Landfilling of municipal solid waste is a major waste disposal method, especially in developing countries despite its pressing environmental challenges. Reuse of the landfill composite has been suggested as a sustainable management option that could limit its negative effect. This research evaluated the compositional trend and characteristics of landfill composites with depth in order to assess its suitability as a precursor for activated carbon. A bulk system classification was used during analysis of the composite parameters (‘more degraded’ and ‘less degraded’ components). Both landfills had similar waste constituents, but varied in relation to moisture, TOC, and heavy metals contents. The elemental and chemical constituents of an active and a closed landfill were compared using Fourier transform - infrared (FTIR) spectroscopy, scanning electron microscope/energy-dispersive X-ray (SEM/EDX) spectroscopy, and proximate analysis. The two landfills had similar major elemental constituents representing 96.5 % and 98.4 % of elemental composition for the closed (O > C > Si> Fe > Ca >Al) and active(C > O > Si > Al > Ca > Fe) landfill samples respectively. A single step chemical activation process of precursor was applied involving irradiation with microwave energy and KOH as the activation agent. The average percentage yield of activated carbon (AC) from active landfill precursor was higher than that from closed landfill for all three depths of sampling (upper, 23.8 and 19.3 %; mid, 52.4 and 34.7 %; lower 35.7 and 27.0 %). Methylene blue adsorption capacity and BET surface analysis indicated adsorption capacity and surface area of AC from degraded precursor increased with depth. All AC conformed to a multilayer adsorption model and a pseudo second order kinetic. Carbonyl and hydroxyl groups were the major functional group on the surface of activated carbon. The AC properties indicated that precursors from both landfills are potentially suitable for generation of adsorbent suitable for removal of cationic dyes and pollutants.

In this work a two-stage reaction system was used for the simultaneous production of carbon nanotubes (CNTs) and hydrogen gas from plastic feedstocks. Initial pyrolysis was undertaken in the first stage heated at 600 C, before the evolved gases were passed to a second stage where a catalyst was held. Carbon deposition builds up on the surface of the catalyst, whilst hydrogen and other gases are then collected downstream. A series of analytical techniques were used to characterise the carbon deposition on the catalysts, as well as any oils or gases produced. Initially, a two stage pyrolysis-gasification process was undertaken with plastics from waste electrical and electronic equipment for investigation into hydrogen production. The introduction of a nickel catalyst led to increased hydrogen production, with small amounts of CNTs observed in the carbon deposits on the catalyst surface. In order to increase the yield of CNTs, different plastics including polyethylene, polypropylene and polystyrene were investigated. The rate of steam injection into the two stage pyrolysis-gasification process was also investigated, and proved significant to obtaining high yields of CNTs and hydrogen. All of the plastics produced CNTs, with the largest yield obtained from the pyrolysis gasification of polystyrene at a steam injection rate of 0.25 g h -1 . Additionally, the use of different catalysts was investigated, with iron, nickel, cobalt and copper catalysts all tested. CNTs were produced on the iron, nickel and cobalt catalysts, with the iron catalyst producing the largest yield. The calcination temperature and metal loading on the nickel catalyst was also studied, with catalyst support interactions of intermediate strength and a higher metal loading producing larger CNT yields. Finally, investigations into the temperature of the second stage where the catalyst was held were undertaken, along with using different ratios of catalyst: plastic sample. These too proved important in achieving large yields of both CNTs and hydrogen.

This thesis describes an investigation on the application of anaerobic contact process treating a variety of wastewaters from food industries (raw molasses, purge wastes, ice-cream and diary wastewaters). The raw molasses is one of the wastes produced from the sugar industries, which contains high concentrations of organic matters and high concentrations of sulphate and was firstly investigated in this work. A series of batch experiments were carried out to establish a suitable feedstock for pilot scale digesters. A 1% mass molasses medium with a COD: N: P ratio of 200: 5: 1 in a buffer system has been shown to give a successful digestion of molasses with a methane yield of 0.36 l/g CODrem and a COD removal of 89 % from the batch experiment 3. Two pilot scale digesters (14.13 1) were fed with the molasses medium that was established from the batch experiment 3 as suitable for this work. Several organic loading rates were investigated. After feeding with the molasses medium for about 30 days, both pilot digesters have reached steady-state conditions with respect to a COD removal in excess of 90 % and methane yield in excess of 0.321/g CODrem. The process kinetics of anaerobic contact reactor for treating four different wastewaters was investigated. The Monod equation and the Contois equation were used to develop two basic steady-state models. The kinetic parameters required for the application of the steady-state models were determined by using the results obtained from four individual experiments for treating four different wastewaters. Both models were evaluated with four experimental results obtained in this work and a set of routine analysis data obtained from a full scale anaerobic contact reactor treating the ice-cream wastewater for Birds Eye Walls Ltd., (Gloucester). It is found that the Contois model would be more suitable than the Monod model for express the process kinetics of the anaerobic contact process in full scale due to the reason that the Contois model considers the effect of variable influent substrate concentration into the prediction. In addition, the Contois model was found to be better than the Monod model to express the process kinetic when treating the wastewater containing the organic matters, which has a slow rate of hydrolysis (i. e. lipids/proteins).

Composting is an effective method of removing a large proportion of biodegradable waste from landfill. The CO2 produced by microbial activity demonstrates the rate of decomposition, and was measured in green waste composting in windrows, a forced aerated bay, an aerated test rig and related to the volatile solid content. The peak respiration rates were 35gC02kgVS",day"1 in windrows, and 290gCO2kgVS"1day"1 in the test rig. Knowing the rate of microbial activity, allows the volume of air required to supply sufficient oxygen to a composting matrix to be determined. Recently introduced treatment regulations require 100% of the waste in a composting system to be maintained above 60 or 70 C for minimum periods. Aeration management methods were evaluated that maximise the rate of temperature increase and distribute the heat generated by microbial activity. Managing re-circulated gases between set CO2 limits was demonstrated to an effective method of encouraging rapid temperature increase. Whilst the lowest recirculation rate of 40m3hr l per m3 of compost was required to ensure 100% of the compost matrix in the test rig was greater than 60 C. The research presented in this thesis demonstrates methods that will aid the design and management of any composting system, especially those treating catering waste.

Traditionally, the UK has relied heavily on landfill as a means of dealing with its MSW, However, the UK waste management industry is undergoing a significant period of change as a result of legislative drivers implemented on an European level. The key driver is the Landfill Directive, which has set targets for the reduction of the quantity of biodegradable waste sent to landfill. This Directive has been implemented in Wales by the Landfill Allowance Scheme (LAS), which essentially sets each local authority an annual tonnage of Biodegradable Municipal Waste (BMW) which it can landfill. Failure to comply with the annual target can result in significant financial penalties which are set at £200 per tonne landfilled over the target. This driver coupled with the ever increasing landfill tax, which is set to increase by £8 per annum, is making alternatives to landfill become more economically viable. As well as these statutory drivers, there are also non-statutory drivers. In Wales, the Welsh Assembly Government (WAG) issued the non-statutory requirement for local authorities to achieve 40% recycling and composting by 2009/10, with a minimum of 15% recycling and 15% composting. It has also been announced that post 2010, the targets are likely to increase rapidly, culminating in a 70% recycling and composting target by 2024/25. This thesis uses a case study authority to investigate whether a Materials Recovery Facility (MRF) coupled with changes to its kerbside provision could assist the region to meet its LAS and WAG targets. Key aspects of the thesis include: a compositional analysis of household waste within the case study authority, to ascertain the quantities of material available for diversion via a dry recyclate and organics collection scheme a review of a variety of different MRFs within the UK and overseas to determine best practice operations the development of a MRF conceptual design based on the information obtained from compositional analysis and the process reviews conducted on other MRFs the efficiency testing of the MRF commissioned within the case study authority to determine its performance and areas which could be improved and, the modelling of various scenarios to determine what changes could be made to waste management practices so as to maximise the quantity of material diverted from landfill, and assist the authority to meet its LAS and WAG targets. The compositional analysis study identified that the average household waste generation within the Case Study Authority was 14.9 kg/hhAvk, which was lower than the Welsh average figure of 17 kg/hh/wk. Participating households typically segregated 4.7 kg/hhAvk and 3.0 kg/hh/wk of dry recyclate and organic material respectively. It was also interesting to note that the compositional analysis established that the average BMW content within the Case Study Authority was 72%, which was significantly higher than the 61% used to define MSW for the LAS purposes. An efficiency study carried out on the first phase of the MRF implementation highlighted that when processing a residual waste (black bag) stream 11.2% was recovered in the form of dry recyclate, and 27.7% in the form of a mechanically segregated fine organic stream (less than 50mm fraction). When processing a dry recyclate stream, the efficiency study identified that 95% of the material was recovered for recycling however, two-thirds of this was in the form of a low grade paper product, which was sensitive to market changes. The thesis highlights that a MRF has a significant role to play in an integrated solution for municipal waste management however, it is clear that ultimately some form of thermal process will be required for the residual waste stream in order for local authorities to comply with the LAS targets.

The combination of increasing quantities of Municipal Solid Waste (MSW) and increased legislation for the disposal of this type of waste have created a need to develop different disposal or treatment routes for waste. Approximately 60% of MSW by mass is biodegradable and many disposal routes for this waste allow energy recovery. However the waste hierarchy presented in the National Waste Strategy for Wales emphasises the importance of materials recovery over energy recovery. It has been shown that the only way to achieve these targets is through the recovery of catering waste, which requires an in-vessel composting facility. In order to gain an insight into the aeration requirements for in-vessel composting, calculations were performed to ascertain the required airflow for the supply of oxygen, the removal of excess moisture and the removal of excess heat. It was found that approximately 450kJ are released for each mole of oxygen utilised whilst 500kJ are released per mole of carbon dioxide evolved. It was found that the air requirement for removal of heat from the process was approximately 100 times greater than the air required to supply oxygen to the system. In order to determine the power of aeration equipment required for composting facilities a static pressure test rig was constructed. From the results gained a model relating the static pressure to the bulk density of compost was developed. Initially a windrow composting system processing green waste at the Carmarthenshire Environmental Resources Trust (CERT) composting facility was studied. A canopy system was developed to monitor the respiration rate of this system and allow comparison between different feedstocks and control strategies. For a green waste only windrow the highest recorded respiration rate was 38gC02kgVS"1day"1. The respiration rate was observed to reduce with temperature above 55 °C. In addition to the green waste windrows a temperature managed windrow and a windrow constructed from a mixture of green waste and chicken litter were also tested. The final series of trials involved the testing of the ability of a containerised composting system to meet the Animal By-Products Regulations. The vessel was fed various mixtures of green waste and factory waste. Airflow and insulation within the vessel were analysed and a composting rate of over 45gC02kgVS'1day1 was achieved. If this had been sustained then the vessel may have met the Animal By-Products Regulations.

Kerbside recycling schemes in the UK are voluntary. In 2003/4, 61% of households in Wales had some form of kerbside recycling scheme collecting at least one material. Householders are encouraged in a variety of ways to segregate targeted recyclables from their general waste and to put this at the kerbside in any number of separate receptacles. There are many ways of increasing the diversion of household waste into kerbside recycling systems. A plethora of incentives, penalties and communications can be offered and many awareness raising schemes can be employed. This thesis uses a case study authority to trial, then subsequently examine the effectiveness of specific methods to increase the diversion of household waste into kerbside recycling systems. A public waste awareness campaign and a schools waste education programme are implemented within the authority a range of incentives were used, some using voluntary approaches and others financial carrots. Key aspects of the work include a legislative overview of household waste in Wales, a quantitative examination of the scale of the household waste problem and a study of attitudes towards waste, actual recycling behaviour and the effectiveness of a waste awareness campaign and a schools waste education programme. It is thought local authorities which implement kerbside recycling and composting schemes, and still have significant tonnage to divert to meet their 2010 diversion targets, will not meet them by implementing voluntary/carrots and financial/carrots incentives alone. Ultimately, alternative waste treatment technologies that do not require households to participate in segregation or a significant change in kerbside recycling behaviour (thought only possible through financial/stick incentives or alternate weekly collections) will be needed for local authorities to meet the 2010 Wales Waste Strategy targets and reach the required BMW diversion set in the Landfill Allowance Scheme. Waste awareness campaigns and schools education campaigns have a role to play, but, should not be solely relied on to meet short term diversion targets.

In recent years the concept of ecosystem services has been becoming increasingly important within environmental policy and decision making. A range of ecosystem services can be provided through the restoration of containment landfills but research to date has tended to focus on constraints rather than what can be provided by them. This study investigates the ecosystem service priorities of stakeholders for grassland and woodland as conventional landfill restoration land uses, and willow SRC as a new restoration land use. The overall priorities of stakeholders, and priorities with regard to trade-offs between ecosystem services are considered. This study also investigates the land use preferences of stakeholders for the delivery of ecosystem service priorities. It identifies conflicts and synergies between stakeholders and how these can be used to enhance sustainable land use planning and management in the context of the restoration of containment landfill sites. Data was collected through a combination of questionnaires and interviews. The study identifies major conflicts between stakeholders over the provision of recreation on sites, and over access being provided to landfill gas infrastructure. The study also identifies that local authority planning requirements, health and safety and the need for access to landfill gas infrastructure, are all potential barriers to the delivery of ecosystem service priorities. In order to maximize the ecosystem services prioritized by stakeholders, several suggestions are made. It is argued that there is: a need for changes in local authority planning requirements; a need for landfill gas managers to be included in decision making, and as statutory consultees in the planning of the restoration of sites, and a need for research into improving the design of landfill gas infrastructure, to enhance its suitability for use on sites that are to be opened to the public. The study also shows how an ecosystem service-based approach can be useful for identifying interests and conflicts and synergies between stakeholders in the context of the restoration of containment landfill sites.

Plastic consumption has increased 8% annually since the 1950 reaching an estimated 300 million tonnes in 2014, where more than 50% was discarded after single-use. Many recycling methods have been proposed to manage this growing waste, but most have practical, environmental and economic limitations. Catalytic conversion, a chemical recycling method using a suitable catalyst, has been suggested as a viable option since it can return plastic to a chemical feedstock, which is the aim of this work. Four potential catalysts, namely sulphated zirconia SZ, calcium carbide CC, molybdenum carbide MC and zirconium oxide ZO were tested for HDPE conversion, which was selected from five different polymer samples due to its high thermal resistance. It was found that only calcined SZ and calcined CC showed some impact HDPE conversion. However, SZ was marked with high coke yield while calcined CC had low conversion with virtually no coke. Therefore a hybrid catalyst was considered, where the SZ and the CC were mixed together on equal weight bases forming the hybrid catalyst SZ1CC1. Fixed bed pyrolysis showed an excellent HDPE conversion of virtually 100wt% using the hybrid catalyst at 410oC with 66.0wt% liquid yield against a 98.0wt% conversion with only 39.0% liquid yield for the pure SZ and no conversion in the case of HDPE only. The hydrocarbon composition of the liquid fraction obtained changed significantly from 58% aromatic and 16% paraffinic for the SZ to 74% olefinic and 23% naphthenic for the SZ1CC1. The improvement in liquid yield and selectivity to non-aromatic liquid was strongly linked to a modification in the acidic strength of the hybrid catalyst SZ1CC1. The moderation in acidity and textural properties, such as surface area and porosity were found to suppress excessive cracking and limiting secondary cracking reactions, that promotes high gas yield and aromatisation in the SZ. Overall, it is concluded that the SZ on its own, which had high acidic strength and large surface area, promoted secondary reactions during HDPE cracking that yielded aromatics. However, the hybrid catalyst SZ1CC1, which had moderate acid strength and low surface area halted any secondary reaction and terminated the cracking reaction at stages that produced only olefinic and naphthenic hydrocarbons.

Among the greatest challenges of the twenty-first century is the rapid growth of cities. The growth of most municipalities has remained unplanned and uncontrolled. Unmanageable development in developing countries has given rise to environmental disorders in the built-up settlements. Municipal solid waste management in particular, is now a fear-provoking assignment for the municipal establishments who are lacking in capacity to confront the municipal solid waste issue. The main objective of carrying out this research is to see how urban planning can help improve municipal solid waste issues in Greater Jos municipal area. It defines the municipal solid waste problem and identifies a number of specific planning drivers as the factors responsible for lack of improvement in the municipal solid waste management situation. A mixed method approach was used for the empirical analysis which combined both interviews and questionnaire data from senior government officials, industry stakeholders and residential neighbourhoods, collected with observational and documentary data, in order to investigate the solid waste issue. Major problems identified in this research are: (i) municipalities are undergoing deterioration of solid waste conditions but the local, state and federal governments are lacking adequate planning to deal with the circumstances (ii) apart from quite a lot of causes of the municipal solid wastes crisis can be known, the political commitment to urban planning is lacking which serves as the basis of the deteriorating situation in Nigerian municipalities and (iii) relationship exists between poor planning and municipal solid waste management delivery of collection services and disposal amenities. Individual municipal solid waste management strategy alone was found to produce unplanned and uncoordinated management of waste issues. Collaboration to produce a joint municipal solid waste management plan has been recommended as a good practice.