bluuebunny/crossref_metadata_2025 huggingface dataset:
Monitoring strategy for lead in drinking water at consumer's tap: field experiments in France
Authors: Baron J.
Published: May 2018

Following the outcome of a European project for developing a new protocol for the monitoring of lead in drinking water, field experiments have been carried out in five supply zones in France in order to test and develop practical tools for assessing compliance/non-compliance for lead. A number of properties in each zone were randomly selected and random daytime (RDT), 30 minutes stagnation (30MS) and fully flushed (FF) samples taken. The results confirm that, at zone level, RDT or 30MS samples taken in a sufficient number of properties give almost identical results. RDT is more practical and acceptable to the consumer whereas 30MS is more reproducible and should be preferred for assessment at an individual consumer's tap. Random selection of properties appears to be a good solution for assessing the actual situation in a zone and help in the definition of priorities and type of actions to implement. Copper and nickel have also been controlled in three zones and the monitoring strategy for lead could also be used for these parameters.
The effect of distribution system bacterial biofilms on copper concentrations in drinking water
Authors: Critchley M.M. , Fallowfield H.J.
Published: May 2018

This study investigated the potential for distribution system biofilm bacteria to elevate copper concentrations in drinking water. Biofilms were sampled from household copper reticulation pipes and grown on R2A agar. Laboratory coupon experiments were used to determine the effect of single isolate biofilms on aqueous copper concentrations. The majority of biofilm bacteria did not affect copper concentrations in comparison to sterile controls. However, several bacteria including Acidovorax delafieldii, Cytophaga johnsonae and Micrococcus kristinae were shown to significantly elevate copper concentrations in drinking water. In contrast, the bacteria Rhodococcus sp. and Xanthomonas maltophilia were shown to significantly decrease copper levels in comparison to controls. The significance of biofilm bacteria to increase copper concentrations in drinking water has implications for public health by increasing concentrations to levels toxic to humans.
Effect of operational modes on the removal of a synthetic organic chemical by powdered activated carbon during ultrafiltration
Authors: Matsui Y. , Yuasa A. , Colas F.
Published: May 2018

The effects of operational modes on the removal of a synthetic organic chemical (SOC) in natural water by powdered activated carbon (PAC) during ultrafiltration (UF) were studied, through model simulations and experiments. The removal percentage of the trace SOC was independent of its influent concentration for a given PAC dose. The minimum PAC dosage required to achieve a desired effluent concentration could quickly be optimized from the C/C0 plot as a function of the PAC dosage. The cross-flow operation was not advantageous over the dead-end regarding the SOC removal. Added PAC was re-circulated as a suspension in the UF loop for only a short time even under the cross-flow velocity of gt; 1.0 m/s. The cross-flow condition did not contribute much to the suspending of PAC. The pulse PAC addition at the beginning of a filtration cycle resulted in somewhat better SOC removal than the continuous PAC addition. The increased NOM loading on PAC which was dosed in a pulse and stayed longer in the UF loop could possibly further decrease the adsorption rate.
Membrane vacuum stripping process for volatile organics removal from water using an asymmetric PVDF (polyvinylidene fluoride) hollow fiber membrane module
Authors: Wang D. , Li K. , Teo W.K.
Published: May 2018

The vacuum membrane stripping process (VMS) for removing a VOC (trichloroethylene) from water was studied in a polyvinylidene fluoride (PVDF) hollow fiber membrane module containing 187 fibers with a length of 0.59 m. The porous PVDF asymmetric hollow fiber used was prepared by the wet phase inversion technique. The feed solution containing trichloroethylene (TCE) was passed through the lumen of the PVDF hollow fiber. Vapors of TCE and water were transported through the pores of the membrane into the shell side maintained at a sub-atmospheric pressure, and condensed in cold traps. The effects of down-stream pressure, solution temperature, feed concentration, and feed flow rate on TCE removal, TCE permeation flux, water permeation flux and TCE concentration of the permeated solution, as well as the mass transfer coefficient were investigated. The down stream pressure and solution temperature were identified as the major factors to control VOC removal and TCE concentration in the permeate stream. A small amount of the permeated solution with higher TCE concentration was obtained at the temperature of 50°C and pressure of 80 mmHg when about 90% TCE was removed from the water.
Reuse of filter backwash water by implementing ultrafiltration technology
Authors: Brügger A. , Voßenkaul K. , Melin T. , Rautenbach R. , Golloing B. , Jacobs U. , Ohlenforst P.
Published: May 2018

Membrane filtration allows safe retention of microorganisms when treating filter backwash water from conventional drinking water filters. The permeate of the membrane plant can thus be reused to produce drinking water. The benefits are a higher yield of the drinking water treatment plant and a minimised wastewater production. This paper discusses the results of a pilot study, cost data and full-scale operation experiences concerning the application of ultrafiltration to treat filter backwash water. The effectiveness of ultrafiltration was assessed with regard to flux, cost and permeate quality.
Evaluation of nanofiltration for disinfection by-products control in drinking water treatment
Authors: Itoh M. , Kunikane S. , Magara Y.
Published: May 2018

DBP control by nanofiltration was studied. Nine DBPs including THMs were selected as target compounds. Reagent DBPs and DBPs formed as a result of chlorination of NOM contained in river water, were applied to nanofiltration to examine DBPs removal. Humic acid was used to investigate DBP precursor control. Nanofiltration was conducted for about one day for each experiment using two 2-inch membrane modules. NF showed high performance for DBP precursor removal but little effect on the removal of DBPs themselves, especially THMs. In the experiment of DBP precursors removal, rejections were 98 to 100 percent for most of the DBPFPs. For NOM in river water, rejections of THMFPs were 96 to 99 percent. This shows nanofiltration is effective even at low concentrations of NOM. Nanofiltration can remove almost all organic substances with the apparent molecular weight of greater than 2,000 daltons. Molecular weight distribution patterns of the permeate were different depending on NF. THMs showed decreasing rejection as filtration proceeded because of adsorption on the membrane surface. THM rejections at 24 hours after filtration started were about 10 and 30 percent in Module-A and B, respectively. Haloacetic acids showed relatively higher rejections. It is recommended, from the viewpoint of THM control, that NOM removal using NF is much preferable to the removals of THM, formed by chlorination, using NF.
Flux enhancement by glass balls inserted membrane module
Authors: Kim J.-P. , Kim J.-J. , Chun M.-S. , Min B.R. , Chung K.Y.
Published: May 2018

The glass ball inserted membrane module presented in this study is designed to enhance filtration in a flat sheet membrane. Three different modes of filtration experiments were conducted and compared to demonstrate flux enhancement due to the presence of glass balls: a normal dead-end filtration, a vortex flow filtration, and an enhanced vortex flow filtration using glass balls. In the case of enhanced vortex flow filtration the permeate flux was found to be three times as large as that of the dead-end filtration, and two times larger compared with the vortex flow filtration. In addition, the flux decline was observed to be relatively low. The effect of the amount of glass balls on the permeate flux was also investigated by changing the values of glass ball volume fraction from 0.059 to 0.356. It has been observed that the permeate flux shows a maximum value of the volume fraction of 0.119. For the glass ball inserted membrane module, the permeate flux tends to increase with the feed flow rate.
Impact of pretreatment on UF operation and removal of dissolved organics
Authors: Braghetta A. , Price M. , Hentz C. , Stevenson E. , Kolkhorst C.
Published: May 2018

Pilot testing of low-pressure membrane filtration (microfiltration and ultrafiltration) was performed on surface waters at two different pilot locations: the Alameda County Water District (ACWD) in Fremont, CA and the Medina River outside San Antonio, TX. Clarification pretreatment and adsorption pretreatment were evaluated at each site for impacts on operational membrane performance and on removal of dissolved organic compounds including total organic carbon (TOC), UV254, color and precursors to disinfection by-products. At the ACWD test site, studies were also conducted with spiking of taste and odor-causing compounds. In both pilot studies, clarification pretreatment was demonstrated to achieve some apparent improvement in operating efficiency. For example, an apparent increase in sustainable flux between 25% and 50% was demonstrated for clarified feedwater operation as compared to raw feedwater operation at the ACWD pilot site. Removal of dissolved organic compounds was achieved primarily through the pretreatment with clarification and/or addition of powdered activated carbon (PAC); however, some reduction of TOC and color was achieved via membrane filtration presumably due to removal of particulate/colloidal constituents.
The application of new technologies in the water treatment process of a modern waterworks
Authors: Hoyer O. , Clasen J.
Published: May 2018

The new plant for the treatment of water from the Wahnbach-reservoir went into operation at Siegburg, Germany in 2001. It will have a capacity of 3,600 to 4,800 m3/h and is intended for drinking water supply of the Bonn region. The relatively simple water treatment process achieves its high performance and safety from the sophisticated process layout and control developed from 40 years of research and experience at the Wahnbach Reservoir Association.

According to temporal needs permanganate and/or powdered activated carbon can be applied for pretreatment. Flocculation is either possible with Al3+- or Fe3+-salt solutions introduced by optimized flash-mixing and destabilization. Immediately afterwards at the inlet into the 12 aggregation and filtration trains it is possible to inactivate motile planktonic organisms by means of cavitation fields generated by ultrasound at 40 kHz. In the following aggregation step flocs are generated tailored to optimum retention in the double media filters which are regenerated via high speed build-up backwashing. Release of plankton and microorganisms accumulated in the filter bed by motile plankton is inhibited by the ultrasound treatment.

A continuously high filtrate quality is achieved by stacked filter-runs of the 12 filters adapted to the water quality with backwashes graded at equal time intervals after identical filter-run times, a filter to waste period after backwash first filtrate separation and permanent turbidity monitoring at the individual filtrate outlets.

Disinfection is achieved with 3 closed UV-systems equipped, performance tested and certified according to the DVGW technical standard W 294 and is followed by conventional. de-acidification with addition of lime water. The paper will describe and explain the process concept which has been worked out and validated by WTV within the framework of several research projects.
Advanced oxidation technologies for the degradation of pesticides in ground water and surface water
Authors: Ijpelaar G.F. , Groenendijk M. , Hopman R. , Kruithof Joop C.
Published: May 2018

An overview of the Advanced Oxidation Processes (AOP) studied for the degradation of pesticides combined with the formation of by-products is presented. It was found that the degree of conversion of pesticides is about the same with the Fenton process and UV/H2O2 within the margin of practical application, but slightly different with ozone/H2O2. Bentazone is readily degraded by the latter process, but more persistent during water treatment with the Fenton process and UV/H2O2, whilst atrazine is difficult to convert with all of these processes. Although bromate formation cannot be avoided completely with ozone/H2O2, it can be realized with the Fenton process and UV/H2O2. Upon degradation of pesticides with UV/H2O2 nitrite is produced, the amount depending on the water quality with respect to the nitrate concentration. Based on the a-selective nature of the hydroxyl radical AOC is formed out of DOC, which indicates that ozone/H2O2, the Fenton process as well as UV/H2O2 should be applicable for the development of biological GAC filtration.
Monitoring for Cryptosporidium risk: do particle counters help?
Authors: Morse A. , Wilson R. , Hull A. , Simms J.
Published: May 2018

Turbidity measurements are used extensively for monitoring water quality, and as a warning for process failure which may carry a risk of Cryptosporidium breakthrough. However, turbidity is most sensitive to particles in the submicrometre size range, whereas Cryptosporidium is 4-6 μm in diameter. The question therefore remains - do particle counters help in monitoring for the risk of Cryptosporidium breakthrough?

A full year study was undertaken at a direct river abstraction works. The project aimed to establish whether particle counts can be used to predict an increased risk of Cryptosporidium breakthrough. Although protozoan (oo)cysts were often present in low numbers in the raw water, none was detected in the final water. Particle counts and turbidity measurements were carried out on three RGFs and the raw and clarified water. Online Cryptosporidium and Giardia samples were also taken daily from the three RGFs being monitored for particles, and bacteriological analyses were carried out on the same sample points. Other plant parameters and environmental factors were also monitored.

Particle counts from RGFs varied significantly. The main factors influencing the filtered water particle count appeared to be raw water turbidity and algal counts, and the particulate loading rate to the filters.
Contamination potential of biofilms in water distribution systems
Authors: Flemming H.-C. , Percival S.L. , Walker J.T.
Published: May 2018

Biofilms are ubiquitous in drinking water systems, either in the form of thin and patchy colonies or as surface-covering multiple layers. In biofilters they are used for the elimination of biologically degradable substances. However, they occur in other sites, e.g., on the walls of containers and pipes, on sediment and on suspended particles. They can rise problems by contamination of the water phase by detaching biofilm organisms. Biofilms provide a possible habitat for hygienically relevant microbes in which they can persist and even multiply. Here they are protected against disinfectants, in particular if located in corrosion products, sediments or ingested by protozoa which feed on biofilm cells. Biofilms are related to the occurrence of “black water” and malodours. They are involved in the corrosion of metals, mineral materials and synthetic polymers. The limiting factor for biofilm growth is usually the availability of nutrients, mainly provided either by biodegradable substances leaching from materials or from by the water phase. The extent of biofilm growth and of the occurrence of hygienically relevant organisms is still unknown and to be investigated. However, latest research indicates that such organisms do not multiply in large numbers in drinking water biofilms; it is possible that drinking water biofilms can inhibit the propagation of invading pathogens.
A study on the removal of toxic metal-EDTA complex using solar light/TiO2 system
Authors: Cho I.-H. , Park T.-J. , Kim H.-Y. , Zoh K.-D. , Lee H.-K.
Published: May 2018

A circular reactor was placed outdoors to investigate the possibility of using natural sunlight in TiO2 photocatalysis system for the removal of toxic metals (Cd, Cr, Cu, Hg, Ni, Zn) and EDTA complex. The results show that the system containing both solar light and TiO2 more effectively removed metal-EDTA complex than either solar light or TiO2 system alone. The removal of each metal was more than 90% in the presence of TiO2/solar light, and EDTA (TOC basis) was reduced more than 80% in 120 min. Photocatalytic removal efficiency of heavy metal-EDTA increased with increasing TiO2 dosage. However, over 1.5g/L of TiO2 dosage, the efficiency reached a plateau.
Protection layers for the extension of slow sand filter running times in wastewater reuse
Authors: Mälzer H.-J. , Gimbel R.
Published: May 2018

The running time of slow sand filters in wastewater reuse is limited by the increase of pressure drop which is mainly caused by the surface filtration of suspended solids. Surface filtration mechanisms on the top of filter sand layer can be avoided e.g. by protection layers. Choosing suitable materials for protection layers a considerable extension of slow sand filter running times can be achieved.
A pilot plant study of polysilicato-iron coagulant
Authors: Wang J. , Deevanhxay P. , Hasegawa T. , Ehara Y. , Kurokawa M. , Hashimoto K. , Nishijima W. , Okada M.
Published: May 2018

A new inorganic polymer coagulant of polysilicato-iron (PSI) was evaluated as an alternative to aluminium coagulant. In this study, long-term performance of PSI on coagulation, sedimentation and filtration for phytoplankton, turbidity and DOC in raw water from a eutrophic reservoir were evaluated by a pilot plant in comparison with PAC. PSI was found to be more effective in the coagulation and removal in comparison with PAC. The flocs formed by PSI could be settled more quickly than those by PAC and, therefore, the size of sedimentation facilities can be reduced by the introduction of PSI. PSI was able to produce filtered water with low turbidity and colour. The number of phytoplankton cells in the filtered water of PSI was smaller than that of PAC. Most of the residual flocs in the settled water were trapped in the coarse layer of anthracite, and this result suggested that a higher rate of filtration can be achieved with PSI by increasing particle size of the filter media.
Using percentile analysis for determination of alarm values
Authors: Lake R.C. , Agutter P.A. , Burke T.
Published: May 2018

The use of statistically derived alarm values for the minimisation of the risk of Cryptosporidium entering the water supply has been recommended in the report of the Bouchier expert group. Values derived using the mean plus standard deviations can be skewed by spikes, including those caused by filter washes. Indeed, theoretically, the use of standard deviations should only be used with normally distributed data. It is shown in this paper that turbidity and particle counting data is not normally distributed and that values derived by means of percentile analysis are more sensitive than using the mean plus standard deviations. Percentile analysis is able to produce alarms for data that is clearly different from normal operation, enabling smaller deviations from the usual to be identified. The values derived from one set of data are also shown to be appropriate for periods of around three months.
Improved ultraviolet spectrophotometric method for determination of nitrate in natural waters
Authors: Kishimoto N. , Somiya I. , Taniyama R.
Published: May 2018

An improved UV spectrophotometric method for determination of nitrate in natural waters was proposed and the determination accuracy of the method was discussed in this study. As a result of estimation of the proposed method, adoption of 215 and 220 nm for detection of nitrate and interfering substances resulted in decreasing standard error to about a half of that of a conventional spectrophotometric method. One of the reasons was thought that the coefficient of variation of relative absorbance of interfering substances (rs) at 215 nm was smaller and more stable than that at 275 nm, which was used in the conventional method. The other reason inferred was that most of the interfering substances absorbed UV light at wavelengths of 215 and 220 nm. Although rs has to be renewed when targeted water quality is under extreme conditions, the procedure of the proposed method is very simple, namely only measuring two UV absorbances of a filtrated sample, and more accurate than the conventional spectrophotometric method. Consequently, the proposed method is available for rapid determination of nitrate in natural waters.
Fenton process for the combined removal of iron and organic micropollutants in groundwater treatment
Authors: Ijpelaar G.F. , Groenendijk M. , Kruithof J.C. , Schippers J.C.
Published: May 2018

Fenton process, known as Advanced Oxidation Process for the degradation of organic pollutants in waste and drinking water, was studied for the combination of iron removal and pesticide control in anaerobic groundwater. The combined effect of aeration and rapid sand filtration, which are commonly applied in groundwater treatment, was studied in a pilot plant. Pesticide degradation was performed on laboratory scale. It was found that addition of 2 mg/L H2O2 prior to aeration improved the removal of iron without hindering the filtration processes of manganese removal and nitrification. Under these conditions, the laboratory-scale tests showed pesticide degradations of up to 80% (influent concentration 1.6-2.5 μg/L). Dosing 8.5 mg/L H2O2 all selected pesticides were converted more than 80%. However, this dose appeared to have an adverse effect on the removal of iron and manganese and the nitrification process. This is attributed to the presence of relatively high concentrations H2O2 in the water entering the rapid sand filter. By filtration AOC, formed during oxidation with the low H2O2 dose, was reduced from about 70 μg/L to about 15-20 μg Acetate-C/L. Bromate formation did not occur. Residual H2O2 varied from 0.1-0.2 mg/L (2 mg/L H2O2 dose) to 0.2-0.4 mg/L (8.5 mg/L H2O2 dose) which is higher than the proposed guideline of 0.019 mg/L.
A low cost technique of arsenic removal from drinking water by coagulation using ferric chloride salt and alum
Authors: Khan M.M.T. , Yamamoto K. , Ahmed M.F.
Published: May 2018

A variety of treatment processes have been used for arsenic removal from water. In a laboratory study using natural (tubewell) water, ferric chloride salt and alum were used, which are the most studied and widely used flocculents in water treatment due to their low price, comfortable availability and low risk usability. The solubility of arsenate(III) is much more than arsenite(V). Arsenate(III) was converted into arsenite(V) by proper oxidation using bleaching powder as an oxidizing agent before coagulation. The concentrations of ferric chloride salt and alum dose were varied from 10 mg/l to 200 mg/l, and pH was varied from 4 to 9. After intensive investigation, it was found that at pH 7 and for 100 mg/l to 125 mg/l dose of alum, the removal efficiency of arsenic and iron were around 82 to 86% and 92 to 95% respectively. Again, the optimum removal of arsenic and iron were around 90 to 93% and 97 to 100% respectively at pH 7 for 200 mg/l of ferric chloride salt. This research was carried out not only to observe the removal efficiency of arsenic, but also iron. Because most of the tubewells in Bangladesh, sometimes, contain higher amount of iron.
A sensitive, semi-quantitative direct PCR-RFLP assay for simultaneous detection of five Cryptosporidium species in treated drinking waters and mineral waters
Authors: Nichols R.A.B. , Paton C.A. , Campbell B.M. , Wastling J. , Smith H.V.
Published: May 2018

We describe a semi-quantitative PCR-RFLP method for detecting low densities of Cryptosporidium spp. oocysts present in final drinking water samples and natural mineral waters. UK Standard Operating Protocols were used to concentrate oocysts from drinking water samples. Oocysts were concentrated from mineral waters by membrane filtration. Cryptosporidium oocysts identified by epifluorescence microscopy on slides or filters were subjected to DNA extraction and PCR-RFLP analysis. Oocysts were disrupted by freeze-thawing in lysis buffer. Amplicons were readily detected from 2 to 5 intact oocysts on ethidium bromide stained gels following 1 round of PCR. DNA extracted from C. parvum, C. muris, C. baileyi, human-derived C. meleagridis, and C. felis were used to confirm species identity by PCR-RFLP following simultaneous digestion with DraI and VspI.
Proficiency testing of Cryptosporidium and Giardia analyses - an Australian case study
Authors: Roser D. , Ashbolt N. , Ongerth J. , Vesey G.
Published: May 2018

An inter-laboratory proficiency trial was undertaken as a prelude to a survey of Australian drinking source waters for Cryptosporidium and Giardia oo/cysts. Specific aims included measuring the recovery of protozoan control material from representative source waters, identifying laboratory errors and assessing the utility of pre-stained reference oo/cysts. Five experienced laboratories were provided with coded vials containing oo/cysts or blanks for spiking 10 L water samples (11 replicate environmental, 5 filtered) or to be analysed directly (16 Count Control vials). Each laboratory reported both their standard counts and details of how each oo/cyst image was interpreted and confirmed. A sixth laboratory provided flow cytometry prepared seed material and reference analyses. Average recoveries for 10 L samples ranged from 0-67% and 0-72%, for environmental and filtered tap water respectively, depending on laboratory and sample type. The best performing laboratory obtained high recoveries, ranging from 45% to 66% for tap water and 63% to 81% for environmental water. Nonetheless, recovery from tap water and environmental sample analysed simultaneously by the same laboratory could differ markedly (1% v. 48% in one case). Poor recovery and false positives were encountered despite the experience of the participants. Inconsistencies in reporting were introduced by the different procedures for confirming oocysts and cysts. The trial showed that obtaining reliable estimates of environmental protozoan loads is still a concern for water managers.
Cryptosporidiosis and hotel swimming pools - a multifaceted challenge
Authors: Cartwright R.Y. , Colbourne J.S.
Published: May 2018

An outbreak of cryptosporidium infection affected at least 172 British tourists who had stayed at a family hotel in a Mediterranean resort. Recognition of the outbreak came from non-official sources. In the absence of any meaningful investigations by the public health authorities of both the countries, a tour operator undertook an investigation. The epidemiological studies were restricted but it was concluded that the outbreak was associated with contaminated swimming pool water at the hotel. The initial source of contamination was most probably a hotel guest who was excreting cryptosporidium oocysts. Examination of the water treatment system revealed some deficiencies in the sand filters but the effect on the course of the outbreak could not be determined. Although the media in the filters was thoroughly cleaned and the filters refreshed, oocysts could still be detected in pool water and further cases occurred. The challenges of an outbreak involving more than one country and the measures necessary to reduce the risks of cryptosporidium infections associated with hotel swimming pools are discussed.
Using turbidity and particle counts to monitor Cryptosporidium removals by filters
Authors: Huck P.M. , Coffey B.M. , Anderson W.B. , Emelko M.B. , Maurizio D.D. , Slawson R.M. , Douglas I.P. , Jasim S.Y. , O'Melia C.R.
Published: May 2018

Physicochemical removal of protozoan pathogens is receiving increased attention because of the difficulty of chemically inactivating these organisms, particularly Cryptosporidium parvum. Most studies that have examined the removal of these and other pathogens by filtration have been conducted under steady-state conditions with optimized pre-treatment. The research on which this paper is based evaluated the removal of Cryptosporidium and surrogates at various points in the filter cycle and under non-optimal conditions, at several pilot plants. The focus of this paper is on the relationship between removals of Cryptosporidium, and turbidity and particle counts. Under stable or optimal operating conditions all pilot plants produced similar low filter effluent turbidity and particle counts. Average Cryptosporidium removal varied among locations, however, by more than two log units. Cryptosporidium removal was impaired under all of the non-optimal conditions. Particle and turbidity performance was also worse, but the relationship of these parameters to Cryptosporidium removal varied. Particle counts show greater promise than turbidity as a tool to monitor filter performance in real time for possible deterioration in Cryptosporidium removal capability.
C. parvum in Melbourne's catchments: investigating prevalence and developing high-resolution molecular detection tools
Authors: Haydon S. , Zhu X. , Hellier K. , Gasser R.B.
Published: May 2018

The Melbourne Water Corporation has funded the University of Melbourne Veterinary School to study the prevalence of Cryptosporidium and Giardia in animals in water catchment areas of Melbourne and to establish molecular tools for the identification of the parasite to the species and strain levels. In a first epidemiological survey Cryptosporidium was found in high prevalence (17 of 24 species examined; n = 490), whereas Giardia was detected in two animals. A polymerase chain reaction (PCR)-based mutation scanning technique was established for identification of C. parvum to the strain level from oocyst isolates. This so-called single strand conformation polymorphism (SSCP) technique allows high-resolution analysis of genetic variability within and between populations of C. parvum. In a blind test, SSCP genotyping of 23 DNA samples representing C. parvum from different host and geographical regions demonstrated that the method could correctly type samples identified previously using a range of other methods, and displayed higher levels of sequence variability compared with conventional approaches. Hence, the method provides a powerful epidemiological tool for diagnosis as well as for identifying the source of waterborne outbreaks. Future molecular epidemiological surveys of cryptosporidosis/Cryptosporidium will be conducted together with Australian and European collaborators, with a particular emphasis on human cryptosporidosis.
Determination of cytotoxicity and invasiveness of heterotrophic plate count bacteria isolated from drinking water
Authors: Pavlov D. , de Wet C.M.E. , Grabow W.O.K. , Ehlers M.M.
Published: May 2018

Evidence has been presented that some heterotrophic bacteria often detected in drinking water supplies possess features associated with pathogenicity. This suggests that even the low numbers of heterotrophic bacteria considered acceptable by drinking water specifications may constitute a health risk, particularly to immunocompromised consumers. In this study, 339 bacteria were isolated at random from routine heterotrophic plate count (HPC) tests on selected drinking water supplies in South Africa. In a first screen for potentially pathogenic properties, 188 of the isolates (55.5%) displayed a- or b-haemolysis on blood agar. Further analysis of the haemolytic isolates for enzymes associated with virulence revealed the presence of chondroitinase (5.3%), coagulase (16.0%), DNase (60.6%), elastase (33.0%), fibrinolysin (53.7%), gelatinase (62.2%), hyaluronidase (21.3%), lecithinase (47.9%), lipase (54.8%) and proteinase (64.4%) of the isolates. No fluorescein or pyocyanin was detected in any of the isolates. Among the haemolytic isolates 68.6% were resistant to oxacillin (1 μg), 59.6% to penicillin G (2 units), 47.3% to penicillin G (10 units), 53.7% to ampicillin (10 μg) and 42.6% to ampicillin (25 μg). Cytotoxicity, invasiveness and adherence properties of the haemolytic isolates was determined on HEp-2 and Caco2 cell lines. Among the haemolytic isolates 96% were cytolytic on the HEp-2 cell line. All the haemolytic isolates adhered to HEp-2 and Caco2 cells but gram-negative isolates tended to adhere in larger numbers than gram-positive isolates. HEp-2 cells were invaded by 42% of the haemolytic isolates. Heterotrophic bacteria, which most frequently revealed the above features associated with pathogenicity included species of the following genera: Aeromonas, Acinetobacter, Aureobacterium, Bacillus, Klebsiella, Moraxella, Pseudomonas, Staphylococcus, Tsukamurella and Vibrio. The results obtained in this study support earlier indications that bacteria detected by routine heterotrophic plate counts on drinking water supplies may include bacteria associated with potentially pathogenic properties. The extent to which these bacteria in drinking water supplies may constitute a health risk remains to be investigated.
Automated event sampling for microbiological and related analytes in remote sites: a comprehensive system
Authors: Roser D. , Skinner J. , LeMaitre C. , Marshall L. , Baldwin J. , Billington K. , Kotz S. , Clarkson K. , Ashbolt N.
Published: May 2018

Pathogen concentrations are most often monitored during dry weather. Generally in Australia, however, loads mobilised during storms are of more concern. The filling of reservoirs commonly occurs from heavy rain events, and flood inputs may destabilise reservoir hydraulics leading to short-circuiting of contaminates to water supply off-takes. To capture storm events that can occur rapidly in remote locations at any time, automated sampling would seem appropriate. Unfortunately no commercial sampling system appears suitable for collecting multiple large volume samples along a hydrograph. We report here the development of an Event Sampling System (ESS) and associated resources, designed to address the special needs of microbiological sampling and varying event and site characteristics. The resultant ESSs consist of a standardised sampling module, enclosed in housings suited to different circumstances that is currently being field tested at six sites. Sampling module components include ISCO samplers modified to collect 24 ten litre ambient and 24 one litre refrigerated samples at remote sites along with in situ stream data. Essential to this hardware are sample collection and ESS management protocols covering issues such as storm warning, collection team mobilisation, laboratory coordination, ESS commissioning and maintenance. Some issues remain to be addressed, hence the resulting ESSs are seen as prototypes in the development of standardised storm-event based microbiological sampling well suited to remote locations.
International Report: Health-related water microbiology
Authors: Hunter P.R.
Published: May 2018

This report summarises the reports on health-related water microbiology of a number of countries. Although this is supposed to be an international report, only some 18 countries have submitted reports, all but five of which were European. There were no reports submitted from the Americas and few from African or Asian countries. These omissions are particularly notable when considering the fact that the largest burden of waterborne disease falls on the populations of these continents.
The spectral UV sensitivity of microorganisms used in biodosimetry
Authors: Cabaj A. , Sommer R. , Pribil W. , Haider T.
Published: May 2018

Biodosimetry, that is the application of microorganisms for the measurement of radiation, is already in wide use in the field of UV disinfection. The measurement of the mean fluence in flow-through systems with a biodosimeter (microorganisms with calibrated UV sensitivity) results in the Reduction Equivalent Fluence (REF). In the case of quasi monochromatic radiation (mercury low pressure lamp, 253.7 nm), the flow pattern of the water through the inhomogeneous radiation field, together with some other parameters, strongly influences the REF but the spectral sensitivity of the biodosimeter plays no role. If microorganisms with shouldered survival curves are used as biodosimeters two parameters (k and d) are necessary to describe their survival curves. In general, both parameters are wavelength dependent and the functions k(λ) and d(λ) must be known if medium pressure mercury lamps are used, which emit polychromatic UV radiation. The knowledge of k(λ) also is necessary for selecting an appropriate UV sensor which controls the function of the UV lamps during the operation of the disinfection plant. In literature many different spectral sensitivity curves were published but they all differ somehow. The functions k(λ) and d(λ) were measured for spores of Bacillus subtilis ATCC 6633 in using quasi-monochromatic UV radiation and the results were tested in using polychromatic UV radiation.
A probability model for burst risk studies of water mains
Authors: Ta C.T.
Published: May 2018

A logistic model was used for burst risk studies. The model is applied to study burst risk of large (300 mm and greater) water mains in the London supply area. Many contributing factors were included and represented as geographical information system (GIS) layers. Detailed sampling techniques were discussed. Using the available data, the burst probability function was found to correlate with pipe number density, pipe diameter, soil corrosivity and number of buses.
A comparison of methods and models for the analysis of water distribution pipe biofilms
Authors: Storey M.V. , Ashbolt N.J.
Published: May 2018

The suitability of three experimental devices: biofilm reactors™ (BR), biofilm exosamplers™ (BE), and modified robbins devices (MRD), for the analysis of water distribution pipe biofilms was examined in situ within an urban water distribution system (Rouse Hill Development Area, New South Wales). Stainless steel (ss) and unplasticized polyvinyl chloride (uPVC) coupons were conditioned with biofilm in each device for a period of 70 days. Biofilm removal techniques (sonication and stomaching) were evaluated and optimized for this study. A multiparametric quantification of biofilm biomass using total protein (NanoOrange™ protein determination) and carbohydrate (phenol-sulfuric assay) content, total number of bacterial cells (BacLight™ Live/Dead® Bacterial Viability Kit) and total number of heterotrophic bacteria (R2A plate counts) is proposed. The presence of biofilm-associated faecal indicator organisms (Enterococci, E. coli, somatic, F-RNA and B40-8 bacteriophages) was assayed for each biofilm homogenate. Variability both within and between biofilm devices was observed. Notwithstanding the shortcomings of the inherent heterogeneity observed with biofilm quantification, the relatively inexpensive biofilm devices were shown to yield reliable and comparable information on biofilm growth within an urban water distribution system. Furthermore, the multiparametric measurement of biofilm biomass was shown to provide a reliable and holistic quantification of distribution pipe biofilms.
Biofilm formation potentials in drinking waters treated by different advanced treatment processes
Authors: Okabe S. , Kokazi T. , Watanabe Y.
Published: May 2018

When biodegradable organic matter and other nutrients, such as ammonia and phosphorus, are not sufficiently removed during water treatment, bacteria may proliferate in the water distribution system. Bacterial regrowth deteriorates water quality (taste and odor), accelerates corrosion, and potentially increases the risk of microbial diseases. Therefore, this research was conducted to evaluate the impact of four different advanced water treatment processes, including biological treatments such as a rotating biofilm membrane reactor (RBMR) and a biological activated carbon (BAC) filter and ultrafiltration (UF), on reduction of nutrient levels and biofilm formation potentials of the treated water entering model distribution systems (annular reactors). Our results revealed that biological treatments significantly improved the “biostability” of water leaving from the treatment plant. On average, The RBMR and BAC filter reduced easily assimilable organic carbon (AOC) concentration by half when compared with conventional treatment (multi-media filtration; MF) and ultrafiltration (from 35-49 to 18-23 mg C L-1). Consequently, biofilm formation potential was reduced by a factor of 5 to 10 (from 3,200-5,100 to 490-710 pg ATP cm-2). With respect to “biostability” of water, ultrafiltration was less effective in reducing AOC concentrations. In addition, the impact of chlorine disinfection on biofilm accumulation and AOC levels in the distribution system were studied.
Water quality decay modelling in hydraulic pressure systems
Authors: Pirozzi F. , Pianese D. , d'Antonio G.
Published: May 2018

A mathematical model able to evaluate water quality variations in complex hydraulic pressure systems has been developed. The model consists of a set of mass balance equations for tanks, pipes and nodes. It has been applied to predict chlorine concentration inside a case-study water network described in literature by using different expressions of chlorine decay coefficients, obtained in laboratory tests and expressed as a function of the residence time of water in pipes, the initial chlorine concentration, the history and temperature of water. The results showed little variations of the chlorine concentrations and the need to calibrate the parameters of chlorine decay coefficients expressions on full scale hydraulic systems.
Benchmarking plant operation and instrumentation, control and automation in the wastewater industry
Authors: Ingildsen P. , Lant P. , Olsson G.
Published: May 2018

Benchmarking is an effective tool to compare the performance of full-scale wastewater treatment plant operation. In this study, 29 wastewater treatment plants from eight countries were surveyed with the aim of developing some key performance indicators, which may be used for benchmarking purposes. The level of utilisation of instrumentation, control and automation (ICA) has also been measured. The study of ICA utilisation revealed that on average only 23% of all sensors are used for online control. For most parameters, ICA is not the single dominant factor determining performance, although it is the factor that has the highest potential to improve performance. Eighty percent of the participating plants had implemented new control during the last five years leading to improvements in nitrogen and phosphorous removal, energy efficiency and ease of operation. The survey has quantified how “non-standardised” wastewater treatment plant operational practice is. Some simple key performance indicators are derived that relate the level of removal of ammonium, total nitrogen, phosphorous and suspended solids to the resources needed for their removal, i.e. volume, energy, organic matter and precipitation chemicals. Several indicators are suggested for each substance. The indicators show a great difference from the best to the poorest performance indicating that improvement potentials exist at many plants.
Co-operation of private water management sector with municipalities
Authors: Kyncl M.
Published: May 2018

After 1990 a gradual privatisation of the water and sewerage sector began in the Czech Republic as well as in other Central and Eastern European countries. State assets of public water pipelines and sewerage were transferred to towns and municipalities and joint stock companies were established. Two types of companies appeared Ð operational and ownership companies.

The first type is the operational company that operates the infrastructure assets of public water pipelines and sewerage. These assets stay in the ownership of municipalities. A long term operational contract is agreed that solves the relationship between the owners and operators.

The second type is the ownership company that directly owns the infrastructure assets of public water pipelines. Towns and municipalities in this case became shareholders of those companies. At the end of nineties, big international companies bought shares of both operational and ownership companies. Municipalities have to, by law, ensure the operation of public water pipelines. However, by the sale of shares they have lost a possibility to participate in decision making.

A question about future co-operation between towns and municipalities and ownership companies appears. An example of the North Moravian Water and Sewerage Works Company was used to describe a possible way of co-operation between a private company and the municipalities on whose territory the company operates. Contracts between the ownership company and particular municipalities were agreed. This solution turned out to be complicated, so the municipalities affiliated and established Water Management Association. The objective of the Association is to promote common interests of the municipalities in relation to the water company. A contract was agreed between the Water Management Association and the company about co-operation in the area of water tariff setting and public waterworks' development.
Innovative technology for reducing the finished water turbidity during sand filtration
Authors: Ebie K. , Lee J.H. , Azuma Y.
Published: May 2018

Sand filtration efficiency in treating low turbidity water greatly depends on the electrostatic interactions of both the surface of influent particles and that of sand grains or the deposited matter on the grains. This article describes two innovative filtration techniques to increase the particle separation efficiency: (1) coagulant-coated filter medium by enhancing the electrical potential of the surface of the filter medium; and (2) coagulant dosing in the influent by controlling the electrical potential of particles entering the filter layer. From the results of the various filtration experiments using a pilot plant, these two techniques were found to be very effective in reducing the effluent water turbidity during an initial stage of a filter run, and from the start to the end of a run, respectively. It should be also noted that the effectiveness of each method increased, as the amount of coagulant PACl used in the experiment increased. Moreover, in the filtration experiments using these two methods simultaneously, substantially higher removal efficiency of approximately 3 log (99.7%) was realized, resulting that the finished water turbidity was accordingly reduced to 0.004 mg/L.
Optimisation of conventional water treatment processes in Adelaide, South Australia
Authors: Holmes M. , Oemcke D.
Published: May 2018

Supplying drinking water in metropolitan Adelaide to meet contractual and Australian Drinking Water Guidelines is a challenge as source waters contain high concentrations of natural organic matter (NOM) that often exceed 10 mg/L dissolved organic carbon (DOC). The US EPA indicates that enhanced coagulation is the best available technology to control DOC in drinking water treatment plants. United Water has used enhanced coagulation at Metropolitan Adelaide WTPs since 1997 to improve water quality in the distribution system. NOM reduction has led to treated water with a lower chlorine demand allowing a greater residual penetration enabling improved bacteriological compliance. Disinfection by-product formation has also been controlled within the distribution system. Pathogen treatment barriers to remove Cryptosporidium and Giardia have been strengthened by adopting improved filter pre-treatment, enhanced coagulation and filter pre-chlorination to reduce particle breakthrough at all suitable WTPs.