HIGH-RATE AND COMPACT 2-STAGE POSTDENITRIFICATION PROCESS WITH SINGLE-SLUDGE PRE-DENITRIFICATION

For the sewage treatment plants near rivers and closed water bodies in urbanized areas there is a growing demand for introduction of advance d treatment processes for nitrogen and phosphorus removal for water qu ality conservation and environmental protection. In order to achieve t he total nitrogen content of below 10 mg/L in effluent, a compact sing le sludge pre-denitrification process by dosing immobilized pellets in the nitrification tank (PEGASUS process) has been already developed ( Tanaka et al. 1992). Furthermore, a two-stage PEGASUS process and a PE GASUS process with post-denitrification were developed and investigate d for nitrogen removal. Both processes achieved the total nitrogen of less than 5mg/L. Copyright (C) 1996 IAWQ.