌氧污泥床反应器 (UASB) ,投加外源信号分子N-酰基高丝氨酸内酯 (AHLs) ,探究其对anammox污泥颗粒化过程的影响,以此考察anammox颗粒污泥工艺启动方式。结果表明,联合投加N-DL-己酰基高丝氨酸内酯 (C6-HSL) 和N-DL-辛酰基高丝氨酸内酯 (C8-HSL) 信号分子组 (R1) 和甲醇对照组 (R2) 中NH4+-N、NO2−-N和TN的去除率分别为87.09%、89.13%、76.83%和82.37%、84.39%、69.49%。R1和R2中粒径>0.45 mm的污泥占比为50.67%和35.05%,R1中污泥颗粒化程度高于R2。胞外聚合物 (EPS) 质量浓度 (以每克可挥发性悬浮物) 分别为138.31、116.95 mg·g−1。Anammox功能基因hzo、hzsB基因拷贝数呈增长趋势,且R1高于R2。Anammox菌属Candidatus Brocadia的相对丰度分别为30.30%、8.90%。这表明联合投加C6-HSL和C8-HSL后可促进EPS分泌及其他信号分子的内源释放,进而刺激了anammox菌的富集,加快了anammox污泥的颗粒化进程。本研究可为anammox颗粒污泥工艺的快速启动提供参考。Abstract: The start-up of anaerobic ammonia oxidation(anammox) granular sludge reactor is an important challenge for its engineering application. In this study, the exogenous signal molecule N-acyl homoserine lactone (AHLs) was added to UASB reactor to explore its influence on the granulation process of anammox sludge and provide a basis for the start-up of anammox granular sludge process. It was found that the removal rates of NH4+-N, NO2−-N and TN in signal molecule group (R1) added with N-DL-hexanoyl homoserine lactone (C6-HSL) and N-DL-octanoyl homoserine lactone (C8-HSL) together were 87.09%, 89.13% and 76.83% respectively, and in methanol control group (R2) were 82.37%, 84.39% and 69.49%. The sludge with particle size > 0.45 mm in R1 accounted for 50.67%, and that in R2 accounted for 35.05%. The granulation degree of sludge in R1 was higher than that in R2. The extracellular polymeric substances (EPS) concentrations of R1 and R2 were 138.31 mg·g−1VSS and 116.95 mg·g−1VSS, respectively. The copy numbers of functional genes hzo and hzsB of anammox showed an increasing trend, and R1 was higher than R2. The relative abundance of anammox genus Candidatus Brocadia was 30.30% and 8.90% respectively. Therefore, the addition of C6-HSL and C8-HSL can promote the accumulation of anammox bacteria and accelerate the granulation process of anammox sludge by promoting the secretion of EPS and the endogenous release of other signal molecules.
-
Key words:
- anaerobic ammonia oxidation /
- granular sludge /
- signal molecule /
- C6-HSL /
- C8-HSL
-
表 1 UASB反应器不同阶段的运行工况
Table 1. Operating conditions of UASB reactor at different stages of startup period
阶段 时间/d 进水TN/ (mg·L−1) HRT/h Ⅰ 12 165 24 Ⅱ 44 165 24 Ⅲ 18 270 24 Ⅳ 18 350 24 表 2 qPCR扩增引物序列及其条件
Table 2. qPCR amplification primer sequence and conditions
目的基因 引物 引物序列 退火温度/ ℃ 碱基数目 参考文献 anammox 16S A438f GTCRGGAGTTADGAAATG 58 250 [15] A648r ACCAGAAGTTCCACTCTC hzsB hzsB364f TGYGCVAGYTGYCAYTAYGARAG 54 301 [16] hzsB640r CTGAAHGGACTYCCBGTRAAYTC nirS nirS-cd3aF GTSAACGTSAAGGARACSGG 59 478 [17] nirS-R3cd GASTTCGGRTGSGTCTTGA hzo hzoclF1 TGTGCATGGTCAATTGAAAG 55 473 [18] hzoclR1 CAACCTCTTCWGCAGGTGCATG ccsB ccsB1189f AYAATCCWGCYGTWMWVGTDGA 57 451 [16] ccsB1589r GCWARRTTRTTRTCDKKATACCA 表 3 不同阶段R1和R2的EPS质量浓度、PN/PS
Table 3. EPS concentration, PN/PS of R1 and R2 at different stages
阶段 EPS/(mg·g−1) PN/PS R1 R2 R1 R2 阶段Ⅰ 79.78 80.97 2.62 2.77 阶段Ⅱ 129.12 104.05 2.14 2.02 阶段Ⅲ 163.99 146.39 2.26 2.09 阶段Ⅳ 184.74 179.68 2.64 2.34 -
[1] MADEIRA C L, ARAÚJO J C D. Inhibition of anammox activity by municipal and industrial wastewater pollutants: A review[J]. Science of The Total Environment, 2021, 799(10): 149449. [2] CAO Y S, VAN LOOSDRECHT M C M, DAIGGER G T. Mainstream partial nitritation-anammox in municipal wastewater treatment: Status, bottlenecks, and further studies[J]. Applied Microbiology and Biotechnology, 2017, 101(4): 1365-1383. doi: 10.1007/s00253-016-8058-7 [3] FENG Z L, GU M Q, SUN Y P, et al. Potential microbial functions and quorum sensing systems in partial nitritation and anammox processes[J]. Water Environment Research, 2021, 93(9): 1562-1575. doi: 10.1002/wer.1538 [4] PAPENFORT K, BASSLER B L. Quorum sensing signal-response systems in Gram-negative bacteria[J]. Nature Reviews Microbiology, 2016, 14(9): 576-588. doi: 10.1038/nrmicro.2016.89 [5] HU H, HE J, LIU J, et al. Role of N-acyl-homoserine lactone (AHL) based quorum sensing on biofilm formation on packing media in wastewater treatment process[J]. Rsc Advances, 2016, 6(14): 11128-11139. doi: 10.1039/C5RA23466B [6] LIU L J, JI M, WANG F, et al. N-acyl-l-homoserine lactones release and microbial community changes in response to operation temperature in an anammox biofilm reactor[J]. Chemosphere, 2020, 262: 127602. [7] 刘长远, 韩蕊, 衣隆强等. 群体感应信号分子AHLs强化厌氧氨氧化过程综述[J/OL]. 环境工程: 1-11[2023-04-11]. http://kns.cnki.net/kcms/detail/11.2097.X.20221219.1615.002.html. [8] ZHANG J, LI J, ZHAO B H, et al. Long-term effects of N-acyl-homoserine lactone-based quorum sensing on the characteristics of ANAMMOX granules in high-loaded reactors[J]. Chemosphere, 2019, 218: 632-642. doi: 10.1016/j.chemosphere.2018.11.170 [9] HAN H, LI J, ZHANG J, et al. Enhancing the treatment performance of partial denitrification/Anammox process at high nitrogen load: Effects of immobilized strain HFQ8C/N; on the sludge characteristics[J]. Bioresource Technology, 2021, 341: 125870. doi: 10.1016/j.biortech.2021.125870 [10] 张向晖, 彭永臻, 贾方旭, 等. 外源自诱导物对厌氧氨氧化的影响[J]. 中国环境科学, 2018, 38(5): 1727-1733. doi: 10.19674/j.cnki.issn1000-6923.2018.0201 [11] 王衫允. 低氨氮浓度厌氧氨氧化工艺强化及颗粒污泥菌群特性研究[D]. 哈尔滨: 哈尔滨工业大学, 2016. [12] LIU L J, XU S H, WANG F, et al. Effect of exogenous N-acyl-homoserine lactones on the anammox process at 15 ℃: Nitrogen removal performance, gene expression and metagenomics analysis[J]. Bioresource Technology, 2021, b,341: 125760. [13] 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. [14] 操沈彬. 基于短程反硝化的厌氧氨氧化脱氮工艺与菌群特性[D]. 哈尔滨: 哈尔滨工业大学, 2018. [15] HUMBERT S, ZOPFI J, TARNAWSKI S E. Abundance of anammox bacteria in different wetland soils[J]. Environment Microbiology Reports, 2012, 4(5): 484-490. doi: 10.1111/j.1758-2229.2012.00347.x [16] SCHMID M C, HOOPER A B, KLOTZ M G, et al. Environmental detection of octahaem cytochrome c hydroxylamine/hydrazine oxidoreductase genes of aerobic and anaerobic ammonium‐oxidizing bacteria[J]. Environment Microbiology, 2008, 10(11): 3140-3149. doi: 10.1111/j.1462-2920.2008.01732.x [17] THROBACK I, ENWALL K A, HALLIN S. Reassessing PCR primers targeting nirS, nirK and nosZ genes for community surveys of denitrifying bacteria with DGGE[J]. FEMS Microbiology Ecology, 2010, 49(3): 401-417. [18] ZHOU Z, CHEN J, MENG H, et al. New PCR primers targeting hydrazine synthase and cytochrome c biogenesis proteins in anammox bacteria[J]. Applied Microbiology Biotechnology, 2017, 101(3): 1-21. [19] 李海玲, 李冬, 张杰, 等. 调控温度和沉降时间实现 ANAMMOX 颗粒快速启动及其稳定运行[J]. 环境科学, 2019, 40(2): 837-844. [20] KREUK M D, KISHIDA N, LOOSDRECHT M V. Aerobic granular sludge–state of the art[J]. Water Science& amp; Technology, 2007, 55(8): 75-81. [21] 范骏洋, 张善林, 邹海晴, 等. 乳品废水厌氧反应器快速启动及颗粒污泥形成[J]. 工业水处理, 2020, 40(11): 66-69. [22] ZHU G B, WANG Y S, MA B, et al. Anammox granular sludge in low-ammonium sewage treatment: Not bigger size driving better performance[J]. Water Research, 2018, 142: 147-158. doi: 10.1016/j.watres.2018.05.048 [23] TANG X, GUO Y Z, CHEN S 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. [24] HOU X L, LIU S T, ZHANG Z T. Role of extracellular polymeric substance in determining the high aggregation ability of anammox sludge[J]. Water Research, 2015, 75: 51-62. doi: 10.1016/j.watres.2015.02.031 [25] LIU Y Q, LIU Y, TAY J H. The effects of extracellular polymeric substances on the formation and stability of biogranules[J]. Applied Microbiology and Biotechnology, 2004, 65(2): 143-148. [26] SHENG G P, YU H Q, LI X Y. Extracellular polymeric substances (EPS) of microbial aggregates in biological wastewater treatment systems: a review[J]. Biotechnology Advances, 2010, 28(6): 882-894. doi: 10.1016/j.biotechadv.2010.08.001 [27] WATERS C M, LU W Y, RABINOWITZ J D, et al. Quorum sensing controls biofilm formation in Vibrio cholerae through modulation of cyclic Di-GMT levels and repression of vpsT[J]. Journal Of Bacteriology, 2008, 190(7): 2527-2536. doi: 10.1128/JB.01756-07 [28] VAN DER STAR W R L, MICLEA A I, VAN DONGEN U G J M, et al. The membrane bioreactor: A novel tool to grow anammox bacteria as free cells[J]. Biotechnology and Bioengineering, 2008, 101(2): 286-294. doi: 10.1002/bit.21891