Chemical coagulation of eighteen groundwater samples from the Santa Ana River Groundwater Basin was evaluated on the bench scale to determine its viability for treating these low quality groundwaters to current USEPA drinking water standards. The color and organic matter in both raw and treated water samples were characterized according to UV absorbance and DOC molecular weight fingerprints. Alum coagulation with 5 mg/L as Al successfully treated raw waters with color of up to 60 pcu and 190 mug/L THMFP to meet the standards of 15 pcu and 100 mug/L for color and THM, respectively. Variations of the coagulation process which showed merit were pH modification, pre-ozonation, and using a cationic polymer, Magnifloc 573C, as a sole coagulant. Coagulation preferentially removed high-molecular-weight material which was responsible for causing the greatest degree of color. These color bodies were not, however, responsible for the majority of the THMFP.

No description available.

No description available.

In this dissertation, the chemical oxidation of trace organic impurities by the treatment of UV light alone, ozone alone, and the combination of UV light and ozone in ultrapure water is discussed. Eighteen model compounds are chosen as the representative organic contaminants. Significant synergistic removal effect by the oxidation of the combination of UV light and ozone has been observed on all model compounds except for trichloroethylene, benzoic acid, and methionine. The removal efficiency by the oxidation of the combined treatment is observed to be greater than that by the oxidation of UV light alone or ozone alone for all model organics. Based on the same injected amount of contaminants over a given period of time, it is shown that the amount of leftover material after one cycle in the loop in a run with ozone injection is lower than that in a run without ozone injection for most compounds. The photolytic ozonation improves the TOC removal efficiency not only on the UV unit, but also on the loop removal performance. The chemistry, advantages and disadvantages of all those three oxidative methods are discussed. The mechanisms of oxidative reaction for the UV/ozone interactions and of ion exchange in the deionized tank are proposed. The rate coefficient of each reaction for model compound is determined by fitting the model prediction to the experimental data. The metrology for modeling the whole ultrapure water system has been established. The mathematical derivations for that metrology are given. For the purpose of paving the road for the reuse of rinsing wastewater, three cases simulating TOC dynamic responses are discussed, and the chemistry between HCl and organics under the treatment of UV light alone is studied. The combined UV/ozone reaction has been proven to be a better way in removing organic contaminants in terms of particles population number density. The mathematical equation of particle size reduction with its breakage rate and fragmentation distribution function is proposed and validated with the experimental data. It is concluded that the surface erosion is the pathway of size reduction when organic particles are oxidized.

Due to regulatory legislation enacted over the past few decades, the design of municipal sanitary landfills has evolved from simple open dumps to relatively sophisticated storage and treatment facilities. Bioreactor landfills, which were first introduced in the mid 1990s became a popular landfill management technique and. A bioreactor landfill uses leachate recirculation to enhance the degradation processes thus degrading the waste constituents much faster than would be experienced with arid landfills. However, the well-accepted set of design criteria and methods of analysis for stability, settlement, degradation, gas generation, and water infiltration that had been developed for the arid landfills were not necessarily appropriate for the bioreactor landfills. Whether due to leachate recirculation or extreme precipitation, the waste in a landfill may tend to become saturated. The high saturation levels then reduce the permeability of the waste to landfill gas thus leading to pore pressures that are greater than what would be predicted by fluid statics. In this case, the factor of safety for global stability within the landfill will be lowered, potentially creating failure. A theoretical model predicting the time and depth dependent development pore pressures due to the formation of landfill gas in a wet landfill is presented. The model is then quantitatively approximated with a finite difference scheme. It was found that below the level of saturation, the steady state pressure distribution appears to be hydrostatic except that the unit weight of the fluid is significantly heavier (14.0 kN/m³) compared to water (9.81 kN/m³). In the ten days preceding July 10, 2000, approximately 0.75 m (30 inches) of rain fell onto the Payatas Landfill near Manila, Philippines. Results of HELP modeling indicate that this precipitation caused a 10-m deep zone of saturated waste at the bottom of the waste mass. Through a back-analysis of the failure, a factor of safety of 1.0 for stability was calculated by using an increased unit weight of pore fluid of 20.9 kN/m³, which is similar to that predicted by the finite difference scheme of 14.0 kN/m³. Hence, this research shows that the build-up of landfill gas can play a significant role in the stability of wet landfills.

The characteristics of the single-sludge nitrification-denitrification process were investigated using influent organics as the carbon source and nitrate as an electron acceptor to see if any oxygen savings could be obtained. The key research tools used were mathematical modeling, computer simulation, the library, and discussions with experienced operating engineers. A mathematical model was obtained from the literature for the nitrification process. The summary of simulations using the model was that complete nitrification can be achieved at a temperature of 20$\sp\circ$C, with a dissolved oxygen concentration of 2 mg/l and a sludge age of 4-5 days. A mathematical model was developed for the single-sludge nitrification-denitrification process and the influence of denitrification on oxygen requirements was studied by simulation. The conclusion was that, depending on the COD/NH$\sb4\sp+$ ratio, savings in oxygen, by the use of nitrate as an electron acceptor are in the range of 3 to 8 percent.

Membrane distillation, a process in which vapor from a liquid feed passes through the pores of a hydrophobic membrane, was investigated as a possible technique for desalination and for the removal of ethanol, acetone and benzene from water. Three different membrane modules were used in the experiments examining the impact of operating variables upon permeate flux and quality. A mathematical model was developed and validated for the membrane distillation process. / In the desalination study, two modules with built-in condensing surfaces were used for conducting experiments on flat membrane sheets. The quality of the permeate, quantified by conductivity measurements, and the permeate flux were monitored as feed concentration, feed temperature, feed flow rate, cooling temperature, and cooling water flow rate were varied. The effect of the distance between the membrane and condensing surface was investigated by adjusting the air gap within one of the modules. The feed streams tested included sodium chloride solutions and artificial seawater. The membrane materials used were PVDF and PTFE. At optimal conditions, fluxes as high as 26 kg/m$ sp2$hr were obtained. In all experiments, the rejection factor was above 95.5%. / A flat-sheet cross-flow module was used to study the separation of dilute solutions of ethanol and acetone. The same operating parameters tested in the desalination experiments were varied for ethanol and acetone feeds. The upper feed concentrations tested were limited by the risk of membrane wetting to 10 wt% ethanol and 6 wt% acetone. Within the feed temperature range of $40 sp circ$C to $70 sp circ$C, ethanol selectivities of 2 to 3.5 and acetone selectivities of 2 to 6 were achieved. The maximum fluxes obtained were 2.15 kg/m$ sp2$hr for ethanol permeate and 2 kg/m$ sp2$hr for acetone permeate. / A mathematical model, based on first principles of heat and mass transfer, was developed and validated on the desalination, ethanol, and acetone experimental data. Good agreement between experimental and predicted values was obtained with the model version incorporating temperature and concentration polarization. / The possibility of using vacuum membrane distillation for treating water contaminated with volatile organic compounds was investigated by using benzene as a model compound. An experimental unit with polypropylene membrane tubes fitted within a polypropylene shell was used in the tests. Dilute benzene solutions were pumped through the lumen of tubular membranes while vacuum was applied to the shell side. The data obtained by varying operating conditions was analyzed in terms of the overall mass transfer coefficient based on the film theory. A comparison between the effectiveness of membrane distillation and air-stripping was drawn based on a published case study. The experimental unit with tubular membranes failed to compete but extrapolations to higher membrane contact areas showed promise for hollow fiber modules.

This project describes a methodology for developing a digitized GIS-based inventory of underground municipal utilities, and recommends an approach for developing a database, which will assist with considerably improved management of buried systems and effective use of limited available resources. The study also discusses the water and sewer infrastructure debt and the total infrastructure debt in Canada. Some other issues related to the Canadian water infrastructure, such as water pricing and consumption patterns, along with the deterioration mechanisms of the underground services, are also discussed. The study focuses on the main services of water supply and sewage systems in any Canadian municipality, which presently are in an advanced state of deterioration. The steps required to develop such an inventory are reviewed and suggestions are made for condition assessment of the system using non-destructive techniques, employing simple methods, as well as more sophisticated tests in critical sectors, where further investigation is required. These methods are also summarily revised. / The underground infrastructure of the McGill Downtown Campus is summarily described; it comprises the various underground features which exist in a small community, e.g. water-supply and sewage system, electrical lines, gas pipelines, telecommunication networks, etc., which are similar with Montreal's underground services, in terms of age, materials employed, workmanship and technologies available over the past 175 to 200 years. The framework for the underground infrastructure inventory is proposed for implementation in a small community such as the McGill Downtown Campus. / The long-term goal of the project is to extrapolate the McGill "model", and to enhance it such that the municipalities in Canada can implement it as a basis for development of GIS-based inventories and condition assessment, and prioritization for effective management of underground services, which include scheduling, financing and implementation of repair, rehabilitation and replacement of underground and other infrastructure.

Two 28 L continuously fed cyclically aerated sequencing batch reactors were operated at a constant sludge age and hydraulic residence time of 15 and 2, 3, 4 or 8 days, respectively, and an organic load of 7, 14 or 65 g of COD/day to investigate operation strategies to treat whey (a nitrogen unbalanced waste). The systems were equipped with a membrane filter that automatically removed effluent during the settling period. To observe performance, biomass appearance and settling behaviour under various nitrogen-limiting conditions, nitrogen was added at rates to maintain COD/N of approximately 20 to 60. / The cyclic aeration generated a selector effect in the sludge blanket and controlled bulking. The N-balanced system could be used without the membrane filter and effluent BOD and solids were below 20 mg/L and 25 mg/L, respectively. The effluent of the N-unbalanced systems had BOD below 20 mg/L but generated solids varying between 60 and 100 mg/L. The membrane filter significantly reduced the effluent solids. Moreover, the clarity of the filtrate was enhanced when the sludge bulked severely due to an excessive number of filaments.

This research is one of a group of studies which aims to evaluate the feasibility of disinfection using ultraviolet radiation (UV) at the Montreal Urban Community Wastewater Treatment Plant (MUCWTP), and to provide information to evaluate the level of disinfection required. The physico-chemically treated effluent is discharged into the St. Lawrence River. The downstream river is used for recreational purposes, particularly at Ile Evers (4 km downstream), which is occasionally used as a beach. / The distributions of fecal coliforms (FCs) in the river relative to their distribution in the effluent were assessed in terms of those that were particle-associated FCs in the river may affect the UV dose required to disinfect the MUCWTP effluent. Samples from strategic locations in the St. Lawrence River, and the MUCWTP effluent, were collected and analysed for FCs, total phosphorus (P$ sb{ rm T}$, suspended iron (Fe$ sb{ rm s})$, suspended solids (SS), turbidity and particle size distribution (PSD). The iron originates mainly from the iron (III) chloride which is added as part of the MUCWTP treatment process. (Abstract shortened by UMI.)