KINGMAN - It'll be a few months until the Downtown Wastewater Treatment Facility is completely done, but it's been operational since August as designers and inspectors work out the kinks.
Built on the same site as the old one, the new plant is a complete upgrade capable of turning sewage into A+ effluent. Up to this point, it's cost $15.2 million to build. The original estimated cost was $18.5 million, but once completed it's expected to be more than $1 million cheaper than that. The need to build the plant came from the fact that the old one was not compliant with federal nitrogen removal requirements.
Other than the use of a few chemicals at different stages of the treatment process, the Downtown Wastewater Plant is "essentially all natural," said City Engineer Greg Henry.
From the plant's centerpiece, a high-tech filter known as a membrane biological reactor, to the use of ultraviolet light for disinfectant purposes, the plant's reliance on chemicals is basically nil.
"The use of UV is fairly sophisticated," Henry said. "And it's better than chlorine because of the harmful byproducts produced by the use of chlorine."
Once sewage goes through the treatment process and all the garbage, grit and sludge has been removed, what's left is A+ effluent, which is then discharged into the wash adjacent to the plant.
Construction continues on the wash, as designers are basically rerouting its path and making it so the plant sits above the 100-year flood plain while at the same time doing away with the old plant's lagoons.
Since how compliant a treatment plant is with federal requirements hinges on its ability to remove nitrogen, a quick look at the process is warranted.
Sewage comes in full of ammonia, said Assistant City Engineer Phil Allred. Microscopic bugs covert the ammonia to nitrate, which is then devoured by another set of microscopic bugs. Those bugs then convert the nitrates into nitrogen gas, which is then expelled from the system, he said.
The end product is A+ effluent, which could be used for industrial processes once the city finds a buyer or works out an agreement with an entity. But for the time being, the effluent will simply be discharged. The old plant produced a B- effluent, which didn't meet the B+ rating demanded by the federal government.
During treatment, sludge, solids, grit and garbage is separated from the water. The solids and the garbage go to landfills, and the sludge is trucked up to the Hilltop Wastewater Treatment Facility where it is composted and used as fertilizer in the city's parks and at the golf course, Henry explained.
Though Felix Construction of Coolidge was contracted to construct the plant, the city was able to use its staff to oversee much of the process and do many of the required inspections. This allows city staff to learn how to run the plant before it officially opens, which wasn't the case at Hilltop.
"City staff is really familiar with how the plant was built and how it works," Allred said. "It's a great side benefit."
Jack Plaunty, a public works inspector with the city, has been at the plant for every step of the process, and he's basically a walking treatment facility encyclopedia. He's on top of each intricate part of the facility from how each part works to when the plant is expected to be finished.
For instance, the original design called for the plant to be inside an enclosed building, but the decision was made to scrap that idea and allow the plant to be an open-air facility.
Vice Mayor Janet Watson said she was concerned with this fact. But Plaunty put her at ease when he explained that the equipment is rated for outside use and the cost of enclosing the plant would be substantial because everything within would need to be explosion-proof. An enclosed wastewater treatment facility creates a highly caustic and explosive environment, he said.
Everything must be sealed from explosive gases and made with stainless steal in an enclosed treatment facility, which costs a great deal more than how the plant is actually constructed, he said.
Also, unless you're right next to one of the treatment chambers, the facility's smell is hardly noticeable.
Henry said the decision to not enclose the facility saved the city roughly $1 million.
Once fully operational, the plant will be staffed with two people, who mainly work during the day, Henry said. The plant basically runs itself, so there's no need for a large staff. Of course, the two who will staff it will be on call during the night in case something goes wrong.
As the wash is rerouted and staff continues to wrap up testing, each day that passes brings the city closer to having its second, fully operational, federally compliant wastewater facility. But when that happens is still up in the air.
"We want to take as little time as possible to finish," Plaunty said. "Hopefully that's about two months."