Fluoride concentrations in the Montreal Urban Community's untreated wastewater were analyzed in an attempt to evaluate their levels and seasonal variations. Continual hourly monitoring of the raw sewage, between June 1992 and May 1993. yielded average monthly fluoride concentrations between 0.072 mg/L and 1.984 mg/L, with an annual mean of 0.45 mg/L. Daily variations and frequency distributions showed a wider range of fluoride levels, with the maximum values possibly reaching as high as 4-fold the mean and well over 2 orders of magnitude higher than the minimum values. This suggests that significant massive point discharges occur in the sewer network. Daily monitoring of the precipitation showed that the mean fluoride concentration in liquid precipitation generally fluctuates between 0.030 mg/L and 0.741 mg/L, whereas the average fluoride specific mass in dry precipitation ranges between 0.096 kg/km$ sp2$ and 2.775 kg/km$ sp2$. Seasonal trends have been depicted for fluoride levels in both the raw wastewater and the precipitation. Groundwater sampling yielded an average fluoride concentration of 0.13 mg/L, and analysis of the melting salts used by the City revealed that these do not contain any fluoride. Data from the City's water treatment plants showed that the average fluoride concentration in their raw water is 0.20 mg/L. This is in contrast to the value of 0.13 mg/L used in the literature. Mass balance analyses have shown that the mass of fluoride resulting from infiltration and non-fluoridated waters, as well as that due to the domestic habits of the population constitute, among the identified sources, the major input of fluoride mass into the wastewater. Nevertheless, unidentified sources of fluoride, consisting essentially of industrial discharges, still account for the largest portion (${ approx50 %}$ of the total) and contribute, as an annual average, 375 kg/day.

The first objective of this research was to evaluate oxidation-reduction potential (ORP) as an indicator of effective iron removal in a biological process and to determine its relationship to dissolved oxygen (DO) and residual iron in the filtered water. Biological removal of iron to produce drinking water was established on one full-scale and two pilot-scale plants at two sites in France. Results show that below a minimum DO concentration of approximately 0.3 mg/L, residual iron concentration was related to ORP in the filtered water. Above the minimum DO requirement, ORP on the order of approximately 500 mV consistently reflected effective iron treatment and residual iron concentrations less than the French norm for potable water of 0.2 mg/L. / Secondly, two catalytic materials of filtration known as Ferrolite MC2 and Purolite were investigated on pilot-scale for their capacity to oxidize iron and manganese. Results showed that both materials eliminated dissolved iron to below detection levels regardless of DO or filtration rates up to 15 m/h (Ferrolite MC2) and 20 m/h (Purolite). During the trial period where no filter regeneration was carried out, the elimination of dissolved iron and dissolved manganese, respectively, were 100% and 77% for Purolite and 100% and 65% for Ferrolite MC2 for a raw water with 3.47 mg/L of dissolved iron and 0.317 of dissolved manganese. Purolite filtered a total volume of 1127 L or 137 L/kg of catalytic material and Ferrolite MC2 filtered a total of 1457 L or 217 L/kg.

This thesis studied the effect of chlorination disinfection by-products (CDBPs) in drinking water on the risk of developing pancreatic cancer. The study was based on the case-control component of the National Enhanced Cancer Surveillance System. Incident cases and frequency-matched population controls recruited between 1994 and 1997 from six Canadian provinces were used to estimate pancreatic cancer risks associated with exposure to CDBPs. Residence history collected from subjects was linked to two sources of water quality data to estimate historical exposure. The first source provided a lifetime average estimate of known exposure to trihalomethane (THM), bromodichloromethane (BDCM), and chloroform (TCM), while the second provided residence-specific estimates of THM exposure. Adjusted risk estimates were based on the most recent 30 years of exposure with missing data imputed using Observed Control Mean Imputation. Overall, no consistent significant increase (or decrease) in pancreatic cancer risks was observed with 30-year exposure to THM, BDCM, and TCM after adjusting for potential confounders.

Since the early 1980's, leachate originating form the Alice and Fraser municipal landfill has been discharging in a natural marshland system located some 300 meters downgradient form the waste disposal site. However, monitoring of the water quality within the marshland indicates that the contaminant level has not yet surpassed background concentration downstream from the main impact area. A mathematical model was developed in an attempt to predict the mobility of several contaminant species within the marshland environment. Parameters needed for the predictive model were gathered based on the physical configuration of the landfill and marshland associated with laboratory derived data on the attenuation capacity of the marshland soil matrix. The behavior, transport and ultimate fate of contaminants in organic soil is greatly affected by their participation in sorption reactions. The adsorption potential of lead, zinc, calcium, sodium and pentachlorophenol (PCP) by marshland soil was evaluated in laboratory through both, batch and column experiments. A multidimensional finite-difference model based on the Advection-Dispersion Equation was used to predict the migration of the above mentioned contaminants. (Abstract shortened by UMI.)

No description available.

The respiration rate has generated much interest as a means of monitoring and controlling the activated sludge process because it is directly associated with both biomass growth and substrate removal. Respirometry has long been recognized as a valuable tool for controlling the activated sludge process, and as a result, many respirometry-based control strategies have been proposed in the literature. This study has developed a benchmark and methodology for conducting simulation studies to test the proposed control strategies within a complete and consistent set of process conditions. The benchmark consists of a complete set of influent conditions, a standard activated sludge plant configuration, models for the activated sludge process and the secondary clarification process, as well as values for the model parameters and initial values for the state variables. The benchmark provided the framework for the development of the simulation-based methodology. The methodology uses the benchmark, and includes a set of guidelines for implementing a control strategy in the benchmark plant and a set of tests for evaluating the performance and benefits of a proposed control system. The benchmark and methodology were then applied to test selected control strategies from the literature. (Abstract shortened by UMI.)

The fear that contaminated leachate could escape from the Trail Road Municipal Landfill Site, and the need for a cost-effective on-site treatment alternative, has led to an evaluation of the options for treating the leachate. One treatment option being examined is the use of low-pressure reverse osmosis (RO), which is becoming increasingly attractive with the development of new technology. The purpose of this study is to evaluate the technical feasibility of this treatment process for synthetic and real landfill leachate. Membrane 'coupon' experiments were conducted to study three types of low-pressure membranes (supplied by Hydranautics, Fluid Systems, and Saehan Industries), to determine the membrane with the highest permeate flux and rejection capabilities, to conduct statistical analysis on the testing apparatus and to test how the selected membrane was able to cope with different concentrations of synthetic leachate at different operating pressures. Membrane 'coupon' experiments were conducted on the Hydranautics' membrane with actual Trail Road leachate to determine the effect of leachate concentration and operating pressure on the product flux and on the TOC, NH3, and the Cl-- removal efficiencies. Tests on Trail Road leachate samples were conducted with a lab-scale Hydranautics' spiral-wound membrane at operating pressures of 40, 50, and 60 psi (276, 345, and 413 kN/m2). (Abstract shortened by UMI.)

As a solution to the problems of municipal solid waste management, anaerobic digestion possesses the optimal combination of volume reduction, probability of success and potential for both energy and resource recovery. An innovative application of anaerobic processes is the co-digestion of sewage sludge and the organic fraction of municipal solid waste (OFMSW). The purpose of this study is to evaluate the technical feasibility of this process in the context of typical Canadian solid waste. Lab-scale experiments were initially conducted using one litre batch bioreactors operated mesophilically (37$\sp\circ$C) and fed a mixture of primary sludge (RAW), thickened waste activated sludge (TWAS) and simulated OFMSW. To facilitate organics solubilization, three pretreatments were evaluated: thermal, alkaline and thermochemical. Using a central composite experimental design, two factors were studied, the total solids content of the feed and its particle size. For all three pretreatments, second order empirical models were developed with respect to common indicators of metabolic activity, namely, biogas production, biogas methane concentration, soluble chemical oxygen demand (COD) removal and total and volatile solids reduction. (Abstract shortened by UMI.)

This research project consisted of studying the feasibility of a combined UASB-activated sludge process configuration for treating a dilute synthetic substrate, simulating a dairy wastewater, at a laboratory temperature averaging 23.5 +/- 0.8°C. The bench-scale experimental work was carried-out in two parallel biotreatment systems fed in series. They consisted of relatively small-scale Upflow Anaerobic Sludge Blanket (UASB) reactors of 3.85 and 3.75 L, respectively, followed by 2 L-activated sludge polishing processes. The feed concentration applied to one of the systems consisted of the minimum influent strength recommended for successful anaerobic treatment (∼1 000 mg CODt/L) while the second system was of the domestic sewage-strength range (∼500 mg CODt/L), achieved by dilution. The mainly soluble complex feedstock used consisted of tap water and Iron Fortified Enfalac(TM) Infant Formula. It was supplemented chemically to ensure that proper (N and P) nutrient requirements were met as well as to increase its buffering capacity and to adjust pH. Three experimental runs were carried out by applying increasing UASB influent flow rates of 2, 4 and 8 L/d, in both systems. (Abstract shortened by UMI.)

Wastewater treatment produces a large amount of contaminant-containing sewage sludge, disposal of which is of great concern and is tightly regulated. Anaerobic digestion of sewage sludge is used in most large-scale wastewater treatment plants prior to sludge end use or ultimate disposal mainly due to its advantages of low energy consumption and potential energy recovery. Thermal pretreatment has been studied and successfully applied to improve the quality of the digestion product. Microwave (MW) irradiation has become of interest with some advantages over conventional thermal pretreatment. The objective of this research is to investigate whether MW pretreatment can enhance the anaerobic digestion of primary sludge (PS). The influence of MW irradiation on the characteristics of pretreated primary sludge was studied in terms of MW intensity, sludge solid concentration, and temperature achieved. The experimental range of sludge of sludge characteristics was sludge solid concentration of 1-4% (w/v) total solids (TS), temperature 35-90°C, and MW intensity of 40 and 80%. MW irradiation was found to increase the concentration of soluble COD (SCOD) in the sludge. The ratio of SCOD/TCOD increased from 2.5% to around 6-7% for 4% TS sludge and MW pretreatment temperature of 90°C. Both sludge solid concentration and MW irradiation temperature were shown to be the most important MW pretreatment parameters in solubulizing primary sludge. MW intensity in the range of temperatures studied had no impact on primary sludge solubilization. Mesophilic biochemical methane potential (BMP) assays were applied to primary sludge pretreated at MW scenarios of 1-4% TS, temperatures 35-90°C, and MW intensity of 40 and 80%. Again, the BMP assay indicated no obvious difference in samples with the same TS concentration and pretreated to similar temperatures but at different MW intensities. Both higher MW pretreatment temperatures and higher TS concentrations significantly improved biogas production rate and reduced required digestion time to achieve 85% of ultimate digestion. For 4% TS primary sludge samples pretreated to 90°C, biogas production rate increased 37% or resulted in a 28% reduction in digestion time to achieve 85% of the ultimate biogas production. There was some indication that MW pretreatment may have caused some very mild inhibition of the whole (soluble and suspended) sludge sample based on the existence of a 2-3 day lag phase for pretreated sludge samples. While MW pretreatment increased the rate of digestion of primary sludge it resulted in no significant increase in the ultimate biogas production and biodegradation of organic matter in terms of VS and TCOD removal. Analysis of biogas production results from the BMP assays indicated that they could be described by a first order reaction. The reaction rate constant increased with increase of TS concentration and MW pretreatment temperature, but was not affected by MW intensity. BMP assay of the soluble fraction of pretreated primary sludge was carried out on 4% TS primary sludge pretreated at MW intensity of 80% and temperatures of 65°C and 90°C. The soluble fraction was shown to exhibit no methanogenic inhibitory effects. In general MW pretreatment at the conditions tested did not result in any significant microbial inhibition and resulted in increased rate of primary sludge digestion without increase of the ultimate degradability of the sludge.