Upgrades and improvements to the Marana Water Reclamation Facility made during the past year have resulted in a more efficient collection and treatment system, according to the town of Marana’s utilities director.
John Kmiec said that the improvements were designed to make the facility more durable, remove solid materials before they can enter the plant’s treatment lagoon, and enhance the biological treatment of the wastewater.
“We added a stainless steel-framed curtain wall between the treatment lagoon and the clarifier,” Kmiec said. “Biological activity takes place in the lagoon and then the wastewater moves into the clarifier to settle out any other particles before final treatment and disinfecting.”
The second upgrade the utilities department made, Kmiec noted, was “improving the solids removal station in the headworks area, which takes out plastic bags and other materials for disposal and cleans the water more effectively than before.”
He added, “This is a large metal filter on a conveyor belt that allows solids to stick to it and liquids to pass through, then bags the solids for later disposal.”
The third major upgrade to the facility was the addition of an air blower and new diffusers to the plant’s treatment lagoon which use oxygen to help along the biological process. With the new equipment, Kmiec said, “Microbes have enough oxygen to convert waste into a clean product and release nitrogen gas. A wave oxidation process then takes the nitrogen out of the water, which more efficiently puts air into the treatment lagoon.”
The total cost of all three upgrades was under $700,000, Kmiec said.
Marana assumed management of the wastewater system in the northern part of the town in January of 2012, Kmiec said, acquiring the plant and its collection lines from Pima County in April of 2013 after a series of lawsuits and appeals. The town paid Pima County $18 million for the facility northwest of Luckett and Marana roads.
“As part of our agreement with Pima County, we identified the Saguaro Bloom development in north Marana as part of the sewer system that could be turned over to us as soon as we had the pipeline to take the effluent,” Kmiec pointed out. “We already provide the water in the area and want to own the effluent too and get the effluent credits, especially for such a large development that will consume a lot of water in the future after it builds out.”
Marana plans on extending its sewer line along Tangerine Farms Road where there currently isn’t any infrastructure, west of the village of the Rillito, under the Santa Cruz River and tie it into the Saguaro Bloom lift station.
“Once that connection is made, it will become part of the Marana system and Pima County won’t have to operate that lift station any more,” Kmiec observed. “It relieves Pima County of lift stations at Saguaro Bloom and another at the north end of Continental Ranch, which then sends the effluent to the county’s Ina Road plant.”
Kmiec estimated the design and construction of the extended sewer line will cost $6 million. He said the town is in the predesign part of the project now, acquiring easements for the line, and hopes to get into the design phase in the next couple of months. Kmiec said the target for finishing construction is the Spring of 2016.
Kmiec noted the benefit to the town of extending the sewer line is twofold.
“We get the effluent and the effluent credits, and the line adds critical infrastructure at Tangerine Farms Road and Interstate 10, which could help expedite any large commercial development for that corridor,” he said.
Another project at the Marana Water Reclamation Facility that’s recently gone into the design stage is a recharge facility planned next to the wastewater plant.
“Right now, the high quality water from the plant is being discharged into a wash, which doesn’t give us any recharge credit,” Kmiec pointed out. “We want to put in a recharge facility that will get the town credits from the Arizona Department of Water Resources.”
The way the town will manage that is to build a couple of basins on a 49-acre property east of the wastewater plant.
“We plan to add a small park and riparian area like at Sweetwater Wetlands,” Kmiec said.
Sweetwater Wetlands is a city of Tucson water treatment facility along the Santa Cruz River that recreates a riparian zone supporting a variety of wildlife while naturally treating and filtering water backwashed from filters at Tucson Water’s Reclaimed Water Treatment Plant.