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传统生物脱氮技术具有曝气能耗高、碳源消耗量大、污泥产量高,且易产生温室气体CO2等不足[1] 。随着上世纪90年代厌氧氨氧化(anaerobic ammonium oxidation,anammox)作为新的短流程脱氮途径被证实,基于anammox反应的新型生物脱氮技术迅速成为国内外研究热点[2] 。该反应即在缺氧/无氧条件下,以氨为电子供体,亚硝酸盐为电子受体,产生氮气和少量硝酸盐的生物反应。相比于传统脱氮技术,anammox具有节省60%以上曝气量、节约100%碳源、极大降低污泥产量和减排温室气体等优势[3]。
目前,anammox主要用于污泥消化液和高NH4+-N工业水的处理,在世界范围内已有较多应用案例,其技术经济优势已得到证明[4-5] 。除了污泥消化液和工业废水等侧流处理外,近5年来,已有研究者开始将anammox应用于城市污水主流程的研发[6-7] 。亚硝化(partial nitrification,PN)-anammox (PN-A)工艺可实现污水自养生物脱氮,在城市污水主流程中已有较多研究,可分为单级工艺和两级工艺[8] 。但在城市污水低温和低基质条件下,亚硝酸盐氧化菌(nitrite oxidizing bacteria, NOB)生长速率大于氨氧化菌(ammonia oxidizing bacteria, AOB),污水中游离氨和游离的亚硝酸盐无法有效抑制NOB生长繁殖。因此,AOB很难竞争过NOB,这会导致亚硝酸盐积累不足,较难实现长期稳定的anammox反应,故很难维持其在工程应用中的稳定性和高效性[9-10] 。2013年彭永臻院士团队首次提出短程反硝化(partial denitrification,PD)-anammox(PD-A)工艺。该工艺通过部分反硝化实现相对稳定的亚硝酸盐积累。但短程反硝化反应仍需消耗碳源,增加外碳源来实现PD将增加运行成本。为了将进水中的可生物降解碳源充分应用于PD,彭院士团队也采用“厌氧-好氧-缺氧”模式(AOA)实现内碳源短程反硝化-anammox,其原理是聚糖菌(glycogen accumulating organisms,GAOs)和聚磷菌(phosphorus accumulating organisms,PAOs)在厌氧区能将COD贮存为内碳源,进而在缺氧区发生PD而产生NO2−-N[11] 。但内源反硝化反应速率较慢[12] ,会导致缺氧区的体积增大,且PD相对于PN来说,对曝气量及碳源需求更高。
PN-A和PD-A耦合工艺可将NOB和厌氧氨氧化菌(anaerobic ammonium oxidation bacteria, AnAOB)产生的部分NO3−-N还原成NO2−-N继续进行anammox反应,降低对NOB控制的要求,同时也能充分利用亚硝化节约能耗的特点,可为主流程脱氮提供一种高效、低耗的解决方案。目前,基于PN-A和PD-A耦合工艺的多途径脱氮研究报道较少,本研究以实际市政污水为处理对象,在厌氧-好氧-缺氧推流式反应器的缺氧区植入高性能纤维束填料,以在主流程实现PN-A和PD-A等多途径高效脱氮,依据市政污水进水水质变化,通过优化外回流比、曝气量等运行参数进行污染物负荷的合理分配,从而实现主流程anammox耦合多途径稳定高效脱氮,以期为anammox的工艺优化及工程应用提供参考。
主流程厌氧氨氧化耦合多种脱氮途径处理市政污水
Mainstream anammox coupled with multiple denitrification paths to treat municipal wastewater
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摘要: 采用厌氧-好氧-缺氧推流反应器,研究实现低碳氮比主流程厌氧氨氧化(anammox)耦合多种脱氮途径的启动条件,并对脱氮途径进行分析。首先进行短程硝化驯化启动,接着在缺氧池投加填料以及接种厌氧氨氧化细菌(AnAOB),进行主流程anammox工艺脱氮。结果表明,好氧池DO约为1.5 mg·L−1时,NH4+-N去除率为80%,亚硝氮积累率为50%,短程硝化驯化启动成功。AnAOB接种启动后,在维持缺氧池DO为0.3~0.5 mg·L−1,缺氧池NH4+-N去除量为好氧池的3倍时,可实现进水C/N为2,出水总无机氮 (TIN) 低于6 mg·L−1,NH4+-N去除率>95%,这表明anammox驯化启动成功。分析缺氧池氮素变化情况表明缺氧池存在anammox及反硝化多种脱氮途径。高通量测序结果可确定Candidatus Kuenenia和Candidatus Brocadia等AnAOB菌属及Denitratisoma(反硝化菌)在缺氧池中显著存在,从微生物种群角度解析了anammox及反硝化等多种脱氮途径,使出水TIN<6 mg·L−1。该工艺可调控主流程anammox耦合多种脱氮途径,为低C/N市政污水深度脱氮提供可行的技术途径。Abstract: In this study, an anaerobic-aerobic-anoxic push-flow reactor was used to study the start-up conditions for realizing mainstream anaerobic ammonia oxidation (anammox) coupled with multiple denitrification pathways with low C/N and to analyze the denitrification pathways. The experiment started with a partial nitrification domestication, followed by filling of the anoxic tank and inoculation with anaerobic ammonia oxidizing bacteria (AnAOB) to achieve denitrification in mainstream anammox process. The results showed that the removal rate of NH4+-N was 80% and the nitrite accumulation ratio was 50% when the DO was about 1.5 mg·L−1 in the aerobic tank. The partial nitrification domestication was started successfully . After the inoculation of AnAOB, the influent C/N was 2, the effluent total inorganic nitrogen (TIN) was less than 6 mg·L−1 and the NH4+-N removal rate was more than 95% when the DO of the anoxic tank was maintained at 0.3~0.5 mg·L−1 and the NH4+-N removal in the anoxic tank was three times that of the aerobic tank, which showed that anammox domestication was successfully started. Analysis of nitrogen variation in the anoxic tank indicated the presence of anammox and multiple denitrification pathway. High-throughput sequencing results determined that AnAOB bacteria such as Candidatus Kuenenia and Candidatus Brocadia and Denitratisoma (denitrifying bacteria) had significant presence in the anoxic tank, which resolved from the perspective of microbial populations that multiple denitrification pathways such as anammox and denitrification existed and made the effluent TIN less than 6 mg·L−1. This process could regulate the mainstream anammox coupled with multiple denitrification pathways, providing a feasible technical approach for deep denitrification of low C/N municipal wastewater.
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Key words:
- anammox /
- municipal wastewater /
- partial nitrification
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表 1 不同运行阶段实验参数
Table 1. Operating parameters during different experimental periods
阶段 时间/d 好氧池曝气量/(mL·min−1) 缺氧池曝停比 外回流比 I 1~30 0.3 — 100% 31~59 0.7 — 150% II 60~90 0.7~0.4 30 s/(50~30) s 100% III 91~164 0.4~0.3 30 s/30 s 100% -
[1] CHEN Y J, GUO G Z, LI Y Y. A review on upgrading of the anammox-based nitrogen removal processes: Performance, stability, and control strategies[J]. Bioresource Technology, 2022, 364: 127992. doi: 10.1016/j.biortech.2022.127992 [2] ZHANG L, JIANG L, ZHANG J T, et al. Enhancing nitrogen removal through directly integrating anammox into mainstream wastewater treatment: Advantageous, issues and future study[J]. Bioresource Technology, 2022, 362: 127827. doi: 10.1016/j.biortech.2022.127827 [3] CHEN H, WANG H, CHEN R, et al. Unveiling performance stability and its recovery mechanisms of one-stage partial nitritation-anammox process with airlift enhanced micro-granules[J]. Bioresource Technology, 2021, 330: 124961. doi: 10.1016/j.biortech.2021.124961 [4] ZHAO Q, PENG Y, LI J, et al. Sustainable upgrading of biological municipal wastewater treatment based on anammox: From microbial understanding to engineering application[J]. Science of The Total Environment, 2022, 813: 152468. doi: 10.1016/j.scitotenv.2021.152468 [5] LACKNER S, GILBERT E M, VLAEMINCK S E, et al. Full-scale partial nitritation/anammox experiences–an application survey[J]. Water Research, 2014, 55: 292-303. doi: 10.1016/j.watres.2014.02.032 [6] LV Y, PAN J, HUO T, et al. Enhance the treatment of low strength wastewater at low temperature with the coexistence system of AnAOB and heterotrophic bacteria: performance and bacterial community[J]. Science of the Total Environment, 2020, 714: 136799. doi: 10.1016/j.scitotenv.2020.136799 [7] BUNSE P, ORSCHLER L, AGRAWAL S, et al. Membrane aerated biofilm reactors for mainstream partial nitritation/anammox: Experiences using real municipal wastewater[J]. Water Research X, 2020, 9: 100066. doi: 10.1016/j.wroa.2020.100066 [8] 徐峥勇. 基于亚硝化、厌氧氨氧化与反硝化的脱氮耦合工艺及其控制策略研究[D]. 长沙: 湖南大学, 2011. [9] TRINH H P, LEE S H, JEONG G, et al. Recent developments of the mainstream anammox processes: challenges and opportunities[J]. Journal of Environmental Chemical Engineering, 2021, 9(4): 105583. doi: 10.1016/j.jece.2021.105583 [10] GHOLAMI-SHIRI J, AZARI M, DEHGHANI S, et al. A technical review on the adaptability of mainstream partial nitrification and anammox: Substrate management and aeration control in cold weather[J]. Journal of Environmental Chemical Engineering, 2021, 9(6): 106468. doi: 10.1016/j.jece.2021.106468 [11] GAO X J, ZHANG L, PENG Y Z, et al. The successful integration of anammox to enhance the operational stability and nitrogen removal efficiency during municipal wastewater treatment[J]. Chemical Engineering Journal, 2023, 451: 138878. doi: 10.1016/j.cej.2022.138878 [12] GAO X J, ZHANG T, WANG B, et al. Advanced nitrogen removal of low C/N ratio sewage in an anaerobic/aerobic/anoxic process through enhanced post-endogenous denitrification[J]. Chemosphere, 2020, 252: 126624. doi: 10.1016/j.chemosphere.2020.126624 [13] 刘小钗. A2/O短程硝化耦合厌氧氨氧化强化脱氮技术研究[D]. 西安: 西安建筑科技大学, 2020. [14] 姚丽婷, 梁瑜海, 陈漫霞, 等. 高溶解氧条件下不同曝气量对短程硝化性能及微生物特征的影响[J]. 环境科学学报, 2021, 41(8): 3258-3267. doi: 10.13671/j.hjkxxb.2021.0188 [15] 郭凯成, 刘文如, 宋家俊, 等. 短程硝化的影响因素及其耦合工艺的研究进展[J]. 工业水处理, 2022, 42(4): 46-56. [16] 刘文龙. 城市污水主流厌氧氨氧化连续流工艺的脱氮除磷效能研究[D]. 哈尔滨: 哈尔滨工业大学, 2019. [17] ZHANG T, WANG B, LI X Y, et al. Achieving partial nitrification in a continuous post-denitrification reactor treating low C/N sewage[J]. Chemical Engineering Journal, 2018, 335: 330-337. doi: 10.1016/j.cej.2017.09.188 [18] FENG Y, PENG Y Z, WANG B, et al. A continuous plug-flow anaerobic/aerobic/anoxic/aerobic (AOAO) process treating low COD/TIN domestic sewage: Realization of partial nitrification and extremely advanced nitrogen removal[J]. Science of the Total Environment, 2021, 771: 145387. doi: 10.1016/j.scitotenv.2021.145387 [19] GE S J, PENG Y Z, QIU S, et al. Complete nitrogen removal from municipal wastewater via partial nitrification by appropriately alternating anoxic/aerobic conditions in a continuous plug-flow step feed process[J]. Water Research, 2014, 55: 95-105. doi: 10.1016/j.watres.2014.01.058 [20] YANG Y D, ZHANG L, CHENG J, et al. Achieve efficient nitrogen removal from real sewage in a plug-flow integrated fixed-film activated sludge (IFAS) reactor via partial nitritation/anammox pathway[J]. Bioresource technology, 2017, 239: 294-301. doi: 10.1016/j.biortech.2017.05.041 [21] YANG Y D, JIANG Y M, LONG Y N, et al. Insights into the mechanism of the deterioration of mainstream partial nitritation/anammox under low residual ammonium[J]. Journal of Environmental Sciences, 2023, 126: 29-39. doi: 10.1016/j.jes.2022.04.005 [22] MIAO Y Y, ZHANG L, YANG Y D, et al. Start-up of single-stage partial nitrification-anammox process treating low-strength swage and its restoration from nitrate accumulation[J]. Bioresource Technology, 2016, 218: 771-779. doi: 10.1016/j.biortech.2016.06.125 [23] 冯凯. 低C/N污水脱氮固态碳源的研究[D]. 太原: 山西大学, 2020. [24] 王鑫, 穆永杰, 薛晓飞, 等. 不同气源曝气对一段式厌氧氨氧化工艺启动与运行的影响[J]. 环境工程学报, 2021, 15(8): 2778-2788. doi: 10.12030/j.cjee.202103060 [25] 侯朝阳, 贾紫雯, 付静薇, 等. 部分硝化/厌氧氨氧化 (PN/A) 工艺对城市污水厌氧处理单元出水的强化脱氮效果[J]. 环境工程学报, 2022, 16(3): 806-813. [26] ZHU G, WANG 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 [27] ZHANG W K, YU D S, ZHANG J H, et al. Start-up of mainstream anammox process through inoculating nitrification sludge and anammox biofilm: Shift in nitrogen transformation and microorganisms[J]. Bioresource Technology, 2022, 347: 126728. doi: 10.1016/j.biortech.2022.126728 [28] 张树军, 黄剑明, 马淑勍, 等. 连续流分段进水短程反硝化-厌氧氨氧化耦合工艺的反硝化脱氮特性[J]. 环境工程, 2022, 40(11): 13-18. [29] 薛晶晶, 雷振, 王俊, 等. 一段式短程反硝化耦合厌氧氨氧化工艺处理厌氧膜生物反应器出水[J]. 环境工程学报, 2022, 16(3): 788-797.