A.A.L.Zinatizadeh - School of Chemical Engineering Campus, University Sains Malaysia
A.R.M.Mohamed - professor
M.D.Mashitah
A.Z.Abdullah

An up-flow anaerobic sludge fixed film (UASFF) bioreactor was to treat the pretreated palm oil mill effluent (POME) . In physical pretreatment, POME was pre-settled for 2h and the supernatant was fed into the reactor. In chemical pretreatment , optimum dosages of cationic and anionic polymers were used. Experiments of pretreated POME digestion were conducted based on a central composite face – centered (CCFD) with two independent operating variables, feed flow rate (QF) and up-flow velocity (Vup) . The operating variables were varied to cover a wide range of organic loading rate (OLR) from 3.8 to 29 g COD /l.d Four dependent parameters were measured as response factors. These parameters were total COD (TOCD) removal, effluent total volatile fatty acid (TVFA), effluent bicarbonate alkalinity (BA), and methane yield (YM) . Associate stable TCOD removal efficiency of 83.5% was achieved at the highest QF (3031 l/Department, corresponding to OLR of 26g COD/ld) for pre-settle POME whereas only 62.2% TCOD removal was achieved with chemically pretreated POME at QF of 7.636 l.d (corresponding to OLR of 29 g COD/l.d) and that too was coupled with prosess instability . The highest level of yield was 0.34 and 0.33 for pre-settled and chemically pretreated POME , respectively , where QF and Vup were 1.01 and 0.2 m/h, respectively . The obtained results provided valuable information about interrelations of equality and process parameters at various operating conditions and also showed effects of suspended solids on the reactor performance.

POME , Pretreatment , UADFF reactor , Central composite face- centred design (CCFD)