An Envirogen Dual MinX regenerable ion exchange system for nitrate groundwater treatment

City of Modesto (CA) has awarded Envirogen Technologies, Inc. a $1.51M contract to reduce nitrate levels in extracted groundwater from two of its potable water production wells (Grayson Wells 274 and 295), using the company’s Dual MinX regenerable ion exchange technology.

Nitrate levels in the groundwater from these wells exceeds the maximum contaminant level (MCL) for drinking water – 45 mg/L nitrate or 10mg/L nitrate-N, and this treatment solution will bring the groundwater to less than 80% of the state’s MCL for city residents.

Envirogen was contracted for this project based on its nitrate treatment experience and service record for similar regenerable ion exchange systems.

Dr. Todd Webster, Vice President, Envirogen Technologies, comments, “We worked collaboratively with the City of Modesto as it explored ways to replace aging infrastructure and meet its treatment needs.


“Ultimately, Envirogen’s updated Dual MinX regenerable ion exchange system provides the best advanced solution, with effective nitrate treatment, low waste rates and minimization of salt usage.

“A key advantage of the Dual MinX is that it provides the same level of treatment as the city’s existing ion exchange (IX) unit, but its PLC-based control (programmable logic controller) and monitoring system also provides improved support for integration and monitoring.”

Maintaining water quality – always

The Dual MinX treatment system allows for continuous on-demand treatment with the use of regenerable ion exchange resins. The automated system controls the flow of water for treatment, as well as regeneration and rinse cycles for exhausted bed vessels, to maintain a set number of beds for treatment of the target contaminant of nitrates.

The PLC monitors all key performance criteria, including nitrate levels, and provides all system notifications and alarms. If a process issue or equipment failure occurs, the PLC triggers an alarm, which can trigger well shutdown, ensuring that water quality is always maintained. The PLC can also be remotely monitored and can be tied into the City of Modesto’s supervisory control and data acquisition (SCADA) system if necessary.

Says Mr. Jeff Daniels, Water Operations Superintendent for the City of Modesto, “The City has been collaborating with Envirogen for many years, and it has been a great business and technology partner. Based on that long experience with the company, I can emphasize that its regenerable IX water treatment technology is field proven and reliable.

“Also, Envirogen has been very responsive to system operation and maintenance for the City, helping to provide a stable water supply to the community.”

Work began in the summer, 2023, for the project involving the design, fabrication, delivery, installation, and start-up of the equipment in Summer, 2024.

Envirogen is a leading international provider of water and wastewater treatment solutions. The company solves complex challenges relating to water availability and quality, and helps its customers to increase productivity, reduce costs and meet environmental and sustainability targets.

Envirogen provides these solutions on a fully warrantied performance basis, along with operating services that guarantee long-term reliability and anticipated costs associated with the chosen technology.

This is achieved through offering:

  • Best in class water and wastewater treatment and process treatment technology
  • Expertise in design, project management and engineering
  • World class manufacturing and servicing capability