Nitric oxide (NO) is one of the most important air pollutants in atmosphere mainly emitted from combustion exhaust gas. In this research, a biotrickling filter was designed and operated to remove this pollutant from an air stream using bacteria extracted from the sewage sludge of a municipal sewage-treatment plant. The bacteria were cultured and enriched by either petri dish’s cultivation or liquid cultivation. The adsorption capacity of the ceramic material, which was used as the packing material, was determined to be 34 g-NO/L under 37℃. However, the saturated adsorption capacity of the packing material with the recycling solution is 236 mg-NO/L under the operation temperature 37℃.The result suggested that the microporous structure of the ceramic material not the humidity is the main contributor to the ceramic material adsorption capacity. Both the ceramic material adsorption capacity and the removal capacity of the liquid were limited and saturated in 540 min and 2 min operation, respectively. To obtain the best operation conditions for the biotrickling filter, orthogonal experiments (L9 (34)) were designed. The experimental data were analyzed by the signal to noise (S/N) ratio and ANOVA. The optimal conditions of the biotrickling filter occurred at a temperature of 40℃, a pH of 8.00.05 and a chemical oxygen demand (COD) of 165 mg/L in the recycled water with no oxygen in the system. Inlet oxygen concentration was found to be the most significant factor of the biotrickling filter that has a significant negative effect on the NO removal efficiency. The DNA sequencing of four clones of bacteria showed 93-98% similarity to Pseudomonas mendocina strain. This strain has been analysed by full gene sequencing and proved to be a brand-new strain named as Pseudomonas mendocina DLHK. This strain can transfer nitrate to organic nitrogen. This result indicated the assimilation nitrogen process in this system and suggested that the main nitrogen removal capacity in this system was through biological function. Through the isotope experimental analysis, two intermediate products (15NO and 15N2O) have been found during the biological process of the system by using quantitative gas analysis (QGA). These results indicated the denitrification function in this biotrickling filter. A model was developed to explain the biological process in the biotrickling filter. The averaged error of the measured and modeled data is -0.047. The standard deviation of the error is 0.039. The model prediction is in good agreement with the experimental data, particularly at small packing height. Most NO removal capacity was achieved at the first 5 cm packing material. The effects of the axial interstitial velocity and the biofilm coverage to the NO elimination were studied by the model that provided a basic for the design of a biotrickling filter. The biotrickling filter could be used for exhaust gases treatment. The assimilation function in the biological system could be another way to utilize the nitrogen component in the waste gas from harmful to benign nature. The isotope labeling technology is a new method to detect gas components for complex gas samples. / published_or_final_version / Mechanical Engineering / Doctoral / Doctor of Philosophy

Objective This review aims to investigate (i) the concentrations of air pollutants/bacteria in the underground mass-transportation in comparison to the above-ground environment; and (ii) the health implications upon exposure to the underground mass-transportation environment. Methods A systematic review was conducted using keyword searches in Medline, PubMed and ScienceDirect. After screening for relevance, 25 papers are extracted and critically reviewed. Results A number of air pollutants/bacteria/fungi were found having higher concentrations in the underground mass-transportation as compared with those in the above-ground environment. Air quality in the underground mass-transportation is influenced by factors like the service years of subway since operation, train specifications, sampling time, and sampling location. No acute implications were identified, but irritations, human cell damages and anti-inflammatory responses were identified. Conclusion Air quality in underground is worse than in the above-ground environment except for the more recently built subway systems. Research for health implications upon long-term exposure to underground environment is recommended. / published_or_final_version / Public Health / Master / Master of Public Health

The study of air and water flows induced by water level changes is important for a better understanding of water release in response to pumping in unconfined aquifers and give new insights into pumping test data analysis. To improve the unsaturated flow and air-water two-phase flow numerical modeling of unconfined aquifer pumping tests, an improved unsaturated hydraulic conductivity model and a new relative air permeability model were proposed. A synthesis of the literature on subsurface airflow induced by natural forcings was presented to provide a better understanding of the generated airflow and its importance in environmental and engineering applications. A literature review was carried out to study the naturally occurring subsurface airflow. Analytical studies were carried out to derive the improved unsaturated hydraulic conductivity model and the new relative air permeability model. Experimental studies were conducted to investigate the air and water flows induced by drainage and pumping and numerical simulations were carried out using TOUGH2 and TOUGH2-MP to interpret the experimental data. Numerical models for unconfined aquifer pumping test analysis were built with TOUGH2-MP to investigate the effect of heterogeneity on pumping test results. The study of relative permeability models found that the relative permeabilities predicted by the proposed models are in better agreement with experimental data than existing models. Experimental and numerical investigations on air and water flows induced by drainage and pumping found that significant negative air pressure can be generated in a two-layered system with a low-permeability upper layer. The negative air pressure increases very fast after the start of pumping or drainage, reaches a maximum, and then gradually recovers to atmospheric pressure. The generated negative air pressure can significantly reduce the drainage of water from the column and increase the drawdown. Numerical studies of the effects of local heterogeneity on unconfined aquifer pumping test results found that the drawdown in an unconfined aquifer with a low-permeability zone is significantly greater than that of the homogeneous aquifers but the impact of the low-permeability zone diminishes in the long-term production period. This study presents state of knowledge on naturally occurring subsurface airflow and its implications, proposes improved and new relative permeability models for unsaturated flow and multiphase flow modeling, and offers new insights into the effect of air on water release and unconfined aquifer pumping test data analysis. The present study not only has theoretical significance but also has engineering implications. / published_or_final_version / Earth Sciences / Doctoral / Doctor of Philosophy

Respirable Suspended Particulate (RSP) time series data sampled in an air quality monitoring network are found strongly correlated and they are varying in highly similar patterns. This study provides a methodology for spatio-temporal modeling and forecasting of multiple RSP time series, in which the dynamic spatial correlations amongst the series can be effectively utilized. 　　The efficacy of the Spatio-Temporal Dynamic Harmonic Regression (STDHR) model is demonstrated. Based on the decomposition of the observed time series into the trend and periodic components, the model is capable of making forecast of RSP data series that exhibit variation patterns during air pollution episodes and typhoons with dynamic weather conditions. It is also capable to produce spatial predictions of RSP time series up to three unobserved sites. 　　The Noise-variance-ratio (NVR) form of the multivariate recursive algorithm ((M2) algorithm) that derived by the author can greatly facilitate its practical application in both multivariate and univariate time series analysis. The (M2) algorithm allows the spatial correlations to be specified at parametric levels. The state-space (SS) model formulation can flexibly accommodate the existing inter or intra (auto) correlations amongst the parameters of the data series. 　　Applications of the variance intervention (VI) are exploited and illustrated with a real life case study which involves forecasting of RSP data series during an air pollution episode. This illustrates that time series with abrupt changes can be predicted by automatic implementation of the VI approach. 　　The present study also extended the anisotropic Matern model to estimate the dynamic spatial correlation structure of the air quality data by using mean wind speed and prevailing wind direction in defining the spatial anisotropy. The Anisotropic Matern model by Mean Wind Speed and Prevailing Wind Direction (AMMP) model that devised by the author can avoid huge computational burden in estimating variogram at every variation of the underlying spatial structure. 　　Finally, the findings of this dissertation have laid the foundation for further research on multiple time series analysis and estimation of dynamic spatial structure. / published_or_final_version / Geography / Doctoral / Doctor of Philosophy

Abstract Air monitoring was conducted in a nickel base metal refinery to determine compliance with occupational exposure limits. The hypothesis stated that levels of airborne dust may pose a risk to worker health if compared to the relevant exposure limits. Exposure limits for nickel species are set for the inhalable nickel dust fraction. Personal air samples, representative of three selected areas were collected in the workers’ breathing zones, using the Institute of Occupational Medicine (IOM) samplers. Real-time personal samples were collected randomly over a two-month period in three nickel production areas. Filter papers were treated gravimetrically and were analysed for soluble and insoluble nickel through inductive coupled plasma-mass spectrometry (ICP-MS). Measured concentrations were expressed as time weighted average exposure concentrations. Results were compared to South African occupational exposure limits (OELs) and to the threshold limit values (TLVs) set by the American Conference of Governmental Industrial Hygienists (ACGIH) to determine compliance. Statistical compliance was also determined using the National Institute for Occupational Safety and Health procedure as prescribed by South Africa’s Hazardous Chemical Substances Regulations in 1995. In two of the areas it was found that exposure concentrations complied with the OELs. Some exposures exceeded the OEL values and most exposures exceeded the TLV values in the other area concerned. A comprehensive health risk assessment needs to be conducted to determine the cause of non-compliance.

This thesis presents precipitation chemistry data from a dense network of 18 bulk and one wet-only precipitation collectors across the Metropolitan County of Greater Manchester, in the North-West of England, between January 1987 and December 1988. The samples were analysed for the major ions in precipitation. The data were used to investigate the spatial and temporal variability of non marine sulphate, nitrate, ammonium, calcium and hydrogen, their sources and potential atmospheric removal processes. This study has demonstrated the significant spatial variability of non marine sulphate, nitrate, ammonium, calcium and hydrogen ion concentrations in bulk precipitation from a dense urban network. The spatial pattern of hydrogen showed a significant inverse relationship with that of calcium, showing the importance of calcium species as the principal buffering agent of urban precipitation chemistry. A significant relationship between calcium and non marine sulphate was found using advanced statistical techniques. Calcium is proposed to principally originate from urban 'dust' particles which react with either sulphur dioxide or sulphate particles to ·produce enhanced concentrations of non marine sulphate in precipitation. A significant relationship was also found between nitrate and ammonium using the same statistical techniques and trajectory analysis. It is proposed that ammonia from sources within the U.K. and the conurbation itself, undergoes gas phase reactions with nitric acid to form ammonium nitrate, and that the spatial variability of nitrate in precipitation is likely to be the result of the strong spatial variability of ammonium. It may also be possible that calcium carbonate, from local sources, reacts with ammonium sulphate particles, liberating ammonia. The temporal variability of non marine sulphate, nitrate, ammonium and hydrogen ion concentrations in precipitation was consistent with patterns observed by other workers. Local and meso scale emissions do not seem to greatly affect the temporal variabi1ity of these ion concentrations, the major controlling factor being meteorology. The temporal variability of ammonium and nitrate deposition is more susceptible to the effects of local and meso scale emissions. Mean network concentrations of non marine sulphate, nitrate, ammonium and hydrogen did not differ great1y to interpolated values from the secondary national network for the year 1988. However, sophisticated statistical analysis comparing selected data from the G.M. network to those from two nearby national network sites revealed important differences regarding the sources of some ions in precipitation and their relative strengths.

published_or_final_version / Industrial Engineering / Master / Master of Philosophy

published_or_final_version / Industrial and Manufacturing Systems Engineering / Master / Master of Philosophy

published_or_final_version / Mechanical Engineering / Master / Master of Philosophy

The scope for this project will be to explore, define and satisfy the current need for protection devices against air pollution. The outline for the project will be to explore the matter from an entrepreneurial perspective where the lev­el of feasibility will be of great importance. Cost efficiency, branding and market are all important factors that should align with the product design process and outcome.