Efficiency Increase of Water Treatment Plants in Rwanda

摘要

The drinking water for the urban areas of Rwanda is mainly produced from surface water. The water of rivers and lakes is often characterized by high turbidity, especially during the rainy season. To remove the turbidity chemicals are required in the flocculation process. The high demand for such chemicals can be significantly reduced by the choice of chemicals and their optimised application. Furthermore the extended use of groundwater allows an additional reduction. The use of surface water of highturbidity requires high dosing of coagulant, normally aluminium sulphate, to get well sedi-menting floes that enclose the small mineral particles of the raw water. When turbidity rises during the rainy season to values higher than 1,000 NTU (nephelometric turbidity units) coagulant dosing must be equally high. Due to the acidic reaction of aluminium salts pH is to be stabilized by dosing of lime.