MSc Thesis / A dissertation submitted in partial fulfilment of the requirements for the degree Master of Science in Engineering to the Faculty of Engineering and the Built Environment, School of Chemical and Metallurgical Engineering, University of the Witwatersrand, Johannesburg, 2018 / This work aims at designing and simulating on Aspen Plus process simulator a process that can recover valuable chemicals from a High Organic Waste (HOW) stream produced at Sasol Secunda plant, South Africa. The waste is made up of low boiling point organic components such as pyridine, acetonitrile and Methyl Ethyl Ketone and water. Currently, the waste is incinerated without energy recovery. This practice serves to exacerbate the already high greenhouse gases emissions from the plant, but more importantly, it results in the missed opportunity to maximize revenues through resale of recycled valuable chemicals. The recovery of valuable chemicals from the HOW is made difficult by the formations of azeotrope between organic components and water; at least 6 azeotropes exist in the HOW stream. In this work the emphasis is on pyridine because of its established market value and demand. Pyridine market size is about 400 million USD in 2017 and is expected to increase to over 600 million USD by 2021 mainly due to increased usage in the agrochemical industry. Water integration strategy was also assessed demand because of the reported need to improve water utilization efficiency at Sasol Secunda plant. The recovery was achieved in 2 separate steps: 1) water-pyridine mixture was separated from the rest of the HOW stream using fractional distillation and 2) pyridine enrichment section which was designed using thermodynamic tools such as residue curve maps and isovolatility curves. The rest of the HOW stream (light fractions) was sent to the currently used incinerator. Liquid-liquid extraction and azeotropic distillation were considered for the pyridine enrichment step. Results showed that the combination of liquid-liquid extraction and distillation offered the benefit of a lower entrainer to azeotropic mixture ratio (EA) compared to azeotropic distillation. This gave the lowest recorded EA at 0.320:1. The comparison between the proposed process and the incineration of the whole HOW stream showed that the implementation of the process proposed reduced the incineration load by 60wt% and CO and CO2 emissions by 50%. Dividing Wall column process integration technique was implemented to reduce the number of distillation columns in the proposed process and 10% reduction in the reboiler and condenser duties was observed. Implementation of DWC further improved the purity of the recovered pyridine from 96mol% to over 99.9mol%. Preliminary economic evaluation carried out on Aspen Plus showed that the proposed recovery process was profitable with an Internal Rate of Return (IRR) of 20% and a payback period of 4.5 years. / MT 2018

M. Tech. Chemical Engineering / Environmental pollution due to heavy metals is a global crisis. Contamination as a result of heavy metals from industries such as mining operations, electroplating facilities, etc. pose serious threats to the aquatic ecosystem, people and the environment. Lead (Pb), cadmium (Cd), zinc (Zn), copper (Cu), mercury (Hg) and nickel (Ni) are common examples of heavy metal ions often detected in most effluents. They are characterised by their non-biodegradability, toxicity and tendency to accumulate in living organisms, and thereafter, cause various diseases and disorders. In this study, two nano-structured composite bio-sorbents were prepared to determine their metal binding capacity, effect of solution pH, contact time and elution in a magnetically assisted adsorption system. Consequently, this study aims to develop magnetically assisted adsorption process for industrial wastewater treatment for re-use.

The study investigated solid waste management in the Mafikeng Municipality including the attitudes of the residents towards the waste management services rendered by the municipality. The study found the followings: the main sources of waste were from households due to minimal industrial activity in the area; that the residents had negative attitudes and perceptions about the waste management services provided by the Municipality. The majority of residents were not involved in the identification of needs and management of solid waste. They wanted to take an active role in the planning, design and implementation of the service especially where the formulation of policies are concerned; adequate policy mechanisms need to be adopted to enforce proper behaviour in waste disposal. The study recommends that: • the community be involved in planning, design and implementation of the service especially where the formulation of policies are concerned. • adequate policy mechanisms need to be adopted to enforce proper behaviour in waste disposal. / Thesis (MBA) North-West University, Mafikeng Campus, 2003

Thesis (MSc)--Stellenbosch University, 2005. / ENGLISH ABSTRACT: There is increasing pressure on factories and government to practise cleaner technology. The public is becoming more and more environmentally aware and external pressure from international competitors is also forcing companies to adopt environmentally sound production practices. Our natural resources and the environment need environmentally friendly practices. Waste minimisation is not only prudent practice for manufacturing industries, but is also an integral part of environmental regulations in many countries, including South Africa. This research seeks to investigate the extent and potential for industrial waste minimisation in Stellenbosch. The objectives of this thesis are, firstly to establish and evaluate the present range and extent of industrial solid waste minimisation practices; secondly to identify and evaluate potential industrial solid waste minimisation measures that could (if necessary) be instituted in future; and finally to propose a general strategy for the minimisation of industrial solid waste in Stellenbosch. The findings reflect that currently there is little waste minimisation awareness and practice in Stellenbosch. The most common method of waste minimisation currently practised by industries is recycling through the selling of recyclables. The least common method is the equipment-related change method, due to the high costs involved in adopting this method. Based on the findings, a suitable regional waste management strategy was developed and this strategy could possibly be adopted elsewhere in South Africa. Key words: waste minimisation, waste management, re-use, recycling, factory, environment, practice, participation, cleaner technology, awareness, Stellenbosch / AFRIKAANSE OPSOMMING: Daar is toenemende druk op fabrieke sowel as op die regering om skoner tegnologie te beoefen. Die publiek raak ook toenemend meer omgewingsbewus en druk vanaf die kant van internasionale mededingers forseer maatskappye om praktyke in te stel wat gunstig is ten optigte van die omgewing. Ons natuurlike hulpbronne en die omgewing benodig omgewingsvriendelike vervaardigingspraktyke. Die beperking van afvalstowwe is nie net vir die fabriekswese 'n wyse praktyk nie, maar maak ook in vele lande, met inbegrip van Suid-Afrika, 'n integrale deel uit van regulasies met betrekking tot die omgewing. Hierdie navorsingsprojek poog om die omvang en potensiaal van beperking van afvalstowwe in Stellenbosch te ondersoek. Die doelwitte van die ondersoek is eertens om ondersoek in te stel na die huidige reikwydte en omvang van praktyke om vaste industriële afvalstowwe te beperk en dit te evalueer; tweedens om potensiële industriële vaste afvalstofbeperkingsmaatreëls wat, indien nodig, in die toekoms ingestel sou kon word, te indentifiseer en te evalueer; en dan uiteindelik 'n algemene strategie vir die beperking van vaste industriële afvalstowwe in Stellenbosch voor te stel. Die bevindings in hierdie tesis bewys dat daar tans gennge bewustheid van die noodaaklikheid van afvalstofbeperking in Stellenbosch is en dat dit ewe min in die praktyk toegepas word. Die mees algemene vorm van beperking van afvalstowwe in die fabriekswese is deur middel van verkoop van herwinbare afvalstowwe. Die mins algemene vorm van beperking van afvalstowwe hou verband met die vervanging van toerusting. Die rede hiervoor het te doen met die koste verbonde aan die strategie. Vanuit hierdie bevindings is toepaslike strategie vir die bestuur van afvalstowwe op streeksvlak ontwikkel. Hierdie strategie sou moontlik ook elders in Suid-Afrika toegepas kon word. Sleutelwoorde: beperking van afvalstowwe, afvalstofbestuur, hergebruik, herwinning, fabriek, omgewing, praktyk, deelname, skoner tegnologie, bewustheid, Stellenbosch

Every time a good is produced, waste occurs as an unwanted by-product. Waste has become a real environmental issue across the world, contributing to the degradation of the environment and human health. As part of a local and international effort to lessen industrial pollution, a concept to reduce waste production at source was introduced to companies in the early 1990s. Pioneered in the Netherlands and the United Kingdom (UK), this concept has been termed 'waste minimisation'. Waste minimisation is achieved by implementing changes to business practices and processes, such as improved housekeeping (e.g. prevention of spills), and changes to equipment that is less wasteful. It is often undertaken by a group of organisations, including for example service providers, manufacturing companies and regulators that join a waste minimisation club (WMC). This provides an opportunity in which training can be received by, waste minimisation assessments made on, and information and ideas about waste reduction at source exchanged by member companies. WMCs have been used successfully in Europe to achieve waste minimisation in industry and residential communities. This study aims to contribute to the development of a sustainable WMC model in South Africa. It analyses the WMC support structures in South Africa and compares them to support structures offered in the UK. This offers a point of reference from which the impact of South African support structures on WMCs in general, and the Pietermaritzburg Waste Minimisation Club (PWMC) in particular, can be established. The PWMC consists of small and medium companies across sectors, each with less than 200 employees and with an annual turnover less than 40 million rand. The club was initiated by the Pollution Research Group of the University of KwaZulu-Natal (UKZN). It was the first of its kind in South Africa, having been facilitated on a small budget by staff and students from the UKZN. The study found that the self-help approach adopted by the PWMC was only partially successful. The PWMC was successful in terms of raising awareness of its members to waste minimisation issues. The study also found that member companies, both from the PWMC and WMCs generally, need to be shown in practical terms that 2 waste minimisation can result in financial savings before management buy-in can be attained. If more University manpower had been allocated, in the form of students for instance, to identify and orchestrate implementation of sustainable waste minimisation solutions, the PWMC member adoption rate of waste minimisation may have been raised. The small PWMC budget may have made this impossible, however. Lack of funding may also have prevented facilitators putting together a large support team, as has been done for a similar and more successful project in England. This demonstrates that self-help WMCs need an initial funding boost to be successful. This funding should be invested in gaining buy-in from company personnel rather than to drive the waste minimisation process on behalf of member companies. Driving waste minimisation on behalf of companies or 'hand-holding' leads to a passive acceptance of waste minimisation as is currently the case in South Africa, as well as 'shirking' as has been observed in the UK. Such a facilitated self-help approach can then lay the basis for WMCs, which use the support infrastructure established by their predecessors. Studies of WMCs in England and Wales based on a self-help approach showed that they achieved financial savings that are comparable to those in demonstration clubs. The promotion of such sustainable WMCs in South Africa needs to be performed by a central support agency such as the British Envirowise. Envirowise was seen to successfully promote waste minimisation among those it reached. However, it reached only a small percentage of overall industry. A successful South African agency therefore needs to promote itself effectively and nation-wide. A successful South African Envirowise organisation should also facilitate the creation of WMCs by leading a forum of industry, service providers, higher education and waste minimisation champions of proven worth, to create an action plan for WMC development for each province. Each province would then allocate funds for a waste minimisation champion who, in conjunction with the local development agency, would create a provincial action plan for the development of facilitated self-help WMCs. The local support and expertise recruited to form and manage WMCs would decrease costs and leverage income. This kind of support agency needs to be upheld by waste management legislation based on the concept of sustainable development, recognising the need for environmental protection alongside that of economic growth. To date no such legislation is in place in South Africa. It is hoped that the White Paper on Integrated Pollution and Waste Management, which endorses the principle of sustainable development alongside with the necessity to reduce waste at source, will form the basis for a successful South African WMC culture. / Thesis (M.Env.Dev.)-University of KwaZulu-Natal, Pietermaritzburg, 2005.

Submitted in complete fulfillment for the degree of Doctor of Philosophy (Biotechnology), Durban University of Technology, Durban, South Africa, 2015. / Anaerobic digestion, a proven and highly efficient biological process for treating industrial wastewater and biogas generation is an underutilized technology in South Africa. Some of the industries that have on-site anaerobic reactors tend to face problems in operating these reactors due to poor understanding of the process and implementation of the technology. This has resulted in high pollutant loads in their final effluents and low energy recovery. In this study, an on-site full–scale upflow anaerobic sludge blanket (UASB) reactor treating brewery wastewater was extensively monitored in order to evaluate the efficiency in terms of effluent quality, biogas production and microbial structure. Furthermore, developed and adopted kinetic models were used to optimize the performance of the full–scale UASB reactor using a combined Pareto differential evolution (CPMDE) algorithm. A preliminary analysis of the raw wastewater has shown that the wastewater produced from the brewery industry was high in organic matter with a total chemical oxygen demand (COD) between 1096.41 to 8926.08 mg/L. The average removal efficiency of COD from the UASB reactor after treatment was 79% with a methane (CH4) production of 60-69% at temperature ranges of 28-32˚C and hydraulic retention time (HRT) of 12 h within the optimal pH range for anaerobic bacteria (6.6 and 7.3) under various organic loading rates. However, the results also showed an increase in total suspended solids (TSS), nitrogen (N2), ammonia (NH3) and orthophosphate concentrations when comparing the influent to the effluent, which indicated the necessity for further optimization of the reactor condition in order to reduce these effluent parameters to acceptable standards and to increase CH4 production. In order to optimize the process, a thorough understanding of microbial interaction was essential. A combination of different molecular techniques viz., fluorescence in–situ hybridization (FISH), polymerase chain reaction (PCR) and quantitative real-time PCR (QPCR) were employed to understand the microbial community structure of the granular sludge samples using species specific primers and probes. The results revealed that the dominance of diverse groups of eubacteria belonging to phyla Proteobacteria, Firmicutes and Chloroflexi and an uncultured candidate division WS6 with four different orders of methanogenic Archaea viz., Methanomicrobiales, Methanococcales, Methanobacteriales and Methanosarcinales belonging to hydrogenotrophic and aceticlastic methanogens were within the reactor samples. Quantification of the 16S rDNA copies of eubacteria and methanogenic Archaea using species-specific primers further confirmed the spatial distribution of these microorganisms within the different compartments of the reactor where, the upper compartments were dominated by eubacteria and the lower compartments by methanogenic Archaea. The concentration of Archaea per nanogram of DNA was much higher (96.28%) than eubacteria (3.78%) in lower compartments, while, the eubacteria concentration increased to 98.34% in upper compartments with a decrease in Archaea quantity (1.66%). A modified kinetic methane generation model (MMGM) was developed on the basis of mass balance principles with respect to substrate (COD) degradation and the endogenous decay rate to predict CH4 production efficiency of the reactor. Furthermore, a Stover–Kincannon kinetic model was adopted with the aim of predicting the final effluent quality in terms of COD concentration and model coefficients were determined using the data collected from the full–scale reactor. Thereafter, a model-based multi-objective optimization was carried out using the CPMDE algorithm with three–objective functions namely; maximization of volumetric CH4 production rate; minimization of effluent substrate concentration and minimization of biomass washout, in order to increase the overall efficiency of the UASB reactor. Important decision variables and constraints related to the process were set for the optimization. A set of non-dominated solutions with high CH4 production rates of between 2.78 and 5.06 L CH4/g COD/day at low biomass washout concentrations were obtained at almost constant solution for the effluent COD concentration. A high COD removal efficiency (85-87%) at ~30-31˚C and 8-9 h HRT was obtained for the multi-objective optimization problem formulated. This study could significantly contribute towards optimization of a full–scale UASB reactor treating brewery wastewater for better effluent quality and biogas production. Knowledge on the activity and performance of microbial community present in the granular sludge taken from the full–scale UASB reactor would contribute significantly to future optimization strategies of the reactor. In addition, optimization using an evolutionary algorithm under different operational conditions would help to save both time and resources wasted in operating anaerobic bioreactors.

Environmental legislation is becoming more stringent as people are realising the need for conservation and a reduction of environmental degradation in order to facilitate sustainable development. To ease legislative pressures, companies need to work together in symbiotic networks, whereby co-operation between companies results in far more innovative practices than if the companies acted individually. Success in an industrial network is largely dependent on cleaner production, where industries seek to redirect from waste treatment to waste minimisation. Cleaner production has already received international recognition and waste minimisation initiatives have been used as a tool of cleaner production. Two polluting industrial sectors within South Africa, the textile and metal finishing sectors, were chosen to investigate waste minimisation concepts. One company from each sector was used as a case study. The dissertation followed company network identification, potential to participate within an industrial symbiotic network, and waste minimisation opportunities. Suppliers and buyers, up and down the product line were identified. Relationships with these partners should be advanced such that environmental concerns are at the forefront of any decision-making. In light of developing industrial networks and maintaining symbiotic relationships, the company's potential was investigated by interviewing employees of various ranks. Both companies were partially suited to participate within an industrial symbiotic network and company-specific barriers were identified, such as ineffective internal communication. The waste minimisation investigation followed a four-phase approach of planning and organisation; pre-assessment; assessment; and feasibility study. In both the companies investigated, water savings were identified as the waste minimisation focus area with potential for improvement. In total, potential water savings of over R80 000 per annum were identified. In the textile company, the weaving department and bleach house were further investigated. Cloth weaving errors were attributed to machine stops, as each stop has the potential to result in a cloth fault. In the bleach house the potential existed to reduce the number of rinse tanks. Although a modem and automated process, the plating plant in the metal finishing company was identified as having potential waste minimisation opportunities. Of particular interest was the reduction of solution carry over from the plating tanks into subsequent tanks. Extended drip times were investigated. Additional waste minimisation opportunities included repairing pipe leaks, replacing the degreasing solvent, trichloroethylene, with a less harmful cleaning agent and establishing a symbiotic relationship with the oil supplier, Castrol. Over and above the main waste minimisation opportunities highlighted, other recommendations and potential savings were identified. Each case study emphasises that simple waste minimisation initiatives, without expending capital, reduce demands on natural resource, such as water, and benefit the company financially. Successful waste minimisation leads to further cleaner production initiatives, which may then initiate better network interactions with the further potential of promoting sustainable development. / Thesis (M.Sc.Eng.)-University of Natal, Durban, 2002.

Department of Ecology and Resource Management / MENVM

MESMEG / Department of Mining and Environmental Geology / The increase in the demand and market price of gold has led to reprocessing of gold tailings in many parts of the world. Mines are recently closing down due to depletion of resources and increasing mining costs leading to the reprocessing of old tailings dams. The cost of rehabilitation is high, and therefore a more convenient way of rehabilitation is required. The most convenient strategy identified here was to reprocess tailings for gold and use waste rocks as construction materials. The tailings residues (waste remaining after reprocessing) will be relocated to a more convenient place to avoid pollution. Gold reprocessing from tailings dams has gained momentum in South Africa especially in the Witwatersrand Basin where there are large volumes of tailings. Gold is being reprocessed from tailings in this area using hydraulic monitors. This study focused on the evaluation of gold and heavy metals within the tailings at Consolidated Murchison Mine tailings in Gravelotte, Limpopo province. Augering was conducted over the tailings up to a depth of 8 m along four sampling Profiles. The first profile had two sampling points, the second profile with three sampling points, the third and fourth profiles consisted of four and five sampling points respectively. Samples were collected at 1 m interval, therefore a total of 112 samples were collected and analysed for heavy metals using X-Ray Fluorescence spectrometry and 84 samples were analysed for gold using fire assaying. Tailings sampling was accompanied with tailings logging, taking note of colour, texture and moisture content. Based on this, the oxidation status of the tailings dam was determined. Oxidation zone of this tailings dam was mainly from top down to a depth of 3 m. The transitional zone was not identified, hence after the oxidation zone, the rest was unoxidized zone. This study established that gold was erratically distributed within the tailings dam with the lowest and highest values of 200 mg/kg and 1880 mg/kg respectively and the average was 670 mg/kg. The tonnage of tailings within the dam was found to be 13 280 310 tons with a total gold amount of 8 897. 81 kg. At the current world market, this interprets to US$ 306 932 396.00 (R 4 281 706 924.20). It was concluded that this tailings dam is economically viable for reprocessing, although previous studies have indicated that it is not possible to extract gold from tailings dams completely. The heavy metal content of Pb, Ni and Cr were found to be high with average values of (ppm); 5631.5, 2062.6 and 1345 v respectively. The metals with the lowest values were Cd, Co and Cu, averaging (ppm); 0.01 ppm, 19.8 ppm and 42.1 ppm respectively. Heavy metal content in soil around the tailings dam was gradually decreasing with distance from the tailings dam. Waste rocks have been used in some parts of the world as sub-base material for engineering construction, hence in this study, a total of 6 waste rock samples were collected using grab sampling method for geostatistical investigation. Such samples were subjected to various geotechnical tests which included particle size distribution analysis (sieve analysis), Atterberg limit tests and laboratory compaction test to determine their suitability for construction. The waste rock material was found to be suitable for road construction as it was classified under Group A-1-a using the AASHTO classification system. The material consisted mainly of rock fragments, gravel and sand material with minor silt/clay. In general, Consolidated Murchison mine waste was found to be suitable for road construction. / NRF

Industrial effluents with high concentrations of heavy metals are widespread pollutants of great concerns as they are known to be persistent and non-degradable. Continuous monitoring and treatment of the effluents become pertinent because of their impacts on wastewater treatment plants. The aim of this study is to determine the correlation between heavy metal pollution in water and the location of industries in order to ascertain the effectiveness of the municipal waste water treatment plant. Heavy metal identification and physico-chemical analysis were done using Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) and multi-parameter probe respectively. Correlation coefficients of the measured values were done to investigate the effect of the industrial effluents on the treatment plants. Heavy metal resistant bacteria were identified and characterised by polymerase chain reaction and sequencing. Leeuwkuil wastewater treatment plants were effective in maintaining temperature, pH, and chemical oxygen demand within South Africa green drop and SAGG Standards whereas the purification plant was effective in maintaining the values of Cu, Zn, Al, temperature, BOD, COD, and TDS within the SANS and WHO standard for potable water. This findings indicated the need for the treatment plants to be reviewed.The industrial wastewater were identified as a point source of heavy metal pollution that influenced Leeuwkuil wastewater treatment plants and the purification plants in Vaal, Vereenining South Africa. Pseudomonas aeruginosa, Serratia marcescens, Bacillus sp. strain and Bacillus toyonensis that showed 100% similarity were found to be resistant to Al, Cu, Pb and Zn. These identified bacteria can be considered for further study in bioremediation. / Environmental Sciences / M. Sc. (Environmental Science)