bluuebunny/crossref_metadata_2025 huggingface dataset:
Development of a New Process for Treating Uranium Mining Effluents
Authors: Huck P. M. , Anderson W. B. , Andrews R. C.
Published: May 2018

Decants from Canadian uranium mining tailings areas are treated to remove radium-226 prior to discharge into the environment. This paper describes the development of a new treatment process for these effluents. This new process differs from existing systems in that it involves the use of a fluidized bed to facilitate (Ba,Ra)SO4 coprecipitation on a granular medium of high surface area. No solids separation step is required, as the granular material is free draining. The new process has been demonstrated to provide radium-226 removal efficiencies consistently exceeding 90% in contact times of about 20 seconds. These short times are in contrast to times on the order of days for conventional pond systems or hours for mechanical systems involving stirred tank precipitation reactors.
Elevated Nitrite Occurrence in Biological Wastewater Treatment Systems
Authors: Alleman J. E.
Published: May 2018

The initial conversion of ammonium to nitrite by Nitrosomonas has traditionally been regarded as the rate-limiting step for nitrification metabolism. This perspective implicitly assumes that subsequent oxidation of nitrite by Nitrobacter occurs more rapidly, and that NO2 concentrations are consequently maintained at low, sub-mg/L values. However, numerous bench- and full-scale nitrification systems have reportedly encountered elevated nitrite concentrations. Several concerns are generated by this circumstance, including: a) an increased chlorine demand, b) an increased effluent nitrogenous oxygen demand, c) potential nitrite toxicity, and d) possible nitrosamine formation. This paper consequently provides an overview of seven conditions which could lead to elevated nitrite occurrence in biological nitrification systems.
Settling of Nutrient Removal Activated Sludges
Authors: Pitman A. R.
Published: May 2018

This paper surveys the settling properties of activated sludges from four biological nutrient removal plants. Empirically derived constants used in the settling flux theory are correlated with more traditional measures of settling properties such as the SVI. An easy method of using the settling flux approach to clarifier design and operation is presented and a new parameter describing the settling properties of sludges is proposed. Typical values of constants describing the settling properties of nutrient removal sludges are presented. It was found that the factor most influencing sludge settling properties was the degree of aeration in these plants.
Floc-Forming Substances Extracted from Activated Sludge with Ammonium Hydroxide and EDTA Solutions
Authors: Sato T. , Ose Y.
Published: May 2018

The authors attempted to extract the floc-forming substances by sequential extraction with NH4OH and EDTA solutions from activated sludge. Some fractions had the capacity for floc formation in acidic ranges and some of the fractions were further fractionated by Sephadex G-50. There is a possibility that low molecular weight substances, except metallic ions related to floc formation and floc-forming substances in activated sludge are not limited to one special substance.
Highly Efficient Anaerobic Digestion with Thermal Pretreatment
Authors: Hiraoka M. , Takeda N. , Sakai S. , Yasuda A.
Published: May 2018

The effectiveness of an anaerobic digestion process with thermal pretreatment at a comparatively low temperature was examined. The waste activated sludge was thermally pretreated in the process. A laboratory scale experiment and a pilot plant study were conducted. Changes in volatile acids concentration, in major constituents of sludge and in molecular size distribution were examined before and after thermal pretreatment and anaerobic digestion. Thermal pretreatment resulted in an increase of more than 30 percent in digestion gas production. The major substrates decomposed were fats in the pilot plant study. Glyceride fatty acids are decomposed with thermal pretreatment and produce volatile acids such as acetic and propionic acids. The volatile acids are directly utilized by anaerobes to produce methane. Organic matter such as fats and carbohydrates are depolymerized with thermal pretreatment and produce soluble intermediate compounds such as higher fatty acids. The intermediates are utilized in the anaerobic digestion process. These two major effects facilitate the methane production process.
Fractionation of Heavy Metals in Sewage Sludges
Authors: Oake R. J. , Booker C. S. , Davis R. D.
Published: May 2018

Metals (Cd, Cr, Cu, Ni, Pb and Zn) have been fractionated in representative sewage sludges (primary, secondary, digested) by a sequential extraction procedure using KNO3 1M (removes the ‘exchangeable' fraction), KF 0.5M (‘sorbed'), Na4P2O7 0.1M (‘organic'), Na2EDTA 0.1M (‘carbonate') and HNO3 6M (‘sulphide'). Major differences according to sludge type were not seen. Cd occurred mainly in the ‘carbonate' fraction and 38–62% of Cr was in the ‘organic' fraction. 43–70% Cu was in the sulphide fraction whilst >40% of Ni was extracted in the ‘exchangeable/sorbed' fractions. Pb was found predominantly in the ‘organic' and ‘carbonate' fractions and Zn in the ‘organic' fraction. The complete extraction procedure removed 54–100% of the total metals content of the sludges. Changes in fractionation caused by drying, storage and time of extraction are reported. The results form the first part of a detailed investigation into the chemistry of metals in sewage sludge.
Factors Controlling the Survival of Viruses in Groundwater
Authors: Yates Marylynn V. , Gerba Charles P.
Published: May 2018

The purpose of this work was to define factors which control virus survival in groundwater. Groundwater samples collected from throughout the United States were inoculated with the coliphage MS-2 and the rate of virus inactivation determined. All samples were incubated at the temperature of the native groundwater. All samples were analyzed for pH, nitrates, ammonia, turbidity, total dissolved solids, and calcium, magnesium and total hardness. Multiple regression analysis of the chemical variates indicated that temperature and calcium hardness were significantly correlated with the rate of virus die-off. Temperature alone account for 60% of the variation in decay rate. Using all variates, 94% of the variation could be predicted.
Phosphorus, Nitrogen and Chlorophyll-A Concentrations in a Typical Dutch Polder Lake, Tjeukemeer, in Relation to its Water Regime Between 1968 and 1982
Authors: De Haan H. , Moed J. R.
Published: May 2018

The mean concentrations of total phosphorus (P) and total nitrogen (N) in the polder lake Tjeukemeer during the period April - September (summer season) between 1968 and 1982 were 0.215 and 3.8 mg/l, respectively. These values exceeded those laid down by the Dutch water authorities for standard water quality. Though the mean summer chlorophyll-a (chl-a) concentration of 116 µg/l during 1968 - 1982 was comparable with that for the basic quality standard, the mean concentrations between 1977 and 1982 were from 1.3 to 2.1 as high.

Multiple regression analysis of the mean concentrations of total P and total N and climatological and hydrological data demonstrated that the P and N concentrations in Tjeukemeer in summer and in winter were significantly correlated with the deficit or surplus of water and consequently with the man-made regime, namely the inflow and outlet of water in SW Friesland.

Between 1979 and 1982 the ratios (w/w) of the mean concentrations of total N and total P and those of particulate N and particulate P in summer were less than 16 and 10, respectively, indicating that phytoplankton growth was N rather than P limited.
Organic Removal Mechanisms in Biophysical Treatment Systems
Authors: Schultz J. R. , Keinath T. M.
Published: May 2018

An experimental program was conducted to evaluate the significance of enhanced biodegradation, bioregeneration, and metabolic end product (MEP) adsorption in a bench-scale biophysical reactor using phenol as the substrate. Radiotracer methods and a desorption-extraction procedure that measures the amount of adsorbed phenol were used to discriminate between the various mechanisms. The results showed the major benefit of PAC addition under steady-state conditions to be MEP adsorption. Furthermore, adsorption reversibility was established as the controlling mechanism for bioregeneration. Reversibly adsorbed phenol could be desorbed to regenerate the PAC, but irreversibly adsorbed MEP could not. PAC, therefore, acts as a storage reservoir during shock loads via an adsorption-desorption sequence.
Behaviour of Intracellular Polyphosphate in the Biological Phosphate Removal Process
Authors: Mino Takashi , Kawakami Tomonori , Matsuo Tomonori
Published: May 2018

In this study the functions of the intracellular polyphosphate in the biological phosphorus removal process were investigated from biological point of view. The STS method was used for the determination of polyphosphate and the fractionation of the intracellular phosphorus compounds. The lowmolecular polyphosphate and the highmolecular polyphosphate can be determined separately in this method. The radiotracer experiments were performed in which 32P-labeled orthophosphate was used as a tracer. The chemical analyses of phosphorus and the radioactivity measurement were made simultaniously in the course of the anaerobic oxic process. From the results of a radiotracer experiment the mass transfer of phosphorus among the phosphorus compounds was calculated. It was suggested that the lowmolecular polyphosphate served as the energy source under the anaerobic conditions and that the highmolecular polyphosphate served as the phosphorus source for the growth reactions. Some models for the phosphorus transfer in the high phosphorus accumulating microorganisms were proposed.
New Strategies for the Isolation of Microorganisms Responsible for Phosphate Accumulation
Authors: Suresh N. , Warburg R. , Timmerman M. , Wells J. , Coccia M. , Roberts M. F. , Halvorson H. O.
Published: May 2018

Several strategies were used to isolate organisms involved in the uptake and subsequent release of inorganic phosphate from waste water sludge. These included direct staining for polyphosphates (polyP), growing in 32P inorganic phosphate followed by autoradiography, resistance to dicyclohexyl carbodiimide (DCCD), an ATPase inhibitor, and isolation on the basis of the buoyant density of the cell. Among those microorganisms isolated, three were identified as Acinetobacter lwoffii, A. calcoaceticus and Pseudomqnas vesicularis. The Ps. vesicularis culture had 31% of phosphate as polyP. 31P NMR analysis of the whole cells revealed the presence of polyP when the cultures were grown aerobic-ally to the late stationary phase and its subsequent loss during anaerobic incubation. Loss of polyP was also associated with a decrease in buoyant density of the cell. In the presence of DCCD, there was a decrease in the polyP peak, but a substantial increase in the sugar phosphates which is consistent with a hypothesis that polyP is used as a reserve energy source, Ps. vesicularis cells showed a two-fold increase in the level of polyphosphatase during early stationary phase, but a thirty fold increase in polyphosphate kinase activity during late stationary phase. This increased enzyme activity is consistent with the increased polyP synthesis during late stationary phase.
Some Physiological Characteristics of Acinetobacter spp. Accumulating Large Amounts of Phosphate
Authors: Deinema Maria H. , van Loosdrecht Mark , Scholten Annie
Published: May 2018

Acinetobacter strain 210A has been grown in batch and continuous cultures in an acetate medium. The P content of the cells varied from 6–10% of the dry matter and phosphate uptake continued for months as long as carbon and nitrogen source, inorganic salts and oxygen were present.

The growing ( = metabolizing) bacterial cells released phosphate under anaerobic conditions. Addition of CO2, acetate and ethanol or other reduced carbon sources stimulated the rate of the phosphate release but after 24 hours of anaerobiosis the obtained results with or without additions were similar.
The Role of Bacterial Phosphate Metabolism in Enhanced Phosphorus Removal from the Activated Sludge Process
Authors: Lötter Laurraine H.
Published: May 2018

This study was undertaken in an attempt to gain greater insight into phosphate metabolism in relation to biological phosphorus removal. Bacterial population studies of activated sludge plants revealed the predominance of Acinetobacter spp. Studies of these isolates showed a number of strains capable of reducing nitrate to nitrogen.

Growth of Acinetobacter isolates on a variety of carbon sources showed that not only growth but also polyphosphate accumulation is stimulated by short chain carbon compounds, such as acetate and butyrate, which are products of bacterial fermentation. Assays of anaerobic zone mixed liquor samples indicated high activity of key enzymes in the formation of these compounds. Phosphate uptake under various conditions underlined the sensitivity of bacterial phosphorus metabolism to external factors. The origin of the orthophosphate released in the anaerobic zone points strongly to polyphosphate hydrolysis to orthophosphate rather than the formation of adenosine triphosphate (ATP). The anaerobic zone is seen as a qualifying zone where cells are preconditioned for optimum phosphorus removal in subsequent zones.
Exchange of Organics, Phosphate and Cations between Sludge and Water in Biological Phosphorus and Nitrogen Removal Processes
Authors: Arvin E. , Holm Kristensen G.
Published: May 2018

The stripping of phosphorus, potassium and magnesium, and uptake of organic substrate and calcium was studied in the anaerobic reactors of two biological phosphorus and nitrogen removal plants. Most of the experiments were performed in batch systems simulating the function of the anaerobic reactor. Acetate-, propionate- and lactate addition to the sludge under anaerobic conditions resulted in a significant P-release. The P-release with glucose was significantly smaller. Approximate values for the ∆ P/∆COD ratios were estimated. Average ∆ K/ ∆P and ∆Mg/ ∆P values were estimated to about 0.29 and 0.25 mg/mg, respectively.

Phosphate appears to be precipitated simultaneously with the biological P-stripping. In the plant under detailed investigations, about 60% of the total phosphate is precipitated, irrespective of the total P-content in the sludge. Calcium and magnesium are the dominating counterions, the (Ca+Mg)/P molar ratio being about 1.1. Some iron appears also to be associated with the phosphate, 0.6% of the dry sludge.
The Behaviour and Fate of Arctic Oil Spills
Authors: Bobra A. M. , Fingas M. F.
Published: May 2018

A brief overview is provided, based on several recent reports, of the dominant factors and processes which influence the behaviour and physical fate of spilled crude oil in the remote harsh Arctic offshore regions. These factors and processes include physical-chemical properties, evaporation, dispersion, dissolution, emulsification, physical movement and interaction with ice. Rates of the individual dominant processes for a typical Beaufort oil in the Beaufort Sea under different physical environments are approximated and applied to various spill scenarios. Research needs in this field are summarized.
Accumulation of Airborne Trace Pollutants by Arctic Plants and Soil
Authors: Thomas W.
Published: May 2018

Plant and soil samples from 4 locations in Spitsbergen (Norway) were analysed for major ions, heavy metals, polyaromatic hydrocarbons (PAH) and chlorinated pesticides.

The results indicate that trace amounts of these substance groups result from a number of different sources, namely from subsoil material, local emissions and long range atmospheric transport. A comparison of inorganic and organic micropollutant concentrations allows a distinction between trace substance uptake from soil or air.

The correlation of plant and air concentrations makes it obvious that elevated accumulation rates of heavy metals in plants result from low level transport of particles. PAH are very effectively retained by species with large surface areas and represent particle concentrations in the air. Benzohexachloride in plants results from precipitation water rather than from direct uptake of gaseous traces.
Experimental Determination of Intrinsic Kinetic Coefficients for Biological Wastewater Treatment Systems
Authors: Shieh Wen K. , Mulcahy Leo T.
Published: May 2018

An experimental procedure which allows for a direct determination of intrinsic kinetic coefficients is described. The experimental apparatus(a rotating disk biofilm reactor) used offers a relatively simple, yet rigorous means for examination of factors affecting biokinetics, i.e., simultaneous mass transfer and biochemical reaction. Intrinsic kinetic coefficients of biological denitrification with methanol as the organic carbon source were determined using the proposed experimental procedure and these intrinsic kinetic coefficients were capable of providing an accurate prediction of nitrate-nitrogen profiles observed in a laboratory-scale fluidized bed biofilm reactor receiving the same feed.
Modeling Mass Transfer in Biological Wastewater Treatment Processes
Authors: Kissel John C.
Published: May 2018

Parameters characterizing intrasolid, liquid/solid, and gas/liquid mass transport phenomena in biological treatment systems are required if mass transfer is to be included in process models. Estimates of such parameters are presented and discussed. Collective and individual effects of mass transfer resistances are illustrated by computer simulation of a high-rate trickling filter.
Procedures for Determining Influent COD Fractions and the Maximum Specific Growth Rate of Heterotrophs in Activated Sludge Systems
Authors: Ekama G. A. , Dold P. L. , Marais G v. R.
Published: May 2018

The influent COD of municipal wastewaters has been categorised into fractions: readily (soluble) and slowly (particulate) biodegradable, and soluble and particulate unbiodegradable. Procedures are presented for determining the division into these four categories, as are experimental methods for determining the maximum specific growth rate of the heterotrophs within the IAWPRC Task Group model structure. Some of the procedures are dependant on knowledge of the heterotroph yield and endogenous mass loss rate constants; comment is made on suggested values.
Nitrate versus Oxygen Utilization Rates in Wastewater and Activated Sludge Systems
Authors: Henze Mogens
Published: May 2018

Respiration rates for nitrate and oxygen are compared. Raw wastewaters vary much in these rates and the same holds for activated sludge systems. The denitrifying activity may range from 0-80 per cent of the oxygen activity. It is important to take these variations into consideration, when modelling complex activated sludge processes. Of similar importance are the amounts of active biomass in raw wastewater, as these amounts can exceed those produced in the activated sludge plant itself, and thus significantly can influence the overall composition of the active biomass.
An Investigation of the Treatment and Recycling of Oil Refinery Wastewater
Authors: Misković D. , Dalmacija B. , Živanov Ž , Karlović E. , Hain Z. , Marić S.
Published: May 2018

The objective of the present investigation was a high level of purification of the wastewater from an oil refinery achieved by using some improved methods yielding an effluent suitable for recycling into the process. All the investigations were carried out on a continuous laboratory pilot system consisting of the following units: dissolved air flotation (DAF), sedimentation, double-stage microbiological reactor, and adsorption columns filled with granular biologically activated carbon (GBAC).

A high degree of COD reduction close to 100% (precisely, 99.95 %), as well as removal of nitrogen compounds of 72% was achieved during a relatively short retention time within the range of 15-16.5 hrs. The DAF technique combined with gravitational separation was used to achieve the recovery of free oil matter up to 98%, without any preliminary conditioning. After the sedimentation of coagulated and flocculated dispersed oils, the microbiological oxidation of dissolved matter was accomplished by using two kinds of activated sludge for easy and hard degradable organics. Using the continuously bioregenerating GBAC, an effluent having a lowered COD value to about 9 was obtained. At the same time, the denitrification process took place. According to the obtained results the treated oil refinery wastewater can be recycled into the process, or discharged into a water recipient of a low self-purifying capacity.
Evaluation of the Sanitary Quality of Marine Recreational Waters and Sands from Beaches of the São Paulo State, Brazil
Authors: Sanchez P. S. , Agudo E. G. , Castro F. G. , Alves M. N. , Martins M. T.
Published: May 2018

In order to evaluate the sanitary quality of marine recreational waters and sand at some beaches of São Paulo State, Brazil, a 19-month study (1984-1985) was undertaken at nine sampling stations, and a total of 342 samples of sea water and sand were analysed for total and faecal coliforms, faecal streptococci, Pseudomonas aeruginosa and Salmonella. In sand samples Candida albicans, dermatophytes, Pitryrosporum, helminth eggs and protozoan cysts were also researched. Sea water samples were also analysed for enteroviruses and, in the second part of this study, for enterococci also. The results have shown some areas with high levels of faecal contamination in sea water and sand. The Brazilian recommended faecal coliform limit was exceeded in 31% of the sea water samples. Out of 171 sea water samples analysed, 10.5% were positive for Salmonella and 3.5% for enteroviruses. Positive results for C. albicans were observed in 18.7% of the sand samples and helminth eggs were detected in 12.9% of these 171 samples; Pityrosporum, dermatophytes and protozoan cysts were not detected.
Evaluation of Bacteroides fragilis Bacteriophages as Indicators of the Virological Quality of Water
Authors: Jofre J. , Bosch A. , Lucena F. , Gironés R. , Tartera C.
Published: May 2018

Bacteriophages infecting Bacteroides fragilis 40 were found in all kinds of sewage polluted samples. In contrast, they were never recovered either in non-faecally polluted samples or in samples only polluted by wildlife. In simulated laboratory experiments, a selected bacteriophage, B40-8, active against B. fragilis 40 did not replicate either in aerobiosis or under anaerobic conditions, when the culture medium was substituted by either fresh water, seawater or sediments. Inactivation rates of the same bacteriophage were studied in comparison with other viruses such as poliovirus 1, simian rotavirus SA11 and f2 coliphage, showing decay rates similar or inferior to the ones of the other viruses studied. Results herein shown indicate that bacteriophages infecting B.fragilis may be good candidates for a surrogate indicator of human viruses in the environment.
History and Application of Microbiological Water Quality Standards in the Marine Environment
Authors: Salas H. J.
Published: May 2018

The history and application of microbiological water quality standards in the marine environment for primary contact recreation and shell fish harvesting are presented. Special note is taken of recent investigations which concluded that Enterococci, as an indicator organism, provided the best correlation with gastrointestinal symptoms attributed to swimming in contaminated waters. The linear relationship developed between mean enterococcus density per 100 ml and swimming associated rate for gastrointestinal symptoms per 1000 persons is presented along with the U S Environmental Protection Agency proposal to adopt Enterococci as the primary indicator organism in lieu of total and fecal coliforms.

One school of thought which considers microbiological guidelines/standards for primary contact recreation relevant to public health protection is compared to the opposing viewpoint that such guidelines/standards are merely useful for aesthetic considerations.

International, national and local microbiological guidelines and standards in the marine environment are presented to provide a range for the water quality planner. The simple adaptation of a particular set of standards is considered inappropriate without a thorough review of local circumstances and local/ national economic factors. Also, caution should be exercised in directly applying quantitative relationships between health risk and indicator organism in other areas where the general health and immunity of the local population may be different.
Microbiology of Anaerobic Digestion
Authors: Novaes R F. V.
Published: May 2018

This paper presents a general overview of studies conducted with microorganisms involved in the anaerobic digestion process, and also some ways of applying these studies as fundamental tools in the understanding, improvement and control of the anaerobic treatment of residuals.
Development of Technology for the Use of the UASB Reactor in Domestic Sewage Treatment
Authors: Vieira Sonia M. M. , Souza Marcos E.
Published: May 2018

The lack of a simple and economic option for the treatment of sewage created the need to develop and make the UASB reactor adequate for low strength wastes. Thus a UASB reactor with 106 ℓ capacity was built, which was specially designed for sewage treatment. Several treatability tests were conducted with raw and settled domestic sewage, with only A hours of hydraulic retention time. This proved the reactor's technical feasibility in treating raw sewage at ambient temperature in São Paulo. Based on these experiments, the reactor was scaled up to 120 m3 and built for the treatment of raw sewage at ambient temperature. The operation is in its initial phase, and good COD removals are already being observed, although steady state has not been achieved yet. Since the cost of the system was extremely low, it is a feasible option to be applied in this country.
Utilization of Vinasse Effluents from an Anaerobic Reactor
Authors: Costa F J. C. B. , Rocha B B. M. , Viana C. E. , Toledo A. C.
Published: May 2018

An anaerobic reactor was developed to biodigest alcohol distillery wastes. A further post-treatment of the effluent reduced the level of pollution to the point of eventually discharging into streams and rivers. The present work also analyses the use of biodigested vinasse as a source of food for fish.

Very high efficiencies were obtained during primary and secondary treatment of vinasse effluent, as demonstrated by the greatly reduced organic load. The utilization of the treated effluent as a source of fish food presents an excellent alternative for the Brazilian alcohol industry.
Co-Disposal of Municipal Refuse and Industrial Waste Sludge in Landfills
Authors: Pohland F. G. , Gould J. P.
Published: May 2018

The results of a 2-year pilot-scale investigation on the codisposal of heavy metal sludge with municipal refuse, under the influence of leachate containment and recycle, are used to illustrate and describe the effects of various metal loadings on the normal progress of waste stabilization and to assess associated assimulative capacity. Evidence of metal precipitation as sulfides or hydroxides and subsequent removal by filtration and sorption in the refuse mass was demonstrated. Conversely, the mobilization of heavy metals was shown to be enhanced by complexation with humic-like substances which also tended to reduce overall toxic effects. Whereas, high heavy metal loadings exhibited a clear inhibitory effect, a definite capacity for assimilation and acclimation at low to moderate levels was established.
Estuarine, Coastal and Ocean Pollution: EEC Policy and Research
Authors: Bourdeau P. , Barth H.
Published: May 2018

This paper presents an overview of the policy and research of the European Community concerning estuarine, coastal and marine pollution.

The structure and implementation of the European Community marine environmental policy, intended to combat the various types of pollution of the sea, and to protect the European waterways and the marine environment are described. Particular reference is made to actions dealing with oil pollution and other harmful chemical substances released into the sea.

The environmental research programme, aimed at providing scientific support to the environmental policy of the European Community, addresses short-, mid- and long-term problems. Thus it deals mostly with pollution : its sources, detection, fate, pathways, environmental and genetic effects; and abatement and prevention of pollution by oil, wastes, fertilizers, heavy metals and other environmental chemicals. It is also increasingly concerned with improving the understanding of the functioning of estuarine, coastal and marine ecosystems.

The future orientations of the Community's marine environmental policy and research are discussed. These will stress the preventive aspects of environmental protection.
Ecological Impacts of the Construction of Dams in an Estuary
Authors: Leentvaar J. , Nijboer S. M.
Published: May 2018

This paper deals with the ecological impacts of alternative methods of constructing dams in an estuary. The main options available were:using concrete blocks and rubbleusing only sand.

The advantages of using sand are that it is available locally and it is cheaper than concrete blocks and rubble. However, the application of sand in a tidal basin requires low current velocities. During the final closing period of the dams, these velocities can be reduced by using the storm-surge barrier (to be built in the mouth of the Eastern Scheldt estuary) in two ways: either reducing the tidal amplitude or reducing the tidal frequency. The tidal reduction influences the vertical amplitude and current velocities, thereby decreasing the intertidal area, and the biomass and production of microphytobenthos and macrozoobenthos. A reduction of the horizontal tide leads to a reduction of the exchange of water between the North Sea and the estuary, with a decrease in current velocities. These phenomena affect the concentration of suspended and dissolved material; in particular, salt concentrations decrease with possible stratification.

This paper describes the effects of different closing procedures on natural ecosystems and fisheries. The study resulted in a policy analysis and was presented to decision-making politicians.
Ecological Impact of an Oil Spill: Utilization of Biological Indicators
Authors: Glémarec M.
Published: May 2018

One of the major difficulties for science today is still the understanding of how a whole ecosystem operates. However, perturbations affecting the normal functioning of an ecosystem can be evaluated and monitored in time, from trophic or dimensional points of view, by studying the macrofauna which is found in the middle of the trophic or dimensional hierarchies of the ecosystem. Organisms in this category are greater than 1 mm in size, and sampling is effected by means of quantitative grabs. Most of these organisms have life cycles generally ranging between 1 and 3 years. They are distinct from other fauna of larger size and longer life cycle, but they are also scattered, and are therefore difficult to sample.

The effects of the “Amoco Cadiz” oil spill on the fine sand ecosystem are evaluated by means of macrofauna which represent medium hydrodynamic conditions. Different species were classified in ecological groups according to their sensitivity to hydrocarbons and to organic matter overload. The two parameters, specific richness and abundance per square meter, indicate the structure of the macrofauna population, and a third parameter, the biomass, can also be used. The study of these factors and their evolution in time, as well as the ecological groups, enables definition of the degradation, recolonization and restructuring conditions. Finally, predators such as fish juveniles regulate these communities; six years after the “Amoco Cadiz” oil spill, even if this fine sand ecosystem reaches a new equilibrium, it is still too early for the regulation processes by predators to take place.
Present State and Future Direction of Countermeasures for Pollution from Domestic Wastewater in Japan
Authors: Fujiwara Masahiro
Published: May 2018

Japan is poorly provided with sewerage facilities especially in non-urban areas. Of domestic wastewater not discharged into the sewage system only night soil is treated, and the remaining domestic wastewater (grey water) is discharged untreated into public water bodies. Regarding the current water pollution load, the proportion of domestic wastewater, especially that of grey water, is increasing. It is not clear, however, who is legally responsible for grey water, and there is little interest in treatment of such grey water. Thus, the development of domestic wastewater pollution countermeasures will be an important task. This paper classifies the systems popularly used in Japan to treat domestic wastewater into several types, and describes the administrative regulations, and Government and other assistance, relating to them. Also, some promising systems for the treatment of domestic wastewater are presented as examples. Finally, future policies on domestic wastewater pollution countermeasures are discussed.
Prolonged Effect of Land Disposal of Human Wastes on Soil Conditions
Authors: Saber M S. M.
Published: May 2018

Land disposal of human wastes is a comprehensive issue, where a series of aspects have to be considered. Few, if any, alternatives exist to this technology. No doubt future emphasis will be on sewage farming, which should result in the cultivation of new arid land. This paper addresses the prolonged effect of land disposal of human wastes on soil properties, as well as on the dissemination of enteric pathogens. In order to assess this impact, soil samples were collected from Gabal el Asfar sewage farm in Cairo to represent sandy soils irrigated solely, by surface flooding, with decanted sewage effluent for 0, 2.5, 5, 10, 15, 20, 30, 45 and 60 years. Sewage farming tended to build up the soil microbial population, particularly during the first five years. In all soils, human wastes increased total bacterial counts and promoted the proliferation of the physiological groups. This population would accelerate the oxidation of organic matter to available nutrients. It also resulted in a high increase in nitrogen, phosphorus, micro-nutrients, organic carbon and raised the water holding capacity and exchangeable cations. However, the prolonged use of sewage effluent would disturb the balance of nutrients in soil, as the pH shifted towards acidity. The most interesting observation in the present work is to record that neither soluble salts nor micro-nutrients reached any injurious level. But land disposal of human wastes should be excercised with caution and if it is intended to be applied, salts, pH and nutrient elements should be checked occasionally. From the hygienic point of view, faecal E. coli, which is considered to be an indicator for enteric pathogens, gave positive results in all sewaged soils. Hence, it is recommended, from the sanitary point of view, that no crops which come in contact with sewage effluent should be cultivated in a sewage farm.
Use of Sewage Sludge on Land in the United Kingdom
Authors: Davis R. D.
Published: May 2018

In the UK 30 million wet tonnes (1.2 × 106 tonnes dry solids (tds)) of sewage sludge are produced annually and its treatment and disposal costs ₤200 million per annum. Utilisation on agricultural land is the most economic disposal option for inland sewage treatment works and this route accounts for about 40% of sludge. Guidelines for sludge utilisation on land in the UK are designed to prevent contamination problems by metals, disease transmission, public nuisance and water pollution. The Council of the European Communities has introduced a Directive to be implemented in 1989 which will provide the statutory baseline for domestic guidelines in the countries of the European Community. UK guidelines and the CEC Directive are discussed in the context of potential contamination problems and the value of sludge to farmers.
Sludge in Agriculture: the European Approach
Authors: Scheltinga H M. J.
Published: May 2018

The sludge production in the European Community can be estimated to be about 6 million tons of dry matter per year. By 1990 this quantity may have doubled. About 30% of the annual production is used in agriculture. Cooperation in the field of scientific and technical research has been actively promoted by the European Community together with European Non-Member states. One of the earliest examples of such a cooperation is the Concerted Action “Treatment and use of sludge and liquid agricultural wastes” (Cost 681). Participating Non-Member states are Austria, Finland, Norway, Sweden and Switzerland. Canada takes part on a somewhat different basis. The main purpose of the Cost-action is to acquire scientific and technical knowledge and to disseminate the results to the participants and others interested. Until now there was no provision for direct funding of research projects by the Commission. The Cost-action is managed by a concertation committee in which the participating countries and the Commission are represented. The action coordinates in the most flexible way, in the countries involved, all relevant research concerning sewage sludge treatment and its optimal use in agriculture, taking into account the evaluation of possible harmful effects for public health and environmental protection.

Five Working Parties were set up, dealing with the following programmes:–Assessment of the best sludge treatment techniques, and of their cost and reliability, in order to get valuable products for agricultural purposes (WP-1).–Improvement and harmonisation of sampling procedures and analytical methods for the control of organic and mineral pollutants in sludges and soils (WP-2).–Measures to be taken to prevent harmful effects to public health due to sludge spreading or storage in the environment (WP-3).–Evaluation of the agricultural value of sludges for crop and grass production, forestry and soil reclamation (WP-4).–Prevention of long- and short-term environmental risks for the atmosphere, ground water and soil micro-organisms by sludge spreading (WP-5).
Landfarming in the Treatment by Cetrel of Organic Wastes from a Petrochemical Complex – Design, Operation and Results
Authors: Alves J. O. , Valente M. C. M. , Simões M. A. P. , Santos M. G.
Published: May 2018

In the beginning of 1983, CETREL S/A, based on the experiments carried out in other countries, put forth the idea of treating organic industrial wastes generated by COPEC, especially atoxic biodegradable sludges, through LANDFARMING. Therefore, in 1984 two “Farms” were implemented, in an area of 20 hectares.

In view of the pioneering ventures in Brazil for the disposal of industrial wastes of various sources, operation controls have been and still are a continuous learning process, stimulating research on the insertion or adaptation of governing parameters in the process.

In that connection, it is our intention to show the characteristics and procedures adopted with regard to Design, Operation, Control/Monitoring, Pilot Scale Tests and Results.
Effects of Irrigation with Vinasse and the Dynamics of its Constituents in the Soil: I – Physical and Chemical Aspects
Authors: Cunha R. C. de A. , da Costa A. C. S. , Maset Filho B. , Casarini D. C. P.
Published: May 2018

With the intention of understanding the dynamics of some of the constituents of vinasse, and to evaluate the risks of groundwater pollution due to sugarcane irrigation with this wastewater, a study was carried out from October 1984 to June 1985 in Piracicaba, São Paulo State, Brazil. Vinasse was sprinkled at a rate of 800 m3/ha by a hydraulic big gun. This applied 804.76 kg/ha of potassium and 305.86 kg/ha of nitrogen. The leaching of K and NO3. was measured by the use of tensiometers and tension lysimeters installed at various depths. It was concluded that the methodology is acceptable as a procedure for field research. Potassium and nitrate did not leach as expected. After 6 months, only 0.34 kg/ha of potassium and 0.41 kg/ha of nitrate had leached to below 120 cm. The roles of soil and plants were very important in preventing groundwater pollution. The soil retained part of the applied potassium, and the sugar-cane plants absorbed a large part of the N and K applied to the soil.
The Development of Water Quality Indices for Operational Management
Authors: House M. A. , Ellis J. B.
Published: May 2018

The derivation, structure and application of a Water Quality Index (WQI) for the classification of surface water quality is discussed and the efficiency of the developed WQI is compared with the standard UK classification system of the National Water Council (NWC).The general WQI is developed through the objective and rigorous selection, transformation and weighting of determinands with rating curves based on legal standards and quality directives or guidelines. Three further indices intended for potable supplies and evaluation of toxicity are also discussed. The utility of the developed index for operational management is demonstrated by a comparative study with the NWC classification for a number of rivers in the Greater London region. The flexibility and advantages of a WQI approach in providing potential cost benefit/assessments for water quality on both temporal and spatial scales are also highlighted.
The Applicability of the Wastewater Treatment Plant in Othfresen as Scientific Documentation of the Root-Zone Method
Authors: Brix Hans
Published: May 2018

Up to the present time documentation for the functioning of the root-zone method is almost exclusively based on data from the Othfresen plant in Western Germany, a 22.5 ha large wetland, which since 1974 has received municipal wastewater. The present paper describes the working experiences from Othfresen, and evaluates the applicability of the data from Othfresen as basis for the scientific documentation of the root-zone method in general.

It is concluded that the data from Othfresen are useless in the documentation of the root-zone method for the following reasons: (a) The loaded area has not until 1985 been well-defined, (b) the soil in the treatment plant is very atypical (old mine debris), (c) a major proportion of the wastewater does not penetrate the soil, but distributes on the surface as overland flow, (d) the quality of the water in the “defined” outlet, i.e. a well consisting of a PVC-tube, has no relation to the treatment of wastewater in the area, and (e) the true effluent to the recipient is of varying quality, especially as far as nitrogen is concerned.

It is therefore necessary to await results from well-controlled experimental treatment plants before the functioning and the applicability of the root-zone method can be properly evaluated.
Domestic Wastewater Treatment in Tanks Planted with Rooted Macrophytes: Case Study; Description of the System; Design Criteria; and Efficiency
Authors: Boutin C.
Published: May 2018

For several years, the CEMAGREF has been interested in the study of treatment plants adapted to rural areas. In this field, “macrophyte beds”, as a new procedure in water treatment, has been closely followed.

This treatment plant is made up of a series of watertight tubes filled with gravel and rooted with aquatic plants. Since autumn of 1982, this plant has been treating the wastewater of a rehabilitation center which functions according to a scholastic calendar. Receiving loading of 28 population equivalents, the plant must be able to cope with loading variations reaching a factor of 6. The total planted surface is 63 m2, thus 2.5 m2 per population equivalent.

The different series of measurements taken during an annual plant cycle show that:–the abatement of the organic loading (COD, BOD5) reaches 85% to 90%;–the elimination rate of total nitrogen is near 50%;–the phosphorus is mineralised but is not retained by the treatment.

The samplings of effluent discharge, taken several times over a three year study period, showed that the once satisfactory discharge had degraded. The origin of this degradation should be looked into.

The first results (as described above) will be completed by those obtained during a study which is being conducted on a larger scale (500 population equivalent). This plant was put into use in September 1985 and receives a loading of domestic wastewater from an urban neighborhood.

The research project has as its aim to optimize both the economic and operational aspects of the treatment plant to answer the real needs of small rural communities.
Research on the Physiological Basis of Population Dynamics in Relation to Ecotoxicology
Authors: Kooijman S A. L. M. , Hanstveit A. O. , van der Hoeven N.
Published: May 2018

One of the main obstacles that hampers ecotoxlcology is the poor insight into the relationship between physiological and population dynamics. The role of laboratory experiments, modeling, mathematical analysis and computer simulation studies is discussed in research aiming at this relation. Energy and nutrient budgets of organisms are found to be of vital importance. This paper evaluates the progress that has been made in concrete efforts to work out energy and nutrient budgets for simple freshwater plankton systems stressed by toxic chemicals with different modes of action.
Developing Automated Multispecies Biosensing for Contaminant Detection
Authors: Morgan E. L. , Young R. C. , Crane C. N. , Armigate B. J.
Published: May 2018

Automated biomonitoring may provide real-time functional information from cause/effect relationships between developing toxicity and a representative aquatic animal. However, since the applicability of single-species biomonitoring information may be subject to question when viewed in light of community toxicity and ecological quality control programs, we developed a computer-assisted multiple species biosensing system for water quality monitoring. In addition to fish, emphasis was placed on detecting species-specific bioelectric potentials produced by unrestrained mussels, burrowing mayfly nymph (Hexagenia spp.) and preliminary work with case building caddis fly larva. A specially designed differential amplifier was used for measuring bioelectric potentials induced from various activities of test subjects. Selected responses were detected as discrete analog signals, digitized and filed on computer disk. A management program provided various means for data gathering, filing and retrieval. Two pilot biomonitors were developed, each consisting of an instrumentation minicomputer with up to 12 biosensor input channels and various output peripherals including hardcopy and modem. These systems, combined with an IBM-XT personal computer based biomonitor interfaced to 24 multi-channel biosensor and physical parameter inputs, complete the present network. Results show that bioelectric signals generated from a variety of freshwater species may be easily monitored in a similar manner and viewed as representative measures in community toxicity testing.