Improvement of ammonia removal in activated sludge process with feedforward-feedback aeration controllers

Abstract

In the paper three linear aeration controllers that can be easily implemented are presented and evaluated on the activated sludge process pilot plant. Controllers differ according to the information that is used about the process, which can be oxygen in the last aerobic reactor, ammonia in the last aerobic reactor and ammonia in the influent. The aeration controllers that are addressed are: oxygen cascade Pl controller, ammonia cascade Pl controller and ammonia feedforward-cascade Pl controller. Experiments show that, in comparison with the oxygen cascade Pl controller, the ammonia cascade Pl controller allows better control of effluent ammonia and airflow savings of around 23%, while the ammonia feedforward-cascade Pl controller gives the best reduction of ammonia peaks and can save up to 45% of the airflow. © IWA Publishing 2006.