The new centralized treatment plant primarily consists of two multi-cell horizontal pressure filters in combination with Hydrous Manganese Oxide (HMO), and sodium hypochlorite chemical storage and feed systems. These systems work together to remove iron, manganese, and radium from the water supply.

The two 8-inch water mains from Wells No. 6 & 7 and Wells No. 8 & 9 combine within the treatment plant upstream of the pressure filters. Sodium hypochlorite and HMO can be fed to each incoming water main prior to filtration.

Each pressure filter consists of three cells filled with specialized granular media that removes iron, manganese, and radium. Filtered water then exits the filters and is stored in the 1-million-gallon storage reservoir. Prior to entering the reservoir, sodium hypochlorite, polyphosphate, and fluoride are added to ensure water quality and stability throughout the distribution system.

The completion of these upgrades marks a significant investment in the City of Marengo’s future and represents a major step forward for the community. With enhanced water quality, increased redundancy, and added capacity for future growth, the new treatment facilities help deliver a safe and dependable water supply for residents and businesses alike.

Water System Project History

During the initial step in this comprehensive and time-sensitive effort, the City partnered with its engineer, McMahon Associates, Inc., to complete a Comprehensive Evaluation aimed at identifying the most cost-effective and efficient solutions to enhance water system service reliability and water quality for the community.

As a part of evaluation, McMahon evaluated water supply, storage and treatment system needs and improvement alternatives. In 2024, the City began construction on the recommended improvements, which included the construction of a new well (Well No. 9), water transmission main improvements and a new centralized water treatment plant.