A waste water treatment includes a biological filtration tank, a nitritation tank, and an anammox tank. The biological filtration tank performs biological filtration as a pretreatment process with regard to influent waste water and removes solids and organic matters. The nitritation tank performs a nitritation process with regard to waste water flowing from the biological filtration tank and supplies an electron acceptor needed for removing the organic matter in the biological filtration tank by returning some of the waste water back to the biological filtration tank. The anammox tank performs an anaerobic ammonium oxidizing process with regard to the waste water received from the biological filtration tank and the nitritation tank.