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截至2020年,我国已建成城镇污水处理厂9 000余座,日处理能力达2.3×108 m3。污水处理过程会伴随大量恶臭气体产生[1],这不仅会危害厂区工作人员和周边居民身体健康[2],还会污染周围环境。因此,污水处理厂恶臭气体治理已受到高度关注。
污水处理厂排放的恶臭气体主要有氨(NH3)和6种挥发性硫化物(volatile sulfur compounds,VSCs,包括硫化氢(H2S)、甲硫醇(MT)、甲硫醚(DMS)、二甲二硫醚(DMDS)、二硫化碳(CS2)和羰基硫(COS))[3-5]。污水处理厂应先收集再处理以上恶臭气体。目前,常见的恶臭处理技术有:物理法、化学法和生物法[6]。物理法包括掩蔽法、稀释扩散法和活性炭吸附法;化学法包括燃烧法、化学氧化法和化学洗涤法;生物法包括生物滤池法、生物滴滤法和生物洗涤法。在污水处理厂除臭工艺中,通常采用多种技术联合除臭[7]。天津咸阳路污水处理厂采用“生物滴滤+活性炭吸附”工艺处理污水泵站排放的NH3和H2S,其去除率高达98%[8]。上海天山污水处理厂采用“化学洗涤+生物滤池”处理污泥脱水机房排放的高浓度恶臭气体,处理后可达到《城镇污水处理厂污染物排放标准》二级标准[9]。广州猎德污水处理厂采用“洗涤+生物滤床”处理污泥处理段产生的NH3和H2S,其去除率均在90%以上[10]。杭州七格污水处理厂采用“生物滴滤+活性炭吸附+生物滴滤”多级处理工艺处理预处理和污泥处理段产生的恶臭气体,处理后可达到《城镇污水处理厂污染物排放标准》二级标准[11]。
目前,污水处理厂的除臭工艺尚存在以下问题:1)当前除臭目标多集中在NH3和H2S,而《恶臭污染物排放标准》(GB 14554-93)规定的8种恶臭物质中有5种VSCs,且嗅阈值远低于NH3和H2S[12],故对标准中规定的其他VSCs关注度不够;2)各构筑物排放的恶臭气体组成和浓度不同,而除臭设施大多为集中收集处理,并未针对不同构筑物而选择不同的处理工艺,忽略了恶臭物质种类和浓度的差异性。
本研究对北京市某污水处理厂(A2/O工艺)恶臭气体处理工艺除臭效果进行监测,通过分析比较4种除臭工艺对NH3和VSCs的去除效果,评估不同处理工艺处理不同构筑物排放的恶臭气体的适用性,以期为污水处理厂恶臭气体的有效处理提供参考。
某A2/O工艺污水处理厂恶臭气体处理设施性能评估
Performance evaluation of odor gas treatment facilities in A2/O wastewater treatment plant
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摘要: 污水处理厂运行中会产生大量恶臭气体,其不同构筑物中排放气体的组成和浓度不尽相同。采用不同工艺(生物法、水洗-生物法、酸洗-生物法和生物-碱洗法)对北京市某污水处理厂产生的恶臭气体进行了处理,并在1 a内开展了共计12次现场监测,以评估除臭设施对氨(NH3)和挥发性硫化物(VSCs,包括硫化氢(H2S)、甲硫醇(MT)、甲硫醚(DMS)、二甲二硫醚(DMDS)、二硫化碳(CS2)和羰基硫(COS))的处理效果。结果表明:污水预处理段、A2/O生物池、二沉池和污泥脱水机房的主要恶臭物质为NH3和H2S;NH3平均质量浓度依次为0.250、0.442、0.151和0.469 mg·m−3,H2S平均质量浓度依次为0.171、0.071、0.033和0.041 mg·m−3;污泥接收间和污泥热水解系统的主要恶臭物质为NH3、H2S、DMS和DMDS;污泥接收间各类恶臭物质的平均质量浓度依次为0.494、0.134、0.034和0.047 mg·m−3,污泥热水解系统中的各类恶臭物质的平均质量浓度依次为4.649、0.188、0.086和0.056 mg·m−3;污泥上清液厌氧氨氧化池的主要恶臭物质为NH3,平均质量浓度为2.315 mg·m−3。污水预处理段、A2/O生物池和污泥脱水机房采用水洗+生物法工艺,其对NH3和H2S的去除率最高可达94%和92%;二沉池除臭工艺为生物法,其对NH3和H2S的去除率为78%和67%;污泥接收间和污泥热水解系统采用生物+碱洗法,其对H2S、MT、DMS、DMDS和CS2的去除率最高分别为96%、89%、80%、84%和81%;污泥上清液厌氧氨氧化池除臭工艺为酸洗+生物法,其对NH3的去除率高达95%。该污水处理厂各工艺段产生的恶臭气体经处理后可同时满足《恶臭污染物排放标准》(GB 14554征求意见稿)和《北京市大气污染物综合排放标准》(DB11/501-2017)。本研究可为采用类似工艺的污水处理厂解决恶臭气体问题提供参考。Abstract: During the operation of wastewater treatment plant (WWTP), a large amount of odor gas will be produced. The odor gas produced by a WWTP in Beijing is treated by different treatment processes (biological method, water washing-biological method, acid pickling-biological method and biological-alkali washing method), and a total of 12 on-site monitoring was carried out within 1 year to evaluate the effect of deodorization facilities on ammonia (NH3) and volatile sulfide compounds (VSCs, including hydrogen sulfide (H2S), methyl mercaptan (MT), methyl sulfide (DMS), dimethyl disulfide (DMDS), carbon disulfide (CS2) and carbonyl sulfur (COS)).The results show that the main odorous substances in wastewater pretreatment section, A2/O biological tank, secondary sedimentation tank and sludge dewatering room are NH3 and H2S; The average mass concentration of NH3 is 0.250, 0.442, 0.151 and 0.469 mg·m−3; and the average mass concentration of H2S is 0.171, 0.071, 0.033 and 0.041 mg·m−3. The main odorous substances in sludge receiving room and sludge thermal hydrolysis system are NH3, H2S, DMS and DMDS; The average mass concentration of odor gas in sludge receiving room is 0.494, 0.134, 0.034 and 0.047 mg·m−3, and the average mass concentration of odor gas in sludge thermal hydrolysis system is 4.649, 0.188, 0.086 and 0.056 mg·m−3. The main odorous substance in the anammox tank is NH3, with an average mass concentration of 2.315 mg·m−3. The deodorization process of wastewater pretreatment section, A2/O biological tank and sludge dewatering room is water washing-biological method, and the maximum removal efficiencies of NH3 and H2S are 94% and 92% respectively. The deodorization process of secondary sedimentation tank is biological method, and the removal efficiencies of NH3 and H2S are 78% and 67% respectively. The deodorization process of sludge receiving room and sludge thermal hydrolysis system is biological-alkali washing method, and the maximum removal efficiencies of H2S, MT, DMS, DMDS and CS2 are 96%, 89%, 80%, 84% and 81% respectively. The deodorization process of anammox tank is acid pickling-biological method, and the removal efficiency of NH3 is as high as 95%. After treatment, the odor gas generated in each process section of the WWTP can meet both the Emission Standard for Malodorous Pollutants (GB 14554 draft) and the Comprehensive Emission Standard of Air Pollutants (DB11/501-2017). This study can provide a reference for WWTP using similar processes to solve the problem of odor gas.
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表 1 污水处理厂各构筑物的除臭工艺
Table 1. Summary of deodorization process in WWTP
构筑物 除臭工艺 处理气量/(m3·h−1) 停留时间/s 化学药剂 生物段 洗涤段 预处理段 水洗+生物滴滤 53 000 20 5 无 A2/O生物池 水洗+生物滴滤 26 000 10 2 无 二沉池 生物滴滤 10 000 12 0 无 污泥接收间 生物滴滤+碱洗 56 000 15 4 NaOH + NaClO 污泥脱水机房 水洗+生物滴滤 13 000 20 3 无 污泥热水解系统 生物滴滤+碱洗 32 000 20 3 NaOH + NaClO 污泥上清液厌氧氨氧化池 酸洗+生物滴滤 28 000 20 3 H2SO4 表 2 VSCs的保留时间和检出限
Table 2. Retention time and detection limit of VSCs
检测物质 保留时间/min 检出限/(μg·m-3) COS 4.649 0.08 MT 6.791 0.20 DMS 11.712 0.17 CS2 12.604 0.10 DMDS 18.575 0.08 表 3 恶臭气体处理效果评价标准
Table 3. Evaluation standard for treatment effect of odor gas
序号 监测项目 排气筒高度 最高允许排放速率/( kg·h−1) DB11/501-2017 GB 14554(征求意见稿) 评价标准 1 NH3 15 m 0.72 0.60 0.60 2 H2S 15 m 0.036 0.06 0.036 3 MT 15 m 0.025 0.006 0.006 4 DMS 15 m 0.25 0.06 0.06 5 DMDS 15 m 0.22 0.15 0.15 6 CS2 15 m 0.14 1.5 0.14 -
[1] 杜亚峰, 李军, 赵珊, 等. 污水处理厂恶臭气体分布规律及挥发性气体定量评价[J]. 净水技术, 2018, 37(7): 69-74. [2] AATAMILA M, VERKASALO P K, KORHONEN M J, et al. Odour annoyance and physical symptoms among residents living near waste treatment centres[J]. Environmental Research, 2011, 111(1): 164-170. doi: 10.1016/j.envres.2010.11.008 [3] LI R, HAN Z, SHEN H, ET al. Volatile sulfur compound emissions and health risk assessment from an A2/O wastewater treatment plant[J]. Science of the Total Environment, 2021, 794: 148741. doi: 10.1016/j.scitotenv.2021.148741 [4] LI R, HAN Z, SHEN H, et al. Emission characteristics of odorous volatile sulfur compound from a full-scale sequencing batch reactor wastewater treatment plant[J]. Science of the Total Environment, 2021, 776: 145991. doi: 10.1016/j.scitotenv.2021.145991 [5] LIU Z. Urban sewage treatment odor gas release characteristics and regional differences[J]. Environmental Technology & Innovation, 2021, 21: 101190. doi: 10.1016/j.eti.2020.101190 [6] 郑斯宇, 杨延梅. 污水处理厂恶臭气体控制综述[J]. 给水排水, 2015, 51(S1): 109-114. [7] 邹博源, 陈广. 城镇污水处理厂臭气污染与除臭技术研究进展[J]. 净水技术, 2020, 39(5): 109-115. [8] 王令凡, 蒋国津. 生物滴滤床技术用于市政污水泵站除臭[J]. 中国给水排水, 2009, 25(20): 73-76. doi: 10.3321/j.issn:1000-4602.2009.20.020 [9] 刘晓兰, 康磊, 卢义程. 生物滤池加离子换风除臭技术在污水处理厂的应用[J]. 中国市政工程, 2013, 38(3): 45-47. doi: 10.3969/j.issn.1004-4655.2013.03.015 [10] 李亮, 赵忠富, 张明杰, 等. 猎德污水处理厂污泥系统除臭工程设计[J]. 给水排水, 2007, 44(12): 40-43. doi: 10.3969/j.issn.1002-8471.2007.12.009 [11] 张丽丽, 郭红峰, 严国奇, 等. 七格污水厂三期工程生物除臭系统的运行效果[J]. 中国给水排水, 2020, 36(1): 69-73. [12] 王亘, 翟增秀, 耿静, 等. 40种典型恶臭物质嗅阈值测定[J]. 安全与环境学报, 2015, 15(6): 348-351. [13] 崔连喜, 关玉春, 王艳丽. 苏玛罐采样-气相色谱-质谱法测定环境空气中99种挥发性有机物[J]. 广州化工, 2020, 48(3): 95-102. doi: 10.3969/j.issn.1001-9677.2020.03.035 [14] 沈秀娥, 常淼, 刘保献, 赵红帅, 王小菊. 大气预浓缩仪-GC/FPD测定环境空气中的痕量硫化物[J]. 中国环境监测, 2015, 31(6): 103-108. doi: 10.3969/j.issn.1002-6002.2015.06.022 [15] 马慧. 吸附法脱除低浓度羰基硫的研究[D]. 大连: 大连理工大学, 2011. [16] RATNASAMY C, WAGNER J P, SPIVEY S, et al. Removal of sulfur compounds from natural gas for fuel cell applications using a sequential bed system[J]. Catalysis Today, 2012, 198(1): 233-238. doi: 10.1016/j.cattod.2012.04.069 [17] HIGGINS M J, CHEN Y C, YAROSZ D P, et al. Cycling of volatile organic sulfur compounds in anaerobically digested biosolids and its implications for odors[J]. Water Environment Research, 2006, 78(3): 243-252. doi: 10.2175/106143005X90065 [18] CHENG X, PETERKIN E, BURLINGAME G A. A study on volatile organic sulfide causes of odors at Philadelphia's Northeast Water Pollution Control Plant[J]. Water Research, 2005, 39(16): 3781-3790. doi: 10.1016/j.watres.2005.07.009 [19] 陈思思, 杨殿海, 庞维海, 等. 污泥中蛋白类物质厌氧转化影响因素及其促进策略研究进展[J]. 化工进展, 2020, 39(5): 1992-1999. [20] 肖本益, 阎鸿, 魏源送. 污泥热处理及其强化污泥厌氧消化的研究进展[J]. 环境科学学报, 2009, 29(4): 673-682. doi: 10.3321/j.issn:0253-2468.2009.04.001