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Anaerobic digestion is a process that simultaneously treats waste and produces renewable energy in the form of biogas. Applications include swine and cattle waste management, which is still dominated by aerobic digestion, a less environmental alternative. The low adoption rates of anaerobic digestion is partly caused by the lack of modelling basis for the technology. This is due to the complexity of the process, as it involves dozens of interrelated biochemical reactions driven by hundreds of species of micro-organisms, immersed in a three-phase, non-Newtonian fluid. As a consequence, no practical computer models exist, and therefore, unlike most other engineering fields, the design process for anaerobic digesters still relies heavily on traditional methods such as trial and error. The current state-of-the-art model is Anaerobic Digestion Model No. 1 (ADM1), published by the International Water Association in 2001. ADM1 is a bulk model, therefore it does not account for the effects of concentration gradients, stagnation regions, and particle settling. To address this, this thesis works toward the creation of the first three-dimensional spatially resolved anaerobic digestion model, called Anaerobic Digestion Model with Multi-Dimensional Architecture (ADM-MDA), by developing a framework. The framework, called Coupled Reaction-Advection Flow Transient Solver (CRAFTS), is a general reaction solver for single-phase, incompressible fluid flows. It is a novel partial differential and algebraic equation (PDAE) solver that also employs a novel programmable logic controller (PLC) emulator, allowing users to define their own control logic. All aspects of the framework are verified for proper function, but still need validation against experimental results. The biochemistry from ADM1 is input into CRAFTS, resulting in a manifestation of ADM-MDA; however the numerical stiffness of ADM1 is found to conflict with the second order accuracy of CRAFTS, and the resulting model can only operate under restricted conditions. Preliminary results show spatial effects predicted by the CRAFTS model, and non-observable in the bulk model, impact the digester in a non-trivial manner and lead to measurable differences in their respective outputs. A detailed discussion of suggested work to arrive at a practical spatially resolved anaerobic digestion model is also provided.

The coconut rhinoceros beetle, an economically important pest of coconut and oil palms, is effectively managed by application of its natural pathogen, the Oryctes nudivirus (OrNV), which act as a bioinsecticide. While this approach offers an environment-friendly alternative to chemical pesticides, the current method of production in infected larvae suffers from inconsistencies in virus productivity and purity. While the anchorage-dependent DSIR-HA-1179 insect cell line has been identified as a susceptible and permissive host for OrNV and therefore would be suitable for the in vitro mass production of the virus, no attempts have been made toward the mass production of the virus, because of the technological challenges that working with DSIR-HA-1179 cells represent. Thus, the main objective of this research was to develop processes for the in vitro production of OrNV in the DSIR-HA-1179 cell line. Knowledge of the growth kinetics and metabolic properties of the host cell line in a chosen culture medium, as well as the selection of an appropriate infection strategy, form the basis for the rational development of bioreactor-based virus production processes. However, characterization of these properties in the DSIR-HA-1179 cell line has been virtually precluded, due to its strongly adherent growth characteristics and the lack of a reliable method to accurately dissociate and count cells grown in monolayers. Using TrypLE™ Express enzyme, a technique allowing the precise counting of cells was developed. The cell line was adapted to grow in four serum-supplemented culture media: TC-100, IPL-41, Sf-900 II and Sf-900 III, which were then individually screened for cell growth and virus production in 25 cm2 attached T-flask cultures. TC-100 supplemented with 10% fetal bovine serum was chosen as a suitable culture medium, based on its capacity for achieving a high cell yield and OrNV production. The cell line metabolism was characterized with respect to nutrient consumption and metabolites production in this culture medium. Glucose, along with glutamine were found to be the nutrients that were consumed faster and to a greater extent, while other amino acids were not consumed to a significant degree. The production of metabolites was characterized by non-production of lactate and ammonia, and production of alanine, as a non-toxic alternative to ammonia. The influence of cell density (CD) at time of infection (TOI) and multiplicity of infection (MOI) on OrNV production was evaluated in T-flask cultures that were infected at different CDs at the TOI and a range of MOIs. The CD at TOI was found to significantly influence OrNV yields, while MOI influenced the dynamics of infection. The cell density effect was found to exist for the DSIR-HA-1179/OrNV system with the progressive decline in cell-specific yield beginning at low cell densities. It was found that in order to maximize OrNV volumetric yield, a combination of MOI and CD at TOI should be selected that allows to keep the maximum cell density reached by the infected culture within a range between 5.0 and 7.0 x 105 viable cells/ml. The roller bottle system was evaluated for its potential to scale-up DSIR-HA-1179 cell growth and OrNV production, and culture parameters were optimized for the improvement of cell and virus yields. An inoculum density of 3.3 x 105 cells/ml and culture volume of 60 ml resulted in the highest cell yield of 1.5 x 106 cells/ml, in 490 cm2 roller bottles. It was found that an optimal infection strategy for roller bottle cultures, which represented the most efficient use of viral inoculum, involved infecting cells at a density of 5.0 x 105 cells/ml and at a MOI of 1. The resulting OrNV volumetric yield of 2.5 x108 TCID50/ml, improved significantly the viral yields obtained in attached T-flask cultures infected under similar conditions (6.8 x 107 TCID50/ml). The microcarrier system was also evaluated for culturing DSIR-HA-1179 cells and producing OrNV in spinner flask bioreactors. Three types of microcarriers (Cytodex-1, Cytodex-3 and Cultispher-G microcarriers) were screened for their ability to support DSIR-HA-1179 growth. Cells attached to Cytodex-1 and 3, but failed to attach to Cultispher-G microcarriers. The final cell density reached in microcarrier culture was dependent on bead type and concentration, and the cell to bead ratio. At an optimal bead concentration of 1 mg/ml and cell to bead ratio of 30, cells grew to a maximum density of 1.7 x 106 cells/ml on Cytodex-1, but only to 1.3 x 106 cells/ml on Cytodex-3 microcarriers. Since it supported higher cell yields, Cytodex-1 was chosen to study the kinetics of OrNV production in this system. Microcarrier cultures infected at a cell density of 5.0 x 105 cells/ml and a MOI of 1, produced OrNV at 1.4 x 108 TCID50/ml, which was higher than the yield obtained in T-flask cultures infected under similar conditions. A framework of knowledge on the physiology, metabolism and growth kinetics of the DSIR-HA-1179 insect cell line has been developed in this thesis. In addition, the feasibility of using roller bottles and microcarrier systems for the in vitro production of the virus has been ascertained. It is envisaged that these findings will contribute to the future development of a large-scale industrial process for the production of the OrNV biopesticide.

The treatment of Mn and SO42- contaminated mine drainage via a sulfate reducing bioreactor is expected to result in near-permanent immobilization of significant amounts of Mn and a portion of the sulfates within the matrix. This study tested several different combinations of organic amendments and inorganic substrates in an attempt to optimize sulfate reducing conditions and Mn removal capacity. Five different organic carbon sources, including corn mash, wood mulch, biosolids, soybean oil, and sorghum syrup in combination with five different inorganic substrates, including creek sediment, marble and limestone chips, polished gravel, and sand were tested in batch experiments. Results indicate a widely Mn variant removal potential among the treatments, ranging from 35% for soybean oil to 97% for the mulch mixture, with respective Eh ranges of +60 mV and -320 mV. Sulfate removal ranged from less than 10% to 85%. The most favorable combinations were tested in small scale bioreactors under dynamic conditions. Greater than 90% of Mn and 70% of sulfate was removed over a 65 day test period. Results indicate Mn removal mechanisms include sulfide, oxide, and carbonate formation and simple sorption and SO42- removal mechanisms of sulfide gas evolution, gypsum and MnS precipitation, and anion sorption/cation bridging.

Water infrastructure on Aboriginal communities in Canada, and specifically Northern Manitoba is in sub-standard condition. A recent Government of Canada study indicated that an estimated $1.5 billion would need to be spent to improve this infrastructure. September 2003 through July 2004, an examination of the effectiveness of a membrane bioreactor (MBR) in a Northern Manitoban Aboriginal community took place. This study was intended to identify and test an appropriate and effective solution for the lack of adequate wastewater treatment in these communities. The MBR system, employing a Zenon ZW-10 ultrafiltration membrane, was designed and constructed at the University of Manitoba. It was installed and tested in two phases at the Opaskwayak Cree Nation Reserve in Northern Manitoba. Phase I was a direct comparison between the pilot-scale MBR and the community’s existing Sequencing Batch Reactor (SBR) with sand filter. This phase occurred from September 2003 until December 2003. The MBR, with an SRT of 20-days and an HRT of 10 hours, outperformed the SBR in every category despite 2 mechanical/electrical failures that resulted in the loss of biomass from the MBR. The SBR/Sand filter combination had BOD, TSS, and TKN concentrations of 30.3 mg/L, 27.5 mg/L, and 8.4 mg/L, respectively. By comparison, the BOD, TSS, and TKN concentrations in the MBR effluent were <6 mg/L, <5 mg/L, and 1.3 mg/L respectively. Phase II, from March 2004 through July 2004, tested the overall MBR efficacy and intended to assess a novel remote control and monitoring system. The MBR SRT was adjusted to 40-days and, as expected, the MBR MLVSS concentration increased to a relatively stable 5000 mg/L. The MBR continued to provide high quality effluent with some exceptions. Despite the 0.034 μm pore size, the total coliforms and TSS measured in the effluent were higher than in Phase I. This indicates a compromised membrane, faulty sampling procedures, or biological regrowth downstream of the membrane. This failure could point to the need for some form of tertiary disinfection. Also in Phase II, a remote control and monitoring program was implemented. The controlling PC was controlled via the internet using pcAnywhere software. The software allowed for real-time monitoring and complete control of the pilot system. In conclusion, the pilot-scale MBR yielded consistent, high quality wastewater effluent and this would benefit the pristine environments existing in Manitoba’s north. The potential hands-free operation could be utilized to provide support to communities lacking sufficient wastewater treatment know-how.

Anaerobic digestion is a process that simultaneously treats waste and produces renewable energy in the form of biogas. Applications include swine and cattle waste management, which is still dominated by aerobic digestion, a less environmental alternative. The low adoption rates of anaerobic digestion is partly caused by the lack of modelling basis for the technology. This is due to the complexity of the process, as it involves dozens of interrelated biochemical reactions driven by hundreds of species of micro-organisms, immersed in a three-phase, non-Newtonian fluid. As a consequence, no practical computer models exist, and therefore, unlike most other engineering fields, the design process for anaerobic digesters still relies heavily on traditional methods such as trial and error. The current state-of-the-art model is Anaerobic Digestion Model No. 1 (ADM1), published by the International Water Association in 2001. ADM1 is a bulk model, therefore it does not account for the effects of concentration gradients, stagnation regions, and particle settling. To address this, this thesis works toward the creation of the first three-dimensional spatially resolved anaerobic digestion model, called Anaerobic Digestion Model with Multi-Dimensional Architecture (ADM-MDA), by developing a framework. The framework, called Coupled Reaction-Advection Flow Transient Solver (CRAFTS), is a general reaction solver for single-phase, incompressible fluid flows. It is a novel partial differential and algebraic equation (PDAE) solver that also employs a novel programmable logic controller (PLC) emulator, allowing users to define their own control logic. All aspects of the framework are verified for proper function, but still need validation against experimental results. The biochemistry from ADM1 is input into CRAFTS, resulting in a manifestation of ADM-MDA; however the numerical stiffness of ADM1 is found to conflict with the second order accuracy of CRAFTS, and the resulting model can only operate under restricted conditions. Preliminary results show spatial effects predicted by the CRAFTS model, and non-observable in the bulk model, impact the digester in a non-trivial manner and lead to measurable differences in their respective outputs. A detailed discussion of suggested work to arrive at a practical spatially resolved anaerobic digestion model is also provided.

Despite emerging water shortages, most water is only used once, and often with low efficiency. However, with appropriate treatment, water can be re–used to reduce the demand on freshwater sources. The Department of Water Affairs, South Africa, promotes industries to reduce discharges into water resources in order to sustain an overall good water quality of all water systems. All of this ultimately leads to industries striving towards zero effluent discharge. Primary Column Bottoms (PCBs) is a wastewater stream derived from the Fischer–Tropsch Gas to Liquid process and consists mainly of organic acids, but no nitrogen or phosphorous, which by implication excludes possible biodegradation. In the operation of cooling towers in industrial processes, cooling water quality has a direct impact on the cooling performance of the system, where nutrient levels may affect fouling, scaling and corrosion observed in the cooling towers. Fouling, scaling and corrosion affect the operating efficiency of cooling water systems and may necessitate the addition of chemical agents to control these phenomena. This has a financial and labour time impact on the operation of these systems. In this study a mini cooling tower test rig was operated with a synthetic PCB effluent as cooling water and various cycles of concentration, pH and linear flow velocities (LFVs). A constant delta temperature of 10 °C was maintained. Cycles of concentration (COC) evaluated included 2, 4 and 6 cycles of concentration and linear flow velocities evaluated was 0.6 m/s, 0.9 m/s and 1.2 m/s. Fouling, scaling and corrosion rates were determined using corrosion coupons and heat exchanger tubes for mild steel and stainless steel. Besides the evaluation of the various operational parameters for fouling, scaling and corrosion, the possibility for chemical oxygen demand (COD) removal by operating the cooling tower as a bioreactor was also evaluated. To this end nutrient correction was applied to the reactor to allow for a CNP ratio of 100:10:1. With regard to fouling, scaling and corrosion, mild steel was more affected by fouling, scaling and corrosion compared to stainless steel where almost no fouling, scaling and corrosion was observed. Overall increased linear flow velocities resulted in higher fouling and scaling rates, whereas lower linear flow velocities resulted in decreased corrosion rates. In terms of cycles of concentration, increased COC resulted in higher fouling, scaling and corrosion rates. Despite the high nutrient removal levels, the accompanying fouling, scaling and corrosion was still below the particular industry’s guidelines. Besides physical–chemical evaluation of the towers under the various operational conditions, culture–dependent and culture–independent methods were also employed. Concerning culture–dependent approaches the study demonstrated that aerobic and anaerobic organisms are present in both the planktonic and sessile phase of the cooling tower reactors. Heterotrophic aerobes were found to be the most abundant under all the operating conditions. Sulphate reducing bacteria were more abundant in the sessile phase of the cooling towers, and the presence of high sulphate levels in the experiments could be indicative of the sulphate reducing bacteria actively participating in the microbial community. Lower than expected corrosion levels, however, suggest that a combination of the organisms in the biofilm rather than sulphate reducing bacteria alone, contributed to the corrosion rates observed. Culture–independent methods, specifically phospholipid fatty acid analysis supported the results from the culture–dependent methods. Furthermore results demonstrated that linear flow velocity had a greater effect on the community structure than cycles of concentration. Finally molecular methods, specifically denaturing gradient gel electrophoresis, found that increasing cycles of concentration resulted in increased microbial community diversity, while increasing linear flow velocity resulted in decreased microbial community diversity. Regarding COD removal, nutrient correction of the synthetic PCB effluent achieved 89.35 % COD removal at 2 COC and 1.2 m/s LFV, while 80.85 % COD removal was achieved at 4 COC at 1.2 m/s LFV. From these results it was recommended that the operation of the cooling tower should be at 4 COC and 1.2 m/s, which despite slightly lower % COD removal, were characterised by fouling, scaling and corrosion rates well within guidelines. / Thesis (M. Environmental Science)--North-West University, Potchefstroom Campus, 2012.

Water infrastructure on Aboriginal communities in Canada, and specifically Northern Manitoba is in sub-standard condition. A recent Government of Canada study indicated that an estimated $1.5 billion would need to be spent to improve this infrastructure. September 2003 through July 2004, an examination of the effectiveness of a membrane bioreactor (MBR) in a Northern Manitoban Aboriginal community took place. This study was intended to identify and test an appropriate and effective solution for the lack of adequate wastewater treatment in these communities. The MBR system, employing a Zenon ZW-10 ultrafiltration membrane, was designed and constructed at the University of Manitoba. It was installed and tested in two phases at the Opaskwayak Cree Nation Reserve in Northern Manitoba. Phase I was a direct comparison between the pilot-scale MBR and the community’s existing Sequencing Batch Reactor (SBR) with sand filter. This phase occurred from September 2003 until December 2003. The MBR, with an SRT of 20-days and an HRT of 10 hours, outperformed the SBR in every category despite 2 mechanical/electrical failures that resulted in the loss of biomass from the MBR. The SBR/Sand filter combination had BOD, TSS, and TKN concentrations of 30.3 mg/L, 27.5 mg/L, and 8.4 mg/L, respectively. By comparison, the BOD, TSS, and TKN concentrations in the MBR effluent were <6 mg/L, <5 mg/L, and 1.3 mg/L respectively. Phase II, from March 2004 through July 2004, tested the overall MBR efficacy and intended to assess a novel remote control and monitoring system. The MBR SRT was adjusted to 40-days and, as expected, the MBR MLVSS concentration increased to a relatively stable 5000 mg/L. The MBR continued to provide high quality effluent with some exceptions. Despite the 0.034 μm pore size, the total coliforms and TSS measured in the effluent were higher than in Phase I. This indicates a compromised membrane, faulty sampling procedures, or biological regrowth downstream of the membrane. This failure could point to the need for some form of tertiary disinfection. Also in Phase II, a remote control and monitoring program was implemented. The controlling PC was controlled via the internet using pcAnywhere software. The software allowed for real-time monitoring and complete control of the pilot system. In conclusion, the pilot-scale MBR yielded consistent, high quality wastewater effluent and this would benefit the pristine environments existing in Manitoba’s north. The potential hands-free operation could be utilized to provide support to communities lacking sufficient wastewater treatment know-how.

Despite emerging water shortages, most water is only used once, and often with low efficiency. However, with appropriate treatment, water can be re–used to reduce the demand on freshwater sources. The Department of Water Affairs, South Africa, promotes industries to reduce discharges into water resources in order to sustain an overall good water quality of all water systems. All of this ultimately leads to industries striving towards zero effluent discharge. Primary Column Bottoms (PCBs) is a wastewater stream derived from the Fischer–Tropsch Gas to Liquid process and consists mainly of organic acids, but no nitrogen or phosphorous, which by implication excludes possible biodegradation. In the operation of cooling towers in industrial processes, cooling water quality has a direct impact on the cooling performance of the system, where nutrient levels may affect fouling, scaling and corrosion observed in the cooling towers. Fouling, scaling and corrosion affect the operating efficiency of cooling water systems and may necessitate the addition of chemical agents to control these phenomena. This has a financial and labour time impact on the operation of these systems. In this study a mini cooling tower test rig was operated with a synthetic PCB effluent as cooling water and various cycles of concentration, pH and linear flow velocities (LFVs). A constant delta temperature of 10 °C was maintained. Cycles of concentration (COC) evaluated included 2, 4 and 6 cycles of concentration and linear flow velocities evaluated was 0.6 m/s, 0.9 m/s and 1.2 m/s. Fouling, scaling and corrosion rates were determined using corrosion coupons and heat exchanger tubes for mild steel and stainless steel. Besides the evaluation of the various operational parameters for fouling, scaling and corrosion, the possibility for chemical oxygen demand (COD) removal by operating the cooling tower as a bioreactor was also evaluated. To this end nutrient correction was applied to the reactor to allow for a CNP ratio of 100:10:1. With regard to fouling, scaling and corrosion, mild steel was more affected by fouling, scaling and corrosion compared to stainless steel where almost no fouling, scaling and corrosion was observed. Overall increased linear flow velocities resulted in higher fouling and scaling rates, whereas lower linear flow velocities resulted in decreased corrosion rates. In terms of cycles of concentration, increased COC resulted in higher fouling, scaling and corrosion rates. Despite the high nutrient removal levels, the accompanying fouling, scaling and corrosion was still below the particular industry’s guidelines. Besides physical–chemical evaluation of the towers under the various operational conditions, culture–dependent and culture–independent methods were also employed. Concerning culture–dependent approaches the study demonstrated that aerobic and anaerobic organisms are present in both the planktonic and sessile phase of the cooling tower reactors. Heterotrophic aerobes were found to be the most abundant under all the operating conditions. Sulphate reducing bacteria were more abundant in the sessile phase of the cooling towers, and the presence of high sulphate levels in the experiments could be indicative of the sulphate reducing bacteria actively participating in the microbial community. Lower than expected corrosion levels, however, suggest that a combination of the organisms in the biofilm rather than sulphate reducing bacteria alone, contributed to the corrosion rates observed. Culture–independent methods, specifically phospholipid fatty acid analysis supported the results from the culture–dependent methods. Furthermore results demonstrated that linear flow velocity had a greater effect on the community structure than cycles of concentration. Finally molecular methods, specifically denaturing gradient gel electrophoresis, found that increasing cycles of concentration resulted in increased microbial community diversity, while increasing linear flow velocity resulted in decreased microbial community diversity. Regarding COD removal, nutrient correction of the synthetic PCB effluent achieved 89.35 % COD removal at 2 COC and 1.2 m/s LFV, while 80.85 % COD removal was achieved at 4 COC at 1.2 m/s LFV. From these results it was recommended that the operation of the cooling tower should be at 4 COC and 1.2 m/s, which despite slightly lower % COD removal, were characterised by fouling, scaling and corrosion rates well within guidelines. / Thesis (M. Environmental Science)--North-West University, Potchefstroom Campus, 2012.