bluuebunny/crossref_metadata_2025 huggingface dataset:
APPLIED OFF-LINE EXPERT SYSTEM FOR EFFLUENT, OPERATIONAL AND TECHNICAL PROBLEMS OF WASTE WATER TREATMENT PLANTS
Authors: Ladiges Gösta , Kayser Rolf
Published: May 2018

An off-line expel1 system has been developed and implemented at a nutrient removing waste water treatment plant to provide the operators with knowledge required to run their plant. The system can be started at occurring problems, and for the choice of setpoints for the operation of the plant. It contains knowledge bases for various effluent waste water and technical problems, combining facts and relationships for different chemical, biological and technical processes with models and algorithms. This enables the system to assess situations and give proper advice as well based on facts, experience and calculations.

The system is built on a personal computer, and works with a Windows user interface that has been developed in intense co-operation with the plant operators.
NUMERICAL MODELLING AND MEASUREMENT IN A TEST SECONDARY SETTLING TANK
Authors: Dahl C. , Larsen T. , Petersen O.
Published: May 2018

A numerical model and measurements of flow and settling in activated sludge suspension is presented. The numerical model is an attempt to describe the complex and interrelated hydraulic and sedimentation phenomena by describing the turbulent flow field and the transport/dispersion of suspended sludge. Phenomena such as free and hindered settling and the Bingham plastic characteristic of activated sludge suspensions are included in the numerical model.

Further characterisation and test tank experiments are described. The characterisation experiments were designed to measure calibration parameters for model description of settling and density differences. In the test tank experiments, flow velocities and suspended sludge concentrations were measured with different tank inlet geometry and hydraulic and sludge loads. The test tank experiments provided results for the calibration of the numerical model and for comparing measured and calculated results.

The numerical model could, fairly accurately, predict the measured results and both the measured and calculated results showed a flow field pattern identical to the flow fields in full-scale secondary settling tanks. A specific calibration of the Bingham plastic characteristic was needed and further knowledge of activated sludge suspension rheology will be necessary to improve the numerical model.
Results of an International Plankton Investigation on the River Rhine
Authors: Tubbing D. (G.) M. J. , Admiraal W. , Backhaus D. , Friedrich G. , de Ruyter van Steveninck E. D. , Müller D. , Keller I.
Published: May 2018

Quantitative plankton observations have been carried out in the River Rhine from Lake Constance to the North Sea as part of an ecological monitoring programme, initiated to provide a baseline for evaluating measures taken under the “Rhine Action Programme”. The phyto- and Zooplankton monitoring, carried out in 1990 is the first concerted programme covering the 1000 km long reach of the river below Lake Constance. Seasonal observations at 20 fixed stations along the river were carried out by different institutes; this required calibration of methods. In the upper Rhine the sparse population of phyto-plankton (< 5 µg chlorophyll-a l-1) was dominated by various groups of algae, i.e. Cryptop-hyceae, Bacillariophyceae, Chlorophyceae and Cyanophyceae. Downstream, the phyto-plankton density increased gradually, while Bacillariophyceae tended to dominate. The high densities found in the lower R. Rhine represented only a few species of centric Bacillariophyceae and Chlorophyceae. The dense blooms of phytoplankton in the lower R. Rhine are triggered by the input of phytoplankton from the upper reaches and tributaries, and are stimulated by large inputs of nutrients. These blooms are accompanied by blooms of Zooplankton, especially rotifers, Dreissena polymorpha larvae and, in the lower Rhine, nauplii larvae. The species composition and biomass of plankton in the R. Rhine vary strongly during the year but also between years, as indicated for the period 1980-1990. However, the information at the species level needs further elaboration to allow interpretation of long-term trends. Notably, the input by tributaries should be included. To assess these long-term trends we recommend supplementing the large-scale biological inventory, as planned for the years 1995 and 2000, with plankton observations in the years between and investigating the relationship between the benthic and pelagic communities of the river.
THE DETERMINATION OF ANAEROBIC BIODEGRADABILITY OF PHARMACEUTICAL WASTES BY METHANOGENIC ACTIVITY TESTS
Authors: Zábranská J. , Jenícek P. , Dohányos M.
Published: May 2018

Methanogenic activity tests were used for the determination of anaerobic biodegradability of some concentrated wastes from the pharmaceutical industry - waste biomass from threonine production, mycelium after penicillium extraction, and excess activated sludge from the treatment of other pharmaceutical wastewaters. The tests were performed in 120 ml vials for each of the wastes ru1d for a mixture of the wastes in a real ratio. The mixture was tested at a wide range of initial biomass loading (1.15-8.8 gCOD/gVSS). The anaerobic biodegradability of the threonine biomass, the mycelium and the activated sludge was determined as 81.3%, 94.3% ru1d 44.4% respectively, and the average biodegradability of the mixture as 85.8%. Retention times needed for an 80% degradation efficiency were evaluated and used as a proposal for the starting-up biomass loading rate of the continuous reactor operation. An optimum substrate concentration without an inhibition effect was estimated and a specific methane yield for each waste; and for the mixture determined.
Prediction of Sediment Quality in Catchment Areas of the River Rhine: Operation and Use of the Horizon Model
Authors: Mol G. A. J. , Benoist A. P.
Published: May 2018

Suspended matter and sediments in the catchment areas of European rivers are often highly polluted. A forecast of sediment quality in relation to discharges is of importance in formulating policy pertaining to emission reduction and sediment sanitation. The model Horizon has been developed to predict the sediment quality in the long term under various emission reducing scenarios. The model schematics consist of a description of the Rhine, the Meuse and the large lakes and basins in The Netherlands.

The model calculates the concentration of eight inorganic and five organic micro pollutants in surface water, suspended matter and the sediment under the influence of processes such as sorption, evaporation, degradation, sedimentation, resuspension and burial. The principles underlying the model, the modelled pollutants, the schematics and the modelled physical/chemical processes are briefly discussed. The model input, calibration, validation and model errors follow. The predictions show that emission reductions more far reaching than the Rhine Action Programme (RAP) are needed to meet the Quality Objective 2000,set out in the Dutch National Policy Document on Water Management.
Assessment of River Water Quality by Test Filters in the View of Drinking Water Catchment
Authors: Mälzer Hans-Joachim , Gimbel Rolf
Published: May 2018

In the years 1985-1987, test filters have been used to determine the DOC- and AOX-concentrations and the loads of water-works-relevant and drinking-water-relevant organic constituents in the rivers Rhine and Ruhr. The constituents determined by AOX have been found to be not drinking-water-relevant. The input of water-works-relevant DOC and AOX mainly could be put down to diffuse sources.
Modelling Foodweb Accumulation of Cadmium in Sedimentation Areas of the Rhine Delta
Authors: Kramer P. R. G. , Traas Th P. , Aldenberg T. , de Vries M. B.
Published: May 2018

An integrated approach concerning the causality chain of emission, distribution and effects of toxicants was chosen to analyze the influence of pollution and the impact of historical and future measures in the Rhine basin. All major sources have been quantified and the distribution of nutrients and toxicants is determined by means of a dynamic model. A contaminant accumulation model is linked to this water quality model in order to assess the ecological effects of the compounds in specific areas. This modelling framework is used to analyze effects of cadmium on the foodweb found in Rhine sedimentation areas. Model predictions show that No Observed Effect Concentration (NOEC) levels for cadmium in algae and small molluscs are not exceeded.
Evaluation and Avoidance of False Alarm by Controlling Rhine Water with Continuously Working Biotests
Authors: Puzicha H.
Published: May 2018

Effluents from point sources (industries, communities) and diffuse inputs introduce pollutants into the water of the river Rhine and cause a basic contaminant load. The aim is to establish a biological warning system to detect increased toxicity in addition to the already existing chemical-physical monitoring system. To cover a wide range of biocides, continuous working biotests at different trophic levels (bacteria, algae, mussels, water fleas, fishes) have been developed and proved. These are checked out for sensitivity against toxicants, reaction time, validity of data and practical handling under field conditions at the river. Test-specific appropriate methods are found to differentiate between the normal range of variation and true alarm signals.
Development, Testing and Implementation of Automated Biotests for the Monitoring of the River Rhine, Demonstrated by Bacteria and Algae Tests
Authors: Schmitz P. , Krebs F. , Irmer U.
Published: May 2018

A joint research project for the development, testing and implementation of automated biotests, capable of rapidly detecting acutely toxic water conditions of the River Rhine, was carried out by several administrative and scientific institutions in Germany. Automated biomonitors working with the test organisms bacteria, algae, water fleas, mussels, and fishes were tested and compared with respect to their sensitivity, reliability, and practical handling under field conditions. Field trials with atrazine and sodium pentachlorophenolate as toxicants were performed on the River Rhine. Threshold values and LOEC-values (Lowest observed effect concentration) were determined to compare the test specific sensitivity of the test systems. From 1990 to 1992 various biomonitors were tested in monitoring stations on the river Rhine and in a mobile laboratory container on the rivers Rhine and Main. Results of bacteria and algae tests are presented.
Ecological Recovery of the River Meuse in The Netherlands
Authors: Silva W. , Kerkhofs M. J. J.
Published: May 2018

A stretch of the River Meuse in The Netherlands is planned to be restored by means of channel widening and lowering of the floodplains. The morphological, hydrological and ecological consequences of the proposed actions are presented.
Ecological Models for River Floodplain Rehabilitation
Authors: Duel H. , Denneman W. D. , Kwakernaak C.
Published: May 2018

In The Netherlands, projects have been started by the government concerning ecological rehabilitation of rivers and river floodplains. Hydrological, morphological and ecological models are indispensable tools to river basin management. In this paper a cluster of models is presented which have been used to predict and assess the effectivity of measures on improving the environmental quality and the ecological rehabilitation of the floodplains. The cluster of models consists of a simulation model for riparian vegetation development, habitat suitability evaluation models and an expert system concerning the contamination of river habitats and its ecological impact. This approach will result in an integrated ecological, environmental and water management in order to realize the ecological objectives for the rivers in The Netherlands.
WASTEWATER TREATMENT PLANT OPERATION COSTS
Authors: Balmér Peter , Mattsson Bengt
Published: May 2018

Operation and maintenance costs have been compiled for 20 wastewater treatment plants in the range of 7 000 to 650 000 population equivalents. Great effort has been made to exclude the effects of local conditions on the costs. Data on energy and chemical consumption and manpower are given as well as the total operating costs and the distribution of manpower, energy, chemical and other costs. The results show that costs for manpower and electricity as well as total costs on a per capita basis decrease with increasing plant size. The variation between individual plants is, however, large even when differences in local conditions are accounted for.
Submerged Macrophyte Control Using Plastic Blankets
Authors: Carter D. R. , Carter S. , Allen J. L.
Published: May 2018

Penrith Lakes Scheme is concerned with the rehabilitation of gravel pits to create a system of large recreational lakes. A potential submerged macrophyte problem has been identified in an existing man-made lake.

The need to control the macrophytes is dependent on the proposed end use of the lakes and the potential area of invasion.

A variety of control options were assessed. Plastic blankets were tested to determine their effectiveness in controlling macrophyte growth specifically in swimming and boat access areas. Comparisons of clear, black and black woven blankets were conducted. Experiments revealed that 90% of the plants under the black and black woven blankets died within six weeks. Under clear blankets plants were reduced by between 20%-90%.

Analysis showed that significant interactions occurred between sites and treatments and times, from which it can be inferred that none are independent of each other. Success in the reduction of macrophytes appears dependent on such factors as plant species, sediment accumulation and light reduction.
Carcoar Wetland – A Wetland System for River Nutrient Removal
Authors: White G. C. , Smalls I. C. , Bek P. A.
Published: May 2018

During December, 1991 the NSW Department of Water Resources commenced construction of an artificial wetland at the upstream end of Carcoar Dam near Blayney in central western NSW. The principal function of the wetland is to reduce nutrient inputs, especially phosphorus, from the Belubula River into Carcoar storage and consequently lower the incidence of blue-green algal blooms which occur most summers.

The wetland is a multi-faceted project involving substantial research and community involvement. Construction of the wetland weir and levees was completed during April, 1992. Stage one of the wetland planting program ran from October to December, 1992 with stage two scheduled for the same period in 1993. The wetland will not be operational until December, 1993. However, even at this early point in the project, significant experience has been gained in design, construction, planting and establishment of comprehensive community involvement programs for large constructed wetlands on the flood plain.

This paper outlines the background to the wetland, the design of the wetland system and its construction primarily as a nutrient removal mechanism in the Belubula River. The paper also outlines the direction of research undertaken and the role and nature of community involvement in various aspects of the project.
FAST-MODE REAL-TIME SIMULATOR FOR THE WASTEWATER TREATMENT PROCESS
Authors: Metzger Mieczyslaw
Published: May 2018

Process connected simulation of a process is very useful for optimal decision making. The problem of computer aided operator support in the case of a sudden augmentation of cyanide concentration in the inlet flow of a big industrial wastewater treatment plant is presented in the work. By using simulation experiments the operator of the process may check the consequences of the operating control strategies before the emergency in the real-world process occurs.
MODELLING AND CONTROL OF ACTIV ATED SLUDGE PLANTS ON THE BASIS OF RESPIROMETRY
Authors: Brouwer H. , Klapwijk A. , Keesman K. J.
Published: May 2018

In this paper. development of a cODlIol system for the activated sludge plant of Quest International Naarden BV is presented. The control system is based on on-line measurements of the actual respiration rate in the carrousel. From model sim ulations we conclude that overloading can be prevented by manipulating the wastewater flow rate. Energy can be saved. A day/night control of the aerators will result in energy cost savings between 11 and 21 %.
Inventory of Constructed Wetlands in the United States
Authors: Brown Donald S. , Reed Sherwood C.
Published: May 2018

During 1990 and 1991 the U.S. Environmental Protection Agency (EPA) sponsored an effort to identify existing and planned constructed wetlands in the U.S., and to collect readily available information from operating systems. In addition to inquiries by telephone and mail, the effort included site visits to over 20 operating subsurface flow constructed wetlands. The inventory documented the presence of over 150 constructed wetland systems for wastewater treatment, including both free water surface (FWS) and subsurface flow (SF) systems. The majority of the systems identified were SF systems for treating municipal wastewater. FWS systems were separated into three groups based on the design level of effluent water quality. SF systems were separated into three groups based on the basic design approach. The inventory indicated that neither between nor within these groups was there consensus regarding basic hydraulic and engineering design criteria, system configuration, or any other aspect, such as type of vegetation, size and type of media, or pretreatment. Information on location, type of system, design approach, hydraulic and organic loading rates, costs, and other aspects is presented. Information gathered and "lessons learned" from the site visits are presented. Insufficient oxygen for nitrification appears to be a problem for both FWS and SF systems. Insufficient hydraulic design appears to be a problem for SF systems.
An analysis of wastewater treatment strategies for Eastern and Central Europe
Authors: Henze Mogens , Ødegaard Hallvard
Published: May 2018

Wastewater management in Central and Eastern Europe is a choice between two basic alternatives. One is to build a limited number of high efficiency treatment plants and the other to build a bigger number of plants with less efficiency. The paper discusses these options, based on technical and economical considerations. The conclusion is that a stepwise development, with chemical precipitation as the first step and biological treatment as the second step, in general is the recommendable solution.
A survey of organic contaminants in drinking water, mineral water and natural water in Eastern and Central European countries
Authors: Kostyál E. , Saski E. , Salkinoja-Salonen M.
Published: May 2018

Monitoring of organic pollution is becoming more and more important, because the toxicity of many commonly used organic chemicals such as solvents, pesticides and their metabolites are similar to that of toxic heavy metals. In this study we analyzed the organic sum parameters, adsorbable organic halogen and total organic carbon, in drinking, mineral, river and lake waters collected from 20 countries in Europe from 117 locations. Analyses were done according to the standard methods. We found that the East European and Hungarian drinking waters contained more organic halogen and carbon than the West European ones. The mineral water wells in the North Slopes of the Caucasus Mountains in Russia are endangered, the water of some of the wells is not potable. The rivers and lakes of Europe are polluted with organic halogens mainly from multisources. To our knowledge this is the first survey of organic sum parameters in this part of Europe.
Nitrification as a source of soluble organic substrate in biological treatment
Authors: Rittmann Bruce E. , Regan John M. , Stahl David A.
Published: May 2018

In complex, multispecies populations, exchange of substrates can be an important beneficial interaction. Prior experimental and theoretical work has led to the hypothesis that the formation of soluble microbial products (SMP) by nitrifying bacteria can provide a supplementary organic substrate for heterotrophic bacteria, thereby augmenting their accumulation and stability, especially when inputs of organic substrates are low. In this study, chemostat experiments carried out with a NO2−-oxidizing strain (Nitrobacter sp.) and an NH4+-oxidizing strain (Nitrosomonas europaea) demonstrated that both nitrifiers produce SMP that can support heterotrophic bacteria. The first evidence was the presence of significant concentrations of soluble COD in the chemostat effluent, even though the influent was free of organic compounds. Second, a small heterotrophic population was maintained, apparently through utilization of the nitrifier-produced SMP. A preliminary kinetic analysis suggested that SMP kinetic parameters can be adapted from parameters measured for heterotrophs.
Primary fermentation of soluble and particulate organic matter for wastewater treatment
Authors: GonÇalves Ricardo Françi , Charlier Anne Catherine , Sammut François
Published: May 2018

A new reactor based on upflow sludge blanket technology (USB) for fermentation of both the particulate and soluble fractions of domestic wastewater is presented. The process is fed with the total wastewater flow, and carries out suspended solids (SS) retention, fermentation and clarification of the fermented effluent in a single reactor. The study was carried out using pilot scale reactors, under six different operating conditions with regards to hydraulic load (hydraulic retention time, HRT, varying between 1.1 and 4.3 hours) and at a constant temperature (20 ± 1°C).

With regards to primary treatment, the process has been shown to ensure low SS residuals in the fermented effluent under all operating conditions tested. Very low residuals, with an average below 50 mg SS/l, were obtained with an upflow velocity of between 0.75 and 0.9 m/h. These trials have also highlighted the important role played by the adsorption of particulate organic matter on the biological flocs of the sludge blanket in the elimination of SS.

Fermentation efficiencies are superior to those of existing fermenters, the results clearly proving that a majority of the volatile fatty acids produced originate from the soluble fraction of the wastewater. Under the optimum conditions tested, with an HRT = 2.8 hours, 0.17 mg HAc/mg total COD are produced, over 60% of which is generated by the fermentation of the influent soluble organic matter. Under these operating conditions, maximum solubilisation of the particulate fraction has been estimated at 0.13 mg of filtered COD/mg particulate COD (total COD-filtered COD).
Induction method of excess phosphate accumulation for phosphate removing bacteria isolated from anaerobic/aerobic activated sludge
Authors: Ubukata Y. , Takii S.
Published: May 2018

Many bacteria considered to be phosphate removing bacteria (PRB) have previously been isolated from phosphate removing activated sludge (PRAS). However, these bacteria have never exhibited the typical function of PRB which take up excessive phosphate (P) in aerobic conditions and release P with a concomitant uptake of organic substrates in anaerobic conditions. We hypothesized that the enzyme system responsible for excess P accumulation (EPA) should be inducible, because PRB can take up organic substrates anaerobically in spite of being obligate aerobes. Therefore, PRB cells grown aerobically have to be additionally treated with alternating anaerobic incubation with organic substrates and aerobic incubation without organic substrates to exhibit the above typical function. We succeeded in the first isolation of a strain of true PRB by this induction method. The isolate is a Gram-positive coccus and its generation time is approximately 12 hours. The anaerobic/aerobic incubation cycle was required at least two times (2 days) to induce the ability of EPA for PRB. The velocity of P removal in the aerobic phase was decreased to approximately half by the existence of organic substrates. Therefore, it is recommended that organic compounds be removed during the anaerobic phase in PRAS systems.
Interactions between biological and physico-chemical mechanisms in biological phosphate elimination
Authors: Witt P. Ch. , Grabowski F. , Hahn H. H.
Published: May 2018

By combining a sequential P-extraction with batch experiments the presented investigations clarify the mechanisms of (enhanced) biological phosphate elimination and especially to answer the following questions: are any physicochemical mechanisms involved in the biological phosphate elimination? are there any interactions between biological and physicochemical unit operations? If so, are these of synergistic or antagonistic nature?

The following main results were found:

Results of batch experiments:

– calcium decreases under anaerobic conditions; this indicates Ca-P-precipitation.

– magnesium increases under anaerobic conditions and decreases under aerobic conditions just as phosphate does; there is a high correlation between dissolved magnesium and dissolved phosphorus. Therefore magnesium seems to participate in biological mechanisms (counter-ion of polyphosphates).

– concerning the total P elimination efficiency both unit processes seem to have a synergistic effect (biologically mediated P-precipitation).

Results of P-fractionations:

– there is a certain amount of particulate physicochemically bound phosphorus, which should not be neglected.

– although the biologically bound phosphorus dominates (as a rule), this amount depends on the concentration of the readily biodegradable COD significantly.

– during the cyclic P-release/P-uptake not only transitions from soluble phase to particulate phase but alsotransfers within the particulate phase take place.

– the total P-content of the activated sludge and the sum of the Non Reactive Phosphorus-fractions (without Phase Separation-Non Reactive Phosphorus) seem to be suitable to characterize the capacity of the biological phosphate elimination.

Conclusions:

Physicochemical mechanisms take part in the enhanced biological phosphate removal and they should be taken into consideration. Therefore they should be included into the deterministic model development.
Circulation of phosphorus in a system with biological p-removal and sludge digestion
Authors: Nyberg U. , Aspegren H. , Andersson B. , Elberg Jorgensen P. , la Cour Jansen J.
Published: May 2018

Pilot plant studies of enhanced biological phosphorus removal (EBPR) based on an activated sludge process have been conducted at the Sjölunda plant since 1986. One of the main questions with respect to this process alternative is how the sludge treatment system is to be operated. In order to study the release of phosphorus from an EBPR sludge during anaerobic digestion, a study was performed with manually operated laboratory reactors. Fractionation procedures were used in order to characterize the sludge with respect to phosphorus. The influent wastewater quality determines the release and precipitation of phosphorus during anaerobic digestion. The potential for precipitation is in principle determined by the amount of metals in the influent wastewater which are removed with the wasted sludge. At the Sjölunda plant, a process scheme based on an EBPR process and anaerobic digestion requires that the circulation of phosphorus is prevented by means of addition of chemicals in order to acquire a phosphorus concentration of around 0.5 – 1 mg P/l in the secondary effluent.
Biological nitrogen and phosphorus removal in an anaerobic/anoxic sequencing batch reactor with separated biofilm nitrification
Authors: Bortone G. , Malaspina F. , Stante L. , Tilche A.
Published: May 2018

An Anaerobic/Anoxic Sequencing Batch Reactor (A/A SBR) with separated batch biofilm nitrification was tested for nutrient removal against a five step Anaerobic-anoxic/Oxic SBR (A/O SBR). Piggery wastewater, particularly challenging for its low COD/N ratio, was used as feed. After feeding, the A/A SBR ran under anaerobic conditions for organic carbon sequestering and phosphorus removal. A settling phase was allowed to separate an ammonia-rich supernatant to be nitrified in a external biofilm reactor. The nitrified effluent returned to the A/A SBR where nitrates were removed, being used as final electron acceptors for luxury P-uptake and organic carbon oxidation. A/A SBR showed very good N and P removal capacities with excellent sludge settling properties. On the other hand, organic carbon removal efficiency with nitrate was lower than with oxygen. Batch biofilm nitrification was very effective, with very high nitrification rates. Presence of poly-P bacteria in the A/A SBR sludge was assessed through microscopic observation and from the high cellular poly-phosphate content.
Kinetic model for the biotransformation of tetrachloroethylene in groundwater
Authors: Ninomiya K. , Sakai M. , Ohba E. , Kashiwagi N.
Published: May 2018

The biotransformation of tetrachloroethylene (PCE) to trichloroethylene (TCE) and then to cis-1,2-dichloroethylene (cis-DCE) under an anaerobic condition was studied using static soil microcosms. The kinetics of the biotransformation could be well approximated by the consecutive first-order reaction model, PCE →k1 TCE →k2 cis-DCE

This model implied that the total amount of the above three compounds was always constant and was equal to the initial amount of PCE, even if the amount of each compound changed with time. Based on this stoichiometric relationship, two indices to characterize groundwater contamination with PCE were derived. The first was the total contamination level which was defined by the total molarity of the three compounds. The second was the degradation level which was defined by the total molar percentage of the products (TCE+DCE). These indices enabled us to evaluate the initial molarity of the pollutant PCE and the degree of the degradation. The kinetic theory also provided a useful rule such that the same time-concentration profile was obtained for the same ratio of the kinetic constants k2/k1, even if the scale of time changed. This rule enabled us to estimate the ratio of the kinetic constants, which suggested environmental fate of groundwater, from observed molarities of the three compounds.
Sludge Retention Times Distribution in Clarifier: A Key Point for Population Dynamic and Nutrients Removal Control
Authors: Audic J. M. , Fayoux Ch , Lesty Y. , Brisset P.
Published: May 2018

Experiments were carried out on full scale clarifiers. Two types of clarifiers were studied, circular scraper-type and radial suction tubes clarifiers. Sludge tracing experiments were made with radioactive gold.

For the first type of clarifier, the results obtained show a short circuit concerning 10 to 30% of the sludge and a large distribution of the remaining sludge arrivals materialized by a succession of peaks that appear with increasing delay. Depending on cases studied, 40 to 50% of the sludge remained more than 5 hours in the system.

For the suction clarifier, a perfect sludge distribution with time was observed for thin sludge bed (90% of the sludge recycled within 2 hours), but this result is rapidly affected by an increase of the sludge bed depth (60% within 5 hours).
Counting Bacteria of Selected Metabolic Groups in Activated Sludge – An Assessment of Methods
Authors: Schade M. , Lemmer H.
Published: May 2018

For counting bacteria of selected metabolic groups in activated sludge several methods such as the MPN-method, the pour plate method, the surface plate method, and the membrane filter technique are available. Population densities of heterotrophic saprophytes were assessed with the MPN-method, the pour plate and the surface plate method. The surface plate method yielded higher bacterial counts compared to the pour plate method. The MPN-method is not suitable because of the ambiguity of results leading to large statistical errors. The membrane filter technique yielded significantly higher counts of ammonifying bacteria compared to the MPN-method. The population density of nitrate reducing bacteria was estimated by the MPN-method and the membrane filter technique. Higher counts were found with the MPN-method. However, both methods are not satisfactory for determining nitrate reducers. Methodological problems are discussed. For counting coliform bacteria the MPN-method has to be preferred over plate count methods for MacConkey agar-medium selects aeromonads instead of enterobacteria.
Biomass Characterization in a Nitrification-Denitrification Biological Enhanced Phosphorus Removal (NDBEPR) Plant during Start-Up and Subsequent Periods of Good and Poor Phosphorus Removal
Authors: Lindrea K. C. , Pigdon S. P. , Boyd B. , Lockwood G. A.
Published: May 2018

During commissioning and process stabilization of a NDBEPR plant at Bendigo intracellular distribution and movement of phosphorus, K+, Mg2+ and Ca2+ was followed to establish the nature of biomass development. The system was also monitored at the end of a period of breakdown of the BEPR process and during its return to phosphorus removal. Phosphorus (P) and Mg2+ distribution in the biomass were closely related during all phases of plant operation, and laboratory trials indicated that the poor performance of the full-scale plant was associated with seasonal reduction in influent Mg2+. Laboratory scale trials produced a similar effect when the influent Mg2+ was limited to concentrations much lower than those experienced in the full scale plant, but only after the Mg2+ and P reserves in the biomass were depleted. The distribution of P, K+, Mg2+ and Ca2+ in the biomass from the full scale plant was similar to that seen in the laboratory trials when cations in the feed were severely limited and recovery of the full scale plant also closely matched that of the laboratory scale system.
Oxidative pathways in the degradation of triazine herbicides: a mechanistic approach
Authors: Bolzacchini Ezio , Brambilla Anna , Orlandi Marco , Polesello Stefano , Rindone Bruno
Published: May 2018

Studies about the chemical reactivity of compounds widely used in the environment are needed. The chemical reactivity of triazines toward oxidants was tested in the laboratory with cerium(IV) ammonium nitrate and ozone. Simazine, atrazine and terbutylazine were tested. The oxidative N-dealkylation occurred both with cerium ammonium nitrate and with ozone at acidic pH. The N-de-ethylation was invariably preferred to the N-dealkylation reaction. A degradation pathway for triazine herbicides is suggested. The kinetics of the oxidation of these triazines with ozone at pH 3 and the kinetics of the saturation of the solution with ozone have been evaluated. These data may be useful for the prediction of the persistency of these compounds in the environment.
Effects of Operation Conditions on Advanced COD Removal in Activated Sludge Systems
Authors: Franta J. , Wilderer P. A. , Miksch K. , Sykora V.
Published: May 2018

Sequencing Batch Reactor (SBR) experiments have been conducted to study factors affecting composition and concentration of residual organics in the effluent of biological wastewater treatment plants. Wastewater discharged by a papermill was used as a reference. First results indicate that sludge age plays an important role when industrial wastewaters are to be treated. Increase of the sludge age led to elimination of key halogenated compounds in the effluent, although the effluent COD often remained hardly changed. Of importance is also the duration of the starvation period during each cycle. To maintain high substrate removal efficiency it is necessary to extend the duration of the aeration phase until the enzyme activity has been reduced to the background level. It was observed that the enzyme activity remains high even when the respiration rate had reached the level of endogenous respiration. High treatment efficiency can only be maintained if the bacteria are supplied with feed, and then exposed to starvation conditions on a periodic basis.
Status and Direction of Waste Minimization in the Chemical and Petrochemical Industries
Authors: Englande A. J.
Published: May 2018

This paper presents an evaluation of the status and direction of toxic/hazardous waste reduction in the chemical and petrochemical industries from an international perspective. Pertinent approaches, experiences and trends are described. Industrial waste management has evolved from an “end-of-pipe” treatment mentality to source reduction as the preferred option. It is generally agreed that the Chemical/Petrochemical Industries generate more hazardous and toxic waste than any other industrial sector. Also because of the large quantities of materials and energy used by these industries, significant opportunities are available for waste reduction. In almost all cases costs savings have resulted, many of which are significant. The importance of pollution prevention by “clean technologies” instead of remediation, multi-media considerations and the significance of product life-cycle assessment in pollution prevention programs is stressed. Examples are provided which demonstrate, that a proactive approach by DOW, E.I. DuPONT, AMOCO, 3M Corp., CIBA-GEIGY and others is now becoming the norm.

From an international policy perspective, important commonalities and differences in strategy and efforts for toxics/hazardous waste management exist. Much can be learned by the mistakes and solutions between cultures and countries. Much progress has been made in protection of public health and the environment - but much remains to be done. This paper is intended to provide a stimulus for discussion aimed at optimizing future waste minimization activities in the chemical and petrochemical industries.
The Impact of Industrial Waste on Venezuelan Marine Water
Authors: Roberts Frank , Guarino Carmen , Arias Marlene
Published: May 2018

The Puerto Cabello-Morón coastal area of Venezuela is an ideal location for industries that require large land areas, water, marine transportation, minimum habitation, cooling water and waste disposal options both on land and sea. However, mercury spills between 1957 and 1976 have produced concern in the entire coastal zone from Puerto Cabello to Chichiriviche (70 kilometres of coastline) and the National Park area.

MARNR, the Ministry of Environment and Renewable Natural Resources in Venezuelarequested Bechtel to evaluate the impact of the majorindustries in this area.

Bechtel's investigation included chemical, biological and toxicity analysis of the rivers, and key locations along the coast and the sea and industrial effluents. In addition, a literature search was made of any previous work to assist in the evaluation and recommendations for any necessary corrective action.

The investigation identified negative impacts due to the effluent discharge of the major industries. Recommendations for wastewater management included installation of wastewater stabilization lagoons for treatment and ocean outfalls for final effluent disposal.
Anaerobic digestion of OFMSW (organic fraction of municipal solid waste) and BNR (biological nutrient removal) processes: a possible integration – preliminary results
Authors: Cecchi F. , Battistoni P. , Pavan P. , Fava G. , Mata-Alvarez J.
Published: May 2018

The paper presents preliminary experimental results which aim to demonstrate the possibility of producing easily biodegradable carbon from a two phase anaerobic digestion process for a biological nutrient removal process. Crystallization of phosphorus into struvite from the liquor of the digested flow is the second goal of the process studied. With this integrated process approach it is possible to double the amount of readily biodegradable COD entering the wastewater works by sewers and to recover up to 70% of phosphorus from the digested flow as struvite without using little amount of chemicals. Struvite granules are useful for agricultural purposes.
Calibration of a compressive gravity thickening model from a single batch settling curve
Authors: Cacossa Kenneth F. , Vaccari David A.
Published: May 2018

A compressive gravity thickening model (Kos and Adrian, 1974; Kos, 1978) was calibrated from a single batch settling curve. This model was originally formulated in terms of the total suspended solids concentration, C, the dynamic pressure gradient, ∂P/∂z, and the gradient corresponding to the compressive yield strength, ∂σy/∂z. Fitch (1975) demonstrated that the model could be formulated in terms of C and the solids concentration gradient, ∂C/∂z. Utilizing this formulation the model was calibrated with data generated from elementary quantitative analysis of the steady-state conditions attained in continuous thickening experiments (Vaccari, 1984; Vaccari and Uchrin, 1989). In this investigation the model was calibrated from a single batch settling curve. This was done using the down-hill simplex optimization method proposed by Nelder and Mead (1965) in a curve-fitting capacity. The optimization routine adjusted the model coefficients in order to reduce the discrepancy between the simulated results of the model and the corresponding experimental batch settling data. When calibrated by this method the model was found to accurately predict experimental continuous thickening behavior observed for the sludge.
The Sewage Works Manager – An Industrialist's Friend or Foe?
Authors: Matthews P.
Published: May 2018

Many industrial effluents are discharged to public sewers and are treated in admixture with domestic sewage. The treatment works provides a service, therefore, to industry. The treatment works manager is under the constraint of environmental restrictions on effluent and sludge disposal and the constraint of keeping costs down. Inevitably these constraints are passed onto the industrial discharger. It is very important that the industrialist is treated like a customer and understands the reasons for the constraints. The paper reviews the nature of the services and constraints. It draws on the author's experience in providing a regulation and treatment service to over 2000 industrialists.
Environmental Soil and Ground Water Assessment Using High Resolution Passive Soil-Gas Samplers - Petrex Method: Methodology and Results of a Case Study Performed in Brazil
Authors: Gomes D. C. , Alarsa M. , Salvador M. C. , Kupferschmid C.
Published: May 2018

The PETREX Passive Soil Gas Technique - applied successfully to environmental projects for 10 years - is the ideal primary investigative tool for soil and groundwater contaminations, since it is rapid, easy to apply and covers large areas. It is more sensitive and cost effective than other methods (e.g. active soil gas techniques). Passive collectors combined with high-resolution mass spectrometry permit direct mid reliable identification of over 9,000 volatile (VOCs) and semi-volatile organic compounds (SVOCs). PETREX is capable of providing comprehensive problem delineation during the initial stages of the site investigation, allowing for greater cost effectiveness in the planning of remediation programs and in the selection of appropriate monitoring well locations and other methodologies which may be needed to complete the environmental evaluation. PETREX therefore finds wide use in the investigation of contaminants, in the determination of pollution sources, as well as in audits connected to real estate transactions. This paper describes a case-study developed in Brazil, showing PETREX's usefulness and its correlation with soil and groundwater contamination plumes established from traditional direct sampling methods.
Waste Minimization Promotes Biophysical Treatment of Complex Petrochemical Wastes in Israel
Authors: Lebel A. , Raveh A.
Published: May 2018

A full-scale 300 m3/day industrial waste treatment system was put into operation in a petrochemical manufacturing plant in Israel for the purpose of detoxifying its complex organic waste stream. The GPI treatment plant design incorporates an innovative waste management approach to accommodate the limited space allocated for the facility. It employs influent equalization and waste minimization techniques, in support of an advanced biophysical treatment process to accomplish a substantial reduction in the facility footprint while producing a high quality effluent. Initial performance data indicate a highly efficient organic waste reduction. COD and BOD removal surpassed 95% and 98%, respectively, over the initial two months of operation, meeting the stringent effluent discharge criteria. The system also provides effective sludge dewatering, producing 40-50% solids sludge, thereby minimizing sludge disposal costs.
Waste Incineration – The Bridge Between Today'S Capability and Future Goals
Authors: Pledger James T.
Published: May 2018

As the world-wide effort to reduce waste gains momentum, there will be a changing attitude towards waste generators. This transition will require the construction of incinerators to provide a critical link in managing the difficult wastes that remain. They must demonstrate the best available technology and quality operation. These incinerators become the bridge that allows time for the transition of world-wide manufacturing facilities to meet the environmental expectations now gaining prominence.
Is it realistic to use water hyacinth for wastewater treatment and nutrient removal in Central Europe?
Authors: Žáková Z. , Palát M. , Kocková E. , Toufar J.
Published: May 2018

The use of Eichhornia crassipes (Mart.) Solms (water hyacinth) has been tested in experimental systems in South Moravia (Czech Republic). The results of these experiments showed that the maximum rate of dry matter production and water treatment capacity during the summer period attained values which were comparable to tropical and subtropical zones. However, the vegetative period within natural conditions in South Moravia (and probably in the lowlands of the whole of Central Europe) is approximately half the time of tropical and subtropical zones and is reflected in lower total yields. The main topics of experiments performed in 1991 were: an assessment of the temperature dependence of growth and reproduction ofEichhornia crassipes in conditions prevailing in South Moravia, and the possibility of extending the growing season. The experiments used effluent from the city of Brno municipal waste water treatment plant. A strong temperature limitation was ascertained on the growth of water hyacinth. The intense growth of Eichhornia was investigated after the average daily temperature had reached 18°C. It was possible to prolong the vegetative period of water hyacinth, and treatment of the effluent, by covering experimental basins with a polyethylene shelter.
Developments in Industrial Effluent Control in the United Kingdom
Authors: Fisher T. J.
Published: May 2018

Since 1974 controls on industrial effluent dischargers in the United Kingdom have increased significantly. The Water Act 1989 transferred the Water Industry in England and Wales to the private sector and created a National Rivers Authority. A mechanism to control the input of dangerous and harmful substances into the aquatic environment was established which requires Water Service Companies (WSCs) to refer to the Secretary of State for the Environment before granting consents for discharge to public sewer.

The Environmental protection Act 1990 (EPA) further increased regulation and established the principle of Integrated Pollution Control (IPC). Operators of industrial processes listed under the Act are required to obtain authorisation from Her Majesty's Inspectorate of Pollution (HMIP) (HMIPI in Scotland) before they can operate the process.

The complexity of legislation and regulation is described and practical difficulties experienced when implementing the controls are examined, as are the relationships between the main environmental regulators together with their relative responsibilities. Also discussed are the costs associated with licensing and effluent disposal.