bluuebunny/crossref_metadata_2025 huggingface dataset:
Effective Monitoring Strategies for Demonstrating Water Quality Changes from Nonpoint Source Controls on a Watershed Scale
Authors: Spooner Jean , Line Daniel E.
Published: May 2018

Demonstrating water quality improvements from nonpoint source (NPS) controls by monitoring both land treatment and water quality in at least a subset of watershed projects is necessary to provide feedback to project coordinators Feedback to regional and national policy makers is also essential to achieve political and economic support for NPS control programs. To meet this objective, two challenges must be met in designing the monitoring network and analyzing the data: (1) Detecting significant (or real) trends in both water quality and land treatment implementation and (2) Associating water quality trends with land treatment trends.

Land treatment and water quality monitoring requirements for meeting these challenges are discussed based on lessons learned from the Rural Clean Water Program, a 10-15 year experimental program designed to control agricultural NPS pollution in rural watersheds. At minimum, monitoring of land treatment and water quality should be multi-year before and after best management practice (BMP) implementation. The paired watershed design is the best for documenting BMP effectiveness in the shortest number of years (a minimum of 3-5 years). The water quality and land treatment data bases should be temporally related. All significant sources of variability in the land treatment and water quality data should be taken into account to increase the chances of isolating true water quality changes due to BMPs.
Mobilization and Removal of Contaminants Associated with Urban Dust and Dirt
Authors: Dempsey B. A. , Tai Y. L. , Harrison S. G.
Published: May 2018

The objective of this research was to examine the effects of pH and contaminant/sorbent concentrations on the partitioning of contaminants in urban dust and dirt An emphasis has been placed on the environmental behavior of trace metals. Contaminants in urban dust and dirt are primarily associated with particles, even after suspension in runoff water for several hours to days. This affects the reactivity, toxicity, and mobility of the contaminants. Particle size distributions (PSD) for urban dust and dirt and partition coefficients (Kp) for the distribution of various contaminants between the water and the particles of various sizes are described. Where streams have very low alkalinity or in areas affected by acid precipitation, there can be substantial decrease in pH with dilution of the initial runoff. This has a significant effect on the speciation of contaminants, and therefore on the reactivity and mobility of contaminants in urban runoff.
Integrating Water Quality Modeling with Ecological Risk Assessment for Nonpoint Source Pollution Control: A Conceptual Framework
Authors: David Chen Y. , McCutcheon Steve C. , Rasmussen Todd C. , Nutter Wade L. , Carsel Robert F.
Published: May 2018

The historical development of water quality protection goals and strategies in the United States is reviewed. This review leads to the identification and discussion of three components (i.e., management mechanism, environmental investigation approaches, and environmental assessment and criteria) for establishing a management framework for nonpoint source pollution control. Water quality modeling and ecological risk assessment are the two most important and promising approaches to the operation of the proposed management framework. A conceptual framework that shows the general integrative relationships between water quality modeling and ecological risk assessment is presented.
On the Potential of Real Time Control of Urban Drainage Systems
Authors: Nelen Fons
Published: May 2018

The conventional solution to urban drainage problems employs a system with a certain storage, transport and treatment capacity. The limited efficiency of this solution is due to the lack in flexibility in operating the system under dynamic loading. Optimal systems performance can only be achieved by means of real time control (RTC) of the system. The potential of RTC should be considered not only after the system has been constructed, but in the design phase of the system as well, as it will influence the required capacities of the system elements. A model is presented that can be used to assess this potential on the basis of simulation of time series of rain events. For a simple fictitious system it is shown that by means of RTC considerable savings can be achieved. These are expressed in terms of extra storage or discharge capacity that would have been required in an uncontrolled system to reach the same overflow volume as when RTC is applied. Besides it is demonstrated that currently monitored process data provide sufficient information to operate the system in a proper way. Inflow forecasts may be useful but they are not absolutely necessary to derive a suitable operation strategy.
Stricter Standards for Stormwater Overflow of Sewer Systems in The Netherlands
Authors: Provoost K. J.
Published: May 2018

The effectiveness of sewer systems in the Netherlands has been reassessed taking into account the development of policy and financial-economic perspectives. Stormwater overflows are increasingly seen as having a major impact on water quality. Policy measures to address this situation are outlined.
Biological Phosphorus Removal from Wastewater by Anaerobic-Anoxic Sequencing Batch Reactor
Authors: Kuba T. , Smolders G. , van Loosdrecht M. C. M. , Heijnen J. J.
Published: May 2018

In this study an anaerobic-anoxic SBR (sequencing batch reactor) was used in order to investigate the possibility of phosphorus removal utilizing nitrate as an electron acceptor, instead of oxygen in biological phosphorus removal processes. The reactor was supplied with synthetic wastewater, in which acetic acid (HAc) and phosphate were added at concentrations of 400 mg-COD/l and 15 mg-P/l. A conventional anaerobic-aerobic SBR was also operated to compare with the anaerobic-anoxic SBR. The objectives of this research are to examine (i) feasibility and stability of the systems, (ii) kinetics and stoichiometry of phosphorus release and uptake. The anaerobic-anoxic SBR operation resulted in a stable phosphorus removal and accumulation of phosphorus removing bacteria using nitrate as an electron acceptor. Immediately after inoculation from a phosphorus removing plant (Renpho system) phosphorus uptake was observed, indicating that phosphorus removing bacteria which are able to utilize nitrate were already present in conventional phosphorus removing sludge. Comparison of stoichiometry and kinetics with the conventional anaerobic-aerobic SBR system shows a similar potential for phosphorus removal by denitrifying organisms. Therefore in the design of phosphorus removal processes one should not be afraid of nitrate, but use it.
Using Air-Lift Pumping as an in-Situ Aquifer Remediation Technique
Authors: Gvirtzman H. , Gorelick S. M.
Published: May 2018

The global attempt to protect and restore the major water resources encouraged hydrologists to develop new, simple and effective aquifer remediation methods. A new in-situ remediation procedure is proposed to remove Volatile Organic Compounds (VOC) dissolved in groundwater. This is accomplished by injection of air into a well, using a combined technique of air-lift pumping with a form of vapor stripping. The feasibility of the proposed method was analyzed using concepts of mass transfer of VOCs from water to air-bubbles and transport of VOCs in porous media.
Chemical and Physical Properties of Emissions from Kuwaiti Oil Fires
Authors: Stevens R. , Pinto J. , Mamane Y. , Ondov J. , Abdulraheem M. , Al-Majed N. , Sadek M. , Cofer W. , Ellenson W. , Kellogg R.
Published: May 2018

After the Iraqi retreat from Kuwait in 1991, airborne sampling was conducted in the oil fire plumes near Kuwait City and ground-level samples were taken of the air within the city. For the airborne sampling, a versatile air pollution sampler was used to determine the SO2, elemental concentrations, the aerosol mass loadings and SO42− and NO3 concentrations. Striking differences between the black and white plumes were associated with high concentrations of NaCl and CaCI2 measured in the white plumes and large numbers of carbon chain agglomerates in the black plumes. For the ground-based measurements, an annular denuder system was used to determine levels of SO2, SO42−, trace elements, and mass loadings. Certain pollutant levels rose in the city during inversion conditions, when winds were too weak to continue moving the combustion products directly to the Persian Gulf, and the increased levels of Pb and certain trace elements were comparable to those in other large urban areas in Europe.

This paper has been reviewed in accordance with the U.S. Environmental Protection Agency's peer and administrative review policies and approved for presentation and publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
Determination of the Parasitic Contamination of Irrigated Vegetables
Authors: Gaspard P. , Schwartzbrod J.
Published: May 2018

In countries with limited water resources, the agricultural use of treated wastewater represents an interesting alternative. The recent World Health Organisation guidelines (1989) for the microbiological quality of treated wastewaters used for crop irrigation require an arithmetic mean of ≤ 1 intestinal nematode egg per litre. In this study diverse methods have been tried for recovering parasitic nematode eggs from vegetables artificially contaminated by Ascaris eggs. The vegetables examined were lettuce and tomatoes. Vegetables were seeded with Ascaris eggs at different levels from 3 to 900 eggs. Eggs elution was realized with chemical solution (distilled water, aceto-acetic buffer pH 4.5, formalin 20%, anionic detergent DDN50®, cationic detergent hyamine®) and/or mechanical treatment (brush - scrub or brush - scrub coupled with glass powder treatment). Concentration was performed by flotation technique with a 55% zinc sulphate solution (d=1.3). Recovery was low for all samples after chemical elution. When we tested the association of chemical and mechanical treatments the percent recovery were ranging from 72 to 100% for vegetables contaminated with 10 to 400 eggs. The method proposed includes an elution with a glass powder suspension in a cationic detergent (50/50), a concentration with ZnSO4 55% solution (d=1.3) and a quantification with a counting cell. The sensitivity threshold of the proposed method lies at about 10 eggs per samples.
Microbiological Purification of Fish Grown in Fecally Contaminated Commercial Fish Pond
Authors: Fattal B. , Dotan A. , Parpari L. , Tchorsh Y. , Cabelli V. J.
Published: May 2018

The digestive tracts of tilapia reared in commercial fish ponds with animal manure and/or municipal wastewater generally were contaminated with the fecal indicators E.coli and enterococci to levels greater than those in the environmental water. When the indicator densitites in the water were sufficiently high, the liver and muscle tissue also became contaminated, albeit to much lower levels. Thermotolerant aeromonas were recovered from the environmental water and fish tissues at levels 2-4 logs higher than those of the fecal indicators. Accumulation of the indicators in the tissues of the naturally contaminated (pond) fish generally was greater than that in the artificially contaminated fish.

The indicator levels in the tissues did not appreciably decrease when the pond-reared fish were maintained for 5-8 days under starvation conditions in tanks containing water which was not exchanged. However, the E.coli and virus levels in the tissues of experimentally contaminated tilapia were appreciably and significantly reduced under the same conditions. The results point out the limited value of conventional “purification” methods as applied to tilapia reared in fecally fertilized waters and of data obtained from studies with experimental animals. Since fish are cooked prior to consumption, the major public health concern could be the risk of Aeromonas wound infections among individuals who handle and process fish.
Soil Microarthropods on Post-Fire Pine Forest on Mount Carmel, Israel
Authors: Broza M. , Poliakov D. , Weber S. , Izhaki I.
Published: May 2018

Soil microarthropods of pine forests in Israel were investigated for the first time. Eighty percent of them belonged to the orders Acari and Collembola, the remainder to another 18 orders. In the second post-fire year only 11 orders were presented. The groups Protura, Palpigradi and Pauropoda in Israel are described here for the first time. Protura and Pauropoda were quite common in the natural forest, but disappeared almost entirely after the fire. By contrast, the pseudococcid Rhizoecus sp., and to some extent also Palpigradi, were rare in unburned forest but behaved as pioneers and flourished two years post fire.

The Collembolan fauna were studied in more detail and four genera new to Israel have been identified already. The family Poduridae was the most common Collembolan in natural forest, but they almost disappeared after the fire, while the entomobryoid springtails did not change too much. It was concluded that soil microarthropods play an important role in post-fire succession and are good indicators of resilience processes.
Application of Laser Induced Luminescence in Ecology
Authors: Gaft M.
Published: May 2018

Exhaustion of rich ore deposits is making it necessary to bring low-grade ores into production, resulting in a sharply increased volume of excavated rock. Huge quantities of waste fill vast areas of the Earth's surface, with severe ecological effects. But the ecological damage could be reduced by extracting additional products from the tailings. Laseroluminescent sorting is a new technology by which this may be achieved. The most promising subjects are about 50 minerals including diamonds, native Au and Ag, ores of V, Pb, Zn, Sn, Li, Be, W, Mo, Zr, Sr, halite, apatite, phosphorite, fluorite, calcite, barite, anhydrite.
Transport of Dissolved Organic Carbon-Derived Natural Colloids from Bed Sediments to Overlying Water: Laboratory Simulations
Authors: Valsaraj K. T. , Thoma G. J. , Porter C. L. , Reible D. D. , Thibodeaux L. J.
Published: May 2018

Natural colloids are part of the carbon cycle arising from sediment diagenesis. Natural colloids can be quantified as the dissolved organic carbon (DOC) present in the pore-water of sediment beds. In this paper we demonstrate that DOC is mobile in a system in which the dominant transport mechanism is Brownian diffusion. A simple model which assumes constant physico-chemical properties for the DOC adequately predicts the DOC release rate from a sediment bed in a microcosm. A single adjustable parameter, the water diffusivity, is used to fit the model to the experimental data. The experimental diffusivities obtained from the fitted data agree well with previously presented values.
Field Application of a Steady-State Mass Balance Model for Hydrophobic Organic Chemicals in an Estuarine System
Authors: Dilks D. W. , Helfand J. S. , Bierman V. J. , Burkhard L.
Published: May 2018

A one-dimensional, steady-state mass balance model was applied to describe instream and sediment concentrations of four hydrophobic organic chemicals in a discharge canal and receiving water bayou. The chemicals examined were hexachlorobenzene, hexachlorobutadiene, hexachloroethane, and 1,2,4-trichlorobenzene. The objective of the study was to test a mass balance modeling approach for relating point source effluents to resulting sediment concentration, in support of future implementation of national sediment quality criteria (SQC). The modeling effort relied upon ambient monitoring data that were collected for purposes other than supporting a modeling effort. Given data uncertainties and assumptions in the modeling framework, model results were reasonably consistent with observations in the receiving water bayou. There were large discrepancies between model results and observed sediment concentrations in the discharge canal. These discrepancies are likely caused by an undocumented source of chemicals to the canal sediments, due to historical landfilling of wastes; and/or canal sediment concentrations being in temporal disequilibrium, due to historically higher chemical loading. The merits of steady-state versus time-variable models for describing sediment quality are compared. Steady-state models are most appropriate for effluent permitting purposes, where the objective is to determine the long-term relationship jbetween wastewater loads and resulting sediment concentrations. A time-variable model framework will be required to establish model credibility for situations where the steady-state assumption is violated, although the required information on historical chemical loads is often unavailable.
Uprating and Development of a Regional Telemetry Scheme
Authors: Huntington R.
Published: May 2018

In 1988 Wessex Water decided that its 10 year old regional telemetry system was in need of major uprating and improvement to meet their changing requirements. This paper explains the philosophy adopted in making the changes and describes the actual improvements carried out. While still based on a centralised system, two important changes included the use of more sophisticated outstations and the provision of a networking facility to VDU's for use by geographically spaced operational staff.

A number of inter-linked software packages developed for the analysis, optimisation and modelling of data are described. Finally conclusions are drawn.
Modeling and Simulation of Wastewater Treatment Processes
Authors: Andrews John F.
Published: May 2018

Several different types of models which can be useful in describing the dynamic behavior of wastewater treatment plants are discussed. Included among these are (1) visual, (2) linguistic, (3) mental, (4) physical, (5) mathematical, and (6) fuzzy models. Some of the basic concepts of modeling with emphasis on the relationship of these to engineering research and practice are then presented, these being (1) differences in the use of, and expectations from, models by researchers and practitioners, (2) sources of information useful for model development, (3) the amount and type of testing needed for model validation, and (4) the required accuracy of models. Computer simulation is necessary for the solution of most dynamic models. Recent advances in both hardware and software for personal computers have resulted in inexpensive, user-friendly systems suitable for use in both large and small organizations as well as by individual engineers.
On Line Respirometry: A Powerful Tool for Activated Sludge Plant Operation and Design
Authors: Watts J. B. , Garber W. F.
Published: May 2018

This paper will describe, with minimal reference to mathematically derived formulae, the importance and use of respirometry as a design and process operating tool. The authors will report on the latest findings of their team working in the United Kingdom. They will present case studies of events that were rapidly identified by the use of on-line respirometry.
Alternative Method for the Control of Balancing Tank at a Wastewater Treatment Plant
Authors: Mather A. J. , Shaw I. S.
Published: May 2018

Wastewater Treatment Plants are often designed with a balancing tank upstream of the bioreactors. The purpose of the balancing tank is to act as a buffer against large fluctuations in inflow volume and pollutant concentration. This paper presents the options available for control of the balancing tank. The paper also presents the results of simulation tests conducted to determine the effectiveness of a modelfree, neural-network-based controller, when used for balancing tank control.
DESIGN OF STORMWATER INFILTRATION FOR REDUCTION OF COMBINED SEWER OVERFLOW (CSO)
Authors: Rosted Petersen C. O. , Jacobsen P. , Mikkelsen P. S.
Published: May 2018

Stormwater infiltration is a significant tool for combined sewer overflow abatement because it involves a decrease in the impervious area connected to the sewer system. When allowing the infiltration structures to overflow into the existing sewer it is shown that for a required reduction in CSO-volume there exists an unambiguous relation between the infiltration structure volume and the size of impervious area connected to infiltration. Further, the presence of an optimal solution minimizing the total trench volume is pointed out. For a Danish sewer system with a travel time of 30 min and an interceptor capacity of 0.2 μm/s the optimal solution for reducing the CSO-volumes by 40 percent involves connecting 65 percent of the impervious area to infiltration trenches with a total storage volume of 3.6 mm. This corresponds to designing the trenches according to an exceedence return period of 0.04 yrs compared to the commonly applied design return periods of 2 to 10 yrs.
IDENTIFICATION AND APPLICATION OF A DYNAMIC MODEL FOR OPERATIONAL MANAGEMENT OF WATER QUALITY
Authors: Beck M. B. , Reda A.
Published: May 2018

The paper summarises recent progress in a long-term programme of research on an integrated approach to the management, md real-time control of water quality in river basins. The focus of this progrmnme is the development, md application of simulation models for the dynamic behaviour of wastewater treatment plants, and in-stream water quality. The model for the latter is based on a multiple continuously stirred tank reactor (MCSTR) approximation of fluid and solute propagation along a river system. Results are presented for the identification (calibration) of this model with reference to field observations from the River Cam in eastern England. These results illustrate the benefits of significant changes to the hydraulic basis of the model (relative to earlier applications). They also provide a good test of the model's capabilities in respect of solute transport, md the biochemical interactions among the five state variables of water quality, i.e., biochemical oxygen demand, dissolved oxygen, ammonium-N, nitrate- N, and chlorophyll-a. The model is applied to the assessment of management and real-time control strategies for attenuating the adverse effects on stream water quality of storm sewage surges passing from the sewer network and through the wastewater plant. The assessment includes the coordinated manipulation of in-stream hydraulic structures to improve controlled performance.
AN ANALYSIS OF THE EFFECT OF AN UPSTREAM RESERVOIR BY MEANS OF A MATHEMATICAL MODEL OF RESERVOIR HYDRODYNAMICS
Authors: Hocking G. , Straškraba M.
Published: May 2018

The reservoir hydrodynamic model DYRESM is used to investigate the difference in temperature stratification and flows in a solitary reservoir, and the same reservoir while in a cascade. The inflow 10 the reservoir changes in a cascade reservoir from an undammed river to the regulated flow from the hypolimnion of the upperlying reservoir, while the meteorological and other conditions remain unchanged. In agreement with previous findings of the strong effect of theoretical retention time on reservoir stratification, the comparison of a solitary and a cascade reservoir is based on hydrologically similar conditions. It is concluded that the change in the inflow temperatures manifests itself in the change from a lower degree of stratification and, an accumulation of cold water near the bottom in the solitary reservoir to a more pronounced stratification in the cascade reservoir. Comparing years with different RT, in a dry year (longer RT) the stratification is more pronounced both in a solitary and a cascade reservoir, the high flows in a wet year (shorter RT) producing much more rapid heating of the deep layers. The surface temperatures are lower in the cascade reservoir, too, being affected by mixing of the inflowing water with the surface strata. The heat budget of the reservoir is changed, more heat being taken up by the cascade reservoir as a consequence of the greater air-water temperature gradient. More intensive mixing of water masses is produced in the cascade reservoir under conditions of the same retention time, than in the solitary reservoir. The outflow temperature of the cascade reservoir is lower than the temperature of the solitary one. Another effect on the heat budget, not exactly studied in this paper, might be caused by the decreased extinction of light for the water in the cascade reservoir due to sedimenl < '1tion, phosphorus uptake and organic matter decomposition in the upperlying reservoir, causing lower turbidity, less phytoplankton, and less colour.
PROBABILISTIC METHODS FOR UNCERTAINTY ANALYSIS AND PARAMETER ESTIMATION FOR DISSOLVED OXYGEN MODELS
Authors: Masliev I. , Somlyódy L.
Published: May 2018

Water quality models are essential to the development of least-cost water quality control strategies based on ambient criteria. Such policies are particularly important if financial resources are limited which is currently the case in Central and Eastern European countries. In turn, the derivation of realistic model parameters is a pre-requisite of successful model application. Often, longitudinal water quality profile measurements are performed for the above purpose, but the traditional evaluation of this data encounters significant difficulties due to measurement and other uncertainties. Thus, probabilistic methods are preferred. This paper discusses two of them: the Hornberger‒Spear‒Young procedure using Monte Carlo simulation and a Bayesian approach. Both methods are rather generic, but they are applied here solely for the traditional Streeter‒Phelps model and its extensions. For the purpose of illustration, water quality measurements from the highly polluted Nitra River in Slovakia are employed as a part of a policy oriented study. The BOD decay rate obtained was rather high due to partial biological wastewater treatment and small water depth, but overall, derived parameter values were in harmony with literature findings. Alternative dissolved oxygen models (2‒3 state variables and 2‒5 parameters) could also be calibrated to the data set. Ranges of probability density functions (PDFs) for model parameters were rather broad calling for a well suited formulation of a water quality management model.
EVALUATION OF MODELLING TECHNIQUES FOR WASTEWATER TREATMENT PLANT AUTOMATION
Authors: Capodaglio Andrea G.
Published: May 2018

Wastewater treatment plant automation and real-time control have become important topics of research and development. Real-time control is nowadays considered a desirable goal for medium- to large-sized utilities for attaining better treatment efficiencies and improved compliance with discharge permit limitations. For an efficient implementation, real-time control must be supported by adequate modelling methodologies that take into full account the dynamic properties of the treatment system. This paper evaluates the requirements of such applications and the properties of available modelling approaches. Some applications examples are discussed.
Does the Rhine Still have Characteristics of a River Ecosystem? The Longitudinal Distribution of Macroinvertebrates
Authors: van der Velde G. , van den Brink F. W. B.
Published: May 2018

A structural and functional analysis of macroinvertebrate taxa was made in order to relate species richness and functional feeding groups to hydrological, physico-chemical, nutritional and habitat characteristics of the main channel transects of the entire river Rhine. Species diversity was highest in the upstream parts, Hochrhein and Oberrhein, and lowest in the Mittelrhein, which might be related to the greater variety of habitats and of nutritional resources and the lower degree of pollution in the upstream sections. The relative contributions of the macroinvertebrate species over the various functional feeding groups was remarkably constant with collector species dominating the species composition in all river sections, suggesting an overall importance of FPOM as macroinvertebrate food in the sections studied. The relative share of shredder species suggests the importance of the input of CPOM in the entire river from tributaries, riparian and floodplain vegetation.
Seasonal Development of Zooplankton in the Lower River Rhine during the Period 1987–1991
Authors: van Zanten B. , van Dijk G. M.
Published: May 2018

This paper presents some results of a five year monitoring programme on Zooplankton in the River Rhine at the Dutch sampling stations Lobith (German/Dutch border) and Maassluis (at the discharge of the river into the North Sea). During the entire period the Zooplankton composition showed an apparent seasonal pattern at both stations. This pattern was characterized by low densities during the winter and higher densities during the summer with an obvious spring peak. Zooplankton was dominated by rotifers with Brachionus angularis, B. calyciflorus, Keratella quadrata and K. cochlearis as dominant species. The possible role of environmental factors (flow rate and chlorophyll-a content) as controlling factors for Zooplankton dynamics is indicated.
REMOVAL OF VOCs FROM REFINERY AND PETROCHEMICAL WASTEWATERS USING DISSOLVED AIR FLOTATION
Authors: Al-Muzaini S. , Khordagui H. , Hamouda M. F.
Published: May 2018

A field sampling and analysis program was carried out at a refmery and petrochemical industrial complex in the Shuaiba Industrial Area to characterize the volatile organic compounds (VOCs) emitted from wastewater and examine their removal by dissolved air flotation (DAF) and granular activated carbon (GAC) treatment

Compounds such as benzene, toluene, ethylbenzene, and xylene were identified. The total VOC emission of these compounds ranged from 0.1 to 3.2 mglm3. The VOCs concentrations in wastewater ranged from 34 to 4445 g/l.

An actual refinery wastewater was fed at a rate of 10 l/min into a pilot scale 592-liter dissolved air flotation(OAF) unit connected to a granular activated carbon column. Results indicated that liquid detention time and air/water ratio were the main factors affecting VOCs stripping from the OAF basin. Up to 20% of influent VOCs concentrations were lost by volatilization at an air-to-water ratio of 0.5. Adsorption by dry granular activated carbon (GAC) was capable of reducing the VOCs concentration in off-gas from the OAF unit by more than 99%. It is recommended to couple covered OAF units with dry GAC columns to minimize occupational exposure to VOC emission.
A PROPOSED PATHWAY FOR THE BIODEGRADATION OF HEXAMETHYLENETETRAMINE
Authors: Colquhoun K. O.
Published: May 2018

A study has been performed on two Pink Pigmented Facultative Methylotrophic (PPFM) bacteria isolated from activated sludge previously exposed to Hexamethylenetetramine (Hexa), Colquhoun and Smith (1988) and Colquhoun (1988). There are four possible pathways found in methylotrophs which can be used to break down formaldehyde, one of the two constituents of Hexa (Zatman 1980). These pathways are: (i) Ribulose monophosphate pathway (RuMP); (ii) Xylulose monophosphate pathway (XuMP); (iii) Ribulosebiphosphate carboxylase pathway (RuBPC) and (iv) Serine pathway.

However, before any of these pathways can make use of the formaldehyde present in Hexa it must first be made available by breaking up the Hexa molecule. Two possible mechanisms by which Hexa might be broken down are proposed. The first reported by Tada (1960) and Strom and Won Jun (1980) whereby Hexa is broken down to formaldehyde and ammonia under acid conditions. This mode of action has been exploited when Hexa has been used in the long term therapy of chronic urinary tract infections with the antimicrobial activity resulting from the production of formaldehyde.

The other possible mechanism is a combined physicochemical and biological function proposed by Bodik et al. (1991). In this mechanism there is no direct biological action on the Hexa molecule, it is dependent upon the nitrification of ammonia which produces H+ ions which can hydrolyse Hexa to ammonia and formaldehyde. The formaldehyde is either metabolised or it exhibits an inhibitory effect on the microbial population whilst the ammonia is nitrified which in turn produces more H+ ions which hydrolyses more Hexa and perpetuates the cycle.

This study will demonstrate which of these degradative pathways is the most probable for the isolated PPFM's.
PILOT -SCALE, HIGH-STRENGTH INDUSTRIAL WASTEWATER TREATMENT EVALUATION BY MATHEMATICAL MODELLING
Authors: Dobolyi Elemér , Takács Imre
Published: May 2018

An existing rendering plant wastewater treatment facility has to be upgraded to meet the newly set British and more stringent EC effluent standards. After detailed analysis it turned out, that the existing treatment plant cannot be upgraded, a new plant has to be built. The rendering plant processes slaughterhouse wastes. The wastewater contains easily biodegradable organic substances, mainly organic acids, organic bonded nitrogen and ammonia. According to the new effluent standards the main task, besides the organic removal was the complete removal of nitrogen. The aim of this study was to find out the best available technology and the basic wastewater design data. For this purpose, on site pilot scale experiments were carried out. In several test runs the influent BOD and T K N have varied of between 1400-5500 and 460-1120 mg/l, respectively. Based on the experimental results, single-sludge nitrification-denitrification technology was selected for the full scale treatment plant. The plant was extended by chemical phosphate removal applying the post-precipitation method.

In addition to the experimental schedule, a mathematical model of the plant was developed for two purposes.– to verify the applicability of the general activated sludge model under high concentration influent conditions, and– to generalize experimental results and provide a tool to predict plant performance under full scale conditions.

On the basis of successful pilot plant experiments and model calibration, full scale plant design parameters were determined and presented. The full scale plant is under construction.
An Alternative Approach to Achieve a Clean River Meuse
Authors: Klink F. J.
Published: May 2018

The municipality of Rotterdam and two regional drinking-water companies jointly started an action programme in an attempt to reduce the sources of pollution in consultation with the dischargers. Rotterdam aims to reach written agreements with each relevant discharger in which the discharger is committed to reduce his discharge in order to improve the Meuse water quality. In exchange Rotterdam relinquishes legal claims upon the discharger. Results of the measured discharges are presented. The 8 major dischargers of Br, Cd, NH4 and P each contribute up to 79% of the total contaminant discharge into the Meuse.
Bioaccumulation Processes of Organic Pollutants by Animals of the River Rhine
Authors: Streit Bruno
Published: May 2018

An overview on background concentrations of inorganic and organic pollutants in the Rhine river is given. Temporary increases in concentrations on the occasion of chemical spills or agricultural use need applications of adequate bioaccumulation and clearance models to predict environmental behaviour of xenobiotics.
ADVANCED TREATMENT OF PAPER MILL EFFLUENTS BY A TWO-STAGE ACTIVATED SLUDGE PROCESS
Authors: Knudsen L. , Pedersen J. A. , Munck J.
Published: May 2018

The work presented in this paper concerns the application of a two-stage aerobic activated sludge process for treatment of effluents from paper mills in Denmark. The paper describes both pilot-scale test results and fullscale experience with the process.

The treatment process is characterised by a bigh-load first stage (2-4 kg COD/kg MLSSxd) followed by a low-load second stage to secure full nitrification and denitrification of remaining nitrogen compounds.

The results of continuous pilot-scale tests show that it is possible to obtain a reduction of more than 85% of the incoming COD,01 and a 99% reduction of the incoming BOD5, resulting in an effluent quality of 230 mg CODsol/l and less than 10 mg BOD5/l. As indicated, practically all the biodegradable organic substances are removed by the process. The remaining fraction of soluble organics measured as COD is considered to be non-biodegradable by conventional biological treatment systems. The results produced in the pilot-scale tests are confirmed by the effluent qualities obtained in a full-scale treatment plant at another paper mill, involving an identical process concept.

During the pilot-scale tests, special attention bas been paid to the removal of organic compounds, organic nitrogen as well as nutrients and nitrification. In addition, the sludge characteristics and the oxygen requirements have been considered.
ACTIVATED CARBON ADDITION TO ACTIVATED SLUDGE IN THE TREATMENT OF KRAFT PULP BLEACHING WASTES
Authors: Çeçen Ferhan
Published: May 2018

This study examines the effect of powdered activated carbon (PAC) addition to activated sludge in the treatment of pulp bleaching effluents which contain a large amount of nonbiodegradable matter. The effect of PAC addition has been studied in both batch and continuous-flow reactors. Isotherms were developed for PAC and biomass adsorption. It was shown that substrate removal by air stripping and biosorption was negligible. The change in substrate concentration occurred mainly by biodegradation. The biological removal data obtained in batch and continuous-flow reactors were fitted to kinetic models. Both batch and continuous-flow experiments revealed that there remained a high amount of nonbiodegradable substrate as expressed by residual COD and Color436. Carbon addition to activated sludge resulted in a high decrease in substrate concentration, particularly for color. However, the results indicated that there was no noticable biological enhancement with PAC addition. The combined PAC and activated sludge process seemed to be a combination of adsorption and biodegradation.
ADVANCED BIOLOGICAL TREATMENT OF PAPERMILL WASTEWATERS; EFFECTS OF OPERATION CONDITIONS ON COD REMOVAL AND PRODUCTION OF SOLUBLE ORGANIC COMPOUNDS IN ACTIVATED SLUDGE SYSTEMS
Authors: Franta J. , Helmreich B. , Pribyl M. , Adamietz E. , Wilderer P. A.
Published: May 2018

Sequencing batch reactor (SBR) experiments have been conducted in the laboratory to study factors affecting the composition and concentration of residual organics in the effluent of biological wastewater treatment plants. Wastewater discharged by a papermill was used in three SBRs. A fourth reactor was operated with a model synthetic wastewater in order to identify microbially-produced organic compounds in the effluent. The highest COD removal and the best sludge settling properties for the papermill wastewater were obtained with the greatest sludge age (20 days) and the longest react period (22 hours) investigated. Pyrolysis GC/MS studies showed that the residual COD from the treated papermill wastewater consisted of refractory organic compounds (i.e. lignins). These compounds bad a molecular size between 10,000 - 1,000 dalton and were responsible for the brown colour. Approximately 10% of the residual COD consisted of microbially-altered organics, the rest being organics initially present in the wastewater.
REMOVAL OF TRACE Cd (II) FROM AQUEOUS SOLUTIONS BY FUNGAL ADSORBENTS: AN EVALUATION OF SELF-IMMOBILIZATION OF RHIZOPUS ORYZAE
Authors: Huang Chihpin , Chiu Hsin-Huei
Published: May 2018

Rhizopus oryzae are grown in the fermenter as discrete and nearly spherical pellets. The pellets ' size and structure suggest that more agitation produces smaller and more compact pellets. In this study, the agitation intensity in the fermenter is changed to produce the suspension mycelium and pelletized mycelia with various sizes. Acid-washing and heat treatments are applied to deactivate the fungi. Experimental results indicate that acid-treated mycelia are preferential to either fresh or heat-treated pelletized mycelium for use in the binding of Cd (II) ions. Based on engineering and economic considerations, this study screens an optimum size of pellet to be 3.8 mm which is formed under 2 -day pre-cultivation and 5-day harvest in a fermenter at 300 rpm of agitation.
ON-LINE MONITORING AND CONTROL OF THE TEXTILE WASTEWATER COLOR REMOVAL PROCESS
Authors: Chang Cheng-Nan , Yu Ruey-Fang , Chao Allen C. , Tojo Seishu
Published: May 2018

On-line monitoring of the wastewater color and ORP values is used to carry out laboratory studies for collecting data to assist in formulating model equations that can be used to achieve better control and automation of the oxidation process for color removal from textile finish wastewaters. Laboratory studies show that the ORP value, the solution pH, the chemical dosage applied and the resulting color of the treated samples are well correlated by linear relationships. Additionally, the ORP value of the solution that is highly related to the color or the ADMI value of the sample being oxidized can be used as a control parameter of the oxidation process. Nernst equation is modified to generalize the findings and the reaction kinetics can be delineated by Ct = In (ADMIo/ADMIt). The term Ct is a function of ORP, pH and reaction time while ADMIt and ADMI, are the color of the raw wastewater and the treated effluent, respectively. Using the model, the dosage requirement, the color removal efficiency, and the time required to complete the oxidation reaction can be calculated. On-line monitoring and automatic control of the de-coloring process to achieve a more efficient and better cost-effective color removal can be made practical.
REMOVAL OF DYEW ASTE COLOUR FROM SEW AGE EFFLUENT – THE USE OF A FULL SCALE OZONE PLANT
Authors: Churchley John H.
Published: May 2018

Textile dyeing within the Severn Trent Region produces highly coloured wastewater. This dyewaste is usually discharged untreated to foul sewer. Conventional treatment at the receiving sewage treatment works removes little colour resulting in colouration of effluents and rivers in certain areas. The regulatory body (N.R.A.) has set strict colour standards on 5 of S.T.W.L. sewage works. These standards are based on a River Quality Objective (R.Q.O.).

Methods of removing colour are reviewed. The full scale ozone colour removal plant at Leek S.T.W. is described and early operating data is given. Good colour removal has been obtained, but compliance with the consent has been 89.7% and not the 100% required.

Data is presented to indicate that the R.Q.O. does not adequately take natural colour into account. Target aborbances at 400 and 450 nm are thus too low to be practicable for the derived sewage effluent consents.
Assessment of Spawning and Nursery Areas in the River Meuse
Authors: Vriese F. T. , Semmekrot S. , Raat A. J. P.
Published: May 2018

In commission of Rijkswaterstaat Directorate Limburg, a desk study was carried out by the OVB to assess whether fish species in the river Meuse are restricted in their abundance and distribution by the lack of appropriate spawning habitat. The area studied comprises the Dutch part of the river between Eijsden and Hedel, including old river arms and former gravel pits connected with the main stream. Not included in the study is the Grensmaas, a non-canalised stretch of the river. A total of 21 fish species were selected, whose habitat requirements regarding spawning and growth were collected by a literature survey. The assessment was made by relating habitat-associated factors (water depth, rate of flow, substratum, macrophytes) with fish-specific requirements on spawning and growth. Thus it was possible to assess per river section of 100 meters length its potential suitability as spawning and nursery area for 17 species. It was concluded that no potential spawning and nursery areas are available for barbel (Barbus barbus), chub (Leuciscus cephalus), nose carp (Chondrostoma nasus) and dace (Leuciscus leuciscus). The presence of these species in the study area can be explained by migration out of the Grensmaas. Only on 1.5 % of the total amount of river sections macrophytes are present, which obviously limits the possibilities for the phytophilic species pike (Esox lucius), tench (Tinca tinca), crucian carp (Carassius carassius), carp (Cyprinus carpio), bitterling (Rhode us sericeus amarus), white bream (Blicca bjoerkna) and rudd (Scardinius erythrophthalmus). For ide (Leuciscus idus), gudgeon (Gobio gobio), bleak (Alburnus alburnus), perch (Perca fluviatilis), pikeperch (Stizostedion hicioperca) and ruffe (Gymnocephalus cernua) potential spawning and nursery areas are abundantly present.
Reproduction of Fish in the Lower River Rhine and Connected Gravel-Pit Lakes
Authors: Staas S. , Neumann D.
Published: May 2018

The ocurrence of 0+-aged fish was observed during 1992 in different habitats of the Lower River Rhine (km 815-856) and in two gravel-pit lakes connected with the main stream. In both waters successful reproduction was established by early developmental stages of a large number of resident fish species. The species composition in both riverine and lake habitats was similar. In the gravel-pit lakes, fry of all species was much more abundant than in the River Rhine. Thus, the lentic waters of gravel-pit lakes connected with the River Rhine represent highly productive spawning and nursery areas even for rheophilous species of fish, so that they may be of great importance for the recruitment of the River Rhine' s fish populations.
Abatement Strategies in the Odra River Basin
Authors: Soldán P. , Švrcula J. , Ibrekk H. O. , Källqvist T.
Published: May 2018

The Odra (Oder) River flows from the Czech Republic through Poland to the Baltic Sea. Surface water as well as groundwater in the Odra River Basin is heavily polluted, especially in the Ostrava industrial region and its surroundings. The high level of pollution causes considerable impacts on human health and ecology. There is a definite need to develop sound abatement strategies to achieve long term objectives of reducing the deterioration of the environment and to restore the ecological balance in the surface water. This poster presents several related studies and focuses on the Czech-Norwegian one - “Abatement Strategies in the Odra River Basin”.
The Gemenc Floodplain Rehabilitation Project: A Policy Analysis for the Rehabilitation of a Danube Floodplain, Hungary
Authors: Marchand M. , Marteijn E. C. L. , Pedroli G. B. M. , van Velzen E. , Bakonyi P.
Published: May 2018

In 1992 the Hungarian Ministry of Transport, Communication and Water and the Ministry of Environment and Regional Policy, sponsored by the Dutch Government, commissioned a combination of Dutch and Hungarian institutes to execute a study into the possibilities for the rehabilitation of the Gemenc floodplain. It was agreed that the study would focus on the water -management of the area, but nevertheless take into account the wider scope of other management areas and interests such as the forestry, hunting, fisheries and recreation as well. The study used a policy analysis approach for formulating and analyzing three different alternatives. The results showed that rehabilitation of the Gemenc area has a good perspective, especially when the most promising elements from each of the alternatives are combined.