bluuebunny/crossref_metadata_2025 huggingface dataset:
Shoalhaven Reclaimed Water Management Scheme: clever planning delivers bigger environmental benefits
Authors: Gould J. , Lee P. , Ryl J. , Mulligan B.
Published: May 2018

The Northern Shoalhaven REclaimed water Management Scheme (REMS) is one of the largest and most complex reclaimed water management schemes undertaken by an Australian water authority. REMS has been developed to beneficially re-use up to 80% of reclaimed water produced by six wastewater treatment plants in the Shoalhaven region. This paper outlines the process of Scheme development, which required effective integration of varied technical studies and extensive consultation with a diverse group of stakeholders. The process has delivered a scheme which exceeds authority, community and user objectives in terms of cost, environmental protection and operational efficiency. The consultative process implemented for scheme development and optimisation of the REMS concept are discussed as are operational challenges and scheme benefits.
Innovative fouling control by intermittent back-ozonation in metal membrane micro filtration system
Authors: Kim J.-O. , Somiya I.
Published: May 2018

The effect of intermittent back-ozonation for the keeping of high permeation flux in a metal membrane filtration system has been investigated. Internal back flushing with ozone gas (Back-ozonation) was more effective than other conventional fouling reduction methods. Through the experimental period with back-ozonation, average permeation flux showed more than 2.0 (m3/m2/day). Permeation flux was recovered up to 90% of initial flux with 0.27 (mgO3/cm3/cycle) of ozone injection rate. Among operational parameters, the degree of flux recovery was more sensitive to the change of ozone concentration (C) than ozone gas flow rate (Q) or injection time (T). Optimal operational values including ozone concentration (C), ozone gas flow rate (Q) and injection time (T) were 20.2 (mgO3/L), 3.1 (L/min) and 2.1 (min), respectively, for satisfying 90% of flux recovery. Intermittent back ozonation was thought to be an innovative and feasible technology for fouling reduction and the high permeation flux in a metal membrane filtration system.
A risk model for enteric virus accumulation and release from recycled water distribution pipe biofilms
Authors: Storey M.V. , Ashbolt N.J.
Published: May 2018

Screening-level quantitative microbial risk assessments (QMRA) undertaken to assess health risks associated with the reticulation of recycled water have identified distribution pipe biofilms and their ability to accumulate enteric and opportunistic pathogens as potential sources of public health concern. A simplistic model to assess human health risks associated with enteric virions (extracellular viruses) present in recycled water for domestic use was therefore developed. Recycled water biofilms formed on glass and stainless steel coupons in a laboratory-scale distribution system were challenged with model enteric virions (B40-8, MS-2 and FX174 bacteriophages). Approximately 1% of bacteriophages present in the adjacent bulk water was incorporated into 3 month-old biofilms and a persistent sub-population (0.01%) of the model enteric virions remained infectious in biofilms throughout an experimental period of 30 days. Significant potential for virions to accumulate within biofilms was therefore demonstrated, and indeed biofilm uptake could mask treatment failures assessed through analysis of the bulk water (infectious virions would not be detected after 1.5 km even if 10.L-1 virions present in treated effluent). Subsequent sloughing of biofilm into the bulk water phase could therefore release infective virions within mobilized aggregates of biofilm and infect susceptible consumers. During normal operating conditions (one virion in 100 L of water) sufficient virions may accumulate within distribution pipe biofilms that a 50% sloughing event could present a Pi (annual) of 1.9 × 10-4 for the consumption of 1 mL of water, exceeding the US-EPA benchmark of 10-4.
Minimum performance standards for showerheads in Australia: the benefits and the barriers
Authors: Day D. , White S.
Published: May 2018

This paper discusses the potential merits and opportunities of introducing national minimum performance standards (MPS) for water efficient appliances, in particular showerheads. At a national level the introduction of MPS for showerheads by 2005 is expected to result in a reduction in the demand for water by over 79 GL/annum by 2015. The reduction in energy consumption associated with reduced water heating needs by water efficient showerheads is 7.7 million GJ/annum, while greenhouse gas emissions will be reduced by 1.3 million tonnes CO2/annum, by 2015.

This initiative will generate benefits to an array of stakeholders. These benefits include: increased allocation of water for environmental flows, reduced demand on groundwater sources, reduced wastewater flows and associated pollution, and financial benefits to water utilities, particularly if the utility is experiencing water supply or wastewater treatment constraints. Regulation will also protect the investment (estimated to be of the order of $16 million) that a number of water utilities are making in incentive and retrofit programs.

The most effective form of regulation to achieve the greatest outcomes in terms of reducing water and energy consumption and greenhouse gas emissions is a regulation that controls the supply of showerheads on the basis of flow rate. The MPS being proposed is 9 L/minute, and regulation would involve mandatory labelling of showerheads and compliance with the AAA-rating. The legislative options and challenge of introducing such a requirement within the current regulatory environment are discussed.
Partial nitrification activated sludge operation as an appropriate nitrogen removal scheme for the Mediterranean region
Authors: Hatziconstantinou G.J. , Andreadakis A.D.
Published: May 2018

Wastewater Treatment Plants (WWTPs) operation under conventional fully nitrifying activated sludge BNR schemes, although favoured by the temperate climate conditions prevailing around the Mediterranean region, may prove quite inefficient in terms of both capital and O&M costs when recipient body characteristics do not pose similar requirements; especially more so, when treated effluents are intended for reuse in agriculture and nitrogen content may well serve as fertilizer. This paper presents some experimental evidence that single-reactor partial nitrification schemes, allowing for nitrogen removal to the extent needed under seasonally varying plant loading conditions and effluent quality requirements, and securing reliable and efficient plant operation, may be a more suitable alternative for similar cases.
Extensive reclamation technologies, assets for the development of water reuse in the Mediterranean
Authors: Brissaud F. , Xu P. , Auset M.
Published: May 2018

In the Mediterranean, the main water reuse application is and will long remain irrigation. Irrigation of public parks, landscape, golf courses, market gardening and orchards is expected to develop rapidly. Such uses require the microbial decontamination of reclaimed wastewater. Extensive reclamation technologies are well adapted to the Mediterranean context for their easy and cost effective O&M; however their ability to reliably meet health related standards have been questioned. The paper reviews the main factors of variations in the bacterial abatement provided by extensive treatment techniques - stabilisation reservoirs, ponds and infiltration percolation. Thanks to advances in the knowledge and modelling of disinfection mechanisms, the predictability of microbial decontamination by extensive technologies is being significantly improved; the development of better design tools leading to reliable treatments is foreseen. However, due to limitations in the microbial removal, extensive techniques cannot meet highly conservative requirements. Extensive techniques will play an important part in the development of water reuse and fresh water savings in the Mediterranean as far as water quality standards only aim at limiting health risks to an acceptable level.
Reclaimed water reuse in the Mediterranean region: some considerations on water resources, standards and bacterial re-growth phenomena
Authors: Nurizzo C.
Published: May 2018

Problems related to wastewater reclamation and reuse in the countries of the Mediterranean region are discussed with reference to growing conflicts among agriculture, tourism, cities and industries. All reuse options are strongly influenced by requested water quality, especially the microbiological one, and for this reason standards for reclaimed water have to be fixed having in mind both the safety of reuse and its practical and economical feasibility. The paper will discuss, as an example of a type of approach, also the regulations' evolution with reference to the Italian situation. Some considerations on the feasibility of current indicator bacteria will be done, making reference also to the bacterial re-growth potential associated with various disinfection agents and to the applicability of advanced methods capable to individuate partially damaged cells and therefore useful to a better evaluation of the possible re-growth phenomena.
Assessment of the impact of mains cleaning to improve distribution water quality
Authors: Vitanage D. , Copelin C. , Karunatilake N. , Vourtsanis T.
Published: May 2018

This paper outlines Sydney Water’s experience in implementing mains cleaning as part of an integrated approach to water quality improvement. Targeted flushing of water mains is generally used as a first approach to mains cleaning, while swabbing is used as a remedial action where flushing has failed to improve water quality performance. To show the benefits of flushing/swabbing two approaches were taken. The first approach looked at the quality of the discharge water, while the second looked at the compliance and operational data before and after mains cleaning. Using this data, the distribution systems were ranked in terms of water quality improvements. The rankings show that six of the ten Distribution Systems that received the most swabbing now rank in the top ten performers, while four of the ten Distribution Systems that received the most flushing now rank in the top ten performers. The discharge water was found to contain suspended solids, total coliforms, HPC20C, iron, aluminium, manganese and biofilm/biomass. Some coliform species were found to be similar to the bacteria found in compliance coliform failures. An integrated mains cleaning strategy that includes flushing, swabbing and water main rehabilitation is essential to prevent water quality deterioration in the distribution system.
Optimal water meter sizing and maintenance system (OSMS)
Authors: Johnson E.
Published: May 2018

Water meters operating outside their performance specifications can contribute to non-physical water losses as well as to financial losses of a water authority. The aim of this project was to develop and test a computerised system providing a continuum of methods for selecting water meters varying from pure theoretical to semi-empirical and then to a wholly empirical process. The theoretical process relies on water demands derived from local and international design codes and standards in the selection of new water meters for buildings or water management areas. The first estimate for the selection of a water meter can be based on both records of billing data as well as on theoretically determined peak and minimum water demands. Empirically measured water demand profiles can be processed and analysed by OSMS to establish the best match for a particular water meter’s specification. Field trials in South Africa and Brazil were instrumental in identifying additional features that enhanced the development of OSMS, as well as emphasised the usefulness of the software. A literature review and a pilot study indicate a previous trend of installing over-sized meters. Replacement meters that are optimally selected can finance the costs of such investments.
The assessment of biofilm community composition on plumbing materials in filtered and unfiltered water distribution systems
Authors: Critchley M.M. , Cromar N.J. , Fallowfield H.J.
Published: May 2018

Biofilms have been extensively characterised within drinking water distribution systems. However, the significance of materials on biofilm species diversity is not established. This study investigated the community composition of biofilms on plumbing materials receiving filtered and unfiltered water supplies. Biofilms were extracted from polybutylene, polyethylene, cross-linked polyethylene, unplasticised polyvinyl chloride and copper tubes in sampling rigs receiving Murray-Onkaparinga water before or after filtration. Biofilms were extracted and analysed for fatty acid composition using the FAME™ methodology. There were differences in the fatty acid profiles of biofilms and the respective water supplies, indicating differences in the attached and planktonic communities. The results also showed significant differences in the fatty acid profiles of biofilms on the polymer materials compared to copper, suggesting variations in biofilm populations on the different materials. The potential for materials to select for microbial populations has significant implications for the ecology of drinking water biofilms.
Generic monitoring tools for water characteristics assessment
Authors: Le Bonté S. , Pons M.-N. , Potier O. , Chanel S. , Baklouti M.
Published: May 2018

An adaptive principal component analysis applied to sets of data provided by global analytical methods (UV-visible spectra, buffer capacity curves, respirometric tests) is proposed as a generic procedure for on-line and fast characterization of wastewater. The data-mining procedure is able to deal with a large amount of information, takes into account the normal variations of wastewater composition related to human activity, and enables a rapid detection of abnormal situations such as the presence of toxic substances by comparison of the actual wastewater state with a continuously updated reference. The procedure has been validated on municipal wastewater.
The political economy of water reform feasibility in Australia
Authors: Isaac M.
Published: May 2018

Australia is experiencing the most dramatic and comprehensive reform of its water industry, placing it at the leading edge of water management internationally. A key feature of the reforms is the explicit linking of economic and environmental objectives: in that the reforms seek to improve environmental management of the nation’s river systems by increasing efficiency of water use via water markets. However, there is growing evidence to evince that water markets are failing to achieve environmental objectives. This paper uses the insights of economic sociology to analyse this failure, and argues that economic efficiency does not and will not guarantee environmental effectiveness because newly constructed water markets are embedded in existing social processes/industry structures and are permeated by existing power relations. For real environmental benefits to accrue, existing water markets must be seriously restructured. This paper explores the elements of such a restructure and suggests that it is unlikely to succeed without strong state action and coordinated policymaking, institutional reform, adjustment packages, significant community involvement, and the participation of the rural sector. Finally, it proposes that social capital could play a pivotal role in the restructuring of the Australian water industry.
Selective color removal nanofiltration membrane for the 7 mgd Irvine Ranch water treatment project
Authors: Bartels C.R. , Wilf M.
Published: May 2018

A new polyether sulfone membrane which was recently developed, has now been used for the purification of colored groundwater. This new nanofiltration membrane was developed to selectively remove organic material with molecular weight greater than 1,000 daltons, while passing most salts. This characteristic is ideal for applications which have low salinity, but high color or other organic compounds. This membrane differs from traditional polyamide RO membranes as it is chlorine tolerant and has a large negative surface charge. This makes it ideal for waters containing high organic levels. This membrane has been extensively pilot tested with other traditional nanofiltration membranes. The membrane had the best combination of high flux, high color removal and minimal hardness removal. As a result of these features the membrane was selected for a 27.8 ML (7.35 mgd) water treatment plant at the Irvine Ranch Water District. The full-scale plant contains about 1,300 pieces of 33.9 square metres (365 sq feet) spiral wound elements. The full-scale plant has been completed and start-up of the first train has been completed. The feed color units (CU) were in excess of 200 CU, while the permeate was less than 5 CU, which meets the requirement of the plant. This is one of the largest membrane plants designed to only remove color from the water.
Development of a new integrity testing system
Authors: van Hoof S.C.J.M. , Broens L. , Nahrstedt A. , Panglisch S. , Gimbel R.
Published: May 2018

As membrane filtration systems are more commonly used in the water treatment industry, the call for a reliable, fast and on-line integrity testing system becomes more urgent. Especially where membrane filtration is used in potable water production for the removal of pathogenic microorganisms, the integrity of such a system is of the utmost importance. Membrane integrity testing can be performed in a number of ways, where the pressure-hold or vacuum-hold test and the diffusive airflow test are well known. Although relatively widely applied in membrane plants worldwide, all of these methods exhibit major drawbacks like off-line testing and the lack of a direct relationship between the measured data and the removal efficiency (log-removal). To overcome the above mentioned drawbacks of conventional integrity testing systems, a new kind of integrity test, the Spiked Integrity Monitoring System or SIM®-System was developed by NORIT Membrane Technology in close co-operation with Water Supply Company North Holland and IWW Rhenish-Westphalian Institute for Water Research, which combines the accuracy of a challenge test with the speed of a pressure test, while keeping the system under test in operation.
Effect of ozonated water on membrane fouling
Authors: Plottu A. , Her N. , Houssais B. , Amy G. , Gatel D. , Cavard J.
Published: May 2018

Since 1999 the Mery-sur-Oise plant has operated using two processes in parallel: one, a membrane process using nanofiltration, and the other, a conventional biological process. For operational flexibility, it is desired to be able to transfer some of the sand-filtered ozonated water from the biological process to the membranes. Before carrying out this transfer, it was important to assess the role of ozonation on membrane fouling, by comparing the effects of ozonated water (SFOW) with non-ozonated water (SFW). Tests were performed, in spring and fall 2001, in a pilot unit comprising two nanofiltration lines in parallel. The first test emphasized the essential role of the pre-filter placed upstream of the membranes. This latter - supplied with ozonated water – released particles when saturated, linked to changes in the feed water quality. Despite very frequent pre-filter replacements, fouling proved to be greater for the membranes supplied by ozonated water. Even though the silt density index and total cell counts levels of SFOW were lower than SFW, ozonated water could increase membrane fouling. The action of ozone on the nature of organic matter appeared to be the main cause. Ozone modified the composition of natural organic matter, on one hand by reducing the hydrophobic fraction in favour of the hydrophilic fraction, which is harder for the membrane NF 200B to reject, and on the other hand by acting on the lyses of algal cells and the release of extracellular organic matter. The membrane autopsies confirmed that the deposit is essentially composed of organic matter. Images taken with a scanning electron microscope showed a more significant deposit for membranes fouled with SFOW. For the membrane fouled in spring, the images also revealed the presence of algae; for some, cells were lysed upon ozonation. HPSEC-UVA-DOC enabled the types of molecules to be identified according to size. Humic substances (1,000 to 5,000 daltons) and other low molecular weight components (400 to 600 daltons) represented a minor part of the fouling material with the major components being proteins (21,000 to 24,000 daltons). Also, humic substances were relatively more abundant in the membrane fouled with ozonated water in spring.
An in situ biofouling monitor for membrane systems
Authors: Kappelhof J.W.N.M. , Vrouwenvelder H.S. , Schaap M. , Kruithof J.C. , van der Kooij D. , Schippers J.C.
Published: May 2018

Biofouling is a frequently occurring fouling mechanism in membrane applications. Controlling this phenomenon is a challenge due to the difficulty of cleaning biofouling in spiral wound membrane elements. It is assumed that cleaning can be more efficient when biofouling is in an early stage of colonisation. Therefore a sensitive method has to be available for an early identification of biofouling. The present method, the measurement of the normalised pressure drop (NPD) is not specific for biofouling and is not very sensitive. In this research the feasibility of the specific oxygen consumption rate for detection of the activity of biofilms was investigated in membrane systems. The method has the advantages to be specific for active biomass, applicable in situ, non-destructive and more sensitive than NPD. Three experiments demonstrated that the measurement of the rate of oxygen consumption is potentially a simple, reliable method for the measurement of the active biomass in membrane systems. During one of the experiments the method illustrated the effect of cleaning and the regrowth of bacteria afterwards. The method will be further evaluated and standardized. The relation between the specific oxygen consumption rate and the condition of the biofilm, measured by autopsy of membrane elements, will be further explored. The ongoing research will result in an apparatus and procedure, to be used for biofouling identification during the operation of full-scale and pilot plants.
Combining lab results and full-scale plant experience for the optimisation of dead-end ultrafiltration - an integrated approach
Authors: Brügger A. , Melin T.
Published: May 2018

During the last four years a new cushion module has been commercialised for dead-end ultrafiltration in water treatment. However, system and operation mode optimisation is still subject to research and development activities. For dead-end ultrafiltration one of the key issues is the module flushing procedure. So far, analytical methods for the investigation of particular steps during module flushing are rare and optimisation in most cases relies on operating experience. This paper presents the optimisation of the airpulsing step as part of the module flushing procedure with an approach, which combines lab-scale experiments and analysis of full-scale plant operation. For this purpose a novel method for shear stress measurement has been developed and applied. The results have been utilised for the optimisation of a fullscale ultrafiltration unit for wastewater treatment plant effluent upgrade. After changing the module flushing parameters and thus enhancing the flushing efficiency it was possible to increase filtration performance.
Development of pre-coagulation and bio-filtration process for advanced treatment of sewage
Authors: Tsuno H. , Hidaka T. , Nakamoto M.
Published: May 2018

A pre-coagulation and bio-filtration process for advanced treatment of sewage is developed and experimentally discussed with a pilot plant. The bio-filtration unit consists of a denitrification filter, a nitrification filter with side stream to the denitrification filter, and a polishing filter with anoxic and aerobic parts. Concentrations of SS, T-CODCr, T-C-BOD, T-N and T-P in the effluent were stably kept at less than mg/L, 20 mg/L, 5 mg/L, 2 mg N/L and 0.2 mg P/L, respectively, and transparency at higher than 100 cm, under total hydraulic retention time (HRT) of 3.2 h in the bio-filtration parts. S-CODCr/NOx−-N ratio of higher than 12 mg COD/mg N is required to keep the remaining NOx−-N concentrations less than 1 mg N/L in the effluent from the denitrification filter. Methanol addition rate of higher than 4.5 mg COD/mg N is necessary to accomplish denitrification with the remaining NOx−-N of less than 0.5 mg N/L in the effluent from the polishing filter. Backwashing in each filter as well as methanol addition and aeration in the polishing filter were able to be operated successfully by the automatic control systems. Therefore this process is proved to be applicable to advanced treatment of sewage with easy maintenance.
Practical design of flocculator for new polymeric inorganic coagulant - PSI
Authors: Ohno K. , Uchiyama M. , Saito M. , Kamei T. , Magara Y.
Published: May 2018

Physical characteristics of flocs formed by new polymeric inorganic coagulant, polysilicato-iron coagulant (PSI) were investigated using kaolinite clay suspended water as test water. Floc density was determined by measuring floc settling velocity and spherical equivalent floc diameter. The floc density function proposed by Tambo and Watanabe could be applied to PSI. Flocs formed by PSI showed higher floc density than those formed by alum at the same floc size. Floc size distribution after the rapid mixing as also determined. PSI could produce well-grown flocs at the stirring speed of 300 rpm. Stirring at 300 rpm for 7 minutes, residual turbidity after 15 minute sedimentation became lower than rapid mixing at 120 rpm for 5 minutes followed by slow mixing at 40 rpm for 25 minutes. Flocs formed by PSI was much stronger than those formed by alum. Using the data obtained, the design parameters of flocculator by use of PSI were estimated following Tambo and WatanabeÕs procedure. According to the estimation, it was suggested that rapid mixing process alone can make well-grown flocs and slow mixing process, which is essential for the conventional water purification system using aluminium coagulants, can be eliminated by use of PSI.
Disinfection by-products in US drinking waters: past, present and future
Authors: Singer P.C.
Published: May 2018

Disinfection by-products have been regulated in finished drinking waters in the United States since 1979. The original regulations dealt only with trihalomethanes, but more recent rules also address haloacetic acids. Compliance with these regulations has traditionally been based on a running annual average of quarterly measurements of disinfection by-products in the distribution system and on concerns about adverse health effects associated with chronic exposure to these by-products. More recently, concerns have also been focused on short-term exposure and acute reproductive and developmental adverse health effects. Additionally, while compliance has previously been based on disinfection by-product levels in samples collected primarily at locations with average distribution system residence times, forthcoming regulations will base compliance on disinfection by-product levels in samples collected at locations with maximum trihalomethane and haloacetic acid concentrations. Moreover, instead of the maximum contaminant levels applying to the annual average of all distribution system samples, the new rules will require that the annual average of the regulated disinfection by-product concentrations at each monitoring location be less than their respective maximum contaminant levels. This paper reviews the evolution of disinfection by-product regulations in the United States and on the rationale behind these regulations.
Salmonella: relations with indicators in recreational waters affected by sewage discharges
Authors: Efstratiou M.A.
Published: May 2018

Densities of bacterial indicators of marine faecal pollution were compared, in coastal areas affected by sewage and river discharges, with Salmonella spp. t-tests comparing numbers of TC, FC and FS in samples positive and negative for Salmonella showed a good association between TC and FC (p significant at 0.006 and 0.034 respectively) and the pathogen. The levels of all three indicators in the guide standards of the EU Bathing Water Quality Directive predict absence of Salmonella. The Imperative standards of the directive do not. The conclusion is reached that if sewage works discharges into the watercourse effluent with low indicator counts the risk of Salmonella in the water will be minimal.
Applications of in-vitro cell culture for measuring infectivity and inactivation of Cryptosporidium parvum
Authors: Rochelle P.A.
Published: May 2018

Cryptosporidium parvum presents a significant problem for the water industry and public health officials because of its prevalence in sources of drinking water and its resistance to chlorine-based disinfectants; there is an urgent need for alternative, more effective disinfection strategies. Therefore, developing and evaluating methods for assessing the infectivity and inactivation of C. parvum oocysts are of paramount importance. Infectivity assays based on in-vitro cell culture have been developed as alternatives to human and animal-based assays to overcome ethical, cost, and practicality issues. Data obtained over a two-year period with an HCT-8 cell culture/RT-PCR infectivity assay generated an ID50 of 99 oocysts (95% CI: 84-117) and demonstrated that the cell culture assay was equivalent to the standard CD-1 mouse model for measuring infectivity of C. parvum oocysts. Aggregate data generated over two years using the HCT-8 cell culture/RT-PCR assay to measure UV disinfection of C. parvum demonstrated that 2.4 mJ/cm2 and 4.9 mJ/cm2 were necessary to achieve 1-log10 and 2-log10 inactivation, respectively. This work demonstrated that an HCT-8 cell culture-based infectivity coupled with RT-PCR for detecting C. parvum infections is a practical tool that can provide valuable information about the efficacy of disinfectants and the infectivity of oocysts in environmental waters.
Water demand management - philosophy or implementation?
Authors: Buckle J.S.
Published: May 2018

This paper describes the introduction of water demand management in the southern African context. Originally a response to drought conditions, water demand management is now a key element in Rand Water's strategy of water cycle management - a mix of interventions that (holistically and continuously) keep the water industry viable and sustainable. This experience points to awareness and community education programmes being an essential companion to the technical interventions such as leakage reduction measures.
Water efficiency in Austin, Texas 1983-2003: an historical perspective
Authors: Gregg T. , Strub D.
Published: May 2018

Austin implemented the first elements of its water efficiency program in 1983 and has continued to add additional elements to its program up to the current time. Each added element has been aimed at correcting a particular type of inefficient water use. This paper examines the evolution of the programs that have been implemented in Austin and the impact that these programs have achieved. In addition, several programs will be discussed that were considered for implementation but were rejected.
Characterization of the changes in polarity of natural organic matter using solid-phase extraction: introducing the NOM polarity rapid assessment method (NOM-PRAM)
Authors: Rosario-Ortiz F.L. , Kozawa K. , Al-Samarrai H.N. , Gerringer F.W. , Gabelich C.J. , Suffet I.H.
Published: May 2018

A new technique has been developed to quickly monitor the changes in polarity of aqueous natural organic matter (NOM) using solid-phase extraction (SPE) cartridges. This paper introduces the NOM polarity rapid assessment method (PRAM). The PRAM technique characterizes changes in NOM polarity by monitoring the breakthrough curves from different SPE cartridges at UV254. The SPE cartridges used in this study include a wide range of polarity from non-polar C-18 materials to anion exchangers. Each individual cartridge run takes 10 minutes and requires about 15 ml of sample. The collected water sample matrix is not changed, i.e. all PRAM analyses were done under ambient conditions on the original sample. Polarity evaluation is completed without the sample being exposed to changes in sample conditions, such as pH, solvent extraction, sequential evaporations or freeze-drying. This technique was able to monitor the weekly changes in NOM polarity entering a water treatment plant and compares the effects of different water treatment processes on this material.
A study on the fouling phenomena of a microfiltration membrane
Authors: Yeh H.-H. , Wang W.-H.
Published: May 2018

The utilization of membrane processes for drinking water treatment has become more popular. However, fouling by source water probably is the major factor prohibits its widespread application. In this research, the fouling phenomena of a microfiltration (MF) membrane were studied. The interactions among colloidal particles, calcium ion, and dissolved organics, such as salicylic acid, humic acid, and alginic acid, on MF fouling were focused. A lab-scale single hollow fiber MF membrane, made of polyvinylidenefluoride (PVDF), module was used. The results show that, for single organic compound, the extent of fouling caused by humic acid was higher that of alginic acid. For the latter, the permeate flux decrease at lower pH was more significant than those at higher pH. For low MW salicylic acid, both rejection and flux decrease were minor. It seems that solubility have strong correlation with fouling rate. The higher the solubility is, the lower the fouling rate. For sole colloidal particle system, latex beads with diameter close to the pore size of MF membrane showed severe fouling. Adding Ca can aggregate the latex beads, and alleviate fouling. However, calcium ion also found to increase fouling of alginic acid on membrane under neutral or alkali pH condition, probably via charge neutralization and/or bridging. In conclusion, MF fouling seems to be strongly related to the type of organics, size of colloidal particles, and the existence of divalent ions, in the feed water.
Prevention of bromate formation by adsorption phase ozonation using high silica zeolites
Authors: Shiraishi K. , Fujita H. , Izumi J. , Fujii T. , Akiba M. , Sagehashi M. , Sakoda A.
Published: May 2018

The objectives of this work are to propose a novel ozonation process in adsorption phase using high silica zeolites and elucidate its advantages for simultaneous achievement of prevention of bromate formation and sufficiently high ozonation performance. Bromate is formed from bromide during ozonation under conventional conditions and needs to be reduced at least below a regulated concentration because of its considerable carcinogenicity. The ozonation of 2-methylisoborneol (2-MIB), a model Taste and Odor (T&O) chemical, has been studied in our process. It was known that 2-MIB is adsorbed onto high silica zeolite and oxidized with ozone rapidly in micropores. An adsorbent, named US-Y, in which the SiO2/Al2O3 ratio is 70, was the best candidate in this study in terms of adsorption of 2-MIB, decomposition of 2-MIB and prevention of bromate formation. Actually, bromate formation was not detected, while about seventy five percent of 2-MIB was decomposed with extremely low ozone concentration of 0.07 ppm and short retention time of 0.2 min in the presence of US-Y. Its applicability for the treatment of natural water containing natural organic matters (NOMs) was also demonstrated.
Determination of an effect of 3-chlorophenol on hydroxyl radical generation during ozonation through kinetic study in the power law type
Authors: Han Y.-H. , Koshiishi I. , Utsumi H.
Published: May 2018

Ozone decomposition in aqueous solution proceeds through a radical type chain mechanism. These reactions involve the very reactive and catalytic intermediates hydroxyl (OH) radical, O2− radical, HO2 radical, OH−, H2O2, etc. OH radical is proposed as an important factor in the ozonation of water. In the previous study, generation of OH radical in the ozonation of water containing 3-chlorophenol was mathematically evaluated. In this study, we estimated the kinetic equation for the effect of 3-chlorophenol on OH radical generation during ozonation using the power law equation, in order to analyze it more correctly. The OH radical was trapped with a 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) as a stable adduct, DMPO-OH. The relationship between the ozone concentration, 3-chlorophenol content, and the initial velocity (ν0) of DMPO-OH generation was analyzed mathematically, and the following equation was obtained: ν0 (10−6 M/s)=(1.58×10−5)×[3-chlorophenol (10−6 M)]×[ozone (10−6 M)]2.40+(3.09×10−5)×[ozone (10−6 M)]1.72. The equation fitted very well with the experimental results, and square of the correlation coefficient was larger than 0.9.
Application of iron-coated sand on the treatment of toxic metals
Authors: Yang Jae-Kyu , Chang Yoon-Young , Lee Sung-Il , Choi Hyung-Jin , Lee Seung-Mok
Published: May 2018

Iron-coated sand (ICS) prepared by using FeCl3 and Joomoonjin sand widely used in Korea was used in this study. In batch adsorption kinetics, As(V) adsorption onto ICS was completed within 20 minutes, while adsorption of Pb(II), Cd(II), and Cu(II) onto ICS was slower than that of As(V) and strongly depended on initial pH. At pH 3.5, ICS showed a selective adsorption of Pb(II) compared to Cd( II) and Cu(II) . However, above pH 4.5, near complete removal of Pb(II), Cd(II), and Cu(II) was observed through adsorption or precipitation depending on pH. As(V) adsorption onto ICS occurred through an anionic-type and followed a Langmuir-type adsorption behaviour. In column experiments, pH was identified as an important parameter in the breakthrough of As(V). As(V) breakthrough at pH 4.5 was much slower than at pH 9 due to a strong chemical bonding between As(V) and ICS as similar with batch adsorption behaviour. With variation of ICS amounts, the optimum amount of ICS at pH 4.5 was identified as 5.0 grams in this research. At this condition, ICS could be used to treat 200 mg of As(V) with 1 kg of ICS until 50 ppb of As(V) appeared in the effluent. In this research, as a new treatment system, ICS can be potentially used to treat As(V) and cationic heavy metals.
A benchmarking study for reforming a Korean water department
Authors: Lee S. , Park H. , Choi D.
Published: May 2018

This study is aimed at developing internal reform plans for a water department of Seoul City by benchmarking it with selected best practices of the world. At first a performance indicator system was developed to logically evaluate concerns, problems, and issues of the Seoul water department. Since it is typical of Korean water services providers, the Seoul water department was selected while Tokyo's in Japan and Denver's in America were selected since they were considered as best practices of public waterworks much similar in governing structure to the one in Seoul. The results of benchmarking concluded that Seoul has traditionally been emphasizing more on “being a good public servant” providing drinking water services, and should be reformed in directions emphasizing ‘entrepreneurship’ to overcome its current limitations. Based on the results, a road map to reform the Seoul water department was established. Since it is typical in Korea, the reform plans and road map established were further recommended for reforming other drinking water services providers in Korea.
Service to the poor in megacities of developing countries: how to combine efficiency and equity?
Authors: Breuil Lise
Published: May 2018

Explosive urbanisation in developing countries during the last thirty years led to a crisis of water services in big cities, which cannot meet population increase and fail to supply water to up to 30% of the population. In this paper, we assume that the organisation of water services can be characterised by three key dimensions of governance: the mechanisms of coordination that regulate interdependence between stakeholders, the processes of adhesion of all stakeholders to the model, and the incentives provided in order to achieve objectives. We propose a three-dimensional analysis of the water reforms undertaken during the last 30 years and a new model based on public-private partnership, that could fit risky environment and reconcile efficiency with equity. The model is illustrated thanks to a Brazilian case study.
Inactivation of viruses, bacteria, spores and protozoa by ultraviolet irradiation in drinking water practice: a review
Authors: Hijnen W.A.M. , Medema G.J.
Published: May 2018

The inactivation rate constants (k-value) of pathogenic viruses, bacteria and protozoa and indicator or model microorganisms for monochromatic UV253.7 radiation have been calculated from literature studies describing experiments of seeded microorganisms in collimated beam apparatus with low-pressure lamps. Results show that data of most studies fitted well in the first-order Chick-Watson disinfection kinetics. Viruses require the highest UV fluence and the double-stranded DNA adenovirus is by far the most persistent species with an UV fluence requirement of 125 mJ/cm2 for 3 log inactivation. Translation of these k-values to full-scale UV systems requires accurate fluence assessment in these continuous flow systems with fluence distribution, variations in water quality (UV transmittance) and operational aspects like lamp age and fouling. Determination of the reduction equivalent fluence or REF with seeded model organisms is an accepted methodology to validate UV systems. Frequently used model organisms F-specific RNA phage MS2 and spores of Bacillus subtilis have low k-values. For validation of systems with low fluence requirement to inactivate UV sensitive organisms, alternative model organisms are suggested. Further research is needed to verify the potential of REF verification of full-scale systems by monitoring inactivation of indigenous spores (anaerobic or aerobic) with large volume sampling.
Economic modelling for groundwater resources management
Authors: Xepapadeas A.
Published: May 2018

Conceptual models related to the management of groundwater resources are presented. Socially optimal and privately optimal, or atomistic, management rules and outcomes are compared, and decentralized policy schemes, in the form of water taxes, that can be used to sustain socially optimal use of groundwater resources are explored.
Derivation of irrigation water demand functions through linear and non-linear optimisation models: application to an intensively irrigated area in northern Greece
Authors: Latinopoulos D.
Published: May 2018

The growing need for sustainable management of water resources has introduced the implementation of water pricing as an indirect method for efficient and sustainable water use. Agriculture is the main consumer of water worldwide but in many countries it is also a very fragile socioeconomic sector. Within this sense, the paper examines the effect of irrigation water pricing on water demand and on farmers' income. The derivation of a demand function through a linear programming model is the most common approach as it is relatively easy to be implemented and has limited data requirements. However, this method does not allow for a possible reduction of water consumption from the maximum level of water productivity in order to attain the maximum economic outcome. Thus, a non-linear model was formulated in order to estimate the best allocation of water and land resources for each crop. The results show significant differences between the two models (the linear and the non-linear), especially at high water prices.
Trans-national water supply benchmarking: the cross-border co-operation of the Bavarian EFFWB project and the Austrian OVGW project
Authors: Theuretzbacher-Fritz H. , Schielein J. , Kiesl H. , Kölbl J. , Neunteufel R. , Perfler R.
Published: May 2018

Based upon the IWA performance indicator system benchmarking projects for water supply enterprises have been carried out in Bavaria (Germany) and Austria. Due to the similar water supply structure of these neighbour countries, a cross-border co-operation was defined to develop a compatible system and to conduct trans-national comparisons. In this paper, the two projects and the cross-border co-operation are described. First comparison results are presented for key indicators showing a good overall performance in both projects, especially with reference to international levels.
Direct billing of multi-family customers for water use presents new opportunities and challenges to water providers in the United States
Authors: Bennett R.E.
Published: May 2018

As water and wastewater rates increase faster than the rate of inflation, more and more buildings in the multi-family housing sector are converting to systems where each multi-family dwelling unit pays for water and wastewater directly instead of including these charges as part of the rent. The National Multiple Family Submetering and Allocation Billing Program Study evaluated the merits of separate billing programs including the potential water savings, costs and benefits from various perspectives, and the accompanying administrative and regulatory issues. It was found that the practice of installing individual water meters (submetering) on multi-family apartment units and billing based on actual consumption results in water savings of 15%. Water billing practices based on allocation methods (commonly known as Ratio Utility Billing Systems or RUBS) did not effect any water savings. The study was motivated by the water industry's interest in capturing potential water savings by multi-family residents where there is currently no pricing signal to encourage efficient use.
The introduction of water banks in Spain: perspectives and possibilities
Authors: Milla J. L.
Published: May 2018

In 1999, the Spanish Government reformed the Water Act in order to introduce some measures theoretically proposed to favour the transmission of the concessions that dictate water use rights. One of these measures is termed ‘water use rights exchange centre’ which is mainly prompted by the Central Administration. Recently, the constitution of these exchange centres has been approved in the Guadiana River, Júcar River and Segura River Basins. The Spanish Government announced that it expects to lay the foundations for the creation of future ‘Public Water Banks’. This paper seeks to analyse the current situation and the limits imposed by legislation related to concessions that have already been granted, as well as the characteristics of the proposed exchange centres and the available alternatives for the regulation of the new water banks.
Defining the conservation potential for San Francisco's 28 wholesale customers
Authors: Levin E. , Carlin M. , Maddaus W.O. , Sandkulla N.
Published: May 2018

This paper documents the methodology and results of a comprehensive water demand and conservation study conducted in 2003 and 2004 under the direction of the San Francisco Public Utilities Commission (SFPUC) in conjunction with its 28 wholesale customers. These customers are represented by the Bay Area Water Supply and Conservation Agency (BAWSCA). The SFPUC supplies water to about 1.6 million people within the San Francisco Bay Area plus about 700,000 within the City of San Francisco itself.

A detailed benefit-cost analysis was conducted using the Demand Side Management Least-Cost Planning Decision Support System (DSS) model for 32 conservation measures using the individual customers' DSS model. Thirty-year water savings, benefit–cost ratios, and the cost of water saved were computed for each measure.

Based on compiling the results from the individual customer demand models, it was found that the current plumbing and appliance codes would reduce overall 2030 water demand by 7.8% and that packages of additional water conservation measures could reduce demands by an additional 2–6%, depending upon the level of conservation implemented. Overall, the study represents one of the largest water demand and conservation evaluation projects undertaken in the United States.