Winery wastewater was treated in two pilot-scale aerated lagoons operating in fed-batch mode. A first lagoon of 27.2 m(3) working volume was gradually filled with wastewater with an average COD content of 8700 mg/L. Given that with the flow-rate used (790 L/day) this first lagoon completed its working volume after 30 days of starting, part of the liquid contained in the first lagoon was transferred to another adjacent second lagoon of 10.8 m(3) working volume. Therefore, the experiment continued in the second lagoon for another additional 24 days using an influent with a COD content of 18,700 mg/L at a flow-rate of 170 L/day. After the 21st day, a maximum COD removal efficiency of 91% was achieved, and this value was maintained virtually constant until the end of the experiments. A mathematical model based on three differential equations solved simultaneously allowed the kinetic parameters of the system to be obtained. (C) 2009 Elsevier Ltd. All rights reserved.