Results of a demonstration of the feasibility and benefits of applying several advanced wastewater treatment control strategies in an operational treatment plant using a digital computer are presented in this report. The work was conducted in a full size (35 MGD capacity) secondary treatment plant at Palo Alto, California. Control strategies tested were for the secondary treatment portion of the process and involved regulation of aeration tank dissolved oxygen (DO) and food for microorganism ratio (F/M). Two variations of F/M ratio control were evaluated using respectively air flow and a direct measurement of sludge respiration with an on-line respirometer to estimate food (BOD). An extensive data collection program was incorporated which allowed detailed statistical evaluation of each control algorithm with regard to performance, effluent quality impact, operating costs, and reliability, comparison was made to similar data collected during benchmark manual operation tests. Overall results indicate digital control using advanced control concepts is feasible and that demonstrable improvements in effluent quality are obtained. Direct operating cost savings in the form of an 11% reduction in air use was also shown for DO control.

Report prepared by Systems Control, Inc., Palo Alto, California. "Program element no. 1BB043." Includes bibliographical references (pages 89-90).