Thanks to an innovative tertiary treatment package, the city of Galesburg, IL, has been providing residents with a green and economical solution to their wastewater needs since 2010.
In 2008, the city was seeking an economical way to improve their wastewater treatment needs and reduce Total Suspended Solids (TSS) concentrations, especially during high flow conditions when solids could wash out from the processes. To achieve this goal, the city council approved funding for a new wastewater treatment plant, and Xylem Inc. was contracted as part of the "solutions" team.
The Galesburg plant has an average design flow of 11 mgd and peak design flow of 28 mgd. To meet the needs of the plant, Xylem installed an innovative system for the facility. The system uses a Sanitaire DrumFilter and Flygt controls for the submersible lift station pumps. A Bell & Gossett Triplex 70VS Variable Speed Booster Pump system operated by a Technologic® 500 Pump Controller and variable frequency drives (VFDs) is included to boost water pressure.
During normal filtration, no energy is consumed by the system. Effluent from the final clarifiers is polished by the DrumFilters with a 17-micron filtering screen. The lift station pumps on and off in sequence to match effluent flow feeding the system.
Only when a backwash cycle is initiated does the DrumFilter system use energy. The filtering process is not interrupted during the backwash cycle, which is when the 70VS system starts the lead pump by detecting a drop in the backwash line pressure.
The system has the ability to sequence additional pumps as required to meet demand and maintain the design pressure required to spray away the solids. The system was designed so that the third pump in the sequence was designated as a standby unit. The Technologic's automatic alternation of the lead pump balances the wear on each pump. In addition the 70VS provides remote run and alarm status indication to the Flygt monitoring and control system to ensure total system integration of the Xylem products.
The 70VS system with Technologic controls integrates seamlessly with the DrumFilter to provide an energy-saving tertiary filtration solution.
Thanks in part to this solution from Xylem, the city is now reporting effluent concentrations of less than 5mg/L.
Benefits of the 70VS system include:
- Energy-savings by most efficiently meeting system demand
- Avoidance of motor damaging and energy wasting in-rush currents with the soft start capability of the VFDs
- Precise pressure control with a single system set point
- Reliable Bell & Gossett pump protection algorithms
Xylem's Applied Water Systems (AWS) includes the company's global brands that work together to meet the needs of growing populations, communities and industries. The range of energy-efficient pumps, boosters, drives, valves, controllers and water systems support numerous applications in building services, general industrial, food and beverage, marine and agricultural markets around the world. For more information on AWS and its brands visit www.xylemappliedwater.com.