Inactivation of particle-associated viral surrogates by ultraviolet light

This study investigated whether colloid-sized particles can enmesh and protect viruses from 254-nm ultraviolet (UV) light and sought to determine the particle characteristics (e.g. size, chemical composition) that are most relevant in causing a protective effect. Two viral surrogates (MS2 coliphage and bacteriophage T4), three types of particles (kaolin clay, humic acid powder, and activated sludge), two coagulants (alum and ferric chloride), two filtration conditions (none and 0.45 microm), and two UV doses (40 and 80 mJ/cm2 for MS2 coliphage; 2 and 7 mJ/cm2 for bacteriophage T4) were considered in a series of bench-scale UV collimated beam experiments. Transmission electron microscopy was used to qualitatively confirm the phage particle-association after coagulation. Humic acid and activated sludge floc particles shielded both viral surrogates to a statistically significant degree (with >99% confidence) relative to particle-free control conditions, while the kaolin clay particles provided no significant protection. The results of the study suggest that particles <2 microm in diameter are large enough to protect viruses from UV light and that particulate chemical composition (e.g. UV-absorbing organic content) may be a critical factor in the survival of particle-associated viruses during UV disinfection.     

超滤膜处理净水厂沉淀池出水的中试研究

采用中试规模的内压式超滤膜系统处理水厂沉淀池出水,考察超滤膜系统长期运行的出水水质情况。结果表明,超滤膜系统在处理不同水质期沉淀池出水时具有较高的除浊率,平均除浊率达到93.4%,且99.4%的出水浊度<0.1 NTU,去除效果明显优于同期传统的滤池工艺。超滤膜系统对沉淀池出水中有机物的去除效果有限,对CODMn和UV254的平均去除率分别为17.2%和8.2%,出水CODMn≤2.0 mg/L的保证率在98%以上,膜出水CODMn浓度受进水水质和运行条件的影响不大。膜进水中以小分子质量有机物为主,在MW<1 ku区间内的DOC和UV254占到整体有机物含量的57.3%和53.5%。超滤膜系统对微生物的去除效果良好,膜出水水质大部分时间无需经过消毒就能保证卫生要求,可降低后续消毒的加氯量,从而减少消毒副产物的生成量。     

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％。     

Characterization of effluent water qualities from satellite membrane bioreactor facilities

Membrane bioreactors (MBRs) are often a preferred treatment technology for satellite water recycling facilities since they produce consistent effluent water quality with a small footprint and require little or no supervision. While the water quality produced from centralized MBRs has been widely reported, there is no study in the literature addressing the effluent quality from a broad range of satellite facilities. Thus, a study was conducted to characterize effluent water qualities produced by satellite MBRs with respect to organic, inorganic, physical and microbial parameters. Results from sampling 38 satellite MBR facilities across the U.S. demonstrated that 90% of these facilities produced nitrified (NH₄-N <0.4 mg/L-N) effluents that have low organic carbon (TOC <8.1 mg/L), turbidities of <0.7 NTU, total coliform bacterial concentrations <100 CFU/100 mL and indigenous MS-2 bacteriophage concentrations <21 PFU/100 mL. Multiple sampling events from selected satellite facilities demonstrated process capability to consistently produce effluent with low concentrations of ammonia, TOC and turbidity. UV-254 transmittance values varied substantially during multiple sampling events indicating a need for attention in designing downstream UV disinfection systems. Although enteroviruses, rotaviruses and hepatitis A viruses (HAV) were absent in all samples, adenoviruses were detected in effluents of all nine MBR facilities sampled. The presence of Giardia cysts in filtrate samples of two of nine MBR facilities sampled demonstrated the need for an appropriate disinfection process at these facilities.     

活性炭与超滤组合工艺深度处理饮用水

在北京燕山石化总厂利用活性炭吸附与超滤膜组合系统进行了为期一年的饮用水深度净化中试研究。结果表明，该系统能有效地去除水中的浊度，高锰酸盐指数，UV254和大肠杆菌。尤其是淹没式超滤膜组件有效地减少了出水中腐殖酸和富敏酸含量，其去除率平均为40％，从而有效减少了消毒副产物量。     

臭氧—固定化生物活性炭工艺深度处理饮用水

考察了以臭氧-固定化生物活性炭(O3-IBAC)工艺为核心的SY-1直饮水系统对微污染饮用水的净化效能.结果表明,在进水CODMn、DOC和浊度分别为3.0-5.8mg/L、3.54～6.35 mg/L和1.10-4.70NTU时,出水CODMn、DOC和浊度基本保持在1.5mg/L、1.3 mg/L和0.5 NTU以下;进水中检出38种有机物,而出水中仅检出15种.     

吸附架桥机理主导下APAM的多级絮凝效能

对吸附架桥机理主导下阴离子聚丙烯酰胺(APAM)的絮凝过程进行了研究,通过改变絮凝剂投加工况,对比分析常规絮凝与多级絮凝在污染物去除效果、絮体性能、絮体生长动力学与污泥调理能耗等方面的差异。结果表明,相同投药量下,两级絮凝的出水浊度低于三级絮凝和常规絮凝,两级絮凝在最少的APAM投加量(2 mg/L)下达到最低的出水浊度(19.53 NTU);与常规絮凝相比,两级絮凝的絮体成长速率、平均粒径和沉降速率分别增加12.67%、30μm、36.74%。两级絮凝在投加间隔为240 s、投配比为1∶1条件下絮凝效能最优,出水浊度为15.34 NTU,絮体沉降速率为1.1 NTU/s,絮体密度达到1.123 4 g/cm³。絮体破碎再絮凝过程中,两级絮凝与常规絮凝破碎后均能恢复至破碎前水平,但破碎后均出现不可逆的絮体结构破损,粒径在0~100μm的絮体颗粒增多,粒径>400μm的絮体减少,破碎后两级絮凝的絮体强度因子(68.15%)高于常规絮凝(41.63%),两级絮凝的絮体强度和抗破碎剪切能力更高。在剩余污泥调理方面,两级絮凝产生的污泥只需要投加40mg/L的APAM就可以达到最低的滤饼含水率(75.5%)。因此,两级絮凝可以显著提升除浊效能与絮体性能,是强化絮凝的发展方向。     

改性砂高速过滤技术用于污水再生回用的研究

采用SJ材料作为改性剂对石英砂滤料进行改性,经测定,其表面的物理化学性能优于石英砂.将改性砂应用于煤砂双层滤料高速过滤工艺,并处理某污水厂的二级出水,其出水的平均浊度、COD、UV254、PO43--P分别为1.23 NTU、27.4 mg/L、0.133 5 cm-1、0.42 mg/L,对各项指标的去除率均高于石英砂滤料,且完全符合GB/T 18920-2002标准中的城市杂用水水质要求.研究发现,高速过滤工艺应该以自然条件下的最大滤速为起始滤速;污染物积累和滤层负压导致水中溶解气体的析出会减小有效过水断面面积,这是引起滤速衰减的主要原因.     

化学生物絮凝/悬浮填料床工艺出水深度处理研究

化学生物絮凝/悬浮填料床是一种新型、高效的组合工艺,中试结果表明其出水TP为0.89 mg/L、浊度为9.7 NTU、氨氮为8.8 mg/L、COD为37.3 mg/L.采用流砂微絮凝过滤工艺、复合二氧化氯消毒对其出水进行了深度处理的试验研究,运行结果表明：在微絮凝剂PAFC投量为3.1 mg/L的条件下,出水TP、氨氮和COD浓度分别下降到0.38、7.2和26.6 mg/L,浊度也降至2.2NTU;当复合二氧化氯消毒接触时间≥30 min、游离余氯＞0.5 mg/L时,消毒后出水总大肠菌群≤3CFU/L.该系统维护简单、运行稳定,出水水质优良,各项指标均达到国家〈生活杂用水水质标准〉（CJ/T 48-1999）.     

Inactivation of indigenous coliform bacteria in unfiltered surface water by ultraviolet light

This study examined the potential for naturally occurring particles to protect indigenous coliform from ultraviolet (UV) disinfection in four surface waters. Tailing in the UV dose-response curve of the bacteria was observed in 3 of the 4 water samples after 1.3-2.6-log of log-linear inactivation, implying particle-related protection. The impact of particles was confirmed by comparing coliform UV inactivation data for parallel filtered (11 microm pore-size nylon filters) and unfiltered surface water. In samples from the Grand River (UVT: 65%/cm; 5.4 nephelometric turbidity units (NTU)) and the Rideau Canal (UVT: 60%/cm; 0.84 NTU), a limit of approximately 2.5 log inactivation was achieved in the unfiltered samples for a UV dose of 20 mJ/cm2 while both the filtered samples exhibited >3.4-log inactivation of indigenous coliform bacteria. The results suggest that particles as small as 11 microm, naturally found in surface water with low turbidity (<3NTU), are able to harbor indigenous coliform bacteria and offer protection from low-pressure UV light.     

双膜法在防伪纸生产废水深度处理与回用中的应用

针对防伪纸厂废水处理站的二沉池出水,采用中试规模的连续膜过滤(CMF)/反渗透(RO)集成工艺进行深度处理,以期能够满足回用的要求.结果表明,超滤膜有较强的抗污染能力,其过滤出水浊度<0.5 NTU,SS值基本为零,SDI值<3,完全能够满足RO的进水要求;RO产水COD平均为1.7 mg/L,电导率为10 μS/cm,满足防伪纸生产工艺回用水质的要求.采用双膜法深度处理防伪纸生产废水并回用具有工程可行性.     

含炭高密度沉淀池/超滤工艺处理污水厂二级出水

采用含炭高密度沉淀池/超滤组合工艺处理污水厂二级出水,考察了其对常规指标和微量有机污染物的去除效能,并对膜污染特性进行了分析。结果表明,组合工艺对浊度的去除率高达99.9%,出水浊度在0.01 NTU左右;对DOC、UV(254)、TP、氨氮和TN的平均去除率分别为41.02%、49.82%、60.44%、23.34%和10.90%;三维荧光光谱分析表明,组合工艺能有效去除水中的腐殖质和蛋白质类有机物;通过LC-MS/MS检测水中微量有机污染物发现,组合工艺可以使水中的微量有机污染物含量下降66%以上;同时含炭高密度沉淀池预处理能有效减轻膜污染,使跨膜压差增长速度减缓。     

Bacterial, viral and turbidity removal by intermittent slow sand filtration for household use in developing countries: experimental investigation and modeling

A two-factor three-block experimental design was developed to permit rigorous evaluation and modeling of the main effects and interactions of sand size (d₁₀ of 0.17 and 0.52 mm) and hydraulic head (10, 20, and 30 cm) on removal of fecal coliform (FC) bacteria, MS2 bacteriophage virus, and turbidity, under two batch operating modes (‘long’ and ‘short’) in intermittent slow sand filters (ISSFs). Long operation involved an overnight pause time between feeding of two successive 20 L batches (16 h average batch residence time (RT)). Short operation involved no pause between two 20 L batch feeds (5 h average batch RT). Conditions tested were representative of those encountered in developing country field settings. Over a ten week period, the 18 experimental filters were fed river water augmented with wastewater (influent turbidity of 5.4-58.6 NTU) and maintained with the wet harrowing method. Linear mixed modeling allowed systematic estimates of the independent marginal effects of each independent variable on each performance outcome of interest while controlling for the effects of variations in a batch’s actual residence time, days since maintenance, and influent turbidity. This is the first study in which simultaneous measurement of bacteria, viruses and turbidity removal at the batch level over an extended duration has been undertaken with a large number of replicate units to permit rigorous modeling of ISSF performance variability within and across a range of likely filter design configurations and operating conditions.On average, the experimental filters removed 1.40 log fecal coliform CFU (SD 0.40 log, N = 249), 0.54 log MS2 PFU (SD 0.42 log, N = 245) and 89.0 percent turbidity (SD 6.9 percent, N = 263). Effluent turbidity averaged 1.24 NTU (SD 0.53 NTU, N = 263) and always remained below 3 NTU. Under the best performing design configuration and operating mode (fine sand, 10 cm head, long operation, initial HLR of 0.01-0.03 m/h), mean 1.82 log removal of bacteria (98.5%) and mean 0.94 log removal of MS2 viruses (88.5%) were achieved.Results point to new recommendations regarding filter design, manufacture, and operation for implementing ISSFs in local settings in developing countries. Sand size emerged as a critical design factor on performance. A single layer of river sand used in this investigation demonstrated removals comparable to those reported for 2 layers of crushed sand. Pause time and increased residence time each emerged as highly beneficial for improving removal performance on all four outcomes. A relatively large and significant negative effect of influent turbidity on MS2 viral removal in the ISSF was measured in parallel with a much smaller weaker positive effect of influent turbidity on FC bacterial removal. Disturbance of the schmutzdecke by wet harrowing showed no effect on virus removal and a modest reductive effect on the bacterial and turbidity removal as measured 7 days or more after the disturbance. For existing coarse sand ISSFs, this research indicates that a reduction in batch feed volume, effectively reducing the operating head and increasing the pore:batch volume ratio, could improve their removal performance by increasing batch residence time.     

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。     

印染废水深度处理工程及工艺改进

采用曝气生物滤池(BAF)/臭氧预氧化/BAF组合工艺对印染废水二级生化处理出水进行深度处理,COD从进水的90～160 mg/L左右稳定降至30 mg/L以下,色度从进水的64～128倍左右降至2～4倍,出水浊度<1 NTU,排放水质达到回用要求,处理成本为1.43元/m~3.之后又对工艺进行改进,设计出一体化装置,COD去除率>70%,其他指标均达到排放标准,处理成本仅为0.89元/m~3.     

强化活性炭滤池过滤性能的试验研究

采用在活性炭滤池前端投加不同药剂的方法深度净化某水厂沉淀池出水,考察了不同滤池形式、聚合氯化铝(PAC)投加量和阳离子型聚丙烯酰胺(PAM)投加量对沉后水浊度的去除效果。结果表明,在下向流滤池前端投加0.3 mg/L的PAC和0.03 mg/L的PAM可以明显强化活性炭滤池的过滤效果,使出水浊度小于0.1 NTU;与砂滤池出水相比,活性炭滤池对浊度的去除率提高了16.6%,CODMn去除率提高了56%;相应的滤池水头损失增加较快,但仍可以满足运行周期不小于24 h的设计要求;滤后水中铝和溴酸盐含量均满足《生活饮用水卫生标准》(GB 5749—2006)要求。     

新河水厂双阀滤池的技术改造

介绍了新河水厂对运行多年的双阀滤池所进行的技术改造,包括配水系统和自动控制系统的改造方案、相关设备的选择、滤池土建施工的要求和方法以及滤池的调试。改造后的运行结果表明,在滤前浊度提高的前提下,滤池出水浊度明显下降,低于0.4 NTU;滤池运行周期平均提高了12 h。改造后的滤池运行稳定,实现了自动化控制。     

循环造粒流化床处理水厂排泥水的试验研究

以西安市某自来水厂的沉淀池排泥水为处理对象,采用循环造粒流化床技术先进行工艺参数优化中试,再进行生产性试验研究。中试结果表明,循环造粒流化床的运行稳定性较高,即使进水浊度在200~800 NTU范围内变化或进水上升流速在25~70 cm/min之间变化,出水浊度仍可稳定保持在10 NTU以下;工艺优化参数如下:上升流速为70 cm/min,搅拌转速为5~8 r/min,助凝剂聚丙烯酰胺(PAM)投加量为4~5 mg/L。在中试的基础上进行生产性试验,出水浊度始终稳定在10 NTU以下,最佳间歇排泥间隔为4 h,出泥含水率为95.8%,处理成本为0.1元/m^3。中试及生产性试验结果表明,采用循环造粒流化床处理排泥水,具有出水水质好、抗冲击负荷能力强、污泥浓缩效果好、处理成本低等优点。     

多孔超滤膜深度处理黄河水的研究

考察了Filcore七孔超滤膜深度处理黄河水的效能。结果表明,经过3个月的中试,膜组件运行稳定,在产水量为4.2 m3/h、进水浊度约为4 NTU的条件下,七孔超滤膜的出水浊度基本在0.2 NTU以下,出水SDI值基本在1.2以下,跨膜压差保持在0.02 MPa左右,膜通量为84 L/(m2.h),产水率达91.7%以上,且电耗和药耗都较低(电耗仅为0.103 kW.h/m3),膜组件未出现气泡、断丝等现象。由此可知,Filcore七孔超滤膜具有良好的抗污染性和透水性,且膜丝的机械强度较高,出水水质满足反渗透的进水要求,用于黄河水的深度处理是可行的。     

MBR和UF深度处理石化废水的比较研究

为给某石化企业的反渗透（RO）系统提供水质良好且稳定的进水，分别采用膜生物反应器（MBR）和超滤（UF）工艺对该厂二沉池出水进行了深度处理试验，考察了进、出水的浊度及COD、SDI等指标。结果表明：UF系统的出水浊度平均为0．18NTU，COD平均为22．1mg／L，SDI平均为2．50；MBR系统的出水浊度平均为0．14NTU，COD平均为20．1mg／L，SDI平均为2．22。MBR的出水水质比UF更稳定，且具有较强的耐冲击负荷能力。