Coagulation/Flocculation and Aerobic Treatment of Fenton Pre-Treated Phenalkamine Condensate

Abstract

Phenalkamine is a curing agent produced by the reaction of cardanol, paraformaldehyde, and amine. It has high pH, high COD (Chemical Oxygen Demand), low BOD/COD ratio. In this study coagulation/flocculation and aerobic treatment of Fenton pre-treated Phenalkamine condensate (having COD of 1,50,000 mg/l ) was investigated.The optimum operating conditionin the Fenton's oxidation stage was pH-3.5, H₂O₂/COD ratio-1and Fe^2+/H₂O₂ -1/30 and achieved COD removal efficiency was 80%. Fenton treated Phenalkamine condensate was subjected to  coagulation-flocculation (CF)  by using different coagulants like alum, ferrous sulphate, ferric chloride and polyacrylamide (anionic polymer) and the removal of COD at optimum dose of alum (200 mg/L), ferrous sulphate(200 mg/L), ferric chloride(300 mg/L) and polyacrylamide(150 mg/L),  were 43.40%, 32.35%, 35.29% and 47.05% respectively. Fenton treated Phenalkamine condensate was diluted and fed toaerobic reactors operated under different hydraulic retention time (HRT-2d,5d,10d) with 3500 mg/l MLSS (Mixed Liquor Suspended Solids). 10 d HRT was found to be suitable for the treatment and the average COD removal efficiency was 75%. Fenton’s oxidation followed by coagulation/flocculation or aerobic treatmentis a feasible treatment technique for Phenalkamine condensate