Anaerobic treatment of wastewater with high organic content using a stirred tank reactor coupled with a membrane filtration unit

Using a cross-flow membrane bioreactor, high anaerobic conversion rates of three different types of wastewater with varying organic content were achieved. Loading rates obtained were as follows: 20g CODL-1 d(-1) for artificial wastewater, approximately 8g CODL-1 d(-1) from vegetable processing industry (sauerkraut brine) and 6-8 g COD L-1 d(-1) for wastewater from an animal slaughterhouse. At stable conditions, COD-removal rates in all three wastewaters were higher than 90%. Methane yields from the treatment of artificial wastewater, sauerkraut brine, and animal slaughterhouse wastewater were in the range of 0.17-0.30, 0.20-0.34, and 0.12-0.32L(n) g(-1) COD-1 fed, respectively. The complete retention of biomass and suspended solids is a unique feature of this treatment process, which combines a high loading capacity and at the same time, high COD removal rates even for complex wastewater containing high concentrations of particulate matter. (C) 2002 Elsevier Science Ltd. All rights reserved.