#20-006280 - Construction Manager at Risk-Water Treatment Plant Improvements Project

The City owns and operates the RO WTP and Greensand WTP, which are currently rated at 6.6 and 4.5 million gallons per day (MGD), respectively. The City also has an agreement with the City of Thornton to purchase up to 2.2 MGD. In total, these three finished water sources combine to allow the City to provide up to 13.3 MGD of finished water to customers. With a current summertime maximum daily demand of 11.4 MGD, the City has a surplus of up to 1.9 MGD. However, if the September 2022 compliance date for RO brine nitrate discharge is not met, the RO WTP must be taken offline. In addition there is a brine discharge compliance date of June 2023 for sulfate and selenium. This will immediately drop capacity to 6.7 MGD which is insufficient to meet drinking water demand. As part of this project, City intends to expand the capacity of the Greensand WTP from 4.5 mgd to 12 mgd.
The City has engaged Brown and Caldwell (Engineer) to perform preliminary design and detailed design to determine the treatment processes and design criteria to be used in the design of the project. The pilot testing is currently 30% complete with final design starting in third quarter of 2020.