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受控生态生保系统(controlled ecological life support system,CELSS)依据地球生态圈循环原理构建,在密闭空间实现食物、氧气和水等全部生保物资的持续再生供应,是目前公认的解决长期载人深空探测任务过程中人生命保障问题的有效途径[1-3]。CELSS系统中生活废水污染强度大,尿液和各类洗涤剂的浓度高,氨氮浓度高,碳氮比(C/N)低,如何高效低耗的完成生活废水的净化处理是系统水循环的重点和难点[4]。而通过微生物硝化反应将高含量的氮素转化成植物易于直接吸收利用的硝酸盐氮,是实现废水中氮素等矿物质营养元素的循环的有效途径[5-6]。微生物硝化反应是将氮素转化为硝酸盐氮的有效途径,pH会影响氨氧化菌(ammonia oxidizing bacteria,AOB)和亚硝酸盐氧化菌(nitrite-oxidizing bacteria,NOB)的生长和代谢,是生物硝化反应器效能的关键影响因素[7-9]。前期研究表明生物处理工艺能完成尿液废水、高强度生活废水的转化处理,并初步探究了pH对氮素转化性能的影响[10-11]。而针对CELSS系统中特征性生活废水的全程硝化工艺研究相对较少,尤其在pH对于硝化过程中碱度消耗的影响与减量化措施方面缺少系统性的研究。为了优化工艺运行条件和物质消耗,本研究在课题组前期构建BF-MBR(biofilm-membrane bioreactor)工艺的基础上,设计不同pH水平的长期硝化实验和短期硝化实验,考察好氧系统硝化性能与动力学,并评估硝化过程碱度的消耗情况,为CELSS系统中BF-MBR工艺运行参数选择提供依据,以求最大限度降低物质消耗的同时实现氮素的资源化处理。
pH对BF-MBR工艺处理高强度生活废水的影响
Effect of pH on the treatment of high strength domestic wastewater by BF-MBR process
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摘要: 受控生态生保系统中生活废水污染强度大,生物转化后回用于植物培养是废水资源化的有效途径,但面临氮素稳定转化难、碱度消耗较大的问题。以BF-MBR工艺(生物膜耦合膜生物工艺,biofilm-membrane bioreactor)为研究对象,研究了不同pH条件下的好氧硝化性能及硝化动力学,并考察了硝化过程的碱度消耗情况。结果表明,在pH=6.0~7.2内,好氧生物反应器均能获得良好的氨氧化效果,而在pH=6.0~6.5的条件下更有利于全程硝化的维持;氨氧化速率随pH的增加而增大,而亚硝氧化速率在pH 6.6时达到最高;酸性条件下的碱度消耗量远低于碱性条件,而氢氧化钾作为碱液时的消耗量比碳酸氢钾低3.28 g·g-1。从物料损耗和工艺处理效果综合考虑,硝化系统中最佳的pH可调控在6.4~6.5,此时全程硝化率可达97.8%。以上研究结果可为受控生态生保系统中生活废水处理系统的设计和运行提供参考。Abstract: The pollution of domestic wastewater in the controlled ecological life support system (CELSS) is serious. The reuse for plant culture after biological transformation of this domestic wastewater is considered an effective way to resource utilization. However, there are still challenges such as the stability of nitrogen transformation and high alkalinity consumption in the process. In the present study, the biofilm-membrane bioreactor (BF-MBR) process was used to investigate the performance of aerobic nitrification and nitrification kinetics under different pH conditions, and the alkalinity consumption in the nitrification process. The results demonstrated that the aerobic bioreactor had a good ammonia oxidation capability in the range of pH=6.0~7.2, and pH=6.0~6.5 was more conducive to the maintenance of full nitrification. The rate of ammonia oxidation rose as pH increased, while the rate of nitrite oxidation reached its maximum at pH=6.6. The consumption of alkalinity under acidic conditions was much lower than that under alkaline conditions, and the consumption of KOH as alkali liquor was 3.28 g·g-1 lower than that of KHCO3. The optimal pH for the aerobic nitrification system could be adjusted to the range of 6.4~6.5 based on the comprehensive analysis of material consumption and treatment effect by the process, then the full nitrification rate could reach 97.8%. The findings of the study can provide a reference for the design and operation of domestic wastewater treatment system in CELSS.
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表 1 1/5尿液强度生活废水配方用量
Table 1. The composition of domestic wastewater with 1/5 urine concentration
项目 品牌 配水用量 牙膏 冷酸灵 2 cm 洗发水 飘柔长效清爽去屑 2 mL 沐浴露 舒肤佳 2 mL 洗衣液 蓝月亮深层洁净护理 2 mL 洗面奶 曼秀雷敦控油抗痘洁面乳(男士) 2 mL 洗手液 蓝月亮抑菌洗手液 3 mL 新鲜尿液 新鲜采集 4 L 自来水 约16 L 注:生活废水每次配水总量为20 L。 表 2 废水进水水质表
Table 2. The water quality of influent wastewater
阶段 时间段/d TOC/(mg·L−1) TN/(mg·L−1) NH4+-N/(mg·L−1) C/N 启动期 1~8 744±10 815±150 490±200 0.94 pH=6.4~6.5 9~16 831±15 865±50 519±300 0.96 pH=7.1~7.2 17~25 892±50 875±50 524±400 0.95 过渡期 26~28 831±15 865±50 519±300 0.96 pH=6.0~6.1 29~38 954±10 1089±50 714±200 0.88 表 3 不同pH体系中氨氧化过程中动力学参数值
Table 3. Kinetic parameter values of ammonia oxidation process in different pHs
pH 拟合度R12 μmax/(mg·(L·d)−1) K1/(mg·L−1) U1/(g·(g·d)−1) U2/(g·(g·d)−1) Umax/d−1 6.1±0.1 0.965 2.58 29.22 0.0013 0.108 0.011 6.6±0.1 0.982 17.15 7.57 0.0086 0.714 0.071 7.2±0.1 0.968 41.82 1.27 0.0209 1.743 0.174 7.9±0.1 0.966 57.47 0.16 0.0287 2.395 0.239 表 4 不同pH体系中亚硝酸盐氧化过程中动力学参数值
Table 4. Kinetic parameter values of nitrite oxidation process in different pHs
pH 拟合度R22 vmax/(mg·(L·d)−1) K2/(mg·L−1) V1/(g·(g·d)−1) V2/(g·(g·d)−1) Vmax/d−1 6.1±0.1 0.966 23.41 123.20 0.0117 1.672 0.167 6.6±0.1 0.958 116.01 231.20 0.0580 8.286 0.829 7.2±0.1 0.962 35.46 53.31 0.0177 2.533 0.253 7.9±0.1 0.982 33.70 14.57 0.0169 2.407 0.241 表 5 好氧反应器中不同pH下的耗碱量
Table 5. Alkali consumption in aBF-MBR at different pHs
pH KHCO3消耗量/(g·g−1) 当量碱度消耗(以CaCO3计)/(g·g−1) 6.4~6.5 5.65 2.82 7.1~7.2 7.44 3.72 6.0~6.1 5.59 2.80 表 6 短期效应实验中不同pH体系的耗碱量
Table 6. Alkali consumption in short-term effect test at different pHs
pH KHCO3消耗量/(g·g−1) 当量碱度消耗(以CaCO3计)/(g·g−1) 6.1±0.1 10.58 5.29 6.6±0.1 11.46 5.73 7.2±0.1 14.23 7.12 7.9±0.1 22.78 11.39 -
[1] LI T, ZHANG L, AI W, et al. A modified MBR system with post advanced purification for domestic water supply system in 180-day CELSS: Construction, pollutant removal and water allocation[J]. Journal of Environmental Management 2018, 222: 37-43. [2] GUO S S, MAO R X, ZHANG L L, et al. Progress and prospect of research on controlled ecological life support technique[J]. Reach, 2017, 6: 1-10. doi: 10.1016/j.reach.2017.06.002 [3] 张良长, 李婷, 余青霓, 等. 4人180天集成实验环控生保系统设计及运行概况[J]. 航天医学与医学工程, 2018, 31(2): 273-281. [4] ZHANG L, LI T, AI W, et al. Water management in a controlled ecological life support system during a 4-person-180-day integrated experiment: Configuration and performance[J]. Science of the Total Environment, 2019, 651: 2080-2086. doi: 10.1016/j.scitotenv.2018.10.080 [5] ZABEL P, BORNEMANN G, TAJMAR M, et al. Yield of dwarf tomatoes grown with a nutrient solution based on recycled synthetic urine[J]. Life Sciences in Space Research, 2019, 20: 62-71. doi: 10.1016/j.lssr.2019.01.001 [6] DENG S, XIE B, LIU H. The recycle of water and nitrogen from urine in bioregenerative life support system[J]. Acta Astronautica, 2016, 123: 86-90. doi: 10.1016/j.actaastro.2016.03.007 [7] HAGOPIAN D S, RILEY J G. A closer look at the bacteriology of nitrification[J]. Aquacultural Engineering, 1998, 18: 223-244. doi: 10.1016/S0144-8609(98)00032-6 [8] ZHANG F, YANG H, WANG J, et al. Effect of free ammonia inhibition on NOB activity in high nitrifying performance of sludge[J]. RSC Advances, 2018, 8(56): 31987-31995. doi: 10.1039/C8RA06198J [9] SEUNTJENS D, HAN M, KERCKHOF F M, et al. Pinpointing wastewater and process parameters controlling the AOB to NOB activity ratio in sewage treatment plants[J]. Water Research, 2018, 138: 37-46. doi: 10.1016/j.watres.2017.11.044 [10] CHENG Z, WEI Y, GAO M, et al. Development of a combined anaerobic and aerobic membrane bioreactor for wastewater treatment and reclamation in terrestrial-based Controlled Ecological Life Support System[J]. Water Science & Technology:Water Supply, 2018, 19(3): 718-724. [11] OOSTERHUIS M, LOOSDRECHT V, M C M. Nitrification of urine for H2S control in pressure sewers[J]. Water Practice and Technology, 2009, 4(3):WPT2009059. [12] 王优, 汪形艳, 张良长, 等. 两级MBfR工艺处理高强度生活废水能力研究[J]. 化工学报, 2020, 71(5): 2363-2372. [13] VEROSTKO C E, CARRIER C, GB TECH I. Ersatz wastewater formulations for testing water recovery systems[J]. Sae Technical Papers, 2004, 113: 1008-1024. [14] ALLEMAN J E. Elevated nitrite occurrence in biological wastewater treatment systems[J]. Water Science and Technology, 1985, 17(2/3): 409-419. doi: 10.2166/wst.1985.0147 [15] DOWNING A L, PAINTER H A, KNOWLES G. Nitrification in the activated sludge process[J]. Journal of the Institute of Sewage Purification, 1964: 130-153. [16] PENG L, QIU H, LI S, et al. The mitigation effect of free ammonia and free nitrous acid on nitrous oxide production from the full-nitrification and partial-nitritation systems[J]. Bioresource Technology, 2022: 128564. [17] 杨宏, 姚仁达. pH和硝化细菌浓度对氨氮氧化速率的影响[J]. 环境工程学报, 2017, 11(5): 2660-2665. doi: 10.12030/j.cjee.201512155 [18] NIU X, HAN X, JIN Y, et al. Aerobic granular sludge treating hypersaline wastewater: Impact of pH on granulation and long-term operation at different organic loading rates[J]. Journal Environmental Management, 2023, 330: 117164. [19] LIU Y, NGO H H, GUO W, et al. The roles of free ammonia (FA) in biological wastewater treatment processes: A review[J]. Environment International, 2019, 123: 10-19. doi: 10.1016/j.envint.2018.11.039 [20] ANTHONISEN A, LOEHR R, PRAKASAM T, et al. Inhibition of nitrification by ammonia and nitrous acid[J]. Water Pollution Control Federation, 1976, 48(5): 835-852. [21] ZHOU Y, OEHMEN A, LIM M, et al. The role of nitrite and free nitrous acid (FNA) in wastewater treatment plants[J]. Water Research, 2011, 45(15): 4672-4682. doi: 10.1016/j.watres.2011.06.025 [22] CIUDAD G, GONZALEZ R, BORNHARDT C, et al. Modes of operation and pH control as enhancement factors for partial nitrification with oxygen transport limitation[J]. Water Res, 2007, 41(20): 4621-4629. doi: 10.1016/j.watres.2007.06.036 [23] 高兰, 钟振兴, 艾庆华, 等. CIBR污泥对生活污水中氨氮的吸附性能分析[J]. 环境工程, 2019, 37(8): 66-69. doi: 10.13205/j.hjgc.201908012 [24] WANG L, ZHENG P, ABBAS G, et al. Enrichment and characterization of acid-tolerant nitrifying sludge[J]. Journal of Environmental Management, 2016, 184: 196-203. [25] ALBINA P, DURBAN N, BERTRON A, et al. Nitrate and nitrite bacterial reduction at alkaline pH and high nitrate concentrations, comparison of acetate versus dihydrogen as electron donors[J]. Journal Environmental Management, 2021, 280: 111859. [26] 张昕, 吴长峰, 于雪, 等. pH值对亚硝酸盐氧化菌动力学及功能基因的影响[J]. 中国环境科学, 2020, 40(4): 1537-1544. doi: 10.3969/j.issn.1000-6923.2020.04.019 [27] DOWNING L S, NERENBERG R. Total nitrogen removal in a hybrid, membrane-aerated activated sludge process[J]. water research, 2008, 42: 3697-3708. doi: 10.1016/j.watres.2008.06.006 [28] WANG Z, MENG Y, ZHU-BARKER X, et al. Responses of nitrification and ammonia oxidizers to a range of background and adjusted pH in purple soils[J]. Geoderma, 2019, 334: 9-14. doi: 10.1016/j.geoderma.2018.07.038 [29] 遇光禄, 喻立军, 唐颖栋. pH对高浓度氨氮短程硝化抑制动力学的影响[J]. 环境污染与防治, 2013, 35(6): 65-68. doi: 10.3969/j.issn.1001-3865.2013.06.013 [30] PAEPE J D, PAEPE K D, GòDIA F, et al. Bio-electrochemical COD removal for energy-efficient, maximum and robust nitrogen recovery from urine through membrane aerated nitrification[J]. Water Research, 2020, 185: 116-223.