REMOVAL OF BENTONITE CAUSING TURBIDITY BY ELECTRO-COAGULATION

The efficiency of electro-coagulation as a turbidity removal process h as been investigated using bentonite as a turbidity source. The influe nce of certain operational parameters such as current input, contact t ime, electrolyte concentration, and initial turbidity on the coagulati on efficiency were studied. The process was found to achieve excellent turbidity removals. The lowest residual turbidities were 0.5 and 0.75 NTU for the samples with initial turbidities of 112 and 52 NTU, respe ctively. This was obtained at a current of 0.5 A a contact time of 5 m inutes, and a calculated dissolved iron concentration of 10.8 mg/l. At a constant current of 0.5 A a reduction in the contact time from 5 to 2 minutes in the case of turbidity level 1 (52 NTU) and from 5 to 1 m inute in the case of turbidity level 2 (112 NTU) resulted in better tu rbidity removals. The optimal operational parameters for turbidity lev el 1 are a current of 0.5 A a contact time of 2 minutes and an NaCl co ncentration of 2 g/l resulting in a calculated amount of iron generate d of 4.3 mg/l. However, for the case of turbidity level 2, the optimal values are a current of 0.5 A, a contact time of 1 minute and an NaCl concentration of 5 g/l with a calculated iron amount generated of 2.2 mg/l.