| dc.description.abstract | Palm oil mill effluent (POME) is a highly polluting wastewater that pollutes the
environment if discharged directly due to its high chemical oxygen demand (COD) and
biochemical oxygen demand (BOD) concentration. In addition, anthropogenic release of
greenhouse gases, especially carbon dioxide (CO2) and methane (CH4) from POME
anaerobic degradation process has been recognized as one of the main causes of global
warming. Thus, this study aims to discuss the COD removal efficiency, behavior of volatile
fatty acid (VFA) and efficiency of biogas production in the suspended closed anaerobic
reactor (SCAR) for the treatment of POME wastewater. The operation of this research
study was performed by a series of continuous experiments using feed flow-rates of 375
ml/d [run 1], 450 ml/d [run 2], 560 ml/d [run 3], 750 ml/d [run 4], 1125 ml/d [run 5] and
2250 ml/d [run 6] of the wastewater, which correspond to hydraulic retention time (HRTs)
of 12, 10, 8, 6, 4 and 2 days, respectively. The duration of the experimental runs 1, 2, 3, 4, 5
and 6 was 27, 15, 11, 18, 14 and 14 days, respectively. The results indicated that the COD
removal efficiency and the biogas production rates decreased from 87.08 % to 38.20 % and
from 3000 ml biogas/day to 604 ml biogas/day, respectively as HRT decreased. Meantime,
the VFA concentration increased from 11569.71 mg CH3COOH/L to 16956.00 mg
CH3COOH/L with a decrease in HRT. Moreover, the methane content and the CH4: CO2
fraction decreased from 24.05 % to 10.64 % and from 0.76 to 0.27, respectively with a
decrease in HRT whereas the carbon dioxide and hydrogen contents were increased from
31.45 % to 39.63 % and from 4.35 % to 8.15 %, respectively, with a decrease in HRT.
These were attributed to variation of HRT that affects the system stability. | en_US |
