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我国城镇污水厂进水C/N普遍较低,常规生物处理技术在处理此类低C/N污水时存在碳源不足、抗冲击负荷能力差等问题,难以实现高效脱氮[1-4]. 目前很多地方标准已经将出水TN浓度限制在10 mg·L−1以下,随着排放标准的提高,污水深度脱氮问题愈显突出. 低C/N污水碳源供应不足是限制生物脱氮效率的主要因素[5],而直接向污水中投加碳源的方式会导致成本增加、副产物增多等问题[6-8],并可能导致出水COD超标[9]. 因此,寻找一种经济、高效、稳定的工艺对深度脱氮有重要意义.
此前,本课题组开发了一种两段SBR缺氧-好氧生物深度脱氮工艺[10],主流程是进水-缺氧-沉淀(回流过程中增加好氧反应)-缺氧-好氧-沉淀-出水,此工艺对低C/N污水具有较高的脱氮效率,但是该工艺第二段缺氧-好氧过程运行效率较低,出水TN平均浓度为6.5 mg·L−1左右,TN平均去除率仅为47.9%. 主要是原污水经过第一段缺氧-沉淀(回流好氧)-出水处理后,污水COD浓度较低(一段处理后COD浓度常常只剩下40—50 mg·L−1),出水C/N为3.8,传统活性污泥难以适应,导致第二段脱氮效率低下.
为了解决经该工艺第一段处理后污水浓度及C/N较低难以高效脱氮的问题,实验利用颗粒玉米芯作为轻质挂膜载体附着生物膜,构建了活性污泥-悬浮生物膜复合系统,对低浓度低C/N污水深度脱氮性能进行探究. 玉米芯填料表面具有规则的蜂窝状结构,表面粗糙且比表面积大,微生物在其表面更易形成密实的生物膜. 填料外层与污水直接接触,易于吸收溶解氧和养分,形成由好氧和兼氧微生物组成的好氧层;内层则形成由厌氧和兼氧微生物组成的厌氧层,通过生物膜的周期更新降解污水中的污染物. 本文探索了该复合系统用于低浓度低C/N污水处理的技术可行性,为低浓度污水深度脱氮提供一定的技术参考.
活性污泥-悬浮生物膜系统处理低C/N污水深度脱氮性能
Deep nitrogen removal performance of activated sludge suspended biofilm system for treating low C/N ratio wastewater
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摘要: 通过农业废弃物玉米芯悬浮生长生物膜的载体,构建了活性污泥-悬浮生物膜混合系统,以SBR工艺运行方式对低浓度低C/N污水的深度脱氮性能进行了研究. 探究了挂膜启动阶段系统脱氮效果;在工艺稳定运行后,考察了温度、HRT、DO、进水C/N、进水pH等参数对工艺脱氮性能的影响. 经过24 d 挂膜后,结合污染物去除情况及镜检显示生物膜挂膜成功. 运行结果表明,以预处理后的生活污水作为模拟原水,控制反应温度为26—30 ℃,HRT=8 h,COD/TN为(4.0±0.1),DO=(2.2±0.1) mg·L−1,进水pH=(8.0± 0.1)的条件下,系统达到最佳运行条件,COD、
${\rm{NH}}_4^{+} $ -N、TN平均去除率分别为70.2%、94.8%和80.8%,平均出水COD、${\rm{NH}}_4^{+} $ -N、TN浓度分别为14.89 mg·L−1、0.57 mg·L−1 和2.40 mg·L−1. 好氧阶段DO浓度对TN去除率有一定的影响,当好氧阶段DO浓度为(2.2±0.1)mg·L−1时,TN去除率达到峰值84.38%. 结果表明,活性污泥-悬浮生物膜混合系统处理低浓度低C/N污水具有优良性能,为低浓度低C/N污水的深度脱氮及玉米芯的资源化利用提供新的思路.Abstract: Agricultural waste corncob was used to construct an activated sludge-suspended biofilm mixed system.Deep nitrogen removal performance of low concentration and C/N ratio wastewater was studied in the SBR process operation mode. The nitrogen removal effect of the system at the start-up stage of biofilm formation was explored; when the process was at a steady stage, the effects of parameters such as temperature, HRT, DO, influent C/N ratio and influent pH on the nitrogen removal performance of the process were investigated. After 24 days , it showed that the biofilm was considered to be successfully formed combined with the removal of pollutants and microbial images of corncob . Pretreated domestic wasterwater was used as the simulated raw water and reaction temperature was controlled to be 26—30 ℃, HRT=8 h, COD/TN=(4.0±0.1), and pH of influent water was (8.0±0.1). The results showed that average removal ratios of COD, NH4+-N and TN were 70.2%, 94.8% and 80.8%, respectively, The average effluent concentrations of COD, NH4+-N and TN were 14.89, 0.57, 2.40 mg·L−1, respectively. The DO concentration in aerobic phase had a certain influence on TN removal ratio. When the DO concentration in aerobic phase was (2.2±0.1) mg·L−1, the TN removal ratio reached a peak value of 84.38%. The above results showed that the activated sludge-suspended biofilm mixed system had an excellent performance in the treatment of low concentration and C/N ratio wastewater, which provided a new idea for the deep nitrogen removal of low concentration and C/N ratio wastewater and resource utilization of corncob.-
Key words:
- corncob /
- suspended biofilm /
- mixed system /
- low concentration /
- low C/N ratio /
- deep nitrogen removal
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表 1 实验水质
Table 1. Experimental water quality
水质指标
Water quality indexes原水水质
Raw water quality模拟污水水质
Simulated wastewater quality范围
Range平均值
Average value范围
Range平均值
Average valuepH 6.59—7.88 7.48 6.54—7.79 7.35 COD/(mg·L−1) 98.26—316.18 161.35 42.64—53.12 47.26 -N/(mg·L−1)${\rm{NH}}_4^{+} $ 23.73—43.19 34.75 9.82—12.04 10.68 TN/(mg·L−1) 30.43—51.67 41.43 11.28—13.67 12.32 -
[1] SONG C, ZHAO C, WANG Q, et al. Impact of carbon/nitrogen ratio on the performance and microbial community of sequencing batch biofilm reactor treating synthetic mariculture wastewater [J]. Journal of Environmental Management, 2021, 298: 113528. doi: 10.1016/j.jenvman.2021.113528 [2] 王建辉, 游庆国, 申渝, 等. 短程反硝化-厌氧氨氧化耦合脱氮工艺影响因素与调控研究进展 [J]. 环境化学, 2021, 40(4): 1216-1231. doi: 10.7524/j.issn.0254-6108.2020091302 WANG J H, YOU Q G, SHEN Y, et al. Research advances on influence factors and regulation of Partial denitrification and Anammox coupling denitrification process [J]. Environmental Chemistry, 2021, 40(4): 1216-1231(in Chinese). doi: 10.7524/j.issn.0254-6108.2020091302
[3] 毛世超, 王燕萍, 陈芳媛. 低碳氮比废水好氧颗粒污泥系统稳定性及微生物种群多样性研究 [J]. 环境化学, 2021, 40(3): 904-913. doi: 10.7524/j.issn.0254-6108.2019101105 MAO S C, WANG Y P, CHEN F Y. Stability and microbial diversity of the aerobic granular sludge under low carbon to nitrogen ratio [J]. Environmental Chemistry, 2021, 40(3): 904-913(in Chinese). doi: 10.7524/j.issn.0254-6108.2019101105
[4] WU B, DAI X, CHAI X. Critical review on dewatering of sewage sludge: Influential mechanism, conditioning technologies and implications to sludge re-utilizations [J]. Water Research, 2020, 180: 115912. doi: 10.1016/j.watres.2020.115912 [5] YANG S S, YU X L, DING M Q, et al. Simulating a combined lysis-cryptic and biological nitrogen removal system treating domestic wastewater at low C/N ratios using artificial neural network [J]. Water Research, 2021, 189: 116576. doi: 10.1016/j.watres.2020.116576 [6] XU X, MA B, LU W, et al. Effective nitrogen removal in a granule-based partial-denitrification/anammox reactor treating low C/N sewage [J]. Bioresource Technology, 2020, 297: 122467. doi: 10.1016/j.biortech.2019.122467 [7] CHENG Y, LI J Y, REN X, et al. High efficiency of simultaneous nitrification, denitrification, and organics removal in the real-scale treatment of high C/N ratio food-processing wastewater using micro-aerobic reactors [J]. Biochemical Engineering Journal, 2022, 177: 108218. doi: 10.1016/j.bej.2021.108218 [8] FU X, HOU R, YANG P, et al. Application of external carbon source in heterotrophic denitrification of domestic sewage: A review [J]. Science of the Total Environment, 2022: 153061. [9] CASTELLAR J A C, FORMOSA J, FERNÁNDEZ A I, et al. Cork as a sustainable carbon source for nature-based solutions treating hydroponic wastewaters–Preliminary batch studies [J]. Science of the Total Environment, 2019, 650: 267-276. doi: 10.1016/j.scitotenv.2018.08.365 [10] 唐玉朝, 陈徐庆, 薛莉娉, 等. 两段SBR串联工艺处理低C/N城市污水的效率研究 [J]. 环境科学与技术, 2022, 45(5): 15-21. TANG Y C, CHEN X Q, XUE L P, et al. Study on biological denitrification efficiency of two-stage sbr reactor for treatment of municipal wastewater with low C/N ratio [J]. Environmental Science & Technology, 2022, 45(5): 15-21(in Chinese).
[11] CAI X, HU C H, WANG J, et al. Efficient high-solids enzymatic hydrolysis of corncobs by an acidic pretreatment and a fed-batch feeding mode [J]. Bioresource Technology, 2021, 326: 124768. doi: 10.1016/j.biortech.2021.124768 [12] 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. State Environmental Protection Administration. Water and Wastewater Monitoring and Analysis Methods [M]. 4th edition. Beijing: China Environmental Science Press, 2002(in Chinese).
[13] LI L, HE Z, LIANG T, et al. Colonization of biofilm in wastewater treatment: A review [J]. Environmental Pollution, 2022, 293: 118514. doi: 10.1016/j.envpol.2021.118514 [14] HONG Q K, ZHANG H L, ZHANG S X. Study on the efficiency treatment of polluted water by biofilm process filled with bamboo filler [J]. Strategic Planning for Energy and the Environment, 2022, 41(3): 4131. [15] ZHANG L, CUI B, YUAN B, et al. Denitrification mechanism and artificial neural networks modeling for low-pollution water purification using a denitrification biological filter process [J]. Separation and Purification Technology, 2021, 257: 117918. doi: 10.1016/j.seppur.2020.117918 [16] LIU J, FU X, YUAN R, et al. Carbon sources derived from corncobs enhanced nitrogen removal in SBBR treating low C/N domestic sewage [J]. Process Safety and Environmental Protection, 2022, 166: 628-637. doi: 10.1016/j.psep.2022.08.063 [17] WANG Z, ZHENG M, HE C, et al. Enhanced treatment of low-temperature and low carbon/nitrogen ratio wastewater by corncob-based fixed bed bioreactor coupled sequencing batch reactor [J]. Bioresource Technology, 2022, 351: 126975. doi: 10.1016/j.biortech.2022.126975 [18] WANG F, XU S, LIU L, et al. One-stage partial nitrification and anammox process in a sequencing batch biofilm reactor: Start-up, nitrogen removal performance and bacterial community dynamics in response to temperature [J]. Science of the Total Environment, 2021, 772: 145529. doi: 10.1016/j.scitotenv.2021.145529 [19] 孙洪伟, 陈翠忠, 吴长峰, 等. 温度对SBR生物脱氮效能及胞外聚合物的影响 [J]. 环境科学, 2017, 38(11): 4648-4655. SUN H W, CHEN C Z, WU C F, et al. Effect of Temperature on Nitrogen Removal Performance and the Extracellular Polymeric Substance (EPS) in a Sequencing Batch Reactor (SBR) [J]. Environmental Science, 2017, 38(11): 4648-4655(in Chinese).
[20] WAGNG X, YE C, ZHANG Z, et al. Effects of temperature shock on N2O emissions from denitrifying activated sludge and associated active bacteria [J]. Bioresource Technology, 2018, 249: 605-611. doi: 10.1016/j.biortech.2017.10.070 [21] BHATTACHARYA R, MAZUMDER D. Simultaneous nitrification and denitrification in moving bed bioreactor and other biological systems [J]. Bioprocess and Biosystems Engineering, 2021, 44(4): 635-652. doi: 10.1007/s00449-020-02475-6 [22] LI C, LIU S, MA T, et al. Simultaneous nitrification, denitrification and phosphorus removal in a sequencing batch reactor (SBR) under low temperature [J]. Chemosphere, 2019, 229: 132-141. doi: 10.1016/j.chemosphere.2019.04.185 [23] HENDRASARIE N, ZARFANDI F I, ROSARIAWARI F, et al. Addition of fixed bed biofilm in sequencing batch reactor to remove carbon-nitrogen for apartment wastewater[C]//IOP Conference Series: Materials Science and Engineering. IOP Publishing, 2021, 1125(1): 012089. [24] WAN A, ZHAO B, XIE Y, et al. Study on the effect of new type of suspended carrier on oxygen mass transfer characteristics [J]. Environmental Science and Pollution Research, 2021, 28(27): 36911-36923. doi: 10.1007/s11356-021-14371-x [25] RAJTA A, BHATIA R, SETIA H, et al. Role of heterotrophic aerobic denitrifying bacteria in nitrate removal from wastewater [J]. Journal of applied microbiology, 2020, 128(5): 1261-1278. doi: 10.1111/jam.14476 [26] XIONG R, YU X, ZHANG Y, et al. Comparison of agricultural wastes and synthetic macromolecules as solid carbon source in treating low carbon nitrogen wastewater [J]. Science of the Total Environment, 2020, 739: 139885. doi: 10.1016/j.scitotenv.2020.139885 [27] 凌宇, 赵远哲, 王海燕, 等. HRT对A/O-BF处理低碳氮比农村生活污水脱氮的影响 [J]. 环境科学研究, 2021, 34(4): 927-935. LING Y, ZHAO Y Z, WANG H Y, et al. Effects of HRT on A/O-BF Nitrogen Removal of Low C/N Rural Domestic Sewage [J]. Research of Environment Sciences, 2021, 34(4): 927-935(in Chinese).
[28] YAN L, LIU S, LIU Q, et al. Improved performance of simultaneous nitrification and denitrification via nitrite in an oxygen-limited SBR by alternating the DO [J]. Bioresource Technology, 2019, 275: 153-162. doi: 10.1016/j.biortech.2018.12.054 [29] ZHENG Z, HUANG S, BIAN W, et al. Enhanced nitrogen removal of the simultaneous partial nitrification, anammox and denitrification (SNAD) biofilm reactor for treating mainstream wastewater under low dissolved oxygen (DO) concentration [J]. Bioresource Technology, 2019, 283: 213-220. doi: 10.1016/j.biortech.2019.01.148 [30] PAN Z, ZHOU J, LIN Z, et al. Effects of COD/TN ratio on nitrogen removal efficiency, microbial community for high saline wastewater treatment based on heterotrophic nitrification-aerobic denitrification process [J]. Bioresource Technology, 2020, 301: 122726. doi: 10.1016/j.biortech.2019.122726 [31] CAO S, DU R, PENG Y, et al. Novel two stage partial denitrification (PD)-Anammox process for tertiary nitrogen removal from low carbon/nitrogen (C/N) municipal sewage [J]. Chemical Engineering Journal, 2019, 362: 107-115. doi: 10.1016/j.cej.2018.12.160 [32] LU W, ZHANG Y, WANG Q, et al. Achieving advanced nitrogen removal in a novel partialdenitrification/anammox-nitrifying (PDA-N) biofilter process treating low C/N ratio municipal wastewater [J]. Bioresource Technology, 2021, 340: 125661. doi: 10.1016/j.biortech.2021.125661 [33] HU B, QUAN J, HUANG K, et al. Effects of C/N ratio and dissolved oxygen on aerobic denitrification process: A mathematical modeling study [J]. Chemosphere, 2021, 272: 129521. doi: 10.1016/j.chemosphere.2020.129521 [34] CHEN X, ZHANG Q, ZHU Y, et al. Response of wastewater treatment performance, microbial composition and functional genes to different C/N ratios and carrier types in MBBR inoculated with heterotrophic nitrification-aerobic denitrification bacteria [J]. Bioresource Technology, 2021, 336: 125339. doi: 10.1016/j.biortech.2021.125339 [35] ALBINA P, DURBAN N, BERTRON A, et al. Influence of hydrogen electron donor, alkaline pH, and high nitrate concentrations on microbial denitrification: a review [J]. International Journal of Molecular Sciences, 2019, 20(20): 5163. doi: 10.3390/ijms20205163 [36] 王登敏, 张立秋, 李淑更, 等. 玉米芯固体碳源生物膜SND处理低碳源污水[J]. 环境科学与技术, 2018, 41(10): 99-104. WANG D M, ZHANG L Q, LI S G, et al. SND treatment of low-carbon source sewage with corncob solid carbon source biofilm [J]. Environmental Science & Technology 2018, 41(10): 99-104(in Chinese).
[37] CAO X, ZHOU X, XUE M, et al. Evaluation of nitrogen removal and N2O emission in a novel anammox coupled with sulfite-driven autotrophic denitrification system: Influence of pH [J]. Journal of Cleaner Production, 2021, 321: 128984. doi: 10.1016/j.jclepro.2021.128984 [38] SRIWIRIYARAT T, NUCHLEK P. Effects of pH on extracellular polymeric substances compositions of biofilm in integrated fixed film activated sludge process [J]. International Journal of Environmental Science and Technology, 2022, 19(1): 73-84. doi: 10.1007/s13762-021-03316-z [39] WANG J, RONG H, GAO Y, et al. Factors affecting simultaneous nitrification and denitrification (SND) in a moving bed sequencing batch reactor (MBSBR) system as revealed by microbial community structures [J]. Bioprocess and Biosystems Engineering, 2020, 43(10): 1833-1846. doi: 10.1007/s00449-020-02374-w -
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