bluuebunny/crossref_metadata_2025 huggingface dataset:
On the development of a high rate deep bed filtration unit
Authors: Lerch A. , Nahrstedt A. , Gimbel R. , Gray S. , Booker N.
Published: May 2018

Dispersed water contaminants with diameters less than 50 μm usually carry the greatest burden of contaminants that are of potential concern to the environment and human health in sewage. Microorganisms and viruses can be counted to this group of contaminants for instance. Furthermore, colloidal water contaminants possess a higher specific surface area per unit mass which can enable the accumulation of possibly problematic dissolved water contaminants onto this area. Therefore, efficient removal of contaminants from wastewater relies on the efficient removal of fine particles and colloidal material from water. The CSIRO Molecular Science has been developing the idea of using high rate deep bed filtration through porous plastic media to improve the separation of suspended and colloidal particles from sewage. Because the IWW was aspiring an analogous technology by developing and modelling deep bed filtration with permeable synthetic collectors (PSC), the possibility for collaboration in a research project was given. The project investigated the use of a dual stage filter media system with upwards directed flow. The aim of using this system was to achieve high total suspended solids (TSS) removals and high turbidity storage capacities at fast filtration rates (20-50 m/h) while simultaneous decreasing the dose of flocculation chemicals to its minimum.
Comparative performance of an electrocoagulation/flotation system with chemical coagulation/dissolved air flotation: a pilot-scale trial
Authors: Jiang J.Q. , Graham N.J.D. , André C.M. , Kelsall G.H. , Brandon N.P. , Chipps M.J.
Published: May 2018

An electrocoagulation-flotation (ECF) pilot plant was designed, built and operated to evaluate its performance in comparison with a pilot scale conventional dissolved air flotation (DAF) system for treating lowland surface water in the UK. Treatment performance was assessed principally in terms of changes in dissolved organic content (DOC) and system running cost. On average, the decrease in DOC, UV-254 and colour was 10-15% with ECF at pH ca. 7.8 and current densities of 2-5 A m-2 (equivalent dose range of 1-5 gAl(III) m-3). Acidification of the influent (pH 8.4 down to 7.5) decreased only DOC and increased apparent current efficiencies for Al dissolution above unity. Passivation of the aluminium electrodes by Al(III) (hydrous) oxides caused difficulties in maintaining a steady dissolved Al(III) concentration and also increased specific electrical energy consumptions. Treated water quality with ECF was as good as that with DAF at lower equivalent coagulant doses (< 5 gAl(III) m-3), but was less so at higher coagulant doses. The pilot-plant DAF system appeared to be more expensive in terms of its running cost for the conditions used; the cost ratios of DAF to ECF were between 3:1 and 5:1, respectively, for an equivalent treatment performance.
The effect of distribution system biofilm bacteria on copper concentrations in drinking water
Authors: Critchley M.M. , Cromar N.J. , McClure N. , Fallowfield H.J.
Published: May 2018

This study investigated the potential for distribution system biofilm bacteria to elevate copper concentrations in drinking water. Biofilms were sampled from household copper reticulation pipes and grown on R2A agar. Laboratory coupon experiments were used to determine the effect of single isolate biofilms on aqueous copper concentrations. The majority of biofilm bacteria did not affect copper concentrations in comparison to sterile controls. However, several bacteria including Acidovorax delafieldii, Cytophaga johnsonae and Micrococcus kristinae were shown to significantly elevate copper concentrations in drinking water. In contrast, the bacteria Rhodococcus sp. and Xanthomonas maltophilia were shown to significantly decrease copper levels in comparison to controls. The significance of biofilm bacteria to increase copper concentrations in drinking water has implications for public health by increasing concentrations to levels toxic to humans.
Structure of Al-humic flocs and their removal at slightly acidic and neutral pH
Authors: Wang X.C. , Jin P.K. , Gregory J.
Published: May 2018

Using microscopic and optical monitoring techniques, the process of coagulation of humic substances was studied paying attention to the structure of flocs and their settleability and filterability with information from image analysis, and HPLC, zeta potential, TOC and UV absorbance measurements. The results show that Al-humic flocs formed at pH 5.0 appear more compact with higher fractal dimension while those formed at pH 7.0 are looser with lower fractal dimension. During growth, Al-humic flocs also undergo a decrease in their fractal dimension. The attainable removal of TOC is about 40-50% at both pH values, but the optimum Al dose at pH 7.0 is about 5 times of that at pH 5.0. Charge neutralization is believed to be the main mechanism of coagulation at pH 5.0 and sweep coagulation plays an important role at pH 7.0 as well as at pH 5.0 under an overdosing condition.
Characterization and destabilization of spent filter backwash water particles
Authors: Adin A. , Dean L. , Bonner F. , Nasser A. , Huberman Z.
Published: May 2018

Inorganic and organic particles, including bacteria, viruses and parasites, which are retained within a granular filter during surface water filtration, are removed by backwashing the filter with clean water or water and air. The objective of the study was to characterize SFBW and determine its treatability by coagulation. Microbial and physical-chemical characterization of SFBW collected from a number of different water treatment plants was performed. Experiments to determine the impact of coagulation/flocculation on the SFBW samples were also conducted. SFBW was collected from six different water treatment plants and analyzed for microbial and physical parameters. Physical characterization was done on SFBW collected from all of the treatment plants. Turbidity and pH measurements were taken over the course of the backwash run, and the backwash samples were collected in two to four 20 L containers. A number of parameters were measured for the samples in each container, as well as for SFBW composites made by mixing equal portions of the container contents. The measured parameters included: turbidity, pH, TSS, DOC, UV-254 and alkalinity. Jar tests were carried out on individual containers, on SFBW composite and on SFBW composite that was allowed to settle for one hour. Turbidity and particle count data was collected for both settled and filtered samples.
System development and testing of wind-powered reverse osmosis desalination for remote Pacific islands
Authors: Liu C.C.K. , Migita R. , Park J.-W.
Published: May 2018

Reverse osmosis (RO) is one of the most feasible methods of desalination to produce a supplemental freshwater supply. Because traditional RO desalination is energy-intensive, it is not a viable solution for remote Pacific islands where electricity is also in short supply. The utilization of wind power holds promise as a solution to this problem, as most of these remote islands are subject to constant trade winds. RO desalination of brackish groundwater, which is available in many of these islands, requires low feed water pressure that can be delivered by wind power at a moderate wind speed. Testing of a prototype wind-powered RO desalination system constructed on Coconut Island, a small island off the windward coast of Oahu, Hawaii, indicated that at an average wind speed of 8.5 m/s, a freshwater flow of over 4000 L/d can be produced. This volume is sufficient to meet the freshwater needs of a typical remote island community.
Pilot plant study on the performance and optimization of submerged membranes for taste and odor removal
Authors: Schideman L. , Snoeyink V.L. , Mariñas B.J. , Kosterman M.
Published: May 2018

Hybrid sorption-membrane processes are an attractive alternative for meeting a range of water treatment goals in a single process that is compact and cost-effective. This study investigated the performance and optimization of a hybrid sorption-membrane process using powdered activated carbon (PAC) and submerged-style membranes for odor control. Specifically, this study focused on the removal of 2-methylisoborneol (2-MIB) from a Lake Michigan source water and investigated the effects of PAC dose, dosing method, backwash interval, and aeration. Adsorption performance was predicted using a mathematical model, and tested using a pilot-scale, submerged membrane system. Modeling continuously dosed PAC performance agreed well with pilot results, but pulse dosed PAC performance was overestimated by the model. Non-ideal mixing effects were identified as important factors in explaining the pulse dosing results. Pilot results with aeration and pulse dosing were also overestimated by the model. It is hypothesized that aeration disturbs the PAC cake layer that forms on the membrane, and thus eliminates the beneficial effects that this cake layer can have on adsorption. Extending backwash intervals from 30 to 180 minutes with continuous dosing increased the percent removal of 2-MIB by up to 30% in both the model predictions and pilot results. This study highlights some important considerations in the design of full-scale systems and future mathematical models.
Denaturing gradient gel electrophoresis analysis of a methyl tert-butyl ether degrading culture applied in a membrane bioreactor
Authors: Pruden A. , Suidan M. , Morrison J. , Venosa A.
Published: May 2018

A membrane bioreactor (MBR) was operated for the removal of methyl tert-butyl ether (MTBE) from water. Although the reactor was seeded with several cultures acclimated to MTBE degradation, a long start-up time was observed. Monitoring of the reactor with denaturing gradient gel electrophoresis (DGGE) revealed a dramatic shift in the MBR culture from the original seed culture, indicating that the membrane had exerted a selective pressure on the culture. The MBR culture was found to be dominated almost entirely by Sphingomonas, belonging to the a-4 subclass of the a-Proteobacteria. Several unique properties of Sphingomonas, including their characteristic outer membrane containing glycosphingolipids, as well as their extreme adeptness at xenobiotic degradation are hypothesized to have aided in their selection in this bioreactor.
Estimating Giardia cyst viability using RT-PCR
Authors: Maux M. , Bertrand I. , Gantzer C. , Schwartzbrod J.
Published: May 2018

The aim of this work was to evaluate the use of molecular techniques for the detection of viable Giardia cysts in the environment to assess public health issues. Three target genes were selected: the heat shock protein gene, HSP70, which is expressed in response to stress; the giardin gene, which encodes a structural protein; and, alcohol dehydrogenase E (ADHE), a novel gene encoding an enzyme involved in the metabolism of energy. We tested the efficiency of five protocols for the extraction of either genomic DNA or total RNA from Giardia cysts: two of these protocols were previously cited in the literature and three consisted of commercial DNA extraction kits. The brands of enzyme were determined according to the primers chosen and the amplification conditions were optimised: 2.5 mM MgCl2, 0.5 mM primers and 60°C for annealing temperature. A semi-nested PCR method and an RT semi-nested PCR procedure were developed to detect mRNA from these three genes and to estimate the viability of Giardia cysts.
Back to pre-disinfection of highly polluted waters
Authors: Narkis N. , Katz-Stoller A.
Published: May 2018

The initial pre-disinfection was one of the stages that most contributed to the formation of a large number of halogenated disinfection by-products (DBPs). The threat and awareness to the formation of chlorine disinfection by-products, refrained from using pre-disinfection with chlorine in the treatment of contaminated raw waters, to be used as drinking water. The main purpose of this research was to study whether chlorine dioxide can be used for pre-disinfection in the treatment of highly polluted wastewaters and surface waters. Chlorine dioxide was found suitable, as a replacement for chlorine, for disinfection of water containing natural organic substances, effluents’ organic materials and ammonium ions, due to its advantages, and especially because it is an effective disinfectant for killing pathogenic microorganisms and destroying viruses. Chlorine dioxide does not form THMs and barely creates chloroorganic compounds. However, the main disadvantage of the chlorine dioxide is the creation of undesirable chlorite and chlorate ions, which are suspected of being toxic. This research showed that the undesirable chlorite ions can be removed completely by adding Fe+2, which reduces ClO2- to the harmless Cl-, and is oxidized to Fe+3, to form the ferric polyhydroxo complexes, that can be used as the flocculant, in the next flocculation step, for the achievement of safer drinking water.
THM formation during chlorination of treated municipal wastewater
Authors: Koukouraki E. , Diamadopoulos E.
Published: May 2018

Chlorination batch experiments were conducted in order to estimate the concentration of THM and their formation potential in nitrified and partially nitrified secondary effluent. The role of contact time (up to 2 hours), chlorine dose (3 levels), pH and temperature on the formation of THM was evaluated. THM formation, as measured by individual concentration as well as formation potential, was high for the nitrified secondary effluent, while for the partially nitrified effluent the respective concentrations were low, due to the reaction of chlorine with ammonia to form chloramines. In general, THM concentrations progressively increased as contact time, pH and chlorine dose increased. Increase in temperature (from 15-25°C) showed a rather limited effect. In addition, coagulation tests were applied prior to chlorination of the nitrified effluent for removing organic carbon and thereby controlling the formation of THM. Alum was used as the coagulant in doses varying from 0.1 mM to 2.5 mM. As the coagulant dose increased, the removal of both DOC and absorbance at 254 nm increased, while THM formation decreased. The reduction in THM formation was more pronounced for coagulant doses higher than 1.5 mM.
An integrated approach to assess the causes of water quality failures in the distribution system of Caen
Authors: Jaeger Y. , Gauthier V. , Besner M.-C. , Viret B. , Toulorge R. , Lemaire E. , de Roubin M.-R. , Gagon J.-L.
Published: May 2018

Understanding the reasons for water quality failures in drinking water distribution systems has become a priority for network managers. The proposed approach provides a unique tool for assessing the consequences of water supply changes and the consequences of distribution system operation and maintenance on the quality of distributed water. Its main benefit is to help the water producer understand the origins of local water quality problems, and consequently to eliminate them from their distribution system.
Selecting and scheduling infrastructure rehabilitation projects
Authors: Baur R. , Kropp I.
Published: May 2018

Targets for the condition and performance of water supply networks can be formulated from quantitative needs as well as from the demand for the quality and reliability of drinking water networks. To reach these objectives, a public or semi-public utility needs to invest in system maintenance and rehabilitation. For the system analyst it is difficult to give specific action threshold values for each indicator describing the network performance. Preferences differ and interdependencies between criteria do not allow, by conventional scoring models, determination of those projects which are the most efficient. Another method is presented for ranking rehabilitation projects according to multiple criteria with respect to efficiency. The development of the procedure and its implementation in software is part of a research project funded by Deutsche Forschungsgemeinschaft (DFG).
Life cycle assessment of water mains and sewers
Authors: Herz R.K. , Lipkow A.
Published: May 2018

Ecological aspects have gained increasing attention during recent decades in urban land use planning and site development. However, relatively little attention has been paid so far to mass and energy flows of urban infrastructure and utility systems in particular, in spite of their significant contribution to the total mass. In the first part of this paper, the mass of water mains and sewers is quantified in relation to the mass of buildings. The second part of the paper deals with the development of the stock of water mains and sewers from the past to the future. Future rehabilitation needs in terms of annual mileage of pipelines reaching the end of their service life are forecast with a cohort survival model. In the third part of the paper, some preliminary results are presented on the mass and energy flows of water mains and sewers. Conventional life cycle assessment methodology is applied to pipelines of different materials.
Establishment of an effective renewal method for externally corroded distribution pipes
Authors: Suzuki M. , Honda H. , Saka S.
Published: May 2018

In Japan, generally, the lifetime of distribution pipes (ductile cast iron pipes) is considered to be 40-50 years. However, starting in 1973 in Sapporo, leakage incidents, owing to corrosion on external surface of pipes and joint bolts, started to be found in ductile cast iron pipes which had been laid for less than 10 years. Therefore we have covered the entire length of newly laid pipes with polyethylene sleeves as an anti-corrosion measure. However, leakage incidents caused by external corrosion occurred occasionally along a total of 856 km of distribution pipes laid before this measure started. Such a problem of widespread maintenance of externally corroded distribution pipes was quite rare in Japan. We investigated the cause of external corrosion and corrosion situations and derived the formula to predict depth of external corrosion. Consequently, we established an effective renewal method by building an externally corroded pipe danger map to give renewal priority to externally corroded distribution pipes depending on leakage possibility.
Fouling and accuracy drift of water meters
Authors: Hofman J. , Brink D. , Breure P. , van der Hoek J.P.
Published: May 2018

In 1997, the Amsterdam City Council decided that water meters should be installed in every house connection. With this decision Amsterdam Water Supply (AWS) was faced with the challenge to install approximately 475,000 water meters and adapt its organisation to fulfil all customer services. Among the technical challenges was the selection of the type of meter to be used. Since AWS had only limited experience with water meters, a selection study was conducted. The main focus of this study was to estimate the life time, robustness, and accuracy drift of meters with different measuring principles. Several tests were conducted to estimate the meter's lifetime, but also fouling layers in the meter house and mechanism were examined. From the research it was concluded that meters based on a volumetric measurement were most accurate, and showed less susceptibility to fouling. Estimated lifetime of these meters was 10-12 years.
Evaluation of a package plant for small communities in Mexico
Authors: Pavón Silva T. , Hoyos S.G. , Chávez Guerra C.
Published: May 2018

The design and operation of floc blanket clarification plant, embodying coagulation, flocculation and floc blanket sedimentation is still very much an art, mainly because there has been no adequate scientific explanation of the mechanisms of the floc blanket sedimentation process. This study aims to provide an explanation based on the floc blanket formation with CPL (hydroxyl chlorine of aluminium) coagulant. The theoretical parameters results were: Gcoagulation: 1,500 s-1; Gflocculation: 397 s-1, and for sedimentation G×θ×c 2476.8. The solid removal in the floc blanket was 65.28% expressed by residual turbidity. The water quality obtained at the end of the treatment satisfied the values of official Mexican standards.
International Report: Performance assessment in the water industry
Authors: Merkel W.
Published: May 2018

National contributions from 16 countries and additional information were used for an international state-of-the-art report on performance assessment (PA) in the water industry. The purposes of this international report are i) to discuss areas of PA within the water supply and wastewater sector, ii) to analyse aspects of practical relevance and iii) to look on future trends and developments. Several aspects of PA are discussed, such as the quality and the availability of data, the importance of definitions and explanatory factors, the use of information from PA, and practical aspects such as willingness to participate and costs. Standardised PA frameworks of the International Water Association (IWA), the World Bank, and the Water Utility Partnership are presented, and an outlook on research and development of PA tools is given.
Business partners for development-KwaZulu-Natal pilot project, South Africa: a new approach to the delivery of sustainable water and sanitation services in poor peri-urban areas
Authors: Rousseau P. , Tranchant E.
Published: May 2018

An innovative tri-sector partnership has been formed in two peri-urban areas in Durban and Pietermaritzburg, in the province of KwaZulu-Natal, South Africa, which aims to provide sustainable water and sanitation services to these previously disadvantaged communities. This forms part of the world-wide Business Partners for Development (BPD) programme initiated by the World Bank to bring together the diverse resources, expertise and perspectives of three distinct sectors: business sector, public sector and civil society, in particular Non-Governmental Organisations (NGO's). The project focus includes infrastructure upgrading, water loss management, community involvement and capacity building, education and awareness on water conservation, health and hygiene, and customer management. The establishment of a common research framework examining impacts and outcomes and an international sharing and learning programme will, it is hoped, lead ultimately to better and replicable practices.
Riverbank filtration for drinking water supply - a proven method, perfect to face today's challenges
Authors: Irmscher R. , Teermann I.
Published: May 2018

Hygiene standards and parasites have been a special focus of drinking water utilities for several years. In this context the development of new, high-tech water treatment methods is often taken into consideration. However, we have been applying riverbank filtration as an inexpensive, natural method in Düsseldorf for over 130 years. Indeed it had been introduced for “hygiene reasons” at the time and, according to our experience, riverbank filtration is well suited to meet these “new” hygiene challenges. We have intensively examined the infiltration of river water into the aquifer. We view this core process as the prerequisite for the sustained function of riverbank filtration. It is closely linked with the retention of turbid matters in the riverbed and the shearing forces on the subsurface. In addition, we have investigated the effectiveness of bank filtration as regards the elimination of microorganisms over recent years. According to these examinations, bacteria are reduced by an average of 3 log orders by bank filtration; individual breakthroughs correlate with high water events. According to our measurements Giardia and Cryptosporidium have been completely eliminated in riverbank passage. The retention of three examined types of viruses was also found to be almost completely accomplished.
Oxidation of manganese in drinking water systems using potassium permanganate
Authors: Raveendran R. , Chatelier B. , Williams K.
Published: May 2018

South Gippsland Region Water Authority experience manganese problems in most of their surface water reservoirs. Manganese is present in the form of manganese(II) ions and manganic dioxide solids. At low dissolved oxygen levels, the manganic dioxide is reduced to the manganese(II) ion. If not oxidised, the manganese(II) ion escapes through water treatment facilities and enters the supply system. Once in the system, the manganese ions are gradually oxidised to insoluble manganic dioxide causing dirty water problems which can stain clothes and bathing equipment. As part of the water treatment process, manganese(II) can be oxidised to insoluble manganic oxide and then removed by clarification and filtration. Generally, oxidation can be achieved by aeration or chemical oxidation by addition of an oxidising agent such as potassium permanganate (KMnO4) or chlorine. However, due to fluctuations of manganese levels in raw water, treatment techniques are often very difficult. This paper shares the experiences of South Gippsland Water in using potassium permanganate as part of the water treatment process to remove manganese in its surface water reservoirs. Whilst consideration is given to the advantages and disadvantages of alternative oxidation methods, this paper primarily focuses on the use of KMnO4 to remove manganese and the resulting analytical problems associated with monitoring manganese levels.
Integration of water treatment, environmental and information technologies: Amagasaki project
Authors: Hanamoto T. , Nagashio D. , Sasaki T.
Published: May 2018

The Hanshin Water Supply Authority (HWSA) supplies drinking water to approximately 2.4 million consumers in the Hanshin area, including the city of Kobe. The HWSA has completed a project integrating two aging plants into a new water treatment plant (Amagasaki WTP) with a capacity of 373,000 m3 per day. The Amagasaki WTP has three significant special merits: water treatment, environmental, and information technology. The water treatment system is based on a multiple-barrier concept that estimates the value of water treatment technology not by individual processes, but by the overall performance of the system. The treatment train consists of coagulation/sedimentation, ozonation/activated carbon fluidized-bed adsorption, and coagulation/high-rate filtration, most of which fully utilize upward-flow. The key environmental technology characteristic of the new WTP is its achievement of zero-emissions. This design reduces CO2 discharge from the plant, as well as making it possible to completely recycle the sludge as an alternate material of agricultural and horticultural soils. Improvement of customer relations is a feature of the information technology. The authority provides information on the safety of the finished drinking water, watershed management, and the maintenance of source water quality. A visitors' area and emergency water supply facility for use in disasters have also been set up at the WTP. The Amagasaki WTP started commercial operation in April 2001. The completion of this renovated plant will significantly raise the quality of service to the customers.
Development of an integrated iron oxide adsorption/membrane separation system for water treatment
Authors: Lee K.-W. , Choo K.-H. , Choi S.-J. , Yamamoto K.
Published: May 2018

The performance of an integrated iron oxide particle (IOPs) adsorption and ultrafiltration (UF) process was investigated in terms of natural organic matter removal and membrane permeability during treatment of a drinking water source. Throughout the fractionation of raw water and subsequent UF of fractioned portions, the significance of each component in raw water affecting flux decline during IOP-UF was evaluated. Natural organic matter (NOM) removal efficiencies for the IOP-UF system increased markedly as a substantial amount of IOPs was added into suspension, without any negative effect on permeate flux. During IOP-UF testings, there was no difference in NOM removal regardless of the locations of IOPs whether they were either in suspension or deposited on the UF membrane, but significant initial flux reduction occurred with the formation of a precoat (attached) layer. However, all IOPs in suspension and in the cake were effective in both removing NOM and preventing irreversible fouling as long as they were removed by backwashing. Dissolved matter obtained from filtration through a 0.45 μm filter was more responsible for flux decline in UF than larger colloids. Particularly, IOP-adsorbable dissolved matter accounted for 60% of total flux decline, confirming the attractiveness of IOP addition to UF.
Coagulation as a pretreatment of SFBW for membrane filtration
Authors: Nasser A. , Huberman Z. , Dean L. , Bonner F. , Adin A.
Published: May 2018

Granular filtration has been incorporated as a major barrier to prevent the dissemination of disease-causing agents by drinking water. Particles and pathogens such as Giardia lamblia and Cryptosporidium parvum retained in the filters are then washed by utilizing clean water. This study was conducted, primarily, to evaluate coagulation as a pretreatment for the Spent Filter Backwash Water (SFBW) treatment by ultrafiltration (UF). SFBW Samples were collected from four different water treatment plants and carefully analyzed. Jar-tests and backwash pilot studies were performed in the laboratory. Depending on the water source, protozoan parasites and viruses were found to be prevalent in SFBW. The results show that turbidity cannot serve as a surrogate for the microbial load of the SFBW. Alum flocculation pretreatment of SFBW was found to be effective in reducing turbidity, particle count, viruses and parasites, consequently it may also reduce membrane fouling. Settling the SFBW prior to flocculation did not enhance the removal of turbidity and particle count as compared to the unsettled SFBW samples. This finding might imply that settling would not be required prior to UF. The largest remaining particle fraction after alum flocculation was 3-10 μm in size, both Cryptosporidium and Giardia are found in this size range. Coagulation enhanced the removal of small size particles and may result in extending the filtration cycle by reducing the SFBW fouling potential.
Community experience and perceptions of water reuse
Authors: Marks J. , Cromar N. , Fallowfield H. , Oemcke D.
Published: May 2018

The experience and perceptions of 80 people residing in four separate sites, which feature reclaimed water systems, are considered in this paper in relation to the benefits and costs of residential water reuse applications. Reclaimed water is used for non-potable applications by residents in Florida mainly for garden irrigation and in Australia for both irrigation and toilet flushing. All respondents value reclaimed water and although the benefit of water conservation is identified they are more enthusiastic about the personal cost benefit involved in using this cheaper alternative to potable water. Many are willing to handle the water but the extent to which this increased exposure is seen as a good development depends on the quality of information provided to users. In relation to reclaimed water for toilet flushing, there is a strong indication that the water conservation and cost saving benefit is small compared to the initial cost and the increased cross connection risk.
Membrane filtration retentate thickening efficiency using electrolytic ion products instead of chemical coagulants
Authors: Huang J.Y. , Uchiburi T. , Fujita K.
Published: May 2018

Electrolytic coagulation has advantages compared with conventional chemicals coagulation treatment. First of all, the addition of alkaline agent is necessary in chemicals coagulation treatment as the addition of acid agents in coagulation of dense wash water makes pH decline. While not much change of pH is observed with electrolytic coagulation, where alkaline agent is not demanded. Secondly, it is easy to control the dose of additional coagulants. In this study, electrolytic coagulation sedimentation treatment is adopted for membrane retentate from membrane filtration treatment without using coagulants. As electricity can control the addition of coagulation, an automation method is applied in the experiment. The lower the iron as well as aluminum dissolved, the higher the sludge density becomes; especially aluminum has this tendency. It is possible to achieve 400 kg/m3 of condensed sludge density with artificial wash water and more than 80 kg/m3 for real retentate, in terms of electrolytic coagulation of iron anode. The sludge density of aluminum anode is higher, but its filtrate density is lower than iron anode.
Decline of residual chlorine in artificial stream flow sustained by reclaimed wastewater: field study in Sapporo
Authors: Funamizu N. , Iwamoto T. , Takakuwa T.
Published: May 2018

Among several applications of urban wastewater reuse, use of reclaimed wastewater to sustain stream flows has become attractive especially in urban areas. This environmental application of reclaimed wastewater occupies about 32% of total wastewater reuse in Japan. In this paper, residual chlorine in the full-scale project for environmental application in Sapporo was discussed. The field survey of residual chlorine showed that there was the hourly variation of residual chlorine concentration in the river and this variation depended on the hourly variation in composition of chlorine species in the effluent of the WWTP, and that the rate of decline of residual chlorine in the open channel section was greater than that in the pipe flow section. The simple mathematical model was developed for describing the decline process on the basis of the dispersion model including two reactions: interaction of residual chlorine and organic matter in reclaimed water and interaction of chlorine and pipe surface or bio-film. The expressions for these two reaction rates were obtained by lab-scale experiments and these calibration results showed that consumption rate of residual chlorine in the aqueous phase was comparable to the rate on the pipe wall in the pipe flow section, and that residual chlorine in the open channel was consumed mainly by bio-film. The calibrated mathematical model yielded a good estimation of the chlorine concentration profile.
Water reuse and zero liquid discharge: a sustainable water resource solution
Authors: Durham B. , Mierzejewski M.
Published: May 2018

Increased water demand from population and economic growth, environmental needs, change in rainfall, flood contamination of good quality water and over abstraction of groundwater are all factors that will continue to create water shortage problems. This paper considers alternative solutions, which conform to sustainable solution premises whilst being economically beneficial to the community. The importance of pilot studies is reviewed and the surprises they can uncover. Case studies describe the benefits of long-term operating experience of zero discharge systems reusing the wastewater produced by car manufacture and secondary sewage reuse for a large coal fired power plant. Applications of reuse on large islands such as Hawaii and desert communities are discussed including the production of cash crops with high efficiency irrigation systems by reusing brackish municipal wastewater. Large municipal zero discharge potable water production is also described with an economic comparison of the alternatives.
Comparative design and performance analysis of three different in configuration waste stabilization ponds pilot units in a Mediterranean-temperate climate
Authors: Parissopoulos G.A. , Papadopoulos A. , Papadopoulos F. , Karteris A.
Published: May 2018

The performance of three waste stabilization ponds (WSP) treatment units (lines A, B, C) for a period of two years is presented. The above units were part of a research and demonstration project in North Greece concerning wastewater treatment with natural systems and effluent reuse for irrigation. Line A consisted of a deep anaerobic pond followed by a facultative and two maturation ponds. The anaerobic pond supplied with 120 m3/d was also feeding line B at a ratio 1:3 (line A: line B). Line B had the same design features with line A but with a recirculation of effluent. The third unit fed with primary treated effluent at a rate of 50m3/d from the WWTP of Thessaloniki was consisted of a facultative and two maturation ponds. In the anaerobic pond the BOD5, COD, SS, TC and FC mean reduction was 28%, 42%, 58%, 31% and 36% for the cold period (T<10°C) and 45%, 53%, 72%, 67% and 71% for the warm period (T>10°C) respectively. In line A, the BOD5, COD, SS, TC and FC total reduction was 98%, 89%, 93%, 99.99% and 99.99% for the cold and 98%, 85%, 88%, 99.99% and 99.99% for the warm period. In line B the reduction was 92%, 86%, 88%, 98.5% and 98.82% for the cold and 96%, 88%, 83%, 99.95% and 99.97% for the warm period. In line C the reduction of the same parameters was 92%, 64%, 40%, 99.88% and 99.96% for the cold and 92%, 59%, 22%, 99.99% and 99.99% for the warm period. The effluent quality was further improved with the use of a storage reservoir and a slow sand filter and reused successfully for crop irrigation.
Combining UASB technology and constructed wetland for domestic wastewater reclamation and reuse
Authors: El-Khateeb M.A. , El-Gohary F.A.
Published: May 2018

The enhancement of water quality by constructed wetland systems is increasingly being employed throughout the world. For this study two treatment schemes consisting of an Up-flow Anaerobic Sludge Blanket (UASB) reactor followed by either subsurface flow (SSF) or free surface flow (FSF) constructed wetlands have been investigated. The common macrophyte in Egypt Typha latifolia (cattail) was used at a planting density of three rhizomes/m2. To evaluate the role of plants in the treatment process, an unplanted gravel bed identical to the SSF unit was operated as control. During the study period, the wetlands were fed with the UASB effluent at an organic loading rate ranging from 17.3 to 46.8 kg BOD5/ha·d (55.1 to 134.6 kgCOD/ha·d). Effectiveness of the system for the removal of key constituents (COD, BOD, TSS, nutrients and FC) has been investigated. The results showed that, the level of CODtot, and TSS in the final effluent of SSF was lower than that of FWS. Subsurface flow wetland has demonstrated higher overall efficiency than the unplanted control. FC reduction reached 4 log units. Further studies are on-going to optimize the wetland design under local environmental conditions.
Reduction of pathogens, indicator bacteria, and alternative indicators by wastewater treatment and reclamation processes
Authors: Scott T.M. , McLaughlin M.R. , Harwood V.J. , Chivukula V. , Levine A. , Gennaccaro A. , Lukasik J. , Farrah S.R. , Rose J.B.
Published: May 2018

The need for alternative sources of water, especially for non-potable purposes, has been met in many states in the US and throughout the world through the use of reclaimed wastewater. Wastewater contains a wide variety of microbial pathogens that may pose a risk to human health if not properly controlled; however, there are currently no national standards for microorganisms or consistent treatment requirements in the US with regards to reclaimed water. Besides the routine monitoring for TC and FC bacteria that has been used for assessing water quality, several types of alternative microorganisms have been suggested as indicators of water quality, fecal pollution, and public health risks. These include enterococci, Clostridium perfringens, and coliphage among others. This project evaluated the removal of both indicators (TC and FC, enterococci, C. perfringens and coliphage) and pathogens (enteroviruses, Giardia spp. and Cryptosporidium spp.) at 3 water reclamation facilities with varying treatment designs and operations. The facilities evaluated range in size from 20 to 44 million Liters per day capacity, with both shallow and deep bed sand/anthracite filters. Differences also existed in the disinfection processes for the 3 reclamation plants. The TC and FC showed a 5 to 7 log reduction throughout the treatment processes with no detectable levels in the final effluent. However, even though the alternative indicators (enterococci, C. perfringens and coliphage) showed reductions that varied from 2 to 6 logs, some levels of these indicators were consistently detected in 2 of the 3 facilities in the final reclaimed effluent. Both Cryptosporidium spp. and Giardia spp. were detected in the final effluent in all 3 facilities, even when no indicators were present. Virus detection was seasonal, and associated with cooler temperatures and less disinfection. The results of this study indicate that differences in filter design, operations, and disinfection approaches were responsible for differences in inter and intra facility water quality variability.
Evaluation of the UV disinfection process in bacteria and amphizoic amoebae inactivation
Authors: Maya C. , Beltrán N. , Jiménez B. , Bonilla P.
Published: May 2018

Every year around 3.4 million people die from water-related diseases, mainly amoebiasis and diarrhoea caused by bacteria. The assessment of the efficiency of a UV light disinfection process in the inactivation of indicators, pathogen bacteria and amphizoic amoebae in a secondary treated effluent was carried out. Wastewater was irradiated with different doses of UV light using a collimated-beam reactor. Dose-response results showed that a UV dose of 15 mW·s/cm2 was enough to inactivate FC to the limit established in Mexican legislation (<1,000 MPN/100 ml) for irrigation reuse, as well as reaching a 2 log inactivation for faecal streptococci. Also, the final concentration reached for Salmonella typhi was <103 MPN, which is the minimal concentration for a disease response in humans. The isolation from the secondary effluent and the pathogenicity determination of Acanthamoeba were carried out. Amoebae were concentrated to higher concentrations than those of the effluent for irradiation tests. Radiation tests showed that amoebae required higher doses than bacteria for their total inactivation (60 mW·s/cm2 for a 2 log reduction). Results showed that UV light is an alternative to inactivate high contents of bacteria and amoebae trophozoites, although higher doses were needed for the high concentrations of amoebae used.
Computer-aided rehabilitation of water networks (CARE-W)
Authors: Sægrov S. , Schilling W. , Røstum J. , Tuhovcak L. , Eisenbeis P. , Herz R. , LeGauffre P. , Melo Baptista J. , Conroy P. , deFederico V. , Mazzacane S. , Schiatti M.
Published: May 2018

The project CARE-W presented in this paper deals with the public water supply networks and their problems of ageing such as structural failures, hydraulic insufficiencies, leakage, deteriorating water quality and increasing maintenance cost that impact on an urban environment. The ultimate goal of the project is to develop a suite of tools, which provide the most cost-efficient system of maintenance and repair of water distribution networks, with the aim to guarantee a security of water supply that meets social, health, economic and environmental requirements. The paper comprises a description of the project work-packages, which include: a control panel of Performance Indicators (PIs) for rehabilitation;a description of technical and statistical tools assessing and forecasting some of the PI;a procedure to define the best choice for annual rehabilitation programming;a procedure to define the best strategy of planning rehabilitation investments (at long term, 10 to 20 years);a software, combining the above products with a common database, tested and evaluated by several test cities.

CARE-W is aimed at utilities for water supply systems, operating companies, local authorities, financial institutions and national regulators. It is supported by the European Commission under the fifth framework programme.
Common utility tunnel for utility services at Putrajaya, new administrative centre of Malaysia
Authors: Adnan S.M. , Heng T.K.
Published: May 2018

With the requirement for utilities to be installed in a protected environment at Putrajaya, the new Administrative Centre for the Federal Government of Malaysia, a common utility tunnel has been developed, designed and is currently under construction. The common utility tunnel (CUT) complements the “No Dig” policy of Putrajaya and offers year-round access for inspection and maintenance of utilities laid inside the tunnel. The design of the CUT incorporates features for phased construction of the CUT and installation of utilities. The utilities to be housed inside the CUT are electrical power cables, water pipe, chilled water pipes, gas pipe, multimedia cables and telecommunication cables. This paper discusses the move behind the implementation of the CUT and describes the planning and design of the CUT. This is the first time that an effort has been made in Malaysia to get all the utility providers to agree to have the various utilities in a common tunnel and also on cost-sharing of the capital and maintenance expenditure.
Whole life costing: application to water distribution network
Authors: Engelhardt M. , Savic D. , Skipworth P. , Cashman A. , Saul A. , Walters G.
Published: May 2018

There is an increasing pressure from the economic regulator in England and Wales for water companies to ensure that their capital maintenance decisions reflect an understanding of the long-term impact on their operational costs and risks. This implies that decisions must not only reflect the costs borne now but the likely costs in the future, and how these might be optimised. It is noteworthy that within the construction and transport industries, asset management decisions which have been driven in this direction utilise a whole life costing (WLC) methodology. This paper addresses the implications of transferring the concept of WLC to service-based assets such as water systems.

A WLC approach to distribution network management aims to achieve the lowest network provision and operating cost when all costs are considered to achieve standards enforced by regulation. Cognisance is to be taken of all relevant costs - direct and indirect, private and societal - in order to balance the needs of the service supplier, the customer, society and the environment in a sustainable manner. A WLC analysis thus attempts to develop a cost profile over the life of the asset. Accounting for the costs over this period is achieved through a combination of activity based costing (ABC) and a life cycle assessment (LCA) used to identify potential social and environmental costs. This process means that each of these identified costs must be linked to some physical parameter that itself varies over time due to changing demands on the system, the different operational strategies available to the operator and natural deterioration of the fabric of the system. The links established between the cost and activities of the operator provide the basis for the development of a WLC decision tool (WiLCO) for application to water distribution network management.