Generic Feed Forward Control of Activated Sludge

Feed forward controllers for the completely mixed activated sludge process were developed and tested against the sludge growth rate models of five authors by computer simulation. Control was effective for all models and was shown to apply generally to growth models wherein specific growth rate is any function of substrate concentration. The control strategy involved manipulation of the recycle rate of return sludge. When the recycle rate was under proportional control from measurement of influent flow rate and derivative control from measurement of influent substrate concentration, soluble substrate in the effluent was minimized and stabilized. With recycled sludge storage, control was more effective.