bluuebunny/crossref_metadata_2025_split huggingface dataset:
Waste-Water Treatment by Infiltration-Percolation on Sand: Results in Ben Sergao, Morocco
Authors: Guessab M. , Bize J. , Schwartzbrod J. , Mault A. , Morlot M. , Nivault N. , Schwartzbrod L. 
Published: May 2018

Waste-water from Ben Sergao (Morocco) is treated by a process using infiltration on sand which includes an anaerobic lagoon (1500 m3) in which waste-water has a retention time of 1.4 days followed by 5 infiltration basins (1500 m2 each). Each basin comprises by a 2 meter thick sand dune layer. The basins are drained at their base through a network of gravel-embedded drains. Three 350 m3 batches are performed daily. These are received in 3 separate basins. Each basin receives one batch a day during 3 days and is then left to rest for 2 days before carrying out a new cycle.
It has been estimated that the treatment induced a decrease of 99.93 % for the fecal coliforms and 99.98 % for the fecal streptococci. Concerning the parasitology, neither nematode eggs nor cestode eggs were found in treated sewage even though their number in raw waste-water could be estimated respectively to be 139 and 75 per liter.
As for physicochemical parameters, no significant difference appears between raw and treated sewage for K, P and conductivity, but there is a very significant increase of parameters NO2 and NO3 and a very important decrease of COD and total suspended matter after treatment.
This treatment process seems to be very well adapted for the treatment of sewage and the reuse of treated water in rural areas.
The Role of Colloid Interactions in Solid-Liquid Separation
Authors: Gregory John 
Published: May 2018

Forces between particles in water become especially important when the particles are in the colloidal size range (less than a few mm). To a first approximation inter-particle forces or colloid interactions are linearly dependent on particle size and they become stronger, relative to external forces, as particle size decreases. The separation of fine particles from water by processes such as coagulation, filtration and flotation can be crucially dependent on the manipulation of colloid interactions, usually to promote attachment of particles to each other or to surfaces.
The most important types of colloid interaction are briefly discussed. These include van der Waals forces, electrical interaction, hydration forces, hydrophobic interaction and effects associated with adsorbed polymers, such as steric repulsion and polymer bridging. These are all short-range interactions, which have little influence on the transport of particles but which can have a major effect on collision efficiencies and on the adhesion between particles. Some examples of solid-liquid separation processes in which colloid interactions are important are given.
Effects of Energy Input during Orthokinetic Aggregation on the Filterability of Generated Flocs
Authors: Bernhardt H. , Schell H. 
Published: May 2018

The implications of energy input (G value) and energy input time (t value) as well as the Gt value (Camp number) resulting from the orthokinetic particle aggregation as part of the adsorption coagulation with charge neutralization were investigated in the laboratory using a direct filtration test apparatus with a stirred reactor developed by the Wahnbach Reservoir Association. The tests were carried out at a constant particle concentration. The water was flocculated with 5 mg/l Fe3+ at pH 6. In compliance with literature references, an optimum removal of turbid matter by means of this direct filtration apparatus was achieved at G values of around 40 s−1, t values of 15-30 min and within a Gt range between 30,000-60,000 which corresponds to a GCt range of 60-120 according to Ives. Only in this range are the G values of 30-50 s−1 compatible with t values.
By comparison it was shown that these values are in reasonable agreement with the results of our tests implemented on a full-scale direct filtration with two successive stirred reactors. Optimum direct filtration conditions were found to occur within a G range of 30-60 s−1, at t values of 15-20 min and within a Gt range between 15,000-40,000. From this comparison it can be concluded that results of hydrodynamic investigations into orthokinetic aggregation, which were obtained with the described laboratory floc filtration test apparatus, may well be applied as guide values in full-scale direct filtration processes.
Advanced Treatment of Domestic Wastewater Using Sequencing Batch Reactor Activated Sludge Process
Authors: Imura M. , Suzuki E. , Kitao T. , Iwai S. 
Published: May 2018

In order to apply a sequencing batch reactor activated sludge process to small scale treatment facilities, various experiments were conducted by manufacturing an experimental apparatus made of a factory-produced FRP cylinder transverse tank (Ø 2,500mm).
Results of the verification test conducted for one year by leading the wastewater discharged from apartment houses into the experimental apparatus were as follows.
Excellent performance was achieved without any addition of carbon source, irrespective of the organic compound concentration and the temperature of raw wastewater.
Organic substances, nitrogen and phosphorus were removed simultaneously. Due to the automated operation format, stable performance was obtained with only periodic maintenance. Though water depth of the experimental plant was shallow, effective sedimentation of activated sludge was continued during the experimental period. Regarding the aerobic and anaerobic process, nitrification and denitrification occurred smoothly.
Potential Inaccuracy of Microbiological Counts from Routine Water Samples
Authors: Tillett Hilary E. 
Published: May 2018

The procedures for estimating numbers of organisms in water lead potentially to large inaccuracies. Routine microbiological sampling is an important component of monitoring source waters for drinking supplies and recreational waters. The results should be interpreted with awareness that each result is liable to two sorts of error, even when correct procedures are followed. Firstly, there is sampling error due to variation over time in microbial density at the place of sampling and, secondly, statistical inaccuracies introduced by laboratory methods. Some of the errors can be measured or estimated, especially those in the second category.
Pre-dilution of a sample, which is unavoidable with heavily contaminated waters, can affect results by chance. For example, if 10 organisms are found after a 100-fold dilution then the estimated count for the original sample would be 1000 with 95% confidence intervals of 482 - 1834. If a presumptive count is followed up with confirmatory procedures which involve sampling then another imprecision is introduced. For example, if a presumptive colony count of 25 is checked by confirmatory tests on only 5 colonies then, if 4 of the 5 confirm, the 95% confidence for the final count would be 8 - 24. Although statistical confidence intervals from the combination of such laboratory procedures could be calculated they have little practical value and could cause confusion. An investigator who receives a report in the format of an organism count which is qualified by a 95% confidence interval might wrongly attribute that range to the source water.
Variation at the water source is usually much greater than the errors introduced by proper laboratory procedures. This sample ‘error' can be estimated only by replicate sampling. All sources of error should be considered when the quality of the water is assessed. Decisions about whether the water meets a particular Standard might be better made, from a statistical point of view, by assessing multiple samples rather than concentrating on single counts from very small volumes of water.
Application of the PCR Technique to the Detection of Hepatitis a Virus in the Environment
Authors: Divizia M. , Morace G. , Gabrieli R. , Pisani G. , Panà A. 
Published: May 2018

Rapid, sensitive and specific teciiniques are needed to detect Hepatitis A virus in environmental samples. We have applied the method of Jansen et al. to concentrate river samples. In the analysis of 13 samples only two proved to be positive using the Elisa method (15.3%). Three samples were positive on cell culture (23%). The hybridization test resulted in 38.4% positive samples compared to the 67% obtained using the PCR method.
The PCR showed the highest sensibility when compared to the traditional methods (cell culture and Elisa) and the differences were statistically significant. The difference between hybridization test and PCR was not statistically significant.
The Investigation of Source Area Controls for the Treatment of Urban Stormwater Toxicants
Authors: Pitt R. , Lalor M. , Field R. , Brown M. 
Published: May 2018

This paper summarizes some of the information obtained during research projects sponsored and directed by the U.S. Environmental Protection Agency's (EPA) Storm and Combined Sewer Research Program. The first phase of the project investigated typical toxicant concentrations in stormwater, the origins of the toxicants, and rain and land-use factors that influenced the toxicant concentrations. All metals investigated were found in all samples, including most filtered sample fractions. Thirteen of the base-neutral and pesticide organic compounds were found in at least ten percent of the samples. The most frequently detected organics were 1,3-dichlorobenzene (maximum concentration of 120 µg/l) and fluoranthene (maximum concentration of 130 µg/l). Both of these compounds were detected in 23 percent of the samples.
The second phase of the project investigated the control of stormwater toxicants (measured using the Microtox® screening test) through treatment unit processes. The benefits of the treatment processes varied for different samples. However, some of the treatment processes consistently provided the greatest benefits. The most beneficial treatment tests included settling for at least 24 hours (generally 40-90% reductions), screening through at least 40 µm screens (20-70% reductions), and aeration and/or photo-degradation for at least 24 hours (up to 80% reductions).
The current project phase, which is just beginning, is testing a prototype treatment device that would be useful for controlling runoff from automobile service facilities, probably the most widespread and significant toxicant source in urban areas. This device is also intended for pretreatment before infiltration of source area runoff from other areas.
Impacts of Agricultural Nutrient Loading on Finnish Watercourses
Authors: Kauppi L. , Pietiläinen O.-P. , Knuuttila S. 
Published: May 2018

Eutrophication of lakes, rivers and coastal waters is the main environmental problem caused by agriculture in Finland. Water quality of most Finnish watercourses is good or excellent, but in the intensively cultivated region of southern and western Finland the turbidity of water as well as algal blooms are a common problem. Generally, phosphorus is the limiting nutrient for primary production in Finnish lakes, but in eutrophic lakes and coastal waters the role of nitrogen becomes more important.
Nitrogen from agriculture enters the watercourses mainly in dissolved form. By contrast, most phosphorus is transported in association with small particles. According to bioassays the algal availability of this paniculate P is very low. Therefore, the eutrophying effect of agriculture can be estimated on the basis of dissolved nutrients. In shallow lakes, typical in agricultural regions, the release of dissolved P from the bottom sediment often induces the development of N2-fixing blue- green algal blooms. In some cases the internal load may exceed the external load. For the recovery of such a lake the introduction of better agricultural practices in the drainage basin has to be coupled with in-lake measures.
Activated Carbon for Air Purification in New York City's Sewage Treatment Plants
Authors: Turk Amos , Mahmood Khizar , Mozaffari Jahangir 
Published: May 2018

Odors from New York City's sewage treatment plants are controlled by activated carbon housed in 44 large towers, each holding about 11 tons of carbon. The carbons are impregnated with NaOH or with KOH, or are unimpregnated but continuously injected with ammonia gas.
A study is now under way in our laboratory to monitor the progressive exhaustion of these carbon beds and to predict their useful lifetimes. The monitoring tests include a measure of the residual breakthrough capacity of the carbon for hydrogen sulfide, and an estimate of the remaining capacity for physical adsorption of other gases. For the caustic-impregnated carbons, the tests include a measure of the actual life-extension that can be realized by the retrofit of ammonia injection without interrupting the operation of the carbon vessels. A procedure to predict the results of in situ regeneration is described.
Viruses and Water: Problems, Detection, and Control
Authors: Dizer H. , Dürkop J. , Grohmann A. , Kopecka H. , López-Pila J. M. 
Published: May 2018

Secondary effluent of wastewater treatment plants contains a high number of viruses and other pathogens, which pose a health risk to the population, (especially when receiv ng waters are used for bathing and swimming, or for growing shellfish. In areas with a high density of population, where drinking water supply is dependent on surface waters and contaminated rivers are the primary source of drinking water, failure of the filtration or of the disinfection step, or of any other “barriers” supposed to warrant safe potable water, will increase the risk of health hazard for the consumer.
We have compared the efficiency of viral elimination in secondary effluent by flocculation, uv rradiation and membrane filtration taking naturally occurring, or additionally seeded f2 phages, as indicator for viruses. Flocculation decreased the number of phages present in secondary effluent by more than two logs. If combined with uv irradiation, the elimination reached five additional logs. Membrane filtration eliminated essentially all naturally occurring phages.
Improvement of the quality of surface waters calls for a refinement of detection methods for viruses. We have found that the polymerase chain reaction (PCR) might be used for detecting viruses in surface waters.
The Impact of Quaternary Paleoclimatic Change on the Carnivores of Israel
Authors: Dayan T. 
Published: May 2018

The Quaternary is a period of considerable climatic change. Climatic fluctuations have been subject to numerous studies based on various scientific disciplines (e.g., geology, sedimentology, palynology) that now enable us to reconstruct the paleoclimates of the last glacial period with some accuracy. In Israel such studies tell us of shifts in both ambient temperatures and in humidity. These paleoclimatic changes had paleoecological effect. Studying the paleoecology of the fauna of Israel may give us a key to understanding the effects of past climatic shifts, and to predicting the impact of future climatic change in this country.
Here I follow changes in distribution, diversity, and morphology of carnivores throughout the last glacial of Israel. Size increase and shifts in distribution occurred in some carnivore species, and overall there is a strong correlation between humidity and species diversity. Carnivores typically exhibit wide geographic distributions, and wide environmental tolerance. Therefore paleoecological effects of paleoclimatic shifts in carnivores may indicate similar effects in other, less euryecious, terrestrial mammals.
Modelling Sediment Transport and Sediment Quality in a Shallow Dutch Lake (Lake Ketel)
Authors: Blom G. , Toet C. 
Published: May 2018

Lake Ketel is a shallow Dutch lake, part of the river Rhine delta, with a surface area of 38 km2. Between 1960 and 1980 15×106 m3 contaminated sediment accumulated in the lake. After 1980 the contaminant load started to decrease. A common hypothesis was that the relatively clean solids supplied now, would slowly cover the contaminated sediment layer. Research indicated however a serious erosion of old and polluted bottom sediments.
To quantify resuspension and sedimentation fluxes the sediment transport model STRESS-2d has been applied. Simulation results show a net sedimentation of 300×l06 kg year−1, but an erosion of old and polluted sediment of 350×106 kg year−1. In large areas in the lake net sedimentation is only a few millimetres a year, while high resuspension and sedimentation fluxes lead to an intensive interaction between sediment and water.
Spatial variability in resuspension and sedimentation fluxes will lead to spatial gradients in the response of the bottom sediment to the reduced contaminant load. Based on the simulated resuspension and sedimentation fluxes, a simple model for the Cd concentration in the bottom sediment has been developed. Simulation results show a relatively fast decrease of the Cd concentration in the upper sediment layer areas with high net sedimentation and/or (brute) resuspension and sedimentation fluxes.
Remediation of PCB-Contaminated Sediments in Lake Järns Jon, Emän River System, Sweden
Authors: Gullbring P. , Hammar T. 
Published: May 2018

Järnsjön, a lake in the Swedish river Emån, contains approx. 400 kg of PCB which is slowly leaching out from the sediments. An analysis program has shown that the Järnsjön sediments are the primary source for ongoing discharge of PCB to the river. Based on the current yearly discharge of 7 kg PCB, the sediments will cause problems during several decades.
The Emän river is classified as a resource of national importance. Remediation of Järnsjön is necessary if continued damage is to be avoided. However, remedial activities in lake Järnsjön can lead to an additional load on Emån. Restrictions on such releases during remediation of Järnsjön will therefore be stringently applied.
The feasibility of remediating Järnsjön, has been examined in a number of studies carried out by the Swedish EPA together with different universities, institutes and consulting companies. A primary alternative has been selected. This alternative includes vacuum dredging within a protective barrier of silt screens. Dredged material will be dewatered and disposed of in a special landfill. This remedial action is estimated to cost appr. 40 million Swedish kronor. (6 - 8 million dollars). The remediation has started and will be concluded in 1994.
Remediation Work for Mercury Contaminated Bay – Experiences of Minamata Bay Project, Japan
Authors: Hosokawa Y. 
Published: May 2018

The Minamata Bay remedial project, which commenced in 1977, was completed in 1990.1.5 million m3 of mercury contaminated sediment were treated by careful dredging and confined reclamation. A contaminated area of 2 million m2 in Minimata Bay was decontaminated.
During this large project, we have faced several technical problems. Some of the experiences are expected to be useful for planning remedial works of other areas. The following topics are presented with technical details:a.initial distribution of mercury in the bottom sediment,b.monitoring system design and monitoring committee,c.dredging work with specially designed vessels,d.sand capping over reclaimed sediment for confinement,e.residual mercury after dredging.
Economic considerations were important, but we gave a higher priority to safety. For the remediation, we had to usei every possible technique in order to minimize secondary pollution.
Pollution Measurement Accuracy Using Real Time Sensors and Wastewater Samples Analysis
Authors: Ruban G. , Marchandise P. , Scrivener O. 
Published: May 2018

This paper deals with a comparison of the pollution measurement accuracy between real time pollution sensors (especially Suspended Solids - S.S.- determination by turbidimetry) and standard samples analysis on raw wastewaters. The two methods are used in commonly favourable conditions.
Considering separate measurement errors, the S.S. random errors of the two methods are in the same order of magnitude (about ± 25% for a 90% confidence interval), but sampler/analyses lead to a systematic underevaluation of about 17%. These rather high figures for the sampling/analyses method are due to the cumulation of samples compounding and preservation errors.
The determination of the samples collection error when estimating pollution loads is based on a set of 12 rainfall events registered during a 5 month study on a combined sewer overflow. Due to an optimized sampling strategy, the use of a 24 bottle sampler shows an average S.S. load underevaluation of only 5%, compared with the continuous estimation of the pollution sensor considered as a reference.
Real time pollution sensors can, therefore, be considered as convenient systems for field experiments where particulate pollution is of special interest, which is the case for runoff waters. Besides which, they are particularly suitable for the control and automation of sanitary transport and treatment equipment, being easily integrated into computerized systems.
Biological Early Warning Systems for Toxicity Based on Activated Sludge Respirometry
Authors: Temmink H. , Vanrolleghem P. , Klapwijk A. , Verstraete W. 
Published: May 2018

The proper operation of the activated sludge process is endangered by toxic spills in the wastewater that has to be treated. Therefore there is a need for so called biological early warning systems (BEWSs) that can detect toxicity for the activated sludge process and allow operators to take protective actions.
Two independently developed BEWSs are described and evaluated. Both systems are based on the on-line measurement of the respiration rate of activated sludge taken from the plant to be protected. Their practical implementation however is different with respect to the way the suspicious wastewater is brought into contact with the sludge. It is illustrated what the consequences of the design choices are with respect to the sensitivity, the response time and the positioning at the treatment plant of these BEWSs.
MONTE CARLO MODELING OF WATER AND SEDIMENT CONTAMINATION BY TOXIC METALS AT THE NORTH AVENUE DAM, MILWAUKEE, WI, USA
Authors: Novotny Vladimir , Feizhou Lai , Wawrzyn William G. 
Published: May 2018

A deterministic water - sediment quality model was developed with a Monte Carlo interface and input generation. The model was used to simulate water and sediment (total and dissolved-pore water) quality of a reach of Milwaukee River that includes an urban impoundment. The sediments in the impoundments are contaminated by toxic metals and other priority pollutants.
The sediment - water quality model was composed of three sequential segments each represented by three systems: water, upper sediment and lower sediment layers. The mass balance of the sediment contaminants was strongly affected by the direction of the groundwater fluxes through the sediments. Steady state was assumed for the water column and the upper sediment layer while a dynamic mass balance model was used for the lower sediment layer.
The inputs of the Monte Carlo simulation were ten years long time-series of upstream flows and Combined Sewer Overflow (CSO) discharges with corresponding Monte Carlo generated concentrations. The model calculated output concentrations which were statistically similar to the probability distribution of measured concentrations.