bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nitrogen Transformations and Removal in Waste Stabilization Ponds in Portugal: Seasonal Variations
Authors: Santos M. C. R. , Oliveira J. F. S. 
Published: May 2018

Nitrogen transformations that can occur in WSP depend on pond and waste characteristics and are also influenced by climatic factors, like temperature and precipitation. Experiments described have been carried out using a system of three ponds in series: anaerobic, facultative and maturation, treating domestic sewage. In this paper we aim to identify the processes that might contribute to N transformations in each pond and the seasonal variations in the removal of nitrogen and its bioconversion throughout the year.
Results have proved that there was an important organic N removal in the anaerobic pond, mainly due to mineralisation and not exclusively by sedimentation.
Some of the processes of N transformation observed in the ponds were more strongly influenced by weather conditions than others. In some cases, the increase of biological activity that was induced by the increase in air temperature, was masked by reduced precipitation which produced less diluted treated effluents. These climatic factors can explain some of the variations observed along the year, in what concerns nitrogen compounds concentrations.
Microorganism Removal in Waste Stabilization Ponds in Portugal
Authors: do Nascimento M Jenny 
Published: May 2018

This study has evaluated the removal of traditional biological indicators of faecal pollution and two new indicators: Pseudomonasaeruginosa and Clostridiumperfringens in waste stabilization ponds which were installed at the waste treatment plant of Loures, at Frielas, near Lisbon.
The removal efficiency for indicator organisms was 10/100 ml in the anaerobic pond A1, except for one of them, and less in A2. In facultative ponds the removal was 10/100 ml while in maturation pond M2 the removal efficiency was higher for traditional indicators than for the new indicators; in pond Ml the removal was less than in M2.
Effects of Maturation on the Characteristics of Wastewater Stabilization Pond Sludges
Authors: Carré J. , Baron D. 
Published: May 2018

The physical-chemical characteristics, (pH, Eh, S2−, TOC, NH4+, particulate Kjeldahl nitrogen (PKN), total phosphorus (TP) and PO43−.) of the sludge accumulated in the first of a series of wastewater stabilization ponds nave been studied in two vertical profiles in order to characterize the effects of the maturation of the sludge. The effects on the concentration of faecal indicator organisms and salmonella have also been determined.
The maturation leads to an increased density of the sludge and to the removal of about 80% of the TOC, 70% of PN and of 75% of TP initially present in the fresh sludge.
The concentrations of sulfate reducing bacteria do not change and those of the total coliforms, the faecal coliforms and the faecal streptococci are only moderately modified, as the maximum decrease is 4 log. Salmonellae only are found in the superficial sediment layer, which might indicate their rapid inactivation.
Deep Wastewater Reservoirs in Israel – I: Limnological Changes following Self-Purification
Authors: Dor Inka , Kalinsky Iris , Eren Jahob , Dimentman Chanan 
Published: May 2018

Ma'ale Kishon, one of the largest reservoirs storing wastewater for irrigation in Israel, has surface area of 1.3 km2, depth of 9 m and volume of 12 million m3. Secondary effluent enters the northern basin and after a mean retention period of 6 weeks, flows into the southern one. Due to this two basins structure, changes taking place during the water storage can be detected. The differences between the two basins were quantitatively studied by an interdisciplinary team.
The sanitary, physico-chemical and biological variables indicated an improvement in water quality, leading to an increased ecosystem stability and a safer environmental performance. These results suggest that deep reservoirs of the type here described serving for wastewater disposal and reuse may have a wide application also in other countries having warm, subtropical climates.
High Load Process Using Yeasts for Vinasses of Beet Molasses Treatment
Authors: Malnou D. , Huyard A. , Faup G. M. 
Published: May 2018

Bulky plants are required to treat industrial effluents using conventional processes (settlement tanks, activated sludge, etc.). New techniques are being sought to reduce the size of the plants.
The use of microorganisms, such as yeasts, in aerated reactors makes it possible to process effluents with very high volumetric loads and to produce a valorizable biomass.
Despite their high salinity and COD concentration, yeasts can be used to process sugarbeet molasses liquors with volumetric load exceeding 80 kg COD.m−3.d−1, removing 70 % of the COD.
The improvement in the quality of the biomass produced and the design of new types of reactor will allow this high-performance process to be developed into an interesting alternative method of treating concentrated industrial effluents.
Design Considerations for a Nitrification-Denitrification Process Using Two Fixed-Bed Reactors in Series
Authors: Jimenez B. , Capdeville B. , Roques H. , Faup G. M. 
Published: May 2018

This paper concerns design considerations (kinetics and hydraulic criteria) for a biological nitrification-denitrification attached culture process for sewage treatment.
The treatment system is composed of two submerged filters. The first one, an anoxic reactor, denitrifies and retains wastewater suspended solids. The second one oxidizes organic carbon and ammonia nitrogen.
It was found that the main parameter for the system is the recycle ratio since it sets the real hydraulic detention time in reactors and determines the quantity of nitrogen available to the denitrification process.
Coagulation of Two Different Kinds of Surface Water before Inlet into Lakes to Improve the Self-Purification Process
Authors: van der Veen C. , Graveland A. , Kats W. 
Published: May 2018

Part of the drinking water demands of the city of Amsterdam and the surrounding district are met by abstraction from nearby Lake Loenderveen that is fed by two different kinds of surface water. The lake itself is subject to rainfall, evaporation and seepage. It acts partly as a stockpiling reservoir (about 2 weeks) and partly as a self-purifying medium (retention time about 100 days).
The design and management of the lake are such that a high degree of mixing of the inflowing water is obtained and an almost constant water quality, which greatly facilitates subsequent treatment to obtain high quality drinking water.
To combat eutrophication the nutrient-containing water that enters the lake is dephosphated. After a number of years working with an experimental and simplified method in the lake itself, a highly efficient new coagulation and settling plant was constructed. This has been in operation since 1984. The improvements in the quality of the lake water are discussed in this paper. In addition to a considerable reduction in the phosphate content (and that of other nutrients), improvements were registered in a number of other water quality parameters (DOC, heavy metals, colour c.a.).
A similar coagulation and settling system is also used to treat one kind of surface water that is fed into the adjacent Loosdrecht Lakes during dry summer spells.
These lakes are of great environmental importance; they are also unique features of the landscape. Pretreatment of the water that flows into the lakes has a substantial effect on the water quality. A monitoring system has been set up to check the resulting improvement.
Summary of Results from the Swedish Project ‘Environment/Cellulose'
Authors: Södergren A. , Bengtsson B.-E. , Jonsson P. , Lagergren S. , Larson Å , Olsson M. , Renberg L. 
Published: May 2018

The biological effects of effluents from pulp industries, especially from bleaching processes, on aquatic ecosystems were studied in a joint biological/chemical project field consisting of several sub-projects. The principal study was devoted to the effects of biologically active chlorinated organic compounds.
A receiving body of water for pulp bleach plant effluents at the Gulf of Bothnia was chosen for the three year study. Near the effluent outlet the fish biomass was low, and the species composition of the fish community had changed. Perch (Perca fluviatilis L.) exhibited reduced reproduction and disturbed physiology in all parts of the receiving body of water. The effluent also affected the diversity, biomass and distribution of invertebrates and plants. To further study the effects, fish and benthic-living organisms were exposed in the laboratory to sediment from the receiving water and to various mixtures of bleach plant effluents. The level of extractable organic chlorine (EOC1) of the perch decreased along a gradient from the effluent outlet towards the open sea. In sediment outside the Swedish coast, the level of EOC1 and the occurrence of compounds related to bleach mill effluents indicated a distribution of such substances over large areas.
Control of the Phosphorus Level of Effluent in the Treatment of Forest Industry Waste Waters
Authors: Väänänen P. 
Published: May 2018

Pulp and paper mill wastewaters are nutrient deficient, BOD5:N:P may be as low as 100:1:0.2. Now that purification requirements have been tightened, the activated sludge process seems to be most commonly used treatment method. The conventional activated sludge process requires BOD:P ratios of 100 to 0.6 resulting in a need for P addition and hence in a possible increase in the P-level of the effluent.
In Finland and also in some other areas phosphorus removal is of great importance in the prevention of eutrophication of watercourses. There are several methods to control phosphorus level, such as biological phosphorus removal, running of the process under starvation of phosphorus, tertiary (chemical) treatment and simultaneous precipitation of phosphorus. This paper lists possible treatment methods and presents more closely chemical treatment using simultaneous precipitation by ferrous sulphate. The results are based on both pilot and full-scale experiments in two kraft pulp mills.
The study showed that phosphorus concentration can be reduced to a level of 1.2 mg/l (tot.P) by adding ferrous sulphate to the aeration basin in activated sludge treatment of kraft pulp mill wastewaters. Ferrous sulphate has, also, a slight positive effect on the sludge properties e.g. sludge settleability.
Treatment and Characterization of Biological Sludges from the Pulp and Paper Industry
Authors: Kyllönen H. L. , Lappi M. K. , Thun R. T. , Mustranta A. H. 
Published: May 2018

A research project on characterization and treatment of sludges from the pulp and paper industry was initiated at the Technical Research Centre of Finland (VTT) at the beginning of 1986. The research is included in a research programme on non-waste technology. The aim of the work is to develop optimal treatment processes for pulp and paper mill sludges.
The first experimental phase, currently underway, is focused on investigations of various ways of releasing bound water from the sludge, with particular emphasis on developing correlations between measurable sludge properties and dewatering behaviour. Activated sludges of different origin have been subjected to various chemical, thermal and enzymatic treatments. The effects of these conditioning treatments on the properties of the sludges have been characterized by different analytical methods, for example, by measuring changes in the specific resistance to filtration, the amount of water bound in different ways, the particle size distribution, and the chemical composition of the sludges. Results of these experiments are discussed.
The interpretation of the effects of the treatment methods studied was hampered by deviating properties of sludges. A treatment effective for one sludge under certain conditions did not have a similar effect on the dewatering properties of some other sludge. Thermal treatment of sludges proved to be the most effective method for breaking water binding, although the most influential factor could not be identified. Ultrasonic treatment had a clear effect on the particle size distribution and settling of the sludges, but not on dewaterability, and proved to be closely related to the sludge concerned. The enzymes tested had no significant effect on the dewatering characteristics of the sludges. The results obtained so far will be used for designing an optimal sludge treatment process in future work.
The Potential of Free-Living Ground Water Bacteria to Degrade Aromatic Hydrocarbons and Heterocyclic Compounds
Authors: Arvin E. , Jensen B. , Aamand J. , Jørgensen C. 
Published: May 2018

This study has documented that a considerable degradation potential related to aromatic hydrocarbons and aromatic nitrogen-, sulphur- and oxygen- containing compounds is associated with the free-living ground water bacteria. All studies were performed under aerobic conditions and with surplus of nitrogen and phosphorus.
After a lag period, which differs considerably between locations upstream and downstream of hydrocarbon spills, the free-living bacteria are able to degrade the hydrocarbons to concentrations less than 1 µg/l. The bacteria from one site were able to degrade naphthalene according to a zero order reaction even at 1 µg/l.
Preliminary experiments indicate that the free-living bacteria may have a relatively high activity compared to the attached bacteria when compared on the basis of the same total bacteria numbers.
The hypothesis is put forward that, although the attached biomass concentration in the aquifer may be much higher than the free-living biomass, the latter is still very important for the degradation capability if the attached bacteria are fixed in the fine soil fractions (silt, etc), the reason being that the flow of water, and with this the flux of substrate, is relatively small to the attached bacteria due to low hydraulic conductivity in the fine soil fractions.
The Influence of Blade Height on the Removal of Sludge from Activated Sludge Settling Tanks
Authors: Billmeier Ernst 
Published: May 2018

This paper describes the factors which influence the quantity of sludge settling on the floor of circular tanks and methods for determining this. The dimensions of the sludge thickening and collection zones are considered and the required sludge removal capacity is evaluated. Methods for the design of the scrapers necessary are given with particular reference to the height of the blades.
An example of the use of the design procedure is given.
Field and Experimental Study of the Bioaccumulation of Some Trace Metals in a Coastal Food Chain: Seston, Oyster (Crassostrea Gigas), Drill (Ocenebra Erinacea)
Authors: Amiard-Triquet C. , Amiard J. C. , Berthet B. , Metayer C. 
Published: May 2018

From March 1982 to May 1984, monthly sampling has been carried out in a comparatively un-polluted coastal area (bay of Bourgneuf, France), allowing the determination of Cd, Cu, Pb and Zn concentrations in water and in the different links of the studied food chain. Except for Pb, the higher the metal level, the higher the trophic level. In order to determine if this situation results from a real biomagnification in the food chain or from specific abilities to concentrate trace metals, oysters and drills were exposed to metals frcm different sources.
Young oysters were exposed for 4 weeks, simultaneously to Cu and Pb, through seawater and/or food. The metals were analyzed in phytoplankton in order to evaluate the daily food supply of metals to oysters. The body burden of Cu and Pb in oysters and their concentrations were evaluated after 12, 20 and 28 days of exposure. In controls and oysters contaminated via food the body burden of Pb decreased during the experiment. This indicates that the quantity of Pb eliminated was higher than the input of this metal. Moreover, the direct uptake from water led to body burdens approximately 100 times higher than those reached after contaminated food ingestion. Contaminated seawater + food did not induce any significant additional increase. For Cu, the body burden increased during the experiment in controls as well as in oysters fed with contaminated phytoplankton. This means that the quantity of Cu eliminated is lower than the input of this metal. However, the body burdens induced by exposure to contaminated seawater or seawater + food are at least ten times higher than those registered in oysters exposed via phytoplanktonic food. This result, as well as the high concentration factor of Cu in C.gigas (approximately ten times higher than in phytoplankton) emphasize the ability of oysters to concentrate Cu. This could explain the increase of Cu concentration in increasing trophic levels observed in the field study but the accumulation of Cu from food is significant and could play a role in chronic exposures.
Drills were placed for 6 weeks in plastic net bags containing no food or food with different levels of metals. No significant differences were observed between the levels of Cd, Cu and Zn in controls and in drills of the three groups, indicating that these levels do not depend on the food.
Microbiological Quality Control in the Provision of Safe Drinking Water*
Authors: Hayes C. R. 
Published: May 2018

The legislation from the European Commission and various other guidelines are discussed in the context of microbiological standards for drinking water. Difficulties in applying these standards are identified and reference is given to the quality control procedures adopted by Anglian Water. Pressures to achieve other drinking water standards, especially trihalomethanes, and the possible need to achieve higher microbiological quality objectives than those regulated currently, could lead to major changes in UK treatment practice.
* The full version of this article will appear in Water Science and Technology, 21(6/7), 559-566 (1989).
Development of Dialog System Model for Eutrophication Control between Discharging River Basin and Receiving Water Body – Case Study of Lake Sagami (Japan)
Authors: Suzuki M. , Chihara K. , Okada M. , Kawashima H. , Hoshino S. 
Published: May 2018

A computer program based on expert system software was developed and proposed as a prototype model for water management to control eutrophication problems in receiving water bodies (Suzuki etal., 1988). The system has several expert functions: 1. data input and estimation of pollution load generated and discharged in the river watershed; 2. estimation of pollution load run-off entering rivers; 3. estimation of water quality of receiving water bodies, such as lakes; and 4. assisting man-machine dialog operation.
The program can be used with MS-DOS BASIC and assembler in a 16 bit personal computer. Five spread sheets are utilized in calculation and summation of the pollutant load, using multi-windows. Partial differential equations for an ecological model for simulation of self-purification in shallow rivers and simulation of seasonal variations of water quality in a lake were converted to computer programs and included in the expert system. The simulated results of water quality are shown on the monitor graphically.
In this study, the expert system thus developed was used to estimate the present state of one typical polluted river basin. The river was the Katsura, which flows into Lake Sagami, a lake dammed for water supply. Data which had been actually measured were compared with the simulated water quality data, and good agreement was found.
This type of expert system is expected to be useful for water management of a closed water body.
Effects of Thermal Pretreatment of Sewage Sludge on Anaerobic Digestion
Authors: Pinnekamp J. 
Published: May 2018

The study examines the constraints on thermal pretreatment of sludge at temperatures in excess of 100 °C and its effects on subsequent anaerobic digestion. The table below summarizes the maximum measured increase rates and the corresponding optimum pretreatment temperatures as a function of the type of sludge tested. The influence of the sludge type is considerable.Sludge TypeGas Yield without/with PretreatmentMaximum increase RateOptimum Pretreatment Temperaturel/kg VSinfl%°CDigested Sludge60.4223.0+ 269.2180Excess Sludge SLR = 0.03124.7278.1+ 123.0135Excess Sludge SLR = 0.15314.7546.7+ 73.7170Excess Sludge SLR = 2.00234.7334.2+ 42.4135Primary Sludge259.0326.6+ 20.3170Excess Sludge SLR = 0.60596.8600.0+ 0.5135
Calculation of detailed energy balances for various sludge treatment systems with and without thermal pretreatment revealed a clear economic advantage for thermal pretreatment. The excess heat for an overall system composed of thermal pretreatment, anaerobic stabilisation and digester-gas electricity generation is significantly higher than that for a system without pretreatment. Sludge pasteurisation represents an additional advantage of thermal pretreatment.
In general, it may be stated that, provided certain conditions are satisfied, thermal pretreatment of sewage sludge prior to anaerobic stabilisation can positively affect the energy balance of the treatment plant.
Experimental and Theoretical Studies of Sulfide Generation in Sewerage Systems
Authors: Holder G. A. , Van Oorschot R. , Hauser J. 
Published: May 2018

The measurement of sulfide generation rates from sewer slimes using a rotating-drum reactor is described. The practical utility of this procedure for assessing the contribution to sulfide production which arises from the admission of industrial wastes into domestic sewage is demonstrated. The use of the reactor for more theoretical purposes such as the determination of the zero-order rate constant for a particular sewage is also described.
The effect of flow velocity on sulfide generation rate was investigated by pumping sewage at controlled rates through a ‘model' sewer which ‘flowed full'. Under turbulent flow conditions (Re&gt;4000) the rate of sulfide production (expressed as a mass flux g m−2day−1) was relatively high and the effect of flow rate on the rate of production was positive but small. In the laminar region (Re&lt;2100) the situation was reversed i.e. the sulfide mass flux was relatively low but the effect of flow rate on sulfide production was relatively large.
Theoretical studies of sulfide generation are outlined. The zero order rate constant, determined using the rotating drum reactor, was utilised to predict sulfide generation rates in the model sewer. Agreement between experiment and prediction was satisfactory for conditions of turbulent flow. For laminar flow the agreement was less satisfactory. However the predictions for laminar flow were qualitatively correct in as much that a significant drop in sulfide generation rate was observed on moving into the laminar flow region.
The results of the studies show that it is possible to develop a predictive design procedure for sulfide production based on established engineering principles rather than relying on empirical correlations.