bluuebunny/crossref_metadata_2025 huggingface dataset:
Upgrading conventional treatment processes for water quality improvement - a pilot study
Authors: Chen J.-J. , Yeh H.-H. , Tseng I.-C. , Lin T.-F. , Lai W.-L.
Published: May 2018

Cheng Ching Lake Water Works (CCLWW), located in southern Taiwan, draws its raw water from a eutrophic lake, which is treated by conventional processes, including pre-chlorination, coagulation, sedimentation, filtration, and disinfection. As the taste- and odor-causing compounds from algae cannot be completely removed by conventional treatment processes, and the hardness is high, there are complaints about water quality. In searching for suitable processes to upgrade the existing facilities, a two-year pilot plant test was conducted. In total 13 processes were tested, which could be divided into three groups. The main feature of the first group was the modification of the existing conventional treatment processes, which included eliminating pre-chlorination and incorporating GAC. The second group incorporated pre- and post-ozonation, GAC bed, with or without pellet softening, into the conventional processes. The third group featured membrane processes, mainly nanofiltration (NF) and its various pretreatment processes, such as microfiltration (MF) or ultrafiltration (UF). The results show that although the first group has higher removal rates of dissolved organic and disinfection by-product precursors, as measured by NPDOC and THMFP, respectively, than those from the existing full-scale plants, the improvement in taste and odour was not adequate. For the second group, the dissolved organic parameters and biostability of the finished water were further improved, and half of the total hardness could be removed by pellet softening. However, earthy and fishy odours still could be detected occasionally by flavour profile analysis. Generally speaking, the third group with processes involving NF could produce the highest quality finished water: no matter organic, inorganic, organoleptic parameters, or biostability were concerned.
Modifications of unit processes for finished water quality improvement at the Kueui water treatment plant in Seoul
Authors: Yu M.J. , Cho H.M. , Koo J.Y. , Han I.S. , Gwon E.M. , Oh H.K.
Published: May 2018

Recently, Seoul city has tried to modify and upgrade the existing facilities and utilities and to improve the established water treatment plants, instead of application of a new treatment process. These efforts have finally lowered the turbidity of finished water below 0.1NTU. Small lab-scale and pilot-scale experiments have been conducted and they have provided optimum parameters for the design and operation of drinking water treatment plants. In addition, quantitative and/or trace analysis technologies developed for monitoring water quality of effluent from unit processes and automization of facilities, have contributed to the improvement of turbidity in drinking water. The Kueui water treatment plant, one of the drinking water treatment plants in Seoul, produces finished water with 0.08 NTU. It results from the operators' continuous endeavor to lower the turbidity in a scale of 0.01 NTU. The data for 12 months indicated that turbidity of settled water was less than 1.16 NTU and that of filtered water was less than 0.12 NTU for 95% of the period. Sedimentation basins and sand filters satisfy the recommended turbidity criteria, 2 NTU and 0.3 NTU, respectively. Also Kueui water treatment plant has focused on the control of organic matters to decrease in DBPs and on the removal of microorganisms.
Photocatalytic degradation of propanil and molinate over TiO2 suspensions
Authors: Albanis T.A. , Konstantinou I.K. , Sakkas V.A.
Published: May 2018

The light-induced degradation of propanil and molinate under simulated solar irradiation has been investigated in aqueous solutions containing TiO2 suspensions as photocatalysts. The study focuses on the identification of possible intermediate products and the determination of inorganic ions formed during the process, using several powerful analytical techniques such as gas chromatography mass-spectrometry (GC-MS) and ion chromatography (IC). The primary degradation of propanil and molinate has been a fast process with half-lives varying from 4.3 to 2.9 minutes respectively, and followed pseudo-first-order kinetics according to the Langmuir-Hinshelwood model. The stoichiometric transformation of organic chlorine into chloride ion and organic sulfur to sulfate ions was observed for propanil and molinate respectively, whereas oxidation of nitrogen to nitrate ions took place at delayed irradiation times for both herbicides. The mineralization of the organic carbon to CO2 after 240 min of irradiation was found to be ≥ 95% for both herbicides. Various organic intermediates detected during the treatment have been identified by GC/MS techniques. Based on this by-product identification, a possible multi-step degradation scheme was proposed for each herbicide including hydroxylation, dechlorination, dealkylation and oxidation steps that lead to the mineralization of the starting molecule.
Decision support system for optimisation of iron removal from groundwater
Authors: Sharma S.K. , Petrusevski B. , Jonoski A. , Ijpelaar G.F. , Schippers J.C.
Published: May 2018

Floc filtration and adsorptive filtration are the two main physicochemical mechanisms of iron removal in filters. Under the commonly applied treatment conditions in iron removal plants, the floc filtration is commonly believed to be the dominant mechanism and the adsorptive filtration complimentary. Iron removal filters with iron oxide coated sand are expected to perform better in terms of filtrate quality, filter run time and costs, by switching the mode of operation from predominantly floc filtration to predominantly adsorptive filtration. A decision support system (DSS) is being developed to assess the applicability and to quantify the possible benefits associated with adsorptive iron removal for a given groundwater and a specific plant. This paper introduces the different independent and interconnected modules of the DSS and elaborates on one particular sub-module for the analysis of the extent of floc filtration and adsorptive filtration iron removal in a groundwater treatment plant under given conditions. This computer model would be helpful in optimising the plant performance under the existing mode of operation, formulating strategies for switching from floc filtration to adsorptive filtration, and designing new iron removal plants. Sensitivity analysis showed that pH, iron oxidation rate constant and pre-oxidation time (a function of depth of supernatant and filtration rate) are the main parameters determining the extent of floc filtration and adsorptive iron removal under given conditions. Predominantly adsorptive iron removal in filters can be achieved by reducing the depth of supernatant, increasing the rate of filtration and/or controlling the oxygen concentration in the feed water.
“Jan-Lagrand” water treatment works: UF/RO from technological novelty to full size application
Authors: de Bruijn F. , Kamp C. , Eddy D. , Kools J.E.
Published: May 2018

In Heemskerk the world's largest dual membrane municipal water treatment works ( WTW) “Jan-Lagrand” (55 Ml/d or 2,250 m3/h or approximately 15 MGD) was commissioned at the end of 1999. At Heemskerk WTW, pretreated surface water is subsequently treated by ultrafiltration (UF) and reverse osmosis (RO). The RO permeate is directly blended into drinking water without chemical disinfection.

Before Heemskerk the dual membrane concept had not been considered on this scale, and during project preparation numerous developments and innovations needed to be flexibly accommodated into the ongoing design. Conceptual system development, pilot research and design and engineering were successfully conducted “in parallel”.

This paper deals with the innovations that were materialized in Heemskerk, e.g. UF-membrane pretreatment, on line membrane integrity testing (UF and RO) for disinfection approval, and a dual floor building concept for membrane installations. This paper explains how these innovations could be accommodated into an ongoing design, while innovative testing was still proceeding.
Fouling of microfiltration membranes by the fractional components of natural organic matter in surface water
Authors: Fan L. , Harris J. , Roddick F. , Booker N.
Published: May 2018

This paper examines the effect of the fractional components of natural organic matter (NOM) in surface water on the fouling of microfiltration membranes. The results are shown for the NOM derived from the Mt. Zero drinking water reservoir located in the state of Victoria, but they are representative of the other two water reservoirs investigated in the full study. The NOM was concentrated and isolated into four fractions according to hydrophobicity and charge using non-functionalised and anionic resins. Filtration experiments were conducted in a stirred cell using 0.22 μm hydrophobic and surface-modified hydrophilic polyvinylidene fluoride (PVDF) membranes to examine the fouling effects by the NOM fractions on membranes of different hydrophobicity. The fouling rate and extent of fouling were considerably less for the hydrophilic membrane compared to the hydrophobic membrane, which was due to the reduced organic interactions (i.e., hydrophobic adsorption, charge interaction) between the NOM and the hydrophilic membrane. However, for both the hydrophilic and hydrophobic membranes, the order of the fouling potential of the four fractions was the same, namely hydrophilic neutral > hydrophobic acids > transphilic acids > hydrophilic charged. The explanation for the high fouling potential of the hydrophilic neutral fraction was attributed to the calcium and carbohydrates (mainly polysaccharides) in the NOM, which were found to concentrate in the hydrophilic neutral fraction. Fourier transform infrared spectroscopy (FTIR) spectra for the fouled hydrophobic PVDF and polypropylene membranes revealed some visible changes in the regions of Ar-O-Ar, C-C, C-N stretching and C-H rocking vibrations, indicating polysaccharides and aromatics being the important foulants on the hydrophobic membranes. The mechanism by which the hydrophilic neutral fraction caused severe membrane fouling was a combination of adsorption of polysaccharides on the membrane structure due to hydrophobic bonding of the non-polar segments of the polysaccharides, and electrostatic attraction interactions between the polysaccharide-Ca2+ complexes and the negatively charged membrane.
Optimum location of an ultraviolet step in a surface water treatment plant
Authors: Lemoine C. , Gatel D. , Cavard J.
Published: May 2018

To meet the new DBP rules, ozone doses will have to be minimized to control bromate formation. In some surface water treatment plants, this situation may become of concern, since disinfection will have to be maintained at the current level. Alternative disinfection means such as UV have therefore to be evaluated, and this study was designed to evaluate the impact of MP-UV on water quality parameters such as atrazine, BDOC or nitrites, to determine whether such a treatment step should be inserted before or after the current GAC filtration unit. According to the results shown here, this question is not an issue under conditions needed for Cryptosporidium inactivation.
Application of physico-chemical parameters and particle-bound biomarkers to indicate microbial contamination of aquifers
Authors: Roser D. , Ashbolt N. , Storey M. , Leeming R. , Scott P. , Bennetts R. , Ryken-Rapp D. , Toze S.
Published: May 2018

Reliance on coliform monitoring of ground waters is slowly changing as is reflected in the proposed US EPA Ground Water Rule. In line with this we have investigated the use of an expanded range of faecal indicators and potential surrogate analytes within the Gwelup and Jandakot borefields in Perth, Western Australia. The aims of the study included comparing contamination in bores and surface waters in vulnerable locations, quantifying aquifer removal of microorganisms, trialing novel biochemical pollution indicators such as faecal sterols, assessing Escherichia coli as a measure of groundwater contamination and generating data for risk assessments. Sampling was undertaken of nine production bores, nine monitoring bores and four surface waters for 32 parameters comprising seven microbial indicators, 12 physico-chemical parameters and 13 biomarkers (including 8 faecal sterols and caffeine) at sampling stations potentially impacted by urban development. Concentrations of microbial indicators and biomarkers followed the pattern: basins >> monitoring bores >> production bores. Only one production bore sample contained bacterial indicators (0.1 enterococci.100 mL-1 on 1 occasion). Of the faecal biomarkers, coprostanol was generally at background levels. Cholesterol appeared to be a more sensitive measure of infiltration, but was also effectively removed. E. coli appeared to be a less sensitive indicator than enterococci. None of the physico-chemical parameters were useful surrogates. Overall apparent faecal microbial removal by aquifer filtration averaged >4-5 logs (not accounting for viruses). To maximise warning time and assay sensitivity it is suggested that enterococci be considered as the key bacterial indicator rather than E. coli and that different combinations of indicators and biomarkers be used to identify aquifer locations at risk, the presence of significant faecal material, and the likely presence of pathogens.
Application of a fractionation technique for better understanding of the removal of natural organic matter by alum coagulation
Authors: van Leeuwen J. , Chow C. , Fabris R. , Withers N. , Page D. , Drikas M.
Published: May 2018

To gain an improved understanding of the types of organic compounds that are recalcitrant to water treatment, natural organic matter (NOM) isolates from two drinking water sources (Mt. Zero and Moorabool reservoirs, Victoria, Australia) were separated into fractions of distinct chemical behaviour using resins. Four fractions were obtained from each water source and were organics absorbed to: (1) XAD-8 (very hydrophobic acids, VHA); (2) DAX-4 (slightly hydrophobic acids, SHA); (3) bound to an anion exchange resin (charged organics, CHAR); and (4) not absorbed or bound to resins (neutrals, NEUT). These fractions were then tested to determine the capacity of alum to remove them from water and to correlate this with the character of each isolate. The fractions were characterised by the application of high performance size exclusion chromatography (HPSEC), bacterial regrowth potential (BRP), trihalomethane formation potential (THMFP), pyrolysis gas-chromatography mass spectrometry (Py-GC-MS) and thermochemolysis. The highest removals of dissolved organic carbon (DOC) by alum treatment were in waters spiked with the CHAR fractions while the NEUT fractions were the most recalcitrant. The number average molecular weights (Mn) of DOC of the CHAR fractions before treatment were the highest, whilst those of the NEUT fractions were the lowest. After alum treatment, the Mn of the NEUT fractions were only slightly reduced. Results from Py-GC-MS and thermochemolysis indicate that the NEUT fractions had the highest relative proportion of saccharide derived organic material. Nonetheless, the BRP of waters spiked with the NEUT fractions differed markedly, indicating that organics recalcitrant to alum treatment can vary substantially in their chemical composition and capacity to support microbial growth.
Effect of natural organic compounds on the removal of organic carbon in coagulation and flocculation processes
Authors: Jegatheesan V. , Lamsal P.R. , Visvanathan C. , Ngo H.H. , Shu L.
Published: May 2018

Natural organic matter (NOM) in water contains organic compounds that are both hydrophobic and hydrophilic with a wide range of molecular weights. It is composed of non-homogeneous organic compounds such as humic substances, amino acids, sugars, aliphatic and aromatic acids, and other chemical synthetic organic matters. NOM in water is a major concern not only because of its contribution to the formation of disinfection by-products (DBPs) and taste and odor, but also its influence on the demand for coagulants and disinfectants, the removal efficiency of water treatment processes, etc. This research aims at identifying the influence of NOM in coagulation and flocculation processes in order to optimize the coagulation and flocculation conditions. In this study, pretreated pond water was used as the source water. It was observed from the experimental results that:The optimum pH for coagulation to remove NOM is around 7.The optimum alum dose at this pH can vary from 125-1,225 mgl-1 when the TOC is increased from 4 to 25 mgl-1.The presence of secondary compounds such as Ca2+, Mg2+ divalent cations had no significant effect on the removal of organic matter.The presence of clay increased the organic removal by 15%.The organic compound with higher molecular weight has higher removal affinity in coagulation process.Floc size and settling velocity of floc and sludge production all increased with the increase in NOM concentration. From the results of Capillary Suction Time (CST) tests, the floc formed with lower TOC readily released the water to make the dewatering process easier.The organic removal efficiency was significantly different for natural water containing non-homogeneous organic compounds compared to the synthetic water containing humic acid only (homogeneous organic matter).

For example, the NOM removal efficiency was 80% for the synthetic water containing humic acid with TOC of 7 mgl-1 at pH 7; but the NOM removal for the pretreated pond water was 60%.
Formation characterization and removal of disinfection by-products in water treatment processes
Authors: Chae S. , Wang C.
Published: May 2018

This study evaluates the formation and removal of DBPs along with precursors in a pilot-scale treatment plant employing conventional treatment processes (coagulation/ sedimentation/filtration), ozonation and granular activated carbon (GAC) treatment with three EBCT (10 min, 15 min, 20 min) and three types of GACs (coal-based F400, coal-based SLC, coconut-based SLC-2000). Pilot-scale study suggested that the GAC adsorber demanded more than EBCT 15 min for DBPs removal and exhibited excellent performance for HAA removal. During approximate a one-year pilot scale evaluation for ozone/GAC processes, as high efficiency of removal was continued, exchange cycle and regeneration life of GAC need to be decided through longer operation.
Comparison of disinfection byproduct (DBP) formation from different UV technologies at bench scale
Authors: Liu W. , Andrews S.A. , Bolton J.R. , Linden K.G. , Sharpless C. , Stefan M.
Published: May 2018

The impact of UV irradiation on disinfection byproduct (DBP) formation was investigated for low pressure, medium pressure and pulsed UV technologies using a broad range of UV doses. Four classes of DBPs (THMs, HAAs, aldehydes and carboxylic acids) were examined. This enabled the determination of effects resulting from the direct action of UV irradiation on natural organic matter (aldehydes, carboxylic acids) as well as effects on the ultimate formation of chlorinated DBPs (THMs and HAAs) from secondary chlorination. For doses of less than 1,000 mJ/cm2, UV irradiation did not affect THM and HAA formation in subsequent chlorination processes, however higher UV doses resulted in lower ultimate concentrations of THMs and HAAs. UV irradiation also resulted in the formation of aldehydes and carboxylic acids at UV doses above 500 mJ/cm2, compounds that are known to adversely effect drinking water biostability.
An innovative approach to small town water quality improvements
Authors: McLean R. , McManamon P.
Published: May 2018

Innovative solutions are required to meet the conflicting criteria of service level, community need, community desire, cost and risk to the supply authority in the delivery of water quality improvements to small regional communities. Grampians Region Water Authority services 74 towns in North-Western Victoria, an area of generally low rainfall, sparse settlement and few natural waterways. Town populations range from 10 to 13,000, with 56 towns having less than 500 people. A Water Quality Improvement Plan was recently developed by Grampians Water to address these natural difficulties. The plan examined a broad range of alternatives beyond the single-pipe reticulated supply system, including dual-pipe reticulation, rainwater sources and household water treatment systems for achieving target quality levels. The key findings were:• regional treatment plants are not economical if towns are more than 25 km apart• salinity is a major influence on strategy• for low salinity supplies, conventional treatment is most economical• for marginal salinity supplies, a two stage process involving conventional treatment and desalination is appropriate• desalination provides a total solution for high salinity groundwater supplies• drinking quality can only be economically achieved in very small towns by using household treatment of rainwater in a dual supply system. The resultant strategies and implementation issues outlined reveal some significant variations to the conventional approach.
What are we saving anyway? The results of three water demand management programs in NSW, Australia
Authors: Sarac K. , Day D. , White S.
Published: May 2018

The use of demand management programs to achieve permanent and reliable decreases in water consumption through retrofits of water using equipment is relatively new in Australia, and has been carried out on the basis of models which predict savings, and on results of demand management programs undertaken overseas. The availability of information on actual savings achieved by demand management programs in Australia is extremely limited. This paper outlines the results of the evaluation of three retrofit programs undertaken in NSW, two of which involved a visit by a plumber to households to carry out a retrofit of indoor water using equipment at a subsidised price; the other taking a “hands-off” approach and relying on a discount incentive mechanism to increase the market share of water efficient showerheads.
Management of large water resource systems
Authors: Mckenzie R.S. , van Rooyen P.G.
Published: May 2018

South Africa has one of the most complicated and integrated water resource systems in the world involving numerous interlinked river systems and major interbasin transfer schemes. The management of the various schemes has become a key issue over the past 15 years resulting in the development of sophisticated systems models which are now used to analyse and operate all of the country's major schemes. The models have been developed through a partnership between the Department of Water Affairs and Forestry in association with several of the country's consultants specialising in this area of expertise. The models have now reached a stage where they are considered to be both practical and sufficiently robust to use in other parts of the world.

Australia and South Africa are quite similar in many respects with regards to the water resources and climate. Both countries share the same problem of large arid or semi-arid areas together with areas where the local water resources are insufficient to meet the existing or predicted future demands. Environmental considerations are also of major importance in both countries which in turn necessitates the effective use of the available resources before any new resources can be developed.

In order to use the available water effectively much effort has been placed on various aspects of Water Demand Management in order to reduce leakage and excessive consumer use. It is also necessary, however, to ensure that the raw water resources are managed in an efficient and practical manner - something that is often easier said than done.

This paper provides general details of the system analysis techniques that have been pioneered in South Africa and discusses the most recent developments that can be used to assist water resource managers in the analysis and planning of their water resource systems.
Expert system for municipal wastewater management with emphasis in reuse
Authors: Economopoulou M.A. , Economopoulos A.P.
Published: May 2018

This paper presents a methodology that uses a knowledge base and inference procedures for developing rational wastewater management schemes for small to medium size communities with emphasis in the protection of human health, the reuse of treated wastewater, and the pollution minimization of water receivers. The system provides an optimal year-round treatment/reuse/disposal plan, which maximizes the wastewater reuse for irrigation, meets the applicable minimum municipal wastewater treatment requirements and observes the water quality standards of receivers with the minimum treatment costs. The solution is dynamic in the sense that varying monthly design values can be assigned to the input variables used in the computation of irrigation requirements, assimilative capacity of receivers and performance of natural systems. The above procedure shows that the use of multiple receivers over the year is often highly advantageous; combining for example the increased treatment efficiency and reuse potential for irrigation during summer with the increased assimilative capacity of a river during winter. The expert system incorporates a number of design and ambient quality models, for which graphical solutions have been developed, so as to enable manual application if desired. The entire procedure is implemented in an integrated computer program that facilitates and refines problem solution. The expert system provides interactive guidance for collecting the necessary field information. Finally, the results of a case study for the management of wastewaters from the six communities of the Municipality of Keramoti are presented.
The role of information on farmers' willingness to use recycled water for irrigation
Authors: Tsagarakis K.P. , Georgantzís N.
Published: May 2018

In this paper are identified several factors which affect a potential user's willingness to use recycled water for agricultural irrigation. This study is based on the results of a survey carried out among farmers in the island of Crete, Greece. It was found that a higher level of income and education are positively correlated with a respondent's willingness to use recycled water. Income and education are also positively correlated with a potential user's sensitivity to information on the advantages of using non-conventional water resources. Overall, extra information on the advantages of recycled water has a statistically significant impact on reported degrees of willingness to use recycled water.
Ultrafiltration as tertiary treatment for industrial reuse
Authors: Lubello C. , Gori R. , de Bernardinis A.M. , Simonelli G.
Published: May 2018

In this paper we present the results obtained from tests conducted on ultrafiltration treatment of a secondary effluent designated for possible industrial reuse. Tests were carried out at Empoli Wastewater Treatment Plant (WWTP) (Florence, Italy) with the use of a hollow fiber pilot plant (mod. ZW-10, Zenon Environmental). Testing lasted for about 4 months, during which the pilot plant was fed by effluent from the wastewater treatment plant. Results show that the permeate was of high quality. The membranes were very efficient in reducing turbidity (94.5%) and TSS (98.7%). The reduction of COD (around 35%) was also good. The permeate also showed low SDI values (usually < 3%). With respect to microbiological parameters, treatment was shown to be above all efficient in the removal of Escherichia coli. The permeate already respects required quality standards set forth by a new technical law decree on water reuse, soon to be approved within Italian Legislation. Based on these test results, a preliminary design of a wastewater treatment plant with the complex of structures necessary to the distribution of the treated wastewater in the industrial area located closed to the plant, has been created. Under this design, treated water could be produced at a cost of 0.38 Euro/m3, which includes investment, financial charges and maintenance costs.
Modelling of bacterial removal in wastewater storage reservoir for irrigation purposes: a case study in Sicily, Italy
Authors: Barbagallo S. , Brissaud F. , Cirelli G.L. , Consoli S. , Xu P.
Published: May 2018

In arid and semiarid regions the reclamation and reuse of municipal wastewater can play a strategic role in alleviating water resources shortages. Public awareness is growing about the need to recycle and reuse water for increasing supply availability. Many wastewater reuse projects have been put in operation in European and Mediterranean countries adopting extensive treatment systems such as aquifer recharge, lagooning, constructed wetlands, and storage reservoirs, mainly for landscape and agricultural irrigation. In agricultural reuse systems, there is an increasing interest in extensive technologies because of their high reliability, and easy and low cost operation and maintenance. Wastewater storage reservoirs have become the option selected in many countries because of the advantages they present in comparison with other treatment alternatives, namely the coupling of two purposes, stabilization and seasonal regulation. This paper describes an example of a wastewater storage system, built in Caltagirone (Sicily, Italy). The storage results in a tertiary treatment of a continuous inlet flow of activated sludge effluents. The prediction of the microbiological water quality has been evaluated by means of a non-steady-state first-order kinetic model. Single and multiple regressions were applied to determine the main variables that most significantly affected die-off coefficients. The proposed model has been calibrated using the results of a field monitoring carried out during a period from March to October 2000.
Water reuse in Israel - the Dan Region Project: evaluation of water quality and reliability of plant's operation
Authors: Icekson-Tal N. , Avraham O. , Sack J. , Cikurel H.
Published: May 2018

Israel is a semi-arid country with insufficient natural water resources. Wastewater effluent reuse and desalination have become the main source of water to compensate for the future water shortage. Today, between 65 and 70% of wastewater of urban and industrial origin is reused in agriculture after treatment in biological treatment plants around the country. The Dan Region Reclamation Project (Shafdan) is the largest wastewater treatment and reclamation project in Israel. 130 Mm3/yr of reclaimed water is used for unrestricted irrigation after soil aquifer treatment (SAT). Extensive water quality monitoring is performed to keep an efficient and safe wastewater reuse system. After 25 years of operation, the Shafdan deals with the following operational issues on an ongoing basis: Biofouling of the effluent pipelines from the wastewater treatment plant to the SAT, and a lack of capacity in the SAT system. Biofilm growth in the pipelines is controlled by intermittently applying chlorine based compounds at a 10 mg/L dosage for a few hours.
Modelling the formation of THM (trihalomethanes) during chlorination of treated municipal wastewater
Authors: Koukouraki E. , Diamadopoulos E.
Published: May 2018

Trihalomethanes (THM) concentrations were determined during chlorination of nitrified and partially nitrified secondary effluents, as well as tertiary effluent. Coagulation tests, with alum doses varying from 0.1 mM to 2.5 mM, were applied prior to chlorination to the nitrified effluent in order to remove organic carbon and thereby control the formation of THM. The results indicated that the operational variables of contact time, ammonia nitrogen concentration, pH and chlorine dose had significant effects on THM formation. In tertiary effluents, as the coagulant dose increased, THM formation decreased with a more pronounced reduction for doses higher than 1.5 mM. Modelling of the THM formation was made by means of empirical exponential models. For the chlorination of the nitrified secondary effluent, contact time, chlorine dose, pH and temperature were the model's independent variables, while for the partially nitrified secondary effluent the equivalent independent variables were the contact time, the chlorine dose and the ammonia nitrogen concentration. Modelling of THM formation during chlorination of tertiary effluent was based on either the DOC concentration or the ultraviolet absorbance, as well as on a combination of both. The three exponential models fit reasonably well the experimental data for all the coagulant doses, except for the 2 and 2.5 mM dose, where the reduction in organic matter was not as high as the equivalent reduction in THM formation. The use of the ultraviolet absorbance alone as an independent variable in the model provided a slightly better simulation of the measured THM concentrations.
Practical condition assessment options for critical trunk watermains
Authors: Nicholas D. , Heathcote M. , Moore G.
Published: May 2018

A review, originally carried out for Sydney Water Corporation, of a complete range of direct and indirect methodologies used to assess the condition of buried cast iron and steel water pipelines is presented. These techniques include pipe sampling, pit depth measurement, soil testing using various parameters, as well as other non-destructive testing (NDT) based on various electromagnetic principles. Both the literature and comprehensive field trials have shown that soil testing using linear polarisation resistance (LPR) methodologies as an input to statistical analysis packages is a cost-effective technique. Direct evaluation using remote field eddy current intelligent pigs can also be very useful for the direct examination of critical watermains but is limited to smaller sizes of DN 150-DN 375.
Integrated water asset management system (IWAMS)
Authors: Johnson E.
Published: May 2018

As data proceeds through different levels of an organisation from its capture to its processing and refinement, it is reported as information relevant to a particular application. Data can be adversely influenced during this conversion process which can result in sub-optimal decisions being made. The collection and handling of information for a water authority must therefore be organised. Asset management systems generally consist of three major constituents: inventory, programmed action, and optimisation. The institutional capacity needs of water authorities in developing countries require greater emphasis on the first of these two constituents. A pragmatic and simple-to-use Integrated Water Asset Management System (IWAMS) has been developed comprising water meter, leakage control and incident management modules. A water audit and water balance module facilitates the determination of the levels of unaccounted for water, as well as the unit cost of leakage. Water mains rehabilitation priorities can be established through the representation of various data collected in the form of a common severity rating that aids decision making.
Management strategies for optimum meter selection and replacement
Authors: Arregui F. , Cabrera E. , Cobacho R. , Palau V.
Published: May 2018

There are two main decisions faced by utility managers regarding meters in an undertaking: which meter to instal and when to replace it. Traditionally the criteria used to make these decisions have been arbitrary and often imposed by third parties regardless of the situation of the individual undertakings. This paper presents “Comparative billing analysis”, a methodology to analyse meter performance within the undertaking, as a means to support decision making in water meter management.

The main difference between the comparative billing analysis and previous methodologies resides in the use of the commercial billing database that most undertakings have these days. By analysing existing data with a systematic approach, it is possible to determine which kind of domestic meter is most appropriate for the utility. This method turns out to be as reliable as previous ones, but much more efficient in the use of economic and human resources.
Pipe breaks and the role of leaks from an economic perspective
Authors: Colombo A. , Karney B.W.
Published: May 2018

A map depicting the major elements, interactions, and life cycle analysis issues of a typical water distribution system is presented as a network labyrinth. From this, focus is placed on the influence of leaks on energy and water consumption as well as the dissipation of hydraulic transients. Straightforward analytical expressions are derived in order to relate the energy efficiency of a leaky pipe to leak location and orifice properties. The ability of leaks to relieve pressure during hydraulic transients is briefly discussed with several challenges and issues surrounding the quantification of this attenuation effect being put forward. Considered from the broader perspective of the network labyrinth, a better understanding of leak related effects has implications for pipe rehabilitation models, system economics and environmental sustainability.
Effects of chlorine level on the growth of biofilm in drinking water pipes
Authors: Chu C. , Lu C. , Lee C.M. , Tasi C.
Published: May 2018

Three analogous laboratory-scale water pipe systems were constructed to study the effects of three chlorine levels of finished water on the growth of biofilm. The experimental results indicated that the heterotrophic plate counts (HPCs) of biofilm for chlorine-free water were approximately 2 and 3 orders of magnitude higher than those for low-chlorine water (0.3-0.5 mg/l Cl2) and high-chlorine water (1.2-1.5 mg/l Cl2), respectively. The difference in HPCs between low-chlorine water and high-chlorine water was below 1 order. Average biofilm formation rates are 325 ATP pg/cm2 per day for chlorine-free water, 159 ATP pg/cm2 per day for low-chlorine water and 118 ATP pg/cm2 per day for high-chlorine water. Scanning electron microscope (SEM) observation showed that bacterial species separated from the biofilm were more complex than from the finished water. The Gram-negative bacteria were dominant.
Nanofiltration: improvements of water quality in a large distribution system
Authors: Peltier S. , Cotte M. , Gatel D. , Herremans L. , Cavard J.
Published: May 2018

A nanofiltration (NF) treatment was introduced during the autumn of 1999 in the Méry-sur-Oise treatment plant which feeds the northern Parisian suburbs distribution system. A study was conducted over 4 years to compare the water quality before and after nanofiltration. The results confirmed that NF treatment produced a low DOC concentration in water (average 0.7 mg C/L). This reduction of DOC concentration levels enabled an improved stability of chlorine residual that has been reduced to 0.2 mg/L at the outlet of the plant. The formation of trihalomethanes was thus reduced by 50% in the network. Moreover, the reduction of BDOC enabled an improved biological stability in the water and enhanced the microbiological water quality during distribution. In addition, the NF treatment enhanced the physico-chemical water quality.
Investigation into the implementation of chloramination at Sedibeng Water
Authors: Basson N. , Traut D. , Titus G. , vd Walt C. , Haarhoff J.
Published: May 2018

The Balkfontein and Virginia plants of Sedibeng Water, situated in the Free State Province of South Africa, treat water for potable purposes. Chlorine is used as disinfectant at both plants. Low levels of free chlorine measured in the water supplied from some reservoirs, logistics and costs, related to the application of chlorination at various points in the distribution system, were the main thrusts for an investigation into the use of chloramination as an alternative means of disinfection.

The so-called contact time (CT)-approach from the United States Environmental Protection Agency was applied for the evaluation of disinfection efficiency. The distribution system was modelled by using a hydraulic computer system. Decay rates for both chlorine and monochloramine - a vital parameter for eventual determination of the amount of chlorine and ammonia to be dosed - were determined. The levels of disinfectant in the water at a specific location could be predicted by using the decay values.

The main findings of this investigation are that chloramination is an attractive and cost-effective alternative for conventional chlorination for providing quality assurance to all. It is estimated that the capital layout will be recovered within one year of operation of the ammoniation system.
Canal de Isabel II solution for remote control over small and scattered facilities
Authors: Zubizarreta J.I.
Published: May 2018

A description is given of the solution used by the Canal de Isabel II (CYII) in response to the need to monitor 500 small facilities scattered throughout a region covering a surface area of 8,000 km2.

The system design, and the hardware and software, have been developed entirely by the CYII using easy-maintenance criteria. As most of the facilities lack an electricity supply, alternative methods are used. Energy consumption is greatly reduced by intermittent operation. Communication is by radio, making use of the company’s own networks.

The theoretical bases of the intermittent operation, the overall characteristics and the experience obtained are all explained through an approach that focuses upon the part of the system that is installed in situ.
Application of quality management systems for drinking water quality
Authors: Nadebaum P. , Chapman M. , Ortisi S. , Baker A.
Published: May 2018

Over the past few years the water authorities in Australia have been applying the principles of quality management and risk management in their provision of drinking water of a safe and acceptable quality. These principles have been taken up by the regulatory authorities, and the Australian water industry is ensuring that drinking water guidelines, customer contracts, licences and auditing (both statutory and quality systems auditing), and appropriate quality management systems, are in place for drinking water quality management. A particular focus of this work has been the application of AS/NZS 4360 (Risk Management) and the principles of Hazard Analysis and Critical Control Points developed for the food industry. This paper discusses the important considerations in applying quality management systems to drinking water quality management within water authorities, and the key issues of how best to integrate these risk management systems with the business management systems of the water authority. A generally applicable model for drinking water quality management systems based on ISO 9002 and HACCP is described. The paper also discusses the process of how management systems already in place within a water authority can be assessed and improvements identified. The objective is that the management systems will be consistent with the authority’s existing business management systems, ISO 9001, the principles of HACCP and AS4360, and the expected requirements of the revised Australian Drinking Water Guidelines.
Hydrology, hydraulics and economics: a case study of abstracting water from an estuary
Authors: Luketina D. , Hranisavljevic D. , Clark S. , Fan F. , Sahu M.
Published: May 2018

Designing a least-cost scheme to drinking water from an estuary is a complex task when the water is to be supplied to a town or city close to the mouth of the estuary since the estuarine water is relatively saline in this region. The raw water intake must be sited to minimise the cost of capital works, which may include increased storage, while maintaining the salinity of water supplied to customers within acceptable limits. This is not a trivial exercise as flow in estuaries, i.e. where the river and ocean meet, is complicated by tides, winds, upstream river inflows, erosion, and the rotation of the earth resulting in a relatively complex system in which salinity can vary dramatically in time and space. In turn, the level of risk (of exceeding acceptable salinity in water supplied to the customer) varies depending upon the estuarine behaviour and factors, such as abstraction location, available water storage, and abstraction practice. Here we show, via a case study, how hydrology, hydraulics and economics must be integrated in order to find a least-cost solution that meets the needs of customers.
Using staff surveys to identify business improvement opportunities
Authors: Jones K.
Published: May 2018

Staff survey techniques can quantify staff opinions and help reveal business improvement opportunities. Two specific formats have been devised for water industry agencies to characterise the degree of ”business approach” within an organisation and to assess the readiness of staff to respond to change
Marketing a technical business
Authors: Karbowiak P.
Published: May 2018

Until recently most water utilities have operated as a public service. The market is still predominantly a natural monopoly. The significant infrastructure requirements militate against service duplication and competition. Generally customers do not have the option of changing service providers. With the arrival of competition policy, water utilities have initiated some customer service programmes. However, the driver for this change has been the reporting requirements of the regulator rather than customer focused imperatives.

However, there are benefits for water service companies to conduct professional market research focused on customer satisfaction. This paper reviews the concepts of market customer satisfaction analysis. It discusses the shortfalls of generic methodologies which focus on the performance of the service provider rather than the needs and expectations of the customer. The application of Benchmarking or Best Practice, is also reviewed within this context.

A conclusion of this paper is that the application of focused, professional customer satisfaction analysis is an effective quality management tool and leads to a better understanding of water services customers’ needs and expectations. The outcome is more effective application of customer service resources, enhanced community perceptions and the achievement of higher levels of customer satisfaction.
Water management of big events
Authors: Meggeneder M. , Rosenwinkel K.-H.
Published: May 2018

Highly frequented big events play an increasing role in modern, leisure-oriented society. If you wish to host world exhibitions, trade fairs, sports events or other fairs you not only have to aim for sufficient visitors to match your economic expectations. As well as extensive use of service industries, the provision of a sufficient and reliable water supply, a wastewater disposal and sanitary equipment is crucial. In this article advice to prepare for big events and performance indicators for the consumption of venues will be given. Furthermore predictions on water consumption, ways to reduce the consumption and contractual aspects will be touched on.