给水厂生产废水回用对水质安全性的影响

给水厂生产废水直接回用可以改善混凝条件,但存在生物安全性的风险。通过微生物安全性及致畸致突变性的试验研究,认为在常规水处理工艺条件下,生产废水直接回用不会造成贾第鞭毛虫和隐孢子虫的累积以及出厂水的污染,没有增强水的致畸致突变性。     

污水再生处理过程中病原性原虫的去除特性研究

隐孢子虫和贾第鞭毛虫(简称“两虫”)是两种严重危害再生水水质安全的病原性原生动物。污水是病原性原虫的主要污染源,传统二级生物处理出水中的两虫浓度较高,深度处理工艺是去除两虫从而保障再生水水质安全的屏障。本文的目的是考察城市污水和再生水中两虫的污染现状,系统研究污水再生处理单元技术及典型工艺对两虫的去除特性,为客观评价污水再生利用的健康和生态风险,解决两虫污染问题提供理论依据。本研究首先针对国际上常用的两虫检测方法———1623方法中存在的成本高、回收率低等问题,对其各个环节进行系统的研究和优化,建立了适用于…     

隐孢子虫和贾第鞭毛虫的成套分析方法介绍

城市供排水系统中的隐孢子虫和贾第鞭毛虫直接威胁饮用水安全,同时对城市水环境带来生态和健康风险,因此对水体中的两虫进行调研,掌握其污染现状有重要意义。对两虫问题的系统研究离不开有效的检测手段,分别对两虫的密度检测、活性分析和种类鉴定方法进行了系统介绍,并对各种检测方法的优缺点进行说明和比较,进而提出了两虫的成套分析方法。     

饮用水微生物指标中的隐孢子虫和贾第鞭毛虫的检测

进入新的世纪，自来水为早日达到直饮标准，水质的要求不断提高，在国际和国内水质标准的各项指标中，由于一些微生物能在同一时间内造成大片人群发病或死亡的严重后果，一直倍受各方关注。水源中，除了我们已熟知的细菌外，隐孢子虫、贾第鞭毛虫也是普遍存在的微生物之一。但直至     

超声灭活水中贾第鞭毛虫影响因素及机理研究

采用超声(Ultrasonic,US)灭活水中贾第鞭毛虫,探讨了有机物、浊度及无机离子浓度对超声灭活的影响,并通过扫描电镜观察探究了超声灭活贾第鞭毛虫的机理。结果表明:超声灭活贾第鞭毛虫灭活率随腐殖酸浓度的增加而降低,当腐殖酸浓度为50.0 mg/L时灭活率降低至80.6%;在浊度0~20.0 NTU范围内,超声灭活贾第鞭毛虫的灭活率先升高后降低,当浊度为1.0 NTU时达到最佳灭活效果(98.6%);Ca2+,Zn2+和SO2-4对超声灭活贾第鞭毛虫的灭活率影响不明显,当Ca2+浓度为1.0 mg/L时,贾第鞭毛虫灭活率为96.3%,表明低浓度Ca2+对灭活略有促进作用;HCO-3浓度增加,贾第鞭毛虫灭活率下降,当HCO-3浓度为100 mg/L时灭活率下降至83.8%。扫描电镜形态学观察表明超声可以破坏贾第鞭毛虫细胞表面结构,可得出超声空化过程产生的机械剪切作用是超声灭活贾第鞭毛虫的主要原因。     

临江水厂扩建工程设计

上海市临江水厂原设计规模40万m3/d,规划供水量为60万m3/d。临江水厂扩建工程引进高效ACTIFLO澄清池,设计上升流速可达50m/h,并采用TGV双层滤料滤池,确保出厂水锰≤0.2mg/L。为达到《上海市供水专业规划》2010年水质目标,除采用臭氧活性炭处理工艺外,还采用了UV消毒工艺以去除隐孢子虫和贾第虫。另外为满足上海市环保要求,对60万m3/d规模水厂的排泥水进行了浓缩、脱水处置。     

重庆市主城给水厂邻苯二甲酸酯的研究

为了解邻苯二甲酸酯类对水质的污染情况,采用高效液相色谱法(HPLC)对重庆市主城6座给水厂的水源水和出厂水中5种邻苯二甲酸酯类化合物进行了研究.结果表明,邻苯二甲酸二甲酯、邻苯二甲酸二(2-乙基己基)酯和邻苯二甲酸二异辛酯在水源水和出厂水中均未检出,邻苯二甲酸二乙酯和邻苯二甲酸二丁酯在出厂水中未检出,但在水源水中有检出,其中以长江为水源水的邻苯二甲酸二丁酯含量为3.07～5.30 μg/L,以嘉陵江为水源水的邻苯二甲酸二丁酯含量为13.82～26.97 μg/L.对给水厂各工艺段的研究表明,经常规的混凝沉淀后,邻苯二甲酸二丁酯含量急剧降低,过滤、消毒对其影响不大.     

宁波市东钱湖水厂工艺设计

宁波市东钱湖水厂供水规模50万m3/d,现阶段要求出厂水浊度≤0.1NTU,pH不低于7.3,后期要求达到自来水直接饮用即符合《饮用净水水质标准》(CJ94—1999)的要求,且不得检出隐孢子虫和贾第虫,灭活率分别达到99%和99.9%。通过对其原水水质分析和对类似水厂的大量调查研究,提出采用常规水处理工艺并加强混凝、过滤等工程措施来满足现阶段出厂水水质要求,并建议后期根据原水水质变化情况和出厂水水质要求,增加臭氧-活性炭深度处理工艺。简要介绍了主要构建筑物工艺设计。包括设计参数、设备配置和加药消毒设施等,并对工艺设计特点进行了总结。     

臭氧-活性炭-超滤联用技术处理高寒地区微污染原水的工程应用

高寒地区Z水厂以L水库作为水源,近年来L水库水质变差,为轻度有机污染水体,原有常规处理工艺无法满足出厂水水质要求,出水CODMn最高值为6mg/L。通过采用臭氧-活性炭-超滤联用的升级改造技术,使水厂出水浊度小于0.05NTU,贾第鞭毛虫和隐孢子虫未检出,全面满足《生活饮用水卫生标准》(GB 5749-2006)的要求。     

国家游泳中心池水水质问题分析

国家游泳中心("水立方")是2008年第29届奥运会举行游泳、跳水等比赛的场所,游泳池水质标准的确定是选择其水处理工艺的关键。介绍了国家游泳中心游泳池水质标准确定的办法和依据,并就其中的消毒副产物THM、游泳池中微生物隐孢子虫和贾第鞭毛虫、水处理系统的选择、国外游泳池水质卫生动态等进行了分析。     

Evaluation of activated sludge treatment and the efficiency of the disinfection of Giardia species cysts and Cryptosporidium oocysts by UV at a sludge treatment plant in Campinas, south-east Brazil.

Among many waterborne diseases the giardiasis and cryptosporidiosis are of particular public health interest, because Giardia cysts and Cryptosporidium oocysts can persist for long periods in the environment, and both pathogenic protozoa have been implicated as the cause of many outbreaks of gastroenteritis in the last 25 years. In order to evaluate the efficiency of cysts and oocysts' removal by the activated sludge process, and by UV reactor in inactivating cysts and oocysts in one wastewater treatment plant (WWTP) of Campinas, three sampling points were selected for study: (1) influent, (2) treated effluent without UV disinfection and (3) treated effluent with UV disinfection. Giardia spp. cysts prevailed with higher density in the three different sample types. Cryptosporidium spp. oocysts were observed in only two samples of influent and just one sample of treated sewage with UV disinfection. In the animal infectivity assay for Giardia spp, one mouse of the UV treated group revealed trophozoites in intestinal scrapings. The results of the present study indicate that treatment by activated sludge process delivered a reduction of 98.9% of cysts and 99.7% of oocysts and UV disinfection was not completely efficient regarding the inactivation of Giardia cysts in the case of the WWTP studied.     

Determining potential indicators of Cryptosporidium oocysts throughout the wastewater treatment process

Most research on wastewater treatment efficiency compliance focuses on physicochemical and microbial indicators; however, very little emphasis has been placed so far on determining suitable indicator organisms to predict the discharge level of pathogens from treatment plants. In this study, raw wastewater, activated sludge, and the resulting final effluents and biosolids in four municipal wastewater treatment plants (WWTPs A, B, C and D) were seasonally investigated for human-virulent water-borne pathogens Cryptosporidium parvum/hominis and Giardia duodenalis, and microsporidia (e.g. Encephalitozoon hellem, E. intestinalis, and Enterocytozoon bieneusi) between 2008 and 2009. A suite of potential microbial indicators for human-virulent protozoa and microsporidia was also determined. A combination of multiple fluorescent in situ hybridization and immunofluorescent antibody assays were applied to detect Cryptosporidium oocysts, Giardia cysts, and microsporidian spores. Escherichia coli, enterococci and Clostridium perfringens spores were cultivated in selective media. Positive correlations were found between the abundance of enterococci and E. coli and abundance of Cryptosporidium oocysts (r(s) > 0.47, p < 0.01) and Giardia cysts (r(s) > 0.44, p < 0.01) at WWTPs A-D. Cryptosporidium perfringens spores were positively correlated to Cryptosporidium oocysts (r(s) = 0.40, p < 0.01) and Giardia cysts (r(s) = 0.46, p < 0.01). There was a strong positive correlation between abundance of Giardia cysts and that of Cryptosporidium oocysts (r(s) > 0.89, p < 0.01). To sum up, a suite of faecal indicator bacteria can be used as indicators for the presence of Cryptosporidium oocysts and Giardia cysts in these activated-sludge systems (WWTPs A, B and C). Overall, Giardia duodenalis was noted to be the best Cryptosporidium indicator for human health in the community-based influent wastewater and throughout the treatment process.     

Aerobic bacterial spores as process indicators for protozoa cysts in water treatment plants.

The possibility of using aerobic spores as indicators (surrogates) of water treatment efficiency for the removal of Giardia cysts and Cryptosporidium oocysts was evaluated in a water treatment plant that supplies the Barcelona area of Spain. The water treatment consists of pre-chlorination, flocculation-sedimentation, double filtration (sand and granular activated carbon, GAC) with intermediate ozonation and post-chlorination. Aerobic spores significantly increased after GAC filtration, which indicated an active propagation of aerobic spore-formers. However, anaerobic (Clostridium) spores could be a good surrogate for Cryptosporidium oocysts, especially if their detection in samples at low concentrations was improved.     

Occurrence and persistence of bacterial and viral faecal indicators in wastewater biofilms.

Biofilms within wastewater treatment plants can capture enteric microorganisms initially present in the water phase immobilising them either definitively or temporarily. Consequently, fates of microorganisms may totally change depending on whether they interact or not with biofilms. In this study, we assessed the stability of wastewater biofilms comparing the evolution of the concentrations of bacteria (heterotrophic plate count [HPC], thermotolerant coliforms [TC]) and viral (somatic coliphages [SC] and F-specific phages [F +]) indicators in the biofilms and in the corresponding wastewaters at 4 and 20 dgrees C. Additionally, we assessed the monthly occurrence of these bacterial and viral indicators as well as of pathogenic protozoa (Cryptosporidium oocysts and Giardia cysts) in three native wastewater biofilms for four months. Our results show that viral indicators (SC and F + ) persist longer in biofilms than in the corresponding wastewaters at 4 degrees C as well as at 20 degrees C. In contrast, persistence of bacterial indicators (TC and HPC) depends on both the temperature and the matrix. Differences between viral and bacterial persistence are discussed. Monthly analysis of native wastewater biofilms shows that bacterial and viral indicators, as well as Cryptosporidium oocysts and Giardia cysts, attach to wastewater biofilms to a concentration that remains stable in time, probably as a result of a dynamic equilibrium between attachment and detachment processes.     

Quantification and genotyping of Cryptosporidium spp. in river water by quenching probe PCR and denaturing gradient gel electrophoresis.

A new detection method was developed for the simultaneous quantification and genotyping of Cryptosporidium spp. in river water. Several modifications made to the US EPA Method 1623 enabled high and stable recovery of Cryptosporidium from 40 L of river water (geometric mean = 35%, standard deviation = 8.7%). Quenching probe PCR (QProbe PCR) was used to quantify the 18S rRNA gene of Cryptosporidium spp. This method could successfully detect single oocysts in a sample, and the lower quantitation limit was as low as 2.5 oocysts/sample. In addition, denaturing gradient gel electrophoresis (DGGE) followed by DNA sequencing was used to identify the genotypes. These methods were applied to detect Cryptosporidium spp. in the Koyama River, Japan. The positive ratio was 69% (11/16) with the maximum concentration of 59 oocysts/100 L. Seven genotypes including two novel ones were identified. These results showed that this detection method could provide valuable information on Cryptosporidium in river water, both in the concentration and in the genotypes, which is essential for the precise assessment of waterborne risk to human health.     

Giardia and Cryptosporidium in source waters of S?o Paulo State, Brazil.

Giardia lamblia and Cryptosporidium parvum are two protozoan intestinal parasites responsible for many drinking-water-related disease outbreaks in recent years. They are very resistant to conventional water treatment processes, can persist for long times in the environment and are, therefore, of great concern for public health. This work aimed to evaluate the presence of Giardia and Cryptosporidium in water sources from S?o Paulo State, Brazil, as part of the "Evaluation of Inland Waters from S?o Paulo State" project from CETESB. Over a period of 19 months, 278 water samples from 28 sites located in 10 watersheds were analysed. The immunofluorescence assay was used after concentration of the samples by the calcium carbonate flocculation technique. Thermotolerant (faecal) coliforms, faecal streptococci and Clostridium perfringens were also determined in order to verify the existence of correlation between these bacterial indicators and the protozoa. Giardia and Cryptosporidium were detected in 27% and 2.5% of the samples, respectively, a lower figure compared with the results reported by other authors, especially for Cryptosporidium. A Spearman rank correlation test demonstrated a significant correlation between Giardia and faecal indicator concentrations. According to the American Regulation of Monitoring (ICR), treated water from 16 of these 28 collection sites should also be analysed to evaluate whether the treatment process could remove the parasites. Some technical deficiencies of these methods still limit the utilisation of the monitoring results for public health decisions, but the data here reported will help to improve the quality of drinking water in S?o Paulo State.     

Genotyping of single Cryptosporidium oocysts isolated from sewage and river water.

The study was designed to genotype individual Cryptosporidium oocysts using an 18S rRNA gene-based semi-nested PCR and direct sequencing procedure. Positive PCR amplification was observed in all single C. parvum HNJ-1 oocyst samples tested. Semi-nested PCR and direct sequencing was applied to Cryptosporidium oocysts isolated from sewage and river water. The procedure could genotype 54% of FITC-stained single oocysts isolated from sewage and 32% from river water. The predominant genotype in both sewage and river water was C. parvum genotype 1, accounting for 33 and 25%, respectively, of all the FITC-stained intact Cryptosporidium oocysts present.     

Inactivation of enteric microbes in water by electro-chemical oxidant from brine (NaCl) and free chlorine.

Oxidant solutions of mostly free chlorine can be electrochemically produced on-site from brine (NaCl) solution and used to disinfect water at the household or community level. In this study electrochemical oxidant (ECO) from brine and free chlorine were evaluated under laboratory conditions for inactivation of test microbes. Purified suspensions of Escherichia coli, the rugose strain of Vibrio cholerae, Clostridium perfringens spores, MS2 coliphage and Cryptosporidium parvum oocysts were treated with 2 mg/L or 5 mg/L solutions of ECO or free chlorine at 5 degrees C and 25 degrees C and pH 6, 8, and 10 (pH 7 and 25 degrees C only for C. parvum oocysts) for contact times <60 min. Under nearly all conditions, inactivation kinetics were more rapid for E. coli, V. cholerae, C. perfringens spores and MS2 coliphage with ECO than with free chlorine. ECO reduced E. coli, V. cholerae and MS2 by >4 log10 within 30 min and C. perfringens spores by >2 log10 within 10 min at pH 8 and 25 degrees C. Contrary to previous results, however, C. parvum oocysts were not inactivated by ECO, and the reasons for this difference are uncertain. The on-site electrolytic generation of oxidants from brine provided a convenient and inexpensive disinfectant containing free chlorine that was effective against many enteric microbes, for the treatment of household and community drinking-water supplies worldwide. However, the effectiveness of such oxidants for inactivating C. parvum oocysts was variable and sometimes ineffective.     

Evidence for the existence of Cryptosporidium oocysts as single entities in surface runoff.

There is uncertainty whether Cryptosporidium oocysts attach to particles or to each other under ambient water conditions. Particle size distributions of Cryptosporidium oocyst suspensions were determined over a range of ionic strengths and pHs to determine under those environmental conditions that may promote oocyst aggregation. Cryptosporidium oocysts were shown to only aggregate in high ionic strength solutions (>0.45 M) and remain largely as single entities at ionic strengths and pHs that were likely to be encountered in surface runoff. Similarly, in loam soil suspensions, rather than attaching to the soil particles the majority of oocysts also remained as single entities. Overall, oocysts are expected to remain largely unattached to either themselves or soil particles in overland runoff. This has implications for pathogen transport and modelling since oocysts that are freely suspended are more likely to be transported in runoff to surface waters than if attached to more dense soil/faecal particles.     

长江南京段六大饮用水水源地水质变化及原因

对长江南京段六大水厂饮用水水源地的水质变化趋势进行评价,并对水质较差的饮用水水源地的污染原因进行分析。结果表明:①上元门水厂取水口所属水功能区水质最差,其次是远古水业、浦口水厂的水源地水质。长江南京大厂工业、渔业用水区(左岸),长江南京浦口饮用、渔业用水区(左岸),长江南京上元门燕子矶饮用水水源、渔业用水区(右岸)这3处水源地2008年以来水质较往年明显降低。②造成饮用水水源地水质恶化的污染源主要包括排涝泵站、工业企业排污和污水处理厂不达标排污。③总磷是六大水厂饮用水水源地主要污染因子之一,其对饮用水水源地的水质影响权重越来越大。