bluuebunny/crossref_metadata_2025 huggingface dataset:
Color removal and disinfection with UV/H2O2 system for wastewater reclamation and reuse
Authors: Ahn K.H. , Park K.Y. , Maeng S.K. , Song K.G. , Kim K.P. , Lee S.H. , Kweon J.H.
Published: May 2018

Reuse of wastewater effluents from secondary treatment processes in municipal wastewater treatment plants has been issued because of substantial volumes of relatively clean waters. The major components of criteria for wastewater reclamations are color, organic matter, and pathogens. An advanced oxidation process with low-pressure ultraviolet and hydrogen peroxide addition (UV/H2O2 system) has been employed for removal of the major components in the criteria for reuse of wastewater. Sand filter pretreatment was applied to remove turbidity and to improve performance of UV irradiation. The results showed that total coliforms were effectively inactivated by the UV irradiation alone with the contact time of 30 minutes but color was remained. The addition of H2O2 significantly improved the removal of color and dissolved organic matter in the same contact time.
Rehabilitation of water networks: analysis of the decision making processes
Authors: Torterotot J.P. , Rebelo M. , Werey C. , Craveiro J.
Published: May 2018

The European Project CARE-W (Computer Aided Rehabilitation of Water Networks), which is supported by the European Commission, has created and tested a prototype of decision support system for the rehabilitation of water pipes. Inside the project, the present operational decision making processes have been analysed in 14 water utilities. The objectives were to identify the involved actors and their interactions, as well as the structure (formal and non formal) of the decision processes: institutional and regulatory contexts, steps of decision making, information fluxes, sharing out of responsibilities and of influence, participation of social and institutional stakeholders. Synthetic results are presented. The cases studied are diversified on several aspects. An “average” situation could be described as showing a moderate level of confrontation, with rather formalised procedures, and very centralised decision making out of the interrelations with road works programming. The highest diversity encountered among the utilities concerns the level of information inside the decision process: data considered, fluxes of information, “sophistication” of criteria taken into account.
Estimate of pipe deterioration and optimal scheduling of rehabilitation
Authors: Kim E.S. , Baek C.W. , Kim J.H.
Published: May 2018

This study proposes an optimal scheduling model for rehabilitation based on the deterioration prediction of existing pipes by using the deterioration survey method for a water distribution system. The deterioration prediction model divides the deterioration degree of each pipe into 5 degrees by using the Probabilistic Neural Networks (PNN). Furthermore, the maximum residual service time is estimated by the calculated deterioration degree for each pipe and pipe diameter. The optimal rehabilitation model by integer programming (IP), based on the shortest path, can calculate the time and cost of maintenance, rehabilitation, and replacement. Consequently, the model proposed by the study can be utilized as a quantitative method for the management of a water distribution system.
Price for water reclamation, how can it be established? A Mexican case study
Authors: Seguí-Amórtegui L. , Alfranca-Burriel O. , Guerrero-García-Rojas H. , Moeller-Chávez G.
Published: May 2018

This study presents the results of an evaluation which provides the necessary decision making tools before to put into operation a System of Reclamation and Reuse Wastewater (SRRWW), in the way to assure the economic viability of the project. This system contributes to improve the sanitary conditions in Jiutepec, Mexico. The applied methodology considers the identification, quantification and economical evaluation of different impacts, private and external, selecting the alternatives that maximize the total benefit. The alternative of the industrial park of CIVAC is the most profitable for the reuse with a maximum benefit of 0.4591 USD/m3. With the idea of recovering all the SRRWW costs, the minimum price of sale of the regenerated water should be 0.2751 USD/m3. Even though all the impacts were not economically evaluated, it does not affect the result on investment decision, since the impacts without evaluating only will increase the benefits of the selected systems.
Modernization of the water utility company of Bogotá (Colombia): an example of public and private participation for solving management problems of water companies in developing countries
Authors: Zuleta F. , Merlano A. , Alvarez A. , Montoya M. , Restrepo E.
Published: May 2018

A common characteristic of water utility and wastewater companies in developing countries is management problems and limited commercial vocation. In the biggest Latin American cities there is a level of infrastructure enough for providing a substantially better service than the one currently supplied to their badly served customers. For years decisions have moved between two extremes: public management – usually corrupted with playing politics and inefficiency problems, and privatization – sharply criticized by many, and which has shown tendencies to inequality that leave it far away from earning panacea status. This paper is intended to expose the advantages of a novel model in which a state-run company with commercial management problems, the EAAB, solves its limitations by keeping the ownership of its assets and successfully incorporating the participation of better practices from other specialized operators, one of which is a state-owned player, EEPPM. This scheme demonstrates how the service indicators of a system serving eight million inhabitants in the Colombian capital improved significantly with state-owned assets and private participation, without giving in to privatization pressures or stagnating in the usual inefficiency typical of public management in developing countries. This is proposed as a replicable experience that can be used in medium and large cities in other countries with similar management problems, with certain adjustments to fit the solution to the specific cases. This is also a practical case for conducting a comparison of competitiveness within a city, of interest for regulatory entities and investigators on the potential of comparative efficiency in a traditionally monopolistic industry.
Removal of micropollutants by NF/RO membranes
Authors: Amy G. , Kim T.-U. , Yoon J. , Bellona C. , Drewes J. , Pellegrino J. , Heberer T.
Published: May 2018

Organic and inorganic micropollutants are rejected by high-pressure membranes, nanofiltration (NF) and reverse osmosis (RO), primarily as a consequence of solute–membrane interactions. These interactions include steric and electrostatic effects that depend on compound properties (e.g., molecular weight (MW) and ionic charge) and membrane properties (e.g., molecular weight cutoff (MWCO) and surface charge (zeta potential)), with the added influence of membrane operating conditions (e.g., recovery). This paper summarizes the rejection trends by several NF and RO membranes for a wide range of organic micropollutants based on hydrophobicity/hydrophilicity (octanol-water partition coefficient, KOW) and charge (neutral or negative), and a more narrow range of inorganic micropollutants in the form of oxyanions (chromate, arsenate and perchlorate) of varying MW and charge. While RO provided greater rejections of micropollutants than NF, observed NF rejections were, in many cases, significant. For oxyanions, rejection was mainly influenced by ionic charge and MW. RO properties generally had little influence while MWCO and zeta potential were both significantly influential for NF. For organic micropollutants, with exception of RO versus NF classifications, membrane properties were less influential than compound properties with greater rejections generally observed with increasing MW, KOW, and (negative) charge.
New directions in water economics, finance and statistics
Authors: Tsagarakis K.P.
Published: May 2018

The IWA conference on water economics, statistics and finance involved multidiscipline participants from academia and industry and decision makers. A number of important issues were considered such as: how utilities are financed, the variety of water tariff structures, measurement of performance and benchmarking, national and regional water industry statistics, water facts, regulation, economic aspects, costs/benefits, feasibility analysis, as well as funding possibilities and practices. This is an overview paper that gives the state of the art on these issues, new directions, which were presented at the conference and the up-to-date literature.
The water demand shaping effects of new irrigation technology: evapotranspiration irrigation controllers in southern California, USA
Authors: Chesnutt T.W.
Published: May 2018

The purpose of this work is a statistical analysis of the net change to water demand among customers who installed evapotranspiration irrigation controllers and customers given irrigation education in the Irvine Ranch Water District, California. This paper documents a statistical analysis of historical water demand to derive estimates of the net water savings from these interventions. This type of empirical investigation is important since California water agencies are considering multimillion dollar investments in this type of demand-side management. Thus, the predictable demand reduction and demand load-shaping are critical to rational economic investment decisions.
Using Bayesian network models to incorporate uncertainty in the economic analysis of pollution abatement measures under the water framework directive
Authors: Barton D.N. , Saloranta T. , Bakken T.H. , Lyche Solheim A. , Moe J. , Selvik J.R. , Vagstad N.
Published: May 2018

The evaluation of water bodies “at risk” of not achieving the Water Framework Directive's (WFD) goal of “good status” begs the question of how big a risk is acceptable before a programme of measures should be implemented. Documentation of expert judgement and statistical uncertainty in pollution budgets and water quality modelling, combined with Monte Carlo simulation and Bayesian belief networks, make it possible to give a probabilistic interpretation of “at risk”. Combined with information on abatement costs, a cost-effective ranking of measures based on expected costs and effect can be undertaken. Combined with economic valuation of water quality, the definition of “disproportionate cost” of abatement measures compared to benefits of achieving “good status” can also be given a probabilistic interpretation. Explicit modelling of uncertainty helps visualize where research and consulting efforts are most critical for reducing uncertainty. Based on data from the Morsa catchment in South-Eastern Norway, this paper discusses the relative merits of using Bayesian belief networks when integrating biophysical modelling results in the benefit-cost analysis of derogations and cost-effectiveness ranking of abatement measures under the WFD.
Cost analysis and evaluation of urban sewage processing units
Authors: Gratziou M. , Ekonomou S. , Tsalkatidou M.
Published: May 2018

This paper provides a comparative evaluation of the total cost for six conventional urban sewage processing units (complete-mix activated sludge, extended aeration and oxidation ditch, with either belt filtration or sludge drying beds for sludge dewatering respectively) as well as for two types of natural processing ones (waste stabilization ponds and horizontal flow subsurface constructed wetlands). This cost analysis emphasizes on cost components, such as construction cost, energy and chemicals costs, maintenance expenses and salaries. Analysis and estimation of cost functions was based on typical Greek cost prices. A percentage analysis of the total cost components is carried out and results for various treatment types are compared. Estimated results are compared to fiscal data collected from units in Greece.
Using water bills to reinforce price signals: evidence from the USA
Authors: Gaudin S.
Published: May 2018

In areas subject to drought and/or high population growth, measures to encourage conservation have become an important part of water management and planning. Residential consumers' low sensitivity to prices reduces the effectiveness and desirability of using price signals as a conservation tool. We hypothesize that consumers' sluggish response to prices is partly due to the fact that price information is not conveniently available to them. If the hypothesis is true, including clear price information on water bills should reinforce consumers' sensitivity to price and therefore increase the power of price-based policies in demand management strategies. A standard aggregate water demand model is augmented with qualitative variables describing the informational content of bills and estimated using a cross section of US utilities. Our results indicate that a utility that spells out unit prices on the water bill can achieve the same level of conservation as others with a thirty to forty percent lower rate increase. We find no evidence that non-price information such as history of use or conservation messages has a significant effect on demand.
Investment strategy for California Water
Authors: McIntyre M.
Published: May 2018

For 150 years California met water needs primarily through expensive surface water reservoirs and increased groundwater pumping. This approach to water management was emulated around the world. Today, however, budget deficits, climate change and competing interest all strain California's ability to meet new needs for a growing population, the economy and the environment. Water for California and the Planning & Conservation League led an effort to assess viable options for California under these new realities. The resulting Investment Strategy for California Water identifies cost-effective, environmentally beneficial and socially acceptable water management strategies for meeting these needs. The Strategy demonstrates how California can more than meet water supply needs with locally planned and implemented programs such as water conservation, recycling and groundwater treatment. As with past California approaches to water management, this Strategy can be useful to other regions facing similar challenges.
Learning from the future: what shifting trends in developed countries may imply for urban water systems in developing countries
Authors: Bengtsson M. , Aramaki T. , Otaki M. , Otaki Y.
Published: May 2018

This study, which is based on reports and articles from various parts of the world, discusses the future development of urban water systems in developing countries. The starting point is the growing need for water and water infrastructure in these countries. Based on an analysis of shifting trends in the water sector in developed countries it is argued that the new infrastructure being constructed runs the risk of soon becoming inefficient and outdated. The first trend is the improvements in domestic water use efficiency; the second is the new sustainability agenda, which places new demands on the water systems. Cities in the developing world have the opportunity to promote domestic efficiency at early stages by laying a strong emphasis on demand management, and to construct more sustainable systems by including sustainability criteria early in the development process.
Technical basis for managing water supply in critical basins: new alternatives applied to the Colombian case
Authors: Escobar J. , Sarmiento A. , Obregón N. , Castillo J.M.
Published: May 2018

In order to advance towards solving the problem of water supply in critical basins in Colombia, the Environmental Ministry and the Javeriana University formulated the technical basis for management of water supply in critical basins. The aim was at developing a methodology that handles in the most efficient way water resources in that kind of system. This guide proposes usage of new technologies for management. Basic geophysical characterization of basins was proposed to be carried out with free GIS software. For water balance, the Thomas model (abcd) was proposed. In addition, it is taken into account the minimum ecological flow rate and the minimum requirements for the control of water quality in the streams. The demand is calculated spatially in order to know how the water resource in basins should be distributed. With the results of water balance and water demand a Decision Support System (DSS) is proposed that joins both the technical results and the expert knowledge of the basin inhabitants. The methodology was applied in critical basins with different conditions and the results show a promising performance of the methodology.
Applicable background minimum night flow for leakage management of small district metered areas in Korea
Authors: Lee H. , Chung S. , Yu M. , Koo J. , Hyun I. , Lee H.
Published: May 2018

In case of Seoul city in Korea, the level of water leakage from any distribution system is evaluated by comparison of measured minimum night flows (NFMs) with a fixed allowable leakage level. However, infrastructure condition of District Metered Areas (DMAs) could be misjudged, because characteristics of the system are not considered properly. Therefore the components of NFM were estimated in residential and business DMAs by using data of night uses collected by modified option A test and real losses from water balance analysis. A new background minimum night flow equation was developed by the components of NFM. Applicability of the equation was tested on various revenue water % residential and business DMAs. As a result, it is concluded that the new background night flow developed in this study is more reasonable in Korea and could be used to judge whether the DMAs have economically recoverable unreported bursts prior to leakage detection activity.
Impact of end uses knowledge in demand strategic planning for Madrid
Authors: Cubillo F.
Published: May 2018

In recent years, there have been substantial changes in the factors that affect a growth in water demand and in the framework and constraints for providing the solutions that will meet these demands. Requirements are growing at the speed of light, whereas solutions are being established at a snail's pace.

In the past, there was considerable headroom where guaranteeing the supply were concerned, but unfortunately the leeway that once existed is being rapidly eroded away. The procedures for facing up to these challenges and new frameworks and problems require new ways of analysis and approach to the solutions. This paper explains the factors that are determinants for the requirements and their solutions, provides figures of reference for the Autonomous Region of Madrid supply system in Spain (5.5 million inhabitants) and the lines that are being followed to reduce the uncertainties involved in demand prediction, so that planning investment in infrastructures can be adapted and water can be managed in a way that is consistent with a set of factors that determine the eventual water consumption as a result of a profound interaction between territorial, social, environmental and economic factors.
The value of data and information for implementing water demand management and the role of the envisaged Rand Water bureau to obtain same
Authors: Buckle J.S. , Leoni T. , Naicker K.M.
Published: May 2018

Successful water demand management requires accurate and timely data about the operation of the system. Various engineering management information systems have been tried in municipalities to capture such data but were prone to become inoperable through neglect. In reaction to this, Rand Water devised a bureau-based service for obtaining water demand management information, with significant benefits to the municipal councils and to the utility.
Sustainable water financing and lean cost approaches as essentials for integrated water resources management and water governance: lessons learnt from the Southern African context
Authors: Hilbig Jens , Rudolph Karl-Ulrich
Published: May 2018

The deterioration of water quality, stressed water resources and increasing water demand are among the most serious concerns in Africa and worldwide. At the same time, there is a lack of efficient and sustainable water management. This is a major challenge for future water governance policies and processes. Economic aspects play a key role for the successful implementation of integrated water resources management (IWRM) measures. Financing mechanisms are of great influence regarding how water and wastewater facilities are designed, built and operated and how these facilities contribute to an efficient long-term management of scarce water resources. Research projects in Southern Africa have shown the need of water management efficiency and the essential role of sustainable water finance for an economically, socially and environmentally sustainable management of these resources.
Control of Toxic Metals at Sewage Treatment Works
Authors: Dakers J L , King R P
Published: May 2018

This paper describes the work done in evaluating the potential improvements that can be made by the application of reasonable trade effluent control to the metals concentration in the sludge at works in the Thames Water Authority.
Sludge Disposal to Sea in U.K.
Authors: Thompson L H
Published: May 2018

A brief review of the extent to which the sea is used for the disposal of sewage sludge in the U.K. is followed by specific references to the activities of each dumping authority and more details of the largest of these operations, by Thames Water, from London. A discussion of the trends and attitudes to sludge dumping at home and abroad stresses the need to retain a proper perspective on dumping in relation to other sludge disposal options and reminds environmentalists that costs cannot be ignored in seeking to minimise effects. The paper concludes with a suggested philosophy on which future sludge disposal decisions might be based.
Sludge Disposal to Sea in South Africa
Authors: Macleod D C
Published: May 2018

The performance of two sea outfalls that have been in operation off the coast of Durban for over 10 years has been monitored for effects on the marine environment and public health. The discharge has been a mixture of domestic sewage and industrial waste from which a large proportion of the sludge has been removed but a 2-year research project, in which the balance of the sludge is also being discharged, has commenced. Performance of the outfalls and details of the monitoring programme are reviewed.
Sludge Disposal to Sea: North American Viewpoint
Authors: Garber W F
Published: May 2018

A review of sludge disposal to sea in North America involves sociological and political as well as technical, scientific or engineering considerations. The review of the interrelationships between these differing types of interests has appeared to be most intense in the United States. Not because of a lesser concern in Canada and Mexico; but because of factors such as the location of most major population centers along the sea coasts, the resulting possibility of environmental problems from waste discharges and the intensity and influence of the environmental movement. From the standpoint of a city or other agency attempting to dispose of solids residual from waste-water treatment in a manner which is both environmentally responsible and economically reasonable, the laws and regulations arising out of the complex of interest cited above pose almost impossible problems. Basic decisions are made by the courts and agency administrators and apply nationwide rather than allowing evaluation of each specific problem. Furthermore, laws applying to air, land and water (sea) pollution conflict so that environmentally responsible solutions become difficult to impossible. Case histories with an outline of the controlling legislation, development of standards and measure of the actual dimensions of such discharge is presented.
Impact of Discharges as a Basis for Control Measures
Authors: Conway R A
Published: May 2018

This paper develops a case for more studies to assess the impact of discharges upon receiving aquatic systems and thereby allow closer tailoring of control measures. General approaches for conducting such studies are described. One approach includes methodology to allow predictions of where in the environment a key effluent constituent will be transported, the rate and extent of its transformation, and its effect on organisms and environmental processes at expected ambient levels.
State-of-the-Art of Modeling Surface Water Impoundments
Authors: Krenkel P A , French R H
Published: May 2018

The state-of-the-art of surface water impoundment modeling is examined from the viewpoints of both hydrodynamics and water quality. In the area of hydrodynamics current one dimensional integral energy and two dimensional models are discussed. In the area of water quality, the formulations used for various parameters are presented with a range of values for the associated rate coefficients.
The Effects of Temperature on the Biochemical Reaction Rates of the Activated Sludge Process
Authors: Randall C W , Benefield L D , Buth D
Published: May 2018

Experimental results and literature information were analyzed to define the effects of temperature change on the fundamental biochemical reactions that take place in the activated sludge wastewater treatment process. The reactions that were investigated were: organic substrate stabilization, production of cellular material, maintenance energy requirements, oxygen utilization, autooxidation of cellular mass and nitrification. Classic kinetic parameters and concepts were used in the analysis of the information. The variation of these parameters with temperature was compared to the variation predicted by the classic Arrhenius relationship for chemical reactions. The results were interpreted in terms of microbial population dynamics in the highly diverse mixed-culture system of activated sludge. It was found that all classically defined parameters follow the Arrhenius relationship over the 5 to 20°C range, but, except for substrate stabilization rate, do not follow it above 25°C.
Surface Chemical Theory as an Aid to Predict the Distribution and the Fate of Trace Constituents and Pollutants in the Aquatic Environment
Authors: Stumm W
Published: May 2018

Surface chemical theory can aid in deriving and quantifying the information needed (equilibrium constants on adsorption, absorption and distribution and kinetic constants related to mass transfer) to predict the distribution, the fate and residence time of trace constituents and pollutants in the environment. Simple surface chemical models for aquatic particulate matter are given in order to illustrate the effect of adsorption onto solid surfaces an an important control on the distribution of trace constituents in natural waters.
The Effect of Submarine Wastewater Discharge on the Bacterial Quality of Surf Waters
Authors: Livingstone D J
Published: May 2018

A system involving enumeration of Escherichia coli I, parasite units, staphylococci and salmonellas, and determination of salinity, was developed for the objective assessment of bacterial water quality in the sea off Durban, South Africa. The system was used to measure the quality of the surf waters before and after the construction of two submarine outfalls. Significant improvement in the quality of the surf along the bathing beaches has been noted since the outfalls became operational.
Baseline Studies and Continuous Monitoring for a Shallow Tropical Bay Receiving Nickel Refinery Effluent
Authors: Carey J E , Pettit M A , Rooney W S , Judell T L
Published: May 2018

Pre-discharge baseline studies and a long-term post discharge surveillance program have been undertaken in order to monitor any effect of nickel refinery effluent on the coastal waters of Halifax Bay, Queensland, Australia. Short-term toxicity studies were conducted as a basis for determining the maximum limit of ammonia, the principal toxicant. Physical and chemical characteristics of seawater and substrates, chlorophyll a concentrations, Zooplankton populations and the benthic invertebrate community have been monitored for eight years. These studies have indicated that the receiving waters, which were initially nitrogen-deficient, have been locally enriched in ammonium-nitrogen. No adverse effects on the marine ecology have been detected. The diversity and abundance of the benthic invertebrates have been maintained. Marginal changes in composition and structure of the benthic invertebrate community, in chlorophyll a concentration and Zooplankton density and biomass, appear unrelated to effluent discharge. It is considered that effective long-term biological monitoring requires a firmer theoretical foundation than is presently offered in the stability-diversity hypothesis and that this can only be attained by wider dissemination of available data.
Chlorine - Resistance of Coliform - Tested Bacteria Isolated from Raw and Treated Sewage Effluents
Authors: Leong L Y C , Otsaka D , Ridgway H F , Olson B H
Published: May 2018

Two hundred and seventy-four bacteria, predominately coliform organisms, isolated from sewage treatment effluents were screened for relative resistance to combined chlorine using a disc assay procedure. Bacteria isolated from tertiary chlorinated effluent were the most resistant to combined chlorine according to the assay procedure. Escherichia coli was the predominate organism isolated from the unchlorinated sewage treatment processes and ranked fifth of 13 genera in resistance to combined chlorine, while Enterobacter sp. was the dominant bacterial genera isolated from chlorinated tertiary effluent and was the most chlorine resistant.
Presence of Phenolic Compounds in Sewage, Effluent and Sludge from Municipal Sewage Treatment Plants
Authors: DeWalle F B , Kalman D A , Dills R , Norman D , Chian E S K , Giabbai M , Ghosal M
Published: May 2018

A total of 25 municipal sewage treatment plants were sampled, 10 of which were resampled, to determine the quantity of phenolics in the sewage, final effluent and the anaerobically digested sludge using capillary GC/MS/DS/techniques. The study noted in decreasing order of frequency in raw sewage: phenol, pentachloro-phenol, dimethyl phenol, 3-methyl, 4-chlorophenol, 2,4,6-trichloro-phenol, 2,4-dichlorophenol, 2-nitrophenol, 2-chlorophenol, 2,4-dinitro-6-methylphenol and 2,4-dinitrophenol. The maximum concentration of phenol in sewage and sludge was 2800 ppb and 4460 respectively, while similar values for pentachlorophenol were 58 and 1200 ppb. Statistically calculated concentration reductions for phenol and dimethyl phenol were generally greater than noted for tri- and pentachlorophenol. Low decreases or increases were noted for monochlorophenol and especially for dichlorophenol as a result of the chloronation of the final effluent.
Ozone as a Sterilising Agent, Its Advantages and Disadvantages in the Treatment of Water
Authors: Schalekamp M
Published: May 2018

Switzerland operates 24 ozone plants per 1 million inhabitants which brings it to first place in the world. Besides Switzerland has 30 years of experience in using ozone in the treatment of spring, ground and surface water. The following points have been proved on the basis of many years of experience and careful testing in the laboratory and plant.

Ozone was initially used mainly as a sterilisation agent, i.e. to kill germs and intestinal bacteria and to inactivate viruses. In the treatment of ground, spring and also surface water, ozone has always worked well. However ozonized surface water which had not been chlorinated showed a tendency to regerminate. Tests and experience have shown that this was partly due to insufficient water treatment. Ozonization also increases the aldehyde and ketone content. They also causes indirect regermination if there follows no GAC-filtration.

To reduce the phenol compounds and the haloforms it is advantageous to add a higher ozone concentration i.e. 1.0 - 1.5 mg O3/litre. This is also the case to improve the colour and the UV-extinction. A higher dosage than normal will, however, have a negative effect on the flocculation and on the regermination if no refiltering with granular activated carbon (GAC) takes place. To destroy bacteria and inactivate viruses as well as for flocculation no higher ozone concentration is required. At a breakdown, however, the possibility to increase the dosage above normal would be important. Therefore, a plant should always be designed to enable the dosage of higher ozone concentration by reducing its capacity. When installing an ozone plant it must never be forgotten that it has to be continually monitored with special emphasis on the ozone concentration in the water. If you operate ozone plants you will also have ozone in the exhaust air. This ozone causes difficulties and must be eliminated. By larger plants you can do the ozone destruction best with a thermic/catalytic system. In order to assure the proper functioning of the ozone destruction facility, a continous monitoring is indispensable. For safety reasons not only the exhaust air but also the plant air must at all times be continually monitored.
Removal of Potential Carcinogens and Toxicants by Treatment Systems for Direct and Indirect Reuse of Wastewater Evaluated by Means of a Hamster Cell Culture Assay
Authors: Kfir R , Prozesky O W
Published: May 2018

Removal of potential carcinogens and toxicants by a direct wastewater reclamation system and an indirect wastewater reuse system was evaluated by means of a sensitive golden hamster cell transformation assay. Representative water samples from various stages of both the direct and the indirect reuse systems were introduced to the hamster cells and changes in the rate and pattern of cell growth were observed. Both systems proved to be highly effective in their removal of potential carcinogens and toxicants and there is no indication that the slight toxic and transforming activity detected in their final water may constitute a health hazard.
Desalination by Continuous Ion Exchange Based on Thermally Regenerable Magnetic Microresins
Authors: Bolto B A , Swinton E A , Nadebaum P R , Murtagh R W
Published: May 2018

The removal of small quantities of salt at the 500 to 2000 mg/L level is becoming increasingly necessary to counter one of the most widespread forms of water pollution encountered throughout the world. Ion-exchange resins which can be regenerated with hot water have been used previously in a batch mode for the desalting of both natural waters, and municipal and industrial wastewaters. Continuous operation would offer many advantages, especially for productivity, heat economy and ease of control. Unfortunately existing continuous ion-exchange contactors are intermittent in operation and somewhat complex.

This paper describes the unique hydrodynamic and kinetic properties of “Sirotherm” thermally regenerable desalting resins when made in the form of magnetic microbeads, and the development of continuous contacting systems which exploit these properties. A novel multistage contactor has been evaluated on laboratory and pilot-plant scales. A prototype plant, with a throughput of 1 ML/day, is to be installed near Perth, Western Australia, in order to demonstrate the process. It is truly continuous, simple and economic, and does not require preclarification of the raw water.
Mass-Transfer Characteristics within Microbial Systems
Authors: Onuma M , Omura T
Published: May 2018

The diffusion coefficient within a microbial system was determined by both diffusion and kinetic studies on the basis of Fick's model and an effectiveness factor model, in order to predict the mass-transfer characteristics of this system. It was found to be dependent on the molar weight and C/N ratio of the compounds and substrates used in the diffusion study. On the otherhand, the transitional film thickness from a reaction limited case to a diffusion limited one was found to be about 150 µ in a kinetic study. The observed diffusion coefficient in the diffusion study was of the same order as that of the kinetic study.
The Fate of Some Metal Species: Lead, Cadmium, Zinc in Surface Water, during Biological Sand Filtration – Effect of Preozonation
Authors: Erb F , Delabre D , L'Hopitault J C , Philippo A , Thomas P , Brice A
Published: May 2018

This study was performed to determine the elimination of the different chemical species of some toxic metals - zinc, lead, cadmium - during biological sand filtration on surface water containing humic material which is able to promote the complexation of metals. The effect of preozonation was examined.

The metal speciation was realised by means of Atomic Absorption Spectrometry and Differential Pulse Anodic Stripping Voltammetry. The survey of organic matters was carried out by measuring TOC, UV absorption and fluorescence.

The biological treatment of raw water is quite effective for the removal of particu-late metals. The data bring out an important decrease for dissolved metals - about 50 to 60 % with cadmium and lead - especially noteworthy for the labile complexed metals.

The preozonation of raw water provides the redissolution of particulate cadmium and zinc which are converted to free metals and seem then to be more eliminated by biological filtration.

Ozonation appears to improve the efficiency of biological treatment which usually gives higher yields of purification than floculation (aluminium sulfate) in the same conditions.
The use of Mathematical Models in the Formulation of Pollution Control Policies – An Overview
Authors: Gerber A
Published: May 2018

The principles underlying the development of mathematical models are outlined in non-mathematical terms. Some of the advantages and limitations of computer models are highlighted, especially ways in which models may be misused. The skills required for effective modelling are sketched as are major problem areas hampering the general application of models.
Application to Rivers and Underground Waters
Authors: Marivoet J. L. , De Smedt F. , Van der Beken A. , Dirickx J. , Van Craenenbroeck W.
Published: May 2018

Mathematical models describing the water quality in rivers and groundwaters are derived from the mass balances.

For rivers, a one dimensional transport equation is derived. Different methods of parameter estimation are considered and more recent techniques are introduced.

For the application of water quality models to river management, two groups of models are considered : the simulation models and the optimization models. As a case study, the Bedford Ouse quality models are described. Practical and theoretical applications in the United Kingdom, Canada, Federal Republic of Germany, U.S.A. and Belgium are discussed.

For groundwaters, several applications of water quality transport models are discussed and the use in groundwater management is explained.
Legal and Administrative Control Aspects of Oil Pollution
Authors: Read A D
Published: May 2018

The nature of the releases of oil to marine and fresh water environments that can occur during the production, transportation and refining of crude oil and from the distribution, use and ultimate disposal of its products are considered. The development of the national and international regulations aimed at minimising pollution from these various activities is discussed, as are the arrangements for dealing with major releases of oil and for providing compensation for those incurring expenses or losses from such incidents.
Selection of Practical Indicator Systems for Monitoring the Virological Quality of Potable Water, Wastewater, Solid Waste, Shellfish, Fish and Crops
Authors: Scarpino Pasquale V
Published: May 2018

The actual detection of viruses or the use of an indicator system or systems to assess the presence of pathogenic viruses in contaminated environments is essential for the protection of human health. Herein are considered the possible surrogate relationships between pathogenic viruses and bacterial indicators of fecal pollution in the diverse enviroments of potable water, wastewater, solid waste, shellfish, fish and crops. Assessments are made concerning the reliability of the indicator to identify in these diverse environments viral presence. It is concluded that thus far no one has demonstrated a convincing relationship between the numbers and/or types of different indicator bacteria and the pathogenic viruses themselves, and that the best indicator of viral presence is the actual detection of the virus itself. Nevertheless, the search should continue for more acceptable alternatives which would eliminate the need for the more difficult and time consuming direct testing of pathogenic virus presence.
Developments in Methods for the Detection of Viruses in Large Volumes of Water
Authors: Guttman-Bass Naomi
Published: May 2018

The purpose of this review is to summarize recent developments in virus concentration methodology. Evaluations of virus recovery by electronegative and electropositive membrane filters, as well as other methods of virus concentration reported in recent literature are discussed.
Human Enteric Viruses Isolated from Influents of Sewage Treatment Plants in S. Paulo, Brazil
Authors: Martins Maria Therezinha , Soares Laurinda A , Marques Elizabeth , Molina Antonia G
Published: May 2018

In order to isolate human enteric viruses from sewage, a study has been undertaken in Brazil. From 55 sewage samples, 433 virus strains have been isolated. These comprised 70.7% poliovirus, 19.2% echovirus and 7.6% coxsackievirus, 2.5% remained untyped. Five different methods were used for virus recovery: adsorption to and elution from membrane filters; acidic precipitation; concentration through membrane filters, with reconcentration by organic flocculation; concentration on aluminum hydroxide; aluminum sulfate precipitation.

The sewage sample were plaqued in bottle cultures BS-C-1 cell line. This cell line allowed a recovery of 22 different serotypes of enteroviruses: the three poliovirus types, 14 types of echoviruses, four types of coxsackie B virus and one type of coxsackie A virus.
Zero Liquid Discharge Control in United States Coal Fired Steam Electric Stations
Authors: Heimbigner Brian E
Published: May 2018

The requirements for zero liquid discharge in the United States originated in 1972 when the United States Congress enacted broad amendments to the Federal Water Pollution Control Act. This legislation, along with various other state and regional regulations, has required many electric utilities to commit to zero liquid discharge prior to being issued a construction permit. This is particularly so in the water scarce Southwestern region of the United States.

Since the enactment of pollution control legislation, twenty-four coal fired power stations coming on-line were required to achieve zero discharge. The stations have chosen equally between evaporation ponds and mechanical recovery methods as the solution. A review of the factors affecting the choice and design of zero discharge systems is presented. Methods to improve the overall plant water balance by a total water system design, during the plant design phase, is also discussed.
On the Definition of a Mixing Zone
Authors: Nielsen Tue Kell , Rasmussen Jørn
Published: May 2018

A mixing zone is a common administrative tool for illustrating impacts of a thermal discharge. Depending on its definition, a mixing zone may demonstrate either the initial dilution of the cooling water, or it may give some idea of an area, where certain environmental consequences are to be expected. Also, a mixing zone may form the basis for a control programme.

A clear and simple definition of a mixing zone should state 1) a time scale (e.g. instantaneous values), 2) a location (e.g. a section across a river), 3) a water depth (e.g. the surface), 4) a measure of impact (e.g. a temperature difference relative to the intake temperature), 5) a unique decision rule (e.g. the measure should be less than a given value).

When good knowledge is available about hydrographical and biological circumstances, and environmental consequences of small temperature increases, approval and control of a thermal discharge may well be based directly on the magnitude of the discharge, instead of introducing a mixing zone.
Near Field and Far Field Evaluations of Excess Temperatures Due to the Discharge of Cooling Water in Stratified Coastal Water
Authors: Sørås Per Erik , Thendrup Arve , Tryggestad Svein
Published: May 2018

The cooling water discharge from the gas terminal at Kårstø in Norway will be in the order of 7 m3/s and heated about 10°C. The cooling water will be withdrawn through an intake structure at 25 m depth and discharged at 10 m depth. The intake structure and the intake depth were chosen in order to prevent recycling of cooling water, to withdraw water with a stable and low temperature and to prevent fouling in the heat exchangers. The analyzing methods and results will be presented.

The outlet area consists of several small islands, sounds and fjords. Salinity and temperature were measured to determine the stratification. In order to calculate the volume exchange and hence the excess temperatures in the outlet area, a great number of current measurements with continously recording instruments were performed. Tracer measurements and drift card investigation were also performed in order to evaluate the transport and dilution of the cooling water discharge.
Water Pollution Arising from Solid Waste (Coal, Fly Ash, Slag) Disposal, and Measures to Prevent Water Pollution
Authors: Golden Dean M
Published: May 2018

This paper reviews the pathways that large volume utility wastes can take which can cause environmental effects. Potential interactions of the environment with land-disposed utility wastes include: (1) effects on local air quality, (2) efforts on soils and vegetation, (3) phytotoxicity, (4) groundwater effeccts, (5) effects on surface waters, and (6) disposal site washout. Both natural and engineered mitigating mechanisms are reviewed.
Ocean Disposal of Consolidated Spray Dryer Flue Gas Desulfurization Wastes
Authors: Donnelly J R , Webster W C , Duedall I W , Hsu K J , Parker J H , Woodhead P M J
Published: May 2018

Combustion of coal in electric power generating stations results in the production of large quantities of fly ash and flue gas desulfurization end products. These wastes must be disposed of by environmentally acceptable means. Ocean disposal of these wastes is an attractive option for power stations located on coastal waterways. Dumping of fly ash and untreated wet FGD sludge is environmentally deleterious. However, wet scrubber sludge stabilized with fly ash can be formed into solid dense blocks which have been shown to be acceptable for ocean disposal. The Marine Sciences Research Center has been investigating this disposal option for the past five years.

A new FGD technology, Spray Drying Absorption, was introduced about five years ago. This process produces a dry end product composed of fly ash, desulfurization reaction products and excess reagents. When lime is the reagent the end products can be dampened and consolidated into self-hardening dense blocks. Niro Atomizer has been investigating dry FGD end product disposal and utilization for the past three years.

An assessment of the feasibility of using solid blocks formed from dry FGD end products for ocean reef construction is being performed by the Marine Sciences Research Center. Consolidated dry FGD end products from Niro Atomizer's Riverside dry FGD demonstration facility and Copenhagen dry FGD pilot plants were tested. These wastes represent low sulfur western and European coal applications. The end products were dampened and consolidated into Proctor cylinders. After curing, the cylinders were exposed in sea water systems including the open seas for up to 6 months. Block structural integrity was maintained during this period and porosity remained essentually unchanged. The unconf ined compressive strength remained high during the test period.