bluuebunny/crossref_metadata_2025 huggingface dataset:
Management strategy of emergencies and events in the monitoring of water distribution in Paris
Authors: Montiel F. , Coutelan J.
Published: May 2018

For water distributors, management of emergencies and the follow-up of events in real time represent an essential aspect of their work. Proper management of this information makes for optimization of its use and enables one to avoid a large number of problems regarding water supply thanks to improved reactivity and more precisely-focused action.

Since 1992, Sagep (Société Anonyme de Gestion de l’Eau de Paris) to whom the City of Paris has entrusted responsibility for its water supply, has equipped itself with a computerized real-time monitoring system. Initially, this system processed 5,000 pieces of real-time information, which permitted monitoring of the 1,600 km of drinking water pipes and made possible distribution of the 650,000 m3 of drinking water consumed daily by Parisians.

In 1996, given the enormous progress achieved with regard to information systems and measuring devices installed in the pipe networks, the Scada at Sagep was modernized. This made possible the integration of the fresh information necessitated by developments in the supply system of the City of Paris, plant renovation, new sensors, the traceability of events and water quality follow-up.

These developments led to the integration and management of 17,500 pieces of real-time information, over three-quarters of which are made up of emergencies or events. It seems clear that it is impossible to manage such a mass of real-time information in the absence of a rigorous processing strategy. To exploit this set of data in optimal fashion, Sagep has developed a system of management of emergencies based on three thrusts: identification, qualification and processing.
Issues of operational integrity in membrane drinking water plants
Authors: Johnson W. , MacCormick T.
Published: May 2018

In the last five years over 100 microfiltration (MF) and ultrafiltration (UF) drinking water plants have been installed in Europe with a combined output of some 1,500 ML/day. The impetus behind this growth is concern over drinking water quality, regulatory pressure, the rapidly declining costs of membrane systems, and consumer pressures for non-chemical treatment. Although the principal justification for membrane plants is their capacity to remove human pathogens more effectively than conventional treatment, the ability of large plants to retain an integral barrier is not well understood. Currently available technology can monitor a full-scale membrane plant for integrity against passage of bacteria and parasites but not viruses. In essence the plant operator has to rely on the membrane manufacturer – on an assumption that if the membrane is not compromised at a level of 1 to 2 μm (the current practical level of measurement) it is also not compromised for virus removal. This paper quantifies the loss of integrity that can occur from membrane fiber failure. It explains the mathematical models used to describe bypass flow through compromised fibers and correlates the results with laboratory tests. Both are compared with artificially compromised fibers in a large full-scale operating plant. Under the worst case scenario where a fiber breaks close to the pot (collection end of the filtration module or element) the relative loss of integrity between alternative process designs from a single broken fiber can differ by as much as 2 log reduction values. The analysis demonstrates the need for monitoring methodology that that can track incremental changes in integrity to allow scheduled rather than emergency maintenance. It highlights the need for regulatory authorities to approve membrane systems based on actual operating performance in preference to laboratory data.
Scale inhibitor and recovery optimization for a brackish water supply: pilot test results and full-scale experiences
Authors: Duranceau S. , Lovins W.A. , Foster J.V. , Taylor D. , Morton J. , Morton C.
Published: May 2018

Pilot testing was conducted at a brackish water reverse osmosis water treatment plant to identify operational constraints associated with effective scaling control. The test program involved testing select inhibitors/dispersants, feed water pH, and operating recovery as part of a full-scale retrofit from a hollow fiber to spiral-wound reverse osmosis membrane facility. The test results indicated the facility could be operated at elevated recovery, but was sensitive to conditioning with sulfuric acid. Use of sulfuric acid addition to control calcium carbonate scaling was determined to increase calcium sulfate scaling. Membrane autopsy data confirmed calcium sulfate scaling onto the membrane surface with minimal biological and organic content. It was determined that recovery could be increased from 65 to 75 percent by discontinuing sulfuric acid addition and feeding only scale inhibitor. Scale inhibitors with dispersant properties were recommended for full-scale implementation.
Organic matter fouling of ultrafiltration membranes
Authors: Makdissy G. , Croué J.-P. , Buisson H. , Amy G. , Legube B.
Published: May 2018

The overall objective of our work is to identify the organic fraction responsible for fouling of lowpressure (microfiltration and ultrafiltration) membranes, and to understand fouling mechanisms. Several natural organic matter (NOM) fractions isolated from Ribou Reservoir have been ultrafiltered with two different 100 KD membranes (regenerated cellulose and polyethersulfone) using a non-stirred cell unit. Results have shown that the organic colloidal fraction (bacterial peptidoglycan residue) shows the most significant fouling. The dissolved fraction (<0.45 μm) of NOM, which contains solutes larger and smaller than the pore size of 100 KD membranes, contributes to fouling through pore blockage and/or adsorption mechanisms. Atomic force microscopy (AFM) examination reveals morphological changes during membrane fouling. The polyethersulfone and regenerated cellulose membranes are relatively smooth. However, based on AFM, some of the fouled membrane surfaces appear rougher than the corresponding clean membrane surface. These results demonstrate the role of surface coverage in ultrafiltration membranes. It appears that membrane roughness is a key physical parameter in membrane fouling. More analysis is being undertaken with scanning electron microscopy images to determine pore size distribution for the clean and the fouled membranes, providing more information in terms of fouling mechanisms.
Integral diagnosis of fouling problems by analysing biomass and inorganic compounds in membrane elements used in water treatment
Authors: Vrouwenvelder J.S. , Van der Kooij D.
Published: May 2018

Operational problems in membrane installations used in water treatment can be caused by a variety of fouling types. Therefore, a systematic approach based on the application of an autopsy of membrane elements followed by analysis has been developed, which enables an integral diagnosis of the type and extent of fouling. Analysis includes both biological parameters for biomass quantification (ATP) and biomass characterisation and chemical parameters for determining the presence of inorganic compounds (ICP-MS). Advantages of this approach include: first, complete and conclusive information about the nature and extent of fouling of the membrane filtration plant; and secondly, rapid diagnosis (within 8 hours) of biofouling. In addition to membrane element analysis, also a suite of monitoring tools (AOC test, biofilm monitor, oxygen consumption monitor and scaleguard) is available for elucidation and control of the processes responsible for the fouling problems. These tools can also be used to test chemicals for their effect on (bio)fouling. Research is continuing to substantiate relationships between test parameters and the extent of operational problems.
Fouling of low-pressure (MF and UF) membranes by wastewater effluent organic matter (EfOM): characterization of EfOM foulants in relation to membrane properties
Authors: Laabs C. , Amy G. , Jekel M. , Buisson H.
Published: May 2018

Low-pressure (micro- and ultrafiltration) membranes are increasingly being used in water reclamation processes treating secondary or tertiary effluent from wastewater treatment plants. The main challenge remains the fouling of membrane surface/pores by organic matter which prevents efficient operation. The extent of this fouling strongly depends on feed water quality as well as membrane properties. The aim of this study is to characterize wastewater effluent organic matter (EfOM) and to describe its fouling behavior in relation to various membrane properties (pore size, charge, material, hydrophobicity) through evaluation with stirred cell experiments, elemental analysis, 13C-NMR spectroscopy, and atomic force spectroscopy. Four membranes are tested - one ultrafiltration (UF) membrane and three microfiltration (MF) membranes - with bulk EfOM, derived from the Boulder, Colorado, USA, wastewater treatment plant, as well as with EfOM isolates. The hydrophobic microfiltration membrane is most seriously fouled by bulk Boulder EfOM, while the two hydrophilic membranes (MF, UF) made of cellulose acetate are the least fouled. Differences between the flux decline curves of various membranes are less distinct with isolates than with bulk EfOM. The transphilic isolate (TPIA-Bld) exhibited a higher fouling potential than the hydrophobic isolate (HPOA-Bld). This behaviour is due to the different chemical characteristics of the isolates, namely the higher percentage of hetero-atoms (oxygen and nitrogen) of the transphilic isolate compared to the hydrophobic isolate. Finally, atomic force microscope (AFM) images present clear evidence of fouling. AFM is clearly able to detect the fouling layer, although it has not been possible to distinguish between pore blockage and surface fouling thus far.
Recolamation of contaminated ground waters by a multiple membrane process
Authors: Macintosh P.D. , Fane A.G. , Papazoglou D.
Published: May 2018

This paper describes the application of a multiple step membrane train for the processing of ground and surface waters contaminated with ammonium sulfate. The key to the process is the unique ability of nanofiltration to separate mono and divalent ions such that the concentrated stream can be forwarded to an evaporator. The paper outlines the problems to be solved, the initial separation concept, the plant design, unique design features and the experience gained over a decade of operation. The process utilises microfiltration, nanofiltration and reverse osmosis.
Use of graft-modified membranes for water treatment
Authors: Meier-Haack J. , Carroll T.
Published: May 2018

Membranes with designed surface and filtration properties were prepared by grafting and adsorption of polyelectrolyte multilayer systems on membrane surfaces using the layer-by-layer electrostatic self-assembly technique. Microfiltration membranes with a first polyelectrolyte layer grafted onto the surface showed excellent stability during the filtration process. Although a two-fold higher permeate flux was observed for a three-layer polyelectrolyte complex membrane compared to a just grafted one, the protein retention did not change remarkably. Additionally, a reduced protein adsorption was detected by in-situ ATRFTIR spectroscopy for the case of repulsive electrostatic forces between the substrate and the protein under applied test conditions.
Coagulation/submerged hollow-fibre ultrafiltration for natural organic matter removal
Authors: Machenbach I. , Leiknes T. , Ødegaard H.
Published: May 2018

Experiments were carried out to investigate the removal of humic substances from highly coloured raw water (50 mg Pt/L) by coagulation and outside-in hollow-fibre membrane filtration. Chitosan, a cationic biopolymer produced from crustacean shells, and polyaluminium chloride (PACl) were used as coagulants. The rate of permeability decline was determined for different backwash frequencies and different fluxes at a 95% water recovery of the membrane. Coagulation with PACl gave a good and consistent permeate quality with removals of 95.6%, 84.9%, and 66.1% for true colour, UV absorbers, and dissolved organic carbon, respectively. Longer filtration intervals with less frequent backwashing as well as lower specific aluminium dosages increased the rate of permeability decline. The particle size distribution in the retentate tank was not affected by the frequency of backwashing. Chitosan was less effective in coagulating humic substances and the removal efficiencies were notably lower. Preliminary results suggest that the permeability declines somewhat faster for chitosan compared to PACl-coagulated water.
Performance of membrane bioreactor combined with pre-coagulation/sedimentation
Authors: Itonaga T. , Watanabe Y.
Published: May 2018

This paper deals with the performance of a hybrid membrane bioreactor (MBR) combined with pre-coagulation/sedimentation. Primary clarifier effluent in a municipal wastewater treatment plant was fed into the hybrid MBR to investigate its performance during long-term operation. Pre-coagulation/sedimentation process efficiently removed the suspended solids including organic matter and phosphorus. Comparison of the hybrid MBR and conventional MBR was made in terms of the permeate quality and membrane fouling. As the organic loading to the MBR was significantly reduced by the pre-coagulation/sedimentation, production and accumulation of extracellular polymeric substances (EPS) may be limited. Therefore, the mixed liquor viscosity in the hybrid MBR was much lower than that in the conventional MBR. These effect caused by pre-coagulation/sedimentation brought a remarkable improvement in both permeate quality and membrane permeability.
The course of giardiasis in Mongolian gerbils and SCID mice infected with new strains of Giardia lamblia
Authors: Sotiriadou I. , Karanis P.
Published: May 2018

The infectivity of Giardia isolates in Mongolian gerbils and in SCID mice inoculated with a newly established G. intestinalis strains of human origin (ISO/90/1, ISO/90/2) and a reference strain ATCC 30888 has been investigated. Inoculation of Mongolian gerbils with trophozoites resulted in an acute and reproducible pattern of infection. 36% of inoculated gerbils showed symptoms of infection after a first inoculation, whereas the second inoculation resulted in infection of 85% of the same gerbils. The group of SCID mice infected with ISO/90/2 failed to release cysts in the fecal material, while the second inoculated group infected with ISO/90/1 showed a low number of cysts at 13 days post inoculation. Cyst excretion was intermittent, mostly released during the second and the third week of infection. Mongolian gerbils are a useful animal model, whereas SCID mice are not, to assess viability and infectivity of parasites from various sources. Strain differences may contribute to the development of different pattern of infections, which lead to clinical consequences in the diagnosis of giardiasis.
Improving Mycobacterium spp. detection in water: a new methodological proposal
Authors: Santos R. , Gonçalves S. , Macieira F. , Oliveira F. , Rodrigues R. , Cadete M.
Published: May 2018

In recent years, non-tuberculous mycobacteria (NTM), once considered merely environmental saprophytes, have emerged as a major cause of opportunistic infections. There is no evidence of human-to-human transmission but they have been found in several environmental water samples. It is, therefore, of the utmost importance to develop methods of rapidly and accurately detecting non-tuberculous mycobacteria in water samples. To obtain a maximum recovery rate and a reduction of Mycobacterium spp. detection time in water samples, different decontamination, enrichment procedures and antibiotics supplements were tested before the inoculation into the Bactec® system. The proposed method of sample treatment (decrease in the decontamination time, followed for a peptone pre-enrichment step and an aztreonam and cefepime supplement) before the inoculation into the Bactec® system proved to be a good option for reliable and fast detection of Mycobacterium spp. in water samples.
Efficiency in water planning and management (an implementation experience)
Authors: Vojdani F.
Published: May 2018

Water is a primary factor in sustainable development; it may also be considered the most important component of economic and political power in contemporary world. Countries like Iran, which are located in arid and semi-arid regions of the world, since they are in permanent water crisis condition, must react by concentrating on research, pure studies and striving as far as possible to utilize water as optimally and manage water consumption. Lack of precipitation, inadequate infrastructure for collection, storage and recycling of water and above all, lack of public awareness regarding such issues as standard consumption patterns, force all countries like Iran to adopt strategic management policies and techniques toward such issues as water resources, maintaining and upgrading water quality, recharging of water resources and also other concepts, such as, “defined consumption”.

Although Tehran province enjoys having various surface and underground water resources, and also so-called scattered and undirected water resources such as Qanats, springs, treated waste water, etc., adding all these resources together, it still cannot quench its thirst. Average annual temperature and rainfall, and also explosive rate of population migration to the province, are main reasons of existing and widening gap between supply and demand. It seems the only alternative left is to capitalize and utilize various techniques to reduce consumption, otherwise Tehran will face a continuous and uninterrupted water crisis. Proposed strategic management viewpoint should also cover other areas such as supply, transfer, treatment, storage and also distribution and consumption. For each of above topics, special operational management should be considered and executed. Although, there were many reasons behind the recent water crisis, one of the main reasons was uncoordination among various management divisions which ended up in rationing. Tehran's water crisis was handled successfully by utilizing various strategic management techniques, but in order to prevent such crisis repeating itself, we must adopt long-term strategic policies and demand management, also various techniques of efficient use of water.
Comprehensive assessment of precursors, diagenesis, and reactivity to water treatment of dissolved and colloidal organic matter
Authors: Leenheer J.A.
Published: May 2018

A comprehensive isolation, fractionation, and characterization research approach was developed for dissolved and colloidal organic matter (DOM) in water, and it was applied to various surface- and groundwaters to assess DOM precursors, DOM diagenesis, and DOM reactivity to water treatment processes. Major precursors for natural DOM are amino sugars, condensed tannins, and terpenoids. Amino sugar colloids derived from bacterial cell walls are incompletely removed by drinking water treatment and foul reverse osmosis membranes, but are nearly quantitatively removed by soil/aquifer treatment. When chlorinated, amino sugars produce low yields of regulated disinfection by-products (DBPs) but they produce significant chlorine demand that is likely caused by chlorination of free amino groups. Condensed tannins are major precursors for ,blackwater- DOM such as that found in the Suwannee River. This DOM produces high yields of DBPs upon chorination, and is efficiently removed by coagulation/flocculation treatment. Terpenoid-derived DOM appears to be biologically refractory, infiltrates readily into groundwater with little removal by soil/aquifer treatment, gives low DBP-yields upon chlorination and is poorly removed by coagulation/flocculation treatments. Peptides derived from proteins are major components of the base DOM fraction (10% or less of the mass of DOM), and this fraction produces large yields of haloacetonitriles upon chorination.
Enhanced removal of natural organic matter via peroxidase-mediated oxidative coupling
Authors: Huang Q. , Pinto R.A. , Burlingame D.J. , Tang J. , Weber W.J.
Published: May 2018

Oxidative coupling reactions mediated by horseradish peroxidase in solutions containing natural organic matter (NOM) comprised by model fulvic acids were performed in completely mixed batch and flow reactors. The subsequent removal of NOM by ultrafiltration was found to be significantly enhanced for solutions subjected to oxidative coupling. Spectroscopic examinations revealed that the fulvic acid molecules were effectively reconfigured by substantial conversion of aromatic hydroxyl groups into ether bonds via oxidative coupling. These conversions apparently result in cross-linking of NOM moieties to form stable species of greater molecular size, thus rendering them more readily removable by ultrafiltration. The results of this study suggest that catalyzed oxidative coupling reactions in combination with ultrafiltration can be developed into an effective scheme for NOM removal in water treatment operations.
Problem of DOC removal during biological treatment of surface water with a high amount of humic substances
Authors: Juhna T. , Rubulis J.
Published: May 2018

Chemical precipitation in combination with biological treatment is a commonly used method for removal of turbidity and dissolved organic carbon (DOC) from drinking water. DOC is largely removed during biological treatment, which includes ozonation and filtration through a biologically active carbon (BAC) filter. Ozone converts humic substances into a biologically labile form that is mineralised by bacteria living in the following BAC filter. This study shows that this approach is often not efficient for removal of DOC from waters with a high amount of humic substances. During chemical treatment, the microbiologically available phosphorus is very efficiently removed, which results in shortages of phosphorus needed for bacteria to mineralise carbon in BAC filters. To enhance removal of DOC by biological treatment, addition of phosphorus prior to the BAC filters should be considered.
Effect of adsorption on filtration results of groundwater
Authors: Sallanko J. , Lakso E. , Lehmikangas M.
Published: May 2018

Groundwaters in Finland are soft and acidic, and the main substances that require treatment are iron and manganese. Iron removal is usually relatively easy by oxidizing dissolved iron into an undissolved form either by aeration or chemical oxidization and removing the formed precipitate by sand filtration, for example. If the raw water contains high amounts of organic matter, problems may arise when using the traditional methods for iron removal. In Finland it is quite common that groundwater contains both high levels of iron and humus. The groundwater of Kukkala intake plant in Liminka has been found problematic due to the high level of organic matter and therefore this research studied the removal of iron from this water by means of oxidation with hydrogen peroxide and filtration. Iron was oxidized with hydrogen peroxide and when the dosage reached 3 mg l−1, all iron was in trivalent form, which means that nearly all of it was in undissolved form, i.e. in fractions greater than 0.45 μm. Oxidized iron particles were, however, very fine and they could not be removed by sand/anthracite filtration. However sand/anthracite filtration was able to remove iron well without the feed of oxidation chemicals, and the iron was then led to the filter in bivalent dissolved form, thus the filter operated as an adsorption filter.
Benchmarking for water supply services focussing administration
Authors: Rapp S. , Günthert F.W.
Published: May 2018

In the discussion of fees for water supply services, companies are increasingly searching for effective measures to improve their economic management. Benchmarking is a management tool to identify room for improvement in undertakings. Focussing the processes in a water supply service can show measures to enhance the company's activities. A pilot project at the University of the Federal Armed Forces Munich was started in 2001 to test the method of Process-Benchmarking with two German water supply services. Therefore a system methodology was designed for water supply services with drinking water dams. Afterwards the systematic was successfully tested by implementing the companies' data. The administration of these undertakings was especially focussed in this project because it is a very large part of a company in respect to the employees and the amount of the expenses and its work has effects on all other parts. Room for improvements could be found for both water supply services and measures were designed to be implemented. The analysis of the administration in the described project was beneficial to raise the companies' efficiency. It showed that this method can be useful and is important for any other field of activity, too.
Enhancing an adsorption-membrane hybrid system with microground activated carbon
Authors: Matsui Y. , Fukuda Y. , Inoue T. , Matsushita T. , Aoki N. , Mima S.
Published: May 2018

The effects of particle size and mixing method of adsorbent during pretreatment in a microfiltration system were investigated. Micrometre-size powdered activated carbons (PACs) obtained by pulverization of an as-received PAC removed natural organic matter (NOM) from water much more efficiently than the as-received PAC, without additional membrane fouling and trans-membrane pressure buildup. The dosage of micrometre-size PAC required for pretreatment was one-sixth the equipollent dosage of the as-received PAC. The coagulant – PAC dosing sequence did not affect the extent of NOM removal, suggesting that the reduction of PAC-pore-blocking macromolecules by coagulation before PAC adsorption was not a key factor in improving the final extent of NOM removal. The mechanism of the enhanced adsorption by micrometre-size PAC seems to involve increases in the adsorption capacity itself, as well as increases in adsorption kinetics.
Effect of palladium on the reductive dechlorination of chlorinated ethylenes with nanoscale Pd/Fe particles
Authors: Lien H.-L. , Zhang W.
Published: May 2018

Direct injection of nanoscale iron particles represents a promising technology for in-situ groundwater remediation. Nanoscale Pd/Fe particles have been shown an excellent performance for degradation of a wide array of contaminants in groundwater. The objective of this study is to investigate the nature of palladium on the reductive dechlorination of chlorinated ethylenes using nanoscale Pd/Fe particles. Kinetics analysis indicated that nanoscale Pd/Fe particles increased dechlorination rates by 1–2 orders of magnitude compared to nanoscale Fe particles alone. XRD analysis and activation energy measurement suggested that the increase of reaction rates can be attributed to the catalytic property of palladium.
Relationship between di-(2-ethylhexyl) phthalate concentration and chemical structure of organic matter on solids in drinking water treatment processes
Authors: Thaveemaitree Y. , Nakajima F. , Furumai H. , Kunikane S.
Published: May 2018

Di-(2-ethylhexyl) phthalate (DEHP), regarded as a toxic substance, is widely used and abundantly contaminated in environments. Via contamination of freshwater, DEHP can enter into drinking water treatment and be adsorbed on solid particles. This study was aimed at understanding the concentration phenomenon of DEHP in drinking water treatment process, focusing on the relationship between DEHP concentration and characteristics of organic matter on the solids formed in the processes as scum, suspended solid and sludge. Solid samples were collected from five drinking water treatment processes in Japan and analyzed by pyrolysis GC/MS. The solids were categorized by the sampling locations, solid types and fragment composition. The specificity of the pyrolysis fragments in each group was summarized into a matrix. When compared with concentration of DEHP and characteristics of organic matter, a solid specifically containing many specific aliphatic fragments contained significantly high concentration of DEHP.
Network analysis models – the secret for success
Authors: Rogers D.M.
Published: May 2018

Water is a fundamental necessity of life. Yet water supply and distribution networks the world over are old and lacking in adequate maintenance. Consequently they often leak as much water as they deliver and provide an unacceptable quality of service to the customer. In certain parts of the world, water is available only for a few hours of the day. The solution is to build a mathematical model to simulate the operation of the real network in all of its key elements and apply it to optimise its operation. To be of value, the results of the model must be compared with field data. This process is known as calibration and is an essential element in the construction of an accurate model. This paper outlines the optimum approach to building and calibrating a mathematical model and how it can be applied to automatic calibration systems.
Approach for drinking water quality monitoring in rural areas: Morocco's case
Authors: Benqlilou H. , Laraki L. , Outair A.
Published: May 2018

Rural areas in Morocco are characterized by specific particulars dispersal, remoteness and importance. Considering this particular context, it is necessary to adjust the analysis and treatment methods, the monitoring and sanitary inspection systems. Within this framework, a new methodology was developed with the purpose of supervising and monitoring drinking water quality in rural areas. This methodology consists basically in applying common norms for rural localities bordering existing adductions, and in the adoption of a simplified approach for non-accessible rural localities supplied by autonomous drinking water systems. The simplified approach relies essentially on sanitary inspection data and on the control of parameters that constitute a sanitary risk in the short term (bacteriological parameters). The control of residual chlorine content is so important, for it ensures a high bacteriological quality of water and can offer the opportunity for a quick reaction of the manager. These two approaches are based mainly on resource protection, water disinfection and population awareness about the good use and preservation of water quality. Indeed, in order to ensure the continuity of rural autonomous drinking water systems in terms of quantity and quality of distributed water, various management models were developed: management by means of water user associations, and by a private operator. For these different modes of management, the methodology to adopt for supervising and monitoring drinking water quality in rural areas together with the attribution of tasks and responsibilities was already established. The right of citizens to sustainable and safe water is a stimulating challenge which requires the collaboration and involvement of all acting agents in the sector.
Assessment of real losses in potable water distribution systems: some recent developments
Authors: McKenzie R. , Seago C.
Published: May 2018

Considerable progress has been made over the past 10 years in the assessment and benchmarking of real losses in potable water distribution systems. Most of the advances have been based on the burst and background estimate (BABE) methodology, which was first developed in the mid-1990s by the UK water industry and has since been widely accepted and used in many parts of the world. Since the original BABE methodology was developed, several other key concepts have been added to the evergrowing list of water demand management tools. In particular, the infrastructure leakage index (ILI) and unavoidable annual real losses (UARL) introduced by A. Lambert, and the fixed area variable area discharge (FAVAD) theory by J. May, are now recognised as key “tools of the trade” in any water demand management assessment.

One of the first main developments where the above-mentioned concepts were applied in practice to benchmark leakage was in South Africa, where the local Water Research Commission supported the production of the BENCHLEAK Model. This was basically the first comprehensive model to assess real losses in potable water distribution systems using the UARL and ILI concepts. The model was developed by one of the authors together with A. Lambert, and was soon followed by similar developments in Australia (BENCHLOSS) and New Zealand (BENCHLOSSNZ). Both models incorporated additions and enhancements to the original South African model, and were tailored to suit the local conditions in line with the clients' requirements.

Similar developments took place in parallel by various leakage specialists, most notably in Brazil, Malaysia and Cyprus, to mention just a few of the similar initiatives. Each time a new model was developed, certain improvements were made and the “science” of leakage management and benchmarking was enhanced.

Through the use of the different models and from discussions with various researchers from around the world, it has become clear that there is a genuine need for such models, and they are being readily accepted by clients in most areas. The discussions have also raised many questions concerning the derivation of the terms used to calculate the UARL and the ILI, and, to address these concerns a specialist group was created through the IWA to investigate the various issues.

This paper will highlight the progress that has been made to date with regard to the key issues that have been raised by the task-team members, and recommendations based on the feedback that has been received from around the world. The paper will also present some of the results that have been obtained from different parts of the world to highlight both the progress and the problems associated with the assessment of real losses. The paper will conclude with a short description of several new models that have been developed and are in use, which demonstrate the latest improvements to an ongoing process to assess and benchmark real losses in water distribution systems.
Water reuse for the bottled water industry
Authors: Ramírez Camperos E. , Cardoso Vigueros L. , Escalante Estrada V. , Gómez Navarrete A. , Rivas Hernández A. , Díaz Tapia E.
Published: May 2018

The bottled water industry uses a machine specifically designed for the washing of its containers (19-L capacity) and generates 6-L wastewater/container. This effluent can be used for watering of green areas and car washing. The objectives of the present work were to characterize the effluent and to propose a specific treatment to enable reuse of the effluent from the container washing machine. The analysis of water quality identified the following problems: high pH (10.0), high biochemical oxygen demand (50 mg/L), high concentration of free residual chlorine (3.15 mg/l), alkalinity (207 mg/l as CaCO3) and hardness (38.8 mg/l as CaCO3). These parameters must be reduced in order to comply with the Mexican standards for water reuse (NOM-003-ECOL-1997), and to protect the washing equipment against corrosion and incrustations. The water can be used for the watering of green areas after pH adjustment and Biological Oxygen Demand (BOD5) removal. If special equipment is used for car washing, it is necessary to reduce the concentration of calcium and magnesium using a strong cationic resin. Following these recommendations the specific industry installed a treatment system with pH adjustment, dual filtration (sand-anthracite) and adsorption system with activated carbon. The effluent is now used for watering of green areas and for car washing with garden hoses.
Integrated failure forecasting model for the strategic rehabilitation planning process
Authors: Kropp I. , Baur R.
Published: May 2018

The occurrence of pipe failures in water networks cause major technical, economic and socio-economic impacts. Thus, comprehensible and reliable failure prediction models are required for operational and strategic planning purposes in order to guarantee a sustainable water network development. A lot of research work has been done in this field and the developed failure prediction models can be applied under various circumstances. However, most of the existing models have two major limitations: they consider a static state of the network without taking future developments into account, and they can hardly be applied to networks where only limited data on single pipe level is available. This paper describes a failure prediction model on the network and pipe type level, which is integrated in the KANEW framework for strategic rehabilitation planning. First testing results with this approach are promising.
A study on appropriate investment of pipeline rehabilitation for water distribution network
Authors: Asakura A. , Koizumi A. , Odanagi O. , Watanabe H. , Inakazu T.
Published: May 2018

In Japan most of the water distribution networks were constructed during the 1960s to 1970s. Since these pipelines were used for a long period, pipeline rehabilitation is necessary to maintain water supply. Although investment for pipeline rehabilitation has to be planned in terms of cost-effectiveness, no standard method has been established because pipelines were replaced on emergency and ad hoc basis in the past. In this paper, a method to determine the maintenance of the water supply on an optimal basis with a fixed budget for a water distribution network is proposed. Firstly, a method to quantify the benefits of pipeline rehabilitation is examined. Secondly, two models using Integer Programming and Monte Carlo simulation to maximize the benefits of pipeline rehabilitation with limited budget were considered, and they are applied to a model case and a case study. Based on these studies, it is concluded that the Monte Carlo simulation model to calculate the appropriate investment for the pipeline rehabilitation planning is both convenient and practical.
Low-pressure membrane filtration with unconventional coagulation regimes
Authors: Choi K.Y. , Dempsey B.A.
Published: May 2018

The objective of the research was to evaluate in-line coagulation to improve performance during ultrafiltration (UF). In-line coagulation means use of coagulants without removal of coagulated solids prior to UF. Performance was evaluated by removal of contaminants (water quality) and by resistance to filtration and recovery of flux after hydraulic or chemical cleaning (water production). We hypothesized that coagulation conditions inappropriate for conventional treatment, in particular under-dosing conditions that produce particles that neither settle nor are removed in rapid sand filters, would be effective for in-line coagulation prior to UF. A variety of pre-treatment processes for UF have been investigated including coagulation, powdered activated carbon (PAC) or granular activated carbon (GAC), adsorption on iron oxides or other pre-formed settleable solid phases, or ozonation. Coagulation pre-treatment is often used for removal of fouling substances prior to NF or RO. It has been reported that effective conventional coagulation conditions produced larger particles and this reduced fouling during membrane filtration by reducing adsorption in membrane pores, increasing cake porosity, and increasing transport of foulants away from the membrane surface. However, aggregates produced under sweep floc conditions were more compressible than for charge neutralization conditions, resulting in compaction when the membrane filtration system was pressurized. It was known that the coagulated suspension under either charge-neutralization or sweep floc condition showed similar steady-state flux under the cross-flow microfiltration mode. Another report on the concept of critical floc size suggested that flocs need to reach a certain critical size before MF, otherwise membranes can be irreversibly clogged by the coagulant solids. The authors were motivated to study the effect of various coagulation conditions on the performance of a membrane filtration system.
An assessment of wetland management scenarios: the case of Zazari–Cheimaditida (Greece)
Authors: Psychoudakis A. , Ragkos A. , Seferlis M.
Published: May 2018

This study suggests an integrated framework for the assessment of wetland management scenarios, based on a holistic approach of wetland ecosystems. All costs and benefits of management scenarios are estimated in terms of the value of wetland functions, which are indirectly valuated with a Contingent Valuation of goods and services they provide. The social impact of introducing the scenarios is also investigated with a stakeholder analysis, based on a survey. Scenario plausibility and acceptability are examined based on the results of the stakeholder analysis; on the other hand, the assessment of the scenarios, using cost-benefit analysis and multi-criteria analysis, provides quantitative performance indicators adequate to incorporate uncertainties and mutable policy objectives. This framework is applied to assess three management scenarios for a Greek wetland. The results indicate that the continuation of existing management practices is the most efficient alternative unless interventions for the restoration of wetland functions are conservatively budgeted, while a wetland drainage scenario performs poorly both in terms of economic efficiency and social impact.
Cost of services and willingness to pay for reliable urban water supply: a study from Delhi, India
Authors: Dutta V. , Tiwari A.P.
Published: May 2018

The provision of safe and universal water supply in an equitable and efficient manner is extremely important for urban water reform programs currently being carried out in developing countries. The sector reform not only requires a significant amount of working capital, but also people's willingness to pay for the improved infrastructure. This paper serves two purposes – first, it explains the meaning of ‘full-cost of water services’ in urban areas and attempts to provide a framework to value economic and environmental externalities for the urban water supply and use through a case study of India's capital city – Delhi. The second part uses contingent valuation method to establish people's willingness to pay from a survey of 1,100 households for water supply with better quality and reliability. Policy implications are subsequently discussed, keeping in mind cost of provision of water supplies. Also included is the assessment of the cost of unreliable supply (coping cost), which otherwise households are spending in the absence of a reliable supply. The paper shows several instances of reciprocal externality wherein the residents themselves absorb the cost of over-extraction, in terms of declining water tables, and cost of salinity in terms of decentralised treatment cost.
Efficient use of subsidies in the financing of water and wastewater investments
Authors: Almagro A.J.
Published: May 2018

Compliance with the European Union (EU) standards in the provision of water supply and wastewater services, as set forth in the relevant EU Directives, may require a significant investment effort for some countries and more specifically the new Member States. In order to ease this effort, these countries have the possibility of receiving subsidies from the European Commission to finance their investments. Using as a reference the standard methodology applied by the European Commission to define its intervention rate in a project, this paper focuses on the economic rationale and risks behind the investment subsidies in the sector. The questions asked are (a) what is the economic justification of this kind of investment subsidy and who are the target beneficiaries; (b) what factors may cause these subsidies to reach other economic agents; and (c) what measures would prevent those unexpected transfers of taxpayer resources. The results of the analysis indicate that, although the underlying methodology is economically sound, there is a significant risk that part of the subsidies may end up benefiting economic agents other than those originally targeted. However, this risk can be easily mitigated with some basic checks and balances during the calculation of the intervention rate. The views expressed in this paper are strictly personal.
Market-driven pricing structures for drinking water
Authors: Meij S.H.F.M. , Ruiters C.J.M. , Stumphius J.C.J.
Published: May 2018

In the Netherlands, water company sales are being driven down by water conservation measures adopted in households and by the emergence of feasible alternatives to mains water. Because the cost structure is largely fixed, prices are rising as a result. These developments are at odds with the community responsibility which water companies bear in their capacity as quasi-monopolists in relation to those of their customers who do not have access to alternative sources. A number of water companies are therefore working on new pricing structures with which they are seeking to stabilise their income and to reduce the financial appeal of switching to substitutes for mains water. At the same time, incentives designed to ensure sparing use in the consumer market should not disappear. Waterleiding Maatschappij Limburg is working on two new pricing structures. A cost allocation method has been developed for bulk users which can be used as a basis for setting customer-specific water tariffs. In addition, a generic structure is being developed to boost revenues from standing charges. More than previously, this structure makes earnings more dependent on the supply capacity installed on a customer's premises. In this article we discuss the background to these new structures and our initial experience. These pricing structures can also be employed in situations and countries where no noticeable reduction of sales has occurred yet, in order to keep ahead of the developments that are sketched here.
CanalEduca, a comprehensive educational project on the environment by Canal de Isabel II
Authors: Román Navarro N. San , Gómez Pérez M.P.
Published: May 2018

Canal de Isabel II, with over a decade of experience in the development of educational campaigns directed at schoolchildren in the first and second cycle of obligatory education (6 to 16 year-olds) in the Autonomous Region of Madrid, has developed and implemented, for the first time, an ambitious and comprehensive educational programme centred on environmental awareness in its broadest sense, making use of all the educational tools developed by new technologies and educational sciences, without any limit of age or boundaries. CanalEduca was established on this basis.
Optimization model for the Aguas Group drinking water production and main distribution network
Authors: Bianchi F.M. , Hyde J.F.
Published: May 2018

A model based on mixed-integer network optimization is developed and applied to the Aguas Group drinking water production and main distribution system. The four sanitary companies owned by the group, which supply nearly all Santiago, Chile, with drinking water, possess an intricate network of hydrological sources, water treatment plants, wells, pipelines and elevation plants, providing profuse alternatives to supply their clients. The Production and Main Distribution Optimization Model (MOPYT) searches for the global optimal provision scheme from an operational costs standpoint, specifically electricity, chemical inputs and extra labour expenses. The model provides weekly benchmarks for the diverse productive quarters. It has also been used for budgetary exercises planned for water demand forecasts. MOPYT has been particularly beneficial for generating consensus among complementary operational areas such as production and main distribution, achieving global costs efficiency.