The evaluation for the degradability of chemical oxygen demand (COD) and biogas contents before and after closed tank reactor (CR) and open tank reactor (TP) were observed. COD reduction in the TP (maximum degradability rate of 60%) and CR (maximum degradability rate of 85%). The variation in CH4, volatile fatty acid (VFA) and total suspended (TSS) contents in the effluent was more pronounced in the first six months and found stable afterward. The maximum organic loading rate (OLR) of 11.5 g-COD l/d attained corresponded to 85% overall COD removal. However, there is study to degradability of COD and quantify the actual CH4 recover from the commercial scale wastewater treatment from TP and CR. The findings indicated that the CH4 content was between 49% TP which was lower than the value of 57% reported in TP. The lower VFAs were found in the CR because of variation of palm oil mill effluent quality and quantity from palm oil mill industry.
