Anammox process was applied to remove nitrogen from pretreated brewery wastewater. Organic carbon removal and partial nitritation treatment were carried out by two stage pretreatment processes using a thread type acrylic fiber biomass carrier as the pretreatment of the sludge reject water of Asahi Breweries, Ltd. Plug-flow type anammox reactor, which is considered to be the smallest reactor volume and least driving power based on the theory of reaction engineering, was applied for the treatment of partially nitrified reject water. Malt Ceramics (MC), produced from carbonized spent grains were filled as a biomass carrier for anammox sludge. Results of this study indicate that the anammox process can operate under extremely HRT with low NH(4)-N concentrated wastewater. Maximum volumetric loading rate of 4.17 kg-N/m(3)/d was obtained under HRT of only 42 min. It is demonstrated that our invented anammox reactor can be operated even in high C/N ratio such as 0.196. The study has developed such a technology that would make anammox process very fast in a very small reactor.