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Evoqua Selected to Replace Screw Pumps for the City of Modesto, Calif.

Improving Performance and Extending Operational Life

The Sutter Primary Wastewater Treatment Facility, built in 1919, treats an average of 20 million gallons per day (MGD) for the City of Modesto.  The treated effluent is discharged to a secondary site, where it is then treated for agricultural reuse. 


Currently, four screw pumps have been operating at the facility for over 20 years to draw wastewater into the plant's screens and grit chamber for initial treatment. During the life of this installation, Evoqua's DAVCO™ field service team provided rehabilitation and aftermarket parts to help extend the system's operational life. 


The City of Modesto recently received budget approval to replace two of the  pumps and selected Evoqua's Internalift® screw pump technology. The new pumps have been designed to be 96 inches in diameter and 38.3 feet long, each with the capability of lifting 18,750 gallons per minute (GPM) of raw wastewater. In addition, the City of Modesto's maintenance team worked with Evoqua's engineers to develop a custom upper bearing seal for the pumps to improve operational efficiency and meet treatment application requirements.

Evoqua's Internalfit® screw pumps are an excellent solution for lifting water, wastewater, and other liquids in a variety of municipal and industrial applications. They provide pump efficiencies as high as 85% and volumetric efficiency of virtually 100%.  

modesto-casestudy-1104x648.jpgThe Internalift® Screw Pumps installed at the Surrey Primary Treatment Plant are designed to be 96 inches in diameter and 38.3 feet long, each with the capability of lifting 18,750 gallons per minute (GPM) of raw wastewater. 

" The existing screw pumps had been in operation for over 20 years," stated Monte Hamilton, Plant Maintenance Superintendent for the Treatment Plants. "Evoqua's DAVCO product line had been providing rehabilitation and aftermarket parts through the years, extending operational life, and we are excited to be able to secure a budget for the purchase of new pumps to improve treatment efficiency and performance. "


Evoqua's DAVCO™ field construction and service team will provide a full turnkey project solution that includes installation and field service. Commissioning of the new screw pumps is scheduled for mid-2022 in time for the City of Modesto's annual rainy season. The replacement of the remaining two screw pumps is planned for the future.

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