This research investigated novel decontamination methods of airborne microorganisms in enclosed public spaces. There are many ways the pathogenic micro-organisms can be transmitted from one body to another, which includes for example, physical contact between the contaminated surface to another, transfer of infected blood from a donor to another medium, or respiratory infections where the large droplets containing micro-organisms caused by talking, sneezing or coughing can infect another whether by direct or close contact, and airborne transmission where the tiny aerosol droplets containing the micro-organisms remain in the air for a long period of time thus spreading to wider areas, making this mode of transmission the most effective and thus dangerous. There are many technique and systems in the market today in the field of air cleaning, and many more under development, these include: ozone, plasma, UV, IR, microwave irradiation, passive solar exposure, pulsed light, electrostatic precipitation, photo-catalytic oxidation etc. However air decontamination using a laser is an unexplored approach. In general two different mechanisms are studied in detail in this research. The possibility of using radiation from the laser and also using plasma and its bi-products were investigated. Many variations and techniques were evaluated for both mechanisms to optimise each decontamination effect. Two types of lasers were used to investigate the concept of using lasers to decontaminate air: a CO2 laser producing a beam at 10.6 μm in the IR region and a KrF excimer laser producing a beam at 248 nm in the UV region. This research was to investigate and make use of the power that is available in the laser in a certain way to decontaminate the air. The effect of laser beam absorption in the presence of microorganisms was modelled in Matlab and this could be used to analyse any wavelength. Two variations of creating a plasma were investigated, one method used a Chang profiled, uniform field electrode and the other used an increased size flat electrode. The plasma produced from these systems emitted radiation around 200 nm to 900 nm. The Chang profiled electrode, which was manufactured in house, was originally designed to be used as a Nitrogen air laser. However, experiments with a purchased Nitrogen laser (detailed in Chapter 3) did not show any significant bacterial killing so the system was modified to be used as a plasma air decontamination device. The electrode was sized 60 mm x 10 mm, and the discharge volume was varied by altering the discharge gap. The effects of various parameters were investigated including: the discharge voltage, type of pre-ionisers to optimise the discharge and air flow shaping through the discharge region. Microbiological experiments conducted using air seeded with microorganisms was used to test the system’s decontamination efficiency. The second plasma system used larger 200 mm x 30 mm aluminium electrodes. Again various parameters were investigated to maximise the discharge stability which included, type of dielectric medium, type of power source, electrical circuit setup, use of laser marked electrodes, air flow shaping and using multiple electrode pairs running off the same power supply. Again, microbiological experiments conducted using air seeded with microorganisms was used to test the system’s decontamination efficiency. Two further systems were built using the results obtained from testing the 200 mm x 30 mm aluminium electrodes, an Industrial Based Air Decontamination Unit and a Ozone Shock Plasma System. Both systems were comprised with multiple pairs of laser marked electrodes with dielectric media and possible addition of flow shaping. The two systems were tested as before with good effect. The developed prototypes can be applied to most applications where air cleanliness is required.

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

The disposal of anaerobically digested sewage sludge onto farmland in Pima county has created the need to evaluate the potential public health impact of pathogens which are indigenous to sewage and may be present in sludge. The occurrence of enteroviruses and Giardia cysts in sewage sludge before and after anaerobic digestion was monitored for a period of 14 months. This study showed that significant concentrations of enteroviruses and Giardia cysts are present in anaerobically digested sewage sludge being applied to farmland in Pima County. The concentration of Giardia cysts ranged from 1.33 x 103 to 8.6 x 104 per liter of raw sludge and 2.0 x 103 to 2.8 x 104 per liter of treated sludge. The concentration of enteroviruses in sludge ranged from 1.74 x 102 to 1.28 x 104 per liter before anaerobic digestion and from <2 to 5.63 x 10 2 per liter after treatment. The percentage of virus removal after anaerobic sludge digestion varied from 73% to >99.95%. Methods to study the fate of enteroviruses in the sludge-soil matrix were also evaluated. An increase in the ratio of eluant to solids seemed to enhance virus recoveries from sludge:soil mixtures.

WTO Agreements have failed to adequately cater for the needs of developing countries. The WTO Agreements, particularly the SPS Agreements has failed to take into account the special needs of developing and least developing countries and clearly their interests have received no representation in the Agreement. Instead of reducing the negative impact of the SPS measures, the Agreement itself has become a barrier to trade. The problems of its implementation inclusive of the expertise, the high costs of conformity, lack of infrastructure and adequate resources have created further restrictions for exporters in international commerce. The failure to adequately deal with the implementation problems of developing countries is evident in the stalemate that culminated at the Doha Ministerial Conference which has extended for over a decade. Perhaps the future of African developments lies in regional agreements, since it is clear that the multilateral trading system has failed. Whereas some scholars are of the view that Article 5.7 of the Agreement should be used as model for the precautionary principle. The principle is highly controversial and does not even have a universal definition; its application might prove to be highly problematic. However the trade-environment debate has already taken center stage in the WTO jurisprudence, suggesting possibly the emergence of an Agreement to that effect. One however can only wonder whether in including the trade-environment debate under the ambit of the WTO when clearly it has failed to deal with issues and concerns’ relating to trade only, might be biting much more than it can chew. / Thesis (LL.M.)-University of KwaZulu-Natal, Durban, 2012.

This thesis explores urban smoke and its nuisances in Georgian England, especially focusing on the period, 1800-1830. During this period, a number of English towns experienced accelerated industrialisation and many of them first experienced air pollution. In 1821, Michael Angelo Taylor, MP, passed a parliamentary bill on smoke abatement, Taylor’s Act. Although it has generally been believed that the Act did not have much of a social impact, this thesis argues that the Act diffused the usage of smoke abatement technology and triggered dozens of legal cases. The geographical focus of this thesis is Leeds and London. The Leeds case study examines the Leeds smoke abatement campaign and the smoke nuisance court case against Benjamin Gott, a leading merchant/ manufacturer in Leeds. It shows that the confusion over the effectiveness of smoke abatement technology represented the main difficulty in the smoke abatement campaign. The court case between the Duke of Northumberland and Clowes represents an example of the London nuisance cases in the 1820s. After the introduction of the steam press, the printing business became a polluting business. Because the plaintiff was the aristocrat, the case was interpreted as a class issue between aristocrat and middle-class printer. However, it was the Duke’s servants who suffered most from the nuisance and the case shows more complex class politics. This thesis also explores smoke nuisance caused by conventional smoke-producing industries in London, waterworks and brickmaking. Some water companies adopted smoke abatement technology but the confusion over the effectiveness of the technology can be observed in London, too. Taylor’s Act did not directly influence brickmaking business but it could cause nuisance to its neighbours, especially nurseries and gardens.

Wastewater effluent produced in the fiberglass manufacturing industry contains a significant amount of total suspended solids. Environmental regulations require pretreatment of effluent before it is discharged to the municipal wastewater treatment plant. Chemical precipitation by coagulation and flocculation is the method of pretreatment used at the Vetrotex CertainTeed Corporation (VCT). A treatability study was conducted to determine conditions at which the VCT Wastewater Pretreatment Plant could operate to consistently achieve a total suspended solids concentration ≤ 200-mg/L. Jar tests varied pH, polymer dosage, and ferric sulfate dosage. Total suspended solids and turbidity were measured to evaluate treatment performance. The data were used to determine an optimum set of conditions under project guidelines. Of twelve polymers screened, BPL 594 was selected as the most effective polymer. For cost efficiency in the wastewater pretreatment operation, recommendations suggested that treatment chemical injection be electronically controlled according to turbidity of the treated effluent.

A collaborative pilot study of the microflora on biological activated charcoal (BAC) filters employed in the tertiary treatment of drinking water revealed the principle bacterial genera to be Pseudomonas, Alcaligenes, Achromobacter, Bacillus, Micrococcus, Corynebacterium, Chromobacterium, Microcyclus and Paracoccus. The microbial population of the filters paralleled seasonal carbon dioxide production. Of particular interest were the effects of the BAC miroorganisms upon precursors of trihalomethanes (THMs). Mixed populations of BAC microorganisms were cultivated for 50 days in a mineral salts-humic acid medium. It was concluded that (1) the BAC microflora enhances the absorptive capacity of the filters; (2) chemico-physical and biological processes operate in concert to lower the concentration of precursors of THMs; and (3) few bacterial pathogens establish themselves on the filters.

"In order to gain an adequate idea of the sanitary condition of the drinking fountains on the North Texas State Teachers College campus, it was found necessary to approach these bacteriological studies from a seasonal point of view."--1.

The optimisation of biogas digesters is crucial for further development of sustainable energy sources. In this research, an integrative approach was taken to understanding how this problem can be addressed including: seeking a better understanding of protein – surface interactions on the molecular level; larger scale experiments to screen the best materials for use in laboratory scale anaerobic digesters to influence microbial growth and biofilm development as well as analysis of farm-scale data using the ADM1 multiparameter model. The laboratory-scale experiments were undertaken to develop surfaces suitable for studying microbial immobilization. This work, currently using tertiary amines, amine oxides and comparator oligoethylene glycol studies the adsorption of two classic model proteins: lysozyme and fibrinogen using quartz crystal microbalance methods and represents important steps for selecting and exploring surface – protein interactions. The data showed that tertiary amine oxides are more resistant to nonspecific protein adsorption than the corresponding tertiary amines. Heat modified polyurethane foam was used to explore biofilm and planktonic phase microbial populations in a fixed film biogas reactor. After four weeks the foam was analysed by ‘next generation’ 454-sequencing to identify the influence of the supporting materials on microbial population residing in anaerobic digesters. The results revealed that Spirochaetes, Methanobacterium and Methanocorpusculum associated themselves with heat modified polyurethane foams. Finally, data from a farm-scale anaerobic digester (volatile fatty acid concentration, temperature and pH) have been gathered and entered into the ADM1 model, developed by the mathematical modelling group from Lund University, to mimic the behaviour of a laboratory scale 1.5 l reactor and identify improved conditions for methanogens stability. The combination of approaches described above will allow the identification of which parameters will enhance the operation of anaerobic digesters and has identified surfaces that promote adhesion of particular Bacteria and Archaea in order to increase biogas production.