Thesis (M. Sc.)--University of Hong Kong, 2001. / Includes bibliographical references (leaves 84-93).

Thesis (M. Sc.)--University of Hong Kong, 2002. / Includes bibliographical references.

Dyes are often recalcitrant organic molecules that produce a colour change and contribute to the organic load and toxicity of textile industrial wastewater. Untreated effluent from such sources is harmful to aquatic life in the rivers and lakes due to reduced light penetration and the presence of highly toxic metal complex dyes. The use of alum as flocculant/coagulant in wastewater treatment is not encouraged as it induces Alzheimer’s disease in humans and results in the production of large amounts of sludge. Therefore, the development of safe and biodegradable flocculating agents that will minimize environmental and health risks may be considered as an important issue in wastewater treatment. Bioflocculants are extracellular polymers synthesized by living cells. In this study, bacterial bioflocculants were assessed for their ability to remove dyes from textile wastewater as well as reducing the microbial load in untreated river water. The bacteria were isolated from a wastewater treatment plant and identified using standard biochemical tests as well as the analysis of their 16S rDNA gene sequences. Six bacterial isolates were identified viz. Staphylococcus aureus, Pseudomonas plecoglossicida, Pseudomonas pseudoalcaligenes, Exiguobacterium acetylicum, Bacillus subtilis, and Klebsiella terrigena. The flocculating activities of the bioflocculants produced by these isolates were characterized. The effect of temperature, pH, cations and bioflocculant concentration on the removal of dyes, kaolin clay and microbial load was also determined. The amount of bioflocculants produced by the bacterial isolates ranged between 5 and 27.66 g/l. According to the findings of the present study, bacterial bioflocculants were composed of carbohydrates, proteins, uronic acid, and hexosamine in varying quantities. The bioflocculants were effective to varying degrees in removing the dyes in aqueous solution, in particular whale dye, medi-blue, fawn dye and mixed dyes, with a decolourization efficiency ranging between 20-99.9%. Decolourization efficiency was influenced by the bioflocculant concentration, pH, temperature, and cations. The bacterial bioflocculants were also capable of reducing both the kaolin clay and the microbial load from river water. The flocculating activity ranged between 2.395–3.709 OD-1 while up to 70.84% of kaolin clay and 99% of the microbial load from the river water was removed. The efficiency of kaolin clay flocculation increased with higher concentration of bacterial bioflocculants. The optimum pH for the flocculating activity was observed between 6 and 9. The best flocculating activity was observed at 28oC. Divalent cations such as Mg2+ and Mn2+ improved the flocculation while salts such as K2HPO4, CH2COONa, and Na2CO3 did not. The findings of this study strongly suggest that microbial bioflocculants could provide a promising alternative to replace or supplement the physical and chemical treatment processes of river water and textile industry effluent. / Thesis (M.Sc.)-University of KwaZulu-Natal, Durban, 2008.

This thesis concerns waste management on construction sites and was conducted on behalf of ICA Fastigheter. Areas of concern: How can an environmentally-efficient waste management system on construction sites be defined?  What potential exists for exploiting the waste resources that are generated? How can the waste management be optimised by reducing the quantity of waste and by optimal sorting? How can the client of a project influence the waste management? The purpose of the work was to investigate sustainable waste management in the building and construction sector and to highlight waste as a resource from an environmental and economic perspective.The aim of the work was to define an environmentally-efficient waste management system, to analyse the potential that exists in waste management and to draw up guidelines for optimal waste management.The method consisted of a literature study, two visits to construction sites and four interviews.An environmentally-efficient waste management system means that the waste is managed in the following order of priority: Prevention      Reuse   Recycling      Energy recovery Landfill      The prevention of waste is an important area that has not been adequately explored by the building and construction industry. The quantities of waste could decrease with the implementation of measures such as ordering materials in the dimensions required, prefabricated components, logistics centres with Just-In-Time deliveries, less and improved packaging and less wrapping. The reuse of waste materials and temporary apparatus as well as the use of a return pallet system are examples of reuse that reduces the quantities of waste. In most cases the source sorting work is a matter of course and the proportion going to landfill is down at a low level. The source sorting can be optimised by sorting all materials that can be reused and recycled to use them as a resource. The client of a project has great opportunities to influence the waste management in a sustainable direction by placing demands on the contractor. Demands can be placed on measures to reduce the quantities of waste, on a specific level of source sorting and on the reporting and monitoring of statistics.

In present day society there is an artificial dichotomy between wastes and resources that is perhaps best summed up by the Western Sydney Waste Board slogan 'there is no such thing as waste � only resources in the wrong place and at the wrong time'. Waste management was originally driven by managing the health consequences of wrong time/place materials. This has changed and the significant driver is now the sustainable utilisation of resources, that is, trying to optimally recover as resources (right time/place) those materials that present as wastes requiring management. However, it is not acceptable to justify a resource recovery option purely on the basis that it is diverting material away from landfill. Preferences are emerging for recovery activities that maximise the resource value of a material according to techno-economic, environmental and socio-political criteria; collectively known as the criteria of sustainability. The people and organisations articulating these preferences include owners/operators of resource recovery centres, proponents of alternative waste management technologies, waste planners and managers at both a state and local government level and environmental NGOs representing community interests, in addition to the generators of waste at a domestic, commercial and industrial, and construction and demolition level. It is therefore important to be able to answer the question of 'what is the optimal or most sustainable resource recovery option for materials presenting as waste to landfill in the Greater Sydney Region?' The point of departure for this thesis is twofold. Firstly, that optimal resource recovery options (also known as alternative waste management technologies) can be identified by understanding the context and system drivers and constraints within the system of waste generation and utilisation, by modelling the system using industrial ecology (specifically Materials Flux Analysis) and by using the technology assessment framework developed by the NSW Alternative Waste Management Technologies and Practices Inquiry to evaluate the available options. Secondly, that should the assessment framework from the NSW Inquiry prove to be unsuitable as a framework for evaluation, then an improved and refined assessment framework can be constructed in order to identify optimal resource recovery options and that this process can be successfully demonstrated using wood waste as a case study. The context of waste as an issue has shifted from local government control (pre-1970s) to state government control through the Department of Environment and Conservation. This transition followed experiments with organisations such as the NSW Waste Boards and Resource NSW, in addition to state targets such as a 60% reduction of waste to landfill by the year 2000. In addition to this backdrop of change from a government administrative perspective, there are also a suite of often conflicting drivers and constraints influencing the process of resource recovery. For example, sustainable development is a public policy driver for the integration of environmental and societal concerns, but can also constrain new innovation if competing 'status quo' utilisation options are not subject to the same scrutiny. Similarly, legislation acts as a constraint to resource recovery options by establishing license conditions, prohibiting some energy recovery options and setting recovery criteria; however legislation also acts as a driver for resource recovery options that generate renewable electricity or act to reduce greenhouse gas emissions. Other drivers and constraints include social, technical and economic issues and concerns in addition to environmental impacts such as emissions to air, land and water. Industrial ecology is a model for viewing system components as part of a dependent and interrelated greater whole. Within the context of Industrial Ecology, waste is a by-product of manufacture available as a beneficial input into other processes. Using Materials Flux Analysis as a tool to build a model of waste generation and utilisation, elements within the system are presented as a series of stocks (sources), technology interventions (transformation flows) and sinks (markets). The stocks or sources of materials for resource recovery are categorised as Municipal Solid (MSW), Commercial and Industrial (C&I) or Construction and Demolition (C&D) wastes. Approximately seven million tonnes of waste is generated in the Greater Sydney Region (nearly two and a half million tonnes of materials recovered for recycling and four and a half million tonnes of materials disposed of to landfill). The purpose of technology intervention is to transform the material into a product that is suited to the end market (sink). Markets are grouped according to reuse (same function and form), direct recycling (same supply chain), indirect recycling (different supply chain) and energy recovery (either as process heat, electricity or co-generation, a combination of the two). Landfill is also a potential sink for materials and in this sense can be thought of as a negative value market. The Alternative Waste Management Technologies and Practices Inquiry provided an assessment framework for resource recovery technologies. Each technology was measured and compared against 16 evaluation criteria, resulting in a score out of one hundred. Material sorting scored the highest (81.5), incineration the lowest (50.8) with most of the biological technologies performing �well� (64.6 � 71.7) and with the landfill technologies performing 'moderately well' (60.4 - 61.4). The positive features of the Inquiry included the overview of alternative resource recovery technologies, waste generation and other issues pertinent to decision making and resource recovery. The negatives of the Inquiry arise from the inadequacies of the assessment framework, which lacked technology options, system boundary definition and requisite evaluation criteria in addition to inconsistencies in scoring approaches. By undertaking a sensitivity analysis on the Inquiry�s results, it is shown that rank order reversal results from the allocation of weightings. The improved and refined assessment framework, constructed to overcome identified inadequacies of the Inquiry�s approach, focussed on clearly identifying the problem to be addressed and the primary decision maker involved in the process; ensuring that appropriate options for evaluation were included; defining the system boundary for the assessment; selecting necessary evaluation criteria; adopting a more sophisticated system for scoring; and using a sensitivity analysis to validate the results of the resource recovery option evaluation. Wood waste was used as a case study for this second assessment methodology. Wood waste refers to the end-of-life products, failed products, offcuts, shavings and sawdust from all timber products. Approximately 350,000 tonnes of wood waste are disposed of to landfill each year. This comprises untreated timber (hard wood and soft wood), engineered timber products (particleboard, medium density fibreboard and plywood) and treated timber (predominately copper chrome arsenic). Eight wood resource recovery options are selected for evaluation within the Greater Sydney Region with a different approach to scoring that has the advantage of 'scaling up' the best performers within each attribute (highest score) while 'scaling down' the worst performers (no score). Under this evaluation, an on-site purpose built energy facility is the most preferred option with particleboard manufacture the least preferred option. A sensitivity analysis of the results reveals that the scores of each technology option are sensitive to the weightings of the decision maker. When the change in rankings is examined, it is identified that two eight wood recovery options undergo a large rank reversal. A critique of the results of the wood evaluation reveals five major flaws. Firstly the evaluation produces non-highest resource value results that are non-intuitive (and arguably misleading), for example the poor performance of reuse and particleboard against energy generation options. Secondly, the recording of a single summary score for each recovery option hides unacceptable performance levels in some criteria. For example, the top scorer of Primary Energy On-site hides the fact that such an option is likely to have no political desirability (likely public opposition to 'incineration' within the Sydney air-shed), calling into question its ability to be implemented as a solution. Thirdly there is a reliance on judgement for the scoring of options and weighting of preferences, calling into doubt the accuracy of scores. Fourthly, the rankings of recovery options by the assessment framework are sensitive to the allocation of weightings. Finally and most importantly, the refined evaluation approach suffers from the 'discrete option syndrome', the scoring of each recovery option in isolation with no ability to look at integrated systems with joint recovery options. This is pinpointed as a fundamental flaw in the process of both the Inquiry and the wood evaluation. This leads to the conclusion that the founding assertions of this thesis were false. That is to say that the assessment framework developed by the NSW Alternative Waste Management Technologies and Practices Inquiry is not suitable for use in evaluating resource recovery options. Furthermore a refined assessment framework based on this approach is also unable to identify optimal resource recovery options as demonstrated using wood waste as a case study. The results of this research points to the overall conclusion that any discrete option evaluation and assessment for resource recovery technologies that results in a single summary score for each option will be fundamentally flawed, providing no value in determining optimal resource recovery solutions for the Greater Sydney Region. A systems approach is suggested as an alternative method for the evaluation of optimal resource recovery, the starting point of which is to ask 'what is the highest resource value of the components in the material stream under consideration and how could a network of infrastructure be designed in order to allow materials to flow to their highest resource value use?' A feature of such an integrated approach is a focus on the materials composition of recovered resources, as opposed to recovery technologies, resulting in a 'fit for purpose' as opposed to a 'forced fit' style of resource recovery. It is recommended that further research and public policy efforts be made in logistics planning across the Greater Sydney Region (as opposed to a regional or local government area) in order to create network opportunities for integrated flows of materials to move toward their highest resource value.

Thesis (M.Hous.Man.)--University of Hong Kong, 2009. / Includes bibliographical references (p. 90-97).

Abstract In an attempt to construct a new agenda for waste management, this thesis explores the importance of the definition of waste and its impact on waste management, and the role of ownership in waste management. It is recognised that present legal waste definitions are ambiguous and do not really give an insight into the concept of waste. Moreover, despite its explicit wish of waste prevention, when according to present legislation a thing is assigned the label of a waste, it is going to be treated like waste, implicitly legislation thus amasses waste. The philosophical ramifications inherent in such definitions mean that they are not capable of constructing a system that, by its very nature, results in a sustainable waste management system. It is also a fact that, while there are numerous practices as to how to deal with a particular type of waste, there is no theory of waste management. In this thesis, waste as a concept is analysed from the point of view of why and when waste is created. Using the PSSP language, waste is classified based on the Purpose and Performance attributes. New, dynamic definitions for waste and waste management are offered, which explain why waste is created and intrinsically offer a solution to how the problem could be solved. Additional waste-related concepts are introduced, which are thought to have great potential for improvement on waste regulation. The concept of ownership is explained as rights and responsibilities of waste creators/owners: it is thus crucial to raising awareness about waste. Ownership in itself often dictates which waste management options are preferentially adopted by a given community. The role of legislation in producing monitoring systems for the transfer of ownership as well as abandonment of ownership is analysed. To avoid obstacles to resource conservation due to materials being considered waste, a definition for non-waste is introduced. The new agenda for waste management thus focuses upon the development of more appropriate, sustainable definitions so that what is now commonly perceived as being waste will in fact be increasingly seen as resource-rich, 'non-waste'. The role of waste management is explained as control of all waste-related activities, with the aim of preventing, minimising or utilising waste. The need for a theory of waste management is explained, and the first building blocks of the theory are proposed. This thesis is offered as the first step toward scientification of waste management.

This diploma thesis concentrates on the waste disposal in Třinec. The first chapter of the thesis is focused on the theoretical mooring of the waste disposal issue, both on the basis of the valid legal legislation, and the basis of the literature. The second chapter already concentrates on the area of the Třinec waste management itself. It describes the functioning of the waste management system, informs about the aims of the Waste Management Plan and evaluates their continuous fulfilment. Then it acquaints with the waste disposal of both the corporations and the individuals, and it also names the establishments competent to dispose with the waste, situated in the area of theTřinec town. Further, the thesis analyzes the waste evidence system of the corporations and the individuals authorized to the business, describes the weak points of this evidence and proposes to the necessary solutions. Hereinafter, the thesis focuses on the weak points of the waste management system funding, and also suggests the possible solutions on the basis of the valid legislation.

No description available.

Waste is anything which is considered to be no longer useful to anyone. In reality, it actually possesses the ability to be the raw material for several other processes and applications. Improper handling of wastes could result in several environmental hazards such as air pollution, soil erosion, methane emissions, low birth rate and others. In developing countries, proper handling of wastes is one of the important topics to be focussed from an environmental perspective. This thesis aims to propose an improved waste collection system in Gaborone through investigating the current waste management practices in Gaborone from different perspectives. Several stakeholders were interviewed for gathering information related to the present waste legislations, waste collection, treatment, and disposal methods. A composition study was also conducted along with the other research teams in order to support the objective of this thesis. The results shows that the current waste management practices has certain flaws which the management has to overcome in order to avoid the environmental impacts caused by the waste generation in Gaborone. Basic Recycling and treatment facilities are absent in Gaborone. The local government do not have any updated plans for the proper handling of wastes. The obtained results are critically analysed to showcase the existing flaws in the waste management practices, and using the state of the art knowledge in waste management the research team suggests an improved waste collection system for Gaborone considering the economic and environmental conditions.