The simultaneous removals of organics and nitrogen by means of the activated sludge process with a single reactor under contineous aeration and completely mixing have been investigated. In this reactor, the complex multireactions proceed simul taneously and therefore the substrate removal efficiencies are affected by the various factors. pH and DO are proposed as the principal operating variables, and their effects on organic oxidation, nitrification and denitrification have been discussed on the basis of the experimental resultsusing a laboratory scale reactor. 98% of BOD and 80% of nitrogen were removed from an artificial night soil under the optimum DO and pH conditions. This process requires accurate controls of pH and DO. However, pH and DO can be readily controlled with pH and DO controllers. This method may be useful in biological waste water treatment because of the capital and running cost savings.
