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1 octobre 2020
- handle: 10670/1.riccdj
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eutrophication water hyacinth cyanobacteria sediments algae lime ferric chloride aluminium chloride ferrous chlorideSujets proches
Quicklime Calcium oxide Hydrated lime Calcia Hydraulic limeCiter ce document
KPT Atta et al., « Chemical phosphate removal from Hartbeespoort Dam water, South Africa », Water SA, ID : 10670/1.riccdj
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Phosphate is one of the major nutrients contributing to the increased eutrophication of lakes and natural waters. The feed water to the Hartbeespoort Dam amounts to 650 ML/d of mainly treated sewage. Phosphate levels in the dam water need to be lowered from the current 0.2 mg/L to less than 0.05 mg/L to control eutrophication. Chemicals such as iron(III), iron(II), aluminium(III) and lime can be used to precipitate phosphate as FePO4, Fe3(PO4)2, AlPO4 and Ca3(PO4)2, respectively. OLI software was used to identify the most suitable chemical for phosphate removal. It was found to be Ca(OH)2 as this only requires the pH to be raised to 9.5. FeCl3, FeCl2 and AlCl3 were found to be unsuitable due to the required pH and/or the extent to which they could remove phosphate. For lowering of phosphate levels from 0.2 mg/L (as P), the current concentration in the Hartbeespoort Dam water, to