Institute for Water Quality Studies |
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ASSESSMENT OF THE IMPLEMENTATION OF THE PHOSPHATE STANDARD AT THE BAVIAANSPOORT AND THE ZEEKOEGAT WATER CARE WORKSEXECUTIVE SUMMARY |
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Full text (40k) and graphics (280k) This report must be cited as: Hohls, B.C., Quibell, G., Du Plessis, B.J., and Belcher, T. (1998). Assessment of the Implementation of the Phosphate Standard at the Baviaanspoort and the Zeekoegat Water Care Works. Report No. N/A230/01/DEQ0797. Institute for Water Quality Studies, Department of Water and Sanitation, Pretoria, South Africa.
Background The Department of Water and Sanitation (DWAF) has long recognised eutrophication as one of the major factors affecting the quality of South African water resources (DWAF, 1986). A direct result of eutrophication is an increase in the overall productivity of a water body which may include an increase in algae and aquatic macrophyte biomass, and leads to other specific water quality problems. The quality of the water in the Roodeplaat Dam has long been a cause for concern and various complaints have been made relating to this. The Northern Province Regional Office of the DWAF, therefore, requested that a study be conducted to determine the water quality status of the impoundment, and that the compliance of the Baviaanspoort and the Zeekoegat Water Care Works (WCWs) to the 1 mg.l-1 phosphate standard should be evaluated. Eutrophication Management by Means of the Phosphate Standard Eutrophication management programmes have concentrated on reducing the total phosphorus load to water bodies since phosphorus is generally considered the most manageable of the nutrients, and there are proven and cost effective technologies for the removal of phosphorus from wastewater. An effluent standard of 1 mg.l-1 ortho-phosphate (hereafter referred to as the Standard) was, therefore, promulgated on 1st August 1980 by the DWAF as the first step in a long-term eutrophication control programme. Local authorities responsible for seven sensitive catchments were given five years to upgrade effluent treatment plants in order to comply with the Standard. The DWAF decided to grant local authorities exemption from the Standard for a further three years due to a downturn in the economy. Therefore, the Standard was only implemented in 1988. Objective The objective of this report is to assess the extent of compliance to the Standard at the Baviaanspoort and the Zeekoegat WCWs, as well as to assess the effect of possible further water quality management scenarios on ameliorating the eutrophication-related water quality problems in the Roodeplaat Dam. Discussion
Recommendations
List of co-workers
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