Eighty percent of all biologically treated waste waters in Europe are oxidised by the activated sludge process. Bulking sludge caused by the proliferation of filamentous organisms is the primary cause of failure of this system. The effect of various substrates in both laboratory scale, fully mixed and sequencing batch (SBR) reactor configurations were used to assess their combined effect on activated sludge microbial ecology and hence sludge settlement. Five different substrate types were used ; synthetic sewage, a basic monosaccharide, disaccharides, polysaccharides and amino acids. In all cases using the fully mixed reactor, bulking occurred while, good settling sludge was produced in the sequencing batch reactor. The cause of this bulking was deemed to be due to the lack of so called "selector effect" within the fully mixed reactor characterised by :- i) high rates of substrate consumption ii) high oxygen (or generally: electron acceptor) up take rate iii) enhanced growth of zoogleal bacteria iv) increased metabolic diversity This laboratory work was compared and contrasted with a pure oxygen activated sludge (VITOX) system treating a high strength pea processing waste water. This fully mixed system had proved difficult to operate since its installation and in the first two years of this study suffered bulking caused by low dissolved oxygen levels. In the third year a combination of a hydraulic problem and subsequent lack of control led to filamentous bulking. This particular bulking incident was controlled by the addition of chlorine to the aeration tank which was selectively toxic to the filamentous organisms present. Due to the studies carried out at both laboratory and full scale an initial contact zone was installed within the main aeration tank prior to the 4th year of this study so as to create an area of high floc loading and high substrate uptake. This initial anoxic contact zone proved successful in preventing the development of a poorly settling sludge and is in line with common practice for the elimination of filamentous bulking reported in the literature. Oxidation Reduction Potential (ORP) proved a reliable and appropriate monitor of conditions of low to zero D.O. experienced in the laboratory scale reactors and at full scale in the anoxic contact zone. It was also found that ORP could be used to detect when D.O. levels became completely depleted and monitor reductions in nitrate levels.

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Chemical (gaseous) emissions from wastewater treatment plants (WWTP) are perceived as odour and can generate undesirable health reactions. These could affect the quality of life to those regularly albeit intermittently exposed, although regular exposure may result in tolerance and loss of recognition of the odour. Consequently, research is necessary to establish the role of Environmental Impact Assessment (EIA) in ensuring that facilities such as WWTP do not pose a threat to local communities, particularly in relation to housing developments for poor communities. The aim of this study was to investigate if the EIA regulations were effectively implemented before building of the Residential Development Proiect (RDP) houses at KwaMathukuza, in Newcastle South Africa. Furthermore, the study intended to determine the impact the (WWTP) has on the health of people who reside close to the site and to establish if the families staying close to the WWTP have any common ailments such as handicapped babies, early deaths within families. Findings would also indicate if RDP houses should be built in close proximity to such sites. Data was collected through a survey of 85 residents living within five kilometers and ten residing beyond five kilometers from the WWTP. The participants were selected randomly. Municipality employees who worked with the WWTP were also sampled together with healthcare givers. Data included information about health of the community, their perception of the gases released from the WWTP as well as EIA meetings and processes related to the construction of the RDP houses. The outcome of this study revealed that EIA regulations were not adequately implemented and that this residential site was unsuitable for the construction of RDP houses. It emerged that the residence regularly experience unpleasant odours released from the WWTP. These could be associated with ill-health of the residents as well as v degradation the environment in general. The study also found that the effect of the WWTP affects even those communities who reside beyond five kilometers from the WWTP. The researcher argues for more stringent mechanisms to ensure that EIA regulations are properly implemented to prevent adverse effects on the communities. / Environmental Sciences / M. Sc. (Environmental Management)

Chemical (gaseous) emissions from wastewater treatment plants (WWTP) are perceived as odour and can generate undesirable health reactions. These could affect the quality of life to those regularly albeit intermittently exposed, although regular exposure may result in tolerance and loss of recognition of the odour. Consequently, research is necessary to establish the role of Environmental Impact Assessment (EIA) in ensuring that facilities such as WWTP do not pose a threat to local communities, particularly in relation to housing developments for poor communities. The aim of this study was to investigate if the EIA regulations were effectively implemented before building of the Residential Development Proiect (RDP) houses at KwaMathukuza, in Newcastle South Africa. Furthermore, the study intended to determine the impact the (WWTP) has on the health of people who reside close to the site and to establish if the families staying close to the WWTP have any common ailments such as handicapped babies, early deaths within families. Findings would also indicate if RDP houses should be built in close proximity to such sites. Data was collected through a survey of 85 residents living within five kilometers and ten residing beyond five kilometers from the WWTP. The participants were selected randomly. Municipality employees who worked with the WWTP were also sampled together with healthcare givers. Data included information about health of the community, their perception of the gases released from the WWTP as well as EIA meetings and processes related to the construction of the RDP houses. The outcome of this study revealed that EIA regulations were not adequately implemented and that this residential site was unsuitable for the construction of RDP houses. It emerged that the residence regularly experience unpleasant odours released from the WWTP. These could be associated with ill-health of the residents as well as v degradation the environment in general. The study also found that the effect of the WWTP affects even those communities who reside beyond five kilometers from the WWTP. The researcher argues for more stringent mechanisms to ensure that EIA regulations are properly implemented to prevent adverse effects on the communities. / Environmental Sciences / M. Sc. (Environmental Management)