Report (M.S.)--Virginia Polytechnic Institute and State University. M.S. 1993. / Vita. Abstract. Includes bibliographical references (leaves 53-54). Also available via the Internet.

Report (M.S.)--Virginia Polytechnic Institute and State University. M.S. 1991. / Vita. Abstract. Includes bibliographical references (leaves 75-76). Also available via the Internet.

More than 80 per cent of wastewater from human activities is discharged into the rivers or sea without any pollution removal, and the Sustainable Development Goals (SDGs) aim to halve this proportion and increase recycling and reuse globally by 2030. Treatment plants in Sub-Saharan Africa often fail due to lack of operating funds, poor regulation and poor design that does not take into account human factors. The failure of treatment plants can also be put down partly to the funding structures for management, which are often dependent on the disposal tariffs charged. Without sufficient regulation and enforcement, which is often lacking in Sub-Saharan Africa, this often leads to illegal disposal of faecal sludge. Due to the nutrient content and energy potential of wastewater, there is increasing focus on reuse of faecal sludge in ways that can contribute funds for maintenance and incentivise good management of treatment facilities. This research investigates potential designs for the re-use of faecal sludge in small cities in Sub-Saharan Africa to ensure proper treatment. Conducting two case studies using qualitative and quantitative methods, the research looks at the potential for re-use to be scaled up in Sunyani, Ghana and Mzuzu, Malawi, and whether different designs can ensure good management. Building upon the research investigation into how previous designs have failed in case studies, the research also investigates the use of agent-based modelling (ABM) as a modelling approach to explore social and technical aspects of sanitation systems to predict how different designs and management approaches can work. In Sunyani, biogas was the most acceptable option to customers whilst also providing a good business model to fund faecal sludge treatment, either as a decentralised system at public toilets where the fresh sludge is better for biogas production, or centrally at the existing disposal site. The success of biogas as a model that can fund maintenance and ensure good management would depend on the faecal sludge quality of public toilet sludge in the city and the investment level required and how any operating approach would work between the government and private sector. In Mzuzu, two main approaches to faecal sludge re-use exist currently: the implementation of Skyloos as above ground household toilets which provide compost, and a central disposal site from which compost is illegally harvested. At disposal, farmers remove sludge from the ponds and apply it untreated directly onto agricultural land. At times, private sector emptying services do not use the ponds, but also apply untreated sludge to agricultural land. Skyloos were found to have varying levels of success from different Non- Governmental Organisation (NGO) projects, with key sustainability issues being the availability of financing mechanisms, management between landlords and tenants and the trust of and engagement with implementing organisations. Existing approaches to waste management and re-use were found to be inaccessible and not working when implemented for the poorest and people with disabilities. Adopting re-use of faecal sludge in agriculture in Malawi would require improved marketing of sanitation options, financing options for households to incentivize adopting the technology, not targeting to poorest households and people with disabilities, and an improved management model for the treatment site to ensure safe disposal and production of compost. Looking at ABM as a way of modelling faecal sludge treatment systems in Sub- Saharan Africa, two models of different approaches in Mzuzu were developed to look at scaling up Skyloo toilets and managing the treatment plant. Both models demonstrate the potential of ABM to incorporate social and technical aspects into predicting the performance of different designs and approaches. The success and use of modelling depends on the quality of data that can be collected before implementing system approaches. Overall the thesis presents different models of treatment and re-use that can work and contribute to operating and maintenance of systems. It is unlikely that any design system will be so profitable that the treatment and re-use of sludge will be able to ensure good management without regulation, so the success of designs depends on relationships between the government and private sector and households in small cities.

<p>The systems engineering process has been applied to determine the feasibility of building a de-inking plant in Northern Virginia. This plant will recycle old newspapers and magazines into newsprint to be used by a local newspaper company in the production of their daily newspaper.</p> <p> A needs analysis establishes the local newspaper company's desire to obtain a reliable source of one-hundred percent recycled newsprint at a competitive cost. The analysis proposes building a de-inking plant to produce the required quantity and quality of recycled newsprint required to fulfill the local newspaper company's production needs. The analysis applies the engineering process to develop the system's high-level operational and maintenance requirements. This process establishes a system configuration used to evaluate the system's economic feasibility.</p> <p> The results of this analysis indicate that the de-inking plant system is feasible within the available technology and economic resources. The de-inking plant can provide a reliable source of 100% recycled paper at a cost that is below the present cost for similar recycled newsprint.</p> / Master of Science

<p>The systems engineering process has been applied to develop and evaluate a system that collects and processes scrapped catalytic converters to recover the platinum group metals retained by the converters' spent catalyst substrate.</p> <p> A needs analysis establishes a catalytic converter manufacturer's desire to reduce the cost of obtaining platinum group metals used to produce new catalytic converters. The analysis proposes a collection and processing system as an alternative to existing suppliers to provide these metals at a lower cost. The analysis applies the engineering process to develop the system's high-level requirements and devises its components, inter-relationships, and operation. This process establishes a system configuration used to evaluate the system's economic feasibility.</p> <p>The results of this analysis indicate that the collection and processing system is feasible within the constraints of available technology and economic resources.</p> / Master of Science

Dissolution of cellulose is an important but complicated step in biofuel production fromlignocellulosic materials. Steam and supercritical carbon dioxide (SC-CO2) explosion are two effective methods for dissolution of some lignocellulosic materials. Loading and explosion are the major processes of these methods. Studies of these processes were performed using grand canonical Monte Carlo and molecular dynamics simulations at different pressure/ temperature conditions on the crystalline structure of cellulose. The COMPASS force field was used for both methods.The validity of the COMPASS force field for these calculations was confirmed by comparingthe energies and structures obtained from this force field with first principles calculations.The structures that were studied are cellobiose (the repeat unit of cellulose), water–cellobiose, water-cellobiose pair and CO2-cellobiose pair systems. The first principles methods were preliminary based on B3LYP density functional theory with and without dispersion correction.A larger disruption of the cellulose crystal structure was seen during loading than that during the explosion process. This was seen by an increased separation of the cellulose chains from the centre of mass of the crystal during the initial stages of the loading, especially for chains in the outer shell of the crystalline structure. The ends of the cellulose crystal showed largerdisruption than the central core; this leads to increasing susceptibility to enzymatic attack in these end regions. There was also change from the syn to the anti torsion angle conformations during steam explosion, especially for chains in the outer cellulose shell. Increasing the temperature increased the disruption of the crystalline structure during loading and explosion. / Akademisk avhandling som för avläggande av teknologie doktorsexamen vid Chalmers tekniska högskola försvaras vid offentlig disputation den 10 oktober 2014,klockan 13.00 i KS101-salen, Kemigården 4, Göteborg.

Renewed momentum in the microalgae industry due to commercial interest in biofuels and bioproducts is driving the need to increase the economic competitiveness of large-scale microalgal production. Current knowledge of membrane systems common in other disciplines, such as environmental engineering, marine science, and biomedicine, are relevant to algae production. With pore sizes ranging from microns to angstroms, membranes provide tailored functions for solid/liquid separation (cell retention, biomass concentration and dewatering), gas/liquid separation (gas delivery and removal), and solute/liquid separation (bioproduct recovery, feedstock preparation and effluent recycling) that are problematic or not possible with other technologies. Though membranes have great potential to facilitate cultivation and harvesting, challenges in energy reduction and fouling mitigation need to be overcome for long-term, cost-effective applications. This body of research includes a thorough literature review of membrane applications in the algal industry and three experimental studies investigating ways to improve the cultivation and harvesting of microalgal species in wastewater. The first study investigated the growth of native and augmented algal communities in various growth media. Algal monocultures (Chlorella sorokiniana and Botryococcus braunii) and algal communities native to clarifiers of a wastewater treatment plant were batch cultivated in 1) clarified effluent following a BOD removal reactor (PBCE), 2) clarified effluent following a nitrification reactor (PNCE), and 3) a reference medium (RM). After 12 days, all algal species achieved nitrogen removal between 68-82% in PBCE and 37-99% in PNCE, and phosphorus removal between 91-100% in PBCE and 60-100% in PNCE. The pH of the wastewater samples increased above 9.8 after cultivation of each species, which likely aided ammonia volatilization and phosphorous adsorption. Both monocultures grew readily with wastewater as a feedstock, but B. braunii experienced significant crowding from endemic fauna. In most cases, native algal species' nutrient removal efficiency was competitive with augmented algal monocultures, and in some cases achieved a higher biomass yield, demonstrating the potential to utilize native species for nutrient polishing and algal biomass production. In the second study, the isolated cultivation of algal resource utilizing selectivity (ICARUS) process was conceived and developed. ICARUS integrates a passive membrane photobioreactor configuration with wastewater as a growth medium. Eleven membranes of varying porosity and materials were examined based on characteristics and resulting algae productivity. Four ICARUS series (40kDa-PVDF, 0.53 g L-1, 14.1 mg; 0.1µm-PVDF, 0.43 g L-1, 16.6 mg; 12kDa-RC, 0.35 g L-1, 14.5 mg; 0.2 µm-CA, 0.41 g L-1, 14.5 mg) had a final cell density and mass yield that was significantly higher than that of suspended culture (0.25 g L-1, 9.1 mg). Optimal pore size range was identified to be 50-1000 kDa. Six additional series (0.2µm-CA, 0.1µm-PVDF, 40kDa-PVDF, 12kDa-RC, 3.5kDa-PVDF, and 3kDa-RC) also sustained significantly longer exponential growth phases than the suspended cultures. The ICARUS series maintained an average pH of 9.55, which was significantly lower than the average pH of 10.21in the suspended culture. Membrane characteristics affecting the variability in microalgae productivity were evaluated in 2D and generalized linear models. In the third study, select membranes from the laboratory experiments in Chapter 5 (12kDa-RC, 40kDa-PVDF, 7µm-NY) were tested in extended field conditions at a wastewater treatment plant, where the movement of dissolved constituents and biomass productivity were compared to that of closed suspended series. All ICARUS series had higher biomass productivity (RC, 2.87 g L-1; PVDF, 10.6 g L-1; NY, 8.45 g L-1) than the suspended series (0.38 g L-1), which was due to both a longer exponential growth phase and passive dewatering in the ICARUS series. Dissolved ions passed readily across each membrane, and no nutrient limitation was apparent in any series. Gas exchange was slower than expected, which may have been due to external and internal attached growth utilizing gases at the membrane surface. However, dissolved oxygen concentration did not limit algal growth, and adequate carbon dioxide was available to regulate ICARUS pH. In fact, the ICARUS series maintained an average pH of 7.6, whereas the pH of the control series reached 9.8-10.5. The invasion of endemic wastewater species was dependent on pore size; the RC and PVDF series maintained a monoculture, but the NY series had severe contamination. The resulting research has demonstrated a proof-of-concept of a new microalgal cultivation method which may reduce the cost of large-scale cultivation efforts integrated at wastewater treatment plants or within existing algal production facilities. Investigating various wastewater effluents, membranes, and algal strains has allowed for recommendations for the operation of scaled-up systems. Future research should focus on mechanisms and characteristics of biofouling as well as the operation of a field scale prototype. By improving large scale algal cultivation, algal biofuels may become more economically competitive with fossil fuels or other renewables, enhancing their participation in the country's diverse energy portfolio.

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.

Abstract The thesis mainly deals with the analysis of the structure and organization of the informal plastic andmetal recovery system in Accra. To give a clear picture of the context within which the informal wasterecovery system exists, the study has examined the existing formal solid waste management system inAccra. To this end, the study employed a case study method using both qualitative and quantitativeapproaches to solicit the necessary data during the two months of field work in Accra. Furthermore, thethesis employs concepts and theories such as network theory, actors-oriented approach and wastemanagement theories to look in to the structure and organization of the informal plastic and metalrecovery system from a new perspective.As a result, this thesis has revealed that the informal recovery system is built out of social ties and a widerange of reciprocity networks. These networks are of small in size with small number of membership;however, interconnected to one another. In most cases, the network members have common features suchas gender, religious affiliation, place of origin and reasons to join the informal plastic and metal recoverysystem. These networks also have an organizational structure that shows the institutionalization of rolesand responsibilities. This has further provided the structure and condition for the development andstrengthening of common values and norms. These norms and values are more or less providing a senseof control and governance for the networks and their activities. In addition, these networks also provide asocial security system for its members in case of emergencies.The study has also revealed that the identified actors within the recovery system are organized in the formof trade hierarchy where the income and profit of the actors depends on their position within the tradehierarchy. In addition, the ability to add value and also being at the end of the trade chain has a positiveimpact on the amount of income or the profit margins of the actors. In addition, actors placed at theupper- most end are sources capital and finance to the recovery system.Despite the fact that the informal plastic and metal recovery system functions in parallel and interactswith members of the formal waste management sector, the system is ignored by the government. Theinformal recovery system is not considered as a major stakeholder for solid waste management sector.Moreover, the formal sector is also creating a challenge for the existence of the informal sector. There is aneed to integrate the informal recovery system in to the formal system as the activities of recoveringplastics and metals are significant for the environment in particular and for sustainable development ingeneral. / IWWA - Integrated Waste Management in West Africa

Electr(on)ic equipments possess parts and components with high economic value and environmental peril which prompts a potential need to assess the EEE’s management at EoL. E-waste management in developing countries is one of the least revised environmental topics. In recent times however the subject is getting research limelight from scholars. This study aims at enhancing the existing e-waste management practice in Gaborone, Botswana through systematic investigation of the current circulation, usage, handling and management of W(EEEs). Several stakeholders in the solid waste management system were interviewed and also an in situ (on the landfill) waste composition study was conducted in line with the aims and objectives of the research. The study finds that WEEEs do not have exclusively designed management structure in Gaborone and they rather flow source to sink usually blended with the general waste derived from the entire socio-economic activity. Waste composition study conducted on the landfill indicates a very low percentage composition (less than 1%) of WEEEs in the junk corresponding to 1.9 kg/capita/year. Substantial amount of obsolete EEEs rather seem to linger in the socio-economic system until a capable tapping mechanism is installed. An integrated e-waste management system cored around public sensitisation and the novel phenomenon of Enhanced landfill mining which simultaneously offers time to consult developed countries for expertise on sustainable WEEE management is proposed. The impetus to close the linear flow of electr(on)ic materials remain with the government and a range of stakeholders/interest groups who seek to gain economic advantages and also trim down environmental implications from the circulating and landfilled W(EEEs).