Thesis (MEng)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: Concerns surrounding the world’s current dependence on quickly depleting fossil fuels and their negative environmental impacts have brought about much research into renewable and sustainable energy sources. With population and economic growth not only is this dependence increasing but there is an increasing production of waste by society in general. With space becoming a premium commodity and environmental protection a necessity, landfilling of the majority of the world’s waste is no longer feasible. Thus, research is being carried out into waste-to-energy (WTE) processes and refuse derived fuels (RDF). This study focuses on thermochemical conversion, specifically pyrolysis of solid wastes as a means of energy product recovery. Before a specific waste stream can be used in WTE or RDF contexts its composition and degradation behaviour needs to be investigated. For this reason, a full physical characterisation of the municipal solid waste (MSW) from the Stellenbosch municipality was carried out. It was found that the composition of waste differs between areas within the municipality but the composition of the waste in general compares well with international data. It was found that six main components present in the recyclables stream; namely high and low density polyethylene (HD/LDPE), poly(ethylene terephthalate) (PET), glossy paper, office paper and newspaper would be suitable for thermochemical conversion. The thermal properties and pyrolytic degradation of these six components were investigated by multi heating rate thermogravimetric analysis (TGA) from which kinetic parameters (activation energy, pre-exponential factor and kinetic rate constants) were calculated by a differential isoconversional method. The volatiles released during degradation were identified by way of online mass spectrometry (TGA-MS) yielding six individual kinetic schemes. In order to gauge to what extent milligram pyrolytic experimentation (TGA-MS) can be used to predict larger scale pyrolytic behaviour, runs were performed on one plastic (HDPE) and one paper (glossy paper) sample on a gram scale pyrolytic plant under both slow and vacuum conditions. It was found that, especially for high thermal conductivity samples, yields on gram scale experimentation can be accurately predicted on a milligram scale. Further, the compositions of slow pyrolysis oils from glossy paper, obtained by gas chromatography–mass spectrometry (GC-MS), were compared to TGA-MS results as well as off gases captured from TGA runs by thermal desorption (TGA/TD-GC-MS). It was found that TGA-MS and TGA/TD-GC-MS can be used to predict the main functional groups in pyrolysis oil produced on a gram scale. Thus small scale experimentation can be used to determine the suitability of different waste components for pyrolytic conversion. / AFRIKAANSE OPSOMMING: Kommer oor die wêreld se huidige afhanklikheid van fossielbrandstowwe en die negatiewe uitwerking op die omgewing het baie navorsing oor hernubare en volhoubare energie bronne meegebring. Bevolking en ekonomiese groei veroorsaak 'n toename in hierdie afhanklikheid en in die produksie van afval deur die samelewing. Daar is baie min onbenutte grond oop en die beskerming van die omgewing het noodsaaklik geword. Dus is storting van die meeste van die wêreld se afval nie meer ‘n aanvaarbare opsie nie. As gevolg daarvan word daar tans navorsing in afval-tot-energie (ATE) prosesse en afval afgeleide brandstowwe (AAB) gedoen. Hierdie studie fokus op die termochemiese omskakeling van afval, spesifiek pirolise, as 'n methode vir energie-produk hernuwing. Voordat 'n spesifieke afvalstroom gebruik kan word as 'n AAB moet die samestelling en afbrekings gedrag eers ondersoek word. Daarom is 'n volledige fisiese karakterisering van die munisipale afval (MA) van Stellenbosch munisipaliteit uitgevoer. Resultate het getoon dat daar ‘n verskil in die samestelling van afval tussen die gebiede binne die munisipaliteit is. Afgesien daarvan vergelyk die samestelling van die afval in die algemeen goed met internasionale data. Daar is gevind dat daar ses belangrike komponente teenwoordig is in die herwinbare stroom wat geskik sou wees vir termochemiese omskakeling, naamlik; hoë en lae digtheid poliëtileen (HD/LDPE), poli(etileen tereftelaat) (PET), glans, kantoor en koerant papier. Die termiese eienskappe en termiese afbreking van hierdie ses komponente is ondersoek deur middel van multi-verhittimgs tempo termogravimetriese analise (TGA) waaruit kinetiese parameters (aktiveringsenergie, pre-eksponensiële faktor en kinetiese snelheidskonstantes) deur 'n differensiële omskakelings metode bereken is. Die vlugtige komponente wat tydens die afbreking vrygestel is, is geïdentifiseer deur aanlyn-massaspektrometrie (TGA-MS) wat ses individuele kinetiese skemas verskaf. Om vas te stel tot watter mate milligram pirolitiese eksperimente (TGA-MS) gebruik kan word om op ‘n groter skaal die pirolitiese gedrag te kan voorspel, is eksperimentele lopies op een plastiek- (HDPE) en een papier (glans papier) monster op 'n laboratorium skaal pirolise opstelling onder stadige- en vakuum omstandighede uitgevoer. Daar is gevind dat, veral met hoë hitte geleiding komponente, die opbrengs op gram skaal eksperimente akkuraat voorspel kan word op ‘n milligram skaal. Verder was die samestelling van die stadige pirolise olies uit glans papier, wat verkry word deur gaschromatografie-massaspektrometrie (GC-MS), vergelyk met TGA-MS resultate sowel as af-gasse gevang van TGA lopies deur termiese desorpsie (TGA/TD-GC –MS). Daar is gevind dat TGA-MS en TGA/TD-GC-MS gebruik kan word om die belangrikste funksionele groepe in pirolise olie, wat op 'n gram skaal geproduseer word, te voorspel. Dus kan milligram eksperimente gebruik word om die geskiktheid van afval komponente vir pirolitiese omskakeling te bepaal.

Thesis (MDF)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: Johannesburg generates in excess of 1 500 000 tonnes of general waste annually and has on average 10 years’ lifespan remaining on its four landfill sites. As a signatory to the Polokwane Declaration, the City of Johannesburg has recognised the need for new interventions to divert waste from landfills by various methods, such as separation at source; alternative treatment methods and the conversion of waste to energy. Progress has, however, been slow and this research aims to investigate alternative waste management techniques that can be applied in the City of Johannesburg to fast track the realisation of these targets. Using scenario planning techniques, the research considers implications for policy and management decisions in realising the best possible future in the area of waste management in Johannesburg. The scenario process was used to develop the following scenarios for waste management in Johannesburg: Long walk to freedom. Waste collection coverage includes pockets of the community where waste collections services are less than optimal. The residents of the city, particularly in these underserviced areas, are also not very knowledgeable of the impact that the waste generated within their communities can have on the environment and what alternatives there are to manage this. Pick it up. The City provides full services to a society that functions in relative oblivion of the implications of their behaviour on the environment. It is assumed to be the role of government to “pick up” after communities and dispose of waste. This scenario is oblivious of the waste hierarchy and the role communities could play in minimising waste. Wishing on a star. The city continues to have under-serviced areas, public awareness is high and this fuels correct behaviour and a mind-set shift with regard to waste management. Working together we can do more. The City optimises its service provision to cover all areas while also ensuring maximum public awareness and behaviour change with regard to waste management.

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

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

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

Thesis (Masters of Environmental Health)--Cape Peninsula University of Technology, 2018. / In the Western Cape, South Africa and other regions globally, grape pomace (GP) is one of the abundant agro-waste from the winery industry. This study reports on the hyper-extraction of fermentable sugars from GP treated with white rot fungi (WRF) Phanerochaete chrysosporium BKMF 1767 to facilitate improved biovalorisation for total reducing sugars (TRS) extraction in conjunction with Nepenthes mirabilis digestive fluids. TRS were quantified using the 3,5-dinitrosalicylic acid (DNS) reagent method. The free readily dissolvable sugars from the GP recorded for the bio-treated (BT) samples was 206.39 ± 0.06 mg/L and for the untreated (UT) samples was 271.05 ± 0.02 mg/L. Overall, the TRS yield for the Bio-treated (BT) and untreated (UT) samples was recorded as 205.68 ± 0.09 and 380.93 ± 0.14 mg/L, respectively, using hot water pretreatment (HWP) with 2266.00 ± 0.73 (BT) and 2850.68 ± 0.31 mg/L (UT), respectively, for dilute acid pretreatment (DAP); with 2068.49 ± 6.02 (BT) and 2969.61 ± 8.054 mg/L (UT) respectively, using the cellulase pretreatment (CP) method. Using the HWP as a reference, the relative increases imparted by the biotreatment was higher (51%) for DAP and low (33%) for CP. The combination of conventional used pre-treatment methods (hot water pretreatment, dilute acid pre-treatment, and cellulase pre-treatment) in a single pot system was also done while monitoring the total residual phenolics (TRPCs) in the samples. Furthermore, powder X-ray diffraction (pXRD) were used to measure the crystallinity index (CrI) and functional groups of pre- and post-pretreated GP to ascertain the efficiency of the pre-treatment methods, with quantification of lignin, holocellulose, and ash. Overall, the TRS yield for N. mirabilis pre-treated agro-waste was 951 mg/L ± 4.666 mg/L, with biomass having a lower CrI of 33%, and 62% residual lignin content. Furthermore, reduced TRPCs were observed in hydrolysate, suggesting limited inhibitory by-product formation during N. mirabilis pre-treatment

A key dimension to improving urban economic and environmental sustainability is the efficient use of resources through recycling. A thriving recycling system requires not only effective institutional policies and community-wide diversion efforts, but also a competent local and regional recycling industry. Although the recycling industry has traditionally been recognized as a local service and fringe industry, it has noticeably transformed into an integral segment of industrial production systems as manufacturers have increasingly begun to adopt the principle of extended producer responsibility. Despite such changes, urban and regional theory and planning research has largely disregarded the industrial aspect of recycling, contributing to the dearth of information about the organizational and spatial patterns of the recycling industry and the impact of the establishment of recycling systems on local and regional scales. Given the knowledge gap, this dissertation addresses two questions: 1) What is the logic of the industry organization and spatial pattern of recycling industry in different institutional contexts? and 2) How is the economic and environmental impact of recycling systems determined in cases of construction and demolition waste recycling and waste carpet recycling? To answer the first question, this research develops a theoretical model that explains how recycling industrial activities are spatially distributed in light of institutional and organizational theories. The theoretical model characterizes organizational decisions pertaining to recycling functions and suggests spatial patterns of recycling systems. With respect to the second question, this research constructs a regional environmental input-output model on the metropolitan scale. It estimates regionalized energy use coefficients and greenhouse gas emission coefficients using various sources of data mainly compiled from the Manufacturing Energy Consumption Survey 2006, the State Energy Consumption Estimates, and the Commodity Flow Survey 2007. Based on regional input-output tables coupled with the regionalized environmental coefficients, this research quantifies, through simulations, the net economic and environmental impact of a localized construction and demolition waste recycling system in the San Francisco metropolitan area and regional carpet recycling systems in the Atlanta and Seattle metropolitan areas. Results of the simulations reveal that 1) the localized construction and demolition waste recycling system provides moderate economic benefits because of the limited job creation potential of mechanized recycling processes and yields relatively small environmental benefits with respect to the total weight processed; 2) wider adoption of the deconstruction technique expands job opportunities, increases energy savings, and reduces greenhouse gas emissions during the course of construction and demolition waste recycling; 3) regional-scale waste carpet recycling systems, in particular recycled nylon 6 production, create sizable new job opportunities and provides environmental benefits of energy savings and greenhouse gas emission reduction despite the long-distance transportation of waste carpet. These results suggest that policies that promote recycling industrial activities can significantly contribute to the economic and environmental sustainability of metropolitan areas.

University of Macau / Faculty of Science and Technology / Department of Civil and Environmental Engineering

The construction and demolition (C and D) recycling industry creates economic opportunity through business activity; promotes equity through workforce training and partnerships; and helps to conserve natural resources through the reuse, remanufacturing, and recycling of C and D debris. While C and D recycling satisfies traditional local economic development goals, it also addresses broader goals of progressive, and sustainable local economic development. The general planning literature shows an increasing interest in sustainability; however, there have been fewer studies on sustainable local economic development initiatives. This research examines the current state of local economic development agency support for the C and D recycling industry as an economic development strategy. In doing so, the dissertation assembles the array of activities local economic development agencies used to support the industry; identifies distinguishing policy or contextual characteristics of agencies that actively supported the industry from those that did not; and assesses whether the agencies support for C and D recycling fit within the rational planning model. Using data from a national survey of local economic development agencies, the study categorizes the local economic development tools used to support the industry. Results show that a combination of traditional, progressive, and sustainable local economic development tools are adapted and newly created to satisfy the specific needs of this specialized industry. Multiple discriminant analyses identify key characteristics of the agencies that support C and D recycling. These characteristics include previous support for the general recycling industry, the presence and support of environmental enterprise zones and eco-industrial parks, and knowledge of local landfill capacity issues. Overall, the agencies that actively supported C and D recycling engage in activities associated with sustainable local economic development. The descriptive and statistical analyses are combined with the surveys qualitative responses to determine that local economic development agencies do not operate under a strict interpretation of the comprehensive rational planning model in their support of C and D recycling. Instead, local economic development agencies use modified rational and reactive planning strategies in their support of the industry. The study concludes with policy recommendations to increase local economic development agency support for C and D recycling.

Waste management is one of the key issues of sustainable development. In Hong Kong, there is food waste management measures but it seems that they have a fair share of limitations. The amount of food waste disposed rose from 3,154 tons in 2005 to 3,237 tons in 2010, which has not shown a significant reduction in volume in recent years. Businesses are becoming more aware of their corporate social responsibility and they definitely have a role to play in sustainable food waste management. Food waste management requires a large amount of resource input and infrastructural support, therefore a collaborative network between the government, businesses and social organizations will surely allows for better performance. The Food Waste Recycling Partnership Scheme (FWRPS) is chosen to be the subject of this case study. It is a partnership program aiming to tackle the food waste problem in Hong Kong’s private sector. A total of 18 companies are chosen as case subjects for the study and are divided into three groups: 1) the participants of the FWRPS; 2) the non-participants of the FWRPS but with self-initiatives for food waste management and 3) the companies without much food waste management initiatives. The three groups are then compared and contrasted upon the drivers, barriers to food waste management and the role of the FWRPS towards effective food waste management. Major factors are drawn from the study such as corporate leadership and resource availability. It is found that those driving and hindering factors varies as companies adopt different food waste management options. In creating these differences, the FWRPS also plays an important role. The scheme succeeded in facilitating food waste management in the private sector as it allows resource pooling and knowledge input. It also has limitations such as the small scale and the lack of promotion. Such partnership would be effective only if each partner is committed to work towards the same objectives. Also, the partners should have their own roles and shoulder their responsibilities. For example, the government should provide the required infrastructure while non-governmental organizations focus on environmental education. In the long run however, the private sector should tailor its own system of food waste management along with legislative support from the government. / published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management