bluuebunny/crossref_metadata_2025 huggingface dataset:
Operation of dual drinking and non-potable water networks in Paris: advantages and constraints
Authors: Nguyen B.
Published: May 2018

Paris is one of the very few cities in the world equipped with a dual network system: the drinking water network is duplicated by a totally independent non-potable water network which possesses its own means of production, storage and distribution pipes. In this second network there circulates untreated water characterized by pressure lower than that observed in the drinking water network. The fact that the constraints governing non-potable water are less than for drinking water is reflected in lower margins in relation to comparative production and storage capacity.

Non-potable water in Paris has existed for two centuries; it is very inexpensive and its use in large quantities forms part of the landscape to which Parisians are accustomed. 98% of non-potable water consumption are restricted to the uses of water linked to urban concentration for the comfort or safety of town dwellers: hydrants, fountains, street cleaning, watering of public gardens, flushing of the sewers etc. Therefore, the main consumer being the city of Paris, the operation of the non-potable water network differs in many ways from that applied to the drinking water network.

The economic context, the technical implications and the ecological repercussions of the use of non-potable water provide an alternative solution to the exclusive use of drinking water which seems to be efficient and attractive. This exceptional situation does not only offer advantages especially when one analyses the consequences for the network of waste water or the cost of maintaining a dual pipe network.
Some examples of water recycling in Australian urban environments: a step towards environmental sustainability
Authors: Gardner E.A.
Published: May 2018

This paper discusses the concepts and results from two contrasting types of water recycling initiatives in Australia. The first type of initiative is a centralised scheme based on local authorities recycling sewage effluent and/or stormwater in urban areas. A new urban subdivision in Queensland (Springfield) is provided as an example of such a centralised scheme, with uses ranging from dual reticulation, to public space irrigation, to urban lakes. The importance of strong public consultation and partnership is stressed for scheme success. A second example of a centralised scheme is an upmarket subdivision in Adelaide, South Australia (Mawson Lakes), where stormwater and recycled effluent are designed to supply in excess of 70% of the community's total water requirement. Scheme success is highly probable because of the ready adoption of innovative water supply alternatives by South Australians. The other type of initiative operates at a household scale (Healthy Home) and demonstrates that reinventing old ideas using new technologies can allow urban households to become largely self reliant for their potable and non-potable water needs, at least in high rainfall coastal areas. However, the cost effectiveness of this self reliance will require a substantial change in the sharing of savings from deferred public infrastructure costs. We include for comparison an analysis by Coombes et al. for the Lower Hunter region which clearly demonstrates that adoption of water sensitive urban design features, such as rainwater tanks in new developments, is not only more cost effective than traditional infrastructure solutions, but also allows the deferral of new urban water supply dams by the order of decades. We conclude the paper with the observation that advances in incorporating externalities into water development economics, the "trickle down" effect of new distributed technologies, and the growing desire by urban communities to live within the capacity of their regional ecosystems will probably ensure that reforms in the urban water and wastewater cycles will pioneer the way to genuinely sustainable and liveable urban communities in the near future. In short, the Ecological Footprint of urban development will be substantially reduced.
Costs of tertiary treatment of municipal wastewater by rapid sand filter with coagulants and UV
Authors: Heinonen-Tanski H. , Juntunen P. , Rajala R. , Haume E. , Niemelä A.
Published: May 2018

Municipal treated wastewater has been tertiary treated in a pilot-scale rapid sand filter. The filtration process was improved by using polyaluminium coagulants. The sand-filtered water was further treated with one or two UV reactors. The quality changes of wastewater were measured with transmittance, total phosphorus, soluble phosphorus, and somatic coliphages, FRNA-coliphages, FC, enterococci and fecal clostridia. Sand filtration alone without coagulants improved slightly some physico-chemical parameters and it had almost no effect on content of microorganisms. If coagulants were used, the filtration was more effective. The reductions were 88-98% for microbial groups and 80% for total phosphorus. The wastewater would meet the requirements for bathing waters (2,000 FC/100 ml, EU, 1976). UV further improved the hygiene level; this type of treated wastewater could be used for unrestricted irrigation (2.2 TC/100 ml, US.EPA 1992). The improvement was better if coagulants were used. The price for tertiary treatment (filtration + UV) would have been 0.036 Euro/m3 according to prices in 2001 in 22 Mm3/a. The investment cost needed for the filtration unit was 0.020 Euro/m3 (6%/15a). Filtration with coagulants is recommended in spite of its costs, since the low transmittance of unfiltered wastewater impairs the efficiency of the UV treatment.
Wastewater treatment and biomass production by slow rate systems using different plant species
Authors: Tzanakakis V.E. , Paranychianakis N.V. , Kyritsis S. , Angelakis A.N.
Published: May 2018

Natural treatment systems especially those based on land treatment, remain the only viable choice for wastewater treatment and reuse in small rural communities. In order to develop the appropriate technology required a slow rate (SR) systems were established at Skalani, a small village close to Iracklio, Greece. The SR systems were planted with four plant species eucalyptus, acacia, poplars and reeds to evaluate their effects on wastewater treatment and produced biomass. Systems performance were evaluated by monitoring BOD, COD, TSS, TKN, NH3-N, NO3-N, FC, and TC in soil solution and soil samples taken from the 15, 30 and 60 cm of the soil depth. The SR systems, displayed a good performance as regards COD BOD, TKN, NH3-N and bacteria removal (TC and FC). However, relatively increased values of NO3 were detected in 60 cm. In terms of plant species used, there were no significant differences in treatment efficiency among the four SR systems. Although, significant differences were observed in biomass production with acacia trees producing the greatest amount of biomass followed by reeds, while the lowest one produced by eucalyptous and poplar trees.
Die-off and retardation of Cryptosporidium spp. oocyst in loamy soil saturated with secondary effluent
Authors: Nasser A.M. , Huberman Z. , Zilberman A. , Greenfeld S.
Published: May 2018

This study was conducted to determine the comparative die-off of Giardia spp. cysts and Cryptosporidium spp. oocysts in loamy soil saturated with secondary effluent. The reduction efficiency of Cryptosporidium spp. oocysts in loamy soil columns was also determined. The die-off of Cryptosporidium spp. reached only 1 log after incubation for 20 days in loamy soil saturated with either deionized water or secondary effluent at room temperature (25°C), whereas a 2 log die-off was recorded for Giardia spp. cysts. Under the same test conditions, negligible die-off was observed for MS2 bacteriophage. Filtration of secondary effluent through 25-cm long loamy soil column resulted in the reduction of 99.99% of the seeded Cryptosporidium spp. oocysts, whereas negligible reduction was observed for MS2 bacteriophage. The highest percentage of Cryptosporidium spp. oocysts was recovered from the upper 3 cm of the soil column. Destruction of oocysts of Cryptosporidium spp. in the soil matrix can be attributed to high microbial activity. The results of this study indicate that oocysts of Cryptosporidium spp. might survive for prolonged period in saturated soil and in secondary effluent under moderate temperature conditions. However, oocysts are efficiently retained in loamy soil, which hinders their access to groundwater. Further studies are needed to clarify the infectivity state of the retained viable Cryptosporidium spp. in soil material.
Risk assessment in wastewater recycling and reuse
Authors: Salgot M. , Vergés C. , Angelakis A.N.
Published: May 2018

Wastewater recycling and reuse guidelines and/or regulations have been traditionally and exclusively based on the determination of bacterial indicators and nematode eggs presence. Nevertheless, it has been demonstrated that: (a) virus presence is not well established by bacterial indicators, (b) the viability of nematode eggs is not determined, (c) parasites' presence is not analysed, (d) behaviour of all pathogens once in the recycled water distribution systems and points of use is not known, (e) behaviour of pathogens in the environment is also not known, and (f) chemical risk is not assessed. Additionally, it is to consider that risk associated with reuse is directly related to the final contact host-pathogen, or to chemicals ingestion and contact with the human body. Consequently, future developments of laws, rules and regulations for wastewater recycling and reuse need to include: (a) more detailed biological and chemical analysis of recycled water and environment, (b) the development of tools for determining environmental impact of recycled water and by-products of recycling, (c) the establishment of tools guaranteeing a reduction of the host-pathogen contact, and (d) risk assessment and management mechanisms. Suggestions and recommendations are made on how to include all this items in the future legislative developments for wastewater recycling and reuse.
International guidelines for water recycling: microbiological considerations
Authors: Gerba C.P. , Rose J.B.
Published: May 2018

The World Health Organization and others have proposed international guidelines for the safe reuse of domestic wastewater. Treatment and microbial standards have been suggested with varying microbial water quality targets to suit local circumstances of affordability and health risks. However, it is important to recognize that universal application of bacterial standards for water quality assessment will not yield the same risks from microbial pathogens in reclaimed wastewater around the world. The concentration and types of pathogens in raw wastewater varies from one region of the world to another depending on the incidence in the community. This is influenced by the general hygiene, season, and per capita water use. Also, different treatment processes may be more effective in removing indicator bacteria and certain groups of pathogens than others. Proposed guidelines have also neglected the importance of water in the transmission of viral and bacterial diseases in developed countries and their impact on morbidity and mortality. Additional research is needed to better reduce the uncertainly of proposed guidelines for water recycling and to better define the risks associated to the exposed populations.
Multi-criteria decision support for annual rehabilitation programmes in drinking water networks
Authors: Baur R. , Le Gauffre P. , Sægrov S.
Published: May 2018

The selection of projects in the annual rehabilitation plan of a drinking water network requires the consideration of different aspects of existing deficiencies and expected improvements in the water supply system. With a field study of 12 water utilities in Europe, the objectives of drinking water network rehabilitation are identified. These objectives are assigned to a number of “points of view” that can be divided in two types: internal and external points of view. Internal points of view mainly affect the cost and the monetary benefits of rehabilitation measures for the utility. External benefits of rehabilitation result from a better hydraulic performance of the system, from improved system reliability or reduction of risks and therefore, they contribute to customer and third party satisfaction. Nine points of view are rendered more precisely by 17 criteria. The criteria are expressed by detailed cost functions, quantification of current deficiencies, assessment of risks or assessment of the pipe’s potential contribution to zonal problems. Examples are given of criteria definitions and their calculation for using them in procedures of aiding decisions. This paper is a report on ongoing work in the CARE-W European project.
Performance indicators for wastewater services - towards a manual of best practice
Authors: Matos R. , Cardoso A. , Duarte P. , Ashley R. , Molinari A. , Schulz A.
Published: May 2018

The aim of this paper is to present current work to develop a system of performance indicators (PI) for wastewater services undertaken under the auspices of IWA and coordinated by LNEC. Present day wastewater utilities manage their services and systems in an increasingly demanding and complex way. For this reason, it is important to support their work and decision processes with the best available tools in order to deliver services with the most effective and efficient performance. The paper focuses on proposed performance indicators (PIs) for wastewater services and on the main aspects of PI assessment. These are based on data related to: environmental, operational, personnel, physical, quality of service and economic and financial performance. Data are mostly made available through the various common-use information systems in the utilities. This IWA forum has been important not only for the dissemination of the work already developed but also as promotion of a wider discussion to enhance the final draft version of the IWA Manual of Best Practice due for publication in 2003.
Setting and evaluating customer service standards
Authors: Speers A. , Burn S. , Hatton MacDonald D. , Young M. , Syme G.
Published: May 2018

The Australian urban water industry has been substantially reformed over the past 20 years. Critical amongst these reforms has been the separation of operational and regulatory responsibilities. Under these arrangements the performance standards expected of water companies are specified by independent regulatory bodies or governments, and codified. Both regulators and water service providers have an interest in ensuring that regulatory standards are efficient and meet customer expectations, particularly as such standards can greatly affect the industry’s capital expenditure. A project has therefore been initiated to develop a framework for setting standards that are economically efficient, taking into account customer preferences. The project included development of methods to: identify customer preferences and means by which they would be measured;identify and evaluate the whole life cost of meeting standards for water continuity;value customers’ preferences, measure social costs associated with water interruptions and construct the overall cost benefit framework.

Water system continuity was the service chosen for testing the methodologies developed. We conclude that a viable methodological framework for setting customer service standards can be developed.
Managing trade waste: what should best practice look like?
Authors: Bissett R. , Green K.
Published: May 2018

Consideration of best practice in trade-waste management is timely, given the challenges that the water industry and its customers face in managing the triple bottom line so we can maximise sustainability of both our environment and business.

City West Water (CWW) is one of Australia’s largest providers of trade-waste disposal services. These services, and the associated trade-waste programmes we operate, are critical to managing the risks associated with trade waste, as well as facilitating the uptake of cleaner production and waste minimisation across industrial and commercial sectors. Providers of trade-waste services have direct contact with many waste generators. This is a unique platform for risk management and facilitation of cleaner production and waste minimisation. Consequently, trade-waste services and programmes are critical to the outworking of Government policies and commitments in relation to cleaner production, waste minimisation and sustainability, as well as to meeting the community’s expectations in relation to waste management. However, it is not these issues alone that should drive consideration of trade-waste management. We must consider these issues alongside the viability of economic development and employment and look for solutions that maximise the beneficial outcomes across all three dimensions of the triple bottom line.

This paper takes a look at the current trade-waste management environment, along with the existing legislative and policy frameworks. It then suggests what best practice trade-waste management should entail. It examines key issues and drivers, elements of an effective strategy, roles and responsibilities, resource requirements, challenges/obstacles and solutions, and performance measurement and how it should be communicated.
Computerised human resource planning and management system (HRPMS) for water services institutions
Authors: Johnson E. , Mjoli N.
Published: May 2018

The aim of this project was the development of computerised management systems for water utilities that can facilitate an increase in productivity while compensating to a certain degree for shortages of middle and high-level manpower. These are common requirements in developing countries.

The enhancement of knowledge using a computerised human resource planning system specifically for water services institutions can be achieved through the incorporation of human resource modeling techniques. The first phase of the project involved an extensive literature survey and development of version 1 of the software after limited exposure of the demonstration software to various stakeholders. An enhanced version 2 of the software was developed from the feedback received from various users through pilot studies and presentations. The development of the computerised Human Resource Planning and Management System (HRPMS) assists managers to undertake human resource planning of water services institutions.
Long-term behaviour of UF membranes treating surface water
Authors: Lipp P. , Baldauf G. , Schmitt A. , Theis B.
Published: May 2018

Since 1999 a UF plant with a mean throughput of 1.3 ML/d has been in operation treating surface water from a reservoir and springwater for drinking water supply. A three-year DVGW (German Water Works Association) research project accompanies the operation in order to gather data of the membranes' life time, their operational efficiency, the dependence of transmembrane pressure (TMP) on raw water quality (e.g. turbidity, particle count, concentrations of algae, natural organic matter) and the waste water demand. During operation TMP increased with increasing raw water turbidity and algae content and decreasing temperature as expected. Waste water demand has been minimised by decreasing the backwash frequency. A chemical cleaning showed not much effect with regard to TMP although waste water contained rather high amounts of suspended solids and dissolved organic matter. Bubble test for integrity showed that almost all membranes were still integral.
Potential cost reduction of seawater desalination
Authors: Glueckstern P. , Priel M.
Published: May 2018

The last four years had been witnessing dramatic developments and large cost reduction in the cost of desalinated water produced by large seawater reverse osmosis (SWRO) plants. First in the Eilat 10,000 m3/day plant, followed by the Tampa Bay, Florida project and more recently, by the Larnaca, Cyprus project. The real dramatic decrease relates to the Ashkelon large SWRO plant (in erection phase) where a sensational cost of about “half a US dollar” was reported. The reduced cost has become possible thanks to many factors: improved technology in pretreatment and reverse osmosis membranes, reduced energy consumption, lower interest rates and economics of scale. In this paper the evolution of water cost reduction in SWRO systems in the last decade is analyzed and is used as a basis for projection of further developments and cost reduction. Special attention is given to the new desalinated water standards such as reduced chloride and boron content, imposing an additional cost that can eventually be reduced by using more efficient reverse osmosis membranes and by implementing an improved boron removal technology. Due to these and to other developments a further 20% reduction in desalinated water cost will eventually be realized in the current decade.
Virus removal by ceramic membrane microfiltration with coagulation pretreatment
Authors: Matsui Y. , Matsushita T. , Inoue T. , Yamamoto M. , Hayashi Y. , Yonekawa H. , Tsutsumi Y.
Published: May 2018

The performance and mechanism of virus removal by microfiltration with coagulation pretreatment were investigated. We confirmed the unexpectedly high performance of virus removal for two types of ceramic membrane system: a positive pressure-driven dead-end filtration with inside-out configuration and a vacuum pressure-driven dead-end immersed filtration with outside-in configuration. Virus removals by both systems were more than 7 logs, although the size of the tested Qβ virus (23 nm) was much smaller than the membrane nominal pore size of 100 nm. The virus inactivation by the addition of the coagulant (PACl) and the virus adsorption onto the floc retained on the membrane surface mainly contributed the virus removal. No virus accumulation in the retentate was observed, possibly due to the virus inactivation by the coagulant.
Monitoring of biofilms in technical systems - a crucial component of advanced anti-fouling strategies
Authors: Flemming H.-C. , Tamachkiarow A.
Published: May 2018

“Biofouling” is a biofilm problem which is operationally defined. It applies to biofilms which exceed a given threshold of interference. If this is the case, countermeasures are taken. However, conventional antifouling strategies are hampered by some intrinsic problems which can identified as follows: (1) there are no early warning systems, (2) detection of biofouling is not performed on surfaces but by analysis of water samples which will not indicate site or extent of biofilms, (3) disinfection is misunderstood as cleaning, (4) nutrients are not limited although they must be considered as potential fouling biomass, and (5) the efficacy of countermeasures is performed by process performance or product quality. Avoiding mistakes 1–3 and 5 requires monitoring systems which provide relevant information on line, in situ, in real time, non-destructively and suitable for computer-aided automatization. Sample removal, staining or other secondary procedures should not be necessary. A suitable monitoring device is the fibre optical sensor. It consists of a measuring head integrated into the surface to be monitored and contains a sending and a reading optical fibre. If material is deposited on the tip of the fibres, light emitted from the sending fibre will be scattered back by particles and collected by the reading fibre. Increasing deposit accumulation results in an increasing signal of backscattered light. This sensor has been successfully integrated into a water piping system and responded quantitatively to build up and removal of deposits. Under conditions in which the particles were represented by bacteria, a calibration was performed. A stable signal could be acquired above a cell density of 105 cells cm-2. The system is, in principle, suitable to be integrated into membrane modules at representative locations.
Identification and control of fouling of low-pressure (MF and UF) membranes by drinking-water natural organic matter
Authors: Lee N. , Amy G. , Habarou H. , Schrotter J.C.
Published: May 2018

Natural organic matter (NOM) is responsible for organic fouling during membrane filtration. Flux decline can be affected by the characteristics of the NOM and its interaction with membranes and their associated properties. The results showed that serious flux decline observed for MF membranes may be caused by pore blockage associated with large (macromolecular) hydrophilic molecules. In the case of UF membranes, flux decline may be caused by sequential or simultaneous processes such as cake/gel formation with large (macromolecular) molecules and pore blockage with relatively smaller molecules during filtration. The flux decline tests with representative macromolecules showed that fouling was affected more by the physical characteristics (e.g. size and structure (shape)) of foulants than the characteristics (e.g. hydrophilicity) of foulants.
Application of UF/NF for the treatment of CIP (cleaning in place) rinsing waters: case study in a liquid detergent production plant
Authors: Forstmeier M. , Schipolowski T. , Goers B. , Wozny G.
Published: May 2018

In this paper the applicability of ultrafiltration and nanofiltration for the treatment of rinsing water in a liquid detergent plant has been investigated. Suitable membranes have been found in a membrane screening with flat sheet material, pilot experiments with industrial spiral wound modules under realistic conditions have shown the membranes' potential for reducing the COD load in the wastewater by up to 96%. Finally an optimum membrane plant structure has been derived by mixed integer nonlinear programming optimisation based on the experimental results. The membrane plant has been integrated into a model of the water network according to the concept for retrofit optimization of water networks strategy.
Nanofiltration of endocrine disrupting compounds
Authors: Gallenkemper M. , Wintgens T. , Melin T.
Published: May 2018

Endocrine disrupting compounds can affect the hormone system in organisms. A wide range of endocrine disrupters were found in sewage and effluents of municipal wastewater treatment plants. Toxicological evaluations indicate that conventional wastewater treatment plants are not able to remove these substances sufficiently before disposing effluent into the environment. Membrane technology, which is proving to be an effective barrier to these substances, is the subject of this research. Nanofiltration provides high quality permeates in water and wastewater treatment. Eleven different nanofiltration membranes were tested in the laboratory set-up. The observed retention for nonylphenol (NP) and bisphenol A (BPA) ranged between 70% and 100%. The contact angle is an indicator for the hydrophobicity of a membrane, whose influence on the permeability and retention of NP was evident. The retention of BPA was found to be inversely proportional to the membrane permeability.
A comparison of laboratory and pilot plant experiments on the combination of flocculation/ultrafiltration for direct potable water treatment of river water
Authors: Lerch A. , Hagmeyer G. , Gimbel R. , Fehn J.
Published: May 2018

A direct treatment of river waters with ultrafiltration is not yet realised in larger scales due to considerable fouling and scaling effects caused by water contaminants on the membranes surface under those circumstances. Therefore, the deposits on the membrane cannot be eliminated extensively by conventional backwashing. An extensive detachment of the formed layers while backwashing is desired to achieve cost advantages when using the process combination flocculation/ultrafiltration for the direct treatment of surface waters. Hence, pilot and laboratory plant experiments were carried out while dosing different coagulants at different pH-values with different concentrations of the coagulant to investigate their influence on the build-up of the coating layers. The experiments described here were focused on the following questions. Firstly, how do coagulation and flocculation conditions influence the performance of the treatment combination flocculation/ultrafiltration and which coagulant is best? Secondly, does a good operational performance of the combination flocculation/ultrafiltration at laboratory scale coincide with good operational performances at the pilot plant or does the presence of dissolved organic carbon (DOC) in the raw water decrease the performance significantly? Thirdly, does a good operational performance coincide with an extensive reduction of DOC, or humic substances, respectively?
Bio-hydrogen production from wastewater
Authors: Fang H.H.P. , Liu H. , Zhang T.
Published: May 2018

The technically feasibility of converting organic pollutants in wastewater into hydrogen by a continuous two-step process was demonstrated. Two carbohydrates, i.e. glucose and sucrose, in wastewater were respectively acidified by dark fermentation at pH 5.5 with 6–6.6 hours of hydraulic retention in a 3-l fermentor, producing an effluent containing mostly acetate and butyrate, and a methane-free biogas comprising mostly hydrogen. The acidified effluent was then further treated by photo fermentation for hydrogen production. The overall yield based on the substrate consumed was 31–32%, i.e. 17–18% for dark fermentation and 14% for photo fermentation. It was found that under certain dark fermentation conditions, hydrogen-producing sludge was agglutinated into granules, resulting in a higher biomass density and increased volumetric hydrogen production efficiency. DNA-based analysis of microbial communities revealed that the respective predominant bacteria were Clostridium in dark fermentation and Rhodobacter in photo fermentation. Further investigations are warranted, particularly, in areas such as improving reactor design, treating protein and lipid rich wastewaters, and studying sludge granulation mechanisms and controlling factors.
Hydrogen-based hollow-fiber membrane biofilm reactor (MBfR) for removing oxidized contaminants
Authors: Rittmann B.E. , Nerenberg R. , Lee K.-C. , Najm I. , Gillogly T.E. , Lehman G.E. , Adham S.S.
Published: May 2018

Research with a laboratory prototype and at the pilot scale documents that the hydrogen-based hollow-fiber Membrane-Biofilm Reactor (MBfR) is technically and economically feasible for reduction of nitrate and perchlorate. In the MBfR, H2 gas diffuses through the wall of a composite membrane, and an autotrophic biofilm naturally develops on the outside of the membrane, where the bacteria's electron acceptor is an oxidized contaminant (e.g., NO3− or ClO4−) supplied from the water. The hydrogen pressure to the hollow fibers is a key control parameter that can be adjusted rapidly and easily. For denitrification, partial nitrate removal often is acceptable, and the hydrogen pressure can be low to minimize the costs of H2 supply and the concentration of H2 in the effluent. When perchlorate must be reduced, full nitrate removal is essential, since NO3−-N above about 0.2 mg/L slows perchlorate reduction. Perchlorate reduction is sensitive to the hydrogen pressure, which underscores the critical role of H2 pressure for controlling process performance. Given that H2-oxidizing microorganisms have the potential to reduce many oxidized contaminants, we hypothesize that and are beginning to test how well the MBfR reduces bromate, selenate, chlorinated solvents, and other oxidized contaminants.
Giardia sp. cysts and Cryptosporidium spp. oocysts dynamics in southeast Brazil: occurrence in surface water and removal in water treatment processes
Authors: Bastos R.K.X. , Heller L. , Vieira M.B.M. , Brito L.A. , Bevilacqua P.D. , Nascimento L.E.
Published: May 2018

Raw water and filtered effluent of three drinking water treatment plants (WTP) at a town in Minas Gerais State, southeast Brazil, were monitored over a one-year period for Giardia, Cryptosporidium, microbiological and physical-chemical water quality indicators. High densities of Giardia and Cryptosporidium were detected in two source waters, ranging from 2.0–140 cysts/L and 4.0–510 oocysts/L. Giardia and Cryptosporidium (oo)cyst concentration was not consistently associated with most of the parameters analysed, turbidity being the most promising indicator. It also seems that Giardia and Cryptosporidium concentration was influenced by rainfall. Giardia cysts and Cryptosporidium oocysts were significantly associated in both waters, suggesting a similar pattern of occurrence and common contamination sources. In two of the three water treatment plants analyzed, Giardia and Cryptosporidium were detected in filtered effluents, also in high densities, ranging from 0.066 to 5.5 cysts/L and 0.066 to 13.2 oocysts/L, respectively. Statistical trials to associate protozoa and indicator removal failed in nearly all cases. Nevertheless, the results are interpreted as neither reaffirming nor negating the use of turbidity as a protozoa removal indicator.
Prioritisation of catchment management in the Sydney catchment - construction of a pathogen budget
Authors: Ferguson C.M. , Ashbolt N.J. , Deere D.A.
Published: May 2018

A methodology has been developed to apply the materials budget concept, used in sediment and nutrient studies, to construct a pathogen budget for drinking water catchments, taking into consideration pathogen origin, deposition, inactivation and movement within a catchment. These processes can be described in terms of stocks (pathogens) and flows (movement of stocks). In south-eastern Australia, the majority of pathogen loading to major tributaries was predicted to occur during and after high intensity rainfall events where in-stream resuspension was not of great relative importance. In contrast, during dry weather the transit time within the studied catchment was sufficiently long that in-stream processes became relatively important. Total pathogen unit (TPU) budgets were constructed for the parasitic protozoa Cryptosporidium and Giardia. This approach enables water utility managers to identify those catchment segments and processes that are contributing or removing the greatest load of pathogens, and thus where management options will be most effective. With improved knowledge of pathogen ecology this approach can be further refined to provide budgets of infectious pathogen units (IPU), more directed to public health risk endpoints.
Increased resistance of environmental anaerobic spores to inactivation by UV
Authors: Hijnen W.A.M. , van der Veer A.J. , Beerendonk E.F. , Medema G.J.
Published: May 2018

Water Company Europoort started a pilot plant (MP)UV study to determine the UV-fluence to meet the Dutch drinking water standards. The results of large volume sampling of this pilot plant demonstrated that environmental spores of sulphite-reducing clostridia (SSRC) were highly resistant against UV. With the pilot plant at a flow of 180 m3/h a challenge test was conducted to compare the susceptibility of environmental SSRC and lab-cultured spores of C. perfringens, MS2 bacteriophages and Bacillus subtilis. The latter was dosed as a biodosimeter with a calibrated UV253.7nm sensitivity to confirm the germicidal fluence. This test demonstrated that environmental SSRC were a factor of 1.6 more resistant against UV than the lab-cultured spores of C. perfringens. Furthermore, the results of these environmental SSRC indicated that they are more resistant to UV than other relevant micro-organisms for drinking water safety. Environmental SSRC calibrated with biodosimetry and determined with large volumes sampling is a potential parameter for on-site verification of the efficacy of UV-systems. Further research is necessary to determine to what extent the UV susceptibility of SSRC is consistent in the water and to find the cause of the increased resistance of environmental micro-organisms.
Discrimination of adenovirus types circulating in urban sewage and surface polluted waters in São Paulo city, Brazil
Authors: Santos F.M. , Vieira M.J. , Garrafa P. , Monezi T.A. , Pellizari V.H. , Hársi C.M. , Mehnert D.U.
Published: May 2018

Owing to frequent overflow of sewage-polluted creeks and rivers in São Paulo city, the population that lives in those surrounding areas is constantly exposed to a high risk of infection by many pathogens. Our aim was to evaluate the occurrence of human adenovirus, especially F species (HAdV-40 and HAdV-41), in sewage and creek water in São Paulo city. A total of 95 water samples were collected from July 1998 to June 1999 and from September 2000 to December 2001 at Sewage Pumping Station Edu Chaves and Creek Pirajussara. Four-litre samples were concentrated by a two-step procedure based on filtration through electropositive filter membrane and ultracentrifugation. Adenoviruses were detected in 69 samples (72.6%) after amplification of a sequence of the hexon gene by PCR. The discrimination of human adenovirus F was done by RFLP. A first screening was performed by restriction of PCR product with TaqI, followed by the discrimination of HAdV-40 and HAdV-41 by RsaI restriction. Sixty-two (89.8%) samples showed F species viruses. Among them, human adenovirus, serotype 41, was the most frequently detected in 17 (62.9%) out of 27 samples and serotype 40 was identified only in 7 (25.9%) samples. No seasonal distribution of adenoviruses was observed.
End use analysis: issues and lessons
Authors: White S. , Milne G. , Riedy C.
Published: May 2018

Methodologies for end use analysis have been developed by different researchers in the energy and water fields and in different areas in the world over the last 20 years. While there are core features associated with the methodologies and models used, the differences can provide insight into the ways that they might be improved, as well as the differences that may be required in different regions and when models are used for different purposes.

In addition to reviewing the field of end use analysis and appliance stock models, this paper will focus on two case studies. The first is the Sydney Water End Use Model, developed as part of the Sydney Water Least Cost Planning Study. This model has been developed and used to project the demand for water in Sydney over the next 20 years under business as usual scenario, as well as allow the projection of a number of scenarios which include major investment in water efficiency and effluent reuse programs as well as regulatory options to improve the efficiency of water using appliances in stalled in new buildings. Key features of the Sydney Water End Use Model include the fact that it takes into account the fact that the efficiency of toilets in Australia has a much larger range than (say) the US, in that the dual flush toilet was introduced in (to date) three stages. The model also accounts for projections of demographic and land use change which has been particularly dramatic in Sydney, particularly the movement to smaller occupancy rates in dwellings, and towards multi-family residential dwellings.

The second case study will demonstrate the linkages between end use modeling of energy using and water using appliances. A model of residential energy use in Australia has been developed as part of a research project to develop greenhouse abatement scenarios for Australia, and many of the appliances modeled overlap with the water end use model, including clothes washing machines, dishwashers, showerheads and taps. This more recent modeling exercise has revealed the importance of key assumptions in standard stock modeling techniques, and highlighted the need for earlier starting dates for stock modeling.

The process and results of these two case studies will be presented, and conclusions drawn about further improvements in end use analysis for both water and energy use. The linkage between the use of backcasting as a planning tool, and the use of end use analysis as a pre-requisite for the development of a demand management program is highlighted.
Watershed sources of disinfection byproduct precursors
Authors: Reckhow D.A. , Rees P.L.S. , Bryan D.
Published: May 2018

A series of field and laboratory investigations was conducted aimed at characterizing disinfection byproduct (DBP) precursor levels in the Wachusett Reservoir watershed. Samples were collected from spatial based and storm event sampling campaigns, as well as laboratory leaching experiments. These were analyzed for DOC, TOC and DBP precursors in an effort to characterize the changes in precursor levels and natural organic matter (NOM) character in this watershed. Based on these data, it was proposed that freshly leached NOM is relatively poor in DBP precursors due to the abundance of non-reactive carbohydrates. As these compounds undergo biodegradation within the watershed, the measured specific DBP precursor level rises, because the more reactive materials (e.g. lignins, phenolics) are also more persistent.
Use of ferrate pre-oxidation in enhancing the treatment of NOM-rich lake waters
Authors: Wei L. , Yong-Mei L.
Published: May 2018

Natural organic materials (NOMs) have a very strong influence on the stability of inorganic particles through interactions (e.g. adsorption, coating, and so on), and thus make the surface water with high NOM content difficult to be coagulated. In this study, standard jar tests and a pilot study were conducted to evaluate the effectiveness of ferrate pre-oxidation in enhancing the coagulation of NOM-rich lake water. A substantial reduction of residual turbidity after sedimentation and filtration was obtained by ferrate pre-oxidation at low dosage (1–5 mg L‒1 as K2FeO4). It was suggested that in order to maintain an acceptable residual turbidity, ferrate pre-oxidation can substantially reduce the dosage of coagulant. The improvement of water quality, as indicated by the reduction of color, DOC, iron, manganese, total bacteria, was observed to be similar in nature to the enhancement of residual turbidity. Formation of additional coagulant (Fe (III)) after decomposition was believed to be an important role of ferrate in enhancing coagulation. Ferrate could be employed in drinking water treatment by simple addition of ferrate solution just before coagulation.
The effect of dissolved natural organic matter on the rate of removal of ferrous iron in fresh waters
Authors: Ninh Pham A. , Rose A.L. , Feitz A.J. , Waite T.D.
Published: May 2018

The ease of removal of iron in water treatment is determined principally by the form of iron present. If iron is complexed to natural organic matter (NOM) and present in dissolved form, it is quite difficult to remove by conventional deep-bed filtration methods while if present as particulate iron oxyhydroxides it is readily removed. A major source of iron in reservoirs is the benthic sediments which, on becoming anoxic, release ferrous iron (Fe(II)) to the water column. This Fe(II) may either bind to NOM and be retained in dissolved form or may form inorganic hydroxyl complexes which oxidize to Fe(III) species which typically precipitate rapidly. In this paper, we report on studies of the kinetics of Fe(II) removal from solution in the presence and absence of the IHSS standard Suwannee River Fulvic Acid (SRFA). Oxidation of inorganic Fe(II) by oxygen is negligible at low pH but addition of organics changes the kinetics of removal of Fe(II) remarkably, reducing the half life of Fe(II) from hours to minutes. Increasing the concentration of SRFA also enhances the degree of Fe(II) removal. Experimental results obtained over a wide range of conditions are successfully described using a kinetic model which accounts for the transformations between Fe(II) and Fe(III) species.
Probing the mechanisms of NOM chlorination using fluorescence: formation of disinfection by-products in Alento River water
Authors: Fabbricino M. , Korshin G.V.
Published: May 2018

Experiments with Alento River water (a drinking water source in the province of Salerno, Italy) showed that considerable amounts of disinfection by-products, primarily chloroform and haloacetic acids, form in that water upon chlorination. The total yield of haloacetic acids was almost twice as high as that of chloroform. Chlorination also caused significant changes in the intensity of NOM fluorescence and the position of the emission band. To quantify the latter, the wavelength that corresponds to the position of the emission band at its half-intensity (λ0.5) was employed. Chlorination caused the λ0.5 values to decrease, while the THMs and HAAs concentrations were linearly correlated with the corresponding λ0.5 values. The strength of correlations between DBP concentrations and λ0.5 values indicates that the latter parameter can be employed in studies of DBP formation in drinking water.
Pilot study of water disinfection using solar concentrators in rural communities
Authors: Martín-Domínguez A. , Fonseca-Moreno O. , González-Herrera A. , Estrada-Gasca C.A. , Alarcón-Herrera M.T. , Martín-Domínguez I.R.
Published: May 2018

The efficiency of solar disinfection for the inactivation of Total Coliforms (TC) and Escherichia coli (EC) in drinking water was tested in two pilot studies performed in rural communities of the States of Chihuahua and Oaxaca, Mexico. The solar disinfection of drinking water (or photodisinfection) is an inexpensive alternative for easy application in rural communities. The study zones were selected mainly because they lack formal water supply systems and the population is forced to consume untreated water directly from rivers and shallow or artesian wells. The efficiency of the water disinfection process based on solar energy was determined in the dry and rainy seasons with water from the most contaminated sources in the study zones. The performed tests consisted of studying the effect of disinfecting water by direct exposure to sunlight during the whole day, with and without solar concentrators, in plastic bottles of commercial beverages. The three types of bottles used were transparent, partially painted black (one half of the bottle, along the longitudinal axis), and totally black. The study shows that, in these geographic zones, the available water must be disinfected before consumption, and disinfection efficiency can reach 100% through the use of solar radiation.
Performance of a small solar-powered hybrid membrane system for remote communities under varying feedwater salinities
Authors: Schäfer A.I. , Remy C. , Richards B.S.
Published: May 2018

An estimated 1 billion people are living both without access to clean drinking water or electricity. The small photovoltaic (PV)-powered hybrid membrane system described here is designed to address the plight of some of these people. PV and membrane technologies are chosen due to suitability for operation in remote and often harsh conditions. An ultrafiltration (UF) pre-treatment is included to remove bacteria and most pathogens, while a reverse osmosis (RO) or nanofiltration (NF) membrane desalinates the brackish feedwater. Several parameters were examined in order to optimise the system performance, including (i) feed salt concentration, (ii) operating pressure, (iii) system recovery, (iv) specific energy consumption (SEC, kWh/m3), and (v) salt retention. In addition, experiments were performed over a whole day to determine system performance under varying levels of solar radiation. The minimum SEC (relatively high due to the current single-pass mode of operation) varies from 5.5 kWh/m3 at a feed concentration of 1 g/L salt to 26 kWh/m3 at a feed concentration of 7.5 g/L salt, which is the upper limit of the system in terms of salt concentration.