Chemical and allied industries produce significant quantities of chlorinated wastes each year. Thermal treatnent of these chlorinated wastes has a long and controversial history. The most common and contentious method of waste destruction is incineration. Although waste incinerators are designed to provide greater control over the combustion process, toxic products are inevitably formed from incomplete combustion and released in stack gases and other residues. The most notable group belonging to the products of incomplete combustion (PICs) are dioxins and furans. The fact that oxygen is an integral part of the molecular structure of dioxins and furans suggests that the formation of these particular PICs may be reduced or avoided by minimizing or completely excluding oxygen from thermal waste treatment. Pyrolysis using induction heating is a relatively new technology that has shown much promise from the initial work performed by Pillay (2001). This research was an extension of that study, and investigated equipment and process optimization as well as macroscopic modeling of different systems. The objective of this study was to establish the technology of pyrolysis using induction heating as a competitive alternative to existing waste destruction systems. The novel approach of pyrolysing compounds using induction heating was demonstrated by destroying chlorinated aliphatic, aromatic and a mixture of these compounds. These experiments were conducted at atmospheric pressure in a tubular laminar flow reactor (5.2cm I.D) under a thermally transparent argon atmosphere. In this system heat was generated in an embedded graphite tube using induction heating. Thermal degradation occurred through the bombardment of the compounds by the photons emitted from the heated graphite tube. The compounds were pyrolysed at temperatures ranging from 330°C to 1000°C and at mean residence times from 0.47s to 2.47s. In addition to these process variables the effects of reactant concentration and additives were investigated The major species formed from this thermal treatment were solid carbon black and gaseous hydrogen chloride. Destruction efficiencies (DE) of the order of 99.9999% (six nines) and greater were obtained for the different feed mixtures at their respective operating conditions. A minimum DE of six nines adequately satisfies the regulation set by the Environmental Protection Agency (EPA) for successful waste destruction. / Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2004.

The use of municipal refuse (RDF) as fuels has received widespread attention for reason of its energy equivalence and the increasing lack of available landfill sites. The principal obstacle to the construction of combustion facilities is that RDF produces toxic compounds, including heavy metals and such organic compounds as PCDD and PCDF. In this study, the emissions of metal and organic compounds were investigated under oxygen deficient and oxygen surplus conditions for the RDF and such high volume contributors as office papers and magazines. The principal metal emissions of the RDF were Al, Ca, K, Si, and Zn. Magazines significantly contribute B, Mg, Mn, Ti emissions, whereas office papers contributed Ti and Zn emissions. The metal emissions were not significantly different between oxygen deficient and oxygen surplus conditions at a temperature of 750��C. The combustion of RDF produced a full range of PCDFs and PCDFs, the source of which was determined to be RDF, papers, and even untreated wood combustion effluents in the parts-per-billion range. In contrast to metal emissions, emission rates were higher under the oxygen surplus condition than for the oxygen deficient condition and PCDD and PCDF emissions were significant in relation to the chloride contents of fuel, rather than by fuel type as was the case for the large volume contributors. With the exception of Hg, Se, S, Sr, and Pb, the metal emissions were largely derived from the particles in the effluent. / Graduation date: 1993 / Text is slanted on original. Best scan available.

No description available.

De-inking sludge generated from pulp and paper industry is considered hazardous since it may contain heavy metals such as Cd, Cr, and Pb. Hence, the de-inking sludge needs to be treated before being disposed of. Sludge combustion is a proven disposal technology, which generates fly ash containing a portion of the heavy metals that may leach out under uncontrolled conditions. The aim of this thesis is to implement a new multi-zone temperature combustion technique (Low-High-Low temperature combustion, LHL) to help contain and immobilize the heavy metals within fly ash particles. During the LHL, the waste will be initially fed into a low-temperature zone (<1100 K) and then subjected to the high-temperature treatment (~1480 K) that will be followed by another low-temperature zone (~1100 K). / This dissertation describes the detailed design and construction of a novel pilot-scale combustion facility, called the Multi-Mode Combustion Facility (MCF), used as a multidisciplinary research tool for investigating the thermal remediation of contaminated solid residues. The MCF is capable of operating in two different modes: Fluidized-Bed combustion mode (FBC) and Single burner furnace mode (SBF). However, this project focuses on the FBC mode (minimum fluidization velocity of 0.42 m/s and bed temperature of 1073 K). / This research compares the combustion characteristics of de-inking sludge obtained in the LHL and in the conventional combustion techniques. The following properties of particulates were studied: morphological evolution of solid particles, structural porosity, metals interactions with fly ash particles, and leachability. / The LHL's final supermicron spherical fly ash went through a molten phase with submicron particles attached to the fly ash particles surfaces. Thus, reducing its porosity to 19%. However, the amorphous final fly ash obtained in the conventional technique reveals 32% porosity. It was found that the physical characteristics of the final LHL's fly ash are the main cause for the reduced heavy metals leachability rates of 0.18, 0.046, and 0.92% for Cd, Cr, and Pb, respectively. The conventional technique had 53.28, 16.79, and 5.20% of Cd, Cr, and Pb respectively, leaching out due to the high porosity percentages. In conclusion, the LHL technique allows for controlling the heavy metals emission from FBCs, while using a waste to energy approach and maintaining environmentally acceptable gas emission levels.

No description available.

published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management

本研究聚焦2009年到2013年，中國廣州的一場圍繞垃圾處理展開的社會運動。運動最初是當地居民動員起來反對市政府垃圾焚燒項目的鄰避抗爭。勝利後，運動領袖成立了一個環保組織，和政府從對抗走向合作，力圖推动焚燒技術以外的替代性垃圾治理方案。不過，儘管政府和環保者致力於解決垃圾，垃圾問題在消費社會中始終無法消除。本研究試圖理解後社會主義中國的綠色治理和環保行動之間的對抗與合作。 / 首先，我分析當代中國高速城市化和消費社會急速發展所帶來的垃圾危機。然后，我檢視圍繞垃圾焚燒技術的主要爭議，並描繪廣州居民是如何針對政府計劃中的垃圾焚燒項目做出抗爭的。我指出，他們結合地方性知識和科學話語，將自己建構為"常民專家"，對全球性的焚燒科技的"地方適用性"作出成功挑战。接下來，我提供一個民族誌，追溯抗議成功后運動的歷史軌跡。我注意到，通過成立一個環保組織"EC"，反焚運動走向合法化、組織化和制度化，抗爭被體制吸納，轉變為參與協助國家環境治理的運動。最後，我描繪EC與广州政府聯手推動的垃圾分類運動。指出，國家在此運動中的尷尬身份、以利潤為導向的回收市場影響、理想化的垃圾分類知識與普通民眾的知識存在斷裂，都使得推動垃圾分類異常艱難。 / 通過展示運動變遷與國家治理轉型相互交織的辯證关系，本研究挑戰了國家與社會的二元對立，指出在國家在治理轉型過程中不斷收編反抗的行動和話語，而於此同時反焚者又在不斷生產新的另類知識做出挑戰。此外，本研究還貢獻於對廢棄物的理解，將廢棄物視為是一個動態的範疇，國家、市場、科學技術、普通消費者、環保行動者等多個行動者共同生產、競爭、建構其意義。還有，本研究對於科技知識的普遍性的探討，對科學技術研究領域做出了貢獻。 / This is a study on social movements that focused on waste treatment in Guangzhou, China from 2009-2013. The campaign began as a NIMBY (Not-In-My-Backyard) movement that mobilized community residents to protest against municipal government's proposed incineration projects. After its success, the movement leaders changed their dissident role to form an environmental protection NGO, collaborating with the state to explore alternative waste treatment solutions other than incineration. However, despite of the politicians and activists' attempt to eliminate waste, waste continues to exist in tandem of our consumption spree. I endeavor to understand the contradiction as well as collusion between green governance and environmental activisms in post-socialist China. / Firstly, I analyze the garbage crisis caused by the rapid urbanization and the dramatic growth of consumer society in contemporary China. Then I examine a few major technological controversies of waste incineration and depict how the activists protest against the pro-incineration government. I argue that through deploying local knowledge, the activists, as "lay experts", successfully challenged the "local appropriateness" of the global technology of incineration. Next, I provide an in-depth ethnography of the transformation of this campaign after its initial success. I notice that by taking the form of an environmental NGO called "EC", the campaign was legitimized, institutionalized and incorporated into the state’s governance framework. The environmental activism became an aid to the state’s green governmentality. Lastly, I take a detailed look at the waste classification campaign jointly launched by Guangzhou government and EC. I point out that the ambiguous role of the state in this campaign, the profit-oriented recycling market together with the idealist knowledge/practice systems of this project make this campaign extremely difficult. / My research challenges the state-society dichotomy by showing that the trajectory of the campaign is dialectically entangled with the transformation of the state’s governance. The state constantly incorporates the resistance and alternative discourses produced in the movement, whereas the activists keep on producing alternative knowledge to challenge the state. Moreover, this study deepens the understanding of waste by considering waste as a flexible category in which various actors such as state, market, technosicence, consumers as well as the environmental activists are producing, competing and reconstructing its meaning. Also, my discussions of the universal knowledge of science contribute to the field of science and technology studies. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / 張劼穎. / Parallel title from added title page. / Thesis (Ph.D.) Chinese University of Hong Kong, 2015. / Includes bibliographical references (leaves 220-236). / Abstracts also in English. / Zhang Jieying.

The absence or unavailability of solid waste disposal facilities and service in rural areas of the UThukela District Municipality (UTDM) compelled residents to adopt many disposal practices. This included open burning of waste, which leaves residues in the form of waste ashes. Some heavy metal and hazardous substances remain active in these waste ashes. In this study, the impact of Solid Waste Disposal Practices (SWDP) on the environment was investigated by evaluating the effect of waste ashes on plant growth. The research was directed towards the evaluation of the environmental impact of solid waste disposal practices by households in these rural areas of KwaZulu-Natal (South Africa), on the growth of Zea Mays (Maize) plants. Rural maize farmers dominate the district of UTDM because it is a good agricultural area with great potential for high rainfall in summer, moderate temperatures, good soil and moderate slopes. The method selected to achieve research objectives was the evaluation of the influence of waste ashes, as by-products of SWDP, on plant growth. This was achieved by, determining soil fertility; collecting household solid waste from different rural families to determine the composition (including already burnt ash, plastic ash and wood ash; analysing the chemical composition of traditional ashes collected from sites where it was burnt (waste ashes); applying the evaporation pan test; mixing waste ashes and other additives with soil in planting pots in equal parts; planting Zea Mays in winter and summer; and lastly, monitoring and measuring agronomic parameters of plant growth on a regular basis. The selected additives to the in situ soil were fertilizer, compost, waste ash, plastic ash and wood ash. Pots with soil only (no additive added) served as control. The findings revealed that plants exposed to wood, waste and plastic ash struggled to grow when compared to plants grown with fertilizer, compost and soil only. The impact of all waste ashes on plant growth was negative in both seasons and some of the agronomic parameters were unable to sprout during the course of plant growth. The chemicals found after analysing the waste ashes included some of the heavy metals that remained active after burning. These were left behind in the environment. Consequently, it was concluded that household solid waste disposal practices in rural areas should be reviewed urgently, as they affect plant growth negatively. Recommendations were provided. / Environmental Sciences / M. Sc. (Environmental Science)