The purpose of this practicum is to design a landscape with the ability to purify wastewater from Winnipeg North End Water Pollution Control Centre and to use the purified water for the irrigation of community gardens. Water pollution has been a big issue around the world. Eutrophication refers to the overabundance of nutrients in waterbodies. Lake Winnipeg, in the province of Manitoba, one of the largest freshwater resources in Canada, has a serious eutrophication problem. One of the major nutrient loading sources is the nutrient-rich inflow from the Red River (Water Stewardship Division, n.d.), which consists of agricultural runoff and municipal and industrial wastewater. In the City of Winnipeg, the North End Water Pollution Control Centre releases a large amount of treated wastewater into the Red River. The treated wastewater is rich of phosphorus, nitrogen, and pathogen. The landscape can play a potential role to purify the nutrient-rich wastewater before it reaches the river while providing outdoor spaces for community gardens and leisurely uses. / October 2016

Treating elevated nutrients, suspended solids, oxygen demanding materials, heavy metals and chemical fertilizers and pesticides in agricultural wastewaters is necessary to protect surface and ground waters. Constructed wetlands (CWs) are an increasingly important technology to remediate wastewaters and reduce negative impacts on water quality in agricultural settings. Treatment of high strength effluents typical of agricultural operations results in the production of methane (CH4), a potent greenhouse trace gas. The objective of this study was to evaluate CH4 emissions from two subsurface flow (SSF) CWs (223 m2 each) treating dairy wastewater. The CWs were implemented at the University of Vermont Paul Miller Dairy Farm in 2003 as an alternative nutrient management approach for treating mixed dairy farm effluent (barnyard runoff and milk parlor waste) in a cold, northern climate. In 2006, static collars were installed throughout the inlet, mid and outlet zones of two CWs (aerated (CW1) and a non-aerated (CW2)) connected in-series, and gas samples were collected via non-steady state chambers (19.75 L) over a nine-month period (Feb-Oct 2007). Methane flux densities were variable throughout the nine-month study period, ranging from 0.026 to 339 and 0.008 to 165 mg m-2 h-1 in CW1 and CW2, respectively. The average daily CH4 flux of CW1 and CW2 were 1475 and 552 mg m-2 d-1, respectively. Average CH4 flux of CW1 was nearly threefold greater than that of CW2 (p = .0387) across all three seasons. The in-series design may have confounded differences in CH4 flux between CWs by limiting differences in dissolved oxygen and by accentuating differences in carbon loading. Methane flux densities revealed strong spatial and seasonal variation within CWs. Emissions generally decreased from inlet to outlet in both CWs. Average CW1 CH4 flux of the inlet zone was nearly threefold greater than mid zone and over tenfold greater than flux at the outlet, while fluxes for CW2 zones were not statistically different. Methane flux of CW1 was nearly fifteen fold greater than CW2 during the fall, representing the only season during which flux was statistically different (p = .0082) between CWs. Fluxes differed significantly between seasons for both CW1 (p = .0034) and CW2 (p = .0002). CH4 emissions were greatest during the spring season in both CWs, attributed to a consistently high water table observed during this season. Vegetation was excluded from chambers during GHG monitoring, and considering that the presence of vascular plants is an important factor influencing CH4 flux, the potential CH4 emissions reported in our study could be greatly underestimated. However, our reported average CH4 fluxes are comparable to published data from SSF dairy treatment CWs. We estimate average and maximum daily emissions from the entire CW system (892 m2) at approximately 1.11 and 6.33 kg CH4 d-1, respectively, yielding an annual average and maximum flux of 8.51 and 48.5 MtCO2-e y-1, respectively.

This thesis investigates the potential of improved control to reduce greenhouse gas (GHG) emissions resulting from existing wastewater treatment plants (WWTPs), and demonstrates that significant reductions can be achieved without the need for extensive redesign of treatment processes and without increasing operational costs. An emissions model is developed for use in this study, informed by an in-depth analysis of existing state-of-the-art methods and models for estimating GHG emissions, taking into account their suitability for dynamic modelling and WWTP control strategy optimisation. Through the use of local and global sensitivity analysis tools, sources of uncertainty in the modelling of GHG emissions from wastewater treatment are investigated, revealing critical parameters and parameter interactions; these interaction effects have not been considered in previous studies and thus provide a better understanding of WWTP model characterisation. A key finding is that uncertainty in modelled nitrous oxide (N2O) emissions is the primary contributor to uncertainty in total GHG emissions, due largely to the interaction effects of nitrogen conversion modelling parameters. Further local and global sensitivity analysis is used to investigate the effects of adjusting control handle values on GHG emissions, revealing critical control handles and sensitive emission sources for control. This knowledge assists with the following control strategy development and aids an efficient design and optimisation process. Sources with the greatest variance in emissions, and therefore the greatest need to monitor, are also identified. It is found that variance in total emissions is predominantly due to changes in direct N2O emissions and selection of suitable values for wastage flow rate and aeration intensity in the final activated sludge reactor is of key importance. Sets of Pareto optimal operational and control parameter values are derived using a multi-objective genetic algorithm, NSGA-II, with objectives including minimisation of GHG emissions, operational costs and effluent pollutant concentrations, subject to legislative compliance. It is found that multi-objective optimisation can facilitate a significant reduction in GHG emissions without the need for plant redesign or modification of the control strategy layout, but there are trade-offs to consider: most importantly, if operational costs are not to be increased, reduction of GHG emissions is likely to incur an increase in effluent ammonia and total nitrogen concentrations. Alternative control strategies are also investigated and it is concluded that independent control of dissolved oxygen in each aerated activated sludge reactor is beneficial. Optimised solutions are also assessed with respect to their reliability, robustness and resilience, taking into account the effects of influent perturbations and sensor failures on effluent quality and GHG emissions. This reveals that solutions predicted to achieve the most significant reductions in GHG emissions and operational costs under existing design conditions may perform poorly in reality when subject to threats. Dissolved oxygen setpoints which correspond with unacceptable effluent quality reliability and decision variables which should not be considered in future optimisation due to their negative impacts on reliability, robustness and resilience are also identified. Lastly, guidelines for the development of control strategies to reduce GHG emissions are presented. These address GHG emission sources, key control handles and decision variables, choice of control strategy, optimisation and detailed design, and model limitations and uncertainties.

Implementation of combined anaerobic/aerobic processes for wastewater treatment has been shown feasible, especially for industrial wastewaters with high concentration of organics. However, the utilization of this type of technology for treating wastewaters with low content of organic matter, such as domestic sewage is quite recent, and very limited information is available regarding the topic. Recent investigations have demonstrated that it is feasible to utilize a combined technology composed of anaerobic pretreatment followed by an aerobic post-treatment to efficiently treat municipal wastewater. This research is a continuation of previous investigations about the feasibility of using an anaerobic fluidized bed reactor-aerated solids contact process to treat domestic wastewater. In the proposed system the excess sludge produced in the aerobic stage is recycled to the anaerobic unit. The proposed configuration is very attractive because the anaerobic fluidized bed reactor serves as pretreatment unit and a sludge digester at the same time. The main objective of this research is to quantify the SS removal and accumulation rates in the AFBR, and determine the degree of stabilization of solids in the unit. All this to demonstrate the feasibility of avoiding separate sludge stabilization units.

There is a need to develop a mathematical expression capable of describing the removal of particulate chemical oxygen demand (PCOD) from wastewaters in biological film systems. In this context, organic particles that are maintained in suspension (i.e., not removed during normal settling) are the focus of experimentation, modeling, and discussion. The goal of this research project is to study the kinetics of PCOD removal from wastewaters by bacterial films, or biofilms. To achieve this objective, a bench-scale rotating disc biofilm reactor (RDBR) was operated using methanol (dissolved substrate), Min-U-Sil 10 (inorganic particulates), and Maizena corn starch (organic particulates) dissolved/suspended in the influent stream. The effect of the ratio of biofilm area to volumetric flow rate passing through the RDBR on the concentration of substrate remaining in the final effluent was determined, and the kinetic relationship was established for both dissolved substrate and particle removal. Exocellular polymeric substances (EPS) were extracted and quantified in order to explain the role of biological flocculation, or bioflocculation, in particulate removal. In the literature, Fick's first law and zero-order kinetics have described the diffusion and biochemical reaction of soluble substrate within the bacterial film matrix (when completely penetrated), respectively. The present study confirms this kinetic behavior for various influent methanol concentrations. On the other hand, the removal of particulates, organic and inorganic, adheres to first-order reaction kinetics. These findings, coupled with the identification of EPS, attribute bioflocculation as the primary removal mechanism of particulates. A mass balance on the biofilm reactor allowed for the development of a comprehensive rate expression for substrate consumption by biofilms when both dissolved and particulate substrates are available. Total chemical oxygen demand (TCOD) is comprised of dissolved chemical oxygen demand (DCOD) and PCOD, each of which can be readily determined through laboratory analysis. An equation was developed that accurately describes the disappearance of TCOD by the bioflocculation of PCOD and consumption of DCOD in the bench scale RDBR.

This research evaluated and demonstrated the disinfection efficiency of an electrochemical system for total coliform removal from wastewater effluents after secondary treatment. Four bench scale batch electrochemical cells were assembled and operated in the laboratory: the first electro-disinfection reactor was set with aluminum electrodes, the second with standard 316 stainless steel electrodes, the third one with titanium electrodes, and the fourth one with a standard 316 stainless steel cathode and a titanium anode. During the electro-disinfection process the water sample was placed on the reactor/disinfector to which direct current (DC) was charged. The results showed that total coliform counts in the treated water decreased significantly and that the characteristics of the effluent were highly improved, especially when stainless steel or titanium electrodes were employed. A bactericidal efficiency of 98.7 % or higher was achieved within a contact time of less than 15 min and a current density lower than 7.5 mA/cm2 when stainless steel electrodes were used, and a contact time of less than 5 min and a current density lower than 3.5 mA/cm2 when the stainless steel/titanium cell was utilized. Electrochlorination does not seem to be the predominant disinfective means of the process. Production of other short lived and more powerful killing substances such as H2O2, [O], •OH, and •HO2 provide the strong disinfecting action of the system within a short contact time. The bactericidal efficiency of the process generally increased with the current density and contact time, and the impact of these factors was much larger than that of salinity. The results obtained suggest that this electrochemical treatment is applicable to wastewater effluents. However, further investigation on the optimum operating conditions and a detailed comparative study of energy consumption by the electrochemical treatment system and the conventional methods are needed before constructing an industrial application system in the future. It is also indispensable to find out if halogenated hydrocarbons and other toxic compounds are produced during the process.

Disinfection is the final and very important step of wastewater treatment to maintain healthy ecosystems. Although chlorination is the most prevalent wastewater disinfection method, there are serious safety concerns and ecological problems associated with its use. The purpose of this study was to test the feasibility of using a HydroFLOW 60i unit for wastewater disinfection, as an alternative to chlorination. The study was performed using two different reactors, namely, a bench-scale laboratory batch reactor, and a continuous flow, pilot unit. Using the batch reactor, it was found out that the HydroFLOW 60i unit is effective to kill bacteria; however, modifications to this mode of operation would be required in order to increase the disinfection efficiency and to decrease the detention time. When the continuous flow system was run using a hydraulic detention time of 10 minutes and a single pass through the HydroFLOW unit, the E. coli removal efficiency was negligible. Further research is needed to determine the most economical and efficient reactor configuration in order to make the HydroFLOW unit competitive with conventional wastewater chlorination.

Finding the most cost-effective and environmental friendly way to treat and disinfect wastewater has been raising concerns around the world. Failure in performing disinfection of wastewater before returning it to the environment could have terrible consequences to human health and the ecosystem. The risks associated to continue with current practices have led to the creation of stringent regulations. In this research the HYDROPATH technology is tested while attaching a HydroFlow 60i unit to a reactor that works as a closed recirculation system. To determine the feasibility of the HydroFlow 60i unit as an alternative method to chlorine, the EPA method 1306 is used being Escherichia coli the unit of quantification. After performing several experiments modifying parameters such as conductivity and detention time, it was concluded that the HydroFlow 60i unit by itself would not able to replace current disinfection technologies, to meet EPA standards of E. coli removal.

Master of Science in Engineering - Engineering / Wastewater is generated in the production of water-based paints when vessels and filling lines are washed in between batches. This results in a dilute paint wastewater stream. This dissertation concerns the study of the treatment of wastewater, using flocculation and coagulation processes. Standard jar test were used in screening the flocculants. The inorganic flocculants used were ferric chloride (FeCl3) and aluminium sulphate (Al2(SO4)3) A thermodynamic model is developed for understanding the coagulation and flocculation process for inorganic flocculants. Properties such as the effect of bulk concentration, pH and feed concentration of flocculant on wastewater were investigated. The impact of kinetics and other properties such as the influence of redox potential on flocculation experiments are also evaluated in order to have an understanding of the properties that influence the flocculation of wastewater. It was found that thermodynamics could be used to predict gross flocculation behaviour. However mixing and the rate of the nucleation and growth of flocs are also important and need to be controlled for efficient and reproducible flocculation.

University of Technology, Sydney. / Wastewater contains a matrix of organic and inorganic substances both in dissolved form and in suspension. Most of the biodegradable substances are removed in primary and secondary treatment processes. However, the conventional wastewater treatment processes cannot remove a number of synthetic and refractive organic substances. These substances can cause tremendous problem in the sewage treatment processes and in the water body where the effluent from the sewage plant is discharged. These substances produce odour, colour, and require a large quantity of disinfectant dose before the wastewater can be discharged into a water body. They can also significantly deplete the dissolved oxygen level of the water receiving body thus putting all the aquatic life in danger. The effluent from the sewage treatment plant therefore, needs to be passed through further treatment process, which is called advanced sewage treatment process. The advanced treatment processes consist of many treatment options. Depending upon the characteristics of the sewage and the level of treatment required, one has to select an appropriate treatment technology. Physico-chemical processes such as coagulation-flocculation and filtration, adsorption, and membrane application are some of the most viable treatment processes that can remove the organic substances to the desirable level. In this study, adsorption, biosorption or biofiltration, and adsorption-membrane hybrid systems were investigated for the removal of organics (in terms of total organic carbon (TOC)) from a low strength synthetic wastewater and a biologically treated secondary effluent from a sewage treatment plant, Sydney. Adsorption experiments were conducted on low strength synthetic wastewater and the biologically treated sewage effluent using granular activated carbon (GAC) and powder activated carbon (PAC). The synthetic wastewater was prepared using three organic substances (glucose, peptone and yeast extract) and seven inorganic chemicals (MnS04, CaCI2, NaHC03, NaCl, MgS04·7H20, KH2P04 , and NH2·NH2·H2S04). The biologically treated sewage effluent was collected from the St. Marys sewage treatment plant, Sydney. Detailed experimental studies on adsorption equilibrium, batch kinetics and fixed bed were carried out, and the experimental results were predicted using suitable mathematical models. The adsorption equilibrium was analysed with different initial organic concentration of the synthetic wastewater. The experimental results were then predicted using association theory (AT), characterization theory (CT), and the Freundlich isotherm. The experimental results showed unfavourable type of isotherm curve, and hence, the normal favourable isotherm equations such as Langmuir, Freundlich or Sipps isotherms were not very successful in describing the adsorption equilibrium results. The AT and the CT were better in predicting the adsorption equilibrium results than the commonly used Freundlich isotherm. In this process, the adsorption equilibrium (isotherm) parameters were determined using a multi variable, non-linear regression, Nelder-Mead method by optimising an object function defined as the mean percent deviation between experimental and calculated equilibrium adsorption amounts. The isotherm parameters were found to be dependent on the initial organic concentration. Hence, it is important to estimate the isotherm parameters covering a wide range of organIc concentration. Further, the adsorption equilibrium studies of the individual organic compounds indicated that the overall effects of the inorganic substances were unfavourable for the adsorption of organics in the wastewater. The organics of the synthetic wastewater were found to undergo biodegradation after 8 hours. Thus, the effect of the background substances in the wastewater, and the biodegradation effect are another important aspects that need to be considered while evaluating the effectiveness of the adsorption process for organic removal from the wastewater. It is equally important to study the adsorption behaviour with time (i.e. adsorption kinetics). Adsorption kinetics of the organics in the wastewater was determined using linear driving force approximation (LDFA) model. Basically, the LDFA is a simplified expression of intraparticle diffusion of adsorbate into adsorbent particles. In this model, it is assumed that the uptake rate of adsorbate by an adsorbent particle is linearly proportional to the driving force developed due to the difference between the surface concentration and the average adsorbed phase concentration of the adsorbate. The main reason for using the LDFA method was the use of index (or lumped) parameter, total organic carbon (TOC), to express the total organic contents of the wastewater. The film mass transfer coefficient (kf) was found to be dependent on the experimental conditions such as mixing intensity, the adsorbent dose and the initial organic concentrations. The film mass transfer coefficient (kf) to the adsorbent increased when the mixing intensity and the adsorbent dose were increased. However, the kf value decreased with the increase in the initial organic concentration of the solution. The adsorption isotherm parameters obtained from the association theory (AT) and the characterization theory (CT), were utilized to fit the experimental results using LDFA model. The isotherm parameters obtained from both the theories were found equally effective in predicting the experimental results. The overall effect of the dissolved inorganic compounds in the synthetic wastewater solution was observed to enhance the mass transfer rate to the GAC particle. The average value of the overall mass transfer rate was in the order of 10-6 mls. The application of adsorption system in practice is usually carried out in the fixed bed adsorption mode. The adsorbent (usually GAC) is packed in a column and the target pollutants are passed through either end to be adsorbed by the adsorbent. In this study, the fixed bed adsorption study was carried out in acrylic columns in the laboratory. The GAC bed depth, organic concentration of the feed solution, and the filtration velocity through the GAC bed were varied to evaluate the effectiveness of the fixed bed adsorption system. The experiments were carried out with both the biologically treated sewage effluent and the synthetic wastewater. The experimental results were predicted using the dynamic adsorption model. The film mass transfer coefficient (kf) was obtained by fitting the fixed bed experimental data. The kf increased when filtration rate was increased, but it decreased with the increase in the organic concentration of the feed solution. As expected, the value of kf remained constant with the increase in GAC bed depth. The effect of axial dispersion coefficient was negligible, as the GAC bed depth and the size of the GAC particles used in this study were shallow and small respectively. The average value of the overall mass transfer rate in the fixed bed study was also in the order of 10-6 mls but slightly less than that obtained in batch kinetics study. The fixed bed system with attached microorganisms on the surface of the adsorbent (fixed bed medium) is referred to as a biofilter, where the organics are adsorbed (biosorption) and biodegraded by the microorganisms. The fixed bed adsorption experimentations were conducted for a longer duration to investigate the biological activity on the granular activated carbon (GAC). The experimental results showed the growth of microorganisms on the surface of GAC particles. In other words, the adsorption system turned into biosorption or biofiltration system after few weeks of operation. The adsorption capacity of the GAC particles slowly exhausted with the growth of microorganisms with time. The overall organic removal efficiency of the system was however, not impaired by the growth of microorganisms. The organics were removed by the processes of biosorption and subsequent biodegradation. The biomass growth rate was found to fluctuate with time in pattern. Despite the fluctuation in the biomass, the TOC removal efficiency of the biofiltration system was consistent at 55 % for 77 days of continuous operation. Moreover, the daily backwashing provided at 30 % bed expansion to avoid filter clogging did not have adverse effect on the TOC removal efficiency of the biofilter. The organic removal efficiency of the biofilter changed when the filtration rate was altered from that in which the biofilter was acclimatized~ however the organic removal pattern remained consistent with time. This result suggests that the biofilter should be operated in the same filtration velocity at which it is acclimatized to attain maximum efficiency of the filter. A practical mathematical model was developed incorporating both adsorption and biodegradation of organics. The organic removal efficiency of the biofilter was successfully predicted using kinetics data obtained from the previous studies. The model was sensitive to the biofilm thickness and decay constant. The adsorption-membrane hybrid system is emerging as a cost-effective membrane process for the organic removal. In this system, the organics are adsorbed on the adsorbent and the organic laden adsorbents are removed by the membrane separation process. In this study, the adsorption-membrane hybrid system was evaluated using submerged hollow fibre (pore size 0.1 ~m), and the external loop crossflow rnicrofiItration. Powdered activated carbon (PAC) was used to reduce the direct organic loading onto the membrane surface. The main function of membrane in these studies was to remove the organic laden PAC particles. The submerged PAC-Membrane hybrid system was found effective in removing dissolved organic substances both from the synthetic wastewater and the biologically treated effluent of a sewage treatment plant. The system has potential for its long-term application in the treatment of wastewater without the need of frequent membrane cleaning. This preliminary study showed that the PAC-membrane hybrid system could be used for a long time effectively (over 47 days). At the initial stage of operation, the organic removal was mainly due to adsorption by PAC, but during the long-term application of the system, the adsorption capacity of the PAC was exhausted gradually, and the microbial communities developed on the PAC, in the suspension of the reactor, and on the membrane surface actively participated in the biodegradation of the organics. An empirical mathematical model was developed for the submerged hollow fibre membrane hybrid system. The model predicted the organic removal efficiency of the system satisfactorily. A new term, membrane correlation coefficient (MCC) was introduced in the model to account for the adsorption of organics onto membrane surface. The MCC and the filtration rate (flux) were found to be the main model parameters that controlled the quality of the effluent from the system. Greater the value of MCC, better was the organic removal efficiency of the system. The MCC value was found to increase with the increase in the PAC dose to the system. Since only the short-term experiments were conducted in this study, the biological degradation of the organics was not included in the model. It is necessary to incorporate the biological degradation part in the model to predict the long-term efficiency of the system. The external loop cross-flow microfiltration system with prior PAC addition was also tested using the synthetic wastewater. This study showed that the use of PAC helped not only in the organic removal but also in the enhancement of the filtration flux. The use of PAC was instrumental in increasing the operational life the membrane hybrid system by reducing the organic fouling on the membrane. The conventional pressure filtration models, cake filtration model (CFM) and standard blocking model (SBM) were used to successfully predict the experimental results. Since CFM was more effective in predicting the volume of the permeate flux from the hybrid system, one could infer that the fouling mechanism of the membrane was mainly due to the formation of cake layer on the membrane surface. However, the experimental conditions used in the hybrid system were not so favourable for removing the organics from the synthetic wastewater. The organic removal efficiency of the PAC-membrane hybrid system was only 250/0 for the PAC dose of 150 mg/L. The organic removal efficiency of the system depends mainly on the characteristics of the adsorbent and the influent wastewater solution, and the adsorbent dose. This study shows that activated carbon can effectively be used in different operational modes and in different treatment processes to remove organics from the wastewater, and to produce effluent of high quality that can be reused for many purposes.