Effect Of The Organic Loading Rate On The Performance Of Mesophilic And Thermophilic Anaerobic Digestion Of Palm Oil Mill Effluent
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Date
2011-11
Authors
Chou, Kian Weng
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Publisher
Universiti Sains Malaysia
Abstract
This project investigates the performance of mesophilic and thermophilic anaerobic digestion of palm oil mill effluent (POME). First, the scum-sludge mixture was acclimatized at mesophilic and thermophilic temperature prior the start-up of anaerobic digestion. The rapid CH4 production under both temperatures implied the anaerobic bacteria well adapted to POME. Later, the effect of organic loading rate (OLR) on anaerobic digestion of POME was investigated. The performance of mesophilic and thermophilic digestions were similar when OLR was ≤ 4.0 g COD/L/day. The average biodegradability of POME in mesophilic and thermophilic reactors was 77.14 % and 80.35 % respectively. Thermophilic reactor is more efficient because its maximum CH4 production rate (1.940 L CH4/L/day) was 53 % higher than mesophilic reactor (1.267 L CH4/L/day). The methane yield coefficient (YCH4) observed in both reactors was decreased with the increase of OLR because of the gradual lost of biomass. The effluent substrate concentration (ST), volumetric substrate removal rate (F) and volumetric methane production rate (MV) could be predicted using the generalized kinetic model. The estimated bio-kinetic parameters (A, R, μm, Ks dan Bo) for mesophilic digestion is 0.0419, 0.1729, 0.0756 day-1, 0.2774 g/L and 0.322 L CH4/ g CODadded; for thermophilic digestion is 0.0342, 0.1428, 0.1130 day-1, 0.2610 g/L and 0.3136 L CH4/g CODadded. Low value of A implied the batch-fed systems are more suitable for the hydrolysis step in anaerobic digestion.
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Keywords
Performance of mesophilic and thermophilic anaerobic , digestion of palm oil mill effluent