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The applicability of next generation DNA sequencing (NGS) methods for water quality assessment has so far not been broadly investigated. This study set out to evaluate the potential of an NGS-based approach in a complex catchment with importance for drinking water abstraction. In this multi-compartment investigation, total bacterial communities in water, faeces, soil, and sediment samples were investigated by 454 pyrosequencing of bacterial 16S rRNA gene amplicons to assess the capabilities of this NGS method for (i) the development and evaluation of environmental molecular diagnostics, (ii) direct screening of the bulk bacterial communities, and (iii) the detection of faecal pollution in water. Results indicate that NGS methods can highlight potential target populations for diagnostics and will prove useful for the evaluation of existing and the development of novel DNA-based detection methods in the field of water microbiology. The used approach allowed unveiling of dominant bacterial populations but failed to detect populations with low abundances such as faecal indicators in surface waters. In combination with metadata, NGS data will also allow the identification of drivers of bacterial community composition during water treatment and distribution, highlighting the power of this approach for monitoring of bacterial regrowth and contamination in technical systems. [ABSTRACT FROM AUTHOR]

Hepatitis A virus (HAV) strains found in selected South African (SA) surface waters were characterised to establish what HAV types are circulating in the environment, thus reflecting circulation in the surrounding communities. Surface water samples used for irrigation or domestic purposes, and water samples from the outflow of wastewater plants were collected from six provinces. Viruses were recovered from the samples using a glass wool adsorption-elution method and then further concentrated using polyethylene glycol/sodium chloride precipitation. After automated nucleic acid extraction, samples were analysed for HAV by real-time reverse-transcriptase polymerase chain reaction. HAV strains were genotyped by nucleotide sequence analysis of the capsid gene VP1 and the VP1/P2B junction. HAVs were detected in 76% (16/21) of the surface water samples and in 37% (19/51) of the samples from the wastewater plants. Strains were characterised from 32 of the 35 samples and classified within genotype IB. The presence of genotype IB in the water sources confirms human faecal contamination. Hence, these faecally-contaminated water sources may be a potential transmission route of HAV infection and a potential source of contamination of irrigated fresh produce in SA. [ABSTRACT FROM AUTHOR]

Legislation in Sweden and the European Union concerning the use of sewage sludge in agriculture is under revision and future concentration limits for pathogens in treated sludge are likely to be expected. The aim of this study was to evaluate the hygienization of Salmonella, Escherichia coli, Enterococcus and Clostridium perfringens through continuous anaerobic digestion at 35, 55 or 60 °C, as well as to investigate process stability and methane production at 60 °C. The results indicated that digestion at 55 or 60 °C with a minimum exposure time of 2 h resulted in good reduction of Salmonella, E. coli and Enterococcus and that anaerobic digestion could thus be used to reach the concentration limits suggested for the EU, as well as Sweden. Furthermore, stable continuous anaerobic digestion of sludge was achieved at 60 °C, albeit with 10% less methane production compared to digestion at 35 and 55 °C. [ABSTRACT FROM AUTHOR]

In this study, a granular sludge sequencing batch reactor (GSBR) was started-up for the biological aerobic treatment of wastewater containing highly toxic 2,4-dichlorophenol (2,4-DCP), in presence of readily biodegradable sodium acetate (NaAc) as the growth substrate. Different influent concentrations of NaAc (420-800 mg/L) and 2,4-DCP (0-20 mg/L), as well as different operating conditions (i.e. cycle length), were tested in order to determine the optimal strategy for successful GSBR start-up: stable granulation and complete 2,4-DCP removal were achieved only when high NaAc influent concentration and volumetric organic loading rates (800 mg/L and 1.9 kgCOD/(m3.d), respectively), prolonged reaction phase (cycle time of 4 hours) and gradual increase of 2,4-DCP concentration in the influent were applied, thus providing useful information for process optimization in view of future scale-up. Granules were initially colonized by fungi which progressively disappeared during the start-up process, and complete 2,4-DCP removal was mostly due to bacterial activity, in particular Betaproteobacteria, as shown by fluorescence in situ hybridization (FISH). [ABSTRACT FROM AUTHOR]

The disinfection performance of three subsurface flow constructed wetlands (SSF), a free-water surface-constructed wetland and three ponds were investigated. They functioned as advanced treatment stage following treatment in a large municipal wastewater treatment plant equipped with nutrient removal. Despite low influent concentrations of 103.9/100 mL, Escherichia coli underwent a reduction of 1.7 (ditch) to 2.3 (sandy loamy SSF) orders of magnitude. After passing through these treatment plants E. coli was lowered sufficiently to within the permitted levels thus allowing it to be used in drip irrigation of fruits and vegetables. The change of seasons and hydraulic loading (in the range of 50-150 mm/day) as well as short-term overloadings did not impact the effluents' quality. [ABSTRACT FROM AUTHOR]

The shock effect, survival and ability of activated sludge to acclimatize to wastewater containing different concentrations of NaCl and Na2SO2 were investigated under laboratory conditions. To accomplish this, the potential penetration of a sewage system by seawater as a consequence of storm surge flooding was simulated. The experiments were conducted using activated sludge taken from the aeration tank of a communal wastewater treatment plant and adding different concentrations up to 40 g/L of NaCl and 4.33 g/L of Na2SO2. The effects of salinity on the activated sludge were monitored for 5 weeks based on the values of pH, dissolved oxygen, total suspended solids, volatile suspended solids, sludge volume, sludge volume index, electrokinetic potential, respirometric measurements and enzymatic activity. The addition of salt sharply reduced or completely inhibited the microbial activity in activated sludge. When salt concentrations were below 10 g/L NaCl, microorganisms were able to acclimatize in several weeks and achieve the same initial activity as in raw sludge samples. When the salt concentration was above 30 g/L NaCl, the acclimatization process was very slow or impossible. [ABSTRACT FROM AUTHOR]

Quantitative polymerase chain reaction (qPCR) offers a rapid, highly sensitive analytical alternative to the traditional culture-based techniques of microbial enumeration typically used in water quality monitoring. Before qPCR can be widely applied within surface water monitoring programs and stormwater assessment research, the relationships between microbial concentrations measured by qPCR and culture-based methods must be assessed across a range of water types. Previous studies investigating fecal indicator bacteria quantification using molecular and culture-based techniques have compared measures of total concentration, but have not examined particle-associated microorganisms, which may be more important from a transport perspective, particularly during the calibration of predictive water quality models for watershed management purposes. This study compared total, free-phase, and particle-associated Escherichia coli concentrations as determined by the Colilert defined substrate method and qPCR targeting the uidA gene in stream grab samples partitioned via a calibrated centrifugation technique. Free-phase concentrations detected through qPCR were significantly higher than those detected using Colilert although total concentrations were statistically equivalent, suggesting a source of analytical bias. Although a specimen processing complex was used to identify and correct for inhibition of the qPCR reaction, high particle concentrations may have resulted in underestimation of total cell counts, particularly at low concentrations. Regardless, qPCR-based techniques will likely have an important future role in stormwater assessment and management. [ABSTRACT FROM AUTHOR]

The study of various types of Pseudomonas aeruginosa strains isolated from water environments is of paramount importance from a public health point of view, due to their ubiquity and pathogenicity. Molecular (Random Amplified Polymorphic DNA and Pulsed Field Gel Electrophoresis) and phenotypical (serotyping) typing methods were applied to environmental P. aeruginosa strains. The typeability and discriminatory power of the methods were studied and compared. The two molecular methods managed to type a number of P. aeruginosa strains which were non-serotypeable due to their rough phenotypes. According to our results, the combination of phenotypic and genotypic methods increased the reliability of the results, yielding several different clones that seem to circulate in Greek water environments. [ABSTRACT FROM AUTHOR]

Directive 2000/60/EC requires the achievement of a 'good chemical status' for surface water within pre-established dates. Disinfection is needed to achieve compulsory final microbial limit values (in Italy for wastewater discharges the parameter Escherichia coli - EC - is imposed by law with a maximum limit value of 5,000 cfu/100 mL). Liquid waste and disinfection by-products must be considered when designing appropriate monitoring of dangerous substances; the specific classes of substances must be investigated according to the typology of received wastewaters and liquid wastes (where applicable) and specific analytical techniques, with Limit of Detection (LOD) lower than the limit values, must be applied; the difficulties faced by national and regional environmental control Agencies is that these techniques have to be applied during ordinary activity and not only for research purposes. The study aims to present the control of dangerous substances, as a screening view, in wastewater treatment plant (WWTP) discharges in the province of Venice (Northern Italy) for the period 2007-2010 based on available data from institutional controls. In addition, the wastewater disinfection process with ozone applied to a medium size WWTP (45,000 Population Equivalents) is presented as a case study, with a view to assessing the microbiological abatement efficacy and the presence of dangerous substances. Discharge quality of the WWTPs in the province of Venice presented mean values that were higher than the LOD, but only for certain metals. For the Paese plant, zinc and chloroform were the only micro-pollutants detected with a higher level than the LOD. From microbiological data in the period 2006-2011 the disinfection abatement efficiency for Paese was, in most cases above 99% for EC, faecal coliform (FC), faecal streptococci (FS) while efficiency was slightly lower for total coliform (TC); however, the proposed criterion aimed at respecting 99.99% abatement was not completely satisfied. Therefore, despite the high organic and industrial load of the considered plant and the need to find an alternative system for chlorine, as chlorine disinfection has been banned in the Veneto region since December 2012, ozone efficiency is not completely satisfactory and other systems such as peracetic or performic acids and UV systems must be considered. [ABSTRACT FROM AUTHOR]

Plastic containers in the range of 5-20 L are widely used - especially in rural African settings - to collect, transport and store water for domestic use, including drinking, bathing and hygiene. The pathogen content of the waters in these containers has not been adequately characterized as yet. This paper presents the primary findings of a synoptic survey of drinking water quality samples from these containers and involved collection of bacterial indicator and pathogenicity gene data. In total, 571 samples of a variety of waters were taken in rural communities in South Africa and the Escherichia coli numbers measured. Of the E. coli positive samples, 46% (n = 148) were screened for the presence of E. coli pathogen gene markers. Though synoptic, the survey provided many insights into the issues that drove the study. Container use markedly degraded water quality as judged by indicator counts, even where improved water supply services were in place. Household container use also appeared to promote regrowth or contamination of containers with pathogenic E. coli strains. Polymerase chain reaction (PCR) analysis also showed that the diversity of potential pathogenic E. coli carrying virulence genes was great. All seven genes screened for (Ial, Stx1, Stx2, EaeA, Eagg, ST, LT) were found in the waters, alone or as mixtures (number of different combinations = 31) including those characteristic of the more dangerous invasive and haemorrhagic E. coli strains. Given the central role of containers in the management of water supply to rural communities, it is clear the microbiology of these waters requires much further characterization. [ABSTRACT FROM AUTHOR]

A quantitative microbial risk assessment model for estimating infection risks arising from consuming crops eaten raw that have been irrigated with effluents from stabilization ponds was constructed. A log-normal probability distribution function was fitted to a large database from a comprehensive monitoring of an experimental pond system to account for variability in Escherichia coli concentration in irrigation water. Crop contamination levels were estimated using predictive models derived from field experiments involving the irrigation of several crops with different effluent qualities. Data on daily intake of salad crops were obtained from a national survey in Brazil. Ten thousand-trial Monte Carlo simulations were used to estimate human health risks associated with the use of wastewater for irrigating low- and high-growing crops. The use of effluents containing 103104 E. coli per 100 ml resulted in median rotavirus infection risk of approximately 10-3 and 10-4 pppy when irrigating, respectively, low- and high-growing crops; the corresponding 95th percentile risk estimates were around 10-2 in both scenarios. Sensitivity analyses revealed that variations in effluent quality, in the assumed ratios of pathogens to E. coli, and in the reduction of pathogens between harvest and consumption had great impact upon risk estimates. [ABSTRACT FROM AUTHOR]

In this study, the microbial characteristics of rainwater in two tanks with different surface-to-volume ratios were investigated and compared to determine how the internal design features of storage tanks affect water quality. The particle and nutrient parameters of the rainwater, including turbidity, suspended solids, total organic carbon, and total phosphate, were lower in Tank 2, which had a surface-to-volume ratio 7.5 times greater than that of Tank 1. In addition, although the rainwater was collected from the same catchment area, the water in Tank 1 had greater numbers of bacteria, and the bacterial communities in the water differed between the two storage tanks. It appears that the differences in the inside surface structures of the rainwater tanks affected the microbial ecosystems. Increasing the surface-to-volume ratio in rainwater tanks may affect rainwater quality, because this extends the area for biofilm development. Further study of the role of biofilm in rainwater tank is required precisely, and its function needs to be considered in the design and management of rainwater tanks. [ABSTRACT FROM AUTHOR]

In this study, we investigated the phylogenetic distribution of the bacteria present in an operating rainwater tank by denaturing gradient gel electrophoresis (DGGE), and compared the bacterial composition in rainwater and biofilm from the inlet and outlet of the tank. Seventeen species were identified, the DGGE profiles of which showed a clear difference between the planktonic bacterial community and the community in the biofilm. Most of the bacteria were closely related to fresh water, soil, and biofilm bacteria found in natural environments. The high proportion of Proteobacteria indicates the generally clean oligotrophic nature of the tank water. Biofilm formation is an advantage for bacteria that exist in oligotrophic environments. The groups identified in the biofilm, such as Sphingomonas, Bacillus, and Sphingophyxis, have been demonstrated to degrade certain contaminants and to act as bio-control agents. Thus, biofilm formation in rainwater tanks not only represents a survival strategy for bacteria, but also serves as a natural filter by removing contaminants and bacteria from rainwater. [ABSTRACT FROM AUTHOR]

Cladophora in the Great Lakes grows rapidly during the warm summer months, detaches, and becomes free-floating mats as a result of environmental conditions, eventually becoming stranded on recreational beaches. Cladophora provides protection and nutrients, which allow enteric bacteria such as Escherichia coli, enterococci, Shigella, Campylobacter, and Salmonella to persist and potentially regrow in the presence of the algae. As a result of wind and wave action, these microorganisms can detach and be released to surrounding waters and can influence water quality. Enteric bacterial pathogens have been detected in Cladophora mats; E. coli and enterococci may populate to become part of the naturalized microbiota in Cladophora; the high densities of these bacteria may affect water quality, resulting in unnecessary beach closures. The continued use of traditional fecal indicators at beaches with Cladophora presence is inadequate at accurately predicting the presence of fecal contamination. This paper offers a substantial review of available literature to improve the knowledge of Cladophora impacts on water quality, recreational water monitoring, fecal indicator bacteria and microorganisms, and public health and policy. [ABSTRACT FROM AUTHOR]

This work aims to describe the effect of the feeding regime of anaerobic activity tests on the limit viscosity (μlim) evolution of the granules. Batch experiments were performed with 3 different sources of substrate: acetate, peptone, and glucose. Despite, the substrate origin was shown to affect the μlim evolution of granules, no clear relationship was found between the μlim evolution, type of substrate and other granule physico-chemical characteristics (i.e. pH; % of Volatile Suspended Solid; concentration of exopolymeric substances, divalent cations, P and S). The origin of granules and the substrate feeding regime modify the surface shape of the granules and may change granule-granule interactions under a shear stress, thus affecting the evolution of the μlim value during long term reactor operation. [ABSTRACT FROM AUTHOR]

Vast volumes of groundwater are drained by urban sewer systems. This unwanted flow component intrudes into sewer systems through leaky joints or connected house drains. However, unlike urban storm drainage, it has a high seasonal variation corresponding to groundwater storage and long slow recessions similar to baseflow in rivers also fed by shallow groundwater exfiltrating into the surface waters. By applying the nonlinear reservoir algorithm as used for baseflow separation from total flow in a river, groundwater flow is separated from daily measured influents to treatment plants in Lower Saxony and Baden-Württemberg, Germany and in the Terkos Lake watershed near Istanbul, Turkey. While waste water flows vary only moderately within a year, separated intruded groundwater flows show recessions and seasonal variations correlated to baseflow in neighbouring rivers. It is possible to conclude that recession characteristics of treatment plant influents allow quantification and prediction of groundwater intrusion into sewer systems. [ABSTRACT FROM AUTHOR]

The present study was conducted to evaluate the specific acetate uptake rates of microorganisms with and without polyhydroxyalkanoates (PHA) accumulation. Activated sludge was aerobically incubated with 75mgCL-1 radiolabeled or non-labeled acetate, and acetate consumption and PHA accumulation were monitored. Microorganisms were quantified as follows: all microbial cells by DAPI staining, whole acetate utilizing organisms by microautoradiography, and PHA-accumulating organisms by staining with Nile blue A. The abundance of acetate-utilizing organisms without PHA accumulation was also calculated from the outcomes. The estimate of acetate utilized by PHAAOs included both the acetate converted to PHA and that used to supply reducing power and ATP. Acetate utilized by PHAAOs and non-PHAAOs were divided by their respective abundances to obtain their respective specific acetate uptake rates: PHAAOs ranged between 5.3 and 8.0 × 10-10 mgCcell-1 h-1, and non-PHAAOs ranged between 2.8 and 4.2 × 10-10mgCcell -1 h-1. [ABSTRACT FROM AUTHOR]

This work analyzes the kinetic modelling of the photocatalytic inactivation of E. coli in water using different types of kinetic models; from an empirical equation to an intrinsic kinetic model including explicit radiation absorption effects. Simple empirical equations lead to lower fitting errors, but require a total of 12 parameters to reproduce the results of four inactivation curves when the catalyst concentration was increased. Moreover, these parameters have no physical meaning and cannot be extrapolated to different experimental conditions. The use of a pseudomechanistic model based on a simplified reaction mechanism reduces the number of required kinetic parameters to 6, being the kinetic constant the only parameter that depends on the catalyst concentration. Finally, a simple modification of a kinetic model based on the intrinsic mechanism of photocatalytic reactions including explicit radiation absorption effects achieved the fitting of all the experiments with only three parameters. The main advantage of this approach is that the kinetic parameters estimated for the model become independent of the irradiation form, as well as the reactor size and its geometrical configuration, providing the necessary information for scaling-up and design of commercial-scale photoreactors for water disinfection. [ABSTRACT FROM AUTHOR]

In this study ten laboratories in Greece compared the performance of reference method TTC Tergitol 7 Agar (with the additional test of b-glucuronidase production) with five alternative methods, to detect E. coli in water, in line with European Water Directive recommendations. The samples were prepared by spiking drinking water with sewage effluent following a standard protocol. Chlorinated and non-chlorinated samples were used. The statistical analysis was based on the mean relative difference of confirmed counts and was performed in line with ISO 17994. The results showed that in total, three of the alternative methods (Chromocult Coliform agar, Membrane Lauryl Sulfate agar and Trypton Bilex-glucuronidase medium) were not different from TTC Tergitol 7 agar (TTC Tergitol 7 agar vs Chromocult Coliform agar, 294 samples, mean RD% 5.55; vs MLSA, 302 samples, mean RD% 1; vs TBX, 297 samples, mean RD% 22.78). The other two alternative methods (Membrane Faecal coliform medium and Colilert 18/ Quantitray) gave significantly higher counts than TTC Tergitol 7 agar (TTC Tergitol 7 agar vs MFc, 303 samples, mean RD% 8.81; vs Colilert-18/Quantitray, 76 samples, mean RD% 18.91). In other words, the alternative methods generated performance that was as reliable as, or even better than, the reference method. This study will help laboratories in Greece overcome culture and counting problems deriving from the EU reference method for E. coli counts in water samples. [ABSTRACT FROM AUTHOR]

We describe a novel assay for simple, rapid and high-sensitive detection of Cryptosporidium oocysts in water samples using a reverse transcription-loop-mediated isothermal amplification (RT-LAMP). The assay is based on the detection of 18S rRNA specific for Cryptosporidium oocysts. The detection limit of the developed RT-LAMP assay was as low as 6 × 10-3 oocysts/test tube, which theoretically enables us to detect a Cryptosporidium oocyst and perform duplicated tests even if water samples contain only one oocyst. The developed RT-LAMP assay could more sensitively detect Cryptosporidium oocysts in real water samples than the conventional assay based on microscopic observation. [ABSTRACT FROM AUTHOR]

Inhibition factors of urea hydrolysis caused by fecal contamination as source of urease were investigated. The urea hydrolysis was described by initial ammonification rate (IAR). Three factors for the inhibition (pH, free ammonia nitrogen (FAN) and salinity) were investigated in this study. It was found that the optimum pH value for the urea hydrolysis was obtained at pH 7 (30°C). Similar results were obtained from pH 5 to pH 8 whereas pH 9 provided a little amount of negative effect on the hydrolysis. Significant effect of the FAN as inhibition factor on the urea hydrolysis was obtained in the urea solution: the hydrolysis was observed within 120 mg-N/l of the FAN level in artificial urea solution with fecal contamination. However in storage process of real urine the urea hydrolysis was observed until the FAN level increased up to 2,000 mg-N/l. Salinity obviously provided negative effect on the urea hydrolysis in stored urine with fecal contamination at 30°C. It was assumed that high concentration of the NaCl (150 g/l) was required to achieve 50% reduction of the IAR. [ABSTRACT FROM AUTHOR]

Methylene blue (MB) has been shown to photoinduce the direct inactivation of Gram-positive bacteria Staphylococcus aureus (S. aureus) in water. We have investigated the mechanism of S. aureus photoinactivation conducting firstly sodium azide (reactive ion N3- 2), as a good physical singlet oxygen quencher, then the amino acids tryptophan (Trp), as a non-specific singlet oxygen quencher and the mannitol, as an hydroxyl free radical scavenger. Inactivation of MB photosensitization is the antioxidants type dependent. When the bacteria was treated with MB (20μM) under light during 10 min of exposure, it was found that survival fraction had decreased dramatically to about 31.27 ± 5.39%. The presence of sodium azide and Trp failed to shown any protection from the MB photodynamic activity. In the presence of mannitol, S. aureus could be protected, reaching a protection level of about 27%. It is possible that the photodynamic activity of MB occurred in part, via a Type I mechanism in which zOH was produced. The interactions between MB and S. aureus were studied spectrophotometrically. This demonstrated that a metachromatic reaction took place between MB and S. aureus bacteria. Furthermore, S. aureus bacteria induced additional dimerization of MB. [ABSTRACT FROM AUTHOR]

Polymerase chain reaction (PCR) provides a reliable detection of pathogenic bacteria in water samples. However, this method can be adversely influenced by the purity of the DNA template. This is a particularly important obstacle when the bacterial DNA is directly extracted from water samples. In this study we compared the suitability of 8 different methods for isolation of bacterial DNA from pure cultures and 10 different methods for isolation of DNA from water samples. The quality of extracted DNA was assessed by PCR amplification of target sequences derived from uid (E. coli and Shigella sp.), tuf (Enterococcus sp.) and hns (Salmonella sp.). Results indicated that there are differences among the methods tested and only a few of them gave satisfactory results. The method based on alkaline lysis of bacterial suspension, which was developed in our laboratory, seemed to be efficient enough for the detection of bacteria from pure cultures. Detection of bacteria directly from water samples was more difficult. The modified method developed by Slusarenko was found as the best of the tested methods. [ABSTRACT FROM AUTHOR]

Toilet wastewater is treated and reused on site at Europe's highest membrane bioreactor (MBR), located in a cable car mountain station in the ski resort of Zermatt. Negative impacts on the sensitive mountain environment are minimised by reusing close to 100% of the treated wastewater for toilet flushing. Besides 100% nitrogen removal, 80% of phosphorus was also eliminated. This paper presents operational results, optimisations of sludge management, decoloration and long-term maintenance of biomass in the very low-loaded summer season. From a global view the experiences and results of the project are of great importance, proposing a solution to a problem existing 100-fold in the Alps as well as in arid regions all over the world: reducing water consumption for sanitation by reuse. [ABSTRACT FROM AUTHOR]

This article presents a reliability analysis of 116 full-scale pond systems in Brazil, comprising 73 primary facultative ponds and 43 anaerobic--facultative pond systems. A methodology developed by Niku et al. (1979) is used for the determination of the coefficients of reliability, in terms of the compliance of effluent BOD, COD, TSS and FC to discharge standards or effluent quality targets. The design concentrations necessary to meet the prevailing discharge standards and the expected compliance percentages have been calculated from the coefficients of reliability obtained. The results showed that few units, under the observed operating conditions, would be able to present reliable performances in terms of compliance with the analyzed standards. For the four constituents (BOD, COD, TSS and FC) and both systems (facultative ponds and anaerobic-facultative systems), the variability of the effluent quality was very large, leading to a high variability of the coefficient of variation (CV) and the coefficient of reliability (COR). The effluent quality from the facultative ponds showed a larger distance to both the desired values and the discharge standard values, compared with the anaerobic--facultative systems. [ABSTRACT FROM AUTHOR]

Increasing concern about bathing water quality in Scotland has led to renewed interest in diffuse sources, as well as the already closely monitored municipal sewage effluents and combined sewer overflows (CSOs) that have been the subject of multi-million pound capital expenditure schemes for several years. Early investigations of diffuse sources focused on rural land uses. This paper is an initial effort to consider the possible significance of urban diffuse sources. A review of the potential for diffuse urban sources includes consideration of sewage pollution in surface water sewers, as well as non-human sources such as pigeon and other bird roosts, and faecal material from pets such as dogs and cats. Portobello beach in Edinburgh is the case study selected, because of earlier work done by Scottish Water and SEPA. The Figgate Burn crosses Edinburgh to discharge onto the beach at Portabello, and pollution sources in its catchment are described. Additional information is reported from Dunfermline, where the sewer network has provided examples of three ways in which sewage pollution can occur in urban streams, and also Scottish examples of measures to control some non-human sources (e.g. SUDS). [ABSTRACT FROM AUTHOR]

An assessment of the impact of the new microbial water quality standards of the proposed EU Bathing Water Directive on the classification of designated Irish coastal bathing areas is presented. The new standards are applied retrospectively to the microbial water quality results for the bathing seasons of 1999, 2000 and 2001, and the outcome is compared with that recorded under the present Bathing Water Directive. A Microsoft EXCEL application was developed to generate the retrospective bathing area classifications according to the proposed Directive (Excellent, Good, Poor). It was found that the number of Irish coastal bathing areas not attaining 'Excellent' classification (as would be required at present for the Blue Flag award) was trebled; the number attaining 'Good' classification was increased by about 50%, and the number attracting 'Poor' classification (equivalent to 'Fail' under the present Directive) was increased nine-fold. Some of the shortcomings of the proposed Directive and suggestions for its revision are discussed. [ABSTRACT FROM AUTHOR]

To ensure optimum quality at Bathing Waters, the control of diffuse sources of bacterial contamination is receiving increasing attention. As part of an initiative to improve the quality of the EU designated bathing waters on the Fylde Coast (North West England), a project was undertaken to quantify the faecal indicator load from birds and assess the significance on water quality. High bird counts are encountered on the Fylde Coast with gulls, feral pigeons and starlings being prominent. The piers at Blackpool make an attractive roost for starlings with numbers peaking at over 30,000 in late summer. Systematic recording of bird numbers and locations was undertaken during 2001/2. Estimates were also made of the daily faecal organism production by the different species. The spatial distribution of faecal organisms from the bird population was statistically linked to synoptic water quality data. This allowed estimates to be made of the contribution from birds to the faecal pollution load at the bathing waters. The work confirmed a statistically significant link between bird populations and water quality with a marked seasonal bias. [ABSTRACT FROM AUTHOR]

Achieving compliance with the mandatory standards of the 1976 Bathing Water Directive (76/160/EEC) is required at all UK identified bathing waters. In recent years, the Fylde coast has been an area of significant investments in 'point source' control, which have not proven, in isolation, to satisfactorily achieve compliance with the mandatory, let alone the guide, levels of water quality in the Directive. The potential impact of riverine sources of pollution was first confirmed after a study in 1997. The completion of sewerage system enhancements offered the potential for the study of faecal indicator delivery from upstream sources comprising both point sources and diffuse agricultural sources. A research project to define these elements commenced in 2001. Initially, a desk study reported here, estimated the principal infrastructure contributions within the Ribble catchment. A second phase of this investigation has involved acquisition of empirical water quality and hydrological data from the catchment during the 2002 bathing season. These data have been used further to calibrate the 'budgets' and 'delivery' modelling and these data are still being analysed. This paper reports the initial desk study approach to faecal indicator budget estimation using available data from the sewerage infrastructure and catchment sources of faecal indicators. [ABSTRACT FROM AUTHOR]

New and improved methods have been developed to detect somatic and male-specific coliphages in large volumes of water by single agar layer (SAL), enrichment and membrane filter methods. Somatic coliphages were detected efficiently on E. coli hosts C and CN13, male-specific coliphages were detected more efficiently on E. coli Famp than on Salmonella typhimurium WG49 and both types of coliphages were detected simultaneously on E. coli C3000. For water volumes of up to 100 ml, the SAL method was efficient and reliable. For water volumes of <1 L and as many as 10 multiple 1 L volumes, the enrichment method was efficient in detecting very low numbers of coliphages. Membrane filter methods, in which coliphages were adsorbed to and eluted from filters, also were relatively efficient, but they were less efficient than SAL and enrichment methods and were considered to be more cumbersome. For filter adsorption-elution methods, coliphage recoveries were most efficient for cellulose ester filters, less efficient for electropositive 1MDS filters and least efficient for a direct membrane filter method. Overall, the enrichment method was preferred because of its ability to easily and rapidly detect low levels of coliphages in large sample volumes by either presence--absence or most probable number quantification. [ABSTRACT FROM AUTHOR]

A human-impacted watershed was monitored during the dry summer seasons in 2002 and 2003 to investigate the impact of providing access to sewer mains to local village residences. Faecal coliform concentrations were monitored at select sites along the 30-mile stretch of creek, together with faecal streptococci, enterococci and total coliforms. Analysis of the results found that levels of faecal coliforms were inadequate at identifying significant known influxes of human and animal sewage established by sanitary survey. However, the bacterial ratio of atypical colonies to total coliform colonies (AC/TC), obtained from the total coliform membrane filter assay on m-Endo media, correctly indexed human faecal impact of inadequately sewered villages located along the creek. In addition, the AC/TC ratio correctly classified the predominant source of faecal runoff in the creek headwaters as agricultural, and indicated when aged agricultural faecal material was introduced by tributaries. An approach for watershed management that uses the AC/TC ratio in addition to levels of bacteria is proposed. [ABSTRACT FROM AUTHOR]

In this study the assessment of randomly amplified polymorphic DNA (RAPD) analysis was established as a molecular epidemiological tool. RAPD analysis was performed to differentiate faecal Escherichia coli isolates from human and animal sources. E. coli strains (128) were isolated from human and animal faeces (from cattle and sheep). Genomic DNA was extracted and randomly amplified polymorphic DNA-PCR (RAPD-PCR) fingerprinting was performed. Seven arbitrary primers were tested with a view to discriminating between E. coli isolates from humans and E. coli isolates from animals. RAPD profiles were analysed with hierarchical cluster analysis using an unweighted pair group method. RAPD profiles obtained with three of the tested primers (1247, 1290 and 1254) established a distinct differentiation between E. coli isolates from humans and E. coli from animals. Low levels of misclassification and high levels of specificity make RAPD a sensitive, efficient and reliable means of distinguishing closely related strains. [ABSTRACT FROM AUTHOR]

Antibiotic resistance profiling (ARP) is a potentially useful method for distinguishing faecal bacteria according to host source. This phenotypic approach has cost benefits over genotypic methods, but existing protocols are time-consuming and manual data handling is open to human error. A simplified, low-cost approach to the ARP technique was developed that used automated data recording techniques combined with simple statistical analyses to compare isolates of the genus Enterococcus from various faecal sources. An initial battery of 21 antibiotics (at up to four concentrations) was chosen for source discrimination. Images of growth or non-growth in microplate wells were stored as bitmaps and converted to binary data to form a database of known antibiotic resistance profiles. Discriminant function analysis (DFA) showed that the average rate of isolates correctly classified by the database (wastewater vs non-wastewater) was 86%. Once the more discriminating antibiotics and their concentrations had been identified, it was possible to reduce the number of tests from 80 to 18 whilst increasing the number of correctly classified human isolates. ARP could offer a low-cost and rapid means of identifying sources of faecal pollution. As such, the technique may be of particular benefit to developing countries, where water quality may have a significant impact on health and where cost is a major factor when choosing environmental management technology. [ABSTRACT FROM AUTHOR]

The supply of unfiltered disinfected drinking water from Melbourne's fully protected catchments means that the water-quality managers must ensure that the source water poses no public health risk. High turbidity is currently used as a surrogate of pathogens, and harvesting of water is based on its measurement. The work presented here summarises suspended particle and associated pathogen, microbial indicator and faecal biomarker concentrations collected to (a) quantify turbidity in an Australian water supply system and (b) assess the possibility of increasing water harvesting from selected tributaries. Pathogens and microbial indicators were present in low numbers in these source waters; increased turbidity during storm events was not associated with an increase in pathogen concentration. The results confirmed that protected catchments, along with good management, were effective barriers to pathogen contamination. Aesthetic issues still need to be addressed, but no measurable increase in microbiological risk was associated with storm-generated particles. [ABSTRACT FROM AUTHOR]

A database was examined using artificial neural network (ANN) models to investigate the efficacy of predicting PCR-identified Norwalk-like virus presence and absence in shellfish. The relative importance of variables in the model and the predictive power obtained by application of ANN modelling methods were compared with previously developed logistic regression models. In addition, two country-specific datasets were analysed separately with ANN models to determine if the relative importance of the input variables was similar for geographically diverse regions. The results of this analysis found that ANN models predicted Norwalk-like virus presence and absence in shellfish with equivalent, and better, precision than logistic regression models. For overall classification performance, ANN modelling had a rate of 93%, vs 75% for the logistic regression. ANN models were able to illuminate the site-specific relationships between indicators and pathogens. [ABSTRACT FROM AUTHOR]

A project was designed by Umgeni Water (funded by the Water Research Commission of South Africa) to monitor the implementation of water reticulation in Vulindlela and evaluate the Water Supply Scheme from a community and environmental health perspective. The findings would hopefully contribute toward the development of criteria for Health Impact Assessment on Water Reticulation Projects. One objective of this study was to evaluate the usefulness of diarrhoeal disease as opposed to other health indicators for water-associated diseases. The innovative methodology followed in the study, a "stepped wedge design", compared four discrete areas of water reticulation implementation in Vulindlela over a 15- month period. Five surveys, including a baseline and four follow-ups at each household, were carried out. Analysis (microbiological, chemical) was carried out of samples from the household drinking water and from the source of the water. Each survey included health questionnaires, the respondent being the head of the household in each case. Overall, there was no direct correlation proved between water quality and diarrhoea per se. However, there was a marked decrease in diarrhoea with the introduction of the new water supply. There was definite correlation between hygiene behaviours and diarrhoea. Diarrhoea would seem to be the health impact associated with water, of choice. [ABSTRACT FROM AUTHOR]

A population sample from a community in a developing urban area (Botshabelo), which obtains its treated water supply from a communal standpipe system, was subjected to a short Health and Hygiene Awareness and Education (HHA&E) programme to improve its practices on storing water in, and handling water from, storage containers at home. The problem was that the community's practices lead to the deterioration of the microbiological quality of the water in domestic storage containers. Measuring changes in the practices, as well as the microbiological quality of water in the containers, were the instruments used to determine whether the programme had a positive educational effect. This paper reports on selected elements of the practices measurement. Structured interviews, observations and statistical analyses assessed three variables -- container hygiene, container storage and hand hygiene. Results indicated insignificant improvements in practices. This was supported by insignificant improvements in the microbiological water quality, that was still above health-safety limits. This implied that short-term "quick fix" HHA&E programmes would tend to be ineffective. Results also suggested that some negative water-hygiene habits may readily change (container hygiene and storage), while behaviour of a more personal nature, such as hand-washing, was not easily changed. [ABSTRACT FROM AUTHOR]

AQUASIM is a computer program for the identification and simulation of aquatic systems. The program includes a one-dimensional multisubstrate and multispecies biofilm model and represents a suitable tool for biofilm simulation. The program can be used to calculate substrate removal in biofilm reactors for any user specified microbial system. One-dimensional spatial profiles of substrates and microbial species in the biofilm can be predicted. The program also calculates the development of the biofilm thickness and of the substrates and microbial species in the biofilm and in the bulk fluid over time. Detachment and attachment of microbial cells at the biofilm surface and in the biofilm interior can be considered, and simulations of sloughing events can be performed. Furthermore, AQUASIM allows pseudo two-dimensional modeling of plug flow biofilm reactors by a series of biofilm reactor compartments. The most significant limitation of the model is that it only considers spatial gradients of substrates and microbial species in the biofilm in the direction perpendicular to the substratum. [ABSTRACT FROM AUTHOR]

The paper uses the technique of Monte Carlo simulation in order to investigate the sensitivity to the Dispersion Number (d) of the effluent coliform concentration from facultative and maturation ponds. The Dispersion Number is one of the coefficients used in the dispersed-flow model for ponds. Initially, four empirical equations available in the literature for the estimation of d were compared, using the results from 1,000 runs of the Monte Carlo simulation. A second different set of Monte Carlo simulations (1,000 runs) was undertaken, allowing a sensitivity analysis of d, in conjunction with other coefficients and input data used in the design of facultative and maturation ponds (e.g., population, wastewater flow, coliform removal coefficient and others). The results of the simulations suggest that, when considering the high level of uncertainty in all input variables used in the design of the ponds for coliform removal, the Dispersion Number d does not present a greater influence in the model prediction, compared with the other input variables. Based on these considerations, it is likely that, for design purposes, simple models for the prediction of d can be used, without significantly affecting the estimation of the effluent coliform concentration, considering the existing uncertainty in all other input variables. [ABSTRACT FROM AUTHOR]

A pond system consisting of two lines each of an anaerobic followed by facultative and maturation ponds is used to treat site sewage from oil and gas production operations in an arid coastal environment. The performance of the pond system was evaluated together with the suitability of treated effluent for reuse in local irrigation. Effluent from the pond system by-and-large satisfies criteria for irrigation of non-food crop plants with respect to chemical parameters. The primary problem is coliform bacteria levels which are an order of magnitude higher than preferred values. First-order decay rate constants for each pond were calculated from a mass balance model that assumes complete mixing and incorporates the considerable evaporation that occurs in this setting. While the anaerobic ponds of both lines exhibit suitable performance, rate calculations indicate that the facultative and maturation ponds of the East Line are performing better than the West. A tracer study of the facultative and maturation ponds indicates that some short-circuiting is occurring in the West Line. A field experiment of coliform transport in irrigated soil gives indications of shortand long-term risks associated with reuse of the effluent. [ABSTRACT FROM AUTHOR]

Focuses on the electrochemical monitoring probe (BIOX) recently developed to improve the antifouling treatments of cooling systems in industrial plants. Results from applications on marine sites suggesting some validation of this technique in biofilm growth and prevention of microbial corrosion in fresh and drinking waters.

Analyzes the inactivation of Cryptosporidium parvum oocysts and other microbes in water and wastewater by electrochemically generated mixed oxidants. Oocyst viability in wastewater experiments; Doses of the mixed oxidants for inactivation of oocysts; Extent and rate of inactivation.

Presents an optimized and standardized test to determine the presence of the protozoa Cryptosporidium and Giardia in water. Concentration of oocysts and cysts; Recovery of oocysts and cysts from treated water by membrane filters; Recovery of cysts and oocysts from water concentrates using immuno-magnetic systems.

Focuses on the survival and transfer of fecal indicator organisms of wastewater effluents in receiving lake waters. Determination of indicators such as fecal coliforms, enterococci, sulphite-reducing clostridia and coliphages; Abundance of coliphages or enterococci at distant sample sites; Data suggesting that the direct use of lake water could be considered a health risk.

Details a method for the prioritization of areas experiencing microbial pollution of surface water. Measurement values for intensive farming enterprises; Objective selection of areas of incorporation in the microbial monitoring program; Adaptability of the method for use under other circumstances once the land and water uses and their impacts have been identified.

This study was initiated by the AFNOR water microbiology working group to evaluate the performance of the glass wool method for virus recovery. Its reliability was tested with drinking and sea water by respectively nine and thirteen laboratories. In both trials, six were actively involved in water virology research, one was designated as a central laboratory, the others had no experience in virological practices. Analysis of reproducibility and repeatability according to NF-ISO 5725-2 were realized. For drinking waters (24 assays), the average recovery efficiency was 72%, mean standard deviations: repeatability 12.4%; reproducibility 33.6%; inter-laboratories 21%. For sea waters (39 assays), the average recovery efficiency was 75% and the mean standard deviations 6.9%, 17.9% and 11% respectively. [ABSTRACT FROM AUTHOR]

Enzymatic hydrolysis of fluorogenic substrates (4-methylumbelliferyl-β-D-galactoside, 4-methylumbelliferyl-β-D-glucuronide) has been used for rapid (25min) detection of indicators of faecal water pollution, i.e. coliform and tbermotolerant coliform bacteria. In the present work, enzymatic activities and different groups of bacteria (i.e. thermotolerant coliforms, coliforms, β-galactosidase positive and β-glucuronidase positive bacteria) from sewage effluent and polluted river water have been investigated. Ratios of the order of 1:10 between coliforms and β-galactosidase positive bacteria were demonstrated. The contribution from β-galactosidase positive non-coliform bacteria to the measured enzyme activity should not, therefore, be neglected. Numbers of β-glucuronidase positive non-coliforms indicate interference of this group in the rapid assay. [ABSTRACT FROM AUTHOR]

This study compared a chromogenic and fluorogenic substrate based medium, Colisure, with the conventional fermentation based medium, lauryl tryptose broth (LTB), for the recovery of chlorine-injured and non-injured cotiforms and E. coli. Mixed natural populations of coliforms from sewage, with and without chlorine exposure, and untreated surface water samples were examined following a USEPA established procedure. Colisure and LTB were examined after 20, 24, 28 and 48h incubation and reactions verified. There were slight increases in positive reactions over time with unchlorinated samples, for which the two media gave similar kinetic patterns. The increases over time with chlorinated samples were much greater than with unchlorinated samples. LTB gave significantly lower total positive responses and had a more pronounced lag period than did Colisure. Total coliform bacteria from surface water samples gave somewhat different reactions with more of an increase with time. Colisure recovered comparable or higher numbers of total coliforms and E. coil in 20-28h than LTB after 48h. These results confirm that Colisure gives improved recovery of chlorine-injured total coliforms and E. coli under conditions simulating treated drinking and source water, resulting in a more realistic estimate of the actual population of indicator bacteria in public water supplies. [ABSTRACT FROM AUTHOR]

Two potable water quality monitoring tests, the H2S paper strip test and coliphage test, were evaluated on Chilean raw potable source waters and drinking waters that had received conventional treatment to render them safe for drinking. Based on 108 samples in this study, it was found that the H2S paper strip provided consumers with equivalent to, or greater protection than, the total coliform MPN test. In treated water, a highly significant relationship (P = <0.0001) between total coliforms and H2S paper strip tests was observed. Significant relationships were also observed between total coliforms/coliphage and residual chlorine/H2S paper strip test. These studies provide evidence that the H2S paper strip test and the coliphage test are viable indicators of potable water quality and water treatment in two medium-sized cities in Chile. [ABSTRACT FROM AUTHOR]

Cryptosporidium parvum is an infectious enteric protozoan parasite that causes waterborne disease, severe gastroenteritis and is associated with high mortality in immunocompromised individuals. Detection of oocysts in water is very difficult and current methodologies do not determine viability. This project has focused on low level detection of Cryptosporidium parvura in environmental samples using a unique cultural method. Previously, cell culture methods have been used to assess the developmental stages of Cryptosporidium; however, no cultural methods have been employed with environmental samples. The percentage of viable oocysts can be estimated by detecting intracellular developmental stages of the parasite using fluorescently labelled antibodies. Other methods are not capable of low level detection or high sensitivity. We are evaluating detection of single foci of infection, indicating that one of the four sporozoites released from the viable oocyst has infected a single cell. [ABSTRACT FROM AUTHOR]