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

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.

► High-rate anaerobic digestion (AD) of fruit canning and cheese-dairy wastewaters. ► AD occurred under a short HRT (0.5–1.6 d) and high OLR (17–19 g COD L−1 d−1). ► Modified Stover–Kincannon, second-order kinetic models applied to experimental data. ► These models predicted reactor performance with high correlation coefficient (>98%).