In North America, the activated sludge process is commonly used in wastewater treatment. However, there are many aspects of the process that elude researchers, in particular, those that will ensure a successful control and optimization of the process. Because of the biological nature of the activated sludge process, its characteristics are highly dependent on environmental factors and hence can be very difficult to control and manage successfully. A very important factor contributing to an optimized activated sludge plant is the experience of its operators with the activated sludge process. This is achieved through the use of a variety of tools including traditional classroom training, computer based training, expert systems and simulation tools. Some of the tools aim to help the new operators acquire this experience quicker while others aim to enhance the experience of seasoned operators. This project presents a premise that an integration of these tools will be an effective and innovative way to help the operators achieve their goals. Hence, a design of an Integrated Training and Decision Support System (IT-DSS) has been proposed, and parts of the prototype system have been built. Preliminary results showed that such an integrated solution is feasible and realisable although a fully functional system has yet to be realised due to the scope limit. The results of this project provided solid and valuable starting points for the completion of such a step, and they also further support the value of the integration approach that has been put forth.

The main objective of this study was to compare the total suspended solids (TSS) removal efficiency of a modified sedimentation tank to that of a conventional tank The experimental tank was designed for flow to pass over a series of inclined plates. It had a much shallower flow through zone and the inclined plates were situated just below this zone. The inclined plates were added to provide a quiescent settling zone for the falling particles and to act as a barrier to prevent scour of settled particles. A conventional horizontal flow sedimentation tank was also used in this study. The two designs were run in parallel and a highly concentrated clay suspension was passed through both tanks. The TSS concentrations of both the influence and effluent streams were measured. The response of both designs to different parameters such as sampling time, depth over the inclined plates, flowrate, inclined plates spacing and inlet TSS concentration was observed. The tank with the inclined plates (at the smallest spacing) proved to have an equal to slightly high removal efficiency and a slightly better reaction to the change of parameters. This tank also proved to have less dead volume than the control tank. Since the reduction in flow through volume proved to be as good and slightly better than the control tank the concept deserves further research. It has the potential to permit considerable tank depth reductions while retaining efficiency.

A dynamic model describing the simultaneous degradation of easily degradable substrates (sucrose and acetic acid (HAc)) and 2,4-dichlorophenol (2,4-DCP) in upflow anaerobic sludge blanket reactors (UASB) was developed. Two critical factors considered in the multiple substrate degradation processes were sorption and substrate interaction during degradation. Experimental investigations on the sorption of chlorinated phenols under dynamic situations as well as the degradation kinetics of cosubstrates and 2,4-DCP considering sorption and substrate interaction were conducted first. It was found that partitioning was the dominant mechanism in sorption of chlorophenols to anaerobic granules and that metabolically mediated diffusion during sorption was negligible. Under a dynamic situation, anaerobic sorption of chlorophenols which follow sorption linearity and sorption-desorption singulanty in isotherms, can be described by a dynamic model incorporating linear sorption equation. Nonequilibrium sorption caused by diffusion limitations in anaerobic reactors was found to be negligible because of the strong hydrodynamic dispersion that prevails in anaerobic reactors and the high porosity of anaerobic granules. However, rmnor nonideal sorption phenomena were observed for 3,4-dichlorophenol (3,4-DCP) and pentachlorophenol (PCP), both of which showed sorption-desorption isotherm hysteresis. Substrate interaction during degradation of cosubstrates and 2,4-DCP resulted in the inhibition of acetogenesis and methanogenesis by 2,4-DCP. The effect of electron donors on 2,4-DCP degradation was found to be minimal. A modified Haldane type inhibition function was proposed to described the degradation of 2,4-DCP. On the basis of model discrimination results, the degradation kinetics of HAc and propionic acid (HPr) were defined by the uncompetitive inhibition and Haldane type inhibition functions, respectively, with 2,4-DCP as inhibitor. Acidogenesis of sucrose to HAc or HPr followed the Monod equation since no inhibiting factor was found for this degradation process. Knowledge obtained from the above investigations was used to develop a dynamic model for UASB reactors. Data that were obtained from experimental investigations on multiple substrate degradation in continuous UASB reactors were used to validate and veritjl the dynamic model. The model predicts the system responses for 2,4-DCP, 4-monochlorophenol (4-MCP), HAc, HPr and chemical oxygen demand (COD) concentration in the effluent. Based on model fitting results, it was found that the degradation rates of 2,4-DCP and cosubstrates, HAc and HPr, changed inversely as a function ofthe specific organic loading rate ofthe UASB reactors. The implication ofthis finding was fully discussed.

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Aerated stabilization basins (ASB) were modeled to examine the effects of operational modifications on their abilities to remove organic chlorinated compounds and color from Kraft mill bleaching wastewater. Color was measured spectrophotometrically and organic chlorinated compounds were measured as total organic halide (TOX). Kraft mill bleaching wastes were treated in bench-scale bioreactors containing acclimated sludge from operating full-scale ASB's. Modifications were made to traditional ASB operations to determine the effects of mixing, anaerobic conditions, sequential anaerobic/aerobic conditions, and forced co-mingling of wastewater and sludge on TOX and color removal. Results were compared to traditional facultative aerobic conditions experienced in an ASB. Performance was determined in terms of percent removal, total removal, and specific removal based on biomass present.

Inhibition of biogenic acid production by thiobacilli was investigated by encouraging the growth of potential competitors. Two-organism competition experiments (Thiobacillus sp. vs. heterotrophic competitor) were conducted in a bench-scale, continuous-flow reactor. Results were sensitive to the influent ammonia/glucose ratio. Under nitrogen-limiting conditions, the cell concentration of T. thiooxidans or T. neapolitanus and acid production rates were reduced by about two orders of magnitude. Under carbon-limiting conditions, only modest reductions in the thiobacilli cell density and effluent sulfate were observed. In general, encouragement of microbial competition can interrupt acid production by thiobacilli and may inhibit crown corrosion in concrete sewers.

This research addressed the role of ozone and peroxone (ozone plus hydrogen peroxide) in particle destabilization, microflocculation, and as a coagulation aid at a pilot scale water treatment facility for Colorado River Water and State Project Water. Different treatment scenarios included: (i) alum, (ii) ozone/peroxone with alum, and (iii) ozone/peroxone with ferrous sulfate. While particle destabilization was observed at all dosages of ozone and peroxone, microflocculation was observed only at lower ozone dosages and the peroxone treatments. Ozone/peroxone plus alum treatments gave improved flocculation and overall filtered water quality. Pre-oxidation with 2.5 mg/L of ozone reduces alum requirements by 50 percent. Overall, in terms of particle destabilization and microflocculation and as a coagulation aid, peroxone performed better than ozone. FeSO4 appeared to be a more effective flocculant that alum.