By Naomi Hatch —
“In 2008, the Town of Taylor was required to build a wastewater treatment plant because the lagoon systems were overloaded and were at risk,” recounted Town Manager Eric Duthie.
“The plant was built through a small interest loan and is now capable of handling sewage treatment for years to come.”
With the new wastewater treatment plant came the problem of disposing of discharged effluent, which is treated water that can be used to grow crops for animal consumption.
An agreement was made with Bio Solids Inc., owned by Alma Saline, whose family has farmed in Taylor for many years.
“This is a green project,” said Duthie. “It is environmentally safe, economical and useful instead of sending water down a stream or sludge into a landfill.”
Saline explained the three steps of this environmentally safe method of disposing of biosolids through a natural recycle process. First is removal of biosolids from the treatment site; second is transporting the biosolids to the fields; and third is injection of biosolids 6” below the top of the soil.
“By putting biosolids back into the earth, we are encouraging and contributing in a natural closed loop cycle,” explained Saline on a DVD he recently has put together.
Saline noted that removal of biosolids from the wastewater treatment plant in Taylor begins by pumping the solids from the bottom of the collection tank into a 6,500-gallon transport, which takes approximately 12 to 15 minutes. They also pump biosolids from the lagoon directly into the transporter. Saline explained that the higher the percentage of solids, the more efficient the operation. When the transporter is full, it is driven to the field location and then the biosolids are pumped from the highway transporter into a 7,000-gallon injection tanker.
When the umbilical cord is released, the biosolids are ready for the injection phase, when the injection tanker incorporates the biosolids 6” into the topsoil. There is a safety process that ensures the shanks are in the soil before the release of fluid, which keeps flies and other insects from being attracted to the sludge. It takes seven minutes to inject 7,000 gallons into the soil.
There is little or no smell, since the ground absorbs the moisture within a few minutes, and then the biosolids decompose in the soil and contribute to fertilization of field crops, which supports a natural recycle process.
The process follows guidelines set by Arizona Department of Environmental Quality (ADEQ) regulations. ADEQ inspects all fields and approves them before the process can begin. “The benefits to biosolid removal include: no interference with daily operation of the treatment process; no expensive chemicals or polymers to add to the process; and no need for the town to purchase dewatering equipment, such as centrifuges and water presses,” said Saline.
He reported that this is a timely process, noting that 4,000 cubic yards of biosolids can be handled in four working days. He said that the injector tanker can move 30 loads per day. Saline has been approved to inject biosolid material on 300 acres of farmland, which would be approximately 600 loads of biosolid injected per year on a continuous basis.
Saline performed injection from the Taylor Wastewater Treatment Plant on Nov. 15 and Jan. 20.
Other communities transport the sludge to landfills.
“The town is seeking additional community partnerships to expand this safe and economical process,” said Duthie.
Saline reports that he has plenty of acreage to handle additional towns’ biosolids.