bluuebunny/crossref_metadata_2025 huggingface dataset:
Application of a GIS-Based Nonpoint Source Nutrient Loading Model for Assessment of Land Development Scenarios and Water Quality in Owasco Lake, New York
Authors: Heidtke T. M. , Auer M. T.
Published: May 2018

The magnitude and water quality implications of nonpoint source phosphorus loadings to Owasco Lake (New York) are evaluated through the application of a methodology which links geographic characteristics, longterm average runoff loads and a set of critical lakewide water quality response parameters. The approach utilizes the Universal Soil Loss Equation together with empirical loading functions to derive representative phosphorus export coefficients for the local drainage system. Cumulative loadings from individual sub-basins within the watershed serve as input to a simple water quality model of Owasco Lake, showing the expected lake response in terms of average total phosphorus concentration, trophic state, water transparency, and minimum hypolimnetic dissolved oxygen concentration. The methodology facilitates easy and rapid assessment of general watershed management and development scenarios of interest A unique aspect of the approach is its dependence upon descriptive data supplied by a Geographic Information System (GIS) to establish the coincidence of specific land use, soil texture and surface slope attributes within each of the hydrologie sub-basins comprising the overall watershed. The GIS-generated attribute matrices provide a much more accurate depiction of critical geographic characteristics known to impact nonpoint source runoff loadings, thereby improving the reliability of current and projected phosphorus loads to Owasco Lake.
Movement of Nitrogen through an Agricultural Riparian Zone: 1. Field Studies
Authors: Clausen J. C. , Wayland K. G. , Saldi K. A. , Guillard K.
Published: May 2018

Forested riparian areas are believed to be important for reducing nonpoint source pollutants. These areas along streams, lakes, and wetlands have been reported to trap sediment and nutrients and enhance denitrification. Past research on the effectiveness of riparian areas has been based on existing forests rather than restored areas. An experiment using the paired-watershed design was established in northeastern Connecticut during 1992 to determine the water quality effects of reforestation on a riparian zone currently cropped in maize. Water quality fluxes in precipitation, overland flow, soil solution, groundwater, and streamflow were determined. Results indicate that this 35 m wide riparian zone had little attenuating influence on N concentrations in groundwater based on NO3−N concentrations and NO3−N:C1 ratios. The primary N flux to the stream was in the groundwater. Denitrification did not appear to be a major process operating in this system. Reforestation of this riparian buffer should result in improved surface and groundwater quality.
The Application of Creams Model to Forecasting the Nitrate and Chloride Leaching from Grassland
Authors: Sapek B. , Sapek A.
Published: May 2018

Pollution of groundwater due to nitrate is a serious problem in Poland. A significant part of this pollution originates from permanent grassland. The experimental results from four experiments conducted near Warsaw were compared and supplemented with the simulation made by means of the CREAMS model. A good agreement was found between the experimental and the simulated balance of nitrogen as well as chloride. The estimated nitrate nitrogen concentration in percolated water was between 10 and 90 mg N/l, which presents a real danger to the quality of groundwater. The obtained results ascertained that the CREAMS model is a proper tool for forecasting the nitrogen balance on permanent grassland, particularly the losses of nitrogen due to nitrate leaching. The chloride used as an experimental and/or calculated tracer to the nitrogen balance was shown to be advantageously valuable.
Reduction of Combined Sewer Overflow Quality by Application of the Coagulation Process
Authors: Weyand Michael , Dohmann Max , Fries Dirk , Ilchmann Harald
Published: May 2018

In order to store the bulk of storm water runnoff German combined sewer systems are equipped with detention facilities. In spite of this fact, combined sewer overflow discharge contributes a considerable part to the existing river pollution. Reducing the amount of the discharged pollution load is the objective of a research project. At a large pilot plant investigations are ongoing into the effect of the coagulation process being applied at combined sewer detention tanks. In several experimental phases the influence of different variation parameters upon its efficiency is tested. First results show the general benefit of the coagulation process removing COD and total phosphorus. The attainable reduction effect depends on the constructive and hydraulic conditions within the detention tank to a high degree. Considering the now available results, it is expected that the application of the coagulation process within combined sewer detention tanks will be profitable when high standards for the quality of receiving waters are claimed.
Extension of the Sewage Treatment Plants in Stockholm: Some Technical and Economical Aspects
Authors: Hultgren J. , Reinius L. G.
Published: May 2018

The requirements for the sewage treatment plants in Sweden will be more stringent in the future. The three plants in Stockholm, Henriksdal, Bromma and Loudden have to be extended to meet requirements for nitrogen removal and increased phosphorus removal. Since 1989 the plants have the same recipient for the treated sewage and to save money during the future extension the city would like to regard the three effluents as one common. The authorities have not yet decided to admit this but there is a good chance for it. The paper describes the strategy for extension and how the plants have been designed.
Combined Aerated Ponds and Chemical Clarification in the Treatment of Petrochemical Wastewater
Authors: Galil N. , Rebhun M.
Published: May 2018

Biotreatment of wastewater from an integrated oil refinery by activated sludge and by RBC was studied and reported by the authors in previous publications. The objective of this study is to develop a low cost process combination by utilizing facilities, which exist in most industries, as treatment means as well as recipient for the renovated effluent. The idea is to share the task of the bioprocess between: a) a partial primary stage biotreatment by two aeration ponds (AP); b) chemical clarification of the primary stage effluent for removal of MLSS and colloids synthesized in the first process, by utilizing the existing lime clarification-softening system; c) completion of the bioprocess by a recircuiated cooling system (RCS) which has a high bio-oxidation capacity and also reuses the clarified effluent as make-up. The paper analyzes experimental data obtained from a pilot plant including two aerated tanks in series with a total hydraulic residence time of 2 days, followed by a lime clarifier. The main characteristic of the AP process is that hydraulic and sludge residence times are identical; two days are considered as very short SRT, especially in petrochemical wastewater, while in activated sludge SRT is usually above 15 days. The AP removed 60% of the COD - 15% by stripping - and 80% of the BOD; the oil removal was up to 50%. The chemical lime clarification improved the AP effluent reduction; suspended solids from 160 to 8 mg/l; oil from 34 to 9 mg/l; total COD from 290 to 170 mg/l. The study includes data on volumes and characteristics of the chemical sludge produced. The organic matter residual from previous treatment stages, most of it in soluble form, will be biodegraded in the RCS. The characteristics of RCS working as biological reactor were studied by Rebhun et al. and reported elsewhere. This study emphasizes economy in capital investment and beneficial reuse of industrial wastewater. The combined system includes two biological barries, AP and RCS, combined with the chemical clarification barrier, providing a reliable and low cost process combination.
Biological Treatment of a High Salinity Chemical Industrial Wastewater
Authors: Belkin Shimshon , Brenner Asher , Abeliovich Aharon
Published: May 2018

Various laboratory-scale process configurations were tested for the biological treatment of a combined wastewater stream of several chemical factories. The untreated wastewaters, rich in halogenated organics (1250±389 mg/l DOC), were also highly saline (32±11 g/liter TDS 550°C) and toxic (Microtox™ EC50 = 1.5±2.0%). Biphasic (anaerobic/aerobic) laboratory bench-scale reactor systems yielded reduction of dissolved organic carbon by 70 to 84%, in the absence and presence of powdered activated carbon, respectively. The anaerobic phase proved to be essential in all systems, both for dissolved organic carbon removal and for detoxification. Similar efficiencies were obtained in either activated sludge or aerated lagoon type reactors, but in the latter case, longer hydraulic retention times were required. DOC removal was found to decrease with increased salt concentration; however, a 50% efficiency was achieved even at 90 g/l TDS. Toxicity elimination as judged by the Microtox™ assay was highly variable in the absence of activated carbon but stable and efficient in its presence.
Fast Assessment of Toxicants Adsorption on Activated Carbon Using a Luminous Bacteria Bioassay
Authors: Brenner Asher , Belkin Shimshon , Ulitzur Shimon , Abeliovich Aharon
Published: May 2018

A new approach for the evaluation of activated carbon adsorption characteristics in the treatment of water contaminated by toxic organic compounds is presented. It is based on direct determination of the toxicity in the treated water, as opposed to actual chemical analysis of their constituents. The MicrotoxR bioassay, based upon measurement of bacterial bioluminescence, was utilized for this purpose. The suitability of this approach was judged by applying values of residual toxicities, obtained during batch adsorption experiments with mixtures of pure chemicals and industrial wastes, to traditional mathematical models. The Freundlich model was found to describe accurately adsorption isotherms derived from balances of residual toxicities, as well as from residual concentrations of specific chemicals. This approach allows a fast, convenient assessment of selective toxicant adsorption, alleviating the need for complex analytical methods.
Activated Carbon for Air Purification in New York City's Sewage Treatment Plants
Authors: Turk Amos , Mahmood Khizar , Mozaffari Jahangir
Published: May 2018

Odors from New York City's sewage treatment plants are controlled by activated carbon housed in 44 large towers, each holding about 11 tons of carbon. The carbons are impregnated with NaOH or with KOH, or are unimpregnated but continuously injected with ammonia gas.

A study is now under way in our laboratory to monitor the progressive exhaustion of these carbon beds and to predict their useful lifetimes. The monitoring tests include a measure of the residual breakthrough capacity of the carbon for hydrogen sulfide, and an estimate of the remaining capacity for physical adsorption of other gases. For the caustic-impregnated carbons, the tests include a measure of the actual life-extension that can be realized by the retrofit of ammonia injection without interrupting the operation of the carbon vessels. A procedure to predict the results of in situ regeneration is described.
Viruses and Water: Problems, Detection, and Control
Authors: Dizer H. , Dürkop J. , Grohmann A. , Kopecka H. , López-Pila J. M.
Published: May 2018

Secondary effluent of wastewater treatment plants contains a high number of viruses and other pathogens, which pose a health risk to the population, (especially when receiv ng waters are used for bathing and swimming, or for growing shellfish. In areas with a high density of population, where drinking water supply is dependent on surface waters and contaminated rivers are the primary source of drinking water, failure of the filtration or of the disinfection step, or of any other “barriers” supposed to warrant safe potable water, will increase the risk of health hazard for the consumer.

We have compared the efficiency of viral elimination in secondary effluent by flocculation, uv rradiation and membrane filtration taking naturally occurring, or additionally seeded f2 phages, as indicator for viruses. Flocculation decreased the number of phages present in secondary effluent by more than two logs. If combined with uv irradiation, the elimination reached five additional logs. Membrane filtration eliminated essentially all naturally occurring phages.

Improvement of the quality of surface waters calls for a refinement of detection methods for viruses. We have found that the polymerase chain reaction (PCR) might be used for detecting viruses in surface waters.
Ecological Physiology of an Assembly of Photosynthetic Microalgae in Wastewater Oxidation Ponds
Authors: Fruend Claudia , Romem Eitan , Post Anton F.
Published: May 2018

During the year 1991 an intensive study was made of parameters governing phytoplankton dominance and succession in wastewater oxidation ponds in relation to their photosynthetic properties under environmental stress. The most successful phytoplankton species was Chlorella vulgaris based on its high photosynthetic potential and its relatively modest contribution to suspended solids. It bloomed during spring after which euglenoids and cyanobacteria became increasingly important. In late summer the green alga Ankistrodesmus became increasingly dominant. This alga strongly contributed to a rise in total suspended solids and had a low photosynthetic capacity. Its dominance appeared to be linked to a relief of ammonium stress on the system following lower organic loading during summer months. A potential for primary productivity in the presence of sulfide was present throughout the year. The pattern of activity correlated with blooms of Chlorella and coccoid cyanobacteria. Two cell types of Chlorella vulgaris were observed occurring in a stable ratio throughout the year. One type is fully phototrophic and only slightly affected by presence of organic solutes like acetate. Its photosynthesis has a pronounced resistance to sulfide and ammonia stress. The second type is auxotrophic and capable of exploiting various organic carbon sources. The presence of organic carbon strongly reduces photosynthesis in this type. Both Chlorella types appeared to be highly adapted to the environmental stress imposed on photosynthetic phytoplankton in the oxidation pond inlet. This stress was defined as being derived from anoxic conditions lead to elevated concentration in volatile fatty acids (acetate, lactate etc.), ammonium and sulfide.
Proposed California Regulations for Groundwater Recharge with Reclaimed Municipal Wastewater
Authors: Asano Takashi
Published: May 2018

The proposed California regulations for groundwater recharge with reclaimed municipal wastewater are presented with the basis and rationale for key requirements. The treatment and recharge basin requirements have been developed to control the migration of pathogens, nitrogen, and trace organics in the extracted groundwater. The regulations rely on a combination of controls intended to maintain a microbiologically and chemically safe groundwater recharge operation. These regulations provide uniform statewide criteria that will promote groundwater recharge projects using reclaimed municipal wastewater.
New Method for Estimation of Contaminant Travel Rate in Unsaturated Zone under Irrigated Soils
Authors: Zilberbrand M.
Published: May 2018

In a thick unsaturated zone, when quick deep penetration of rain and irrigation water is absent, at the depths below 3-5 m there exists a zone of downwards quasi-steady water flow. Darcy's water velocity in this zone remains constant with depth and equal to the groundwater recharge rate; unit hydraulic head gradient occurs above the capillary fringe. Therefore, contaminant travel rate is equal to the ratio of hydraulic conductivity (K) and effective volumetric water content (θef). Field tracer experiments and laboratory K and θef determinations were carried out for several representative irrigated lots in the South Ukraine. The dependence of θef on capillary tension was studied for the first time. For loess loam with a capillary tension decreasing from 46 kPa to 0, θef nonlinearly increases from 12% to 27-28%. The effective water content portion (β1) of the total water content increases nonlinearly from 0.38 to 0.65-0.7. The β1 values were estimated for different unsaturated sedimentary rocks. For a capillary tension of about 5 kPa β1 values were: 0.88-0.99 for sands, about 0.65 for loess loam and chestnut soil, about 0.6 for sandy loam, about 0.32 for limestone and about 0.07 for clay. Calculated chloride travel rates in loess loams under irrigated soils fit the values of 0.001-0.003 m/day, determined by the results of field tracer experiments.
Esr Indication of Heavy Metal Contamination of Urban Atmosphere
Authors: Iosefzon-Kuyavskaya B. , Myrlyan N. , Shames A.
Published: May 2018

Electron Spin Resonance (ESR) was used for the examination oi dust samples collected from snow in an urban area. On the main doublet ESR line attributed to the signal of paramagnetic metals, a singlet line characteristic for stable free radical centers (FRC) was observed. A negative correlation of significant level between FRC signal intensity and heavy metal (HM) content was established. It was shown that FRC line intensity of dust may be used as a surrogate parameter for the estimation of air pollution by HM.
Organic and Trace Metal Pollution in the Sediments of the Kishon River (Israel) and Possible Influence on the Marine Environment
Authors: Cohen Y. , Kress N. , Hornung H.
Published: May 2018

The sediments of the lower reach of the Kishon river, its harbors and estuary, sampled in 1989-1991, were highly polluted by trace metals and petroleum derived compounds released by the adjacent industries. The contamination was highest in the sediment deposition area of the Kishon fishing harbor and decreased seaward. River-borne pollution was also evident in Haifa Bay opposite the Kishon estuary. Contaminants trapped in the sediments of the lower Kishon river system can reach the marine environment through bottom transport of sediment particles and also as a result of disposal at sea of dredge spoils from the river channel and harbors. On the basis of the findings of the study, it was recommended to stop the long-time practice of dumping dredge spoils from the Kishon fishing harbor into the relatively clean Haifa Bay and to use instead an offshore deep water disposal site.
The Impact of Quaternary Paleoclimatic Change on the Carnivores of Israel
Authors: Dayan T.
Published: May 2018

The Quaternary is a period of considerable climatic change. Climatic fluctuations have been subject to numerous studies based on various scientific disciplines (e.g., geology, sedimentology, palynology) that now enable us to reconstruct the paleoclimates of the last glacial period with some accuracy. In Israel such studies tell us of shifts in both ambient temperatures and in humidity. These paleoclimatic changes had paleoecological effect. Studying the paleoecology of the fauna of Israel may give us a key to understanding the effects of past climatic shifts, and to predicting the impact of future climatic change in this country.

Here I follow changes in distribution, diversity, and morphology of carnivores throughout the last glacial of Israel. Size increase and shifts in distribution occurred in some carnivore species, and overall there is a strong correlation between humidity and species diversity. Carnivores typically exhibit wide geographic distributions, and wide environmental tolerance. Therefore paleoecological effects of paleoclimatic shifts in carnivores may indicate similar effects in other, less euryecious, terrestrial mammals.
Biogenic Weathering of Marble Monuments in Didim, Turkey and in Trajan's Column, Rome
Authors: Danin Avinoam
Published: May 2018

The Temple of Apollo in Didim, Turkey, was built in 560-550 B.C. with marble. Mean annual rainfall there is 656 mm. Much of the marble surface is covered by a black crust of microorganisms. Weathering patterns, associated mainly with cyanobacteria, observed there were: 1. Exfoliation with pleurocapsalean cyanobacteria in fissures. 2. Gradual removal, by splashing rain drops, of marble crystals, the coherence of which is reduced as a result of microbial activity. 3. Pits formed by cyanobacteria living in circular patches. The mechanism described in No. 2, leads there to the creation of depressions where the lithobionts are situated. Trajan's column was erected in Rome 112 C.E. Mean annual rainfall there is ca. 700 mm. The column is almost devoid of microbial life at present, but until 1942 had many patches of microbial black crusts. From 1942 to 1948 it was covered by brick walls and sand as a way of protection against war hazards. The light-demanding microorganisms that populated the monument for hundreds of years disappeared after being covered for 6 years and have not returned yet. Pits resembling those in Didim damaged much of the artistic relief on parts of Trajan's column. The most affected parts are those facing south and southeast. These are the directions of the most common incident rainfall in Rome which bring water at high energy to the marble monument.
Modelling Sediment Transport and Sediment Quality in a Shallow Dutch Lake (Lake Ketel)
Authors: Blom G. , Toet C.
Published: May 2018

Lake Ketel is a shallow Dutch lake, part of the river Rhine delta, with a surface area of 38 km2. Between 1960 and 1980 15×106 m3 contaminated sediment accumulated in the lake. After 1980 the contaminant load started to decrease. A common hypothesis was that the relatively clean solids supplied now, would slowly cover the contaminated sediment layer. Research indicated however a serious erosion of old and polluted bottom sediments.

To quantify resuspension and sedimentation fluxes the sediment transport model STRESS-2d has been applied. Simulation results show a net sedimentation of 300×l06 kg year−1, but an erosion of old and polluted sediment of 350×106 kg year−1. In large areas in the lake net sedimentation is only a few millimetres a year, while high resuspension and sedimentation fluxes lead to an intensive interaction between sediment and water.

Spatial variability in resuspension and sedimentation fluxes will lead to spatial gradients in the response of the bottom sediment to the reduced contaminant load. Based on the simulated resuspension and sedimentation fluxes, a simple model for the Cd concentration in the bottom sediment has been developed. Simulation results show a relatively fast decrease of the Cd concentration in the upper sediment layer areas with high net sedimentation and/or (brute) resuspension and sedimentation fluxes.
Degradation of Tributyltin in Freshwater and Estuarine Marina Sediments
Authors: Dowson P. H. , Bubb J. M. , Williams T. P. , Lester J. N.
Published: May 2018

The degradation of tributyltin (TBT) in contaminated freshwater and estuarine sediments was investigated for a 330 day period under controlled laboratory conditions. Rates of TBT degradation at different depths were established using regression modelling and revealed TBT half lives ranging from 360-775 d in surficial sediments. There appeared to be little difference in degradation rates between freshwater and estuarine sediments, although a notable increase in TBT half life was evident in TBT spiked sediments. Degradation values suggest that TBT either debutylates to DBT and MBT in aerobic sediments or degrades to DBT which is subsequently desorbed to the overlying water. In anaerobic sediment the half life of TBT was not discernible and appeared to be in the order of tens of years. Biotic processes would seem to be the most important mechanisms for the decomposition of TBT in freshwater and estuarine sediments.
Laboratory Studies of the Effects of Dissolved Organic Material on the Adsorption of Organochlorine Pesticides by Sediments and Transport in Rivers
Authors: Ding J.-Y. , Wu S.-C.
Published: May 2018

In this study experiments simulating sediment/water system were carried on with sediments spiked with aldrin, heptachlor epoxide and p,p'-DDE. It was expected that these hydrophobic contaminants would be released to the overlying water column from sediment bed with molecular diffusion and co-diffusion with dissolved organic matter (DOM) as well. A three-phase-transport model including aqueous, solid and mobile adsorptive phases was developed and used to describe the behavior of these contaminants and to explain the results of the experiments. Sensitivity analyses show that observable effects of DOM occur only under conditions of high partition coefficient (Koc) of the contaminant and high rate of transfer from sediment organic matter to DOM. In this study, owing to the low concentration of DOM and relatively low hydrophobicity of the compounds, the DOM-associated pollutant flux does not significantly contribute to the total flux. Also, the simulated results of the model can reasonably explain the variations of the concentrations of the spiked compounds observed in the microcosms.
Binding and Mobilization of Heavy Metals in Contaminated Sediments Affected by pH and Redox Potential
Authors: Calmano W. , Hong J. , Förstner U.
Published: May 2018

In a contaminated sediment from Hamburg harbour, acid production, mobilization of Cu, Zn, Pb, and Cd at different redox- and pH-conditions, and the transfer and change of those particle bound metals are studied. During oxidation the pH value in the sediment suspension decreases from about 7 to 3.4 because of the low acid neutralization capacity (ANC). This leads to a mobilization of heavy metals whereby Cd and Zn as distinguished from Cu and Pb are strongly released. Also a change in particulate phase specific heavy metal binding forms is found. Generally the easily and moderately reducible fractions increase during oxidation while the sulfidic fraction decreases. Also great changes were found for the dissolved Zn-and Cd-concentrations which increased continuously. The results show that at identical pH values obviously more metals are mobilized in the oxidized sediment than in the reduced state. But although the pH value is the key factor - in particular if it sinks below 4.5 - the redox conditions may also control the mobilization of certain metals. Consequently, also in well buffered sediments a mobilization of metals during oxidation cannot be excluded.
Remediation of PCB-Contaminated Sediments in Lake Järns Jon, Emän River System, Sweden
Authors: Gullbring P. , Hammar T.
Published: May 2018

Järnsjön, a lake in the Swedish river Emån, contains approx. 400 kg of PCB which is slowly leaching out from the sediments. An analysis program has shown that the Järnsjön sediments are the primary source for ongoing discharge of PCB to the river. Based on the current yearly discharge of 7 kg PCB, the sediments will cause problems during several decades.

The Emän river is classified as a resource of national importance. Remediation of Järnsjön is necessary if continued damage is to be avoided. However, remedial activities in lake Järnsjön can lead to an additional load on Emån. Restrictions on such releases during remediation of Järnsjön will therefore be stringently applied.

The feasibility of remediating Järnsjön, has been examined in a number of studies carried out by the Swedish EPA together with different universities, institutes and consulting companies. A primary alternative has been selected. This alternative includes vacuum dredging within a protective barrier of silt screens. Dredged material will be dewatered and disposed of in a special landfill. This remedial action is estimated to cost appr. 40 million Swedish kronor. (6 - 8 million dollars). The remediation has started and will be concluded in 1994.
Sediment Quality Objectives and Criteria Development in Germany
Authors: Förstner U. , Ahlf W. , Calmano W.
Published: May 2018

New objectives regarding the improvement of water quality as well as problems with the resuspension and land deposition of dredged materials require a standardized assessment of sediment quality. Numerical approaches are based on the accumulation, pore water concentrations, solid/liquid partition and elution properties of contaminants; these non-biological schemes can be extended and completed by additional biological criteria. Specific biological approaches have been combined with chemical surveys (for example Sediment Quality Triad). In Germany, numerical criteria are based on the background approach. Biological criteria approaches include bioassays on sediment, porewater and elutriates; recent developments are directed towards microbial solid phase bioassays. Special emphasis is placed on the characteristics of the mineral and organic solid substrate, in particular, buffer capacity against pH-depression; these components should be classified on the basis of the carbonate and sulfide inventories.
Remediation Work for Mercury Contaminated Bay – Experiences of Minamata Bay Project, Japan
Authors: Hosokawa Y.
Published: May 2018

The Minamata Bay remedial project, which commenced in 1977, was completed in 1990.1.5 million m3 of mercury contaminated sediment were treated by careful dredging and confined reclamation. A contaminated area of 2 million m2 in Minimata Bay was decontaminated.

During this large project, we have faced several technical problems. Some of the experiences are expected to be useful for planning remedial works of other areas. The following topics are presented with technical details:a.initial distribution of mercury in the bottom sediment,b.monitoring system design and monitoring committee,c.dredging work with specially designed vessels,d.sand capping over reclaimed sediment for confinement,e.residual mercury after dredging.

Economic considerations were important, but we gave a higher priority to safety. For the remediation, we had to usei every possible technique in order to minimize secondary pollution.
Pollution Measurement Accuracy Using Real Time Sensors and Wastewater Samples Analysis
Authors: Ruban G. , Marchandise P. , Scrivener O.
Published: May 2018

This paper deals with a comparison of the pollution measurement accuracy between real time pollution sensors (especially Suspended Solids - S.S.- determination by turbidimetry) and standard samples analysis on raw wastewaters. The two methods are used in commonly favourable conditions.

Considering separate measurement errors, the S.S. random errors of the two methods are in the same order of magnitude (about ± 25% for a 90% confidence interval), but sampler/analyses lead to a systematic underevaluation of about 17%. These rather high figures for the sampling/analyses method are due to the cumulation of samples compounding and preservation errors.

The determination of the samples collection error when estimating pollution loads is based on a set of 12 rainfall events registered during a 5 month study on a combined sewer overflow. Due to an optimized sampling strategy, the use of a 24 bottle sampler shows an average S.S. load underevaluation of only 5%, compared with the continuous estimation of the pollution sensor considered as a reference.

Real time pollution sensors can, therefore, be considered as convenient systems for field experiments where particulate pollution is of special interest, which is the case for runoff waters. Besides which, they are particularly suitable for the control and automation of sanitary transport and treatment equipment, being easily integrated into computerized systems.
Dynamic Model Simulation and Verification of a Two-Stage High-Rate Anaerobic Treatment Process with Recycle
Authors: Keller J. , Romli M. , Lee P. L. , Greenfield P. F.
Published: May 2018

The effect of overload on a two-phase high rate anaerobic wastewater treatment system with recycle was determined experimentally and simulated dynamically using a structured model. The experimental system consisted of a well mixed continuous reactor, controlled at pH 6 by sodium hydroxide addition, as the acidification stage and a fluidized bed reactor for the methanogenic stage, with an additional recycle connection from the second to the first reactor. Step changes in the feed concentration as well as in the feed flow rate were investigated and compared to simulation predictions. Operation without recycle was modelled accurately, with the simulation data of most process variables matching the experimental results quantitatively. The application of the same model to recycle operation showed significant discrepancy between the experimental and simulated data for the sodium hydroxide consumption rate and the gas flow rate in the acidification reactor. Although the actual values were different, the qualitative responses of the experimental and simulated step changes were similar. Other simulated variables showed good agreement with the experimental measurements. The model provides a useful tool for design and control studies in systems without recycle and, with some modification, for operation with recycle.
On-Line and Off-Line Expert Systems for the Operation of Wastewater Treatment Plants
Authors: Ladiges Gösta , Kayser Rolf
Published: May 2018

To provide the operators of wastewater treatment plants with the required knowledge to operate their plant both an on-line and an off-line expert system were developed. The on-line system recognises plant failures from on-line signals and laboratory measurements, immediately starts the diagnosis and gives proper advice displayed on the screen without controlling the plant directly. The off-line system is used for the diagnosis of plant upsets as well as for plant operation and the choice of control parameters. Both expert systems are PC-based and are applied to nutrient removing municipal treatment plants. They contain rules and models for nitrogen- and phosphorus removal, sludge losses, sludge bulking and the on-line control of different plant functions.
Stable Combustion in Sludge Melting Furnace by Fuzzy Logic Control
Authors: Shiono Shunichi , Usui Takashi , Iriyama Morio , Suzuki Kazuyuki , Naka Yohta.
Published: May 2018

This paper discusses combustion control using fuzzy logic for a sewage sludge melting furnace. The sewage sludge melting process is gaining attention as an effective method for reducing sludge volume. The slag from molten sludge is stable, causes no pollution, and can be used as a by-product. However, the operation of a sludge melting plant requires expert operators who have to deal with complex phenomena that take place in a melting furnace. In an effort to facilitate the operation, the authors have employed a control system which features the use of fuzzy logic for automatic combustion control in a cyclone type sewage sludge melting furnace. Confirmation was made that this fuzzy logic combustion control system functioned effectively for controlling the furnace temperature, O2 concentration in the furnace outlet flue gas, and concentration of NOx.
Biological Early Warning Systems for Toxicity Based on Activated Sludge Respirometry
Authors: Temmink H. , Vanrolleghem P. , Klapwijk A. , Verstraete W.
Published: May 2018

The proper operation of the activated sludge process is endangered by toxic spills in the wastewater that has to be treated. Therefore there is a need for so called biological early warning systems (BEWSs) that can detect toxicity for the activated sludge process and allow operators to take protective actions.

Two independently developed BEWSs are described and evaluated. Both systems are based on the on-line measurement of the respiration rate of activated sludge taken from the plant to be protected. Their practical implementation however is different with respect to the way the suspicious wastewater is brought into contact with the sludge. It is illustrated what the consequences of the design choices are with respect to the sensitivity, the response time and the positioning at the treatment plant of these BEWSs.
On-Line Estimation of the Respiration Rate in an Activated Sludge Process
Authors: Carlsson Bengt
Published: May 2018

In this paper, a novel approach to estimate the respiration rate in an activated sludge process is developed. The proposed estimator for the respiration rate is simple to implement and can be used during normal closed loop control of the dissolved oxygen. The basic idea is to use a two step procedure where in the first step, a model of the oxygen transfer rate KLa is estimated from a data set. The nonlinear KLa function is modelled with a static, constrained, piecewise linear model. In the second step, the respiration rate is estimated from measurements of dissolved oxygen concentration and air flow rate using the KLa model obtained in step 1.
Development of the Ammonia Biosensor Monitoring System
Authors: Tanaka H. , Nakamura E. , Hoshikawa H. , Tanaka Y.
Published: May 2018

The ammonia biosensor system was newly developed for monitoring ammonia in a river and in secondary effluent from a wastewater treatment plant. The detector of the ammonia biosensor is nitrifying bacteria immobilized by two acetic cellulose membranes and the transducer of the sensor is a dissolved oxygen probe. The microbial probe performs excellent selectivity and quick response to ammonia although control of pH with a phosphate buffer solution and control of temperature with an isothermal water bath are required. The developed ammonia biosensor system processes automatic calibration, sampling, and measurement as a monitor in the field. Accuracy and reliability of the biosensor system were also demonstrated by field tests accomplished at a wastewater treatment plant and at a river quality monitoring station.
POLLUTION PREVENTION AND POLITICS — THE RECENT EXPERIENCE IN SYDNEY
Authors: O'Loughlin G. G.
Published: May 2018

The New South Wales State Government has embarked on a multi-billion dollar programme of pollution abatement in Sydney, The socio-economic and political factors which have prompted this are described, These illustrate the complexities of dealing with pollution problems while social values alter, public organisations experience administrative change and financial pressures, and politicians try to balance environmental and economic objectives, The technical progress of the Sydney initiatives to reduce storm water runoff and sewer overflow pollution is also outlined.
INFILTRATION STRUCTURES IN TOKYO
Authors: Fujita Shoichi
Published: May 2018

Infiltration of stonnwater is now being adopted extensively in various locations throughout Tokyo. The main objectives of infiltration in urban areas are runoff control and groundwater enrichment. The techniques for planning. designing. construction. and maintenance were established, and then the effects of infiltration were proved. This paper will introduce some examples of infiltration structures in Tokyo. All footpath pavements in Tokyo have been changed to permeable pavement. Some of the porous concrete blocks now are made from incinerated sewage sludge or slag of melted sewage sludge. Residents cooperate to construct soakaways in their own housing areas at their own expense. The infiltration trench is so effective that it is used in various locations such as housing sites, housing complexes, streets, school grounds, public gardens. The storage tank can be constructed in a housing complex, thus stored stonnwater can be effectively used for toilets, sprinkling, car wash, and for a recreational pond. The reduction of stonnwater runoff by infiltration facilities is also greatly effective in preventing contamination of receiving waters.
INTEGRATED PLANNING OF IMPROVEMENTS OF SEWER SYSTEM AND TREATMENT PLANT FOR SUBURBS OF COPENHAGEN
Authors: Hansen O. B. , Pedersen J.
Published: May 2018

An integrated planning study for improvements of sewer system and treatment plant for a catchment in western Greater Copenhagen is presented. Alternative improvements of the total system are analysed using a mathematical model for the runoff in the sewer system taking into account the interdependencies between sewer system and treatment plant. The most cost-effective solution was identified through optimization of the hydraulic capacity of the treatment plant. The improvements of the selected solution consist of a realtime control (RTC) system for the combined sewer network, elimination of faulty connections to the separate sanitary sewer system, rehabilitation of untight sewers and extension of the treatment plant to meet stricter effluent criteria. The study was implemented as an interdisciplinary excercise between specialists in the fields of sewer modelling, sewer rehabilitation and waste water treatment.
SEWER SYSTEM ODOUR CONTROL IN THE LAKE BALATON AREA
Authors: Jobbágy A. , Szántó I. , Varga Gy. I. , Simon J.
Published: May 2018

In order to stop eutrophication and protect the water quality of Lake Balaton, the canalization and wastewater treatment system was redesigned in the late 70 s. Hence, regional sewer systems leading to sub-central treatment plants were established. Long retention times and long pressure sewer section, however, combined with the high sewage temperatures created a new environmental problem: the production of odorous and corrosive compounds such as hydrogen sulphide. In the present study, a preventive procedure to control anaerobic biodegradation processes in the sewage has been developed. It is based on the metabolic advantage of nitrate reduction over sulphate consumption. In a model experiment, problems deriving from the inappropriate application of nitrate addition were discovered, e.g. decreasing effectiveness by initiating undesired attached microbial growth, and denitrification and subsequent sludge loss in the secondary clarifier. The main concern of the system-specific procedure developed is to avoid local and general nitrate overdosing by an optimum arrangement of the dosing stations. This cost-effective procedure which prevents odour and corrosion problems has been successfully implemented in the Lake Balaton area.
THE COLMATION OF LEAKS IN SEWER SYSTEMS DURING DRY WEATHER FLOW
Authors: Rauch W. , Stegner Th.
Published: May 2018

This paper examines the performance of infiltration of wastewater into the groundwater due to leaks in sewer systems. Experiments were carried out under a variety of conditions using domestic sewage and uniform bedding material ranging in grain-size from 0 to 40 mm. The results indicate that the infiltration is determined solely by the physical process of the colmation of the bedding sand zone. Due to the accumulation of particles in the porous media the permeability of this zone and therefore the amount of infiltrated sewage is decreased rapidly with time. This effect is commonly known as colmation. A strong influence of both solids concentration of the sewage and grain-size of the bedding material can be seen on the temporal development of the colmation. Still a steady state flow was reached under all experimental conditions in less than an hour of infiltration. The characterisation of the colmated zone by the leakage factor presents the possibility to calculate the infiltrated sewage according to Darcy's law. The infiltration of sewage into the groundwater is therefore linear dependent on the area of the leak and the pressure head. The observed values for the steady state leakage factor range between 0.001 and 0.01 1/s depending mainly on solids concentration and grain-size.
MONTE CARLO MODELING OF WATER AND SEDIMENT CONTAMINATION BY TOXIC METALS AT THE NORTH AVENUE DAM, MILWAUKEE, WI, USA
Authors: Novotny Vladimir , Feizhou Lai , Wawrzyn William G.
Published: May 2018

A deterministic water - sediment quality model was developed with a Monte Carlo interface and input generation. The model was used to simulate water and sediment (total and dissolved-pore water) quality of a reach of Milwaukee River that includes an urban impoundment. The sediments in the impoundments are contaminated by toxic metals and other priority pollutants.

The sediment - water quality model was composed of three sequential segments each represented by three systems: water, upper sediment and lower sediment layers. The mass balance of the sediment contaminants was strongly affected by the direction of the groundwater fluxes through the sediments. Steady state was assumed for the water column and the upper sediment layer while a dynamic mass balance model was used for the lower sediment layer.

The inputs of the Monte Carlo simulation were ten years long time-series of upstream flows and Combined Sewer Overflow (CSO) discharges with corresponding Monte Carlo generated concentrations. The model calculated output concentrations which were statistically similar to the probability distribution of measured concentrations.
A KNOWLEDGE-BASED DECISION SUPPORT SYSTEM FOR SELECTING SMALL-SCALE WASTEWATER TREATMENT PROCESSES
Authors: Okubo T. , Kubo K. , Hosomi M. , Murakami A.
Published: May 2018

A PC-based decision support system was developed for selecting the most appropriate small-scale wastewater treatment plant process for a given set of conditions (e.g., population and available budget for facility construction and operation and maintenance (O&M)). The system consists of: (i) a numerical database for considering treatment performance and costs, (ii) a non-numerical database (knowledge-base) for considering intangible, empirical information (e.g., O&M difficulty), (iii) an analysis module for determining effluent water qualities and costs according to the basic user-input data of an objective site, and (iv) a dialog module for controlling user input and the subsequent system output. The system provides a display listing the effluent water qualities (e.g., BOD, total nitrogen, and total phosphorus), construction and O&M costs, and a ranking score of O&M difficulty and other non-numerical parameters of each treatment processes. The user is able to sort the resultant list according to parameter values or ranking score, and can prioritize several treatment processes using the analytic hierarchy process (AHP) method. In addition, the system is capable of evaluating integrated wastewater treatment processes which combine natural purification processes such as streams or wetlands.
ON-LINE FLUX-THEORY BASED CONTROL OF SECONDARY CLARIFIERS
Authors: Balslev Peter , Nickelsen Claus , Lynggaard-Jensen Anders
Published: May 2018

A strategy for controlling secondary clarifiers during dry weather and rain is described. The strategy is now implemented and is being tested on a full-scale wastewater treatment plant. The plant - Aalborg West Wastewater Treatment Plant - is operated by using the patented Biodenipho process.

The flux theory as formulated by A. Vesilind, in combination with measurements of sludge level, suspended solids and flow at critical points, form the bases for a dynamic on-line control of the clarifiers. The settling velocity used in the flux theory is measured and calculated on the basis of the installed sensors. In the test period it is expected that the control strategy will show capability of several improvements compared to traditional control strategy. The dry weather strategy should result in a reduction of return sludge pumping and thereby save energy. Moreover, improvement of the sludge characteristics is expected because of less pumping of sludge.

The rain strategy should show possibility of significant reduction in storm overflows in the plant and in the sewer system upstream to the treatment plant. Thereby the capacity of the plant will be improved and the total effluent load to the recipient reduced.