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Two complex wastes were considered for biological conversion into a marketable product. One waste, peat runoff water (the waste-water that remains after the mining of peat), was found to be unsuitable for biological conversion to any product since it contained an insufficient quantity of carbon. The other waste, NVR (non-volatile residue, the major waste from the manufacture of nylon 6$ sp prime 6 sp prime$), was found to be a suitable carbon and energy source for the production of PHB (poly-$ beta$-hydroxybutyric acid) by Pseudomonas cepacia ATCC 17697. A general approach to the development of complex toxic wastes as fermentation substrates was formulated. / NVR was found to be toxic to microorganisms. None grew in enrichment culture containing 2.0% NVR. P. cepacia was the most resistant microorganism found. It could grow well in up to 1.3% NVR. It also grew on butanoic, pentanoic, and hexanoic acid as well as 6-hexanolactone. These were found to be the major toxic components of NVR. P. cepacia was grown in a NVR-limited chemostat with a NVR feed concentration well in excess of the toxic NVR concentration. In nitrogen-limited, batch fermentation on fructose, P. cepacia accumulated PHB in excess of 50% of its dry weight. A 2-stage chemostat process for the production of PHB from NVR by P. cepacia was investigated with encouraging results.

This thesis examines the regional electronic and electrical waste (e-waste) recycling network in Malaysia and Singapore, with a secondary focus on the articulations of informal labour within the network. I argue that there is a need to theorise production networks post-consumption; i.e. to focus on the activities and processes that occur after a commodity is consumed and subsequently discarded. I argue that discarded e-waste are not ‘value-less’ waste, but instead embody value (specifically latent use value), and have the potential to be re-inserted as ‘raw materials’ into production networks through the processes of recycling. Also, key to the processes of value (re)creation, enhancement and capture is the labour process. I examine informal labour by focusing on karung guni (a local term for the rag-and-bone man) – analysing their critical role in value (re)creation in this regional e-waste recycling production network through the lens of petty commodity production. I argue that karung guni are constitutive of this production network through their collection and primary processing of e-waste, which forms the basis for subsequent value creation, enhancement and capture by downstream actors. Conceptualising karung guni as petty commodity producers – who own both the means of production and their own labour power – is significant in problematising as not so straightforward the separation of capital and labour into discreet categories as normally presented in global value chains (GVC)/global production networks (GPN) approaches. This thesis makes four significant contributions to the GVC/GPN literature. First, it recognises activities beyond the point of consumption (which has been the focus of present GVC/GPN research). Second, it conceptualises the constitutive role of informal labour in the development and structure of production networks. Third, it emphasises the continued relevance of the state. Fourth, by adopting a multi-sited case study method, it contributes to debates on how to carry out GVC/GPN research.

An annular control valve was developed for the extrusion of wood slurries and polymers. The objective was to determine the optimal valve geometry: (1) to provide a linear pressure drop across the valve as a function of valve opening and (2) to eliminate the problem of valve plugging caused by the high solid content of the wood slurries. The approach was to model the non-Newtonian flow in a plasticating single-screw extruder. A finite-difference scheme was developed to model the flow through annular surfaces. The two flow equations were solved simultaneously and a parametric study was performed to determine the optimal valve geometry. The valve operability was evaluated for the extrusion of various mixtures of low-density polyethylene, sawdust, wood flour, and vacuum bottom. The experimental results were in good agreement with the model. In general, a linear valve characteristic was observed and the problem of valve plugging was not evident.

This thesis examines the relationships people have with rubbish in everyday life. Focusing on domestic recycling policy and practice, environmental concern and action is explored as a sociological problem in a way that moves beyond the individualising paradigms that dominate environmental discourse for behavioural change. In its place, this thesis argues that better explanation may reside in the social context of embedded practices, and how they get enacted in daily life. Beginning with a historical overview and evaluation of current policy, this thesis re-imagines domestic recycling as a complex socio-technical system involving the engagement of different actors. Conducted at the boundaries of sociology, this thesis draws on empirical and theoretical ideas that extend across disciplines. Methodologically the research has been grounded on a principle of mixed methods pragmatism, exploiting the Sequential Explanatory mixed methods research design. Conducted across two phases, Phase One involved the secondary analysis of the Scottish Household Survey and Phase Two the collection and analysis of qualitative data using the Diary- Interview method. The first phase was a macro- analysis of recycling practices in Scotland. The main results of this analysis are presented in Chapter 4, which built a Binary Logistic Regression model, using the Scottish Household Survey, to predict the characteristics of Scottish households likely to engage in recycling behaviour. In addition to identifying the social and structural dimensions of recycling in Scotland, this analysis also enabled a research site to be selected for Phase Two of the study. Chapters 5 and 6 respond to the macro- analysis by accounting for the micro- aspects of recycling practices by looking at the problem inductively. Using qualitative data analysed in Phase Two, these two chapters are based on the idea that how people value the environment is relevant for understanding contemporary recycling practices. Chapter 5 considers the explanatory usefulness of environmental ethics, values and citizenship for explaining why some households engage in environmental behaviour, but others do not. In Chapter 6 these arguments are developed further with a more detailed discussion about how household recycling practices get enacted in everyday life. Using evidence from the data, this chapter considers why commitment to ‘doing’ recycling varies between people and examines recycling as formed, cultivated and maintained habitual behaviour. Taken together the three data chapters try to show that, rather than be an inconsequential feature of normal domestic life, recycling is a practice deeply-rooted in wider social patterns and structural forces. In the final chapter, all of the micro- and macro- findings are integrated together and concluded, along with some reflections on the multidimensionality of contemporary recycling practices in the home, and what this might mean for policy and future research.

Thesis (M.A.)--University of North Carolina at Greensboro, 2007. / Title from PDF title page screen. Advisor: Zhi-Ju Liu; submitted to the Dept. of Geography. Includes bibliographical references (p. 83-89).

CAPES / A problemática da geração de resíduos industriais vem se agravando, principalmente pelo fato de que somente uma pequena parcela desses resíduos é corretamente tratada e devidamente destinada em locais próprios. Um exemplo de resíduo com grande potencial poluidor é a manipueira, efluente líquido gerado em grandes quantidades no processamento de mandioca para a produção de farinha e de fécula. A manipueira contém uma elevada carga orgânica na sua composição, com alto teor de fécula residual, resultante do baixo rendimento do processo de extração. Outro grande problema ambiental é a perda de nutrientes aplicados no solo por meio de fertilizantes, principalmente do nitrogênio, decorrente dos processos de lixiviação pela água das chuvas e volatilização pelo aquecimento do solo, que trazem prejuízos financeiros aos agricultores e danos ambientais pelo excesso de nutrientes levados aos corpos hídricos. Aliando-se essas duas questões, o objetivo desse trabalho foi preparar e caracterizar biofilmes à base de manipueira pura, e também de manipueira com a incorporação dos aditivos poli-(álcool vinílico) e alginato de sódio, avaliando-se assim, a influência desses aditivos nas características finais dos biofilmes. Após esta etapa, avaliou-se qual dos biofilmes produzidos obteve características compatíveis para a imobilização da caulinita intercalada com ureia, visando avaliar esse conjunto como fertilizante de liberação lenta de nitrogênio, que prioriza a liberação gradual do nutriente. A partir da caracterização da manipueira utilizada, determinou-se que a mesma possui um teor de 3% de fécula na sua composição, dessa forma, o resíduo foi utilizado como solução filmogênica para formação dos biofilmes. Esses biofilmes foram caracterizados e apresentaram baixas propriedades de barreira ao vapor de água, entretanto, os biofilmes de manipueira pura e de manipueira com poli-(álcool vinílico) possuem boas propriedades mecânicas e alta estabilidade térmica. Os biofilmes de manipueira com alginato de sódio apresentaram características mecânicas inferiores aos citados acima e com menor estabilidade térmica. A partir das características apresentadas, o biofilme de manipueira pura foi escolhido para ser o meio imobilizante da caulinita intercalada com ureia, onde, além da caracterização realizada como nos demais biofilmes, foi também avaliada a liberação do nitrogênio por meio de ensaios de lixiviação e de aquecimento. Observou-se que nos ensaios de lixiviação a imobilização não foi efetiva, perdendo 73,37% do nitrogênio incorporada já no menor tempo empregado no ensaio, entretanto, no ensaio de aquecimento, o biofilme de manipueira pura apresentou uma alta imobilização até 170 ºC, com uma perda de nitrogênio de somente 14,93%. A análise dos resultados mostra que os biofilmes à base de manipueira são uma alternativa viável de reaproveitamento desse resíduo, apresentando boas características, entretanto, quando o emprego é a imobilização da caulinita intercalada com ureia é necessário um maior estudo buscando meios para reduzir as perdas por lixiviação. / The problem of industrial waste generation has aggravating mainly by the fact that only a small portion of that waste is properly treated and properly designed in suitable places. An example of waste with high pollution potential is manipueira, liquid effluent generated in large quantities in manihot processing for the production of flour and starch. Manipueira contains a large organic load in its composition, with high levels of residual starch, resulting in low yield of the extraction process. Another major environmental problem is the loss of nutrients applied to the soil through fertilizers, especially nitrogen, resulting from leaching processes by rain water and volatilization soil heating, which brings financial damage to farmers and environmental damage by excess nutrients carried to water bodies. Allying these two issues, the objective of this work was to produce biofilms based on pure manipueira, and too manipueira with incorporation of additives poly (vinyl alcohol) and sodium alginate, thus assessing the influence of these additives in the final characteristics of biofilms. After this step, we evaluated which of biofilms produced consistent characteristics obtained for the immobilization of kaolinite intercalated with urea, to evaluate this set as a slow release fertilizer nitrogen, which prioritizes the gradual release of the nutrient. From the characterization of cassava used, it was determined that it has a content of 3% starch in composition, thus the residue was used as filmogenic solution for the formation of biofilms.These biofilms were described and presented barrier properties to water vapor low, however, the biofilm manipueira and pure manipueira and manipueira with poly (vinyl alcohol) have good mechanical properties and high thermal stability. Biofilms manipueira with sodium alginate showed inferior mechanical characteristics to those cited above and with lower thermal stability. From the characteristics presented, the biofilm pure manipueira was chosen to be the means of immobilizing kaolinite intercalated with urea, which, besides the characterization performed as in other biofilms was also investigated the release of nitrogen through leaching tests and heating. It was observed that the leaching tests was not effective immobilization, losing 73.37% of the nitrogen already incorporated in the shortest time employed in the assay, however, a test of heating, the biofilm pure manipueira showed high immobilization to 170 ° C, with a loss of nitrogen of only 14.93%. The analysis suggests that biofilms based manipueira are a viable reuse of this waste, with good features, however, when employment is immobilization of kaolinite intercalated with urea requires a larger study looking at ways to reduce leaching losses.

Thesis (Master of Engineering in Chemical Engineering)--Cape Peninsula University of Technology, 2018. / The rate of waste electrical and electronic equipment (WEEE) is growing at an alarming rate, especially in countries where markets are saturated with huge quantities of new electronic goods. Printed circuit boards (PCBs) are a substantial portion of the value contained in waste from WEEE although they are only 6% of the total weight. It is reported that WEEE is currently the fastest growing waste stream in South Africa as the general population’s access to electronic goods in the last decade has increased, especially access to mobile phones. PCBs are found in any piece of electrical or electronic equipment and consist of various metals including precious metals such as gold (Au), silver (Ag) and palladium (Pd). It is reported that gold has the highest economic incentive at 15,200 $ per ton of PCBs. The rapid introduction of new and advanced technology into mobile phones has caused mobile phones to have a relatively short life span, 1 to 2 years to be exact. Mobile phones printed circuit boards (MPPCBs) have more Au content compared to computer circuit boards. They contain 350 g/ton Au whereas computer (PC) PCBs contains 250 g/ton. This research project will recover gold from waste mobile phones PCBs pregnant ammonia thiosulphate leach solution using copper cementation. The cementation process is preferred to all the other technologies of metals extraction from solution due to ultrahigh purity metals that can be obtained and to the less consumption of materials and energy. Electronic parts on the PCBs were manually removed using pliers and screwdrivers. PCBs were then cut to smaller pieces of about 2 x 2 m. The pieces were crushed and milled respectively. Some of the particles were recycled back to the crusher to get finer particles. The particles were separated to particles of sizes between 0 and 1350 μm using a shaker. The comminuted fractions of the PCBs were then used in the leaching step. Batch cementation experiments were performed by bubbling N2 in glass reaction vessel with a working volume of 0.5 L. The reactor was connected to a circulating water bath for temperature control. The recovery percentage of gold at various temperatures, agitation speeds and different amounts of copper powder used, was determined while pH was monitored. The temperature was varied at 30 °C, 40 °C, and 50 °C and the agitation speeds at 300 RPM and 900 RPM. Copper powder was added at 0.5 g/L, 1 g/L, and 1.5 g/L. Gold concentrations were measured by atomic adsorption spectrophotometer (AAS). Scanning electron microscope (SEM) and Energy-dispersive x-ray spectrometry (EDS) analyses of the copper powder after cementation (precipitates) were used to determine the surface morphology and to evaluate the quantitative aspect of the precipitate. It was found that the recovery of gold from ammonia thiosulphate leach solution was greatly affected by agitation speed. At an agitation speed of 900 rpm, 40 °C and 0.5 g of Copper powder, 96% of the gold was recovered from the leach solution. The cementation rate increased as temperature was elevated from 30 to 40 °C, but slightly decreased as the temperature reached 50 °C. The change in experimental conditions affected the gold concentration on the precipitate recovered. This study will provide a possible solution to the WEEE problem and more specifically mobile cell phones, in South Africa.

Food waste is one of an organic waste and contains the value of recycling and reusing. EPA shows that there are almost the amount of 4500 tons food wastes which is about 36~64% in households in Taiwan everyday. Therefore, if food wastes could be reused again, not only greatly reducing the amount of waste, decreasing the problem of odor from progressing food wastes, but also increasing the using year of landfills and incinerators. Furthermore, it can develop fully the value of multiple reusing in recycling. The study is forced on questionnaires for the residents of the city of Kaohsiung and Taichung, to know the present of recycling of food waste and its difficulty in executing a strategy. Conferring the willingness to pay and the willingness to accept of food waste recovery and if the price is different or not by Contingent Valuation Method (CVM), and moreover evaluating the potential benefit. The results of the study are as following: there are conspicuous difference in ¡§if doing something about recovery¡¨ ¡§the way of recovery¡¨ and ¡§if see any inspectors examine the classification of refuse¡¨. The most difficulties of recovery food waste in both cities are ¡§its odor and breed mosquito and fly easily¡¨ and ¡§not knowing clearly what materials should be recovered or not¡¨. About the price of the willingness to pay and the willingness to accept, the major answer shows ¡§No, I would not.¡¨ from this questionnaires. On the other hand, answers of ¡§Yes, I would like.¡¨ all hope that the pay less is better and the compensation more is better. The price of the willingness to pay of Kaohsiung residents is NT$ 41.8 dollars, and Taichung residents is NT$ 45.3 dollars. Otherwise, the higher environmental conscious the Kaohsiung residents have, the higher willing to pay. At the same time, the difficulty of recovery food waste is low comparatively. In addition, ¡§occupation¡¨ ¡§family revenue per month¡¨ ¡§cooking per week¡¨ have effect on the price of the willingness to pay and the willingness to accept. In the result of regression, some of variable parameters could affect the price of the willingness to pay. It maybe provides society for reference according the benefit in the estimating of regression. Therefore, the study hopes to provide the decision-maker more clear environmental and economical information through evaluate and analyze the willingness of pay of food waste. Furthermore, it maybe help the government to make a future policy in order to practice the food waste recovery indeed and carry out the target of reducing the amount of waste and resources recovering for a sustainable resources of food waste.