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Bulk chemical analysis of a combined municipal solid waste (MSW) bottom and fly ash from one facility showed most elements enriched over average soil abundances. Eleven minerals were identified using powder X-ray diffraction (XRD). Standard additions using XRD gave the following weight % minerals (±2σ): gypsum, 1.8 ± 1.9; hematite, 3.7 ± 1.7; quartz, 2.3 ± 1.0; spinel, approximately 3.5; halite, 0.5 ± 0.4; calcite 3.5 ± 1.9; rutile, 1.1 ± 1.3. Mullite, sylvite, anhydrite, and wüstite were also identified. The ash contained 18% minerals, 9% structural and adsorbed water, and 72% glass. Chemical sequential extraction showed that most Cr is present in phases resistant to chemical weathering, while significant Cd and Pb are sequestered in acid soluble (carbonate) phases. Little of these toxic trace metals are water soluble or in exchangeable surface sites. Batch reactors experiments showed that ash-water solutions were dominated by ions released by soluble salts. Three types of reactions are identified. 1) After rapid exhaustion of soluble salts, sodium and potassium exhibited nearly steady state behavior due to slow release of ions from less-soluble minerals and glasses. 2) Calcium and sulfate concentrations are controlled by either gypsum or anhydrite equilibrium after a few hours. Iron, aluminum, and manganese concentrations rapidly equilibrate with respect to hydroxide or oxide solid phases. 3) Silicon clearly shows temperature dependent kinetic behavior, but its rate of release into solution is slowed by back-reaction of a secondary silicate phase. Calculation of the CIPW normative minerals for MSW ash showed it to be analogous to a tholeiitic basalt. Over the long term, the concentrations of elements in MSW ash will continue to change and can be predicted by Goldschmidt's concept of ionic potential, and mineralogical changes can be predicted based on weathering of basalts. Comparisons of literature values showed that field MSW ash leachates contained higher concentrations of soluble salts and lower concentrations of magnesium, iron, zinc, copper, and nickel than uncombusted refuse leachates. Comparison of chromium, cadmium, lead, and arsenic concentrations did not clearly delineate which leachate contains more of these elements. / Ph. D.

The primary purpose of this study was to determine the efficacy of corporate-based recycling for communities without access to curb-side pick up of recyclable material. The secondary purpose was to use the taxonomy of behavior change strategies as devised by Geller et al. (1990a, b). The hypotheses of the study were as follows: 1) corporate-based recycling is an effective means of dealing with residential waste management in a rural community, 2) the effectiveness of one behavior change technique with a score of three (as proposed in the Taxonomy of Behavior Change Techniques) will be the same as an intervention package comprised of several techniques with a score of three, 3) the smaller the company, the more effective the intervention package and, 4) salaried employees will deposit more recyclable materials per person at the drop-off site than wage employees. Recycling drop off sites were established at the work place of rural residents as an alternative to curb-side pick up of recyclable material. Three sites chosen were located in a rural community in Southwestern Virginia. Two of the companies produced machine parts (n= 220, n=300). The third company produced printed material (n=32). Each company had both male and female wage and salaried employees with varying ages and levels of income. Recyclable materials (clear glass, green glass, brown glass and aluminum cans) were collected in four 33 gallon barrels in the parking lot of each company every Friday and weighed at the county collection center. In an attempt to motivate participation in the recycling program, the employees were informed of the availability of the barrels, given written prompts in the form of paycheck inserts and posters, and given group feedback in the form of a poster showing the weekly amount of each material collected at an individual company. One company also received a group meeting to promote consensus and to determine the weakness of the project. All prompts and feedback were given as a package at discrete periods of time in a multiple baseline design by groups. The intervention package was given twice at one site to determine the impact of repeated exposure to the intervention materials. Findings of the study indicated an erratic pattern of participation across the three sites. One site had such low participation that it was dropped from the study. The intervention packages did not significantly increase participation and the differences between wage and salaried employees were insignificant. It must be concluded that while some employees did participate in the recycling program refinements to both the interventions and the measurement techniques are needed. Directions for future research on the feasibility of corporate-based are discussed. / Master of Science

The separate land disposal of coal refuse and fly ash presents difficulties throughout the Appalachian region, both in terms of disposal costs per acre and in terms of its potential environmental impacts on soil, ground water, revegetation, and slope stability. The purpose of this study was to determine how fly ash addition to coal refuse would impact on certain geotechnical properties of the refuse disposal piles, and whether the refuse-fly ash blends would be suitable as co-disposed materials. Accordingly, the compaction, permeability and shear strength characteristics of the refuse-fly ash blends were experimentally determined for varying fly ash percentages. The compaction test results indicated that, with increasing fly ash, the maximum dry density of these blends marginally decreased. The permeability test results showed that the permeability of the test specimens progressively decreased with the increase in fly ash. The shear strength results demonstrated that the addition of fly ash did not significantly influence the shear strength of the refuse. The critical factor of safety determined during slope stability analysis revealed that the tested slope geometries were stable for long term, drained conditions (using the STABGM computer program). The volume change analysis determined that there was a minimal expansion in the volume of refuse when it was blended with fly ash. However, it may be noted that all the stated results depend on a number offactors, including the nature of the refuse and fly ash used. Therefore, these findings would be specific to bulk blends of coal refuse and fly ash only. In general, this study indicates that fly ash can be beneficially reused with respect to the geotechnical properties evaluated. Co-disposal of fly ash and coal refuse may be a reasonable alternative to present disposal methods. / Master of Science

D. Tech. Civil Engineering. Tshwane University of Technology, 2011.

A Reverse Production System (RPS) is a network of transportation logistics and processing functions that collects, refurbishes, and demanufactures for reuse/recycle used or end-of-life products. In this thesis, I focus on the RPS strategic decisions of a processor and collectors when the collection network and contracts for materials can be co-designed. The research problem is motivated by the need of material processors to ensure a consistent flow of material from collectors at a cost that will enable them to be competitive with virgin raw materials. The failure to develop a cost-effective collection network can lead to poor overall economics where expensive processing assets are not fully utilized. The three key problems from the processor s point of view are: 1) how to design a strategic collection network; 2) how to be competitive in the collected materials market place when significant investment is at risk; and 3) how to avoid overpaying for materials when collectors are in regions with different volumes and costs. The multiple goals of this research are: 1) to integrate the contract and strategic network design in RPS; 2) to develop contract mechanism designs to improve the performance under incomplete information and study the value of information (complete vs. incomplete); and 3) to introduce and analyze new strategic network models for effectiveness in solution quality and time. Concepts of mathematical optimization, contract theory, and game theory are utilized in proposing models that couple contract and network problems, including lump sum and variable volume contracts.

Thesis (MSc (Geography and Environmental Studies))--University of Stellenbosch, 2004. / 103 Leaves printed on single pages, preliminary pages i- viii and numbered pages 1-94.I ncludes bibliography, ADDENDUM A: Questionnaire document used in the research; list of tables and figures. / Digitized at 330 dpi black and white PDF format (OCR), using KODAK i 1220 PLUS scanner. / ENGLISH ABSTRACT: The subject of waste management is one that evokes a variety of debates due to the overwhelming implications on the environment and on health that are associated with the management of waste. In developing urban areas associated with informal settlements, environmental problems emanating from household solid waste management predicaments such as illegal dumping, littering and overfilling of skips have become a permanent feature. This is also the case in Lwandle a developing township in Helderberg Municipality, Western Cape. This study looks into the waste management system in Lwandle with the aim to investigate institutional settings, related socio-economic factors and resultant community perceptions, and avenues for the use of environmental education and community participation. The results show waste collection to be the responsibility of the Helderberg Municipality, but the collection operation is undertaken by a private contractor. The nature of waste collection under these arrangements is mainly determined by the nature of housing and associated accessibility. Consequently, three main methods of waste collection are used: kerbside collection; communal collection where there is use of bins and communal collection where there is use of skips. These have varying efficiency among the nine housing areas. Socioeconomic conditions, which were marked by a high level of unemployment and low incomes, determine societal attitudes. These underpin finer variations and detailed conditions of waste collection. These, in tum, establish the framework for suitable environmental education and community participation. The latter was found to be minimal. Thus, a holistic approach to the improvement of waste management that first acknowledges inherent broader societal problems such as housing and unemployment is proposed as part of the recommendations. This approach then concentrates on finer aspects such as contracts for waste collection, aspects of waste collection dependent on waste stream nature of housing areas, appropriate environmental education and community participation. / AFRIKAANSE OPSOMMING: Afvalbestuur is 'n onderwerp wat 'n verskeidenheid van debatte uitlok vanwee die geweldige implikasies vir die omgewing en vir gesondheid wat met afvalbestuur geassosieer word. In ontwikkelende stedelike gebiede wat met informele behuising geassosieer word, het omgewingsprobleme soos onwettige storting, die strooi van rommel en oorvol stortbakke wat verband hou met die hantering van vaste afval uit huise 'n permanente kenmerk geword. Dit is ook die geval by Lwandle, 'n ontwikkelende dorpsgebied te Helderberg, in die Wes-Kaap. Hierdie studie beskou die afvalbestuursisteem in Lwandle met die doel om institusionele omgewings, verwante sosio-ekonomiese faktore en die persepsies van die gemeenskap wat daaruit ontwikkel, asook moontlikhede vir die gebruik van omgewingsopvoeding en gemeenskapsbetrokkenheid, te ondersoek. Die resultate van die ondersoek toon dat die Helderberg Munisipaliteit verantwoordelik is vir die insameling van afval, maar dat die insameling deur 'n private kontrakteur uitgevoer word. Onder sulke omstandighede word die aard van afvalinsameling hoofsaaklik deur die aard van die behuising en die verwante toeganklikheid bepaal. Daarvolgens is daar drie hoofmetodes van insameling, wat deur verskillende grade van effektiwiteit gekenmerk word, vir die nege behuisingsgebiede: sypaadjie versameling; kommunale versameling in dromme; en kommunale versameling in stortbakke. Sosio-ekonomiese omstandighede, wat gekenmerk word deur 'n hoe mate van werkloosheid en lae inkomstes, bepaal gemeenskapshoudings wat deur die verskillende maniere van afvalverwydering tot stand kom en ondersteun fyner variasies en gedetailleerde omstandighede van afvalinsameling. Dit bepaal weer die raamwerk vir gepaste omgewingsopvoeding en die deelname van die gemeenskap. Die studie het getoon dat laasgenoemde minimaal is. 'n Holistiese benadering tot die verbetering van afvalbestuur, wat eerstens inherente breer gemeenskapsprobleme soos behuising en werkloosheid erken, word dus as deel van die aanbevelings voorgestel. Hierdie benadering konsentreer vervolgens op die fynere aspekte, soos kontrakte vir afvalinsameling, aspekte van afvalinsameling, gepaste omgewingsopvoeding en gemeenskapsdeelname.

Resource recovery is an attractive alternative to the waste disposal problem. The chief by-product of this process, refuse derived fuel (RDF) can be co-fired in traditional coal burning facilities. The cement industry is a potential user of RDF. This study, based on a test burn done at Texas Industries Inc. in Midlothian, Texas, demonstrated the technical, environmental, and economic feasibility of using RDF fuel in a cement kiln. Technically, the cement showed no deleterious effects when RDF was substituted for coal/natural gas at 20% by Btu content. Environmentally, acid rain gases were reduced. Economically, RDF was shown to be a cost effective fuel substitute if a resource recovery facility was erected on site.

Research estimated toxicity of refuse-derived fuel fly ash (RDF-FA) on two earthworms species, Lumbricus terrestris and Eisenia foetida. Specific objectives were to: (1) Compare their 14-day LC50s under light and dark conditions; (2) separate toxicity due to osmotic, pH and physical factors from that of heavy metal contaminants; (3) compare relative differences of artificial soil and commercial soil as exposure media for evaluating toxicity to earthworms. The 14-d LC50s for L. terrestris in dark and light were 57.0 and 48.34 % RDF-FA, and 59.25 and 41.00 % RDF-FA for E. foetida using artificial soil. All of the toxicity resulted from heavy metals within the RDF-FA. Using L. terrestris, the LC50s for artificial soil and commercial soil were 52.30 and 64.34%.

Submitted in fulfillment of the requirements for the Master of Information and Communications Technology, Durban University of Technology, Durban, South Africa, 2017. / The future of modern cities largely depends on how well they can tackle intrinsic problems that confront them by embracing the next era of digital revolution. A vital element of such revolution is the creation of smart cities and associated technology infrastructures. Smart city is an emerging phenomenon that involves the deployment of information communication technology wares into public or private infrastructure to provide intelligent data gathering and analysis. Key areas that have been considered for smart city initiatives include monitoring of weather, energy consumption, environmental conditions, water usage and host of others. To align with the smart city revolution in the area of environmental cleanliness, this study involves the development of a web based smart city infrastructure for refuse disposal management using the design science research approach. The Jalali smart city reference architecture provided a template to develop the proposed architecture in this study. The proposed architecture contains four layers, which are signal sensing and processing, network, intelligent user application and Internet of Things (IoT) web application layers. A proof of concept prototype was designed and implemented based on the proposed architecture. The signal sensing and processing layer was implemented to produce a smart refuse bin, which is a bin that contains the Arduino microcontroller board, Wi-Fi transceiver, proximity sensor, gas sensor, temperature sensor and other relevant electronic components. The network layer provides interconnectivity among the layers via the internet. The intelligent user application layer was realized with non browser client application, statistical feature extraction and pattern classifiers. Whereas the IoT web application layer was realised with ThingSpeak, which is an online web application for IoT based projects. The sensors in the smart refuse bin, generates multivariate dataset that corresponds to the status of refuse in the bin. Training and testing features were extracted from the dataset using first order statistical feature extraction method. Afterward, Multilayer Perceptron Artificial Neural Network (MLP-ANN) and support vector machine were trained and compared experimentally. The MLP-ANN gave the overall best accuracy of 98.0%, and the least mean square error of 0.0036. The ThingSpeak web application connects seamlessly at all times via the internet to receive data from the smart refuse bin. Refuse disposal management agents can therefore query ThingSpeak for refuse status data via the non browser client application. The client application, then uses the trained MLP-ANN to appositely classify such data in order to determine the status of the bin. / M