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.

Stormwater provides a direct link between urban infrastructure and the urbanised natural environment. In particular, highway drainage presents a high risk of pollution when compared to other urban land use areas (Ellis et al., 2012); introducing heavy metals, suspended solids and hydrocarbons to urban waterways. This research investigated runoff from the R300 highway, located in the greater Cape Town area. The City of Cape Town Management of Urban Stormwater Impacts Policy requires the treatment and attenuation of stormwater from developments within the city, and proposes Sustainable Drainage Systems (SuDS) as a means to achieve this (CSRM, 2009b). SuDS are structural and process controls that attenuate surface drainage, improve runoff water quality, provide amenity and deliver ecosystem services. This study characterized the R300 runoff through a sampling program and modelling exercise in order to provide an indication of the ability of SuDS to manage highway runoff in South Africa. Sediment and runoff samples were collected from the road surface and an undeveloped parcel of land adjacent to the highway. The sampling results showed that heavy metals, suspended solids and phosphorus are present in significantly greater concentrations in road runoff compared to rainwater from the same area. The concentration of aluminium, copper, lead, zinc and phosphorus exceed the Department of Water and Sanitation's water quality guidelines for aquatic ecosystems in excess of 1000%. The concentration of heavy metals, phosphorus and fats, oils and greases was significantly greater in road sediment compared to sediment from the surrounding area. Barring copper, all contaminant concentrations in the road surface sediment are less than the maximum concentration required to protect ecosystem health. The R300 rainfall-runoff response was modelled in PCSWMM to evaluate the performance of SuDS such as infiltration trenches, bioretention areas and swales for managing highway runoff in terms of quantity and quality. The modelling exercise showed SuDS to be a viable means to attain the City of Cape Town's stormwater objectives, provided that SuDS are implemented in treatment trains along the entire road length.

The critical situation in the water sector continues to jeopardize developmental principles and undermine strategies for poverty eradication. On the assumption that the failure in service provision can be largely attributed to an inability to holistically address all aspects of urban water management, a systems approach was used to develop a relevant and robust sustainability index which assesses the capacity of a city or a portion thereof to be sustainable. This thesis details the process of developing the Sustainability Index (SI) for a multidimensional assessment of urban water systems. In this research, an analysis of the current problems facing developing cities, particularly in Sub-Saharan countries, was undertaken. This was done so as to provide some insight into the current developmental issues hindering sustainable development. An examination of the urban water cycle was also carried out to illustrate the links within the cycle and between the various water uses and services. A process model was developed which addresses the multi-dimensionality of sustainability and the dynamism of urban water systems. This model combines aspects of the iterative procedure for assessing environmental sustainability introduced by Lundin et al. (2002) with the step-wise process proposed by Nardo et al. (2005).

The Bill of Rights in the Constitution of South Africa mandates the promotion of human dignity, equality, and freedom. To attain these three mentioned aspects, the Bill of Rights stipulates that every person has the right to safe water and sanitation and this is done to improve the welfare of every citizen. South Africa has approximately 13% (7.27 million) of its population staying in informal settlements. Most of these informal settlements were formulated during the land invasion and so on and has since been increasing throughout South Africa. This study sought to assess whether informal dwellers have access to safe water and sanitation, what is the state of the water and sanitation facilities. The assessment was conducted in terms of the Bill of Rights in the Constitution of South Africa and WHO. Marikana informal settlement in Cape Town was used as a case study. Safe water and sanitation to all remain a challenge in South Africa, notwithstanding the commendable efforts since 1994, to provide access to safe water and sanitation as a right to all people. Based on empirical findings and analysis of relevant documents, the study views the water and sanitation in SA informal settlements as unsafe. The sanitation facilities are inadequate thus contributing to existing open defecation. The coverage of the water and sanitation facilities is not enough, therefore, compromising the right to access safe water and sanitation. The findings show evidence of non-operational water supply infrastructure. The uncleanliness of the existing sanitation facilities contributes to health issues like water-borne diseases. The sanitation facilities lack the human right factor, for an example, facilities are not designed to accommodate the elderly and physical disable people. Though South Africa made commendable progress in providing access to water and sanitation nationally, the inequality in the provision of safe water and sanitation exists; there is lack of freedom due to the poor safety of public facilities and overcrowded settlements, and the protection of human dignity is still an issue in informal settlements. In general, while the study identifies the existence of comprehensive national legislative and policy frameworks in support of providing safe water and sanitation in informal settlements, there are various challenges such as availability of land, inadequate housing, policy implementation, infrastructure maintenance and so on, that hinder the right to safe water and sanitation and has a possibility to hinder the fulfillment of South Africa's vision 2030 goal to provide access to piped water and flush toilets by all people.

No description available.

'Water stress' is a term used when the pressures of urbanisation and the uncertainty of climate change on hydrological limits and capacities can no longer be overcome by traditional supply-oriented engineering responses because of their economic and environmental costs. It can be argued that the key alternative water policy responses are occurring with the changing role of development and Catchment Management Planning (CMPg) to a more 'catchment consciousness' water management model. In England and Wales the emergence of 'water stress' in the 1990s has coincided with the national launch of CMPg and renewed interest in development and water issues. Thus the research question sought to investigate how the National Rivers Authority (NRA) as a statutory environmental agency sought to improve and integrate river management by extending its influence to development planning through Catchment Management Planning (CMP) between 1991 and 1996. The particular areas of outcome focused on were water quality improvement, water resource management and flood protection, major NRA functions. The research findings demonstrated that there were different types of development response linked to water issues, scale of implementation and potential contribution to city form. The most important factor in the type of response was the water issue, with the flooding relationship being most advanced and water resources the least. The CMPg process assisted by supporting the promotion of water policies in DPs and creating a new context (involving stakeholder involvement and consensus building) in which to implement these policies. CMPg was found to be having the greatest impact in areas where no previous consensus over particular water issues had existed, and thus had begun to act as a new arena for debate on the problems and solutions required.

No description available.

No description available.

The agricultural sector and communities in the lower Red River Valley in Manitoba have suffered a number of water related problems since the Basin was first settled. Initially a massive drainage system had to be constructed to render much of the area suitable for agricultural production. Major floods and droughts have also plagued the area, resulting in direct measurable costs to area residents and businesses. In a more direct manner, the development of the area has been adversely affected by limited supplies of potable water, and due to a lack of irrigation water, the area has not been able to realize its full development potential. These problems became particularly acute between 1965 and 1980. During this period major Red River floods occurred in 1965, 1966, 1969, 1974, 1975, 1978 and 1979. In the sixty-five years previous to this period, there were only three major floods. Major drought occurred most recently in 1973, 1974, 1977 and 1980. Inevitably there was a public outcry for senior levels of government to initiate preventive action rather than merely providing compensation for losses. However, government has been slow to respond resulting in public frustration and disaffection. This study can be divided into three sections. The first four chapters deal primarily with the history of water management, tracing the evolution of policy and attitude, the transfer of responsibility from local government to more senior levels of government, and the evolution of institutional and methodological obstructions to resolving some of the recurring water management problems. The next four chapters examine the current situation in terms of potable water supply, the advantages and disadvantages of large scale irrigation and the controversy over solutions to flooding. The last chapter is comprised of a summary and recommendations. A common theme throughout the paper is the fact that regional economic development is the ultimate goal of water management. However, policy decisions seem to have devolved from the elected representatives of the people to the technocrats, thereby limiting public recourse to unsatisfactory decisions. The technocrats' approach has been to disassociate development from water management due to an over-reliance on benefit-cost analysis of site-specific, problem-specific issues. In view of the fact that public input is limited and the public perceives government action as wholly inadequate, this paper seeks to empower people to act.

No description available.