Moline Water Plant Upgrade

Faced with increasing difficulty in operating and maintaining its aging water treatment facilities, the City of Moline was in need of near‐term plant improvements to continue to meet treatment requirements.  

Phase I included enhancing the reliability of the existing 12 MGD plant capacity, allowing continued compliance with increasingly restrictive turbidity regulations and goals. The rehabilitations and replacements included comprehensive revamping of the plant’s electrical system, upgrading of chemical storage and feed facilities, placement of new filter media in all eight plant filters, new sodium hypochlorite feed facilities, improvements to existing heating and ventilation systems, dehumidification of the filter pipe gallery, new roofs, and repairing concrete basins and building structures. Challenges on the project included meeting treatment, space, community, and environmental concerns. The Phase I improvements were completed while maintaining the plant without interruption of operation throughout construction.

The upgrade saved an estimated $10 million over construction of a new plant at a different location and will continue to serve Moline’s drinking water needs for the next 40 years. Innovative multifunctional reuse of existing basins that might otherwise have been abandoned, included repiping these basins to allow parallel or series operation and use before and after new ClariConeTM treatment units installed to improve softening and clarification. With this flexibility, plant staff can choose supplemental treatment to more effectively control the clarity, softness, taste, and odor of the treated Mississippi River water supply, depending on raw water characteristics. 

In addition to meeting the city’s goals to improve plant reliability, economy, and efficiency, this project has met the aesthetic requirements of the city’s Renew Moline redevelopment program.  The project team then designed Phase II ultraviolet disinfection facilities for the Moline plant for compliance with requirements of the Long Term 2 Enhanced Surface Water Treatment Rule. Ultraviolet reactors were placed on the discharge of individual filters or on the combined filter effluent. Filter effluent piping modifications were also implemented to provide additional filtration capacity. 

Project Highlights: 

• Ultraviolet disinfection of Mississippi river surface water treatment plant 

• Regulatory compliance and flexibility for future growth and meeting evolving regulations 

• Savings of $10M over construction of a new plant 

• High lift pumping station rehabilitation 

• Filter upgrades