臭氧-生物活性炭对微絮凝强化过滤的影响研究

嘉兴市某水厂采用臭氧-生物活性炭结合微絮凝强化过滤工艺,实现了出水浊度和2μm以上颗粒数分别稳定在0.1 NTU和30个/m L以下的良好效果。结合该水厂的净水工艺,考察了臭氧-生物活性炭工艺对微絮凝强化过滤工艺的影响。结果表明,臭氧-生物活性炭工艺去除了大量有机物,影响了胶体的稳定性,有利于微絮凝强化过滤工艺对浊度与颗粒物的去除。臭氧-生物活性炭工艺出水Zeta电位处于-5~0 m V范围内,粒径为5~20μm的大颗粒数量减少、粒径为2~5μm的小颗粒数量上升,总颗粒数和浊度上升,经微絮凝和砂滤池处理后,Zeta电位进一步上升直至接近于零,水中颗粒物与浊度被大幅去除。     

在线颗粒计数仪在自来水厂水质监控中的应用

利用在线颗粒计数仪和在线浊度仪对超低浊度(0.5 NTU以下)进水的砂滤池运行情况进行了在线监控研究。结果表明,反冲洗结束后10 min内,滤池出水浊度可降至0.1 NTU以下,粒径2μm的颗粒物总数可降至50个/mL以下;稳定运行后,滤池出水浊度维持在0.05 NTU以下,粒径2μm的颗粒物总数维持在30个/mL以下,滤池运行周期为48 h。当滤池出水水质发生波动时,在线颗粒计数仪比浊度仪的响应更迅速。在线颗粒数监测技术作为在线浊度监测技术的补充,可以有效提高出水的生物安全性,保障饮用水安全,为自来水厂的运行管理提供强有力的技术支撑。     

混凝/砂滤/超滤组合工艺对水中颗粒物质的去除

主要研究了混凝/砂滤/超滤组合工艺对水中颗粒物的去除效果.试验结果表明:该工艺可有效去除水中浊度及颗粒物,膜出水浊度低于0.2NTU,水中粒径大于2μm的颗粒数量少于20个/mL.     

梅林水厂臭氧/生物活性炭工艺的运行效果

系统深入地研究了深圳市梅林水厂臭氧/生物活性炭工艺的运行效果,结果表明：①该工艺可有效去除常规工艺出水中的浊度和颗粒物,对浊度的平均去除率为24%（相对于砂滤出水）,生物活性炭滤池出水的浊度＜0.10 NTU,粒径＞2μm的颗粒数可以降低到50个/mL.②对色度及嗅味的去除效果显著,出厂水的色度可以稳定保持在5倍以下;通常情况下,出厂水的嗅阈值＜10,远低于砂滤出水的100.③对CODMn、UV254和TOC的去除效果较理想.经过主臭氧段后AOC浓度增加较多,但经过活性炭处理后又大幅降低,确保了出厂水的生物稳定性.④生物活性炭滤池出水中的细菌数大多数情况下低于主臭氧段出水,但是在某些情况下也会突然增加.⑤臭氧/生物活性炭工艺对贾第虫和隐孢子虫的去除效果明显.⑥活性炭上的生物量随着滤层深度的增加而减少,生物膜的生长会受水温、余臭氧浓度和反冲洗等因素的影响.⑦活性炭的吸附性能如碘值和亚甲兰值,会随着运行时间的延长而逐渐降低.⑧臭氧/生物活性炭工艺运行后增加制水成本约0.106元/m^3.     

三种典型砂滤池过滤参数优化及过滤性能对比

通过研究国内外三种典型石英砂滤池的出水浊度、颗粒数以及水头损失,对比分析了不同滤速条件下三种滤池的过滤性能,以期达到优化过滤参数及优选滤料的目的。结果表明,水头损失是各滤池过滤周期的主要限制因素,同等条件下美国级配滤料滤池的水头损失增长速率最大,其次是国内级配滤料滤池、国内均质滤料滤池;不同滤速条件下各滤池的出水浊度均保持稳定,国内级配滤料滤池出水浊度在过滤周期末段有上升趋势;出水中颗粒数随着滤速的增加而增大,增大滤速会降低滤池对小颗粒的截留效率,国内均质滤料滤池出水的颗粒含量最低,其次是国内级配滤料滤池、美国级配滤料滤池,各滤池对粒径为3~5μm的颗粒物去除效果最差。综合各因素,国内均质滤料滤池的过滤性能最佳,其次是国内级配滤料滤池、美国级配滤料滤池,三者的最佳滤速分别为(6~7)、8、4 m/h。     

三种深度处理工艺出水的微生物安全性比较

分别从浊度、颗粒数、细菌总数、HPC和浮游动物等方面进行研究,探讨了炭砂倒置工艺、炭砂滤池以及炭砂滤池/超滤复合工艺等三种给水深度处理技术对微生物安全性的保障作用。结果表明,炭砂滤池/超滤复合工艺对微生物的安全保障能力大大高于其他两种工艺。炭砂滤池/超滤复合工艺的出水水质非常稳定,浊度一般为0.01～0.03 NTU左右,平均为0.022 NTU,粒径2μm的颗粒数10个/mL;而其他两种工艺的出水浊度一般在0.1 NTU左右,颗粒数一般为几十至几百个/mL,且水质波动较大。炭砂过滤和炭砂倒置等两工艺出水的细菌总数和HPC均较高,存在一定的微生物风险;炭砂倒置工艺中的砂滤对降低微生物数量起到重要作用;复合工艺出水的细菌总数和HPC均很低。浮游动物能穿透炭砂滤层而出现在出水中;炭砂倒置工艺出水中的浮游动物数量有较大下降;复合工艺对浮游动物的截留效果非常好,出水中几乎不含浮游动物,只是偶尔检出数个轮虫。     

BAC滤池对浊度和颗粒数的控制研究

传统的贾第鞭毛虫和隐孢子虫（简称“两虫”）检测方法存在诸多不足，为此选用浊度和颗粒数作为“两虫”的替代指标，以对浊度和颗粒物的去除率来衡量生物活性炭（BAC）滤池对“两虫”的控制效果。试验结果表明：采用颗粒数表征滤后水水质比采用浊度更适宜。过滤初期颗粒数从峰值降到50个／mL以下所需的时间比浊度降到0．1NTU所需的时间多1h左右。正常过滤期间BAC滤池进水浊度一般在0．1NTU以下，经过BAC滤池处理后，浊度得到进一步降低，平均去除率为52．7％。炭层对浊度的去除率为56．4％，其出水浊度基本上都低于0．05NTU，而砂层对浊度不但没有去除能力，反而使出水浊度平均上升了约3．7％。炭层对颗粒物的平均去除率为33．3％，砂层对颗粒物的平均去除率为8．5％。     

臭氧/生物活性炭工艺的微生物泄漏控制研究

臭氧/生物活性炭工艺在广泛应用并取得良好效果的同时也存在一定的微生物泄漏风险,并且活性炭工艺出水中的颗粒物会保护细菌,降低消毒工艺的灭活效率。研究了臭氧/生物活性炭工艺工况的改变对出水中异养菌和颗粒物数量的影响,并通过炭后水的消毒试验,确定能够保障出水水质生物安全性的消毒剂量及适宜的颗粒数控制水平。投加臭氧对臭氧/生物活性炭工艺出水异养菌数量的影响甚微,但能够减少出水中颗粒物数量;在滤速为5~9 m/h范围内,改变滤速并没有影响出水中异养菌及颗粒物数量;当臭氧投加量为1 mg/L、滤速为7 m/h时,出水异养菌及颗粒物数量分别为10~(4.01)CFU/m L和86 CNT/m L。气水联合反冲洗能够更长时间地维持出水异养菌数和颗粒数分别在10~(4.05)CFU/m L和100 CNT/m L以下。当臭氧/生物活性炭工艺稳定运行时,炭后水中颗粒物数量在50~100 CNT/m L之间,此时1.5 mg/L的氯消毒剂浓度能够保障出水水质的生物安全性,并且颗粒物的存在会增加细菌抵抗消毒剂的能力,同时出水中颗粒物数量的增加也会降低消毒剂的灭活效率。当消毒剂投量为1.5 mg/L时,粒径2μm的颗粒物数量应控制在150 CNT/m L之内。     

颗粒物计数仪在生物活性炭工艺中的应用

应用颗粒物计数仪在线监测砂滤池和生物活性炭滤池出水，结果表明，其敏感度高，较浊度仪更能及时、准确地反映活性炭滤池运行过程中的出水水质变化，对优化滤池运行以及确保出水水质有着重要作用。     

微絮凝强化过滤在嘉兴贯泾港水厂的应用

嘉兴市贯泾港水厂通过将砂滤池设置于生物活性炭(BAC)滤池后,并采用微絮凝强化过滤等措施,实现了砂滤出水、出厂水浊度≤0.1 NTU,颗粒物数量≤30个/mL,有效控制了微生物风险.微絮凝强化过滤的聚氯化铝铁投加量为5～10 mg/L,增加药剂费用约0.005～0.01元/m3.该工艺存在的主要问题是砂滤池水头损失增长较快,过滤周期明显缩短.     

Optimization of the extended terminal subfluidization wash (ETSW) filter backwashing procedure

The increased passage of particles and microorganisms through granular media filters immediately following backwashing is a common problem known to the water treatment community as filter "ripening" or maturation. While several strategies have been developed over the years to reduce the impact of this vulnerable period of the filtration cycle on finished water quality, this research involves a recently developed filter backwashing strategy called the extended terminal subfluidization wash (ETSW). ETSW is a method of terminating the backwash cycle with a subfluidization wash for a period of time sufficient to pass one theoretical filter-volume of water upward through the filter. ETSW was shown to remove significantly greater quantities of backwash remnant particles thereby reducing the magnitude of filter ripening turbidity and particle count spikes. Optimum ETSW flow rates were determined for deep-bed anthracite and granular activated carbon filters herein by monitoring filter effluent turbidities and particle counts during the filter ripening period. Optimality of the coagulation process was also shown to influence the magnitude of filter ripening particle passage. ETSW was found to be equally effective for biological and conventional deep-bed anthracite filters.     

输配水系统中颗粒物与浊度演变特征研究

通过将颗粒物计数方法应用于城市输配水系统,研究分析了输配水系统中颗粒物数量与浊度的相关性以及其沿线变化规律.结果表明,随着水流方向,颗粒物数量有上升趋势;管网末梢颗粒物数量和浊度偏高;颗粒粒径越小,其含量越多;在一定范围内颗粒物数量和浊度有一定相关性;对颗粒物的研究比浊度更加准确和直观.此外,从颗粒物角度对水质进行特征分析,不仅为水质评价提供更多信息,还为颗粒物计数法的应用提供基础数据.     

磷渣粉的粒径分布与其活性的灰色关联分析

研究了磷渣粉比表面积对其胶凝活性的影响,运用灰色关联理论分析了其粒径分布与活性指数的关系。结果表明:粒径30.2μm以上的颗粒对磷渣粉的活性起削弱作用,粒径0.00~30.2μm的颗粒对其活性起增强作用。其中,粒径5.0~10.0μm颗粒的含量是影响磷渣粉7d活性指数A7的关键因子,粒径10.0~20.0μm颗粒的含量是影响28d活性指数A28的关键因子。为提高磷渣粉的胶凝活性,其比表面积不宜低于397m2·kg-1,同时,应尽可能提高磷渣中粒径为5.0~30.2μm,尤其是粒径5.0~20.0μm的颗粒含量,并减少或限制粒径大于30.2μm的颗粒含量。     

Fractional Aerosol Filtration Efficiency of In-Duct Ventilation Air Cleaners

The filtration efficiency of ventilation air cleaners is highly particle-size dependent over the 0.01 to 3 μm diameter size range. Current standardized test methods, which determine only overall efficiencies for ambient aerosol or other test aerosols, provide data of limited utility. Because particles in this range are respirable and can remain airborne for prolonged time periods, measurement of air cleaner fractional efficiency is required for application to indoor air quality issues. The objectives of this work have been to 1) develop a test apparatus and procedure to quantify the fractional filtration efficiency of air cleaners over the 0.01 to 3 μm diameter size range and 2) quantify the fractional efficiency of several induct air cleaners typical of those used in residential and office ventilation systems. Results show that efficiency is highly dependent on particle size, flow rate, and dust load present on the air cleaner. A minimum in efficiency was often observed in the 0.1 to 0.5 μm diameter size range. The presence of a dust load frequently increased an air cleaner's efficiency; however, some air cleaners showed little change or a decrease in efficiency with dust loading. The common furnace filter had fractional efficiency values of less than 10% over much of the measurement size range.     

石灰石粉粒度分布对水泥性能的影响

利用灰色关联分析方法研究了石灰石粉的粒度分布对水泥性能的影响.研究结果表明,5 ～11μm、0～5 μm的石灰石粉颗粒分别是水泥3d、28 d抗压强度的最强影响因子.0～23 μm的石灰石粉颗粒对3d、28 d强度起增进作用;石灰石粉颗粒＞23 μm时,水泥强度随着石灰石粉含量的增大而降低.因此,可以通过优化石灰石粉的粒度分布来改善水泥性能.     

电力外绝缘污秽颗粒等效模型和粒径分布探讨

为今后实现自然积污规律研究和防污的差异化,对污秽颗粒等效简化模型、大气总悬浮颗粒物(TSP)的粒径分布函数、绝缘表面污秽主要化学成分对应TSP的粒径分布进行了综述和分析,认为可以污秽颗粒可等效简化为球体,使用空气动力学粒径衡量其粒径;建立TSP粒径分布函数拟合模型;分析认为化学成分Ca2+、SO42-、Cl-、SiO2、Al2O3在TSP中的粒径主要分布在1.8~10μm,0~10μm,1.8~10μm,30-40μm,40μm~50μm的范围内,最后对自然积污规律研究和防污的差异化进行了展望。     

Particle size distribution in effluent of trickling filters and in humus tanks

Particles and aggregates from trickling filters must be eliminated from wastewater. Usually this happens through sedimentation in humus tanks. Investigations to characterize these solids by way of particle size measurements, image analysis and particle charge measurements (zeta potential) are made within the scope of Research Center for Science and Technology "Fundamentals of Aerobic biological wastewater treatment" (SFB 411). The particle size measuring results given within this report were obtained at the Ingolstadt wastewater treatment plant, Germany, which served as an example. They have been confirmed by similar results from other facilities. Particles flushed out from trickling filters will be partially destroyed on their way to the humus tank. A large amount of small particles is to be found there. On average 90% of the particles are smaller than 30 microm. Particle size plays a decisive role in the sedimentation behaviour of solids. Small particles need sedimentation times that cannot be provided in settling tanks. As a result they cause turbidity in the final effluent. Therefore quality of sewage discharge suffers, and there are hardly advantages of the fixed film reactor treatment compared to the activated sludge process regarding sedimentation behaviour.     

Characterization of indoor sources of fine and ultrafine particles: a study conducted in a full-scale chamber

Humans and their activities are known to generate considerable amounts of particulate matter indoors. Some of the activities are cooking, smoking and cleaning. In this study 13 different particle sources were for the first time examined in a 32 m3 full-scale chamber with an air change rate of 1.7 +/- 0.1/h. Two different instruments, a condensation particle counter (CPC) and an optical particle counter (OPC) were used to quantitatively determine ultrafine and fine particle emissions, respectively. The CPC measures particles from 0.02 microm to larger than 1.0 microm. The OPC was adjusted to measure particle concentrations in eight fractions between 0.3 and 1.0 microm. The sources were cigarette side-stream smoke, pure wax candles, scented candles, a vacuum cleaner, an air-freshener spray, a flat iron (with and without steam) on a cotton sheet, electric radiators, an electric stove, a gas stove, and frying meat. The cigarette burning, frying meat, air freshener spray and gas stove showed a particle size distribution that changed over time towards larger particles. In most of the experiments the maximum concentration was reached within a few minutes. Typically, the increase of the particle concentration immediately after activation of the source was more rapid than the decay of the concentration observed after deactivation of the source. The highest observed concentration of ultrafine particles was approximately 241,000 particles/cm3 and originated from the combustion of pure wax candles. The weakest generation of ultrafine particles (1.17 x 10(7) particles per second) was observed when ironing without steam on a cotton sheet, which resulted in a concentration of 550 particles/cm3 in the chamber air. The highest generation rate (1.47 x 10(10) particles per second) was observed in the radiator test. PRACTICAL IMPLICATIONS: Humans and their activities are known to generate substantial amounts of particulate matter indoors and potentially they can have a strong influence on short-term exposure. In this study a quantitative determination of the emissions of fine and ultrafine particles from different indoor sources was performed. The aim is a better understanding of the origin and fate of indoor particles. The results may be useful for Indoor Air Quality models.     

The impact of increased loading rate on granular media, rapid depth filtration of wastewater

The impact of loading rate on tertiary filtration of wastewater was studied using a pilot-scale, dual-media, rapid depth filtration system. Loading rates of 12.2, 15.3, 18.3, 21.4, and 24.4m/h were tested on parallel filter columns treating the same coagulated secondary wastewater to determine the impact on removal of turbidity, particles (2-15 microm), total coliform bacteria, Escherichia coli, and MS2 bacteriophage, as well as on the particle deposition profile in the filter bed. Increasing the loading rate from 12.2 to 24.4m/h decreased the removal efficiencies for all metrics. The observed impact of loading rate on particle removal was similar to that predicted by a clean-bed filtration model, although the model significantly underestimated the removal efficiencies of the smaller particles. For two loading rates, 12.2 and 18.3m/h, the effect of coagulant dose was also studied; the negative impact of loading rate on removal efficiency was eliminated by increasing the coagulant dose for the higher loading rate, which also resulted in removal of particles deeper in the filter bed. For all conditions studied, loading rate had no observable impact on the ability to disinfect filter effluents with chloramines. The results of this research indicate that loading rates higher than those typically used in tertiary filtration can produce acceptable effluent quality, and support a regulatory approach based on filter effluent turbidity.