The performance and kinetic study of membrane anaerobic system in treating POME

Abstract

The application of the three known kinetic models on MAS (membrane anaerobic system) process treating the POME and the overall MAS treatment efficiency were investigated. The MAS consists of a cross-flow ultrafiltration membrane (Model Micro 240) for solid-liquid separation. Six steady states were attained over a range of mixed liquor suspended solids of 12,681 - 30,460 mg/l. The study showed a good fitting of the Monod Model (91.1%), Contois Model (98.5%) and Chen and Hashimoto Model (95%) for the MAS treating raw POME at organic loadings between 1.5 kgCOD/m3/d to 6.5 kgCOD/m3/d. The growth yield coefficient, Y, was found to be 0.604 kg VSS/kgCOD while the specific microorganism decay rate was 0.099 day-1. The k values were in the range of 0.242 to 0.425 mg COD/mg VSS.d and the μ(m) values were between 0.145 to 0.257day-1. Throughout the study, the removal efficiency of COD was 83.2 to 97.97 %. The methane production rate was between 0.262 to 0.473 l/g-COD-utilised/d. The MAS treatment efficiency was greatly affected by SRT and OLRs. In the study, membrane fouling and polarization at the membrane surface played a significant role in the formation of the strongly attached cake layer limiting membrane permeability.