Landfill leachate, the liquid discharge from Municipal Solid Waste (MSW) landfills, is the combination of the surface runoff and ground water that percolates through the waste and the liquid contained in the waste itself and is considered to be toxic and presents a potential harm to the environment. Raw leachate contains high concentrations of biodegradable and non-biodegradable carbon as well as high concentrations of ammonia nitrogen. Traditionally, landfill leachate has been treated biologically through aerobic processes which reduce the biological carbon to carbon dioxide and biomass (bacterial growth) and ammonia nitrogen to nitrates. Unfortunately this is not sufficient to protect the environment from harm. It is necessary to further treat the leachate anaerobically to transform the nitrates to elemental nitrogen which is removed from the leachate as nitrogen gas. Biodegradable carbon is often the rate limiting substrate as carbon is consumed during the preceding nitrifying phase. Biodegradable carbon can be supplemented through the addition of methanol, at great expense Leachate from the Mariannhill Landfill site is currently treated aerobically in a sequencing batch reactor where nitrification is achieved. The nitrified leachate is then used as a dust suppressant on the current site. It is anticipated that in 2012 the Land fill site would have reached capacity thereby eliminating the need to irrigate and leaving the site with an excess of nitrified leachate that will present an environmental risk. The denitrifying performance of raw commercial garden refuse, pine bark and composted garden refuse as a growth medium and carbon source was investigated through the establishment of batch and column tests. CGR Raw proved the most successful of the three growth media, achieving full denitrification at a loading rate of 1700 mg NO3-N/kg of substrate/day. / Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2010.

No description available.

An extensive series of experimental tests were carried out at the Sheffield municipal solid waste incinerator plant (30 MW) from September 1988 to July 1989 to investigate the influence of the design and operating parameters on the performance of the incinerator which burns domestic and commercial wastes (500 ton/day). The following measurements were made around the plant: temperature measurements, pressure measurements, flue gas composition analysis and determination of physical and chemical properties of Sheffield refuse. Several other miscellaneous measurements were also made to monitor the effect of variation of operating parameters on the performance characteristics of the incinerator. A combustion model of Essenhigh type was then employed to model the combustion processes inside the solid refuse bed on top of the travelling grate. In addition a mathematical model of the finite difference type (FLUENT) was used to predict the three dimensional reacting flows (gaseous phase) within the incinerator geometry. Experimental measurements of gas composition, temperature and exit velocity were compared with model predictions. Modelling results were generally in good agreement with measurements. As a result of the test data and the mathematical modelling of the whole process, suggestions for design improvements for the Sheffield municipal solid waste incinerator were made which will substantially increase the efficiency, reduce emissions of pollutants and reduce the maintenance costs at the plant. These are: a) replacing the existing secondary air system with secondary air nozzles and the use of more secondary air (up to 20 % of total air) in order to generate turbulence in the high intensity combustion zone where it is most needed and b) introducing a baffle into the main stream inside the radiation shaft in order to lower the gas temperatures entering the precipitator and to remove the existing recirculation zone in the shaft.

The response of the lux-biosensors to a range of environmental pollutants was determined, as well as the stability of the biosensors to a range of environmental parameters. The biosensors were found sensitive to a range of pollutants at environmentally relevant concentrations. These included the pollutants prevailing at the contaminated site (BTEX and major co-contaminants). Analysing the bioluminescence dose-response curves to different pollutants, it was observed that the shape of the response appeared to be indicative of the nature of the contaminant present. The application of the lux-biosensors in the screening of groundwater and sediment samples from the contaminated site, showed different levels of toxicity which correlated well with chemical analysis. The sample screening produced a toxicity map of the site, facilitating the identification of hot-spot areas that could be further investigated. Samples with high levels of toxicity were serial diluted and dose-response curves determined to increasing concentrations of the toxic sample, in site uncontaminated groundwater. The shape of the dose-response curve was indicative of the nature of the main pollutant present. The toxic effect of a pollutant detected by the biosensors in spiked environmental samples (groundwater from the study site) correlated with the effect of the same pollutant on mineralisation. This allowed subsequent use of biosensor toxicity for predictive assessment of degradation potential in the presence of the pollutant tested, validating the use of the lux bioassay as a management tool for bioremediation. The bioremediation of the major contaminants (BTEX) on site can be constrained by the presence of co-contaminants or adverse environmental conditions that inhibit microbial activity. The determination of these constraints is crucial for the success of the bioremediation technologies. Using biosensor response linked to sample manipulations, it was possible to determine the contribution of broad classes of pollutants to the total toxicity of the samples.

No description available.

Three techniques are investigated in order to assess their applicability for use in landfill design, construction and monitoring. Firstly, an assessment is made of QA procedures during liner construction through the detailed evaluation of two case studies. Construction QA procedures on-site are compared to available guidelines. The research illustrates the requirement for standardised, regulated QA procedures on landfill sites in order to provide a recognised framework for construction control. The Moisture Condition Value Test (MCV) is evaluated for use as a method of monitoring the placement of compacted clay landfill liners. London Clay and Mercia Mudstone, collected from the QA case study sites, are tested in terms of their suitability as engineered clay liners. Although, London Clay is the most acceptable it is this material which exhibits the poorest results in the MCV testing. This is due to seepage from the apparatus at high moisture contents. The research highlights the problems with the interpretation of the protocol for the testing and the differences between the Scottish and English Road Research Laboratory guidelines (Green & Hawkins, 1987). Thirdly, two airborne remote sensing techniques (ATM and CASI) are appraised as methods of monitoring landfill gas, or possibly leachate migration, from two case study landfill sites in South West England. Vegetation stress can be linked to landfill gas migration (Flower et al., 1981) and this stress can be detected as a deviation from normal spectral reflectances in vegetation (Honer et a!., 1983a). Anomalies are identified on-site through remote sensing but they cannot be directly attributed to the landfills. This research emphasises the effects of contamination from other sources. It also requires the use of a simultaneous ground survey to collate data from boreholes with measurements of soil and vegetation types. Essentially, the QA case studies and the remote sensing show potential for future use and suggestions are made in this thesis for further research. The MCV technique provides a method for assessing the controlling parameters of compaction. With further development of aspects outlined in this investigation there is the potential for specified use of these techniques In landfill engineering and monitoring.

Thesis (Master of Engineering in Chemical Engineering)--Cape Peninsula University of Technology, 2017. / Pre-treatment of wastewater such as that from poultry slaughterhouses, which contains fats, oil,and grease (FOG) is necessary prior to the primary biological treatment of the wastewater to meet legislated discharge standards and to prevent environmental pollution. Physico- chemical pre-treatment is often applied to remove FOG in poultry slaughterhouse wastewater (PSW) before biological treatment. These pre-treatment methods, in particular physical pre- treatment systems, use synthetic chemicals, known to cause environmental contamination challenges, with FOG being inefficiently removed in certain instances. Biological techniques such as bio-delipidation using enzymatic catalysis for the pre-treatment of FOG-laden PSW could enhance the efficiency of the downstream biological treatment processes. This research focused on further bio-delipidation of PSW pre-treated with a dissolved air flotation system (DAF) for FOG removal using microbial lipases from bacterial strains isolated from the PSW itself. Bacterial strains (n = 2) isolated from the PSW and screened for their potential to produce lipases were found to have a higher bio-delipidation potential when compared to other isolates (n = 18). Both isolates were identified using 16s rRNA as Bacillus sp., i.e. both Bacillus cereus AB1 (BF3) and CC-1 (B3O). These isolates were used to produce lipases, whereby are sponse surface methodology (RSM) was used to optimise pH (4-8) and temperature (30-60°C) as critical production conditions. achieving an optimum lipase production was achieved, with activity of 11.25 U/mL at 60°C, a pH of8 for BF3, and 15.50U/mL at 45°C and pH of 8.8 for B3O respectively, after 72 hours of bioreactor operation. The enzymes produced from both isolates were partially purified using a Bio-Rad size exclusion chromatography column (Bio-Gel® P-60) prior to use in subsequent experiments. The presence and activity of lipase were further determined using p-nitrophenyl acetate (p- NPA) as a substrate with the functionality of the semi-purified enzymes being characterized by optimizing the conditions in which the enzymes were required to function. Lipase activity was enhanced by Mg2+ while Fe2+, Na+, K+, Ca2+ were observed to have an inhibitory effect on the enzymes from both strains. Similarly, reduced stability of the lipases in organic solvents, namely toluene, methanol, and isopropanol, was also established. Additionally, detergents, Triclosan (TCS) (5-chloro-2-(2,4-dichlorophenoxy-phenol) and trichlorocarbonilide (3,4,4- trichlorocarbonilide)(TCC), usually found in PSW as antimicrobial and disinfectant agents to sanitise poultry product processing facilities, were used assess the activity of the enzyme in their presence at a concentration of 30% (v/v) (although these anti- microbial agents are used in minute quantities in cleaning products). The lipases from isolate BF3 maintained an activity of 91.43% and 81.36% in the presence of TCS and TCC, while that of B3O enzyme had 85.32% and 73.91% acitivity, when compared to the reference (control) experiments. The bio-delipidation efficacy was studied under varying pH and temperature conditions using DAF pre-treated PSW, observing a further removal efficiency of fatty acids from the protein- laden PSW at different pH and temperature. Bio-delipidation was found to be largely influenced by pH, as a pH below 7 and above 10 at 40°-45°C, calculated in the bio- delipidation efficiency reduction to below 50%. The temperature range mentioned, i.e 40°- 45°C, had a positive effect on further deffating of the protein-rich DAF pre-treated PSW, as high removal efficiency was observed at this temperature range. This could be due to the characteristic of the enzymes used,or the formation of stable FOG agglomerates and/oremulsion. Overall, a DAF effluent containing residual FOG and proteins was bio-delipidated effectively using enzymes from the PSW isolates, achieving further removal of FOG and proteins by 64.35% to 80.42%, culminating in tCOD reduction and reduced PSW turbidity, further resulting in improved wastewater quality characteristics meeting disposal standards. This study demonstrated that sequential DAF pre-treated PSW bio-delipidation has the potential to enhance the efficiency of downstream biological anaerobic treatment processes for PSW by further reducing residual FOG from a DAF system.

Thesis (Masters of Engineering in Chemical Engineering)--Cape Peninsula University of Technology, [2018]. / Enhancing the efficiency of large scale photocatalytic systems has been a concern for decades. Engineering design and modelling for the successful application of laboratory-scale techniques to large scale is obligatory. Among the many fields of research in heterogeneous photocatalysis, photocatalytic reaction engineering can initiate improvement and application of conservative equations for the design and scale-up of photocatalytic reactors. Various reactor configurations were considered, and the geometry of choice was the annular shape. Theory supports the view that annular geometry, in the presence of constant transport flow properties, monochromatic light, and an incompressible flow, will allow a system to respect the law of conservation of mass. The degradation of a simulated dye, methyl orange (MO), by titanium dioxide (TiO2) with a simulated solar light (halogen lamp) in a continuous recirculating batch photoreactor (CRBPR) was studied. A response surface methodology (RSM) based on central composite design (CCD) was applied to study interaction terms and individual terms and the role they play in the photocatalytic degradation of MO. The studied terms were volume (L), TiO2 (g), 2 (mL), and initial dye concentration (mg/L), to optimize these parameters and to obtain their mutual interaction during a photocatalytic process, a 24 full-factorial CCD and RSM with an alpha set to 1.5 were employed. The polynomial models obtained for the chosen responses (% degradation and reaction rate constant, k) were shown to have a good externally studentized vs normal percentage probability fit with R2 values of 0.69 and 0.77 respectively. The two responses had a common significant interaction term which was the H2O2 initial dye concentration term. The optimum degradation that was obtained in this study was a volume of 20 L, TiO2 of 10 g, H2O2 of 200 mL and the initial dye concentration of 5 mg/L which yielded 64.6% and a reaction rate constant of 0.0020 min-1. The model of percentage degradation was validated on a yield of 50% and 80% over a series of set volumes and the model validation was successful.

Thesis (Master of Engineering in Chemical Engineering)--Cape Peninsula University of Technology, 2018. / Brewer’s spent grain (BSG), a solid residue obtained from brewing beer, is gaining attention in the food, cosmetics and pharmaceutical industry due to its use as natural source of colorants, texturisers, functional ingredients and preservatives. It is therefore necessary to develop an economically viable method for the extraction, isolation or enrichment of these compounds. Although literature shows the technical feasibility of extraction of bioactive compounds from BSG at laboratory bench scale, none of the reviewed literature could provide adequate information necessary to determine the economic feasibility of the process at commercial scale. The aim of this study was to investigate the technical and economic viability of a commercial process for the recovery of antioxidant rich polyphenolic compounds from brewers spent grain using organic solvents and/or water. The objectives were to select the best solvent, perform the optimisation and kinetic study, as well as to model and simulate the extraction process with the aim of performing an economic analysis. In selecting the best solvent, maceration and soxhlet extraction were used for the recovery of polyphenolic compounds. Acetone and acetone: water mixtures, ethanol and ethanol: water mixtures as well as pure water were used as solvents. The evaluation of the best solvent was measured by the total phenolic content (TPC), flavonol content, the antioxidant activity using 2.2-diphenyl-1-picrylhydrazyl (DPPH) assay and ferric reducing antioxidant power (FRAP) assay. The study performed optimisation for various operational parameters (time, temperature, solvent to feed ratio and shaking speed) using response surface method. The effect of temperature on the extraction kinetics was also investigated with experiments being carried out at 20°C, 40°C and 80°C. Antioxidant activity was detected in all BSG extracts, but water showed the highest global yield and rates of extraction. The optimum conditions were found at 15 min reaction time, temperature of 40 °C, shaking speed of 185 rpm and solvent to solid ratio of 27.5: 1. So-Macdonald model was a suitable fit for the experimental data with a R2-value range of (0.85 < r2 < 0.995). A processing scenario was proposed as a base case, upon which subsequent scenarios were generated to improve the operation or the economics. SuperPro Designer® (Intelligen, Inc) was used for modelling the proposed process, for simulation and for the economic evaluation. Four alternative schemes from the base case simulation were developed for optimisation of the process. The process was found to be economically feasible and attractive with a return of investment (ROI) of 48.45 % for alternative scheme 4. The results in this thesis highlight the likely economic feasibility of the extraction of polyphenolic compounds from BSG at commercial scale by the maceration method.

Every attempt by the NSW State Government to site waste treatment and disposal facilities has been met by opposition from local communities. Increasing interest is being shown in community consultation and public participation in the decision-making processes concerning the siting of waste management technologies. This thesis examines the rationale behind, and potential of, community consultation through an examination of two case studies. The thesis concludes that the reasons and remedies for local opposition typically given by experts and regulatory authorities are flawed. The engineering concerns which have dominated approaches to choosing and siting waste management technologies are of little consequence to the way in which communities judge whether the facilities pose an acceptable societal risk. The issues of concern to communities include the legitimacy of the decision-making process, the relative fairness of the decision to site, and whether the institutions responsible for managing and operating the technologies are trustworthy. If waste management technologies rely on local acceptability for their siting, the approach taken to resolve the waste problem must include societal as well as engineering concerns in the design of courses of action to manage the risk. / Doctor of Philosophy (PhD)