bluuebunny/crossref_metadata_2025 huggingface dataset:
Detection of Genotoxins in the Aquatic Environment with the Mussel Mytilus Edulis
Authors: Wrisberg M. N. , Rhemrev R.
Published: May 2018

The blue mussel, Mytilus edulis is often used in marine biomonitoring programs. In this paper two different genotoxicity tests are considered as possible indicators for genotoxic pollution in the marine environment. One is focusing on micronucleus (MN) analysis in the blood cells of mussels and the other on the detection of DNA-adducts in the whole mussel tissue. The induction of MN has been studied in short-term laboratory experiments, during which mussels were exposed to standard genotoxins or waste water. Both genotoxicity tests have been applied in a study where mussels were exposed to contaminated sediment under controlled mesocosm conditions. These studies indicate that the MN mussel test may be used as a sensitive indicator of genotoxic pollution, although the inducibility of MN in the blood cells appears to be limited and to some extent seasonally dependent. The detection of DNA-adducts is still under development, but the preliminary result seems promising for its application as a biomonitoring tool.
Mutagenioty of Ozonation Products from Humic Substances and Their Components
Authors: Matsuda H. , Yamamori H. , Sato T. , Ose Y. , Nagase H. , Kito H. , Sumida K.
Published: May 2018

Eight structural components of humic substances were ozonated. Mutagenicity was found on TA 100 with and without S9 mix for allthe ozonated components. Aldehydes, ketones and carboxylic acid were identified as the ozonation products from p-hydroxybenzal dehyde. Among these products, acetaldehyde (AA), formaldehyde (FA), glyoxal (GL), glyoxylic acid (GA) and methylglyoxal (MGL) were mutagenic compounds. The quantitative analysis of these mutagenic aldehydes was performed. GL and GA were main mutagenic products. Granular activated carbon (GAC) treatment after ozonation was performed. Most of the mutagenic aldehydes reduced, but only GL increased.
Activated Sludge Process Response to Variable Inputs of Heavy Metals
Authors: Melcer H. , Monteith H. , Nutt S. G.
Published: May 2018

Laboratory-scale activated sludge treatment systems were operated under dynamic loading conditions to investigate the non-steady state behaviour of heavy metal contaminants under controlled conditions. Four step tests were conducted in which an incremental increase in the concentrations of selected contaminants was applied to the reactor feed from background levels of about 100 µg/L to levels of about 1000 µg/L for each metal over a period of approximately three hydraulic retention times. Effluent metal concentrations rose significantly to levels of approximately 500 µg/L. They remained elevated for long periods after termination of the metal perturbations. Solids retention time (SRI) did not appear to influence metal removal efficiency over the range tested. Hydraulic retention time (HRT) effects were difficult to discern from the confounding effect of influent metal concentration.
Environmental Impact Assessment and Control of Marine Industrial Wastewater Discharges
Authors: Nyholm N.
Published: May 2018

Wastewaters from the chemical industry may contain a large number of both known/identified and unknown/not identified chemical substances, and the composition of the effluents may vary greatly from plant to plant. Usually only a minor fraction of the chemicals present are identified and adequate environmental property data may be available only for a small number of these. Effluent characterizations in terms of summary parameters are therefore necessary to complement chemical specific characterizations, but the selection of suitable summary parameters other than traditionally wastewater parameters depends on the particular effluent and the available information. The types of pollution effects to be mitigated depend on the intrinsic properties and volumes of effluent discharged as well as on the initial dilution and the specific characteristics and designated uses of the receiving water. For these reasons management decisions should be based on individual case specific environmental impact or risk assessments and simultaneous individual technical and economical evaluations of potential remedial actions (comprising cleaner technology options, wastewater treatment, and improved dilution in the receiving water). This paper presents a generalized integrated impact assessment and control strategy for marine discharges based upon Danish experiences over a 10 year period.
Impact de la desinfection de l'effluent d'une station depuration en zone cotiere mediterraneenne - The Impact of Disinfection of the Effluent of a Wastewater Treatment Plant on the Mediterranean Coast
Authors: Comes F. , Huau M.-C. , Kloninger P.
Published: May 2018

The removal of microorganisms from the wastewater of municipal treatment plants is more and more in demand in order to comply with the effluents standards required for the ecotoxicological protection of the receiving water, especially to levels of seaside resorts and shellfish breeding marine areas. Therefore, in these sensitive coastal areas close to seaside resorts, the study of the bacteriological pollution of the effluents has become a priority because of the inefficiency of the traditional wastewater treatment processes for microbic contamination. The bacterial concentration levels of the effluents are usually about 106 germs per 100 ml. The aim of a disinfection unit is to reduce these germ counts to under 2000 germs per 100 ml to comply with the natural receiving water bacterial levels and in particular where the quality of the water is required for sea-bathing.

Chlorination is commonly used in the disinfection of wastewater effluents, but it does present disadvantages such as the bactericide efficiency (global bacteria elimination rate and specific species resistivity rate) which is limited. The use and storage of chemical reagents is an operating constraint.

The UV disinfection seems to be valid and efficient without any risk of toxicity in the effluent. This technique which does not require reagents is simple to maintain at low and medium flows; it is easily automated and continuously monitored.

Firstly, this paper describes comparative results for the reduction rate of bacterial concentrations using the above mentioned two disinfection techniques : chlorination and UV. A full-scale chlorination unit has been installed at the wastewater treatment plant of Canet-en-Roussillon where the received pollution corresponds to 50000 population equivalents in summer. Two UV pilot-scale units have also been installed on site. The effluents are discharged into the river Têt, the plant is located a few hundred meters from the outfall into the Mediterranean Sea downstream from a great urban center and close to a famous seaside resort.

Secondly, a survey of the impact of wastewater disinfection on the coastal area is carried out following, in particular, the bacteriological state of the beaches. If the first step of this study is to determine the efficiency of the disinfection to improve the quality of the effluent and to obtain the levels required for a seaside resort, it is also essential, in a second step, to extend the investigation to evaluate the relative impact of the disinfection on the global quality of the natural coastal water.
Treatment of Effluent from Dredged Material Disposal Sites: Suspended Solids Removal and Nitrification
Authors: Netzband A. , Rohbrecht-Buck K.
Published: May 2018

Large quantities of wastewater containing suspended solids, heavy metals and particularly ammonium are derived when disposing of the dredged material from the Hamburg harbour. For the first time, a state-of-the-art method of purifying this wastewater comprising the following stages has been defined and realised: recirculation of transport-water in order to reduce quantities, flocculation followed by sedimentation to remove the suspended solids, and nitrification in a combination of trickling filters and rotating biological contactors. The main results of the first two years of operation are presented. Suspended solids are removed to 80% and heavy metals to between 60 and 90%; the COD is reduced from up to 250 mg/l to approx. 60 mg/l and ammonium inflow values of up to 80 mg N/l are reduced to values smaller than 2 mg N/l at temperatures above 10 °C. At 10 °C the nitrification rates reach values of up to 0.55 g NH4-N/m2 d in the trickling filter and up to 1.40 g NH4-N/m2 d in the rotating biological contactor. An expert system is used for operating the nitrification stage.
Effect of Wastewater Injection on Ground Water Quality
Authors: Legeas M. , Carré J. , Mérot Ph.
Published: May 2018

Effluents from the treatment plant of Saint Jean de Monts and Saint Hilaire de Riez have been injected into a confined ground water for twelve years. This ground water is connected with the sea. Effluent floats on the surface of the aquifer and it disperses by dilution at the freshwater/salt water interface. The aquifer acts as a direct overflow pipe. The injection of effluent has preserved the quality of waters in the coastal area and in the Breton Marsh.
Cross Media Inputs to Eastern US Watersheds and Their Significance to Estuarine Water Quality
Authors: Correll D. L. , Jordan T. E. , Weller D. E.
Published: May 2018

Extensive research on Chesapeake Bay estuary, its drainage basin, and its airshed have now demonstrated that atmospheric deposition and diffuse land discharges are the largest sources for many parameters affecting estuarine water quality. For example, phosphorus and sediments are transported to the Bay largely in overland storm flows, nitrate largely in atmospheric deposition and in ground water, many pesticides and other toxic materials in surface waters and atmospheric deposition, and silicate primarily in ground water. Concerns over point sources such as sewage treatment outfalls and industrial outfalls have led to greatly improved treatment methods, alleviating the relative magnitude of these sources. The realization of the magnitude and importance of diffuse sources has led to research on improved land use practices, including better patterns of land use in the Chesapeake Bay landscape. One example is the use of and improved management of forested riparian buffer zones in the coastal plain part of the drainage basin.
Sustainable Development Patterns: The Chesapeake Bay Region
Authors: Rogers J. W.
Published: May 2018

Those who decide how land is developed need to understand the concept of “nodes and corridors” for human development patterns as well as “nodes and corridors” for sustainable biological diversity and natural processes. Human activity has dramatically changed the landscape and has subtly altered the balance of nature. Each land use creates a host of environmental quality issues. For each choice of location development types, density, construction methods, or ways of conducting day-to-day domestic and business practices, there seems to be unintended environmental consequences. Studies have shown how land use densities and landscape patterns are fundamental to achieving sustainable environmental quality, lifestyles, and economies. Sustainable economic vitality requires sustainable environmental quality. Biologists and managers have been aware since Darwin's work on the biology of islands that a relationship exists between habitat size and its composition. Today, forests, wetlands, and other sensitive ecosystems are often “islands” in a sea of disturbed land. The patterns and sizes of these island ecosystems must be managed to prevent extinction of plants and animals and loss of functions such as those that prevent flooding and enhance water quality.
Sorption of Organic Pollutants from Vapor Phase: The Effects of Natural Solid Characteristics and Moisture Content
Authors: Shimizu Y. , Takei N. , Terashima Y.
Published: May 2018

The sorption of trichloroethylene (TCE) from vapor phase onto natural solids was investigated by batch sorption experiments. The effects of natural solid characteristics and moisture content on the sorption of TCE vapor were evaluated. As natural solids, six different US EPA soils and sediments were used. The moisture content of each natural solid was adjusted at four different values, including oven-dried condition. The linear sorption coefficients of TCE from the vapor phase (Kd’) were about one to four orders of magnitude greater than those from the aqueous phase. The Kd’ values for the oven-dried natural solids had poor correlation to the organic carbon content of natural solids. These results indicated that the sorption of TCE vapor was not controlled by the organic carbon referenced hydrophobic sorption. The Kd’ values for the oven-dried natural solids, however, correlate well with the cation exchange capacity (CEC) and swelling clay content of natural solids. The interaction of TCE molecules with the exchangeable cations on natural solid surface could be a dominant sorption mechanism. The Kd’ values decreased with increasing the moisture content of natural solids. The water on natural solid surface interferes the vapor-phase sorption of TCE onto the surface cations.
The Effect of Mixtures of Xenobiotics and Primary Electron Donor on the Anaerobic Biotransformation of High Concentrations of Chlorinated Aliphatics
Authors: Hughes J. B. , Parkin G. F.
Published: May 2018

Results are presented from experiments addressing the anaerobic biotransfoimation of high concentrations of three chlorinated aliphatics, dichloromethane (DCM), chloroform (CF), and 1,1,1-trichloroethane (TCA), when fed alone and in mixtures. Experiments were conducted to address the effect of feeding mixtures of these compounds on the transformation rates of individual components in the mixture, and to assess the effect of acetate loading rates on the extent of transformation of the chlorinated aliphatics. Feeding mixtures of chlorinated aliphatics caused decreased transformation of TCA, increased the transformation of DCM, and had mixed effects on CF transformation. The systems fed higher acetate loading rates demonstrated an increased ability to transform the chlorinated aliphatics.
A Method Development for the Routine Analytical Monitoring of Aqueous Cyanide Species
Authors: Rosentreter J. J. , Skogerboe R. K.
Published: May 2018

Utilizing a highly selective reaction between silver metal and cyanide ions, an apparatus and procedure for the analytical determination of aqueous cyanide species has been developed. The rapid analysis of free cyanide has been achieved through the use of pure silver filters as the reaction medium and atomic absorption spectroscopy as the detection method. This methodology has allowed for the quantitative detection of cyanide ions down to the sub-parts-per-billion level. By incorporating selective oxidation, kinetic equilibria, and photodissociation techniques, the silver-cyanide reaction technique has been adapted to provide a means of categorically speciating aqueous cyanide compounds. The complete system has been shown to be free from common chemical interferences, including thiocyanate. This detection system provides high speed cyanide determinations with little to no sample preparation or instrument supervision.
Toxics Management in the Chemical and Petrochemical Industries
Authors: Englande A. J. , Guarino C. F.
Published: May 2018

Findings of an international conference sponsored by the IAWPRC and Tulane University entitled, “Waste Management in the Chemical and Petrochemical Industries - Toxics Management” held 17-20 June 1991 in New Orleans, Louisiana, USA are summarized and discussed. Focus is given to the identification, assessment and control of toxics with emphasis on: legal considerations, toxicity assessment, waste minimization and innovative treatment techniques for toxic and hazardous waste liquids and residuals. Management of toxics in the chemical and petrochemical industries is developing into an interactive process between many disciplines. Evaluation procedures are becoming more complex due to a trend towards human-health-based standards for specific chemicals. Consensus among regulators, industry and researchers is that waste prevention by source reduction/waste minimization is the most desirable waste management option for toxics control.
Application of Product Life-Cycle Assessment to Product Stewardship and Pollution Prevention Programs
Authors: Fava J. A. , Page A.
Published: May 2018

The concept of product life-cycle assessment is described and its application to pollution prevention and product stewardship programs is discussed.
Activated Sludge Treatment of Petroleum Refinery Wastewater: Part 1 – Experimental Behaviour
Authors: Baker A. , Dold P.
Published: May 2018

An experimental programme was conducted to provide an initial database for development of a dynamic simulation model for activated sludge systems treating petroleum refinery wastewater. A laboratory scale single reactor aerobic activated sludge system was first operated under constant loading conditions, receiving a feed of petroleum refinery wastewater of fixed COD concentration at a constant flow rate. The steady state system was operated at sludge ages of 10 and 20 days. Data on dynamic response behaviour were obtained by operating the system under a 24 hour cyclic square-wave loading pattern; the system received the same daily influent volume of fixed COD concentration at a constant rate, but over a 12 hour period with no feed over the remainder of the 24 hour cycle. The system was monitored intensively over 24 hour cycles when operated at sludge ages of 5 and 20 days. Batch tests were conducted off-line to establish the decay rate of microorganisms and the potential for volatilization of organics from the raw wastewater. All experimentation was conducted at 20°C.
Physicochemical and Biological Treatability Studies on Surfactant Wastewaters
Authors: Çeçen F.
Published: May 2018

Laboratory-scale physicochemical and biological treatability studies were performed on wastewaters discharged from an industry producing household and heavy-duty detergents of powder and liquid type. The characterization of effluents led to the conclusion that the industry was highly pollutant in terms of BOD5, COD, surfactant, phosphorus, oil-grease, suspended solids and pH. By the use of lime in the precipitation stage about 80 % of COD and more than 90 % of phosphorus and anionic surface active agents could be removed. Following the treatment with lime the biodegradation of these wastewaters was investigated in continuously fed activated sludge units. The biokinetic constants of the reaction were determined as k = 0.76 d−1, Ks = 972 mg/l COD, a = 0.58 mg O2/mg COD, b = 0.044 mg O2/mg MLVSS.d. The experimental findings were used in the design of a full-scale treatment system.
Stability of Phosphorus Removal and Population of Bio-P-Bacteria under Short Term Disturbances in Sequencing Batch Reactor Activated Sludge Process
Authors: Okada M. , Lin C. K. , Katayama Y. , Murakami A.
Published: May 2018

Laboratory-scale sequencing batch reactor(SBR) activated sludge processes were operated to investigate the stability of phosphorus removal capacity and population of bio-P-bacteria under short term disturbances (2 to 5 days) and to characterize the structure and dynamics of bacterial population of activated sludge for phosphorus removal. The performance on phosphorus removal deteriorated in 3 days, whereas it took more than 1 week for the recovery and the time for the recovery prolonged with the length of disturbances. The responses of phosphorus removal activity and quinone profiles suggested that the deterioration and the slow recovery were dependent not on the decrease in the activity of each bio-P-bacteria but on the decrease in their population, i.e. species succession of bacteria. The isolated strains of Acinetobacter and Pseudomonas were seen to be predominant species in the total bacterial population in the activated sludge. These strains showed high activity of phosphorus removal and low specific growth rate indicating also the slow recovery.
Population Dynamics of Attached Biofilm in Anaerobic Fluidized Bed Pilot Plant
Authors: Cheng S. S. , Huang S. Y. , Lay J. J. , Tsai P. S. , Cho L. T.
Published: May 2018

An innovative anaerobic fluidized bed (AFB) with extreme height (21 metres) was designed by the UCL engineers. Food processing wastewater with relatively low COD concentration less than 1,000 ppm was treated. During the start-up period of seven months, the applied organic loadings (2 to 16 kgCOD/m3 − day) were increased stepwise with decreasing the HRT from 24 to 1.5 hours. Certain upflow velocities of 25 and 37 metres/hour were maintained to fluidize the ceramic particles up to 10 metres high. Population dynamics of the biofilm attached on particle medium was investigated in terms of increasing organic loading, cumulation of volatile fatty acids, SEM microscopic morphology and biogas production rate of BMP batch tests. About 0.09 kgVSS/kg – medium of biofilm contributed to more than half amount of biomass while the suspended sludge was susceptible to hydraulic washing-out. Filamentous network and thrix-like anaerobic bacteria were grown initially in the deep holes or crevices of the medium. After this initial biofilm network formation, certain types of short rods and small cocci were embedded in the biofilm. High organic loading and high VTA concentration provided rapid growth of discrete rods which were washed out of the fluidized bed. Appropriate upflow velocity, HRT and organic loading were essential to this process stability.
Biofilm Performance of a Fluidized Bed Biofilm Reactor for Drinking Water Denitrification
Authors: Lazarova V. Z. , Capdeville B. , Nikolov L.
Published: May 2018

The properties of two biofilms generated with different predominant organisms were studied in a laboratory-scale fluidized bed bioreactor. Bed expansion, biofilm thickness, biofilm density, protein and polysaccharide concentrations were measured and compared. A high polysaccharide concentration was observed in the less dense and more fragile biofilm of Ps. aeruginosa. The more active biofilm of Ps. stutzeri was characterized by higher protein concentration and density. The results demonstrated that the biofilm performance mostly depended on the physiological characteristics of the preponderant organism. Complete nitrate reduction was reached in both biofilms at very low biofilm thickness. Elevated residual nitrite was observed only in the biofilm of Ps. aeruginosa.
Shear Loss Characteristics of an Aerobic Biofilm
Authors: Rao Bhamidimarri S. M. , See T. T.
Published: May 2018

Growth and shear loss characteristics of phenol utilizing biofilm were studied in a concentric cylinder bioreactor. The net accumulation of the biofilm and the substrate utilisation were measured as a function of torque. Uniform biofilms were obtained up to a thickness of around 300 microns, beyond which the surface growth was non-uniform. The substrate utilisation rate, however, reached a constant value beyond film thickness of 50 to 100 microns depending on the operational torque. The maximum phenol removal rate was achieved at a shear stress of 3.5 Nm-2. The effect of shear stress on net growth rate was found to be described byand a zero net growth was obtained at a shear stress of 18.7 Nm-2.
Attachment and Growth of Biomass on Surface-Modified Activated Carbon Fibers
Authors: Kutics K. , Suzuki M.
Published: May 2018

Activated carbon fiber (ACF) was used as a model of commercial activated carbons to examine the effect of surface chemistry on the attachment behavior of bacterial biomass. Surface acidity was found to enhance the biomass-ACF interaction. When ACFs were applied as biomass support media in a continuous stirred tank reactor, surface acidity of the carbon resulted in faster biomass growth in the start-up phase. The start-up phase was simulated by a simple biomass attachment kinetics model. Experimental and calculated data show a reasonable agreement, with the exception of the hydrogenated specimen, which was interpreted by assuming that the hydrogen-reduced surface is highly reactive and then may undergo oxidation in the initial phase of operation so that the adsorption characteristics are altered.
Analyses of Rate Data for Biofilm Studies
Authors: Holder G. A.
Published: May 2018

Data for the biodegradation of glucose and sodium benzoate in aerobic biofilms are analysed using different procedures. It was found that plots of the percentage substrate removal versus some measure of the applied substrate loading gave no insight into the processes which were occurring. In contrast, plots of mean mass flux versus some measure of the applied substrate loading were much more revealing. The results demonstrate why these plots are especially appropriate for studies of mixed substrates. The results of the studies also illustrate why quantities derived by computer matching procedures should be regarded with caution. The biodegradation of both glucose and benzoate followed zero-order kinetics. Internally consistent values were derived for the zero order rate constants using different independently prepared acclimatised bioslimes. However, intercomparisons with corresponding values from well regarded literature studies revealed differences of more than an order of magnitude between different authors. The increasing emphasis on the application of computational procedures to design indicates that efforts to produce greater consistency in the tabulated values for substrate removal rates would be a worthwhile research priority. Studies of the effect of shear on biofilm packing structures coupled with removal rate measurements, and measurements of true aerobic depth may be worthwhile.
The Use of Submerged Structured Packings in Biofilm Reactors for Wastewater Treatment
Authors: Ryhiner G. , Birou B. , Gros H.
Published: May 2018

Structured packings are utilized as biomass carriers in new types of biofilm reactors. These systems have been tested and characterized for a wide range of applications, e.g. carbonaceous and nitrogenous pollution removal of domestic wastewater, purification of industrial effluents, etc. Their efficiency is discussed in terms of eliminated loads and suspended solids retention, as well as with respect to the factors influencing the costs of operation: head loss, backwash frequency, sludge water production. Design considerations of full scale units include both process-related parameters and technological aspects.
Biological Mechanisms of H2S Formation in Sewer Pipes
Authors: Attal A. , Brigodiot M. , Camacho P. , Manem J.
Published: May 2018

The purpose of this study is to gain a better understanding of the biological phenomena involved in the production of hydrogen sulfide in urban wastewater (UWW) systems.

It is found that the UWW itself naturally possesses the biomass needed to consume the sulfates. These heterotrophic sulfate-reducing bacteria populations, though immediately active in strict anaerobic conditions, are present only in very low concentrations in the UWW. A concentration of them was studied within the pressure pipes, in the form of deposits, and this justifies the high concentrations of sulfides measured in certain wastewater networks.

There are two reasons why the ferrous sulfate used as a treatment in any wastewater networks should not cause the production of additional sulfides. Firstly, the sulfate consumption kinetics are always too slow, relative to the residence time of the water in the pipe, for all of the sulfates to be consumed anyway. Secondly, the amount of assimilable carbon, soluble carbon, and carbon from suspended solid (SS) hydrolysis is insufficient.
Dimensioning of Final Settling Tanks of Large Activated Sludge Plants for High Quality Effluent
Authors: Billmeier E.
Published: May 2018

The activated sludge tank and the final settling tank represent one operating unit in which the mixed liquor suspended solids indicate the main parameter. This parameter depends on the efficiency of the final settling tank so that this building determines the capacity of the whole wastewater treatment plant. The effluent quality improves with the separation capability of the clarifier because the suspended solids contain relatively large concentrations of BOD5 and COD and significant values of organic nitrogen and total phosphorus.
Decentralisation of the Emscher Sewerage System - Planning of the Bottrop Biological Sewage Treatment Plant
Authors: Teichgräber B.
Published: May 2018

The Emschergenossenschaft plans to improve the Emscher drainage system by separating sewage and clean water. 6 or 7 subcatchment areas will be created and served by separate wastewater treatment plants. The Bottrop WWTP has been planned for 1.3 million population equivalents. It is scheduled to start operation in 1995 and its costs are estimated as totalling 820 million DM in total. Biological treatment will be effected by a low-loaded, single-stage activated sludge system with cascade denitrification and modified UCT process.
High Rate Air Activated Sludge Operation at the City of Los Angeles Hyperion Wastewater Treatment Plant
Authors: Shao Y. J. , Crosse J. , Keller E. , Jenkins D.
Published: May 2018

The City of Los Angeles USA Hyperion Treatment Plant (HTP) implemented high rate air activated sludge operations in November 1989. Using this process, the secondary treatment organic loading (F/M) was increased from 0.5 to 1.0 kg BOD/kg MLVSS/day and the MCRT reduced from 3.1 days to 1.5 days, thereby enabling the secondary treated flow to be increased from 150 mgd to 200mgd (6.6 to 8.8 m3/s).

Excellent secondary effluent quality (BOD5 = 15 mg/l, carbonaceous BOD5 = 6 mg/l, SS = 6 mg/l) is currently obtained using rectangular secondary clarifiers operated at surface overflow rates of 1,100 gal/day/ft2 (43 m3/m2/day) and low MLSS concentrations (950 mg/l). The enhanced biological phosphorus removal that was obtained when operating at a 3 day MCRT was eliminated in the change to high rate operation and struvite (MgNH4PO4(c)) build-up in the anaerobic digesters has been eliminated. Nocardia scum formation, with its odor generating potential and other associated operating problems, has also been eliminated by high rate operation.
Some Observations on Nitrification and Denitrification Following Full-Scale Trials at Henriksdal and Bromma Sewage Treatment Plants in Stockholm
Authors: Tendaj M. , Reinius L.-G. , Hultgren J.
Published: May 2018

The requirements for phosphorus and nitrogen removal will be more stringent for the sewage treatment plants in Stockholm in the future. A lot of work has been done during the last 5-6 years to learn in what way the three sewage treatment plants ought to be extended to meet those more stringent requirements. The paper presents some experience from this work and gives a brief description of the final solution for the two largest plants, Henriksdal and Bromma.
Operational Results of Waste Water Treatment Plants with Biological N and N Elimination
Authors: Schlegel S.
Published: May 2018

To an ever-increasing degree, it is nowadays demanded of treatment plants that they eliminate nitrogen and phosphorus from the waste water. Of the 81 treatment plants operated by the Lippeverband, a large number even now eliminate nitrogen although the percentage eliminated is still not optimal since, until recently, N elimination was still predominantly considered from the point of view of economy and stabilization of the degradation process. A further increase is definitely possible by means of an improved process and control technology. Phosphorus elimination can also be largely effected biologically. One of the plants provided with denitrification stages was appropriately retrofitted for this process. The results after two years of operation show that an optimum treatment efficiency can be achieved with a plant of this type.
Study of the Factors Affecting Activated Sludge Settling in Domestic Wastewater Treatment Plants
Authors: Echeverría E. , Seco A. , Ferrer J.
Published: May 2018

A study has been made of the influence of the process parameters on the settling characteristics of sludge in domestic wastewater treatment plants. The experiments were conducted at a pilot plant situated at the Wastewater Treatment Plant of Valencia, Spain (1,000,000 inhabitants). The influent to the pilot plant was the same as that of the plant.

It was found that F/M ratios in the range of 0.25-0.60 g DBO5/g MLVSS day produce values of SVI representative of good settleability of the sludge. Values of sulphide concentration in the influent above 1.0 mg/l negatively affect the process, causing bulking and floating sludge. High values of fats were found to have no influence on the SVI, but did affect the performance of depuration. At low DO levels, the appearance of bulking with high SVI values was observed. Throughout the experiments, the permanence of nutrients (basically N and P) above that required for the growth of the microorganisms was proved.
Minimising Nuisances by Covering Compact Sewage Treatment Plants
Authors: Rogalla F. , Roudon G. , Sibony J. , Blondeau F.
Published: May 2018

Stringent effluent quality programs to limit wastewater discharges into receiving waters require extensive upgrading of conventional wastewater treatment plants. Large facilities built some decades ago are now often located in densely urbanised areas where land is unavailable. Since nitrogen and phophorus removal often require additional unit processes, innovative solutions have to be found to upgrade existing plants for nutrient removal. This paper shows large scale examples of compact technology and the additional upgrading flexibility provided.

New facilities are implemented in sensitive neighborhoods by creative siting under sports stadiums, parks or buildings. In covered plants, air emission control becomes of primary importance. To reduce visual impacts and facilitate odour control, more and more underground treatment plants are constructed, allowing multiple use of plant surfaces. Several plants are illustrated in inner-city locations, avoiding infrastructure cost to pump sewage to remote sites.

Most of the presented plants incorporate spacesaving settling facilities and high rate biological reactors to reduce the ‘footprints' of the installations and thus favour coverage. Parallel plates in primary setllers reduce the surface to about one tenth of conventional systems. Biocarbone aerated filters combine biodegradation with very high removal rates and retention of particles in one reactor, without additional clarification or filtration. Air treatment for large plant is mostly performed by chemical scrubbing, completely eliminating environmental nuisances. Performance results of both air and water treatment technology are given.

Examples include recent sewage treatment plants on the French Mediterranean Coast. A physico-chemical treatment plant for 1 Million p.e. has operated since 1987 under a stadium in Marseille. In Monaco, the sewage treatment plant for 100 000 p.e.is located in the city center underneath a building of 3000 m2. Primary lamella settlers are followed by biological treatment on Biocarbone aerated filters and air is chemically deodourised. Similar technology is used in Antibes' 200 000 p.e. plant, integrated underneath a park close to the beach.
Relationships between Population Dynamics and Operating Parameters in an Activated Sludge-Plant by Statistical Analysis
Authors: Cingolani L. , Cossignani M. , Miliani R.
Published: May 2018

Statistical analyses were applied to data from a series of 38 samples collected in an aerobic treatment plant from November 1989 to December 1990. Relationships between microfauna structure and plant operating conditions were found. Amount and quality of microfauna groups and species found in activated sludge proved useful to suggest the possible causes of disfunctions.
Experience with Two-Stage Activated Sludge Plants for Industrial Wastewaters in Korea
Authors: Schulze-Rettmer R. , Kim S. S. , Son S. S.
Published: May 2018

The two-stage activated sludge process (AB-process, i.e. adsorption activated sludge process) invented by Boehnke was successfully applied to several municipal and industrial wastewaters in Korea. The first large wastewater treatment plant for the combined effluents of 22 textile dyeing companies was constructed in Taegu and started operation in 1989. Two years earlier pilot plant runs were performed. The AB-process proved to be superior to any other activated sludge process. BOD was reduced from 1200 mg/l down to 24 mg/l. In the meantime in Korea several further AB-process treatment plants were constructed, the overall planning and constructing period being not longer than one year.
Heavy Metals in Wastewater Treatment Plant Sludges in the Czech Republic
Authors: Sedláček M. , Just T.
Published: May 2018

Since 1987 operators of municipal wastewater treatment plants, having the population equivalent over 5 000, monitor systematically heavy metals in sludges, based on one or two samplings on the average annually. Generally, Cd, Cr, Cu, Ni, Pb and Zn are monitored: since 1989 Hg is becoming the centre of systematic attention. Occasional data are available on concentrated Ag, Co, As and Mo. These data were collected and ordered by the authors of the paper. On their basis lines of exceedance were plotted and sets were prepared, characterizing both localities with the common level of the sludge contamination, and with the extremely low contamination level reflecting the condition that could be achieved if measures limiting the heavy metal input into public sewerage systems were adopted.

The results achieved were compared with heavy metal concentration limits, as determined in the Industrial composts standard, both for raw materials used for the compost production, and for composts of Ist and IInd grades. With a view to the general environmental contamination, and considering the present economic and agricultural use, the input raw materials should meet the demands that are required under the standard for the prepared composts.
Improved Biological Phosphorus Removal Resulting from the Enrichment of Reactor Feed with Fermentation Products
Authors: Lötter L. H. , Pitman A. R.
Published: May 2018

Research in South Africa has highlighted the dependence of biological phosphate removal mechanisms on the presence of certain minimum concentrations of some readily biodegradable materials including interalia volatile fatty acids. Successful generation of these compounds has been achieved at recently commissioned facilities at three of Johannesburg' activated sludge plants. Elutriation of the volatile fatty acids from the sludge was achieved by recycling sludge to the influent sewage stream. Significant improvements in phosphate removal were observed, thus reducing the demand for chemical dosing to achieve the phosphate standard.

In this paper the effect of altering the feed sewage characteristics on biological phosphorus removal is discussed.
The Selection and Design of Sequencing Batch Reactors for Treatment Capacity Expansion in Abu Dhabi
Authors: Ellis T. G. , Soulsby M. R. , Harper P. C.
Published: May 2018

Innovative planning and design were key elements in the selection of sequencing batch reactors to provide 40% capacity expansion for the existing wastewater treatment works in Abu Dhabi. The nitrification/denitrification mode of SBR operation was selected to provide secondary treatment prior to tertiary filtration and full effluent reuse for irrigation.
Achievement of Biological Nutrient Removal in Full-Scale Rotating Biological Contactor Watsewater Treatment Plant
Authors: Neu K. E.
Published: May 2018

A Central Wisconsin municipal treatment plant (WWTP) with a significant industrial contribution and seven (7) years of Rotating Biological Contactor (RBC) operation was the demonstration site for process modifications which provided significant biological nutrient removal (BNR). The study was conducted June-October, 1990. The plant was near 70% of hydraulic design load and averaged 90% of organic design load, with numerous excursions above organic design load. The BOD:P ratio was above 20:1, and the BOD:TKN ratio was above 10:1. Process modifications resulted in total phosphorus and total nitrogen reductions of 60-90% without chemical addition. Other benefits realized include increased clarity of the secondary effluent and an approximate 50% reduction of RBC shaft biomass weight.
Effect of Dissolved Oxygen on Phenols Breakthrough from GAC Adsorbers
Authors: Vidic R. D. , Suidan M. T.
Published: May 2018

This study demonstrates that molecular oxygen plays an important role in the adsorption of organic compounds from water by activated carbon. It was determined that the adsorptive capacity of granular activated carbon (GAC) for o-cresol can increase by almost 200% as a result of the presence of molecular oxygen in the test environment (oxic conditions). This increase in adsorptive capacity is not due to biological activity but can be totally attributed to the polymerization of o-cresol on the carbon surface under oxic conditions. The rate of adsorbate polymerization is such that the presence of molecular oxygen does not influence adsorption kinetics during the first 12 hours of adsorbent-adsorbate contact. However, the concentration of dissolved oxygen in the feed to a GAC adsorber can significantly influence the breakthrough of adsorbate. As the concentration of dissolved oxygen increased, more of this increased capacity is utilized during the early phase of breakthrough and, consequently, initial breakthrough is delayed. This phenomenon might completely change the existing procedures for the design and operation of GAC adsorbers in that it provides a competitive edge for adsorption as a treatment technology in water purification.
Separation of Hydrophobic Organic Compounds from Wastewater Using Surfactant Aggregates on Alumina Particles
Authors: Valsaraj K. T.
Published: May 2018

The adsorption of several hydrophobic organic compounds (HOCs) from water on alumina surfaces modified by the presence of surfactant “hemi-micelles” is discussed. The solubilisation of HOCs in hemi-micelles provides a convenient way of concentrating them on a solid substrate that can be subsequently regenerated with a minimum effort such as a change of pH since the formation and dissipation of hemi-micelles is a function of pH. Adsorption studies showed that the partition constants of HOCs with hemi-micelles of an anionic surfactant (sodium dodecylsulfate) on alumina can be predicted from a knowledge of their octanol-water partition constants.
Design Procedure for Side Weir in Triangular Channel
Authors: Uyumaz A.
Published: May 2018

Side weirs have been used extensively for water-level control in irrigation and drainage canal systems, as a means of diverting excess water into relief channels for flood protection works, and as storm overflows from urban sewage systems. In this study, flow over side weir in triangular channel is reported. Theoretical model is obtained from energy principles and is solved by a finite difference method. The results are presented in diagrammatic form for practical use. The study covers both sub-and supercritical flow regimes. Derived expressions for the water surface profiles for these regimes are compared with experimental results.
Innovative Computing Techniques for Development of an Integrated Computer Control System
Authors: Patry G. G. , Barnett M. W.
Published: May 2018

Over the past decade there has been a shift in emphasis from design and construction of wastewater treatment facilities to operation. Poor plant performance, high costs and damage to the environment have resulted from operational problems. Wastewater treatment consists of a complex sequence of inter-dependent biological, physical and chemical processes subject to time-varying hydraulic and organic load conditions. Wastewater treatment process operation and control is a knowledge intensive task. Research on improving operation and control has centred on identifying important mechanisms responsible for observed behaviour and modelling both the process and optimum ways of operating the process. These models have served as useful tools for improving operation and control. Many different approaches have been used, including deterministic modelling, stochastic modelling and, more recently, linguistic modelling. Complex mathematical models of wastewater treatment processes consisting of large numbers of non-linear differential equations can be constructed using tools such as the General Purpose Simulator (GPS) and, given appropriate data, model parameters can be evaluated and updated using existing optimization routines. Object oriented programming (OOP) and a model based reasoning (MBR) approach provides a useful framework for development of deep-knowledge expert systems (ES). Data-driven modelling methods, including both time series analysis and artificial neural network (ANN) techniques, can also be employed to make maximum use of information contained in process data. Each of these model types is a necessary component of a computer system for operational control of wastewater treatment but, in isolation, none are sufficient for making the system robust. An integrated environment for combining these techniques has been developed for this purpose and the basis for its development is described.
Application of Linked Personal Computers for Automatic Control in Large Sewage Works
Authors: Bongards M. , Braun J. , Feyen H. A.
Published: May 2018

So far only very large sewage treatment plants (STP) are equipped with real process computers. High investment costs and complicated handling prevented their application in medium-sized and smaller STPs. Meanwhile Personal Computers became so efficient and reliable that they can be used for automatic control of industrial processes.

In this paper the successful enlargement of the central STP of Stolberg-Steinfurt for 120,000 inhabitant equivalents is described. In the central facility seven linked personal computers co-operate in a local area network (LAN) for monitoring and optimization of different processes. They are connected with seven programmable controllers in outstations on site. The data transfer between the central control room and the outstations takes place using RS 232 C interfaces. Because of the use of common office computers in combination with industrially proved controllers the operators very soon accepted the system. After one year of operating experience they assess the system as a valuable tool.
Determining Drainage Pattern Using DEM Data for Nonpoint-Source Water Quality Modeling
Authors: Kao J.-J.
Published: May 2018

The drainage pattern of a watershed is an important parameter in nonpoint-source water quality modeling. Manual preparation of this pattern from topographic maps is time–consuming and sometimes subjective. Digital Elevation Model (DEM) data are fundamental cartographic data stored in a uniform grid system which can be easily processed by the computer. Using DEM data and a set of pre-defined rules, the drainage pattern can be automatically determined. Six grid-based methods have been developed, and three of them have been tested for a case study, an area enclosing a subwatershed of Chin-Mei River, Taipei County, Taiwan, R. O. C. The results are comparable to the manually prepared drainage pattern, although several complexities exist for areas such as depression and highly irregular areas. Several refined rules based on the drainage patterns in adjacent areas are utilized to modify the drainage patterns in these areas. Compared with the conventional manual method, the proposed automated methods are much more efficient for regional water quality studies.