Biological nitrogen and phosphorus removal from brewery waste water.

Eyben, D., Gerards, R. and Vriens, L.

Abstract
A two stage brewery effluent treatment system is described. The first stage is a fairly conventional anaerobic treatment (acidification followed by methanogenesis), while the second is primarily aerobic but involves periods of anaerobic conditions. It takes place in a tank divided into three compartments. The central compartment is permanently aerated, while each of the other two is aerated in turn while sedimentation takes place (under anaerobic conditions) in the other. The effluent flows into whichever side compartment is being aerated and out at the other end. Nitrifying bacteria oxidize ammonium ion nitrogen to nitrite and then nitrate during the aerobic phase, then other bacteria reduce the nitrite and/or nitrate to nitrogen gas under the anoxic or nearly anoxic conditions of the sedimentation phase. A third group of bacteria, which are only active under aerobic conditions but can survive short periods under anaerobic conditions, remove phosphorus which they store in the form of polyphosphates. In trials, about 80 to 90% of the original COD of the effluent was removed during the first (anaerobic) stage and most of the rest in the second stage, which also eliminated 90 to 99% of the nitrogen content. About 97% of the phosphorus content of the effluent was also removed.
Keywords : aerobic anaerobic brewery effluent treatment nitrogen content phosphorus removal