Supervisory Control and Data Acquisition (SCADA) system has become one of the most important elements in the operation of the wastewater treatment system at Cumming, Ga., according to Randy Payne, environmental manager. “It has revolutionized the bio-phosphorous and denitrification processes and has created a paradigm shift from a manual operations mode to a verification mode,” said Payne.

Tyson Cumming SCADA system benefits and functions:

• Monitors and controls pumps/flows from EQ basin using ultrasonic level detection.
• Initializes and stops chemical feeds and DAF operation based on flow.
• ORP control and monitoring of anaerobic process through control of the blowers.
• Dissolved oxygen control and monitoring for aerobic and anoxic zones by blower and bleed-off valve control.
• Monitors and controls flow rate from the aerobic zone to the anoxic zone.
• Monitors operation of the belt press.
• Monitors and log hours of operation of all pump and blower motors.
• Control chlorination/dechlorination of effluent.
• Three-tier alarm system
• Daily process control data entry system that calculates food to mass ratios, sludge volume index, mean cell residence time, total pounds of solids in each reactor, as well as a monthly average of all entered values.
• Accessible by remote location for real-time control and viewing.

Bio-phosphorus removal that takes place during treatment has allowed Tyson to reduce alum usage by 50 percent and produce treated effluent with a phosphorous concentration of 0.5 milligrams per liter or less. Bio-phosphorous removal saves money on both alum purchases and on sludge disposal.

Tyson has implemented several other innovative practices in its wastewater treatment system at Cumming. Sodium bisulfate is used to dechlorinate the incoming wastewater. This is done so that chlorine used as a disinfectant at the processing plant won’t create chronic or acute toxicity problems for the nitrifying bacteria. The Cumming wastewater treatment team developed a two stage pumping system that doses DAF effluent with a 40 percent sodium bisulfite solution.

Operating a wastewater treatment system in town has its challenges, and odor is one of them, particularly when you are located three quarters of a mile from the courthouse. A geodesic dome covers the anaerobic tank and is used to capture and evacuate malodorous air from the headspace of this tank and pump it into the aerobic tank. Doing this controls odors and uses the power it takes to move air off the anaerobic tank to aerate the aerobic tank, and this shaved $75,000 off the annual electric bill.

Even sludge handling has received some innovative improvements at Cumming. Returned activated sludge (RAS) is removed from the floor of the clarifier, and these biosolids are pumped to the belt press where they are conditioned with polymers and dewatered. The solids percentage of the dewatered sludge is 17 to 18 percent, up from around 4 percent when it is removed from the clarifier. Biosolids are disposed of in a landfill at a cost of $30 per ton, so the sludge press has provided a significant savings.

Water conservation and reuse programs have been successful at the Cumming processing plant. Over 300,000 gallons of water are reused each day inside the processing plant. Daily purchases of potable water from the city have been reduced from 1.75 mgd to 1.2 mgd.