Application of cement kiln dust enhancing methane production using upflow anaerobic sludge blanket reactor for the treatment of palm oil mill effluent

Abstract

Anaerobic digestion of palm oil mill effluent (POME) for continuous biogas production has been carried out in an upflow anaerobic sludge blanket reactor (UASBR) using cement kiln dust (CKD). POME is used as the substrate carbon source and CKD as a neutralizing agent. The effects of the hydrualic retention time (HRT) 20 h and organic loading rate (OLR) 4.5 kg COD/m³h^-1 over 95% COD removal and 0.89 mL CH₄/L/h with a methane yield of 0.65 L CH₄/g COD_removed at 1600 mg/L CKD in UASBR have been studied. Without CKD (control) the reactor for the removal of COD only 10.5% and methane production up to 0.13 L CH₄/g COD. However, increasing the OLR to 4.5 kgCOD/m³h^-1 by reducing the hydraulic retention time (HRT 6 h) reduced the COD removal efficiency to 58% and methane production up to 0.43 L CH₄/g COD_removed. Considering this, the use of CKD containing UASBR might be practically and economically attractive for industrial scale biogas production and sludge reduction from industrial wastes and wastewater.