Poonsuk Prasertsan, Masao Ukita, and Monticha Pechsuth

pp. 771 - 777

Abstract

Palm oil industry is one of the three major agro-industries in Southern Thailand and generates large
quantities of effluent with high organic matter (BOD and COD values of 58,000 and 110,000 mg/l, respectively), total solids and suspended solids (70,000 and 40,000 mg/l, respectively), oil & grease (25,600 mg/l),
and has a low pH (4.5). Conventional anaerobic ponding system is normally employed in palm oil mills to
treat the effluent. To increase its efficiency, biopretreatment to remove the organic matter and oil & grease by
thermotolerant polymer-producing fungi was investigated. The palm oil mill effluent (POME) was treated
by the two thermotolerant polymer-producing fungi, Rhizopus sp. ST4 and Rhizopus sp. ST29, at 45ºC under
aseptic and septic conditions. Rhizopus sp. ST4 gave the same oil & grease removal (84.2%) under both conditions but COD removal under septic condition (62.2%) was 8.8% higher than that under aseptic condition
(53.4%). On the contrary, Rhizopus sp. ST 29 under aseptic condition showed 11% and 25.4% higher oil &
grease removal (91.4%) and COD removal (66.0%) than those under septic condition. Comparison between
the two isolates under aseptic condition revealed that Rhizopus sp. ST29 exhibited higher oil & grease removal (91.4%) as well as COD removal (66.0%) than those of Rhizopus sp. ST4 (84.2% and 53.4%, respectively).
Under septic condition, Rhizopus sp. ST4 gave higher oil & grease removal (84.2%) and COD removal (62.2%)
than did Rhizopus sp. ST 29 (80.5 and 40.6%, respectively).