bluuebunny/crossref_metadata_2025_split huggingface dataset:
Field Evidence of Denitrification in Shallow Groundwater Flow Systems
Authors: Gillham R.W. , Cherry J.A. 
Published: March 2019

Abstract
A detailed hydrogeological study in a small agricultural watershed near Lake Erie in southwestern Ontario has provided evidence that denitrification is widespread in shallow groundwater in this area. In the groundwater zone of the unconfined sandy aquifer that underlies the study area, NO3- concentrations within two metres of the water table are commonly between 5 and 50 mg/1 (expressed as N). At greater depth, however, NO3- concentrations are generally less than 0.02 mg/1. The aquifer varies in thickness from 3 to 10 m. The transition zone between the high nitrate zone and the low nitrate zone is very thin. In the high nitrate zone, dissolved oxygen occurs at concentrations above 2 mg/1 , methane is absent, and Eh values obtained by the platinum electrode method are greater than 300 mV. In the low nitrate zone, dissolved oxygen occurs at levels less than 2 mg/1, methane is present, and Eh values are generally between 50 and 200 mV. The hydrogeologic conditions are such that it is very improbable that these trends are due to different groundwater sources. The data support the hypothesis that denitrification is the cause of the lack of NO3- in the deeper part of the aquifer. Nitrate and dissolved oxygen data from shallow groundwater zones in four other agricultural watersheds in southwestern Ontario support this conclusion.
Simulation of Advanced Wastewater Treatment Systems
Authors: Lam P.T. , Farquhar G.J. , McBean Edward A. 
Published: March 2019

Abstract
Simulation models for advanced wastewater treatment system component processes were identified or developed as necessary. They were used to simulate the performance of existing systems including lime treatment, ammonia stripping, recarbonation, filtration and carbon adsorption. Comparisons between predicted and measured effluent properties were reasonable. The component models were combined into an integrated model and used to simulate the operation of the Santee Project advanced wastewater treatment system. Simulations were again reasonable. It was concluded that the combined model could be used to provide realistic estimates of system efficiency response to variations in input parameters.
Identification of Groundwater Discharge Zones in a Reach of Hillman Creek in Southern Ontario
Authors: Lee David Robert , Hynes H.B.N. 
Published: March 2019

Abstract
Several new techniques were used to identify zones of groundwater and contaminant inflow to the headwaters area of a small stream draining an agricultural watershed in southwestern Ontario. Along a 3 km length of stream, seepage meters were used to measure and collect seepage flux and mini-piezometers were used to measure piezometric head relative to the stream and to collect pore water 0.6 m below the streambed.
Measurement of seepage flux at 43 locations along a 3 km segment of Hillman Creek showed that most of the study section was a groundwater discharge zone. Spatial differences in seepage flux ranged from less than 0.001 to nearly 9 cm m s 1. During the growing season there was a marked diurnal change in seepage rate at several locations and this was also reflected by a corresponding change in stream discharge.
Paired samples, one from a piezometer 0.6 m below streambed and one from the adjacent seepage meter, were significantly correlated (P &lt; 0.01) with respect to specific conductance, chloride and inorganic carbon concentration. This suggested that in many instances site-specific estimates of chemical inputs from groundwater to surface water can be estimated quickly without the necessity of allowing natural groundwater flow to flush out the water initially trapped within the seepage container. Seepage meters can be used to measure seepage flux and the small piezometers can be used to obtain samples. The concentrations of non-conservative solutes (organic carbon, nitrate + nitrite nitrogen, and phospate) in seepage meter samples were not significantly correlated with the concentrations in corresponding mini-piezometer samples.
Improving the Performance of the Activated Sludge Process: A Time Controlled Flow Equalisation Basin
Authors: Thérien N. , Marcos B. , Muratet G. 
Published: March 2019

Abstract
The performance of a time controlled flow equalisation basin in minimizing the mean daily concentration of organic substrate flowing out the clarifier unit has been investigated. This was done considering fluctuations in both the flowrate and organic content of the entering raw water stream to an activated sludge process.
A differential model apt at describing the dynamic behaviour of the activated sludge process of an existing wastewater treatment plant for periods of one to several days has been used. The control strategy, consisting in finding how much wastewater to pump in time from the basin to the aeration unit has been designed using iteration in control vector space with a second order minimization algorithm based on the concept of dynamic programming.
Situations for which this procedure would lead to an optimal control policy are discussed and an actual case of this occuring is shown for the data gathered at the plant.
The results obtained are also compared to more conservative and known control policies for the operation of an equalisation basin.
Process Development for the Removal of Radium-226 from Uranium Mining and Milling Effluents
Authors: Huck P.M. , Wilkinson P. , Averill D.W. 
Published: March 2019

Abstract
This study examined physica]-chemica1 processes for the removal of 226Ra from uranium mining and milting effluents. Following batch optimization experiments, a bench scale continuous-flow process consisting of precipitation, coagulation, flocculation and sedimentation was designed and tested. The continuous-flow process produced an effluent containing total 226Ra activity levels below 10 pCi/L, thus meeting the study objective, although a relatively low clarifier overflow rate was used. The filterable radium results from continuous-flow operation confirmed the predictions made from batch kinetic data, but the filterable radium objective of 3 pCi/L was not met. The study indicated that a mechanically-based system might be feasible for the removal of radium from uranium mining and milling effluents. The bench scale data were used to design a continuous-flow pilot scale process for demonstration of the treatment technology developed.
Nappes d'huile: prediction de leurs deplacements comme agent efficace d'un plan de mesure d'urgence
Authors: Coupal B. , de Broissia M. 
Published: March 2019

Abstract
The movement of oil slicks on open waters has been predicted, using both deterministic and stochastic methods. The first method, named slick rose, consists in locating an area specifying the position of the slick during the first hours after the spill. The second method combines a deterministic approach for the simulation of current parameters to a stochastic method simulating the wind parameters. A Markov chain of the first order followed by a Monte Carlo approach enables the simulation of both phenomena. The third method presented in this paper describes a mass balance on the spilt oil, solved by the method of finite elements. The three methods are complementary to each other and constitute an important point for a contingency plan.
Mixing Design for Air Agitated Rectangular Tanks
Authors: Akhtar W. , Mathur G.P. , Dickey D.S. 
Published: March 2019

Abstract
Design equations have been developed to estimate liquid velocities and mixing times in air agitated tanks. Determination of the gas rate necessary for adequate agitation in a given geometry is possible with this information. Air agitation offers benefits of increased dissolved oxygen and cost effective mixing for some waste water treatment applications.
Empirical expressions for surface and bottom velocities, as a function of gas flow rate and tank geometry have been developed from laboratory measurements. Since neither statistical nor dimensional analysis of the laboratory results could prove conclusively the correct form of the velocity correlations, the different correlation forms were used to verify large scale velocity measurements. Only one of the three trial correlations correctly predicted large scale velocities. The importance of these velocity correlations is evident from experience with mechanical agitator design, which shows that liquid velocity is the appropriate design criterion for most similar applications.
Mixing times were measured experimentally in the laboratory and studied with a mathematical model. The model was an unsteady state mass balance containing convective flow terms with turbulent dispersion super-imposed on the flow. The velocities for the convective flow terms were calculated from the empirical velocity correlations. Estimates of the turbulent dispersion coefficients were investigated experimentally.
Because multiple velocity correlations and a computer model for mixing time are difficult to use when performing design calculations, empirical correlations for bulk velocity and mixing time were derived. Combined with a relationship for power input, the design correlations provide information necessary to determine operating conditions in large scale, air agitated tanks. The effects of tank geometry on air agitated design have been explored within a range of typical construction dimensions. Thus, the principal elements of a complete design approach to air agitated rectangular tanks are presented.
Development and Application of a Water Quality Model for Use in an Environmental Assessment
Authors: Halbert B.E. , Ibbotson B.G. , Scharer J.M. 
Published: March 2019

Abstract
A model was developed for application in an environmental assessment study to allow predictions to be made of future water quality trends with respect to alternative proposals for expanding uranium mining activities in Elliot Lake, Ontario. Four water quality parameters were determined to be of particular importance in the assessment and were the subject of detailed investigations. Results of the model simulations formed the basis for assessing alternative development strategies and identifying those strategies which were most compatible with protection of the environment.
Accumulation du mercure chez certaines especes de poissons du Lac Saint-Louis en aval de Beauharnois
Authors: Gamache P. , Valiquette Y. , Chodorowski A. , Pichet P. 
Published: March 2019

Abstract
Les teneurs en mercure de jeunes perchaudes (Perca flavescens) et de jeunes crapets-soleil (Lepomis gibbosus) capturés au lac Saint-Louis indiquent une variabilité élevée entre les individus. Le niveau d'accumulation du mercure varie selon les stations et les deux espèces étudiées et n'est pas directement relié au niveau de mercure dans les sédiments. Les niveaux moyens observés sont inférieurs à ceux déjà publiés pour des individus plus âgés de la même région, indiquant une accumulation avec l'âge. La teneur en mercure du cerveau chez le crapet de roche (Ambloplites rupestris) et le crapet-soleil varie avec la teneur moyenne dans le poisson.
Some Hydrodynamic Characteristics of Three-Phased Fluidized Beds
Authors: Hermanowicz S.W. , Ganczarczyk J.J. 
Published: March 2019

Abstract
Hydrodynamic behaviour of three-phase (gas-liquid-solids) fluidized bed was examined. Values of liquid dispersion coefficient and gas-to-liquid mass transfer coefficient were estimated. Both coefficients were independent of the liquid flow rate but highly dependent on gas flow rate. Dimensionless relationships were developed for both coefficients and the gas flow number. Gas transfer (aeration) efficiency was limited by the coalescence of gas bubbles. Gas slugging in the bed was observed and conditions of slug formation were investigated. Porosity of the bed higher than a certain critical value is required to prevent slugging in beds of small diameter.
The Influence of Benthic Biota on Copper Speciation and Distribution in Freshwater-Sediment Systems
Authors: Krantzberg G. , Stokes P.M. 
Published: March 2019

Abstract
An investigation was made of the effects exerted by benthic macroinvertebrate communities on copper speciation in sediments from a lake which is becoming acidified. In laboratory microcosms, benthic macroinvertebrate communities stimulated the flux of copper from sediment to water. The presence of the macro-benthos resulted in a redistribution of physico-chemical copper species within the sediment with a transfer from more strongly complexed forms (HC1 extractable) to adsorbed and cation exchangeable forms (MgCl2 extractable). The role of bio-turbation in copper transformations is discussed.
Effect of Spent Sulfite Liquor on Growth and Ethanol Fermentation Efficiency of Saccharomyces Ellipsoideus
Authors: Kosaric N. , Ho K.K. , Duvnjak Z. 
Published: March 2019

Abstract
The objective of this study was to evaluate the extent of inhibition of yeast growth and alcohol biosynthesis when spent sulfite liquor (SSL) was incorporated into growth media.
The liquor was pretreated by boiling, steam stripping or aeration in order to eliminate the factors causing growth inhibition. While these treatments did reduce the growth inhibiting effects of SSL, complete elimination of inhibition was not possible.
Adsorption of Trihalomethanes in Pilot Scale GAC Columns
Authors: Forsyth D.E. , Gammie L. , Bing-Song Xu , Huck P.M. 
Published: March 2019

Abstract
A four month pilot scale study was undertaken at the Buffalo Pound Water Treatment Plant near Regina, Saskatchewan to examine the removal of trihalomethanes and other organic substances from finished drinking water using three commercial granular activated carbons. Complete trihalomethane removals were achieved initially but percentage removals declined to low levels near the end of the study. THM removal occurred almost entirely in the top part of the columns. As the study progressed, levels reported at intermediate sampling ports were lower than those in the effluents. In addition, the lower portions of the column were unable to remove THM's once removals began to decline in the upper portions, suggesting premature exhaustion of the lower column segments. The results suggest that for carbon types and raw water conditions similar to those of this study, activated carbon contactors for trihalomethane removal should consist of shallow beds.
The Calibration and Evaluation of Dissolved Oxygen Sensors in an Activated Sludge Plant
Authors: Speirs G. , Chapman D. , Luxon E. , Matthews J. 
Published: March 2019

Abstract
The performance of three types of dissolved oxygen (DO) sensors was evaluated in a pilot scale activated sludge plant. As the instruments were interfaced to a minicomputer, a curve fitting technique was developed to compensate for instrument non-linearity. Weighted regression was performed to update initial calibrations.
Fouling due to the microbial growth on the surface of the probe was the principal cause of decline in sensor performance with time. The rate of fouling depended on the type of sensor used, the mode of operation, the frequency of maintenance and the velocity of fluid past the probe. A number of alternatives were evaluated for reducing or compensating for the effects of fouling and other causes of inaccuracy.
To determine the suitability of sensors for tracking DO concentration during non-steady state tests for determining overall mass transfer coefficients (KLa), the probes were subjected to repeated step changes in DO concentration. First-order time constants (τ) for the sensors were estimated based on the results of each step.
Treatment of Landfill Leachate by an Anaerobic Filter Part 2: Pilot Studies
Authors: Henry J.G. , Prasad D. , Scarcello J. , Hilgerdenaar M. 
Published: March 2019

Abstract
A 4-month study of pilot-scale anaerobic filters was conducted on the treatment of leachate generated from the Beare Road Landfill site in Metropolitan Toronto. The study examined filter performance in both upflow and downflow modes of operation using two types of support media, via plastic biorings and granite stones. No significant difference in removal efficiences, quantity of gas produced and its methane content, was found between upflow and downflow anaerobic filters nor between the plastic biorings and the granite stone media. An efficiency of 66-72% COD removal was achieved at a hydraulic detention time as low as 12 hours. The total gas production ranged between 400-500 L/kg COD destroyed. Methane content in the gas remained between 80-84%.
Extended Solids Residence Time Decreases Biosludge Disposal Volumes from an Oil Refinery Activated Sludge Plant
Authors: Gurak R.S. , McKillican W.B. , Uppal A. 
Published: March 2019

Abstract
At Imperial Oil, the activated sludge process (ASP) is used to treat oily process water streams. Recent pilot studies at Imperial Oil Research demonstrated that extended solids residence time (SRT) in activated sludge processes is achievable by controlling the biosludge waste rate from the aeration basin. This method was successfully commercialized at Imperial's Sarnia Refinery. Results to date show that the extended SRT operation has led to a reduction in biosludge disposal volumes and has eliminated one half of the digestion requirements. Overall, the effluent quality has been improved. The effluent contaminant levels continue to be lower than both the Federal and Provincial discharge guidelines for Refinery process waste waters.
Acute Toxicity of Cadmium, Copper, Mercury and Zinc to Chydorus Sphaericus (Cladocera) from Three Quebec Lakes
Authors: Lalande Marc , Pinel-Alloul B. 
Published: March 2019

Abstract
Most experiments on the effects of pollutants on zooplankton have been done with laboratory-cultured Daphnia species, but relatively few have been based on the naturally-occuring crustaceans. This study deals with cultures of Chydorus sphaericus, a cladoceran from three Quebec lakes (one polluted lake and two nonpolluted lakes), in a comparative toxicity test involving four heavy metals. Experiments were performed according to a static toxicity protocol, using at least five concentrations per test, five replicates per concentration, ten organisms per replicate and 200 ml volumes of metal solutions. The 48-hr EC50 of each individual metal and of the combination of metals were determined for each culture and for different size classes. The overall toxicity trend is : mixture &gt; Hg &gt;&gt; Cu ≥ Cd &gt; Zn. Juveniles appeared to be more sensitive than adults to heavy metals, but the observed differences were not statistically significant. Contrary to expectation, cultures from nonpolluted lakes showed higher EC50 mean values than the strain originating from a polluted lake.
Aluminum Speciation and Movement in Three Small Watersheds in the Southern Laurentians
Authors: Hendershot V. H. , Lalande H. , Dufresne A. 
Published: March 2019

Abstract
A study of three forested watersheds in southern Quebec shows that stream water chemistry, in particular the concentration of reactive Al, is dependent on the flowpath of water, Analyses of soil solutions and stream waters are used to identify the source of water under different streamflow conditions. During periods of baseflow the water flows through deep soil horizons, or bedrock, and very low concentrations of reactive Al are measured in the streams. During stormflow, generated by heavy rainfall, the pH decreases and the amount of soluble Al increases, Although very high levels of total reactive Al were measured (a maximum of 635 µg/L), the amount of uncomplexed, monomeric Al remained low; in only one of the basins did the concentration exceed the 200 µg/L level where Al toxicity to fish becomes a severe problem.
The Fate of 3-Trifluoromethyl-4-Nitrophenol (TFM) in Quiescent Waters and Its Impact on Benthos
Authors: Scott Brian F. , Carey John H. , Nagy Elmer , Dermott Ronald 
Published: March 2019

Abstract
The lampricide, 3-trifluoromethyl-4-nitrophenol (TFM), was added to three lined, sedimented ponds to determine the fate of this chemical and its effect on the benthos of quiescent waters. Two ponds were treated with the commercial formulation and the third was treated with purified TFM. Water column, sediment and benthos samples were taken regularly but not necessarily simultaneously. The initial distribution of TFM in the water column was monitored as was the rate of disappearance of TFM which was calculated to be 0.068 day-1.
Appreciable concentrations of TFM were found in the sediment over the two weeks following treatment, with only trace concentrations detected 117 days after treatment. No known decomposition products of TFM were detected in the water or sediment samples. Only the oligochaete and mollusc populations decreased after treatment, but they had returned to levels in the control pond within a year after addition of the chemical.
Identification of Taste and Odour Compounds from Western Lake Ontario
Authors: Brownlee B.G. , Painter D.S. , Boone R.J. 
Published: March 2019

Abstract
During August, 1983 geosmin was identified in a municipal water supply drawn from western Lake Ontario. The geosmin concentrations were 0.01-0.07 μg L-1, within the range for threshold odour concentration of 0.01-0.2 μg L-1. 2-Methylisoborneol was not detected. The odour 'event' coincided with a dieoff of Cladophora in the lake, but we were not able to establish a direct link between the dieoff and geosmin production. Decomposing Cladophora in shoreline areas produced a strong odour in the air. 3-Methylindole, elemental sulfur, dimethyl tetrasulfide, and dimethyl pentasulfide were tentatively identified in water samples collected from these areas, but geosmin and 2-methylisoborneol were not detected.
Chemical Speciation of Long-Lived Radionuclides in a Shallow Ground Water Flow System
Authors: Champ D.R. , Young J.L. , Robertson D.E. , Abel K.H. 
Published: March 2019

Abstract
The chemical speciation, ionic plus particulate forms, of long-lived isotopes of Pu, Am, Cm, Cs, Sr, Ni, I, and Tc was determined in four contaminant plumes at the Chalk River Nuclear Laboratories. Comparative data were also determined for shorter-lived isotopes of Ce, Eu, Fe, Co, Ru, Zr and Sb. Anionic species were the predominant solution species, and hence the mobile form, for many of the elements. Complexation by organic ligands, both natural and synthetic, was postulated to be important in mobilizing Co, Ce, Cs, Eu, Sb, Zr, Fe, Ni, I, Pu and possibly Am. Thermodynamically-predicted aqueous speciation was consistent with our data for only four elements; Ru, Sr, I and Tc. The chemical speciation of Am was found to be particularly anomalous in the study sites. On the basis of our data we conclude that the predictions of Kd-based models for radionuclide mobility must be carefully evaluated with respect to the adequacy of the speciation assumptions of the Kd approach.