The major retrofit upgrades to the Ralston Water Treatment Plant filtration system and treatment lagoons will ensure access to safe drinking water for Arvada, Colorado residents. 

Construction is centered around updating the plant’s media filters, including rehabilitating the underdrain system and installing new media in the filters, which  remove suspended solids and debris in raw water, including clay, organic matter and algae. The project scope also includes upgrading the solids handling system, which includes two new solids pumps, the associated piping and updating the solids handling ponds.

While retrofit projects are common with water treatment facilities, this project has been more complicated than most due to the age of the original plant and the impact of other expansion projects completed over the years. These expansion projects resulted in each filter set being different from one another, requiring a tailored approach to the retrofit. As with all retrofits, unforeseen issues have arisen with each filter installation, requiring quick and innovative problem-solving by the project team.

Another challenge the team faced occurred before construction commenced when deteriorating concrete was identified in critical infrastructure areas, resulting in a leak in a critical portion of the plant. Despite still being in the preconstruction phase and not yet mobilized on site, PCL jumped in to address this issue during the peak of summer when the plant could not afford prolonged downtime. By implementing an expedited repair plan, the team completed the necessary repairs within 24 hours and limiting interruptions to the water service for the City of Arvada.  

Collaboration has been a key theme throughout this project, particularly in terms of the solids handling system. By leveraging lidar technology, which uses laser beams to measure precise distances and measurement, PCL scanned existing spaces and provided the data to the engineering partners. This allowed for the creation of a 3D project model, ensuring precise and efficient design, and an easier transition into construction.

Both the Ralston Water Treatment Plant and the Arvada Water Treatment Plant have remained operational throughout construction, requiring continuous communication with project partners and onsite staff at the plant. The team fostered a collaborative environment by using simple methods, such as placing a whiteboard outside the control room for daily activity updates and staff feedback. This approach helps ensure smooth operations alongside construction activities.

The completion of this project will bring substantial operational benefits to the City of Arvada. The upgraded filters produce more potable water during each filter run and have reduced the need for backwashing, which is when water is pumped back through the filters to remove accumulated  debris, from every 30 hours to about once a week. This will significantly enhance efficiency and increase overall treatment capacity. Additionally, the new solids handling system provides operators with increased ability to dry and manage solids produced from water treatment.

The project’s successful completion is crucial for the City’s ability to provide clean water to its residents, meeting regulatory requirements and future demands.