Substrate removal kinetics in high-rate upflow anaerobic filters packed with low-density polyethylene media treating high-strength agro-food wastewaters

Abstract

The process kinetics for two upflow anaerobic filters (UAFs) treating high strength fruit canning and cheese-dairy wastewaters as feed were investigated. The experimental unit consisted of a 10-L (effective volume) reactor filled with low-density polyethylene media. COD removal efficiencies of about 80% were recorded at the maximum OLRs of 19 and 17 g COD L-1 d-1 for the fruit canning and cheese-dairy wastewaters, respectively. Modified Stover-Kincannon and second-order kinetic models were applied to data obtained from the experimental studies in order to determine the substrate removal kinetics. According to Stover-Kincannon model, Umax and KB values were estimated as 109.9 and 109.7 g L-1 d-1 for fruit canning, and 53.5 and 49.7 g L-1 d-1 for cheese dairy wastewaters, respectively. The second order substrate removal rate k2(s) was found to be 5.0 and 1.93 d-1 respectively for fruit canning and cheese dairy wastewaters. As both these models gave high correlation coefficients (R2 = 98-99%), they could be used in predicting the behaviour or design of the UAF. © 2012 Elsevier Ltd.