Research on the enhanced treatment of organic matter in drinking water plant based on micro-nano bubble ozone aeration
-
摘要:
为提升饮用水厂原水混凝及前/后臭氧处理等重要工艺段的有机物去除率,对比研究了微纳米气泡(MNBs)与普通曝气盘2种曝气方式下的臭氧传质效率,开展了MNBs对水厂原水混凝效果影响小试,并对2种曝气方式下前/后臭氧处理工艺段有机物及藻类等的去除率进行研究。结果表明:1)本研究中的微气泡发生器产生纳米气泡数量为1.2×108个/mL,中值粒径显著低于100 μm,有利于MNBs臭氧(MNBs-O3)在水中停留较长时间;在水厂原水中加入12.5%(体积比)的MNBs水时,MNBs吸附疏水性有机物及产生羟基自由基的特征可以显著提高混凝沉淀效果,使UV254下降幅度达到15%。2)在前臭氧处理过程中,原水经MNBs-O3处理后,出水110 kDa峰消失而小于1 Da部分出现新峰,五日生化需氧量(BOD5)的去除率约为15%(远低于普通曝气盘的50%)且总有机碳与UV254未发生显著变化;在后臭氧处理过程中,MNBs-O3处理后BOD5上升了40%,TOC上升了36%,UV254则先上升后下降。该结果说明MNBs-O3在前臭氧处理过程中可以将芳香族有机物分解为含氧类链状有机物,MNBs-O3较长的停留时间使其更易将大分子有机物转换为小分子有机物,而后臭氧处理过程中MNBs-O3可以进一步提高对水中残留的难降解有机物的去除率。3)MNBs-O3对藻类的去除率可达25%,且MNBs-O3处理不会增加水中溴酸盐浓度,后续可借助MNBs的气浮功能进一步提升其效率。尽管MNBs替代普通曝气盘使电能消耗上升约30%,但MNBs会大幅缩短进气时间,减少O3使用量。本研究结果为MNBs在原水混凝及前/后臭氧处理过程中的应用建立了理论基础。
-
关键词:
- 微纳米气泡(MNBs) /
- 臭氧 /
- 有机物 /
- 饮用水 /
- 传质效率
Abstract:To improve the organic matter removal efficiency of important process stages such as raw water coagulation and pre/post ozone treatment in water plants, a comparative study was conducted on the ozone mass transfer efficiency under two aeration modes, i.e., micro-nano bubble (MNBs) aeration and ordinary aeration disc aeration. A small-scale experiment was conducted to investigate the impact of MNBs on the coagulation effect of raw water in water plants and study the removal efficiency of organic matter and algae in the pre and post-ozone treatment process stages under two aeration modes. The results showed that the number of nanobubbles produced by the microbubble generator in this study was 1.2×106 mL−1. Therefore, MNBs ozone (MNBs-O3) had a longer residence time in water, and the utilization rate of MNBs-O3 gradually increased within 20 minutes, while the ordinary aeration tray showed a trend of first increasing and then rapidly decreasing. When 12.5% of MNBs water was added to the raw water, the adsorption of hydrophobic organic compounds and the generation of hydroxyl radicals by MNBs could significantly improve the coagulation and precipitation effect of the raw water, and the decrease in UV254 could reach more than 15%. The longer residence time also made it easier for MNBs-O3 to convert large organic molecules into small molecules during the pre-ozone process. The molecular weight distribution results showed that 110 kDa peak disappeared and new peaks appeared in the parts less than 1 Da. The removal efficiency of BOD5 was about 15% (much lower than 50% of ordinary aeration discs), and there was no significant change in TOC and UV254. During the post-ozone process, BOD5 of MNBs-O3 group increased by 40%, and TOC increased by 36%, while UV254 first increased and then decreased. The above results indicate that MNBs-O3 can decompose aromatic organic compounds into oxygen-containing chain-like organic compounds during the pre-ozone process, and some large molecule organic compounds can be degraded into small molecules, which is helpful for the treatment of subsequent process stages. While during the post-ozone process, MNBs-O3 can further improve the treatment efficiency of residual recalcitrant organic compounds in water. In addition, under the conditions of this study, the reduction rate of algae by MNBs-O3 could reach 25% and MNBs-O3 treatment did not increase the bromate concentration in water, and its efficiency could be further improved through the air flotation function of MNBs in the future. Although replacing ordinary aeration discs with MNBs increases electricity consumption by about 30%, MNBs significantly shorten the intake time and reduce O3 usage. In summary, this study establishes a theoretical basis for the application of MNBs in raw water coagulation and pre/post-ozone treatment processes.
-
Key words:
- micro-nano bubbles (MNBs) /
- ozone /
- organic matter /
- drinking water /
- mass transfer efficiency
-
-
[1] 王兴林. 臭氧微纳米气泡降解饮用水中典型嗅味物质的效能与机理研究[D]. 济南: 山东建筑大学, 2023. [2] 黄晓江. 微纳米气泡共混凝用于强化混凝效能及缓解超滤膜污染的研究[D]. 西安: 西安建筑科技大学, 2023. [3] TANAKA S, KASTENS S, FUJIOKA S, et al. Mass transfer from freely rising microbubbles in aqueous solutions of surfactant or salt[J]. Chemical Engineering Journal,2020,387:121246. doi: 10.1016/j.cej.2019.03.122 [4] PARMAR R, MAJUMDER S K. Microbubble generation and microbubble-aided transport process intensification:a state-of-the-art report[J]. Chemical Engineering and Processing: Process Intensification,2013,64:79-97. doi: 10.1016/j.cep.2012.12.002 [5] 马艳, 张鑫, 韩小蒙, 等. 臭氧微纳米气泡技术在水处理中的应用进展[J]. 净水技术,2019,38(8):64-67.MA Y, ZHANG X, HAN X M, et al. Application of micro-nano ozone bubble technology in water treatment: a review[J]. Water Purification Technology,2019,38(8):64-67. [6] 郭云霞, 蔡小垒, 李爽, 等. 文丘里串联结构气泡发生器气液混合和发泡特性试验[J]. 环境工程技术学报,2022,12(4):1350-1358.GUO Y X, CAI X L, LI S, et al. Experimental study on gas-liquid mixing and foaming characteristics of Venturi series bubble generator[J]. Journal of Environmental Engineering Technology,2022,12(4):1350-1358. [7] 孙文杰. 微纳米气泡强化纳滤膜处理诺氟沙星抗生素废水效能与机制[D]. 济南: 济南大学, 2023. [8] 毛如寅. 基于微纳米气泡的协同技术去除水中嗅味物质研究[D]. 浙江大学, 2023. [9] SOYLUOGLU M, KIM D, ZAKER Y, et al. Stability of oxygen nanobubbles under freshwater conditions[J]. Water Research,2021,206:117749. doi: 10.1016/j.watres.2021.117749 [10] ATKINSON A J, APUL O G, SCHNEIDER O, et al. Nanobubble technologies offer opportunities to improve water treatment[J]. Accounts of Chemical Research,2019,52(5):1196-1205. doi: 10.1021/acs.accounts.8b00606 [11] HU L M, XIA Z R. Application of ozone micro-nano-bubbles to groundwater remediation[J]. Journal of Hazardous Materials,2018,342:446-453. doi: 10.1016/j.jhazmat.2017.08.030 [12] 马汇源. 微纳米O3-BAC工艺优化与除污染特性研究[D]. 济南: 山东建筑大学, 2023. [13] 国家市场监督管理总局, 国家标准化管理委员会. 生活饮用水标准检验方法: GB/T 5750.1~5750.13—2023[S/OL]2024-04-06]. https://www.wooking.com/show/131.html. [14] 曾东宝, 丘茂盛, 刘林斌. 离子色谱法测定氯消毒饮用水中溴化物的方法研究[J]. 城镇供水,2017(1):43-45. [15] 韩瑾, 李星, 杨艳玲, 等. 东江水源水有机物分子量分布及其处理工艺选择[J]. 北京工业大学学报,2013,39(1):87-91.HAN J, LI X, YANG Y L, et al. Organic matter molecular weight distribution and process selection for the raw water of east river[J]. Journal of Beijing University of Technology,2013,39(1):87-91. [16] American Public Health Association, American Water Works Association, Water Environment Federation. Standard methods for the examination of water and wastewater[S]. 15th ed. Washington D C: Amer Public Health Association, 1985. [17] 吴世萍. 太湖流域某市水源水及制水工艺中藻类及其代谢物的动态变化[D]. 南京: 东南大学, 2016. [18] 初里冰, 邢新会, 于安峰, 等. 微米气泡强化臭氧氧化的作用机理研究[J]. 环境化学,2007,26(5):622-625.CHU L B, XING X H, YU A F, et al. Enhancement mechanism of ozonation by microbubbles[J]. Environmental Chemistry,2007,26(5):622-625. [19] 刘颖, 金鑫, 金鹏康, 等. 溶气气浮的微气泡影响因素及其与絮体的结合特性[J]. 中国给水排水,2018,34(5):1-5.LIU Y, JIN X, JIN P K, et al. Characteristics of microbubbles and microbubble-flocs in dissolved ozone flotation process[J]. China Water & Wastewater,2018,34(5):1-5. [20] 高康宁. 微气泡耦合洗涤剂脱除土壤中典型有机物-重金属复合污染物及机理研究[D]. 上海: 东华大学, 2022. [21] 董秉直, 吴炜玮, 阎婧. 采用HPSEC-UV-TOC研究臭氧预氧化缓解膜污染的机理[J]. 河南科技,2015(21):83-84. [22] 周琰琰, 刘振鸿, 马春燕, 等. 基于BioWin的微生物呼吸速率和B/C值相关性的模拟[J]. 环境工程,2017,35(12):1-5.ZHOU Y Y, LIU Z H, MA C Y, et al. Simulation of correlation between microbial respiration rate and B/C ratio using biowin software[J]. Environmental Engineering,2017,35(12):1-5. [23] 檀雅琴. 高锰酸钾氧化降解多种有机物的研究[D]. 上海: 上海交通大学, 2014. [24] 王健. 高效臭氧溶气氧化技术研究[D]. 扬州: 扬州大学, 2023. [25] 方平, 陆少鸣, 刘姣. 生物砂滤池对有机物和氨氮的去除[J]. 环境科学与技术,2006,29(12):73-74.FANG P, LU S M, LIU J. Removal of organic matter and NH3-N by biological sand filter[J]. Environmental Science & Technology,2006,29(12):73-74. [26] AUDENAERT W T M, VANDIERENDONCK D, van HULLE S W H, et al. Comparison of ozone and HO· induced conversion of effluent organic matter (EfOM) using ozonation and UV/H2O2 treatment[J]. Water Research,2013,47(7):2387-2398. doi: 10.1016/j.watres.2013.02.003 [27] 蔡云龙,高乃云,谭章荣,等. 镇江市饮用水有机物分子量分布特性的研究[J]. 净水技术,2005,24(5):12-16.CAI Y L,GAO N Y,TAN Z R,et al. Study on the characteristics of molecular weight distributions of organic matters in Zhenjiang City's drinking water[J]. Water Purification Technology,2005,24(5):12-16. [28] 季华,PERRIN D,杨燕华.预臭氧/混凝/气浮工艺去除水库原水中的藻类[J].中国给水排水,2016,32(21):60-62.JI H,PERRIN D,YANG Y H.Removal of algae from raw water of reservoir with pre-ozonation/coagulation/flotation process[J]. China Water & Wastewater,2016,32(21):60-62. [29] ZHANG L H, ZHENG J, TIAN S L, et al. Effects of Al3+ on the microstructure and bioflocculation of anoxic sludge[J]. Journal of Environmental Sciences (China),2020,91:212-221. doi: 10.1016/j.jes.2020.02.010 [30] 王建, 胡淑恒, 卓胜君, 等. 微纳米气泡藻水分离试验研究[J]. 长江科学院院报,2017,34(4):20-23.WANG J, HU S H, ZHUO S J, et al. Experimental investigation on separating algae from water using micro-nano bubble air flotation process[J]. Journal of Yangtze River Scientific Research Institute,2017,34(4):20-23. [31] 黄青, 刘爱荣, 张立娟. 微纳米气泡特性及在土壤环境改善中的应用[J]. 环境工程技术学报,2022,12(4):1324-1332.HUANG Q, LIU A R, ZHANG L J. Characteristics of micro-nanobubbles and their applications in soil environment improvement[J]. Journal of Environmental Engineering Technology,2022,12(4):1324-1332. [32] 刘栋. 臭氧预氧化对水中消毒副产物的影响研究[D]. 长春: 吉林建筑大学, 2017. ◇