bluuebunny/crossref_metadata_2025 huggingface dataset:
Modelling the Consequence of Cooling Water Discharge from the “Vendsyssel” Power Plant
Authors: Malmgren-Hansen Anders , Dahl-Madsen K I
Published: May 2018

Discharge of cooling water from power plants has various effects on the ecosystem in coastal areas. The effect on primary production due to the rise in temperature in the outlet area and the decimation of zooplankton organisms passing through the cooling system of the power plant can be calculated by means of mathematical models.

Calculations of the consequences of a considerable increase in cooling water discharge from the “Vendsyssel” power plant are presented.

The decimation of zooplankton is calculated by means of a combined 2-dimensional hydraulic and zooplankton-growth model.

Calculations of the effects on primary production are carried out by use of a combined 1-dimensional hydraulic and eutrophication model.
Transport of Airborne Mercury Emitted by Coal Burning into Aquatic Systems
Authors: Brosset Cyrill
Published: May 2018

Concentrations of watersoluble and insoluble mercury compounds in air, precipitation and smoke from coal combustion have been measured.

It has been found that in western Sweden 10-20% of airborne mercury is in an oxidised watersoluble form. The corresponding figure from one boiler is ~70%.
Possible Biological Mechanism of Phosphorus Removal
Authors: Buchan L
Published: May 2018

This paper describes an investigation which was conducted to determine the location and nature of accumulated phosphorus in several enhanced phosphorus-removing activated sludges. Phosphorus accumulations were located by electron microscopy combined with the energy dispersive analysis of X-rays. In all the sludges phosphorus accumulations were located in a specific morphological cell-type, which was also the predominant organism in the sludges. These cells typically occurred in large cell-clusters and were identified as Acinetobacter spp. Quantitative analyses indicated that the intracellular polyphosphate granules contained in excess of 25 % (m/m) phosphorus and a Ca:P ratio between 0,15-0,36. These cells released o-P during anaerobiosis. Factors leading to accumulation were examined and it was found that accumulation was possible under continuous aerobic culture and was enhanced by unidentified fermentation products of raw sewage; these products also induced the accumulation of intracel1ular carbon reserves by the cells. It was concluded that enhanced biological phosphorus removal by activated sludge is dependent on the enrichment of certain Acinetobacter spp in the system.
Full Scale Experiences with the Phostrip Process
Authors: Peirano Lawrence E , Henderson Douglas B , Gonzales John G M , Davis Eugene F
Published: May 2018

The PhoStrip process is a biological-chemical process which removes phosphorus from wastewater.

This article presents descriptions of the PhoStrip process, a plant-scale test of the process, the design of a 152,000 m3/d PhoStrip facility, and the start-up and initial full scale operation of the PhoStrip facility, all in association with the expansion of the Reno-Sparks Joint Water Pollution Control Plant in Nevada, USA.

The PhoStrip process has demonstrated the capability of removing phosphorus to effluent levels of less than 0.5 mg/l at operating costs much less than operating costs associated with conventional chemical processes.
Off-Flavours in Aquatic Ecosystems – An Introduction
Authors: Persson Per-Edvin
Published: May 2018

The significance of off-flavours in water and fisheries management is briefly discussed, as are guidelines for future research. In order to elucidate the sources and causes of off-flavours in natural waters, an integration of sensory, chemical and biological research is needed. Sensory characterization of off-flavours often involves taste and odour threshold measurements. Current techniques at water works are critically discussed. The need for a more comprehensive approach, where sensory response is related to stimulus intensity over a large range of magnitudes, is stressed. The use of consumer panels in sensory assessment of water quality is advocated. Sensory methods are useful screening methods. Chemical analyses should be related to the sensory characteristics of the compounds analyzed. Recent research on biogenic off-flavours in natural waters have indicated that they are more, complex than originally conceived. Criteria for establishing the odour production by organisms are presented. Compilations of scientifically proved taste and odour producing algae and micro-organisms may be useful, but more research is needed on the reasons for variability of their odour production. The development of relevant abatement techniques depends on a more complete understanding of the etiology of off-flavours in natural waters.
Volatile Odorous Excretion Products of Different Strains of Synechococcus (Cyanobacteria)
Authors: Henatsch J J , Jüttner F
Published: May 2018

Volatile compounds excreted by different strains of Synechococcus have been studied. The lipophilic components were extracted from the cell-free culture medium by resin sorption techniques. XAD-20 and Tenax GC were used to concentrate less volatile excretion products for GC/MS identification. Major compounds released were 6-methylhept-5-en-2-one, dihydroactinidiolide and tetrahydrogeranyl acetone suggesting that the formation of excretion products in Synechococcus is closely connected to the metabolism of lipids and carotenoids.
Mathematical Modelling of the Anaerobic Digestion Process: Regulatory Mechanisms for the Formation of Short-Chain Volatile Acids from Glucose
Authors: Mosey F E
Published: May 2018

A model of the anaerobic digestion process is presented which attempts to explain the complex patterns of volatile acid production in the anaerobic digestion process. The hydrogen-utilising methane bacteria are identified as the controlling organisms for the redox potential of the process. Mathematical expressions for the regulation of metabolism by hydrogen are derived from the known redox potential of the NAD/NADH couple.
Attached versus Suspended Growth Anaerobic Reactors: Response to Toxic Substances
Authors: Parkin G F , Speece R E
Published: May 2018

Anaerobic methane fermentation has significant potential for treatment of industrial wastewaters. Application of the process has been limited, due in part to the belief that the process cannot tolerate chronic and transient toxicity inherent in many industrial wastewaters. Experiments with cyanide, chloroform, formaldehyde, ammonium, nickel and sulfide have shown that the methanogens have the ability to recover from and acclimate to relatively high concentrations of toxicants. The key is proper attention to solids retention time. Of the two general reactor types used in biological waste treatment, attached growth systems offer two major potential advantages over suspended growth systems for treating wastewaters containing toxicants: (1) higher inherent solids retention times at relatively low hydraulic retention times and (2) the potential for a quasi plug-flow hydraulic regime that allows rapid elution of toxicants. For transient toxicity, the ability of a plug-flow, attached growth system to rapidly elute toxicants resulted in dramatically reduced down times when compared to a complete-mix, suspended growth system. For chronic toxicity, the solids retention capability of attached growth systems allows for acclimation to occur prior to washout of active biomass. Effluent recycle to plug-flow, attached growth systems should allow for more gradual exposure to chronic toxicity, thus maximizing acclimation potential.
Fluidized Bed Biofilm Reactor (FBBR)Kinetics – A Rational Design and Optimization Approach
Authors: Shieh Wen K , Mulcahy Leo T
Published: May 2018

A mathematical model is presented for an intrinsic zero order, completely mixed fLuidized bed biofilm reactor(FBBR). Intrabiofilm mass transfer effects are considered. A modified Thiele modulus(ϕm) is defined to relate substrate conversion rate to intrabiofilm mass transfer rate through use of an effectiveness factor(η). For ϕm− < 1.15, intrabiofilm mass transfer is insignificant and intrinsic zero order kinetics is observed. For ϕm > 1.15, the FBBR substrate conversion rate is mass transfer limited and 0.45 order kinetics is observed.

It is demonstrated via the FBBR model that media size and density and biofilm thickness are the most significant design parameters affecting FBBR performance. Selection of these parameters can be optimized through use of the equations presented herein. In addition, the effect of other important design parameters such as recycle rate and superficial upflow velocity on reactor performance can be assessed using the FBBR model outlined here.
Effect of Media Design on the Performance of Fixed-Bed Anaerobic Reactors
Authors: Young James C , Dahab Mohamed F
Published: May 2018

Investigations were conducted using four different media in large laboratory-scale anaerobic filters to show the importance of media type, size, and shape on waste treatment performance. These tests have shown that a majority of the waste treatment takes place in the lower filter heights and is associated to a large extent with the biological solids that are held loosely within the interstitial void spaces within the media matrix. Therefore, the ability of the media to retain high concentrations of biological solids either as suspended growth or by attachment to the media surfaces is an important design consideration. This solids retention characteristic seems to be as closely related to media shape and void size as to unit surface area. Media selected for full-scale anaerobic filters should permit withdrawal of biological solids to prevent accumulations that can contribute to short-circuiting and loss of treatment efficiency.
Sludge Thickening Prior to Anaerobic Digestion
Authors: Kapp H
Published: May 2018

In the Federal Republic of Germany the average solids content in digested sludges is about 3%. Increasing the solids content to 6-8% by pre-dewatering would mean that the sludge volume would be reduced to 40-50%. For the same retention period the volume of new digesters will be reduced and the necessary energy for heating decreased. Overloaded sludge treatment plants can be upgraded, as digestion time becomes longer and gas production increases.

As pre-dewatering machines, first of all decanting centrifuges and screens can be recommended. The addition of coagulant aids is necessary to some extent.

In the case of two practical examples, the operating parameters of raw sludge thickening as well as the economic advantages of the operating procedure are shown.
Operating Experiences at Low Solids Retention Time
Authors: Wilson T E , Ambrose W A , Buhr H O
Published: May 2018

Five full scale activated sludge plants have been operated at low solids retention time (SRT, monthly averages as low as 0.8 days) and mixed liquor suspended solids (MLSS, monthly averages as low as 500 mg/l) values for 2 to 3 years. Operating results for this period are compared to 3 to 3-1/2 years of operation at conventional, higher, SRT and MLSS values. The data show that the lower SRT operation provided better effluent quality, typically achieving less than 15 mg/l of BOD5 or suspended solids, while not significantly increasing either the total (dry) sludge production or the sludge volume index (SVI). These data indicate that plants can be built and operated using significantly smaller tankage than conventionally accepted.
The Eastern Scheldt Project
Authors: Knoester M , Visser J , Bannink B A , Colijn C J , Broeders W P A
Published: May 2018

In the planning of the Delta-works, carried out in the Southwestern Netherlands, the Eastern Scheldt was the largest and therefore last tidal basin to be fully closed mainly to protect the area from floods. Increased recognition for the natural value of estuaries and a strong lobby from nature conservationists and shellfish producers led to a reconsideration of original plans, confirmed by a series of governmental decisions. Per consequence execution of the present plans will result in a storm-surge barrier at the entrance of the tidal basin together with two partitioning dams, separating the (reduced) tidal Eastern Scheldt from a new freshwater lake. Attention is paid to the present values in the Eastern Scheldt and briefly to changes involved by the project. The decisionmaking process is described and discussed: In the course of the project the majority of decisions taken were prepared by teams of ecologists, civil engineers, hydrologists and financial experts using policy-analysis methods. For guidance of developments in the influenced area the local government accepted a policy plan, in which human uses are regulated. Operations of the barrier are designed such that safety from flooding is guaranteed, while adverse effects for the tidal ecosystems are minimized.
Environmental Consequences of a Large Scale Coastal Engineering Project on Aspects of Mussel Cultivation in the Eastern Scheldt
Authors: Misdorp R , Kohsiek L H M , Steyaert F H I M , Dijkema R
Published: May 2018

The rewatering location in the Eastern Scheldt at Yerseke has an important function for the Dutch mussel culture, safeguarding the keeping quality of the mussels. The mussels are relaid during 2–4 weeks on rewatering plots between production and marketing. It was feared that, after completion of the Storm-Surge Barrier in the Eastern Scheldt, the rewatering function would deteriorate as a consequence of accumulation of mussel-deposited mud (pseudo-faeces) and a decline of water quality during periods of low current velocity. A research program was drafted in order to make a prognostication of sedimentation and erosion and of the occurrence of adverse water quality and food shortage on the plots after the completion of the Storm-Surge Barrier.

A study was made of erosion factors such as tidal currents, wave action and periodical dredging of mussels on the plots. Besides, food content and water quality parameters were measured. The measurements were carried out during 13-hours periods at half-hourly intervals. Periodic dredging of mussels on the plots appeared to be the most important among the erosion forces, while tidal currents and wave action have less impact.

Sedimentation is almost entirely caused by the filtering activity and deposition of faeces by the mussels. It is expected that after the completion of the Storm-Surge Barrier the erosion forces will decrease slightly.

Whether the erosion and sedimentation balance on the rewatering location, presently more or less in equilibrium, will change, will mainly depend on the future rate of faeces production. This, however, is difficult to predict.
Water Quality Aspects of the Nakdong Estuary Barrage
Authors: van Sluis J W , Lijklema L
Published: May 2018

As a result of the construction of a barrage in the estuary of the Nakdong river the size of the estuary will be considerably reduced. In addition, a large river reservoir is created upstream of the barrage.

Main points of interest are the effects of the discharge of raw sewage and treated effluent into the Nakdong river on the water quality in the projected reservoir and the water quality forecasts for the remaining part of the estuary, in relation with the existing plans for sewerage and sewage treatment for the city of Busan. In addition, measures to reduce the effects of the barrage and the outline of a water quality management programme are presented.

Special consideration is given to the methodological aspects of the water quality study, i.e. the selection and use of mathematical models in a situation where input data are rather uncertain and only very few data for parameter estimation and model verification are available.
Implications for Coastal Engineering Projects of Studies, at the Tees Estuary, on the Effects of Reclamation of Intertidal Land on Shorebird Populations
Authors: Evans P R , Pienkowski M W
Published: May 2018

Proposed engineering projects usually require assessments of their likely environmental effects, often to help determine the least harmful siting of such works. Even in cases where the projects are planned several years in advance, there is rarely sufficient time for a full predictive study of effects on the natural environment. In this paper we describe methods and report the accuracy of predictions made within a very limited time span of the effects on shorebirds of large scale partial reclamation of the Tees Estuary. We then summarize subsequent, more detailed studies on processes determining the numbers of shorebirds found at coastal sites and note how these can be used to help predictive studies elsewhere, provided that the personnel required to make the predictions are sufficiently experienced in work on coastal birds.
Environmental Management within the Framework of Land Use Planning along the Mediterranean Coast of Israel
Authors: Brachya V , Lerman E , Lerman R , Bukler N , Nir Y , Pratt I , Farkash M , Gordon N , Ben David Z , Green R
Published: May 2018

A multi-disciplinary team was commissioned by the Environmental Protection Service to prepare a statutory land use plan for the Mediterranean coast of Israel. Suitability for tourist and recreation development was assessed on the basis of geological, vegetation and landscape surveys. Five levels of intensity of development were defined for beach activities and four levels for visitor activities and accommodation in the hinterland. The allocation of level of development for each site along the Mediterranean coastline was checked in relation to resource sensitivity. The plan includes regulations for the protection of natural and manmade resources, for maximum visitor capacity, for beach services and accommodation, for the location of offshore structures and for development at river mouths,
The Hard Bottom Biocoenoses and the Fish Fauna of Lake Grevelingen, and Their Reactions to Changes in the Aquatic Environment
Authors: Waardenburg H W , Meijer A J M , Phillipart R J L , van Beek A C
Published: May 2018

In 1970 the Biological Working Group of the Dutch Underwatersports Association started an investigation of the hardbottom biocoenoses in the Grevelingen. Since 1979 we extended the investigation and since 1980 a monitoring investigation of the fish fauna in Lake Grevelingen has also been carried out. The aims of the investigations are to gain insight into the presence and coverage of the hard bottom biocoenoses and their reactions to changes in the aquatic environment, as well as to gain a continuous up-to-date insight into the presence of the various fish species, so that (management) measures can be advised.

In this paper, the results obtained in the period 1970 to 1983 are given. The authors recommend opening the sluice in the Brouwersdam for much longer periods and carrying out an active management using this sluice and the siphon sluice in the Grevelingendam, which can be put into use at the end of 1983.
Relating Effluent Control Parameters to River Quality Objectives Using a Generalised Catchment Simulation Model
Authors: Bowden K , Brown S R
Published: May 2018

A computer model has been developed which combines a simulation based approach with the modular logic of the steady-state catchment approach, and provides facilities for calibration and verification of simulated data against observed data. Temporal correlation of simulated variables (e.g. flow and concentration) is also possible.

This model has been used to study the River Wey basin with a view to assessing the impact of twelve significant sewage effluent discharges upon the river, to identify where action is needed to restore and maintain the quality of the River Wey and its tributaries, and to seek a solution combining the various options of revising sewage works' operating targets and making improvements to works' performance.

This study having been completed, the preferred options have been identified and are being put forward for discussion within the Authority.
An On-Line Monitoring, Data Management and Forecasting System for the Bedford Ouse River Basin
Authors: Whitehead P G , Caddy D E , Templeman R F
Published: May 2018

Data from Automatic water quality monitors and gauging stations on the Bedford Ouse are telemetered to the Cambridge office of the Creat Ouse River Division of the Anglian Water Authority. A mini-computer has been installed to log data from the out-stations, convert data to meaningful units, prepare data summaries, check for alarm conditions and forecast flow and quality up to 80 hours ahead at key locations along the river system. The system provides information on flow and quality conditions in real time and has been used to forecast the movement of pollutants along the river system. A generalised suite of computer programs have been developed for data management and forecasting and a micro-processor controlled water quality monitor is currently under development.
Water Quality Forecasting for Real-Time Control of Irrigation Pumping Schedules
Authors: Dexter Hilary , Petch James
Published: May 2018

This paper deals with the problems of using the River Jordan as a source of irrigation water for agricultural settlements in the area between Lake Kinneret and the Dead Sea. The river is polluted by chlorides from salt springs and the levels are very variable. A forecasting model for chlorides is proposed which will operate with a real-time system in order to minimize loads applied to crops. The Box-Jenkins methodology is shown to provide a suitable model with the severe constraints of data availability. The statistical and operational success of the model are examined for forecasts at one abstraction point on the Jordan. Model development continues.
A Process Based Model of Faecal Bacterial Levels in Upland Catchments
Authors: Jenkins A , Kirkby M J , McDonald A , Naden P , Kay D
Published: May 2018

In this paper a process based model of bacterial dynamics in a river is developed. It is suggested that such models may be of value in relation to the management of catchments where the waters are destined for potable supply. To do this we draw upon the results of previous papers to identify those factors that have a bearing on the development of the model. The elements of the model are then specified and the rationale for particular aspects of the structure is discussed. Sample output is provided to demonstrate that the model is capable of simulating some of the bacterial conditions for which data exist. Finally, conclusions are drawn in respect of (1) those areas of research that would be most effective in refining the model and (2) the situations where the model might be applied.
Time Patterns of Rainfall for Estimating Design Floods on a Frequency Basis
Authors: Cordery I , Pilgrim D H , Rowbottom I A
Published: May 2018

The rainfalls used in the practical estimation of design floods are generally based on frequency-duration relationships derived from recorded intense bursts of rainfall of various durations rather than from complete storms. These recorded intense bursts are therefore used in the derivation of the temporal patterns. The method produces patterns that incorporate the average variation of intensities and the most likely sequence of these varying intensities. Use of these patterns should minimize the introduction of joint probabilities into the design flood model and aid in estimation of a flood with the same frequency as the design rainfall. The method provides patterns with average or typical variations in intensity, in contrast to simple averaging which is shown to be generally unlikely to yield satisfactory patterns. The derived patterns are shown to provide peak flood estimates which are higher than those given by constant intensity storms but lower than rearrangements of the frequency-duration relationships.
Methods for Calculation of Annual and Extreme Overflow Events from Combined Sewer Systems
Authors: Johansen N B , Harremoës P , Jensen M
Published: May 2018

Overflow from combined systems constitute an increasing source of pollution of receiving waters, as compared to daily wastewater discharges which undergo treatment to a still higher extent. The receiving water problems from overflows are significant both in a long term scale (mean annual load) and in a short term scale (extreme event load). A method for computation of both annual and extreme load is presented. It is based on historical rain series and the use of a time-area model and simple pollutant mixing model in runoff calculation. Statistical calculations for both mean annual load and extreme events have been applied to the computed overflow series. Based on the computerized method simple manual calculations methods have been developed, resulting in graphs and tables for annual load and extreme load.
The Two-Step Nitrification of Ammonia-Rich Waste Water
Authors: Pascik Imre , Mann Theo
Published: May 2018

In a refinery, pilot plant studies have been carried out for the nitrification of waste water containing 700 to 900 mg/l ammonia. The aim was to work out a treatment concept that could be used to build a full scale plant for nitrogen elimination by nitrification and denitrification.

The optimal treatment method found was the two-step nitrification method, where−the first step (high NH4+-load) results in a BOD-elimination and a partial nitrification (60 to 85% of the NH4+-load), and−the second step (low NH4+-load) results in an oxidation of the remaining NH4+-oxidation down to 10-25 mg/l NH4+.

By this process the aeration volume required for the nitrification was reduced by approximately 40%. The full-scale plant designed for the elimination of 8 000 kg NH4+ per day started operation in July 1981.
Relationship between Surface Loading, Depth and Effluent Suspended Solids at a Rectangular, Horizontal Pilot-Scale Secondary Clarifier
Authors: Ditsios M
Published: May 2018

This paper deals with the selection of depth necessary for final clarifiers depending on hydraulic surface loading qA (m3.m−2.h−1), on settled sludge volume VSV (ml.l−1, dilution method, see W. Merkel, 1971), on the return sludge ratio (RV, percent) and on TSe (mg.l−1), the total filterable residue in the effluent.
Studies of Anaerobic Treatment of Sulfite Process Wastes
Authors: Ferguson John F , Benjamin Mark M
Published: May 2018

A series of laboratory studies of treatment of sulfite process wastes constitute a case study of application of high rate anaerobic biological treatment. Sulfite evaporator condensate (SEC) was evaluated in batch and continuous flow studies to find the efficiency of treatment that was possible and the conditions suitable for treatment. The role of sulfur and neutralization in the process were especially significant. Caustic extraction stage bleaching wastes (CE) were also studied for their use in neutralizing the evaporator condensate. Toxicity effects requiring dilution were found, but both CE and SEC can be treated, removing most of the BOD in a high rate process at detention times believed suitable for commercial application.
The Taman Anaerobic Process – for Wastewater from Mechanical Pulp and Paper Production
Authors: Rekunen S , Kallio O , Nyström T , Oivanen O
Published: May 2018

Anaerobic waste water treatment is the great step in the right direction, because most of the operating costs can be covered with the biogas generated in the process. This was the reason why the Tampella Anjala Paper Mill undertook pilot plant studies after completion of laboratory tests. This paper discusses the results achieved with the TAMAN multi-stage reactor and with the control reactors. The waste water used in the research originated in the manufacture of mechanical pulp and paper and at the debarking plant. The economic advantages of the TAMAN process are also compared with those of the activated sludge process.
Process Control in Anaerobic Wastewater Treatment
Authors: Frosteil Björn
Published: May 2018

The monitoring and control of anaerobic waste water treatment is discussed. In a first section optimum biological conditions were given. These are a nutritionally balanced waste water free from oxidants and toxicants, a temperature of 55-60 °C and a pH of 6.8-8.0.

In a second section, parameters for monitoring and control were discussed. It was concluded that present system designs usually allow for the control of influent flow rate and temperature but not for the key parameter solids retention time (SRT). Process control in anaerobic waste water treatment, therefore, is more monitoring than control, a situation that is unsatisfactory.
The Role of Facultative Anaerobic Micro-Organisms in Anaerobic Biodegradation of Chlorophenols
Authors: Hakulinen R , Woods S , Ferguson J , Benjamin M
Published: May 2018

Pure cultures of facultative anaerobic bacteria and yeasts were isolated from anaerobic reactors fed synthetic wastewater which contained eight different chlorophenolic compounds. The concentration of facultative anaerobic micro-organisms was followed in the reactor throughout the experimental period, during which the chlorophenol concentrations were increased and many of the chloronated phenols were removed nearly completely.

The most common species were Klebsiella spp. and K. Pneumoniae. Some of the common colonies were tentatively identified as Pseudomonas-like organisms and Aeromonas hydrofila. Methanogenic bacteria in the reactor were mainly acetate users. When the total chlorophenol concentration in the feed was increased from zero to 2.4 or 5.3 mg/1, the concentration of Pseudomonas-like organisms increased, as did the concentration of yeasts.

Pure and mixed cultures were tested for use of 2,4,6-trichlorophenol (246-TCP) as a sole carbon and energy source under anaerobic conditions. None of the isolates were able to degrade 246-TCP under anaerobic conditions in pure culture. However, mixed cultures containing only P. aeruginosa and K. oxytoca were able to degrade 246-TCP.
Anaerobic Treatment of Fibre Board Mill Wastewater
Authors: Kroiss H , Svardal K
Published: May 2018

The specific pollution load per ton of fibre board at an Austrian factory is in the range of 110 kg COD or 50 kg BOD5. Aerobic treatment would result in unacceptable costs (energy, nutrients, sludge handling). Semitechnical pilot scale investigations showed that anaerobic treatment can lower the BOD5 to about 80 % and the COD to about 75 %. But it was not possible to maintain these efficiencies over longer periods (several months). Labscale experiments resulted in stable and very high removal efficiencies (94 % BOD5, 86 % COD). Reliable neutralization was shown to be necessary for good results.
Sludge Characteristics in Uasb-Reactor Treating Thermomechanical Pulping Effluents
Authors: Vuoriranta P J , Rintala J A , Kirjavainen H
Published: May 2018

Sludge from laboratory scale UASB-reactors under various operating conditions and sulfur concentrations was characterized by using electron microscopy and microbiological methods.

The objective of this research was to evaluate factors effecting sludge granulation and the relationship between sludge morphology and sludge activity, measured as a function of biogas production.
Concentration of Viruses from Water using Pig Erythrocyte Ghost Cells
Authors: Armon R. , Kott Y. , Neeman Y.
Published: May 2018

Ghost cells (made from pig erythrocytes) were used as a sorptive matrix to concentrate bacteriophages ϕx-174, MS-2, f2, and Poliovirus LSC-l strain from small volumes of water. Adsorption-elution process was similar to the organic flocculation method, (adsorption performed at pH 3.5) but instead of beef-extract floc, erythrocyte membranes were used. The adsorption achieved ranged 93-100% with various bacteriophages and 97-100% with Poliovirus LSC-1 strain, elution ranged 92-102% with bacteriophages and 84-347% with the Poliovirus. Comparing ghost cell results with 3% beef-extract from different sources, the pig erythrocyte ghost cells were always found to be superior.
Detection of Enteroviruses: An Assessment of Ten Cell Lines
Authors: Morris R.
Published: May 2018

The routine monitoring of waters and wastewaters using the BGM - suspended cell plaque assay system has resulted in high isolation rates for polio and coxsackie B viruses with echoviruses only rarely being detected.

Ten cell lines (five of human origin, five of simian derivation) were examined for their susceptibility to twenty six enteroviruses and their ability to isolate naturally occurring enteroviruses in wastewater effluent determined.

All the viruses produced cytopathic effect in the simian cell lines but only in the FL amnion line of human cells. The detection of naturally occurring enteroviruses was most efficient when BGM cells were used with 82% of samples being positive. RD cells gave 73% positive whilst chimpanzee liver gave 64%. However, the number of plaques formed in the presence of each cell line showed that BGM detected 50% of all plaques observed with RD and chimpanzee liver detecting 21% and 9% respectively. The serotypes detected in this study were of the polio and coxsackie B groups, no echoviruses being identified.
Interactions Between Biotic and Abiotic Factors and Viruses in a Water System
Authors: Walter R. , Dürkop J. , Friedman B. , Dobberkau H. J.
Published: May 2018

A river intensively used along its entire course for extracting potable water and for discharging domestic and industrial effluents permanently carries a high load of viruses, including hepatitis A and rotaviruses. In the areas supplied with potable water from this river hepatitis A is endemic. The river has been investigated four times at 16 or more sampling points throughout its course in the years 1981, 1982 and 1983. Coincident with the virological investigation, biological, microbiological and chemical examinations were conducted with the same water sample. At some representatively distributed sampling points along the river course, tests for heavy metals (Cd, Ni, Cu, Cr, Pb) and selected chemical compounds were also performed. The virological quality of the river water largely depends on the virus input via domestic sewage. Statistically significant correlations have been found between virus level, pH, NH4+ and NO3−. Amoebae species are likely to counteract viruses. Knowing the dynamics of river water exploitation above the extraction sites, a model for the estimation of virus content in the raw water could be developed.
Virus Removal by Activated Sludge Treatment
Authors: Shimohara E. , Sugishima S. , Kaneko M.
Published: May 2018

Removal of poliovirus 1 by activated sludge treatment in batch experiments was investigated, virus counts were reduced by more than 99% under conditions of 0.2 to 0.4 kg BOD.kg MLSS−1.day−1 and MLSS concentrations of 1,000 to 2,000 mg.l−1. There were no distinct relationships between BOD-SS loadings or TOC of the effluent and virus inactivation rates. MLSS levels of more than 800 mg.l−1 were necessary for more than 99% reduction in viral counts. Although MLSS levels of more than 2,000 mg.l−1 reduced viral counts by 4 log values, factors such as low temperatures and anaerobic conditions which adversely affect the efficiency of activated sludge processes, resulted in prolonged virus survival.
Competition in Biofilms
Authors: Wanner O. , Gujer W.
Published: May 2018

Based on a continuum approach to the biofilm problem and on mass balance equations, the competition of several microbial species for space and substrates is described. For the case of steady state and of autotrophic and heterotrophic organisms with given biological kinetics and a common nutrient (oxygen), the effect of relative substrate concentrations on biofilm performance and composition is discussed. The approach allows for a detailed analysis and for an adequate reproduction of experimental observations.
Determination of Kinetic Constants of Activated Sludge Microorganisms
Authors: Čech J. S. , Chudoba J. , Grau P.
Published: May 2018

A respirometric method for measuring kinetic constants of activated sludge microorganisms by means of a simple respirometer was developed and tested by using two types of mixed culture. It has been found that both the maximum substrate removal rate and the half-velocity coefficient are basically lower with the mixed cultures cultivated in a completely-mixed reactor /filamentous/ than with those cultivated in a selector-type reactor /nonfilamentous/.
Dynamics of Nitrification in a Biological Fluidized Bed Reactor
Authors: Hermanowicz Slawomir W. , Ganczarczyk Jerzy J.
Published: May 2018

Dynamics of nitrification in a biological fluidized bed reactor was investigated with numerical simulations and experimentally in a small scale reactor. A mathematical model was developed describing reactor dynamics, substrate removal and biomass development. Variable microbial activity was used as a quantitative representation of the state of the microorganisms. External and internal mass transfer limitations were considered in substrate removal modelling. The effects of biofilm growth on reactor hydrodynamics and on substrate removal kinetics were incorporated into the model. In the experimental part, the performance of the nitrifying fluidized bed was monitored as the influent concentration was varied following an irregular square wave pattern. The observed changes of the effluent concentration depended not only on actual conditions but also on the past history of the system. Further analysis was carried with the help of the developed model. The concept of variable microbial activity was instrumental in explanation of the microbial dynamics. Predictive capacities of the properly calibrated model were demonstrated.
Mathematical Model of Simultaneous Organic Oxidation, Nitrification, and Denitrification in Rotating Biological Contactors
Authors: Watanabe Yoshimasa , Masuda Sumio , Nishidome Kiyoshi , Wantawin Chalermraj
Published: May 2018

Simultaneous organic oxidation and nitrification rates in the RBC are given using a mathematical equation. The equation was derived from a hypothesis stating that intrinsic oxygen uptake rate of the biofilm has a constant value at a fixed temperature , independent of the composition of the aerobic bacteria. Based on this hypothesis, empirical equations are proposed to describe the profile of intrinsic organic oxidation and nitrification rates. Computer simulation of the simultaneous organic oxidation and nitrification was carried out to confirm the empirical equations. The mathematical model of the simultaneous nitrification and denitrification is discussed and was tested by computer simulation.
Epidemiological Evidence for Helminth and Cholera Transmission by Vegetables Irrigated with Wastewater: Jerusalem – A Case Study
Authors: Shuval Hillel I. , Yekutiel Perez , Fattal Badri
Published: May 2018

This paper reviews and reanalyzes epidemiological data on the transmission of the helminthic diseases ascariasis and trichuriasis as well as cholera by vegetables and salad crops irrigated with untreated wastewater in Jerusalem between 1935 and 1982, based on a series of published papers and unpublished reports not generally available to professionals in the field of water pollution control. The findings provide strong evidence that both Ascaris and Trichuria infections were actively and massively transmitted to the general public who consumed vegetables irrigated with raw wastewater. The levels of infection dropped dramatically when the supply of contaminated vegetables was cut off but increased again rapidly on reintroduction of the wastewater-irrigated crops. The infection level subsided again when the practice was finally stopped in 1970. The epidemiological evidence from the 1970 cholera outbreak in Jerusalem indicates that wastewater-irrigated vegetables were the primary route of secondary infection once a few subclinical or clinical cases of cholera entered the city from areas outside the country where a cholera epidemic was underway. The evidence also indicates that farmers in an area where cholera is not endemic are particularly at risk when practicing irrigation with raw wastewater from a city underdoing a cholera outbreak. The need to treat wastewater to remove these pathogens prior to the irrigation of such vegetable crops is stressed.
Use of Peracetic Acid in Operational Sewage Sludge Disposal to Pasture
Authors: Fraser J A. L. , Godfree A. F. , Jones F.
Published: May 2018

Intestinal pathogens and parasites are a problem associated with the disposal of sewage sludge to pasture. Those of major importance are ova of the beef tapeworm (Taenia saginata) and Salmonella bacteria. Techniques for routine monitoring of pathogens and intestinal parasite levels in sludge together with design of simple methods for their removal have intensified, because disposal of sewage sludge to pasture is coming under increasing international surveillance.

The performance during field trials of a proprietary peracetic acid compound (containing 36 to 40% w/w peracetic acid), hereafter referred to as PAA (100%), is described. These trials under operational conditions showed it to be a suitable bacterial and ovicidal agent for the disinfection of raw, digested and activated sludges.

Concentrations ranging from 250 to 1000 mg PAA/l have achieved up to 99% inhibition of hatching and up to 100% destruction in viability of tapeworm embryos suspended in raw and digested sludges.

Similarly these concentrations resulted in 5 log reductions in salmonellae seeded in raw sludge. A dose of 250 mg PAA/1 reduced salmonellae levels from 4600 organism/100cm3 to <30/100cm3 during gravity thickening of surplus activated sludge. Results from 46 tanker loads of consolidated surplus activated sludge revealed that salmonellae levels were reduced from 2400 organisms/100 cm3 to <30/100 cm3 at doses of 500, 400 and 300 mg PAA/1. At a lower dose of 150 mg PAA/1 levels were reduced to within a range of <30 to 430 organisms/100 cm3.

At optimum disinfection concentrations for the destruction of both bacteria and parasites, PAA was rapidly utilised resulting in safe, readily biodegradable, non-toxic residuals. The technical and practical benefits, principals of disinfecting sludge and ecological safeguards are highlighted in this paper. Use is made of case histories to describe practical operating techniques.
Considerations on Water, Oil and Air in Porous Media
Authors: Schiegg H. O.
Published: May 2018

Oil, a hydrocarbon spilled above a phreatic aquifer, initially percolates primarily vertically until it reaches the capillary fringe. Subsequently, the oil migrates within the capillary fringe parallel to the groundwater table thereby creating an oil-polluted layer parallel to the groundwater table. The mean thickness of such an oil-polluted layer is denoted by .

The objective of this paper is to describe as a function of the thickness of oil in an observation well and of the oil potential, respectively. For oil to enter a porous medium, a minimum value of is necessary and will be determined.

The paper starts by explaining the relationship between the water-air saturation curve and the saturation curves for water-oil and oil-air as expressed by the scale factor Ω. Subsequently, the phenomenon of capillary pollution is described. The influence of hysteresis in capillarity on the above considerations is shown at the end of the paper.
Sludge Conditioning: Effects of Sludge Biochemical Composition
Authors: Bowen P. T. , Keinath T. M.
Published: May 2018

Variations in response of three different sludges to conditioning with organic polyelectrolytes were evaluated with respect to the carbohydrate, protein and lipid content of the sludges. These biochemicals comprise the surfaces of most sludges. The difference in the concentration of these compounds is intrinsic to the sludge type. Polymer Index (PI) , a measure of minimum polymer dose required to achieve maximum dewaterability, was statistically related to each of the three components. Carbohydrate content correlated most strongly with PI. As carbohydrate content increases, PI was found to decrease indicating better polymer performance. Biopolymers, which are composed mainly of carbohydrates may surround the cells forming a highly reactive surface. These exocellular materials also promote bioflocculation. Both actions result in a lower polymer requirement for destabilizing the sludge. Protein and lipid were not observed to have strong correlation with PI. Cellular surfaces and structures are composed of these components. The low correlation indicates these components are less favored than carbohydrates for polymer interaction.
The Selective Cultivation of Easily Harvestable Algae Using Crossflow-Microscreening
Authors: Pretorius W. A. , Hensman L. C.
Published: May 2018

The implementation of algal systems as a viable wastewater treatment option has been seriously limited by the availability of cost effective techniques for removing algae from the effluent stream. In this study, the problem of biomass separation was overcome by the selective cultivation of algae species which could be removed effectively by simple screening. The selection of desired species was achieved by a combination of short hydraulic space time and various size micro-screens operating as algae selectors on the effluent stream. A high rate algae growth system, in which the mean cell residence time and hydraulic space time could be manipulated independently, was developed.

With humus tank effluent as feedstock, a hydraulic space time of 10 hours and a 200 µm opening size crossflow-microscreen, the filamentous green algae, Stigeoclonium, became the dominant species. This selected culture could be readily maintained at any predetermined concentration in the system with less than 20 mg/ℓ suspended solids in the effluent. The biomass produced was exceptionally easy to harvest.
Biological Assessment of Water Quality in Running Water Using Macroinvertebrates: A Case Study for Limburg, The Netherlands
Authors: Tolkamp Harry H.
Published: May 2018

To obtain suitable biological methods for evaluating water quality several methods were applied to the macroinvertebrate composition of streams in the southern region of the province of Limburg (the Netherlands). After evaluation of the results through comparison followed by elimination of unsuitable methods (e.g. Trent Biotic Index, Indice Biotique, Indice de Qualiteé Biologique Globale) four methods remained promising: the Saprobic-index, the Quality-index, the BMWP-aspt and the Chandler-aspt. A further selection of methods must be carried out in combination with a typological classification of the streams concerned, including a description of the achievable range for each method. To this end more research in the field of stream typology is needed, especially for the province of Limburg with its high diversity of streams.
Water Quality Modeling of the Lower Han River, Korea
Authors: Tischler L. F. , Bradley R. M. , Park S. J. , Rhee D. G.
Published: May 2018

The Han River Basin in the Republic of Korea covers an area of about 27,000 sq km south of the Demilitarized Zone, almost one quarter of the total area of the country. The total population in the basin is of the order of 13 million, of which more than 80 percent are concentrated in the urban contrbation of Greater Seoul alongside the Lower Han River. Within the vicinity of Seoul the river is used extensively for water supply, irrigation and both contact and non-water contact recreation. Treated nightsoil, untreated sullage, partially treated sewage and industrial wastes generated in the urban areas are also discharged to the river which is heavily polluted in the downstream reaches as a result. The finite difference water quality model QUAL-II was adapted to the Lower Han River using data obtained from extensive field water quality surveys especially designed to provide the necessary calibration and verification data base. Hydraulic data for the model were obtained from operation of the U. S. Army Corps of Engineers HEC-II computer model. Model calibration and verification was confirmed by statistical comparison of model simulations with the field data. The calibrated model was used to evaluate a number of different treatment alternatives for two different future years. Extensive model sensitivity analyses were run on both the key model parameters and the treatment alternatives to quantify the reliability of the prediction.