There is around 9.5 kJ/L of energy contained in UK wastewater which is wasted through traditional aeration treatment. Microbial fuel cell (MFC) technology provides a new approach to carry the promise of both treating wastewater without aeration and producing renewable energy in the form of electricity and H2. This work has contributed to making this a reality. In this work, MFC designs were developed and constructed to test their energy performances. The power densities ranged from 13.3 mW/m2 to 30 mW/m2. The coulombic efficiency based on the contained substrates is in the range of 1 % to 7 0/0. The Chemical Oxygen Demand (COD) removal conversion per pass of MFCs arrived at 3.0 0/0. The H2 recovery rate was about 14 % with H2 yield of 11.6 mg/g COD. Comparative study suggested that continuous flow, no membrane and single chamber design can be used effectively in MFC for further application. The high temperature CO2 oxidation treatment of carbon anode materials resulted in an improvement of power by a factor of 2 when applied to MFC. Scanning Electron Microscopy (SEM) study and the textural property measurements based on Brunauer Emmett Teller (BET) theory suggested that treatments help bacteria to grow on the material surface resulting in power improvement. Graphite as cathode decreased the MFC power density by around 50 % compared to that of MFC with Pt contained cathode, but the cost is 1/1000 that of the Pt makes it a very attractive alternative. A typical industry case study for implementation of MFC were carried out that considerable energy cost savings and water disposal savings can offset the installation within 1-2 year. It shows that the MFC technology has a promising future for the sustainable development of the world with further research.

Hydrogen as an energy vector offers great potential for mobile energy generation through fuel cell technology, however this depends on safe, mobile and high density storage of hydrogen. The destabilised multi-component complex hydride system LiBH4 : MgH2 was investigated in order to characterise the destabilisation reactions which enable reduction of operating temperatures for this high capacity system (ca. 9.8 wt.%). In-situ neutron diffraction showed that regardless of stoichiometry similar reaction paths were followed forming LiH and MgB¬2¬ when decomposed under H¬2 and Mg-Li alloys (Mg0.816Li0.184 and Mg0.70Li0.30) when under dynamic vacuum. Hydrogen isotherms of the 0.3LiBH4 : MgH¬2¬ showed a dual plateau behaviour with the lower plateau due to the destabilised LiBH4 reaction. Thermodynamic data calculated from the isotherm results showed a significant reduction in the T(1bar) for LiBH4 to 322 C (cf. 459 C for LiBH4(l)). Cycling behaviour of 0.3LiBH4 : MgH2 system decomposed under both reaction environments showed very fast kinetics on deuteriding at 400C and 100 bar D2, reaching 90 % conversion within 20 minutes. In contrast 2LiBH4 : MgH2 samples had kinetics an order of magnitude slower and after 4 hours conversions <50 %. These results demonstrate the strong influence of stoichiometry in the cycling kinetics compared to decomposition conditions. Investigation of catalysts found dispersion of metal hydrides through long ball-milling times, or dispersion through reaction with metal halide additions provided the greatest degree of kinetic advantage, with pre-milled NbH providing the best kinetic improvement without reducing capacity due to Li-halide formation. Finally, additions of LiAlH4 to the system formed an Al dispersion through the sample during decomposition, which acted both as a catalyst and destabilising agent on the MgH2 component, forming Mg-Al-Li alloys. Decomposition under H2 also showed a destabilisation effect for the LiBH4 component.

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Fast pyrolysis of biomass is a significant technology for producing pyrolysis liquids [also known as bio-oil], which contain a number of chemicals. The pyrolysis liquid can be used as a fuel, can be produced solely as a source of chemicals or can have some of the chemicals extracted and the residue used as a fuel. There were two primary objectives of this work. The first was to determine the fast pyrolysis conditions required to maximise the pyrolysis liquid yield from a number of biomass feedstocks. The second objective was to selectively increase the yield of certain chemicals in the pyrolysis liquid by pre-treatment of the feedstock prior to pyrolysis. For a particular biomass feedstock the pyrolysis liquid yield is affected by the reactor process parameters. It has been found that, providing the other process parameters are restricted to the values shown below, reactor temperature is the controlling parameter. The maximum pyrolysis liquid yield and the temperature at which it occurs has been found by a series of pyrolysis experiments over the temperature range 400-600°C. high heating rates > 1000°C/s; pyrolysis vapour residence times <2 seconds; pyrolysis vapour temperatures >400 but <500°C; rapid quenching of the product vapours. Pre-treatment techniques have been devised to modify the chemical composition and/or structure of the biomass in such a way as to influence the chemical composition of the pyrolysis liquid product. The pre-treatments were divided into two groups, those that remove material from the biomass and those which add material to the biomass. Component removal techniques have selectively increased the yield of levoglucosan from 2.45 to 18.58 mf wt.% [dry feedstock basis]. Additive techniques have selectively increased the yield of hydroxyacetaldehyde from 7.26 to 11.63 mf w.% [dry feedstock basis]. Techno-economic assessment has been carried out on an integrated levoglucosan production process [incorporating pre-treatment, pyrolysis and chemical extraction stages] to assess which method of chemical production is the more cost effective. It has been found that it is better to pre-treat the biomass in order to increase the yield of specific chemicals in the pyrolysis liquid and hence improve subsequent chemicals extraction.

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This project has investigated the degradation of freshly harvested Willow chips, thermally treated wood pellets and white wood pellets in both indoor and outdoor storage. Novel research has been carried out, by combining a range of fuels, storage scenarios, stockpile sizes and weather/seasonal patterns. A wide spectrum of tests was regularly performed on the stored fuel samples, to determine the extent of chemical, mechanical and biological degradation. The storage trials have been divided into Phase 1 and Phase 2, with Phase 1 starting in April 2011 and Phase 2 in November 2011. The results showed that the extent of chemical degradation was not significant for the different fuels. The main concern for the Willow storage was the high concentration of different fungi on the chips and two pathogenic fungi were identified. In order to fully appreciate the deposition, inhalation and ingestion potential of fungal spores, the release mechanism of the spores from the wood fuels into the air would be recommended as future work. The indoor white wood pellet pile stored in an open barn suffered severe mechanical degradation and it would be therefore advisable to store white wood pellets in a fully enclosed environment with no exposure to ambient temperature and humidity. For the thermally treated pellets, the extent of degradation in the outdoor piles was far more significant than in the indoor one, with rainfall and humidity having an impact on the extent of degradation. Therefore, while the long term storage of thermally treated wood pellets in an open barn with covered storage would be a viable option; pellets stored in outdoor stockpiles would still be vulnerable to mechanical degradation. So outside storage of thermally treated pellets might be an option for short term strategic stocks, but in the majority of cases, covered storage would still be necessary.

Considerable effort has been devoted to the M-N-H system for solid-state hydrogen storage. However, the desorption mechanism is still unclear and the desorption temperature is too high for practical considerations. Here, the desorption characteristics of LiNH2 and a mixture of (LiNH2+LiH) were firstly comparatively studied by simultaneous then-nogravimetry, differential scanning calorimetry and mass spectrometry for further understanding of H2 desorption in the (LiNH2+LiH) system. Mass spectrometry and thermal analysis of (LiNH2+LiH) mixtures indicate that approximately 5 mass % of H2 is released at 180*C after four hours of milling without any apparent release of NH3, whereas insufficient mixing of the two compounds cannot stop the escaping of NH3 from the mixture. Non-unifon-ri mixing can lead to the escape of NH3 from the mixture. The evidence further supports the notion that NH3 intermediated reaction is a possible reaction path within the thermal desorption of the (LiNH2+ LiH) mixture. BN additive, among selected nitrides shows the best effect on desorption from (LiNH2+ LiH). (LiNH2+MgH2)materials with different molar ratios (4: 3,4: 2 and 4: 1) were also studied for their sorption properties and mechanisms. Results show that more than 6 mass% H2 is desorbed from 1500C for the (4LiNH2 +3MgH2)mixture, with two H2peaks at 200 and 320'C. Meanwhile, there is only -5 mass% for (4LiNH2 +2MgH2) mixture with one H2 peak at 200 T. Reversibility measurements suggest that LiNH2 and MgH2 cannot be recovered after absorption; instead, Li2NH and Mg(NH2)2 (or MgNH) take over to perform the H2 storage functions. The (4LiNH2+3MgH2 ) mixture possess a greater H2 capacity in first desorption, but shows less than 2 mass% reversible capacity in subsequent cycles. However, there is only about I mass% capacity loss during the reversibility measurement for the (4LiNH2 +2MgH2)mixture. Other M-N-H systems, mainly NaH, KH, AlH3 and CaH2, were also investigated, and only CaH2 shows the capability of reacting with LiNH2 to produce H2 among these candidates.