Waste water management in a sugar beet factory: a case study of comparison between anaerobic technologies

The ACOR-l sugarbeet factory owns a waste water treatment plant which handles 2500 m3/d of medium strength wastewater (COD = 4000 mg/L). The system was designed to treat the excess wastewater from the beet transport circuit, some process streams, the sanitary waters and wastewaters from an alcohol distillery. The plant is based on two lagoons for equalization and pre-acidification of the waste, an Upflow Anaerobic Sludge Bed (UASB) reactor (efficiency > 97% soluble COD) and a small lagoon used for final polishing of the effluent. A pilot-scale Fluidized Bed (FB) reactor was run in parallel with the UASB reactor to assess the capability of the FB system. There were two runs in consecutive campaigns, where results showed very good efficiency in spite of very high loading rates and low hydraulic residence times achieved in the FB system.