AUTOMATED INSTRUMENT MONITORING SYSTEM AT MILWAUKEE'S SOUTH SHORE WASTEWATER TREATMENT PLANT

ABSTRACT Six years of full-scale operation with a computer-controlled secondary activated sludge plant has shown consistent improvement of final effluent quality and operating costs have been cut. Design of the computer instrument package began in 1974 and construction was completed in 1977. A two-year service performance agreement was part of the contract. It was during this period that the majority of the control loops were developed and fine-tuned. The experiences encountered during initial startup through control loop generation and process control interface will be included. Instrument evaluation expectations were not realized due to inherent problems of fouling and/or excessive maintenance. Finally, the real bonuses were best identified in long-term effectiveness and economic value. Reduced manual intervention occurred simultaneously with increased awareness of the process activities. Operational loops smoothed out process variations, reduced energy and increased equipment life, and held effluent quality levels well below permit requirements.