In 1968, a direct water reclamation system from domestic sewage was pioneered in Windhoek, Namibia, to supplement the potable water supply to the city. This system went through a succession of modifications and improvements over the years, but consistently produced water of acceptable quality, as evidenced a comprehensive chemical, bacteriological, virological, and epidemiological monitoring. Now, in 1995, Windhoek is again facing a shortfall of potable water in the light of a population increase (growing at 6% to 8% per annum) and increasing water demand, and is currently extending the water reclamation system from the previous 4800 to 21000 m3.d−1, the maximum attainable. All the components of the reclamation system are being reviewed and re-analyzed; demand management, diversion of some industrial effluents, wastewater treatment, water reclamation, oxidation and adsorption technologies, blending of reclaimed wastewater with other sources, buildup of salinity, treatment costs, and monitoring and quality control strategies. The practical experience at Windhoek demonstrates that a direct wastewater reclamation system is a practical, responsible way of augmenting potable water supplies in arid regions, but that it requires comprehensive planning, training and on-going commitment for its continued success.
This paper reviews peer-reviewed research on leadership in Africa published from 1950 to 2009. The review has a dual purpose. On the one hand, it provides scholars with an entry point to the relatively large body of historical literature by means of a descriptive diachronic analysis of the literature. On the other hand, it also applies a synchronic analysis, and concludes with four interpretative statements on the scholarship on leadership in Africa. These statements are: (i) Scholarship on leadership in Africa has changed, and the change is lopsided; (ii) Female scholars are increasing, and they work on different themes from male scholars; (iii) Legitimacy remains a key issue, and continues to evolve; (iv) Authenticity has become a key issue and is now closely related to reclaiming African values.
This paper deals with the occurrence of Giardia and Cryptosporidium in the water sources available for the Goreangab Reclamation Plant (GRP) and the subsequent removal during treatment at the reclamation plant. Giardia is detected more often than Cryptosporidium. 60% of the time it is detected in the samples from the dam and in 55% of the samples from the maturation pond effluent.
During the investigation, Giardia was detected in the final water 5% of the time and Cryptosporidium 2% of the time. The maximum Giardia cysts detected in a sample was 30, the 99% percentile was 20 and the 97% percentile 10 cysts. A maximum of 20 Cryptosporidium oocysts was detected in a sample. The 99% percentile counted 6.2 oocysts and the 97% percentile 0 oocysts.
From the data presented it is clear that the polluted dam water has the same risk level of Giardia and Cryptosporidium pollution as treated wastewater effluent. This emphasises the fact that the sources should be monitored continuously for these parasites. The sporadic high counts of Giardia and Cryptosporidium in the raw water sources indicate that a multiple-barrier approach must be followed to ensure the safe operation of even conventional treatment plants using polluted source water.
No correlation could be found between cyst and oocyst removal and other water quality parameters.
The advocating of a final water turbidity of 0.1 NTU and the use of particle counters can only be supported by these findings, as it is possible to achieve a turbidity of less than 0.1 NTU at the sand filter outlet, even in a developing country like Namibia. The challenge lies with the maintenance of equipment and vigilance of the operators.
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