The 3Kings Water Treatment Plant along Three Kings Drive is nearly complete after construction began in 2019.
The plant processes 5,000 gallons of water per minute from the Judge and Spiro tunnels. That water is contaminated with natural remnants of Park City’s mining past, including arsenic and lead.
Park City Water Quality and Treatment Manager Michelle De Haan said it’s a unique position to be in.
“Throughout the country, Alta and Snowbird are some of the only other systems that are removing these kind of metals,” De Haan said. “We have more than they do in our tunnels, and part of it is because of the fact that the stream standards are actually more stringent than the drinking water standards.”
The water is treated in several steps.
“The first chemical we add is a coagulant… it’s an iron coagulant that essentially tries to have any particle that can be settled attached to it, and it ultimately can become settleable and filterable. We also add sodium hypochlorite, which is chlorine, at the front of the plant to oxidize metals from a dissolved state to a particulate state, again so that it can be settled or filtered.”
Sodium hydroxide is added to increase the pH, which allows zinc and cadmium to be removed. UV light is also used for any remaining pathogens.
The 2-acre plant discharges water into the municipal golf course ponds now and will start serving Park City homes this summer.
Public confidence in Park City’s drinking water has dramatically increased in the past decade. In 2022, 75% of residents surveyed ranked the city’s water as “excellent or good,” compared to 43% in 2011.
