K.G. Walters Concrete Project Manager Josh Backman talks about the construction process of the new bioreactor at the wastewater treatment plant on 5th St. in Carson City Thursday.
Six months in, construction at Carson City’s waste water treatment plant is on time and on budget.
If the $30 million, 18-month project stays on track, there could be $2 million left over to do some additional work there, said David Bruketta, Carson City utility manager.
That could include needed fixes to the pumps at the headworks where the sewage enters the Water Resource Recovery Facility.
K.G. Walters Construction and Q&D Construction Inc. broke ground in March weeks after the Board of Supervisors gave its OK to the project contract.
The biggest piece of construction is the addition of two, huge concrete tanks called bioreactors that replace the current secondary system at the plant.
The side-by-side tanks remove nutrients that make the water suitable for reuse.
The 20-foot tall tanks will comprise 5,000 cubic yards of concrete and should help reduce odors that emanate from the plant when the aerated ponds that make up the current secondary system are shelved.
“(The bioreactors) are not state of the art but they are tried and true technology,” said Bruketta.
At the same time, a fourth clarifier or settling tank, another piece in the secondary system, is under construction.
That requires 460 cubic yards of concrete and should be completed in November.
The entire 1A phase of the project requires 8,000 cubic yards of concrete and 4,500 cubic yards have been poured so far, said Jim Morris, project manager for the city. Two new generators are being added to power separate halves of the facility.
“That gets us off the archaic, ancient electrical equipment we had that we couldn’t even get parts for,” said Bruketta.
The 5th Street facility produces water for reuse.
Most of the year, the effluent is pumped to the Nevada State Prison Farm and several local golf courses.
In the winter, when it’s not needed for irrigation, the reclaimed water is pumped to Brunswick Canyon where it’s stored.
The facility staff gets routine reminders why the project at the more than 50 year-old plant is sorely needed.
The plant lost power when thousands of NV Energy customers lost electricity two weeks ago.
The emergency generator was turned on and tanks were filled with incoming sewage.
“But two to three more hours without power and we would have had to put it in ponds,” an open air area on the east side of the facility property, said Bruketta.
A week or so before the power outage, one of the sludge heaters blew, the second one in three years.
The equipment heats up solids to help break them down and uses methane gas produced in the process, which is both combustible and corrosive.
The construction project includes the replacement of the digesters, which include the heaters, for newer mixing technology.
That was planned later in the project but has been expedited.
Phase 1A is slated to be completed a year from now.
In the interim, phase 2B will be designed. That phase involves work on the headworks, which should further help reduce odors at the plant.
Both phases, Bruketta points out, are already covered by the five-year water rate hikes, which are now in their fourth year.