Natural plant materials as coagulant and flocculants for the treatment of palm oil mill effluent

Abstract

The present study reports the effectiveness of natural plant materials - fenugreek as a coagulant, with okra and Aloe vera as flocculants, to treat palm oil mill effluent (POME). The treatment process was modelled using Central Composite Design (CCD) of the Design Expert software. Standard jar tests were used to determine the important treatment parameters such as pH, coagulant dosage and flocculant dosage on the removal efficiencies and they were optimized with Response Surface Methodology (RSM). The optimum condition obtained from RSM was established for pH, coagulant dosage and flocculant dosage as pH 4, 22.24 g/L and 16.77 mL/L respectively for fenugreek-okra, and pH 4, 24.13 g/L and 20 mL/L respectively for fenugreek-Aloe vera. Removal efficiencies of TSS, TUR and COD were 88.19%, 78.35% and 30.56% respectively for fenugreek-okra and 83.40%, 82.78% and 32.95% respectively for fenugreek-Aloe vera. Results obtained from characterisation shows that the coagulation – flocculation process was ruled by inter-particle bridging as the dominant mechanism.