The structure and function of microbial communities are critical to the maintenance and sustainability of terrestrial ecosystem processes. Consequently, there is substantial interest in assessing how microbial communities respond to various land management practices, and if alterations to the characteristics of microbial communities has the potential to disrupt ecosystem processes. This thesis was conducted to identify the long term effects of fertilisation and different levels of post-harvest organic matter removal on the characteristics of the FH litter and soil microbial communities in six, second rotation Pinus radiata plantation forests located around New Zealand. The six sites, established between 1986 and 1994, were sampled in 2002 and 2003. Various physical and chemical properties of the sites were measured, and litterfall production was determined. The microbial biomass in the FH litter layer and soil was determined by chloroform fumigation-extraction, and Biolog plates were used to assess the relative differences in microbial community diversity, based on patterns of substrate utilisation. Fertilisation substantially altered the physical and chemical properties of the forest floor, including FH litter moisture content, mass, carbon content, nitrogen content and carbon: nitrogen ratio and soil pH, nitrogen content and carbon: nitrogen ratio. The same range of FH litter and soil properties were also significantly changed by different levels of organic matter removal. The biomass and diversity of the FH litter and soil microbial communities were significantly altered by fertilisation and organic matter removal, and the differences in the microbial community characteristics were significantly correlated to the effects of the fertilisation and organic matter removal treatments on the physical and chemical environment in the majority of cases. The physical and chemical properties of the sites were significantly correlated to estimates of wood production, and it was also found that the characteristics of the microbial community were strongly related to productivity at several sites. The results demonstrated that fertilisation and organic matter removal regimes have had long term effects on the microbial communities at the sites. The persistence of the effects of the organic matter removal treatments were particularly noteworthy, as these treatments were applied at site establishment, and despite no subsequent reinforcement over the life of the trials, were still substantially influencing the physical, chemical and microbiological properties of the FH litter and soil up to 17 years later. The results of this thesis also emphasised the value of long-term experiments in assessing the effects of disturbance on the physical, chemical and microbiological characteristics of forest ecosystems. Further research into the specific nature of the relationship between site productivity and microbial community characteristics was suggested as an important focus for future studies.

The search for alternative water disinfectants to those commonly used, such as chlorine, probably began when the disadvantages of those disinfectants became known. Soluble disinfectants have short half-lives and need to be replenished periodically which requires monitoring the determination of appropriate concentrations for waters being treated. This disadvantage may be balanced by the ability to alter dose concentrations of soluble disinfectants to meet changes in demands. Maintenance of a residual disinfectant concentration which can act throughout a water distribution system is another advantage of soluble disinfectants. Disadvantages due to reaction of organic materials include the loss of disinfecting capability, health hazards related to the disinfectant and the potential loss of aesthetic water qualities such as taste, smell and color. The purpose of this study was to investigate different surface contact disinfectants which, while having an inflexible dose concentration capability and releasing no residual disinfectant concentration, do not require monitoring and do not significantly leach into the waters they contact. Powdered aluminum when mixed with a loamy sand reduces virus concentration 3-4 orders of magnitude better than controls while not significantly altering the pH or aluminum concentration of waters that pass through the soil columns. Labeled poliovirus 1 was found to adsorb onto the aluminum surface in batch experiments and undergo degradation or dissociation of the capsid proteins with release of viral fragments and clumps within 76 hours. Freon dispersion of the viral clumps showed the clumps to be non-infective. Polyacrylamide gel electrophoresis of poliovirus 1 incubated with aluminum for 76 hours suggested degradation or dissociation of viral capsid proteins 1, 2 and 3. Magnesium peroxide and magnesium oxide, while effectively inactivating viruses, significantly increase the pH of water which they contact. Polyhalex resin and I5 resin reduce virus concentration, but release functional groups into the surrrounding water. Contact disinfectants such as aluminum, may find point-of-use application for drinking water, use in septic tank leachfields or sewage treatment infiltration basins to reduce the threat of spreading potential disease-causing organisms.

Nucleic acid hybridization (gene probe) and polymerase chain reaction (PCR) techniques have been used to detect viral nucleic acid in water. However, gene probe and PCR may not distinguish between infectious and noninfectious viruses. This study evaluated the ability of gene probe to detect viable poliovirus 1 (polio 1), from sterile and nonsterile groundwater, and the ability of PCR to detect infectious human immunodeficiency virus (HIV-1) from tap and wastewater. The plaque forming (BGM cells), and the tissue culture infectious dose fifty (TCID₅₀) (PLC/PRF/5 cells) procedures were used to detect infectious polio 1 and HIV-1, respectively. Detection of polio 1 by gene probe and cell culture was similar in nonsterile water and in filter sterilized water, but not in autoclaved water. These results suggest that in some natural waters, detection of polio 1 by gene probe may correlate to detection by cell culture procedures. Although detection of infectious HIV-1 by cell culture decreased gradually, until no virus could be found, detection by PCR remained positive throughout the study. Therefore, it was concluded that the use of PCR to assess the risk associated to the presence of HIV-1 in polluted waters, may not be adequate. The enteric adenovirus types 40 (Ead 40) and 41 (Ead 41) are considered the second most important cause of viral gastroenteritis in children, but their role as waterborne pathogens is uncertain. This study compared the survival of Ead 40 and Ead 41 with polio 1, and hepatitis A virus (HAV) in different types of water. The Enteric adenoviruses survived longer in tap and sea water than either polio 1 or HAV, but only slightly better in wastewater. These results suggest that the enteric adenoviruses may survive for prolonged periods in water, representing a potential route of transmission. This study evaluated also the concentration of Ead 40 by the filter adsorption-elution method. With negatively-charged filters, recovery efficiencies of 22, 36, and 38% were obtained from secondary sewage, tap and sea water, respectively. Using electropositive filters, Ead 40 was recovered from tap water with an efficiency of 26.5%. These results show that Ead 40 can be concentrated, from water, with an efficiency comparable to that of other enteric viruses.

The isolation of viruses from treated drinking water has raised concerns that water treatment methods may not always adequately insure the removal of viruses from water designated for human consumption. The isolation of enteroviruses and rotavIruses from treated drinking water in a distribution system and at a water treatment plant has been previously reported. Isolation of viruses from drinking water that met recommended levels of coliform bacteria, chlorine and turbidity. The question is raised as to whether or not current drinking water standards ensure safe drinking water. The isolation of enteroviruses and rotaviruses from treated drinking water In a distribution system and at a water treatment plant. This study reports the results of a more extensive investigation on the removal of naturally occurring viruses by water treatment processes including prechlorination/clarification, filtration, and chlorination at a fullscale water treatment plant. The removal of enteroviruses and rotaviruses was studied at a full scale 205 mgd water treatment plant involving chemical clarification, sand filtration and chlorination. Enteric viruses, as well as coliphages, indicator bacteria, physical and chemical variables were measured in water samples taken at each stage of the drinking water treatment facility. Linear intercorrel ations were analyzed for all the variables. The numbers of standard plate count bacteria and coliphage were positively correlated to the presence of enteroviruses in the raw water while coliphage counts were positively correlated to the presence of rotaviruses in the finished water. Samples were taken during the dry and rainy seasons. During the dry season, it was found that reduction of enteroviruses and rotaviruses averaged 81% and 93%, respectively, for the complete treatment process and were the least efficiently removed as compared to the other microorganisms. The greatest reduction of enterovIruses occurred during pre-chlorination/flocculation and filtration, while a significant reduction of rotav I ru ses occurred during prechlorination/ flocculation and final chlorination. Enteroviruses or rotaviruses occurred in 24% of the finished water samples containing chlorine levels of >0.2 mg/L, and meeting coliform bacteria (1/100 ml) and turbidity (1 NTU) standards. During the rainy season removals were found to be far less efficient for all the variables and rotaviruses were isolated from all finished water samples. The results of this study indicate that finished water having measurable levels of free residual chlorine and meeting standards for col iform bacteria, and turbidity cannot be assumed to be virus free.

The treatment of synthetic landfill leachate and raw landfill leachate were investigated using two sets of 3 L aerobic sequencing batch reactors (SBR): activated sludge SBR (ASBR) and granular SBR (GSBR). In synthetic young landfill leachate treatment, GSBR was more efficient in nitrogen and carbon removal than ASBR. During the steady period of the experiment, 99% total ammonium nitrogen (TAN) was removed through nitritation and nitrification in GSBR with an average influent TAN concentration of 498 mg/L. On the contrary, complete nitrification was not achieved in ASBR with a nitrification efficiency of 77±10%. GSBR also presented higher efficiency in denitrification and COD removal compared to ASBR. Phosphorus removal efficiency was almost identical in both reactors. Synthetic old landfill leachate treatment using GSBR maintained the stable COD removal efficiency at 66%, when the ammonia nitrogen to the maximum of 465±46 mg/L. The ASBR required a start-up of at least 30 days and removed 59±9% of COD when an influent ammonia nitrogen concentration about 200 mg/L. The GSBR was also more efficient than the ASBR for nitrogen removal. The granular sludge reached a maximum ammonia removal of 95±7%, whereas 96±5% was achieved by ASBR. The phosphorus removal was likely affected by the free nitrous acid (FNA) and the low biodegradability of tannic acid. In raw landfill leachate treatment, the total ammonia nitrogen (TAN) removal efficiency was in GSBR approximately 99.7%. However, the ASBR treatment did not show a consistent performance in TAN removal. TAN removal efficiency decreased with increasing ammonia concentration in the influent. Nitrification in GSBR was partially inhibited at FA concentrations of 48 to 57 mg/L, which was two times more than the FA concentration that inhibited nitrification in ASBR. In terms of chemical oxygen demand (COD) removal, low removal efficiencies of 17% and 26% were observed in ASBR and GSBR, respectively. The low COD removal efficiencies were associated with the refractory organic content of the leachate used in this study, which resulted in a poor phosphorous removal performance as well. Overall, aerobic granular sludge showed a better performance in removing nutrients and organic matter from young or old landfill leachate, being more efficient than the conventional suspended growth activated sludge. Therefore, the use of AGS for leachate treatment should be encouraged. Further investigations should also be addressed, especially with a focus on improving SND and phosphorus removal efficiencies. / May 2017

Dissertation submitted in compliance with the requirements for the Master's Degree in Technology: Biotechnology, Technikon Natal, 2001. / Up until now extensive work has been done to develop kinetic models and related software that can be used successfully to simulate and design nitrification denitrification (ND) and nitrification denitrification biological excess phosphorus removal (NDBEPR) systems for efficient nitrogen removal. The denitrification kinetics of these systems have primarily been determined and attributed to the ordinary heterotrophic bacteria, now also known as the OHO fraction, otherwise not involved in biological excess phosphorus removal. However, denitrification kinetics determined for ND systems have been found to vary considerably at times when applied to NDBEPR systems because of varying OHO active fraction estimates and the unexplained occurrence of anoxic phosphorus removal and anysuccess achieved to date has been some what fortuitous. Ultimately variations in process performance and kinetics are attributable to inadequate control and lack of understanding of the ecological, physiological and biochemical activities of constituent microorganisms. There is growing concern and movement towards a better understanding of the microbial community within activated sludge in order to gain optimal control of the process. / M

At least 60% of First Nation communities in Manitoba, including the Lake Manitoba First Nation, are in wetland areas.47% of First Nations communities in Manitoba served by facultative lagoons failed to achieve the total phosphorus (TP) concentration of 1 mg/L in proposed regulations for effluent discharge into the environment. The Lake Manitoba First Nation community facultative lagoon system treats domestic wastewater and seasonally discharges effluent into a wetland that connects to Lake Manitoba. This research was performed to estimate phosphorus removal efficiency through the natural wetland during the vegetation growing season.The average TP concentration reduction utilizing the natural treatment area of 1.3 ha was more than 70%, achieving the desired total phosphorus below 1 mg/L.These short-term study results indicate the potential of natural wetland treatment applications under cold continental climate conditions, as an effluent polishing step to satisfy regulatory requirements for phosphorus reduction in smaller First Nations communities. / February 2017

Nitrite (NO2-) substrate under certain conditions can cause failure of N-removal processes relying on anaerobic ammonium oxidizing (anammox) bacteria. Detoxification of NO2- can potentially be achieved by using exogenous nitrate (NO3-). In this work, continuous experiments in bioreactors with anammox bacteria closely related to “Candidatus Brocadia caroliniensis” were conducted to evaluate the effectiveness of short NO3- additions to reverse NO2- toxicity. The results show that a timely NO3- addition immediately after a NO2- stress event completely reversed the NO2- inhibition. This reversal occurs without NO3- being metabolized as evidence by lack of any 30N2 formation from 15N-NO3-. The maximum recovery rate was observed with 5 mM NO3- added for 3 days; however, slower but significant recovery was also observed with 5 mM NO3- for 1 day or 2 mM NO3- for 3 days. Without NO3- addition, long-term NO2- inhibition of anammox biomass resulted in irreversible damage of the cells. These results suggest that a short duration dose of NO3- to an anammox bioreactor can rapidly restore the activity of NO2--stressed anammox cells. On the basis of the results, a hypothesis about the detoxification mechanism related to narK genes in anammox bacteria is proposed and discussed.

Dissertations submitted in compliance with the requirements for the Master's Degree in technology: Biotechnology, Technikon Natal, 2001. / Hexavalent chromium [Cr(VI)] or chromate, is a toxic, water-soluble contaminant present in many soils and industrial eflluents. As a result of contaminated discharges from industrial applications, and inappropriate wastedisposal practices, significant amounts of chromate have found their way into the environment. This poses a health risk to man as well as animals and plants due to the carcinogenicity, mutagenicity, and teratogenicity of chromate. In man, acute, high level exposures to Cr(VI) can result in ulceration of the skin, eyes, and mucous membranes. Exposure of plants to Cr(VI) can result in reduced biomass production, and in extreme cases, death. Upon reduction ofCr(VI) to trivalent chromium [Cr(III], the toxic effects are significantly decreased because of a decrease in the solubility and bioavailability of Cr(III). Traditionally, Cr(VI) has been recovered from aqueous systems using processes exploiting the differential solubility properties described above. The use of chromate reducing bacteria represents a potential mechanism for the development of an efficacious, cost effective alternative to traditional chemical/physical processes for Cr(VI) recovery from the environment. Therefore, the aim of this research was to isolate and identify chromate reducing bacteria from soil, and characterise the chromate reductase enzyme in order to determine the potential of bacteria to detoxify chromate by reduction. Bacteria from soils and wastewater were examined for chromate reducing potential and identified on the basis of biochemical tests and API 20E. Organisms were isolated by the spread plate technique. Species of Pseudomonas maltophilia, Bacillus subtilis, Acinetobacter calcoaceticus, and Cellumonas cellasea were capable of catalyzing the reduction ofCr(VI) to Cr(IlI) in batch experiments. Reduction capability as high as 99% by the isolates was detected from an initial Cr(VI) concentration of 150 mg.L' in batch cultures. Chromate reduction was determined by means of the diphenylcarbazide method and total chromium was measured by atomic absorption spectroscopy. Pseudomonas maltophilia was observed to be the most suited organism for the efficient detoxification ofCr(VI) due to its wide temperature and pH requirements, low substrate utilization, and tolerance to heavy metal ions of'Cu', Cd2+,Zn2+,and Ni2+which commonly appear in industrial eflluents along with Cr(VI). Reduction rate in a batch reactor for this organism was calculated to be 1.75 mg.g+h'. Comparison of the rates of chromate reduction by Cr(VI) grown cells and cells grown without chromate indicated that the chromate reductase activity is constitutive. Reductase activity was detected by means of the lysozyme-EDTA method in aerobically grown cells, with highest specific activity in the cytoplasmic fraction of the cell. The Cr(VI)-reductase was found to be NAD(p)H-dependent and yielded an activity of 3.24 ml.I.mg' of protein in the cytoplasmic fraction. Once optimization of the parameters in the batch reactor was achieved, cells of Ps. maltophilia was immobilized into polyacrylamide gel and packed in a column. Mass balance studies indicated that ca 147 mg.L' chromate passing through the column undergoes reduction with an initial Cr(VI) concentration of 150 mg.L' resulting in a Cr(VI) reduction efficiency of98%. An amount of 0.11 mg.L' remained in the cells, 0.11 mg.L' in the cell wash water, and 1.65 mg.L' was unaccounted for in the mass balance. Chromate reduction rate in the continuous-upflow reactor system was calculated to be 5.34 mg.g'l.h', which was 3-fold higher than that calculated for the batch reactor. Chromium-contaminated industrial eflluent obtained from Sheffield, Natal, and Saayman Danks Electroplaters was pumped into the continuous-upflow reactor containing immobilized cells of Ps. maltophilia to determine the industrial applicability of the reactor to treat chromate-containing effluents. Complete Cr(VI) reduction / M

The focus of this work has been to quantify important processes for climatically relevant aerosols, and to improve our understanding of, and ability to accurately model, aerosols in the atmosphere on a large scale. This thesis contains five papers focused on different parts of the life cycle of atmospheric aerosol particles. Two papers describe the physical process of emission of primary marine aerosols. The large uncertainties in these processes are demonstrated by examining the diversity of existing parameterizations for emissions. Building from laboratory experiments to validation of model results with observations, new parameterizations are suggested. These take into account also effects of water temperature on primary marine aerosol production. In the third paper the main focus was to develop a new aerosol wet removal scheme in the Lagrangian transport and dispersion model FLEXPART. Removal timescales and atmospheric concentrations are found to be close to observation based estimates. The final two papers focus on atmospheric black carbon aerosols at high latitudes. As an example of increased human activities in the Arctic, local emissions from cruise ships visiting the research base in Ny Ålesund had demonstrable effects on the level of pollutants measured there. In contrast, inland Antarctic air was shown to be clean compared to the Arctic, due to the extremely long transport time from any major aerosol sources. The work done in this thesis has addressed critical uncertainties regarding the aerosol lifecycle, by better constraining aerosol emissions and atmospheric lifetimes. The development of the new wet removal scheme has improved FLEXPART model accuracy, which will be beneficial in future applications of the model. / <p>At the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 3: Manuscript.</p>