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Bioremediation is a promising and cost-effective technology widely used to clean up waste containing organic or inorganic contaminants. Cr(VI), the highest oxidation state of the metal chromium, is widely used in various industries, and is extremely toxic to animals and humans. Utilisation of chromium (Cr) reducing microbes and their products can enhance the efficiency of the process of detoxification of Cr(VI) to Cr(III).This study was conducted to investigate the microbial reduction of chromium [Cr(VI)] in general and the potential for biological treatment of Cr(Vl)-containing wastes in particular. Cr(VI) was transformed to non-toxic Cr(III) by Escherichia coli ATCC 33456. It was observed for the first time that the type I methanotrophic bacterium Methylococcus capsulatus (Bath) is able to reduce chromium (VI) to chromium (III), using methane as the carbon and energy source. The reaction occurred over a wide range of chromium (VI) concentrations (10-1,000 mg/1). The reaction was studied by a variety of techniques, including the diphenyl carbazide assay for chromium (VI), ion chromatography coupled to inductively coupled plasma atomic absorption spectroscopy (ICP-MS), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDSX), X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine structure (EXAFS). The results indicate that chromium(VI) reduction to chromium(III) is wholly or partly associated with the cells via coordination to phosphate moieties. BLAST searches using known chromate (Vl)-reducing enzymes from other bacteria indicated the presence of five potential chromate reductases in the genome sequence of M. capsulatus (Bath). Detailed bioinformatic analysis, including molecular modelling, indicates a possible mode of binding of chromium to two of these. The model type II methanotroph Methylosinus trichosporium OB3b did not reduce chromate (VI) in pure culture, and the future availability of the genome sequence of this organism may give additional clues to the origin of chromate(VI) reduction in M. capsulatus, via comparative genomics. Interestingly, however, mixed cultures of M. trichosporium and E. coli were able to reduce chromate(VI) using methane as the only source of reductant, presumably because the E. coli can scavenge nutrients from the M. trichosporium.

Metal leaching behaviour was investigated in synthetically prepared soils which were contaminated with lead in the laboratory and to which ordinary Portland cement (OPC), lime, magnesia, fly ash (PFA), or ground granulated blast furnace slag (GGBFS) were added to stabilise the contaminant. The optimum amounts were determined by fly ash added gradually to contaminated soil until full reduction of leachable lead was reached. Five grams of the soil thoroughly mixed with 0.1g stabilising material was transferred into a 100ml polypropylene container to which 50ml of de-ionised (DI) water or 50 ml of 0.1M HNO[3] or 0.01M HNO[3] was added. The mixture was shaken on a flat bed shaker for 2 hours, and then filtered using a Whatman No 542 filter paper. The lead concentration in the filtrate was determined by inductively coupled plasma-atomic emission spectrometry (ICP-AES). All theses stabilizers resulted in about 99% of the added lead being retained on the filter. However, in similar experiments with 0.1 M HNO[3] effective lead retention was found only when OPC or GBFS were used where amounts retained were 90 and 95% respectively. The effect of changes in pH on lead retention was investigated using Raman Spectroscopy, X-ray Diffraction (XRD), Fourier Transformation Infrared Spectroscopy (FTIR), Raman Spectroscopy and Scanning Electron Microscopy (SEM) and X-ray photo spectroscopy (XPS) and ion chromatography. In a second series of experiments Lead contaminated solutions containing 10, 50, 100, and 500 mg/1, respectively of Pb were treated by the addition of known quantities of OPC, lime, magnesia, GGBFS or fly ash. The resulting lead-containing precipitate was collected and characterised using XRD, FTIR, Atomic emission Spectroscopy ICP-AES, SEM-EDX , Raman and XPS. Analysis of the supernatant by Inductively Coupled Plasma Spectrometry showed that about 99% of lead in solution was removed after the addition of 0.1g of OPC, lime or magnesia, PFA, or GGBFs to the 50ml of lead solution. Characterisation of the cement treated samples showed the formation of PbCO[3], PbSO[4] and PbSiO[3]. The addition of lime resulted in the formation of Pb2OCO[3], PbSiO[3], PbCO[3] and Ca(PbO[3])[2]. In the presence of magnesia, the following compounds were formed: Mg[2]Pb, PbMgV[2]O[7] and PbO[2]. Results from both IR and SEM-EDX confirmed the presence of lead in the precipitate. When deionised water or 0.1 M HNO[3] was used in the presence of GGBFS, the concentration of lead in the leachate was less than 1% of the added lead in the soil. Results from X-ray diffraction measurements on soil samples retained on the filter paper showed lead calcium silicate and a mixed compound of lead sulphate carbonate hydroxide were formed in the presence of GGBFS. These investigations show that the addition of cement, lime or magnesia, GGBFS and PFA can result in the removal of lead from the solution to form stable compounds, thus providing a potential means of clean-up of solutions contaminated with lead. In addition to the work on contamination with lead, contamination with seven other elements was also investigated: Zn, Pb, Cd, Cr, Cu, Ni, Al. The levels of the concentration of the solution were varied: 10, 50, 100 and 500 mg/1. The solidification procedures were applied with 20,000 mg/l of Pb solution on cube shape 50x50 x50mm samples that were cured for 7 days. Then tank leaching test was conducted on solidified samples together with an acid digestion test. This work was extended to the examination of the leaching behaviour of the compounds formed by subjecting lead contaminated OPC cubes (50x50x50mm), cured for 7 days, to leaching in a tank of DI water. Results showed that less than 1% of the lead had leached out within 15 days. In addition, similarly treated cubes with varying amounts of OPC replaced with fly ash or GGBFS were subjected to the leaching tank and compressive strength tests. The results of the tests showed better retention of Pb where OPC was replaced by PFA or GGBFS.

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Pollution from synthetic dyes, released by textile and paper pulping plants, draws major concern. Textile effluents have negative impact both on the environment and human health because they are toxic and some are carcinogenic. Apart from the textile industry, dyes are also widely used in manufacturing industries for leather products, cosmetics, pharmaceuticals, foods and beverages. It is known that white rot fungi can decolourise and detoxify various industrial effluents through the production of extracellular lignin modifying enzymes, a major class of which are laccases (EC 1.10.3.2). Considering the above, three strains of white rot fungi, Coriolopsis polyzona (MUCL 38443), Pleurotus ostreatus (ATCC no. MYA-2306) and Pycnoporus sanguineus (MUCL 41582) were studied for their ability to produce laccases in liquid media. The effects of mannan oligosaccharides (MO) as elicitor and ferulic acid as inducer were studied using central composite experimental design in liquid cultures of the three strains. The results showed that MO, either added alone or combined with ferulic acid, enhanced laccase activity in the three different cultures and the enhancement was species specific. The highest increase was in liquid cultures of P. sanguineus (88-fold) followed by P. ostreatus (3-fold) and C. polyzona (2-fold), among which C. polyzona resulted in the highest laccase activity. The combined addition of 150 mg/l of MO and 1 mM ferulic acid resulted in the optimal laccase activity by C. polyzona, whereas additions of 75 mg/l MO to the cultures of P. sanguineus and P. ostreatus led to the optimal activity. Extracellular laccase activity was considerably increased when C. polyzona was grown in glucose-bactopetone based culture medium induced by ferulic acid. The effect of inoculum conditions on laccase production was studied at reactor scales. Laccase activity achieved with conidia inoculation was higher compared with mycelium inoculation at the early stage of fermentation. However, the laccase levels were similar after 23 days of fermentation (110 U/ml and 100 U/ml for the conidia and mycelia pre-culture respectively). The conidia inoculation is preferred in scale-up when time-cost is considered. The maximal laccase activity with conidia inoculation in a 2 litre stirred tank reactor was 27% higher compared to that in shaken flasks. This showed that C. polyzona cultures have the potential to be scaled-up for increased laccase activity by applying conidia inoculum. The fermentation of C. polyzona was scaled-up to 20 litre and 150 litre stirred tank reactors applying fed-bath strategy. This resulted in 100 % enhancement of laccase activity. Addition of oak wood powder in the culture medium increased total laccase activity indicating the potential of lignocellulosic wastes as alternative substrates for enhanced laccase production with reducing cost. In order to investigate the application of laccases in dye decolourisation, two major laccase isozymes (Lac I & II) from C. polyzona were purified to apparent eletrophoretic homogenetity using hydrophobic interaction chromatography and ionexchange chromatography. Both enzymes were found to be monomeric proteins with the same molecular mass of 63 kDa, and isoelectronic point of 4.3. Their catalytic activities were studied under various substrates, pHs and temperatures. The highest enzyme affinity and efficiency were obtained with 2,2′-azino-bis- (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS). Compared with other fungal laccases, the laccases from C. polyzona have very low Km values with ABTS as a susbtrate. The optimum pHs were 2.8, 3.0 and 5.0 on ABTS, 2, 6-dimethoxyphenol (DMP) and syringaldazine, respectively. Both isozymes had acidic optimal pH values. However, they were more stable in netural pH rather than at acidic pH. Moreover, mass spectrometry (MS) analysis of tryptic digestion products of the two isozymes was performed, which showed further similarity of these two isozymes. As common physical or chemical methods for dye removal are expensive, have low efficiency and sometimes generate other pollutants, the decolourisation of industrial effluents containing single and mixed dyes was investigated using purified laccase (Lac I) from C. polyzona as well as whole cell culture. The method appeared to be an attractive alternative for dye removal. Anthraquinone dyes were found to be more easily decolourised by Lac I compared to azo dyes. The addition of redox mediator ABTS and violuric acid (VA) improved considerably the catalytic efficiencies of azo dyes. Decolourisation, 40-50 %, was achieved for the reactive and the direct dye baths. Response surface technology (RSM) was applied to optimise the decolourisation of the diazo dye reactive black 5 (RB 5) by Lac I. Box-Behnken experimental design with three variables including laccase activity (100, 200, 300 U/l), pH (5, 7, 9) and VA concentration (0, 1.25, 2.5 mM) was studied to identify a significant correlation between the effect of these variables on decolourisation of RB5. The experimental values were in good agreement with the predicted values with the correlation coefficient of 97.4%.

The State of Kuwait is one of the major oil-producing countries with its economy solely and directly dependent on export of crude oil and its refined products. Kuwait Oil Company (KOC) is responsible for the exploration, development and production of marketable quality hydrocarbon, Although KOC has a very strict flaring policy and practices, emission of some gaseous pollutants to the atmosphere; particularly from the flaring of normally undesirable effluent streams and excess gases. This study provides a comprehensive account and estimates of all emissions of primary pollutants associated with flaring activities from Kuwait Oilfields. This inventory provides the monthly emissions for a decade starting for year 1997 of air pollutants: NOx, SO2, CO, CO2, methane and non-methane hydrocarbons. The emissions are generated from various point sources and aggregated to obtain total pollutants load of ambient air in and around oilfields. The emissions of pollutants from the flaring associated with all types of operations in the oilfields, gathering centres (GC), booster stations (BS), tank areas and other oil production related emission activities.

A study of water supply was carried out at Elobeid to evaluate the effect of any deficiencies and the need for improved services in relation to economic, social and environmental conditions. World-wide investigations correlating water supply with health and economic development were reviewed. Data were obtained from 235 households, representative of the total population, regarding water use, health, living conditions etc. Information about water resources was obtained from governmental departments. The data were analysed with the aid of a computer. Typical to other towns in Sudan, Elobeid is characterized by distinct social classes. Water supply appears to be seriously deficient in quantity, quality and reliability. Households using insufficient volumes of water have above 25 days illness per person per year due to water-related diseases, and especially water-washed diseases; child mortality rises to over 60%. A model was constructed to relate the incidence of disease and water consumption.

The research for this thesis investigated user-product relationships with Local Authority public convenience sanitaryware products. The focus of the research was concerned with the in-use relationships the UK public, and those visiting, have with these multiuser public use products. The research aimed to identify which design attributes were and were not enjoyed, and to represent the views of the UK public. The literature review highlighted a lack of knowledge in the area of the specific multiuser public use products; toilets, urinals and sanitary waste units. It also highlighted a lack of user-centred research into the design of sanitaryware for able-bodied access use. Due to the sensitivity of the subject and lack of information available, a mixed-methods approach to information elicitation was adopted. Recruiting participation for the studies was also approached with care to demonstrate the validity of the research. In total over 450 self-selected volunteers participated in this research.

For centuries, the dominant form of waste disposal has been landfill, however, this is now deemed to be non-viable from a social, legislative, environmental and economic perspective. Therefore, more sustainable methods of waste disposal are needed globally to reduce the amount of waste going to landfill (e. g. composting). This thesis considered two different forms of in-vessel composting and their effectiveness in treating the biodegradable fraction of Municipal Solid Waste (MSW) that had been mechanically separated prior to composting in two areas of Wales. Further to this, the potential for using MSWbased composts as growth media was investigated alongside the physical composition of MSW-based composts. This thesis found that primary-screened MSW contained a high amount (>50%) of biodegradable matter with varying amounts of glass (ca. 23%), plastic (ca. 10%) and other components present. Both in-vessel composting methods were successful at treating MSW and produced composting profiles similar to those for green waste (e. g. increased pH, reduced EC and increased N03" content). Alongside this, both methods also reached temperatures high enough to cause destruction of human enteric pathogens making them compliant with the 2005 Animal By-Products Regulations. Inert matter (i.e. glass and plastic) remained unchanged during composting, but beneficially enhanced composting by improving aeration. In contrast, small bench-scale composting units failed to realistically mimic the performance of the larger scale MSW composting systems; the results obtained with them suggested that commercial composting additives did not enhance the rate of composting. The use of the MSW-based growth media showed that as the materials matured, yields of two common pasture land species increased significantly, and in some cases exceeded those of commercially available growth media used widely in horticulture. Combining agricultural soils with these MSW-based materials gave increased plant yields in comparison to soil alone, however, the benefits were dependent on the amount and type of MSW compost added. Further research is needed into the removal of physical and chemical contaminants from the parent materials for composting of MSW based materials along with clearer legislative definitions as to the possible end uses for such materials. The presence of clear markets has the potential to drive improvements in the technology used for MSW composting. In conclusion, composting provides a viable method for the treatment of MSW-derived biodegradable waste and has the potential to form an important component of sustainable waste management in the UK.

The intention of this study was to investigate the two most significant sources of dissolved organic carbon (DOC) to drinking water supplies; peatlands and algae. For two drinking water reservoirs in north Wales, Llyn Cefni and Llyn Alaw, markedly different seasonal trends were recorded, and these were linked to contrasting aspects of the lake's catchment and the meteorological conditions experienced during the two surveys. For Llyn Cefni, the DOC signatures for the inflowing streams and lakes correlated significantly, Afon Erddreiniog (R2=0.585, p<0.01) and Afon Cefni (R2=0.784, p<0.001), indicating a strong flux of terrestrial DOC into the lake from a nearby peatland. Much less of a seasonal trend in DOC was recorded at Llyn Alaw, with concentrations averaging 10.7 mg L 1, reflecting the absence of a peaty catchment. DOC derived from autochthonous production was also shown to be influential. Both lakes experienced nitrate depletion during the summer of the surveys, falling from 12.7 mg L-1 in Llyn Cefni and 6.5 mg L"' in L lyn Alaw to undetectable levels, suggesting extreme eutrophy, although the lack of detectable phosphate at Llyn Alaw may be why the growth of algal blooms was much less prevalent than at Llyn Cefni. A new type of floating constructed wetlands (FCW) was shown to Offer a potential solution 'to the production of algal blooms in the reservoirs, whereby over a four-week period, the FCWs were able to reduce algal growth by 80%, through sequestration of the key nutrients nitrate and phosphate and possibly due to the direct inhibitory properties of phenolic compounds on the algae. Furthermore, it was discovered that 8 Phragmites aus/ralis plants is the ideal number to maximise nutrient uptake and minimise algal growth in 70 litres of water. Studies in Finland and Malaysia were undertaken to highlight the importance of peatland management practices, as' vast areas of the world's boreal and tropical peatlands have been drained for agricultural purposes. The study in Finland showed that although there was noconsistent response in DOC export potential with drainage across the sites of contrasting nutrient status, a significant correlation was observed between DOC and the water content of the soil, R2 = 0.59 (p< 0.001), indicating that as the water-table height falls the DOC export potential of the soil increases. It was also considered that the trend in DOC is driven by changes in soil pH and the resulting suppression of the key carbon regulating enzyme phenol oxidase; where acidity has increased following drainage phenol oxidase activity has declined and the concentration of DOC released has increased, conforming the view that phenol oxidase acts as an `enzymic latch' in peatlands. The study in Malaysia recorded a 40% greater export potential of DOC from the oil palm soil and more than twice the DOC concentration in drainage waters compared to the undisturbed peat soil. The activity of the key hydrolytic enzyme ß-glucosidase was 25% higher in the oil palm soil than the undisturbed peat. This may be due to an improved soil organic matter quality at the oil palm site and suggests that increased activity of this enzyme may have been crucial for mobilising DOC from the soil matrix. The repercussions of these studies are discussed with emphasis on the potential impacts of a changing climate.