The aim of the present study is to evaluate adsorption capacity of regenerated spent bleaching earth, to decolourise and reduce the biological oxygen demand (BOD) of final discharged of palm oil mill effluent (POME). Different types of spent bleaching earth were used in this study, regenerated using acid and heat treatment after de-oiling (RDSBEAH), spent bleaching earth (SBE), de-oiled spent bleaching earth (DSBE) and new bleaching earth (NBE). Prior to the study, samples were characterised for their surface area, pore volume and functional groups. RDSBE-AH was found to have the highest surface area and pore volume when compared to the other three types of clays with values of 122.3 m2 g-1 and 68 cm3 g-1, respectively. For the decolourisation of POME, RDSBE-AH exhibited higher efficiency than NBE. Higher BOD reduction efficiency was found for NBE as compared to RDSBE-AH. The results demonstrated that the regenerated SBE, activated using combined acid and heat treatments, capable to decolourise and reduce the BOD of the POME final discharge, to comply with the stringent new proposed limits by Department of Environment (DOE).
Keywords: palm oil mill effluent (POME), regenerated spent bleaching earth, adsorption, biological oxygen demand (BOD), decolourisation