Two coal utility plants in South Africa selected (one from Sasol and another from Eskom) for this study produce large volumes of fly ash (over 40 Mt from Eskom at Tutuka, and 3 Mt from Sasol Synfuels at Secunda annually), and brines as by-products during coal processing. Co-disposal of the brines and fly ashes has been a normal practice in these coal-utility plants for decades. Long-term management of fly ash is necessary and requires an understanding and knowledge of how the different waste materials interact with water and brines in different chemical situations. However the geochemistry of their interactions, the leaching and mobility of elements in these disposal systems has not been fully understood. This work gives insights into the chemical processes taking place in the brine-water/brines systems that govern the concentrations of major and minor elements in ash leachates under different environmental conditions. The possible presence of organic compounds (subsequently referred to as 'organics') in brines and their effects on the leaching chemistry of fly ash was also studied. Sustainability and long term impact of the co-disposal of fly ash and brines on the environment was studied through static (batch tests) modeling of the pH-dependent acid neutralization capacity (ANC) tests and columns modeling for dynamic leach tests. The modeling was based on experimental results from other Sasol-Eskom ashbrine project collaborators. Modeling results of the ANC tests were in good agreement with the reported experimental results, which revealed that the release trends of various elements (including trace, heavy elements and contaminants) contained in fly ash into solution is highly pH dependent. However Na, K, Mo and Li exhibited constant solubilisation which was independent of pH changes from all the scenarios. The presence of different constituents of brines subjected to ANC resulted to different ANC capacities ranging from 0.98 moles H⁺/Kg dry ash (of ash-organics mixed with Mg-brines) to 3.87 H⁺/Kg dry ash for those with the C(4) brines. As expected, those constituents from the cationic brines were found on the lower region of acid addition (in the order Mg-brines < Ca-brines < Na-brines) while the anionic brines were found at the upper region of acid addition (in the order S(6)-brines < Cl-brines < C(4)-brines). In the middle region of acid addition were three important scenarios: that of ash with brine, ash without brines (i.e. ash with DMW) and ash with both ASW organics and combined brines. It was from these three scenarios that a generalization of the effect of brines and organics on the ANC was inferred. The ANC of ash with demineralised water (DMW) was 2.33 mol H⁺/Kg dry ash and that of ash with ASW organics lower at 2.12 mol H⁺/Kg dry ash which was the same value as that of ash with combined brines. This indicated that brines decreased the ANC of ash by about 9.01 % and which could be attributed to the acid-base neutralization process and the dynamics of solid phase dissolutions in response to the acid addition. Both fly ashes exhibited a typical pH > 12 (suspension in demineralised water) and the predominant cation even at this high pH is Ca²⁺ (at concentration > 0.002 mmol/L). This indicates that dissolution of CaO and formation of OH⁻ species at pH > 10 contributes to acid neutralisation capacity of both fly ashes and is the greatest contributor to the acid neutralizing capacity of both fly ashes. Two broad leaching behaviours as a function of pH were observed from the three fly ash-ASW organics-brines scenarios (i) leaching of Ca, Mg, Ni and Sr follows a cationic pattern where the concentration decreases monotonically as pH increases; (ii) leaching of Al, Fe, Ti and Zn follow an amphoteric pattern where the concentration increases at acidic and alkaline pH, although Al showed some anomaly from pH 11 where the concentration decreased with the increase in pH. Al showed an amphoteric pattern in which its release increased between pH 12.8 and 11 for all the scenarios and then decreased with decrease in pH down to neutral pH of 7. The batch leaching simulation results from hydrogeochemical modeling also showed that mineral dissolution, precipitation and new phase formation during ash-organics-brines interactions was controlled by pH. The newly formed phases however remain in equilibrium with the ash-brines-organics mixture. Each individual mineral phase dissolution/precipitation/formation system controls the concentration and speciation of the respective constituent elements as evidenced by the log C-pH diagrams obtained from the modeled scenarios. The ash-brines-organics interactions do exhibit and affect the mineralogical chemistry of fly ash. However the extent to which these interactions occur and their effect, varies from one scenario to another, and are dependent on the amounts and type of the constituent brine components. Organics do have a significant effect on dissolution characteristics of few minerals such as calcite, mullite, kaolinite, Ni₂SiO₄, and SrSiO₃ due to complexation effect. The effect is quantitatively conspicuous for calcite mineral phase and for the formation of some new phases such as Fe(OH)₃(am)-CF and portlandite. The composition of the liquid phase from acid neutralisation capacity experiments was successful.Hydrogeochemical modeling was used as a means to provide insights and understanding of the complex reactions taking place, speciation and mineralogical changes occurring. These changes would serve to predict future environmental scenarios when pH conditions change. In this study, an extension of the application field of PHREEQC hydrogeochemical code for modeling and simulation of equilibrium; kinetic and transport mechanisms associated with the interaction of water; and organics and brines with fly ash during their co-disposal is successfully demonstrated. The parameters associated with these mechanisms were used as inputs into the PHREEQC program using modified Lawrence Livermore National Laboratory (LLNL) database for inorganic brines and MINTEQ.V4 database for organics, and used to model the results of ANC test data for the fly ashes. A special reference is made to two separate modeled mineralogical ash recipes from two of the South African power utility plants' fly ash systems, namely, Tutuka and Secunda. The effects of brines in the leaching of major, minor and trace elements at various pH values and the mineralogical changes associated with the intermediate and final products from the interactions of ash-brines systems under different scenarios are qualitatively and quantatively discussed. Multiphase saturation characteristics have been determined for mineral species in contact with water and brines. The modeling results indicated that several mineral phases could be controlling the species concentration in the leachates, and the ANC and column modeling results corroborated well in many aspects with the experimental results obtained from collaborating institutions (South Africa Universities and Research institutions). In addition, application of the PHREEQC model to the ash heap under different disposal systems was carried out to predict the heap leachate composition and geochemical transformations taking place in a period of time. Pore water chemical analysis, and moisture content analysis revealed that contact of the ash with water is a crucial factor in the mobilization of the contaminants with time. Maximum weathering/dissolution of the ash is observed in the top layer (1-3) m and at the point of contact with the subsurface water level which was in good agreement with the model results. The surface layer and the very lowest layers of the dump in contact with lateral flows experience the highest degree of weathering leading to depletion of species. The geophysical transformation of fly ash was also captured through the porosity change calculations and the results revealed that geochemical reactions do affect the porosity of fly ash during the weathering processes. These modelling results were in agreement with the hydraulic tests and salt leaching tests conducted during Sasol-Eskom ashbrine project in Phase I which suggested that salts captured in the ash will become mobile and leach from the fly ash over time. The data therefore indicates that ash dumps may not act as sustainable salt sinks. These findings may have some bearing on engineering decisions on fly ash reuse. From the above observations, it is apparent that release of large quantities of the salts in the ash depends on the extent of its interaction with brines being used for irrigation or with water, either through plug-in flow after a rainfall event or contact with groundwater. The results revealed effects of brine-water contact time with fly ash, the flow volume and velocity, the pH, the degree of saturation, hydrogeology and ash heap geometry as important factors that affect fly ash transformation and weathering. Overall, the ash heap modeling enhanced the understanding of the ash-brines interactions and demonstrated that leachate composition is determined by the following factors; (i) the mass flows from the pores of fly ash, (ii) the surface dissolution of the mineral phases, (iii) the various chemical reactions involved during the ash-brine and ash-water interactions, (iv) the interactions with a gas phase (atmospheric CO₂), (v) the composition of the initial fly ash, and (vi) by the leachate flow and hydrodynamics as captured in the conceptual model. Any ash handling system should therefore be designed to take these criteria into consideration to prevent environmental contamination. The modeling results also gave indications that the ash-brine co-disposal in dry ash systems would be an unsustainable way of locking up brine salts in the long run. In this Thesis, modeling results were used to support experimental data which further reaffirmed the important role hydrogeochemical modeling plays in liquid and solid waste management. Furthermore, hydrogeochemical modeling complements the work of analytical/environmental scientists as well as guiding the future solid waste management and engineering decisions. / Thesis (Ph.D.)-University of KwaZulu-Natal, Westville, 2012.

This study was conducted in South Africa. South Africa is the first country within the Southern African Development Community to have regulated plastic shopping bags waste through the imposition of both a standard on thickness and a levy. Given this scenario, the Plastic Bags Regulations present an illustrative case for researching complexity, uncertainty and controversies surrounding a new trend in environmental policy making, namely waste product regulation. The thesis focuses on understanding and investigating tensions, debates and responses emerging from the policy process as actors and actor-networks put not only the Plastic Bags Regulations asfocal actant (token) but also other actants and actant-networks as well. To this end, a research question that addressed environmental policies, tensions, debates and responses that informed the development of South Africa's Plastic Bags Regulations was spelt out. The research objectives included the need to: (I) analyse selected international environmental policy processes surrounding plastic shopping bags litter and waste regulation and how these influenced developments in South Africa; (2) identify actors, actants and actor/actant-networks that shaped and were being transformed by South Africa's Plastic Bags Regulations and explain the tensions, debates and responses arising in the policy processes; (3) identify environmental policy outputs and assess outcomes emerging from the formulation and implementation of South Africa's Plastic Bags Regulations; and (4) establish patterns in environmental policy process reforms around South Africa's Plastic Bags Regulations. The language of actors (human), actants (non-human) and actor/actant-networks brings to the fore the aspects of processes and relationships that exist around them. As such, insights from the actor/actant-network theory (AANT) were drawn upon to inform the research. AANT enquiry framework collapses binaries such as nature/society, art/science, structure/agency and global/local historically associated with a particular type of social theory. AANT also denies that purely technical, scientific or social relations are possible (the notion of quaSi-objects or token). Data sets were generated following' the Plastic Bags Regulations as token actant with time frames ranging from prior to, during and after the formulation of the regulations. Similarly, data analysis drew insights from AANT's four moments of translation namely problematisation, interessement, enrolment and mobilisation, with the intervention theory providing an evaluative perspective that complemented AANT. The findings were that after the promulgation of the first draft of the Plastic Bags Regulations in May 2000, tensions emerged around the nature of regulation (whether command and control - preferred by government or self regulation - preferred by industry and labour). In this regard the latter group raised concerns about jobs, income and equipment loss as well as the need to have a holistic approach to waste management rather than targeting a single product at a time whilst the former maintained that this would not be so. As such, education, awareness and stringent antilitter penalties were proposed by industry and labour as sustainable responses to the problem of plastic shopping bags waste rather than regulation. These debates continued and resulted in minor amendments to the original regulations as finalised by Government in May 2002. However, industry and labour continued lobbying government resulting in the conclusion of the Plastic Bags Agreement in September 2002 and the ultimate repulsion of the May 2002 regulations in May 2003. As revealed by this research, these responses led to broader social responses and further tensions as demand for plastic shopping bags went down by about 80% although an estimated 1000 jobs were lost and a number of companies lost equipment and business (with some closing down) following the implementation of the regulations. During implementation, debates emerged around the need to promote locally made carry facilities with two alternatives in sight namely: the Green Bag and the Biodegradable Plastic Bag. Debates also took place regarding enforcement of the new law resulting in the amendments of various pieces of legislation including the Environmental Conservation Act, Environmental Management Act and the Revenue Laws Act. Overall, a 15-year policy reform cycle and sub-cycles was determined. The research also established that the government considered the regulations a success and was already implementing simi lar initiatives to regulate other waste products, among them, used tyres, used oil and glass, confirming the trend towards waste product regulation in South Africa. From these research findings, a series of conceptual frameworks were drawn up to clarify the nature of tensions, debates and responses surrounding certain lead actors, actants and actorlactant-networks. Some of the conceptual frameworks that emerged around the actors and actor-networks include Organised Government, Organised Industry and Organised Labour. Conceptual frameworks that emerged around key actants and actant-networks include the Integrated Pollution and Waste Management, Plastic Bags Regulations as well as the discourses surrounding the Green bag and biodegradable plastic bags. The thesis concludes by reflecting on how the above and the grand actor/actant-network conceptual frameworks emerging from this research might be adopted with varying degrees of flexibility to research environmental and waste management policy processes in different waste product regulation set-ups. / KMBT_363 / Adobe Acrobat 9.54 Paper Capture Plug-in

MPH / Department of Public Health

MPH / Department of Public Health / The sanitary state of an area is largely influenced by waste handling practices of the residents and measures in place for safe waste evacuation and disposal. Despite strategies that the municipality and local communities have put in place; namely, collection of wastes in one central spot in some villages, littering of all types of wastes is still on the increase in many rural areas. The focus of this study was on common refuse generated at Khakhanwa Village, different waste management practices and the knowledge of villagers on the impact of poor refuse management. The study was carried out using the quantitative, descriptive methodology. A total population of 312 households participated. Data was collected using a structured questionnaire and ethical aspects were taken into consideration. Data was analysed descriptively using SPSS version 22.0. It is presented using graphs, tables and pie chart. The findings show that the respondents satisfactorily showed understanding of waste management and the impact of poor waste management. Due to lack of waste services, the majority of the residents resort to storing wastes within their homes, burning it and disposing of it in open dumping sites as major waste management practices. The most familiar wastes in Khakhanwa village are decomposable wastes, napkins and plastics. These findings call for strengthened waste services in rural areas and more waste education amongst all villagers. Policies on waste management need to be put in motion. Communities need to be equipped with the knowledge of reducing, reusing and recycling for the purpose of limiting wastes. Finally school curricula should be adjusted such that they inform learners about waste management from early ages.

MENVSC / Department of Ecology and Resource Management / The purpose of this study was to evaluate the strategic management of the Thohoyandou Block J landfill site. There are limited documented materials on strategic management of landfill sites in South Africa. As a result, this study sought to close this gap and expose new insights that it deemed to be of great importance in the management and operations of landfill sites. The capacity of a TBJ landfill site in terms of its efficiency in disposing waste, adherence to rules and procedures and the overall management of the site are the key areas of this study. The dominant types and sources of solid waste disposed at the TBJ landfill site, efficiency and effectiveness of operation of TBJ landfill site and operational challenges are the main areas covered in this study. The study adopted the mixed methods approach, involving both qualitative and quantitative research methods. Both primary and secondary data were acquired. Primary data were obtained through a questionnaire, an interview and field observation, using an observation checklist. Secondary data were obtained from ArcGIS Desktop Help 9.2 and documented materials from the Thulamela Local Municipality and the TBJ landfill site, the Integrated Waste Management Plan, Integrated Development Plan, TBJ landfill site’s monthly report, audit report and landfill site’s operating plan. Basically, field observation and a questionnaire completed by the waste manager, landfill operator and supervisor, were used to collect data on the operational challenges of TBJ landfill site and to obtain data on the efficiency and effectiveness at which the TBJ landfill site is operating. Waste pickers were interviewed and field observation was undertaken, to identify the dominant types and sources of waste disposed at the TBJ landfill site. A questionnaire completed by TBJ landfill operator, ArcGIS Desktop Help 9.2 for field measurement, reports of the amount of waste recorded and the municipality’s database, were utilized to elicit data regarding the determination of the capacity of TBJ landfill site. The results obtained revealed that the TBJ landfill site’s remaining capacity is 317 085 m3, which will be exhausted in the next 4 years. Plastics were found to be the dominant waste disposed at the TBJ landfill site, at 40%, followed by card-boxes, which constituted 32%. The dominant sources of solid waste generation in the TBJ landfill site were households, at 51%, followed by commercial, at 31% and industrial, at 11%. The absence of a weighbridge, to weigh loads of waste, frequent break down of equipment, lack of equipment required to operate the TBJ landfill site efficiently and the presence of fire hazards, were some of the / NRF