Resumen
Palm Oil Mill Effluent (POME) is well known as a difficult waste to manage by mill operators due to the large quantity produced at a time. Previous studies by our group has revealed that Sub-critical water (subCW) was able to be used as batch pre-treatment of POME to hydrolyse large organic matters in POME into smaller water-soluble molecules (sugar etc.). However, the batch process has disadvantages which pressure cannot be manipulated. This research is thus conducted in continuous mode and POME?s recovery of edible oil was investigated. POME samples were subjected to the continuous sub-critical water treatment at various reaction temperatures ranging from 190 °C to 250 °C with different pressure within 10 minutes. Three main phases were separated after the treatment: edible oil, aqueous and residual solid phases. The maximum yield of edible oil was achieved at 210 °C with 20 bars. The yield of total sugar (75.3%) in the aqueous phase was the highest at 190 °C with 10 bars. Yields of total sugar were due to the decomposition of hemicelluloses and cellulose in POME. Yield of residual solid decreased as temperature and time increased because of the increased decomposition of organics. Consequently, the results showed not only the temperature, but pressure also brings significance for efficient subCW treatment.