Main Article Content

Effect of pre-chlorination on the efficiency of iron and manganese removal from surface water by coagulation-flocculation using aluminium sulphate: case of the Okpara dam in the Republic of Benin


D Zogo
LM Bawa
HH Soclo
G Djanéyé-Boundjou
D Atchekpe

Abstract

Okpara dam water contained significant amounts of iron and manganese that could be problematic for consumers. In this study, we perfected a deferrization and demanganization technique by coagulationflocculation
preceded by chlorination. The maximum iron and manganese concentrations varied from 30 to 50 mg/L and 1.5 to 4.5 mg/L respectively before treatment. Purification yields depended on the conditions of operation. Under the least favourable conditions (coagulation at free pH), the removal yields varied from 10 to 73% for iron and from 2 to 24% for manganese. Under the best conditions (pre-chlorination and coagulation at pH 6.5), we obtained between 50 and 95% elimination for iron and 20 and 45% for manganese. The treatment was therefore little adapted for the removal of manganese.

Journal Identifiers


eISSN: 1997-342X
print ISSN: 1991-8631