Mediated microbial sensors utilizing two different yeast isolates (SPT1 and SPT2) were developed for the estimation of biochemical oxygen demand (BOD). Measurements of glucose/glutamic acid (GGA) standard solution with potassium ferricyanide mediation resulted in linear ranges extending from the detection limits (i.e. 2 and 5 ppm BOD) to 100 and 200 ppm BOD for the SPT1- and SPT2-based sensors, respectively. The standard error of the mean (SEW for 10 ppm. BOD measurements was 10.1% (SPT1) and 3.9% (SPT2). Response reproducibility had 10.6% error between three identically prepared SPT1 sensors. Response times for concentrations of 20 ppm BOD were within 10 minutes. For pulp mill effluent, the detection limits were 2 (SPT1) and 1 (SPT2) ppm BOD, with SEMs of 3.6% and 14.3% for the SPT1 and SPT2 sensors, respectively. Based on the results obtained in this study, it is concluded that SPT2 is the more suitable biocatalyst for pulp mill wastewater analysis. / While 18S rRNA gene sequence analyses, including BLAST homology searches, have suggested that isolate SPT1 is a close relative of Candida sojae (99.8% homology), no close matches have been found for isolate SPT2. The closest match for SPT2 was to Candida krusei (76.0% homology). Evidence from biochemical tests, fatty acid analysis, and 18S rRNA gene sequence analyses, indicates that isolate SPT2 is a novel yeast species.

Processing of petrochemical compounds produces a large amount of wastewater. This wastewater consists of toxic (hazardous) materials that can not be discharged to the environment without treatment. As restrictive environmental constraints increase, new technologies are needed to treat those toxic materials before discharging them to the environment. Wet Air Oxidation (WAO) is one of these new methods. / This study casts light on the effect of initial pH on the WAO of benzene at different temperatures and pressures. It was found that at pH 6, a temperature of 260°C and a partial pressure of oxygen of 1.38 MPa around 97% degradation was achieved in one hour. When the initial pH was lowered to 4 more than 90% degradation was achieved at 220°C and PO2 of 1.38 MPa in only 15 minutes.` It was concluded that the higher the temperature the better the benzene degradation, and the faster benzene degradation has been obtained with the increasing partial pressure of oxygen. The main intermediates were acetic acid and formic acid. / Furthermore, it was found that the degradation of benzene can be further enhanced in the presence of phenol. The main reason can be attributed to the effect of the free radicals generated from the fast phenol degradation. A simplified pathway for oxidation of benzene was proposed.

Beach meiofauna were chosen as environmental indicators to investigate the impact of Illovo sugar by-products effluent. The effluent is pumped through a 20 cm diameter pipeline into surf zone at Sezela beach on the coast of KwaZulu-Natal, South Africa. Meiofaunal communities were considered appropriate indicators as they are relatively stable both qualitatively and quantitatively on a seasonal and year to year basis. Most meiofauna also do not have planktonic stages in their life cycles, respond rapidly to pollution due to their fast generation times, and they are often abundant with high species diversity in habitats which are subject to considerable natural physical and chemical fluctuations. In this particular study there was a specific concern about trace amounts of furfural in the effluent. Furfural has been used as the active ingredient in a product designed to kill parasitic nematodes in crop fields. A large proportion of the beach meiofauna consists of nematodes. Eight stations were sampled for meiofauna along the beaches at Sezela on 7 different occasions. Seasonal effects on meiofauna and meiofaunal recovery during the period when the factory was not pumping effluent to sea was assessed. Samples were taken on the following dates: 4 July 2000 (winter); 30 August 2000 (winter); 13 December 2000 (spring); 26 January 2001 (summer); 8 March 2001 (summer); 9 April 2001 (autumn); and 2 January 2002 (summer). PRIMER (Plymouth Routines in Multivariate Ecological Research) was used for statistical analysis and included various univariate indices such as species richness, species diversity and evenness. These indices were then analysed using one-way ANOVA to determine any significant difference between sites over the 7 sampling periods and between the different seasons. Clustering and Ordination multivariate analyses were carried out on the community data and physico/chemical data to determine community patterns and relate them to the effluent and environmental data. The Nematode/Copepod ratio was also calculated. Meiofauna were analysed at major taxa level, as well as to nematode feeding groups and harpacticoid copepod and annelid family level, to determine if analysis to major taxa level is adequate as an indicator of pollution impact. The analyses indicated a possible degree of impact at stations close to the effluent discharge when effluent was being pumped to sea and a recovery was noted at the station closest to the discharge when effluent was not being discharged and analysis was conducted to the major taxonomic rank only. No improved resolution was achieved by analysing some of the meiofaunal major taxa to family level or different feeding groups. The analysis of the Nematode/Copepod ratio was shown to correspond with the multivariate analyses, however, this ratio could not reveal the severity of the impact where both nematodes and harpacticoids i.e. total meiofauna had been reduced by adverse conditions. The physical and chemical variables that showed the greatest correlation with the meiofaunal community patterns were sediment grain size, dissolved oxygen and salinity. There was a very strong positive correlation between Kjeldahl nitrogen in the interstitial waters and total numbers of meiofauna. This and the relationship with salinity may have suggested other possible sources of influence such as enrichment from the three estuaries in the area as well as a storm water drain located 150m north of the effluent discharge. A seasonal effect was observed with increased meiofauna numbers in autumn, but this was possibly influenced by the periods when effluent was not being pumped to sea. / Thesis (M.Sc.)-University of KwaZulu-Natal, Westville, 2007.

Disposing of waste on land has been a method practiced by many countries because it is relatively inexpensive. This has led to the fast increase of landfilling option which is also due to increase of waste generation, resulting in the increase in the urgency of investigating cheap measures of treating wastewater (leachate) that is generated from landfills prior to its discharge to the environment. After the application of the process of nitrification using Sequencing Batch Reactor (SBR) such as is applied at Mariannhill landfill site, Durban, the treated leachate still contains high level of nitrate ranging from 500 – 2000 mg/ℓ, which greatly exceeds the discharge limit of 12 mg/ℓ. Ex-situ bio-denitrification has been used widely around the world in various technological applications (SBRs, anaerobic trickling filters, etc.) that generally employ expensive chemicals. Hence the need to investigate the removal of nitrates using in-situ biodenitrification processes using readily available carbon sources such as fresh commercial garden refuse (CGRraw) and composted commercial garden refuse (CGR10). Both carbon sources were mixed with waste that had been treated for 8 weeks (Cell 1) and 16 weeks (Cell 2). The aim of this study is to determine the viability of pre-treated general waste at different degrees of stability (carbon contents) as carbon sources for in-situ bio-denitrification in landfills. The focus was mainly on determining the suitability, the kinetics and the performance of the different substrate. The suitability of the substrates to perform denitrification was assessed based on the carbon content and carbon to nitrogen ratio in the substrate. On establishing suitability, the kinetic rate of denitrification was assessed for each substrate. The kinetics analysis was based on the time taken for full denitrification to occur and the concentration of the byproducts of the denitrification process such as Ammonia. Characterization tests were performed to determine the suitability of the substrates to be used as carbon sources for denitrification. In situ denitrification processes were simulated at smaller scale in the laboratory using anaerobic batch reactors, with biologically treated leachate and seeded Treated leachate from the Sequencing Batch Reactor. Batch tests were conducted at a nitrate concentration level of 500 mg/ℓ. The combination of 8 weeks treated waste with Fresh Commercial Garden Refuse (Cell 1 + CGRraw) and with Commercial Garden Refuse (Cell 1 + CGR10), respectively, provided the most suitable substrates for denitrification as they contained the highest carbon content as well as relatively high carbon to nitrogen ratio (C:N) . Although the 16 weeks treated waste together mixed with Commercial Garden Refuse (Cell 2 + CGR10) had the lowest C:N ratio, this could be due to a lack of homogeneity within the sample. The results of the batch tests confirms that 8 weeks treated waste (Cell 1) and 16 weeks treated waste (Cell 2) substrates were both too stable and contained too little carbon to attain full denitrification. In addition to the inability to attain full denitrification, Cell 2 leached out nitrate of approximately 500 mg/ℓ NO3-N back into the batch. The batch test results showed that the cells substrates augmented with CGRraw and CGR10 achieved positive results as full denitrification was achieved within a maximum of 7 days for Cell 1 and 14 days for Cell 2. / Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2011.

The constitutional democracy in South Africa, ushered in by the first democratic elections of 1994, has opened up opportunities for the rise of various issues that were previously marginalised. The current political dispensation, supported by new progressive legislation, has rendered reckless management of waste management unacceptable. As a result, the management of waste, particularly the dominant landfill site waste management facilities, has come under increasing scrutiny from civil society organisations, the public and affected communities. Whilst the new constitutional order has demarcated responsibility for the management of solid waste, reality indicates that in spite of various legislative attempts to ensure the institutionalisation of sound and integrated waste management, solid waste is still poorly managed by responsible authorities. It has also been evident that many municipalities in South Africa still rely on the problematic landfill sites as the dominant waste disposal facility, this despite the obvious environmental problems that land filling engenders. It has been noted that waste problems are still marginalised from the mainstream development initiatives of responsible municipalities. The poor management of solid waste and the negation of responsibility, as in the case in the Msunduzi Municipality, are indicative of the politics involved in the identification of policy issues that government attends to from the available pool of existing social concerns. The failure to find policy solutions to identified waste problems in the Msunduzi Municipality has provoked questions around how policy issues negotiate their way onto the government agenda. The biggest issue from a public policy perspective is how does government decide on which issues they will address amongst the numerous and equally pressing social problems that warrant government attention. Using Kingdon‟s agenda-setting theory, this dissertation found that problem definition, policy dynamics and political interests all play influential roles in the agenda status of social problems and whether they are addressed or not. As a result, the study argues that there must be positive interaction between the three, problem, policy and political streams, in order to produce a solution to the policy issues of waste management in the Msunduzi Municipality. / Thesis (M.Soc.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2011.

The constitutional democracy in South Africa, ushered in by the first democratic elections of 1994, has opened up opportunities for the rise of various issues that were previously marginalised. The current political dispensation, supported by new progressive legislation, has rendered reckless management of waste management unacceptable. As a result, the management of waste, particularly the dominant landfill site waste management facilities, has come under increasing scrutiny from civil society organisations, the public and affected communities. Whilst the new constitutional order has demarcated responsibility for the management of solid waste, reality indicates that in spite of various legislative attempts to ensure the institutionalisation of sound and integrated waste management, solid waste is still poorly managed by responsible authorities. It has also been evident that many municipalities in South Africa still rely on the problematic landfill sites as the dominant waste disposal facility, this despite the obvious environmental problems that land filling engenders. It has been noted that waste problems are still marginalised from the mainstream development initiatives of responsible municipalities. The poor management of solid waste and the negation of responsibility, as in the case in the Msunduzi Municipality, are indicative of the politics involved in the identification of policy issues that government attends to from the available pool of existing social concerns. The failure to find policy solutions to identified waste problems in the Msunduzi Municipality has provoked questions around how policy issues negotiate their way onto the government agenda. The biggest issue from a public policy perspective is how does government decide on which issues they will address amongst the numerous and equally pressing social problems that warrant government attention. Using Kingdon‟s agenda-setting theory, this dissertation found that problem definition, policy dynamics and political interests all play influential roles in the agenda status of social problems and whether they are addressed or not. As a result, the study argues that there must be positive interaction between the three, problem, policy and political streams, in order to produce a solution to the policy issues of waste management in the Msunduzi Municipality. / Thesis (M.Soc.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2011.

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