The City of Kingman will pay cash for the $496,494 expansion to the Hilltop Wastewater Treatment Plant said Public Works Superintendent Jack Kramer.
"It will be paid from the expansion account that has been collected with the sewer bill," Kramer said.
"We knew when the facility was built in 1992-93 that we would be adding the third set of trains and evaporation basins."
The Hilltop facility, located north of Kingman past the airport near the Mohave Wash, was designed for three sets of "trains" to clean the wastewater.
Two were built in the original design to handle two million gallons per day.
The third will increase capacity another million gallons per day.
A "train" is a water channel planted with bulrushes and other plants that produce a litter where microorganisms live and remove nitrates from the wastewater.
Each train covers 25 acres.
The Kingman facility reportedly is the only one in Arizona that uses the biological method of both treating wastewater and removing nitrates.
Tested water coming out the end of the trains and evaporation basins is treated as potable as required by federal and state regulations.
Kingman City Financial Administrator Coral Loyd said most of water users within the city limits are on the sewer system.
"We have 5,544 customers on the wastewater system," Loyd said.
"All but 307 of them live within the city."
Kingman has 14,270 water customers with 7,739 within and 6,531 outside the city.
The 5,237 customers on sewer are two-thirds of the 7,739 water customers in the city limits.
This is the measure the city uses to estimate the percent of city homes and commercial buildings on the wastewater system,
City Engineer Pete Johnson said the bid will be certified and Pierson Construction of Tempe notified within 10 days.
He expects construction to begin after Jan.
Wastewater superintendent Jim Corwin and his staff have a nursery of the bulrushes and other plants needed for the trains growing at the site.
When construction is completed in the spring, Corwin will transfer the needed vegetation to the newly constructed train.
"We expect the new train and evaporation basins to be operational during the summer months," he said.
Currently, 1.2 to 1.5 million gallons of wastewater per day flows into the Hilltop facility for treatment.
Corwin said that two thirds of that evaporates or transpires through the plants during summer months with only a third reaching the runoff at the end of the trains.
"During the winter, the plants are dormant and the evaporation is low and about as much water runs out after treatment as comes in," he said.
He said each train is designed to handle one million gallons of wastewater per day but the system works more efficiently at 750,000 gallons per day.
The current two trains are at about maximum use for best treatment.
City Manager Lou Sorensen said Kingman purchased two sections (1240 acres) of land where the Hilltop facility is located giving the city ample room for expansion as the city grows.