Thesis (M.P.A.)--University of Hong Kong, 1997. / Includes bibliographical references. Also available in print.

M.Sc. / The South African Water Act (Act 54 of 1956) was promulgated in 1956. Section 21 of this Act required the permitting of all effluent dischargers, including sewage works. The General and Special Standards were subsequently published in the Government Gazette in 1984 in accordance with this Act, which set effluent discharge quality limits for such discharges. This was the Uniform Effluent Standard approach. However, this approach did not take into account the assimilative capacity of the receiving water, or limitations thereof. This resulted in a decrease in the water quality in the nations' water resources (DEAT 1999). The White Paper on Water Policy in South Africa was published by the Department of Water Affairs and Forestry in 1997. This paper identified this concern and suggested a change in the way water quality was managed in the country. The National Water Act (Act 36 of 1998) was subsequently promulgated in 1998, and provided the tool to effect these changes. This Act adopted the Receiving Water Quality Objectives (RWQO) approach. This approach takes into account the impacts on the receiving water as well as the impacts on other water users. This mini-thesis compared SA legislation regulating the discharge of wastewater, and more specifically sewage effluent, into the environment, by comparing it to first world legislation performing the same function. The effectiveness of the implementation of the SA legislation was also investigated. This study concluded that the promulgation of the National Water Act of 1998 (Act 36 of 1998) brought SA legislation on par with first world trends. This is an advanced piece of legislation, the effects of which are only now beginning to be felt. Much of the changes required by this Act are still being initiated and may take years to fully implement. Most dischargers still have valid permits issued in terms of the Water Act of 1956 (Act 54 of 1956), and these permits must be replaced by licenses issued in terms of the National Water Act of 1998 (Act 36 of 1998). An important conclusion from this study is that the legislation is not prescriptive in terms of specifying discharge license conditions, but instead allows the relevant authority, the Department of Water Affairs and Forestry to adjust the stringency of such licenses to suite the degree of impacts resulting from such discharges. Discharge licenses are therefore very site-specific and tailored to suite the type of discharge and impacts on the receiving water and other water users. In this way the requirements of all water users, including the aquatic ecosystem of the receiving water body, are taken into account, and protected. One suggested improvement to the SA legislation however, is to regulate industrial dischargers to sewer using national legislation. This is currently regulated by the by-laws of the relevant local authority, but is often insufficient to protect the sewage works and ensure the proper functioning of these works, which is largely dependant on the quality of raw sewage intake. Further research is required to determine the impact of industrial dischargers to sewer, and investigate how to regulate such discharges using national legislation. This study additionally assessed the implementation of SA legislation and the effectiveness of control over sewage dischargers. Enforcement of this legislation is not necessarily uniform, since much of the responsibility to enforce discharge permits and licenses lie with various officials within the Department of Water Affairs and Forestry. One way to ensure uniformity would be to require regular auditing by higher levels and management within this Department. Another important aspect of enforcement of these permits and licenses is that all permit and license holders, including Local Authorities, should be treated in the same way.

published_or_final_version / Civil and Structural Engineering / Master / Master of Philosophy

Domestic waste water from toilets, showers, garbage grinding, and kitchens was characterized in terms of waste concentration and volume in order to formulate four representative synthetic domestic wastes. The synthetic waste formulations were used to simulate concentrated domestic wastes flowing from dwellings whose water use has been reduced by the use of water saving devices such as low flow toilets and showers. Biological treatment of wastes with Chemical Oxygen Demands (COD) of up to 1500 mg/1 using activated sludge was investigated with both bench scale batch and continuous processes. Specific items investigated as functions of waste concentration included substrate removal rates, oxygen uptake rates, aeration properties, sludge settling, sludge aeration time, and aeration tank turbulence. Substrate removal rates were not enhanced by increasing domestic waste concentrations although oxygen uptake rates did increase slightly due to possible differences in sludge yield. The minimum sludge aeration time was found to be between 12 and 16 hours per day. Increasing mixing intensity in the aeration tanks reduced sludge settling ability without significantly improving the substrate removal rate. Aeration properties of systems treating wastes at 1500 mg/1 COD were found to be inferior to those of systems treating wastes at 750 and 250 mg/1 COD. No significant differences were observed between systems treating 250 and 750 mg/I COD wastes. Results indicate that reducing the flow of water from domestic residences reduces treatment costs only so far as that afforded by the reduction in clarifier size and pumping costs.

No description available.

No description available.

No description available.

Call number: LD2668 .P7 1974 P35

Digitized by Kansas Correctional Industries

Digitized by Kansas Correctional Industries