Biological Performance of Palm Oil Mill Effluent (POME) Treatment using AnMBR

Abstract

Palm Oil Mill Effluent (POME) is an attractive medium for biogas production in an anaerobic membrane bioreactor (AnMBR) because of its high lipid content. Long-chain fatty acid (LCFA) accumulation is toxic and considered harmful for the biological performance within the reactor as they can be absorbed by biomass particles causing sludge flotation and biomass washout from the reactor. Membrane fouling can be caused by LCFA inhibition through adsorption on membrane walls. The biodegradation efficiency and filterability are affected by several factors such as solids retention time (SRT), and an organic loading rate (OLR). The objective of this research was to determine biological performance and LCFA inhibition while operating the AnMBR system at SRT of 90 days and an OLR of 3 g COD/ L/d under thermophilic condition (55 degrees Celcius).
It was observed that successful operation was achieved with high COD removal efficiencies over 98% and average biogas production of 5 NL/d. Acidification occur in the sludge causing signification drop in pH, biomass concentration and methane production. The reactor slowly recovered back normal after adding sodium bicarbonate in the VFA feed. In addition, acetic and propionic acid were the major VFA constituent presented in the sludge.