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PAC-UF工艺的膜污染特性及膜污染物质研究 总被引:2,自引:0,他引:2
针对污水处理厂二级出水在超滤膜(UF)工艺和粉末活性炭-超滤(PAC-UF)工艺中的运行,分析粉末活性炭(PAC)对膜污染的影响,并采用三维荧光光谱分析等方法分析膜污染的主要成分。试验分析表明,两种工艺中UF膜的膜通量均呈下降趋势而后趋于平缓,但PAC-UF工艺的下降趋势相对缓慢,说明PAC可以延缓膜污染的形成,但无法阻止膜污染的发生。根据三维荧光的分析,二级出水中的主要污染物为富里酸类物质和腐殖酸类腐殖质,溶解性微生物代谢产物和腐殖酸类腐殖质是造成可逆污染的物质,该污染物通过物理反冲洗可以被大部分去除;通过对碱洗液和酸洗液的分析,推测在PAC-UF工艺中造成UF膜片不可逆污染的物质为酪氨酸类蛋白质、色氨酸类蛋白质和富里酸类物质,这三种有机物是造成UF膜片不可逆污染的主要原因。 相似文献
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重庆市自来水公司根据有关资料,把加氯点改在二级泵站的水泵吸水口附近,加氯后立即通过水泵的快速混合,从而提高了消毒杀菌效果,在保证出水水质与余氯量的情况下,大大缩短了接触时间。他们的实践经验可供各地进一步探讨。 相似文献
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针对建筑生活热水系统水力停留时间长、余氯含量低、微生物超标等问题,采用二次加氯方式进行二次消毒,研究二次加氯的消毒效能、余氯衰减及消毒副产物生成特性等。结果表明,二次加氯消毒可有效保障生活热水的生物安全性,投加0.2~0.5 mg/L次氯酸钠均可完全灭活细菌总数和总大肠菌群,投加0.3~0.5 mg/L次氯酸钠在24~48 h内持续消毒效果良好。生活热水的余氯衰减速率和三氯甲烷生成量明显高于二次供水,存在消毒副产物超标的风险;随着水温和有机物含量的升高,余氯衰减速率、三氯甲烷生成速率和生成量均明显提高。综合考虑生活热水的生物和化学安全性、水力停留时间和持续消毒作用等方面的要求,0.3 mg/L次氯酸钠为二次加氯消毒的最适宜投加量。研究结果为生活热水系统二次加氯消毒技术的应用和水质安全保障提供了技术支持。 相似文献
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基于新冠病毒存在介水传播的风险,结合北京城市污水再生利用实践,对疫情期间污水再生处理与协同消毒工艺实际运行效果进行研究。结果表明:根据已有研究结果,新冠病毒在水环境中的存活能力及对消毒剂耐受力均弱于粪大肠菌群,在城市污水处理过程中粪大肠菌群可以用来参考指示新冠病毒的灭活。二级处理与深度处理单元的稳定运行,使消毒工艺进水SS5mg/L,有效保障了后续消毒单元的消毒效果。对于臭氧-NaClO协同消毒工艺,臭氧剂量维持在3~5mg/L,NaClO剂量根据水量与清水池容积维持CT值不低于8mg·min/L,可以稳定实现出水粪大肠菌群2CFU/L的消毒效果,同时节省NaClO投加量。对于臭氧-UV-NaClO协同消毒工艺,1~3 mg/L的臭氧投加量能够将紫外透射率提升30%,在设计紫外剂量下(景观用水30mJ/cm~2,城市杂用水80mJ/cm~2),能够达到紫外出水粪大肠菌群2CFU/L;后续根据再生水用途及管网输配要求进行补氯,保障出水余氯达到相应标准。协同消毒工艺通过不同消毒技术的合理选择与运行优化,可以实现粪大肠菌群99.99%以上的去除,出水粪大肠菌群2CFU/L,出水余氯浓度稳定可控,保障了再生水与受纳水体安全。 相似文献
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《给水排水》2019,(12)
针对饮用水中二甲基异莰醇(2-MIB)污染和UV/H_2O_2高级氧化工艺H_2O_2残留问题,构建了UV/H_2O_2/Cl_2组合工艺,并以加标滤后水为原水开展了相关中试研究。基于响应曲面法对UV/H_2O_2工艺去除2-MIB进行参数优化,在此基础上对出水残留H_2O_2采用加氯中和处理,调整NaClO投加量以保证出水符合出厂水余氯要求。最终确定UV/H_2O_2/Cl_2组合工艺运行的最优工况为:当2-MIB为275ng/L时,UV为350mJ/cm~2,H_2O_2投加量6mg/L,NaClO投加量7.5mg/L,在确定的最优工况下连续稳定运行组合工艺,对工艺出水进行检测,结果表明UV/H_2O_2/Cl_2组合工艺对2-MIB去除率达到96.95%,出水余氯值0.4~0.5 mg/L,对TOC、UV_(254)去除率分别达到15.59%、65.71%,能够氧化去除水中大分子有机物,对色氨酸等5种溶解性有机物去除效果良好,且不会带来消毒副产物超标和生物毒性问题,最终出水符合《生活饮用水卫生标准》(GB 5749-2006)对水质的要求。 相似文献
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某再生水厂的供水能力为5万m3/d,采用混凝、沉淀、浸没式微滤、部分反渗透+臭氧工艺。由于出水色度较高,以微滤出水为原水,研究不同工况下臭氧投加量、反应时间对色度去除的影响,并建立多元线性回归模型,根据进水指标及臭氧投量和接触时间预测出水色度,以期获得臭氧氧化处理工艺的最佳运行参数,为该再生水厂的工艺改造和提升出水水质提供支持。 相似文献
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电厂余氯排放对水域环境影响评价方法研究 总被引:3,自引:0,他引:3
为了探讨火(核)电厂冷却系统余氯排放对受纳水域环境影响的范围和程度,本文在以往电厂环境影响研究和评价工作实践的基础上,总结前人的研究成果,针对工程建设的不同阶段和电厂采用的不同加氯方式,提出具体的获得余氯影响范围和程度的方法。对已生产运行的电厂,采用现场直接采样观测方法;对于采用间歇加氯工艺的电厂,采用现场快捷比色实验方法;对已建和拟建电厂,均可采用一级动力学反应数学模型计算方法;对于拟建电厂在资料不充分的情况下,采用二维对流扩散数学模型预测方法。并对这些方法的适用范围进行了分析,列举了相应的应用实例。为研究电厂排放余氯对水环境的影响和这类建设项目环境影响评价及后评估提供了可供选择的工具。 相似文献
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UF911A超声波流量量测系统是根据超声波的有关原理对流量进行测量的装置。文中对该系统的原理、结构、功能和在工程应用中遇到的问题及其解决办法进行了简单介绍。 相似文献
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低频切负荷和低压切负荷的协调优化是离散变量(地点和轮次)和连续变量(各轮的控制量)的混合优化问题。它具有高维时变非线性微分代数方程组的稳定性约束,包括功角有界稳定性和振荡阻尼及代数变量的偏离量,并考虑多工况、多场景、多控制点、多轮次。将其解耦为4个子问题:按控制点的贡献度动态排序优化布点;从有效控制母线数最少和故障严重程度最小的故障开始,逐个故障确定切负荷点和切负荷量,并将已有整定结果作为场景,对余下母线的贡献度动态排序,迭代优化首轮初值;以多工况下各故障的欠切风险和过切风险代价之和最小为目标,按替代前一轮的机会性价比将各控制母线动态排序,确定后续轮的控制量;按解耦优化-迭代协调方式协调低频切负荷和低压切负荷。通过实际系统的算例验证了算法的有效性。 相似文献
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Algogenic organic matter (AOM) was extracted from blue-green algae (cyanobacteria) and its characteristic was determined by various methods including high-pressure size-exclusion chromatography (HP-SEC), hydrophobic and hydrophilic fractionation, molecular weight (MW) fractionation and fluorescence excitation emission matrix (EEM). The results revealed that AOM was hydrophilic fractionation predominantly, accounting for 78%. The specific ultraviolet absorbance of AOM was 1.1 L/(mg m) only. The analysis for MW distribution demonstrated that organic matter greater than 30,000 MW accounted for over 40% and was composed of mostly neutral hydrophilic compound. EEM analyses revealed that protein-like and humic-substances existed in AOM. A test for membrane filtration exhibited that AOM could make ultrafiltration membrane substantial flux decline, which can be attributed to membrane pore clog caused by neutral hydrophilic compound with larger MW. 相似文献
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A pilot UASB reactor coupled with an external ultrafiltration (UF) membrane was operated under three different hydraulic retention times (HRT) for domestic wastewater treatment. The aim was to assess the HRT influence on system performance and fouling. The highest concentrations of COD, total solids, extracellular polymeric substances (EPS) and soluble microbial products (SMP) in UASB effluent and permeate were found when the UASB reactor was operated under the lowest HRT studied (4 hours); although the fulfillment of Mexican Standard for wastewater reclamation was not compromised. This fact could be attributed to the higher shear stress forces inside the UASB reactor when it was operated at low HRT, which promoted the release of biopolymeric substances in its effluent. Besides, the fouling propensity in the UASB effluent was worsened with HRT reduction, by increasing the fouling rate and the specific cake resistance. Based on these results, it is recommended to avoid operating the UASB reactor at low HRTs (less than 4 hours) in order to control SMP and EPS fouling potential. The results presented also suggest that HRT reduction has a detrimental effect on performance and fouling. 相似文献
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To determine the removal efficiency of ultrafiltration (UF) membranes for nano-particles in the size range of viruses the state of the art uses challenge tests with virus-spiked water. This work focuses on bench-scale and semi-technical scale experiments. Different experimental parameters influencing the removal efficiency of the tested UF membrane modules were analyzed and evaluated for bench- and semi-technical scale experiments. Organic matter in the water matrix highly influenced the removal of the tested bacteriophages MS2 and phiX174. Less membrane fouling (low ΔTMP) led to a reduced phage reduction. Increased flux positively affected phage removal in natural waters. The tested bacteriophages MS2 and phiX174 revealed different removal properties. MS2, which is widely used as a model organism to determine virus removal efficiencies of membranes, mostly showed a better removal than phiX174 for the natural water qualities tested. It seems that MS2 is possibly a less conservative surrogate for human enteric virus removal than phiX174. In bench-scale experiments log removal values (LRV) for MS2 of 2.5-6.0 and of 2.5-4.5 for phiX174 were obtained for the examined range of parameters. Phage removal obtained with differently fabricated semi-technical modules was quite variable for comparable parameter settings, indicating that module fabrication can lead to differing results. Potting temperature and module size were identified as influencing factors. In conclusion, careful attention has to be paid to the choice of experimental settings and module potting when using bench-scale or semi-technical scale experiments for UF membrane challenge tests. 相似文献