bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluation program as a driving force for efficient operation and maintenance of waterworks
Authors: Choi Suing-il , Yoon J.Y. , Hong S.K.
Published: May 2018

One of the practical means for waterworks to compete with each other for efficient operation is implementing an evaluation program. The evaluation program, coinciding with public notification, was prepared and implemented as a trial in Korea in 2003. However, several unexpected issues arose during the implementation. The evaluation scheme has been revised and described in this paper. The water quality might better be used as a qualification barrier for the further evaluation process. It may also be reasonable to consider that the evaluation team might visit on a very exceptional day for the plant, therefore it might be better to let the evaluation team have enough time to assess plants more extensively. The collateral case study reports should be used as a manual to maintain consistency between the evaluation teams. Although the case study took place in Korea, the revised principles from this experience may be beneficial to other countries.
Identification of key local factors influencing revenue water ratio of Korean cities using principal component analysis and clustering analysis
Authors: Chung S. , Lee H. , Yu M. , Koo J. , Hyun I. , Lee H.
Published: May 2018

In order to identify the relation between revenue water (RW) ratio and key local factors in a quantifiable way, 90 effect factors were considered as regional characteristics for 79 Korean cities. Seven statistically significant effect factors were chosen through correlation analysis. Three principal components independently influencing RW ratio were extracted by principal component analysis (PCA). The 79 cities were grouped into six clusters by k-means clustering (KMC) of the factor scores of the cities. Then key local factors were identified and their impacts were quantified by multiple regression analysis (MRA) and they were justified by T-test and F-test. The approach through correlation-PCA-KMC-MRA was proved to be one of scientific ways for identification of key local factors. According to the result, it was suggested that a shorter length of distribution system, a water supply with smaller number of bigger customer meters a and gravitational supply through reservoir would be advantageous from a RW ratio's point of view.
Needs and barriers in technical regulations and standards for the efficient use of water: situation in Portugal and Brazil
Authors: Almeida M. do C. , Vieira P. , Ribeiro R. , Andrade M.
Published: May 2018

Appropriate legislation, technical regulations and standards are essential to put into practice water-efficient technologies, procedures and products, both to promote the implementation and to avoid eventual barriers in the application of the adequate measures. In Portugal as in Brazil, efficient use of water and the reduction of water waste are important environmental goals. In the former, the National Program for the Efficient Use of Water for the urban, agricultural and industrial sectors is the base document for this purpose. In the latter, the National Program to Prevent the Waste of Water, for the urban sector, has been in action since 1997.

The purpose of the paper is to present a brief overview of the current situation in terms of regulations and standards, highlighting the needs and some barriers, having as reference the situation in Portugal and Brazil, and the measures intended to be applied in the respective programs.
The Canberra least cost planning case study
Authors: Turner A. , White S. , Bickford G.
Published: May 2018

This paper provides details of a preliminary least cost planning (LCP) assessment carried out for Canberra, the capital city of Australia, as part of the development of a 50 year Water Resources Strategy. In the assessment a suite of options consisting of demand management, source substitution, reuse and supply were developed to determine how to satisfy water demand requirements for the projected population over the 50 year planning horizon whilst also achieving the identified demand reduction targets. The options developed were then compared on an equal basis using the principles of LCP to identify the suite of lowest cost options to be considered for further analysis and implementation. The suite of demand management options developed was found to have the lowest whole of society levelised cost. Since the preliminary analysis and release of the Water Resources Strategy in April 2004, a water efficiency team has been set up to develop an implementation plan, implement options, develop an end use model, conduct pilot studies and undertake program evaluations.
A phased approach to efficiency improvement in low-income countries: the case of the National Water and Sewerage Corporation in Fort Portal town, Uganda
Authors: Mutikanga H. , Mugisha S.
Published: May 2018

Most water and sewerage utilities are faced with the challenges of improving efficiency and will pass on gains to their customers. The challenges are more in low-income countries especially those in Africa. There has been a lot of on-going debate and studies about approaches and options to water utility efficiency improvement in these countries to meet the Millennium Development Goals (MGDs). About ten years ago the emphasis was on private sector participation (PSP). Consequently, most development partners propagated this approach and even went to the extent of conditioning PSP implementation to funding. The option delivered varied degrees of successes contingent on the operating contexts in those countries. Attempts to mitigate the wrong contexts and conditions to suit the PSP have proved to be more expensive than potential benefits from the option itself. As a result, many low-income countries have been compelled to be more innovative and widen the scope of solution search. The debate currently is, therefore, about performance improvement other than PSP options. This paper presents a phased approach to efficiency improvement taken by National Water and Sewerage Corporation (NWSC) of Uganda in the last seven years. We discuss mechanisms that NWSC has used to achieve significant efficiency gains. Managerial incentives and autonomy are at the centre of the successes registered. We also draw conclusions on how private management principles can be introduced into the public sector to improve efficiency.
Ocean Disposal Legislation in the United States†
Authors: Guarino C F , Townsend S
Published: May 2018

A review of legislation and implementing regulations pertaining to disposal of sludge at sea in the United States was performed. The experiences under the law of two major municipalities that have employed diposal at sea were studied and compared.

Major changes are shown to have taken place in the Federal approach to regulating ocean disposal. Ocean dumping regulations are shown to have produced very different current situations for two major municipalities. The City of Philadelphia, operating under rigid federal policies, successfully ended ocean disposal over a year before the statutory deadline by implementing carefully managed, but costly, land-based sludge disposal alternatives. The City of New York, in contrast, still uses the ocean for sludge disposal and has recently won a ruling in Federal District Court which may allow continued ocean disposal for many years beyond the December 31, 1981 end-date proscribed by the law.

†This paper should be included in Theme 1A - Legislation.
Sludge Disposal to Sea in France†
Authors: Aubert M , Gauthier M J , Aubert J
Published: May 2018

After a general review on the nature of the polluting elements in domestic sewages and on the relationships between bacteria and particulates in sludges, a mathematical formulation of the dynamics of suspended matter in the sea is presented. On the basis of these data, the different types of treatment of wastewaters and sludges used in France are described and discussed.

†This paper should be included in Theme 3 - Case Histories.
Biological Nitrification in an Up Flow Fixed Bed Reactor (UFBR)
Authors: Faup G-M , Leprince A , Pannier M
Published: May 2018

This paper describes a kinetic model for ammonification and nitrification in an upflow fixed bed reactor (UFBR) with direct injection of air into the support material. Modeling has been based on the computation of active biomass concentration along the reactor. The tests, which extended over a period of one year and have been applied to municipal sewage after conventional treatment using activated sludge, have shown that the filtration rate is the most important factor as regards both the overall quantity of biomass found in the system and the distribution of this biomass within the reactor. The optimum quantity of biomass is obtained with a filtration rate of around 5 m3.m2.hr. Under these conditions, it is then possible to reach active biomass concentrations 8 to 9 times higher than the ones found in conventional processes based on the use of nitrifying activated sludge.

It is also clearly evidenced that ammonification will, in most cases, be incomplete and this will limit the efficiency of the overall reaction Total N → NO3−.

Other parameters also greatly influence the process : among these parameters, the influence of the ratio air process rate/influent rate has been the subject of special examination.
Simulation of Nitrification and Its Dynamics in a Rotating Biological Contactor
Authors: Watanabe Y , Bravo H E , Nishidome K
Published: May 2018

Nitrification in a partially submerged rotating biological contactor was analyzed by computer simulation. Results of the simulation showed that the ammonia flux to the biofilm is a function of its spatial position as it rotates alternately in air and liquid phases. However, the simulation and the steady-state model proposed by the authors gave almost similar results in terms of the average ammonia flux to the biofilm. The latter provides the basis behind the application of the steady-state biofilm kinetics to the nitrification process in a partially submerged rotating biological contactor. Then steady-state kinetics was applied to the analysis of the nitrification process in the dynamic state. A pseudo-steady-state approach was verified using the pulse and step forcing functions.
Re-Use of Sludges and Treated Waste Water in Agriculture (Troubles Arising from the Contamination of Soils with Heavy Metals and from Application of Sludges and Treated Waste Water in Agriculture)
Authors: Kloke A
Published: May 2018

It is the task of agriculture to produce foodstuffs which in amount and quality fit the demands of the consumers and legislation. It can, however, meet these demands only if the offered aids of production, in this special case the sewage sludge, do not bring along a threatening accumulation of heavy metals in soil and plants. As plants take up and accumulate increasing amounts of heavy metals with increasing amounts of these hazardous elements in the soil, it was necessary to establish tolerable amounts of heavy metals in soil. They are meant as a precaution, for air and water can be cleaned or are cleaned on their own. Soil, however, once contaminated with heavy metals, according to our present day technology and knowledge, can not be cleaned.
Some Perspectives in the Modelling of Biological Treatment of Wastewaters
Authors: James A
Published: May 2018

This paper reviews some recent developments in the modelling of the biological treatment of wastewaters with particular reference to the activated sludge process. The bacterial kinetics of completely-mixed reactors are discussed emphasising the need to have a variable yield. Modelling complications of variable yields are noted in particular those caused by de-coupling growth and substrate utilization. Other methods of solution are considered including relating the yield to the sludge age.

Modelling developments in fixed-film reactors are briefly examined, comparing the refinement in the chemical/physical description with the lack of refinement in the ecological representation.

The aims of modelling are reviewed and some fruitful areas in operational models and computer-aided-design are identified.
Studies on Oxygen Transfer Models
Authors: Matsuo T , Hirayama K
Published: May 2018

The liquid film coefficient of the oxygen transfer at air-water surfaces is dependent on turbulence characteristics of the flow. There are two methods for evaluating the liquid film coefficient with relation to turbulence; One is based on the root mean square velocity fluctuation and the larger scale movement and the other is based on the energy dissipation rate and the smaller scale movement.

Conclusions obtained from some experimental and dimensional analyses imply that, for the mass transfer mechanism at the air-water surfaces, larger scale turbulent motion is dominated over smaller scale eddies represented by Kolmogoroff's micro-scale.
Land Extensive Processes for Wastewater Treatment and Disposal – A Perspective
Authors: Parker C D
Published: May 2018

Land extensive processes for treatment of wastewater have been used for pollution control for over a hundred years.

Recently more sophisticated demands related to protection of the environment, energy considerations, and costs related to conventional biological and physico-chemical processes, have been responsible for great scientific endeavour in the understanding, assessment of purification mechanisms, behaviour and performance, and the costs, of land extensive systems of treatment by lagoons and by land irrigation.

Favourable characteristics of these land extensive processes have led to their widespread application in suitable sparsely populated areas particularly in developing countries.

The paper details the processes, the factors which should influence their proper design and performance, and assesses their favourable and unfavourable characteristics.

Guidelines for the determination of their feasibility in a particular situation are given.
High-Rate Algae Ponds for Wastewater Treatment and Protein Production
Authors: Shelef G
Published: May 2018

High-rate algal ponds (HRAP) under proper climatic conditions can produce annually over 150 tonnes of dry biomass per hectare of which 60 percent is photoautotrophic algae. This result in production of approximately 150 ton/ha-yr of oxygen, in addition 15 ton/ha-yr of nitrogen and 3 ton/ha-hr of phosphorus are removed by incorporation into the biomass which contain between 45 to 50 percent proteins. High quality effluent is produced following physico-chemical separation of the suspended biomass by alum flocculation and flotation.
Influence of Discharges from Storage Reservoirs on the Tastes and Odours Appearing in the Seine and Marne Rivers
Authors: Rizet M , Mouchet J
Published: May 2018

This study was conducted in order to understand the taste and odour problems that occurred in the Seine and the Marne rivers during the severe drought of 1976.

Samples were taken every 15 days from several locations in the rivers themselves and from storage reservoirs upstream from Paris.

Algae and actinomycetes were identified and counted. Metabolite concentrations were measured. These data were correlated with threshold odor numbers and bacteriological water quality parameters.
Depositional Process of Fine Sediments
Authors: Kusuda T , Umita T , Koga K , Yorozu H , Awaya Y
Published: May 2018

The main purposes of this study were to investigate the depositional properties of the typical fine less-cohesive sediments in Japanese estuaries and bays and to make it possible to estimate the amount of deposition of the sediments. Suspended fine sediment concentration depends strongly on the shear stress and a critical particle diameter exists corresponding to a certain shear stress. The suspended particles larger than the critical diameter settle down proportionally to the concentration of particles. On the other hand, the suspended particles smaller than the critical diameter are held in water without settling. The depositional properties obtained from experiments make it possible to estimate the depositional rate and amount of the sediments. In the laboratory experiments on deposition, an annular flume with a ring and a channel was used.
Nutrients and Algal Growth in an Impounded River, Consequences for its Oxygen Balance and Nutrient Control Strategy
Authors: Imhoff K R , Albrecht D R
Published: May 2018

A series of impoundments occur on the final 46 km stretch of the Ruhr river where phosphorus, nitrogen, and organic carbon are present abundantly, causing several heavy algal blooms during the year. This is detrimental for the treatment capacity of the water works. Also, an oxygen shortage is always recorded in the river after algal decay at low flows, thus requiring artificial aeration. By balancing all oxygen supply and consumption it is shown that about 2/3 of the oxygen demand is due to algal decomposition. When evaluating the water quality data of the past 30 years and by conducting special laboratory tests, results show that phosphates initiate algal growth. Therefore, a phosphate model has been developed for the river which predicts the phosphate content for 1988 and 1998. It is expected that by reduction of this phosphate content maximum algal growth can be cut by about 50 %.
Fractional Composition of Phosphorus Forms in Sediments Related to Release
Authors: Furumai H , Ohgaki S
Published: May 2018

The relation between the fractional composition of phosphorus forms in sediment and phosphorus release was investigated experimentally using incubation bottles. The validity of the sediment phsophorus fractionation method developed in the field of soil science was examined and it proved to be successful for fractionation of pure phosphate compounds which were added to sediments. The iron and aluminum phosphate and adsorbed phosphorus were recovered in NaOH (lN) extractable ortho-phosphate (NaOH-o-P) fraction, calcium phosphate in HC1 (lN) extractable ortho-phosphate (HCl-o-P) fraction, and organic phosphorus in MaOH extractable total-phosphorus except for ortho-phosphate (NaOH-[T-o]-P) fraction and residual (Res.-P) fraction. This method was used to identify the form of phosphorus in sediments collected from a lake and a canal. NaOH-o-P fraction was the main phosphorus constituent in both sediments.

The change in MaOH-o-P fraction accounted for most of the change in total sediment phosphorus. NaOH-o-P fraction in the sediment decreased during the period of incubation as the concentrations in the water increased but other fractions remained constant. The addition of iron phosphate and adsorbed phosphorus to the sediments promoted phosphorus release. Therefore, the changes in the fractional composition of the phosphorus forms indicated that NaOH-o-P fraction is the form of phosphorus which is most easily released under anaerobic condition. The amount of this fraction is the index of the phosphorus release potential of sediments.
River-Basin Planning for Control of Nitrate Pollution
Authors: Sinnott C S , Jamieson D G
Published: May 2018

The combination of increasing nitrate concentrations in the River Thames and the recent EEC Directive on the acceptable level in potable water is posing a potential problem. In assessing the impact of nitrates on water-resource systems, extensive use has been made of time-series analysis and simulation. These techniques are being used to define the optimal mix of alternatives for overcoming the problem on a regional basis.
Enterovirus Concentration Using Automated Hollow Fiber Ultrafiltration
Authors: Belfort G , Paluszek A , Sturman L S
Published: May 2018

The Automated Hollow Fiber Ultrafiltration (AHFU) method is proposed here as a simple, efficient and rapid virus concentration technique from tap and drinking water sources.

The results reported here extend the testing of the AHFU method to include two Picornaviruses [Poliovirus 2 (vaccine) and Echovirus 1] and Reovirus 3. Their respective mean virus recoveries from between 3 and 100 l of tap water is 88 ± 26, 79 ± 60, and 104 ± 48%.

Various approaches including membrane surface modification, changes in backwash hydrodynamics, modification of the feed and backwash composition, and the use of S35-methionine labelled Poliovirus 2, are used to study the recovery of sorbed Poliovirus 2 from the hollow fiber/solution interface. An increase in the backwash pH to between 9.5 and 10.5 significantly improved Poliovirus 2 recovery. This, together with the labelled experiments, indicates that the virus-membrane interactions are probably electrostatic in nature. Convective polarization during filtration probably brings the virus close enough to the surface for these interactions to occur since virus losses were not detected for a non-permeation recycle experiment.

Because very low Reynold's numbers are used, the flow is in the creeping-flow-regime for both filtration and backwashing (axial and radial). Unless significantly higher Reynolds could be used, enhanced recovery due to purely hydrodynamic forces is unlikely. High Reynold's numbers, of course, are limited by the pressure constraints of the hollow fibers.
A New Large Scale Technic for Quantitative Recovery of Enteroviruses by Adsorption on Suspended Glass Powder. Application to Surface and Drinking Waters of the Paris Area
Authors: Vilaginès Ph , Sarrette B , Danglot C , Vilaginès R
Published: May 2018

The aim of this work is to describe a new and inexpensive glass powder apparatus allowing virus concentration from 500 1 sample of water (10). Its efficiency was determined by analysis of drinking and surface waters preinoculated by Poliovirus. The detection of viruses from river water is compared when 500 1 (new apparatus) or 10 1 (preceeding apparatus) (7) are processed. The proposed new 500 1 apparatus allowed the recuperation of viruses in 100 % of the analysed samples the 10 1 one allowing their recuperation in only 50 % samples. This method was applied to the virus determination in the surface and drinking waters of the Paris area.
The Economic Impact on an Urban and Industrial Complex of Mineral Pollution in the Water Supply – A Case Study
Authors: Heynike J J C , McCulloch S F
Published: May 2018

The only water source available to the most dense urban industrial and mining territory in the Republic of South Africa is subjected to increasing mineral pollution. Investigations of the causes and effects are referred to as well as to the mathematical modelling of the water system that could lead to improved water quality.

The economic effects and costs to the Community as a whole are described and quantified.
Application of the Marais - Ekama Activated Sludge Model to Large Plants
Authors: Nicholls H A
Published: May 2018

The Marais-Ekama model was used to successfully predict the performance of two 50 000 m3/d five-stage nutrient removing activated sludge plants. The experimental data used to test the model was obtained by monitoring the feed, effluent and contents of each reactor in the process, every two hours for 4 days. In addition, a respirometer was developed to measure the oxygen utilisation rate automatically every 30 minutes. All data collected was found to be valid, as acceptable COD and nitrogen balances across the plants were possible. The data was then compared with the steady state and unsteady state responses of the model.

It was found that the model could successfully predict the COD, TKN, Ammonia and nitrate concentrations in the effluent and illustrate some shortcomings in the process layouts. This indicated that the model could be used by designers and operators of large-scale plants to predict performance and highlight problem areas.
An Integrated Low Cost System for Treatment of Potato Processing Wastewater Incorporating Anaerobic Fermentation and Phosphorus Removal
Authors: Parker J G , Lyons B J , Parker C D
Published: May 2018

The pollution load from a modern potato processing plant represents a substantial wastewater treatment and disposal problem with considerable potential for process innovation. With continued increase in energy costs, recent developments in treatment of industrial organic wastes by direct anaerobic fermentation rather than conventional energy intensive aerobic processes, offer considerable cost savings for wastewater treatment in the potato and other food processing industries.

The development, through pilot plant investigations, of a low cost, integrated system incorporating anaerobic fermentation and phosphorus removal facilities is described. Details of full scale plant design, performance and costs, including aspects of utilization of treatment plant by-product biogas, and land disposal of residual phosphorus sludge as low grade fertilizer, are presented.

Operating data obtained since commissioning of the full scale plant in January, 1980 demonstrates consistent achievement of an overall B.O.D.5 removal efficiency of 90% and an overall phosphorus removal efficiency of 93%. Total annual treatment cost is $A0.15/kg B0D5 removed (1981 costs).
Aerobic Thermophilic Stabilization of Sludge versus Anaerobic Digestion and Other Kinds of Sludge Treatment at Middle-Sized Plants with Respect to Power Conservation and Economy
Authors: Wolf P
Published: May 2018

Operating data concerning energy balances are collected by a state bureau from a sewage treatment plant with aerobic–thermophilic stabilization and also from plants with anaerobic sludge digestion and energy recovery. On the basis of this data power and heat balances as well as cost–benefit–calculations have been obtaineu for treatment plants of different sizes with different biological and sludge treatment processes. In spite of high and rising energy costs in plants utilizing the aerobic-thermophilic stabilization process the results show an overall economic benefit for this process at small and middle-sized treatment plants compared to those utilizing anaerobic sludge digestion. The evaluation of data indicates that this economic benefit is due to high capital costs and little efficiency of energy recovery under process conditions at small and middle-sized plants applying anaerobic digestion.
Simultaneous Pasteurization – Digestion (SPD-Process)
Authors: Kugel G
Published: May 2018

As part of the regional sludge disposal system of recycling to land, which is integrated into the Niers river basin management of the Niersverband, FRG, pasteurization is done in combination with the anaerobical stabilisation of sludge in order to ensure a long-term agricultural disposal with respect to hygienic hazards which is in general much less expensive than any other alternative sludge handling and disposal.

During the past 15 years of Niersverband activity in liquid sludge recycling pasteurization has been done after digestion, mostly by flash heating along the CANZLER process with steam. Alternative heating by submerged combustion here has been proved reliable after nearly 10 years experience of several installations of this kind for raw sludge pasteurization with oil fuel supply.

Submerged combustion heating with digestion gas supply has been running at a medium sized sewage treatment plant (100.000 population equivalents) during the past two years. The pasteurization, which was first done after digestion, was now successfully put in front of the anaerobical stabilisation with sufficient gas yield, organic matter degradation, and stable low concentration of organic acids (CH3 COOH) in the digester at a positive gas energy balance.
Role of Equipment Suppliers
Authors: Bernard J
Published: May 2018

Equipment represents one of the essential elements in the transfer of technology. The need for new equipment may have many different origins of technical, social or economical nature. The exchange of knowledge between searchers, designers, manufacturers and users is not equally easy in all cases but, in a free competition economy, the information is diffused very rapidly.

Depending on the countries and the final owners and users of works, the extent of technical knowledge and of the responsibilities demanded from equipment suppliers may be highly different and this influences the efficiency and rapidity of the transfer of technology.
Legal and Administrative Aspects
Authors: Brynolf L , Hawerman B
Published: May 2018

In most developing countries the legal and administrative possibilities of coping with water pollution problems are poor. Experience from two case studies and developments in many countries show that certain elements are important for operational water protection. The paper presents general consensus for legislation, the main features of legislation and administration, and procedures for dealing with pollution matters.
Water Pollution Control in Developing Areas – Training and Education
Authors: Pöppinghaus K
Published: May 2018

In training and further education in water pollution control areas in developing countries, the measures for substantial construction must be carried out as a long term strategy in the developing country and the measures for the elimination of acute emergencies as a short term strdzegy as well in the developing country and as in the donating countries.

Programmes and solutions for the elimination of the critical stage of training and for further education are derived from and presented in an analysis of the state of training and further education. The aspects of training within the targets of Water Decade are especially discussed. The bulk of aid in training and further education made by international organizations and by the Federal Republic of Germany is illustrated. The demands on the training of engineers and the training possibilities are derived.
Low-Cost Technology for Water Pollution Control in Developing Countries
Authors: Cillié G G
Published: May 2018

An estimated 80 % of all illnesses in developing countries is in one way or another related to water. In order to alleviate this most serious condition, the united Nations has initiated the “International Water Decade”, for which the estimated costs are $600 000 million, a sum which is far beyond any available means. By application of “low-cost technology” this sum could be reduced to $100 000 million which brings the objective within the reach of possibility.

Details are given of the design and methods of construction of units which are best suited to the specific requirements and which would be simple, reliable and economical to operate. These can be constructed largely from local materials and by local labour.

The need for appropriate training of both operators and the user population is stressed.
Water Recycling for Domestic and Agricultural Applications: State of the Art
Authors: Schutte C F
Published: May 2018

The state of the art of water recycling for domestic (and agricultural) applications is reviewed. Indirect reuse, indirect recycling and direct recycling of water in domestic supplies are discussed with regard to engineering, public health and quality aspects. It is indicated that there is very little difference between in= direct reuse of water containing effluents and recycling of reclaimed water for domestic applications. The most important consideration in all reuse situations is that a polluted source is used for the production of drinking water. Quality criteria are therefore required for drinking waters derived from polluted sources (or regardless of source). “Proposed Directives for the Reclamation of Treated Effluents for Direct Recycling and Reuse as Domestic Water” formulated by the South African Department of Health, Welfare and Pensions are given as an Annexure to this paper.
Water Recycling – Research Needs
Authors: Downing A L , Eden G E
Published: May 2018

The very wide spectrum of potential applications for re-used water is reflected in a need for research in many diverse areas. The most critical area is re-use for potable supplies, and here the identification of potential health effects is paramount. Other areas of application and their research needs are also considered.
Microbiology of Nutrient Removing Activated Sludge
Authors: Hart Margaret A , Melmed Leah N
Published: May 2018

The modified Bardenpho nutrient removal system is described. The build-up of microbiological life from plant start-up is recorded and Aoinetobaoter spp is identified as a major component of the Gram-negative group of bacteria in a number of plants. Problems with filamentous organisms are described.
The United States Department of Energy/United States Environmental Protection Agency Sludge Irradiation Program
Authors: Sivinski J , Ahlstrom S , McMullen W , Yeager J
Published: May 2018

Gamma radiation from cesium-137 has been shown to be effective in reducing pathogens in sewage sludge to levels where reuse of the material in public areas meets current regulatory criteria for protection of the public health. A 7,250-kilogram per day pilot plant is in operation and full-scale demonstration facilities are being developed. This paper discusses program research and engineering history related to sludge irradiation, as well as current activities and future plans.
Sea Disposal of Sludge – The U.K. Experience
Authors: Fish Hugh
Published: May 2018

A broad summary is made of the U.K. experience in sea-disposal of sewage sludge, embracing operations and effects, and control mechanisms, at disposal authority, national and international levels. The conclusion is reached that U.K. practice, while not perfect and in need of more research, is satisfactory and could be extended without causing environmental damage.
Lime Treatment of Acid Mine Water and Associated Solids/Liquid Separation
Authors: Bosman D J
Published: May 2018

Mine waters become contaminated to a varying degree with the oxidation products of pyritic materials associated with the minerals. Waters containing from 6 000 to 13 000 mg/L of sulphates and up to almost 5 000 mg/L of iron are reported. For practical or economical reasons it is not yet possible to prevent this contamination of mine water. Prevention of pollution of surface water in South Africa is mostly confined to the neutralisation of acid mine water with lime. The neutralisation reaction results in the precipitation of a voluminous sludge containing mostly iron hydroxide and calcium sulphate, when the latter is formed in excess of its solubility in water.

The sludge usually settles to volumes equal to 10 percent of the volume of the water treated, but volumes as high as 50 per cent have been found.

Through application of the “High Density Sludge” process, which comprises sludge recirculation and conditioning with lime in addition to conventional neutralisation and sedimentation, the volume of these sludges has been reduced to 0,4-2,0 per cent of the volume of water treated. The seeding of calcium sulphate resulting in a reduction of scale build-up on plant equipment seems to be an advantage of the process.

Dissolved air flotation was found an attractive alternative means of solids/liquid separation to gravity settling for water producing relatively low amounts of sludge (100 to 200 mg solids per litre). At hydraulic loadings of 7 m3/m2.h (seven times higher than gravity settling) the flotation process produced an effluent containing less than 15 mg/L suspended matter and a sludge with a density of 50 g/L.
The Environmental Impact of Coal Mining and Combustion in South Africa
Authors: Funke J W
Published: May 2018

Tonnagewise, airborne pollutants from coal combustion by far exceed waterborne pollutants from coal mining and washing. About 1 mil.t/a of SO2, probably 1 mil.t/a of fly-ash, about 0,3 mil.t/a of NOx and a few 1000 t/a of trace elements are presently emitted by ESCOM and SASOL power stations as compared with 0,1 to 0,2 mil. t/a of waterborne total dissolved solids from all coalfields. The non-quantifiable amount of airborne pollution from burning discard dumps which is not included in the above estimate can be eliminated by proper stacking methods. Insufficient information is available to ascertain the effects of airborne pollution originating mainly from the Transvaal Highveld, and thereby to obtain guidance for the course of action to be taken.

The water in the Loskop Dam receiving all mine drainage from coalfields supplying over half total tonnage of coal mined in Southern Africa is still of good, but probably deteriorating quality.
Using Acid Mine Water for Removal of Phosphates from Sewage Effluent
Authors: van der Merwe P H , Maree J P , Basson N D
Published: May 2018

An experiment was carried out at the Rondebult sewage purification works, regarding the use of underground mine water with a high iron content for phosphate removal from sewage effluents, to comply with a limit of 1 mg/ℓ soluble orthophosphates in the effluent.

The theory of iron phosphate precipitation is discussed and reference made to phosphate removal plants in Wisconsin, U.S.A. Iron and aluminium salts did not seem to harm biological life on the filter. The dosing of mine drainage appeared to inhibit nitrification, reduce the pH increase through the filters, increase TDS by about 500 mg/ℓ, but an equivalent dosage of 20 mg/ℓ Fe maintained the final P below 1 mg/ℓ at a cost of 0,1 c/m3, one-tenth of the cost if chemicals had been used.
Virus Concentration from Water Using High-Rate Tangential-Flow Hollow Fiber Ultrafiltration
Authors: Dziewulski David M , Belfort Georges
Published: May 2018

The efficacy of tangential flow hollow fiber Ultrafiltration (TFHFU) as a means of concentrating poliovirus 2 (Sabin) from large volumes of tap water was studied. Initially, hydrodynamic studies using 50-1 tap water feed solutions were conducted to evaluate transmembrane flux as a function of axial flow rates (or Reynold's numbers, Re). With increasing Reynold's number, flux-decline rates were reduced. As a result, experimental duration was shortened from 110 min at Re=300 to 30 min at Re=1728. In all cases, radial flow was assisted by a vacuum force applied to the outside of the hollow fibers. Virus recovery capability was evaluated using 20-, 50-, and 100-1 feed samples seeded with poliovirus 2 from 604 to 0.5 pfu/ml.

All virus experiments were conducted at Re=1728 and a vacuum force of 3.27 × 104 Pa. The mean duration of the 20-, 50-, and 100-1 experiments was 13, 42, and 79 minutes, respectively. The overall average virus recovery from all experiments was 69.1 ± 24.6%.

In operating the tangential-flow hollow fiber ultrafiltration module in its normal recycle-mode with low turbidity waters (<10 NTU), the expected steady flux-decline resulting from membrane fouling was not observed. Instead, the transmembrane permeation flux was maintained at a relatively constant value especially near the end of the experiments when the solute concentration in the feed increased the fastest. Increased feed water temperature resulting from the addition of pumping energy during recycle is responsible for this unexpected advantage. Final temperatures never exceeded a point at which virus inactivation would occur. For high turbidity feed waters (75 to 85 NTU), obtained by the addition of kaolin clay, virus recoveries varied from 30 to 49%, Final turbidities at the termination of a 50-1 run were from 950 to >1000 NTU. In spite of the high turbidity, the mean experiment duration for dehydrating 50 liters of turbid feed water was 39 minutes; approximately the same as for the low-turbidity tap water runs.
Removal and Inactivation of Viruses by Treatment Processes for Potable Water and Wastewater – A Review
Authors: Leong L Y C
Published: May 2018

A review of the fate on enteric viruses and phages through each major unit process used in wastewater and potable water treatment is given. Starting out with raw sewage, optimized conventional tertiary wastewater treatment with one hour contact and free chlorine residuals can be expected to remove 5-7 logs of viruses leaving <1 infectious unit/1000 liters. However, because engineered systems are not fail safe, prudent public health engineering, planning and design suggest limited direct exposure to reclaimed wastewater. Dilution, indirect reuse, or additional treatment are the suggested approaches until more research is conducted. Only under the special circumstances should direct reuse be proposed.
Virological Study of Drinking and Wastewater Disinfection by Ozonation
Authors: Hartemann Ph , Block J C , Joret J C , Foliguet J M , Richard Y
Published: May 2018

During laboratory assays of microbiological inactivation in a pilot water treatment plant (36 1/h) with drinking water artificially contaminated with poliovirus 1 and fecal indicator bacteria, ozonation shows a very strong disinfection power. There is no significant difference in the sensibility of these microorganisms to ozone. In the same laboratory plant during raw wastewater disinfection assays, the indigenous enteric viruses present a greater resistance to ozone than the indigenous fecal indicators. These results point out the important difference between the use of laboratory strains and indigenous microorganisms and confirm the interest in ozone disinfection for virucidal purposes.
Monitoring of Excess Temperature Fields
Authors: Nielsen J. Bundgaard
Published: May 2018

In the process of monitroing the impacts resulting from thermal pollution from power plants the excess heat is widely used as an indicator. One single environmental standard may however not be appropriate to cover the different physical aspects of locations for such plants.

This paper discusses various approaches (intensive and long-term measurements, modelling) and the interrelation to hydrographic conditions, and as the final result, the definition or revision of monitoring programmes.

The presentation is elucidated with examples from recent Danish monitoring programmes.
Screening Methods for Biocides
Authors: Dočkal Pavel
Published: May 2018

Assimilation of substrates penetrating into cooling systems with make-up water and from the atmosphere, or possibly from leakages from a technological process is followed by growths on heat exchanger surfaces or cooling tower fills. It is with the reuse of water especially that the need for growth suppression by chlorination and/or biocide application is acute. In the paper, screening methods for biocides based on the measurement of respiratory enzymes (dehydrogenases) activity and the level of the intracellular ATP under static and dynamic conditions, simulated by an indoor channel, are described. The result of the experiments suggest the most suitable biocide that is rapidly effective and also effective at low concentrations. The application of the described experimental method has made it possible to carry out the classification of commercial substances in the form of inhibition curves and efficiency.
Seawater Scrubber Effluent from Flue Gas Treatment – An Evaluation of Possible Ecological Consequences
Authors: Bjerkeng B , Knutzen J
Published: May 2018

Two alternative arrangements for scrubber effluent discharge are considered: to the surface layer together with the cooling water, or from a separate outlet at about 50 m depth. Effects are considered both for untreated effluent and with lime treatment and aeration of the effluent. The extention of water volumes with effluent concentrations above given limits are estimated for proposed power plant sites in the outer Oslofjord, and effects with respect to pH, oxygen, metals and polycyclic aromatic hydrocarbons are considered.

The study indicates that mixed discharge of scrubber effluent and cooling water to the surface layer without treatment may harm the marine communities by causing mean pH reduction close to 0.5 units in the upper 10 m of the outer part of the Oslofjord. Treatment of the effluent will reduce the seriously affected area and volume of surface water masses by at least 90%. No significant harmful oxygen effects are indicated for a surface discharge. By deep water discharge of untreated scrubber effluent pH would be lowered only in intermediate layers, and in a relatively minor part of the total pelagic environment, making this discharge arrangement more acceptable as regards effects from acidification. The oxygen deficit will not be serious in the primary recipient area, but there may be unacceptable reduction of oxygen renewal in the deeper layers of the inner Oslofjord. Treatment will make pH-effects from a deep discharge negligible, and reduce oxygen demand by 80%, making the effluent acceptable in these respects for many recipients. Risk of metal effects seems moderate or small, while the data on discharge of polycyclic aromatic hydrocarbons (PAH) were too uncertain for conclusions at the time of the study.
Sulphur and Chloride Deposition and Ecosystem Transport in a Strongly Acidified Lake Watershed
Authors: Hultberg Hans , Grennfelt Peringe , Olsson Bengt
Published: May 2018

This paper presents an attempt to synthesize deposition and ecosystem transport of sulphur and chloride through a strongly acidified lake watershed on the Swedish west coast. The results are based on field monitoring during a two-year period of concentrations in air, precipitation, streams and lakes. The water transport was monitored in three small watersheds and at the outlet of the total watershed.

The dry deposition was estimated from concentration measurements and deposition velocities. Besides, throughfall was monitored in one small forested watershed.

The estimated depositions into different subsystems were in good agreement with monitored outflows. The sulphur deposition to areas with coniferous forests were estimated to be 25-31 kg/ha·yr and to lake areas to about 19 kg/ha·yr. The marine part of the input is about 10%. The estimated retention of sulphur in the total watershed is 8-21%.
Biochemical Changes Associated with Luxury Phosphate Uptake in a Modified Phoredox Activated Sludge System
Authors: Potgieter D J J , Evans B W
Published: May 2018

Several chemical and biochemical parameters were monitored for in a laboratory scale modified Phoredox activated sludge system fed with settled sewage. The influence of several substrates and pH on phosphate release under anaerobic conditions was investigated.

The significance of some chemical and biochemical parameters in relation to luxury phosphate uptake is discussed and related to a concept of imbalanced provision of intermediates and other nutrients as the primary cause of enhanced phosphate uptake.
Considerations in the Process Design of Nutrient Removal Activated Sludge Processes
Authors: Ekama G A , Siebritz I P , Marais G V R
Published: May 2018

The average influent wastewater characteristics - (i) the COD concentration, (ii) the TKN/COD concentration ratio, (iii) the rapidly biodegradable COD concentration, (iv) the maximum specific growth rate of the nitrifiers at 20°C attainable in the wastewater, (v) the maximum and minimum temperatures, and (vi) the P/COD concentration ratio - are shown to govern the design of, and effluent quality from single sludge activated sludge processes for both biological nitrogen and phosphorus removal. The TKN/COD ratio governs the selection of the process type: For the Phoredox process, complete denitrification is essential to obtain excess P removal, and this is shown to be feasible only for TKN/COD ratios less than 0,07 to 0,08 mgN/mgCOD; as the TKN/COD ratio increases above 0,08, complete denitrification becomes increasingly unlikely, and the UCT or Modified UCT processes are appropriate because in these processes complete denitrification is not essential to achieve excess P removal - in these processes N and P removal can be traded off against each other depending on the critical nutrient to be removed. Primary sedimentation significantly reduces the biological nutrient removal potential of activated sludge process because it increases the TKN/COD and P/COD ratios and reduces the COD load; however it significantly reduces the process volume and total oxygen demand.