Estimation of Melanoidin concentration in palm oil mill effluent ponding system and its treatment using Calcium Lactate

Abstract

Colour removal from wastewater is among the major challenge in water and wastewater treatment. Among others, melanoidin could be the source of colour in wastewater. In this study, the estimation of melanoidin concentration in conventional palm oil mill effluent (POME) ponding system was investigated. Melanoidin was analyzed by detecting its absorption using double beam UV-Vis spectrophotometer. For melanoidin, the maximum absorption is 330nm. From the analysis, the melanoidin concentration decrease from anaerobic pond 1 to anaerobic pond 3 and slightly increase in anaerobic pond 4 and aerobic pond 1. After that, the melanoidin concentration decreased from aerobic pond 1 to final discharge. It is estimated that the anaerobic pond 1 had the highest melanoidin concentration which was 87.3 mg/L. Finally, the effectiveness of melanoidin removal using a coagulation/flocculation process was also studied. Calcium lactate was used as a coagulant and low molecular weight anionic polyacrylamide was used as a coagulant aid. The jar test experiment was carried out by using 0.3g/L calcium lactate solution and dosage of anionic polyacrylamide was altered in order to find out the best melanoidin removal. Experiments carried out by using sedimentation time of 20 minutes showed that the highest percentage removal of melanoidin was 80.93% at the dosage of 0.3g/L of calcium lactate without any anionic polyacrylamide being added. This result concluded that the addition of anionic polyacrylamide as coagulant aids is not significant when compared to the use of calcium lactate only.