Skeptics contend this process, which has yet to be commercially applied anywhere in the United States, would release harmful emissions despite the company's promises that it has proven to be a safe and clean way to produce energy from garbage.
Now city officials believe the company can't pull off its vision, given the weak market for recycled material and low tipping fees, as well as Navitus' prolonged silence and failure to commence construction within the two-year window specified in its contract.
"If they were to come back to the city and we had a meeting of the minds and a model that was financially viable, that's a talk we are interested in having," said city spokeswoman Nicole Martin. "The project hasn't moved forward at all, with us having no word from the company. We will continue to pursue other options. We don't want to continue burying our waste. We want to look for smarter ways of handling it."
Navitus' 20-year contract required it to pay the city $1,667 in monthly rent on the city-owned property, as well as cover most of the costs of maintaining the land and reimburse the city for site work already done by a previous contractor Sandy had hired to develop a waste-transfer station there.
The company has failed to meet at least some of these financial obligations and is out of compliance with the terms of its contract with Sandy.
"Having been previously notified verbally, Sandy City is now in the process of giving written notice of compliance issues, with a 15-day window to rectify the situation or we will be forced to formally terminate the contract," Martin wrote in a follow-up email.
Navitus CEO Heidi Thorn, who lives in Sandy, did not return a phone message.
The city had hoped to become the nation's first "zero-waste" city with Navitus, which said it would divert Sandy's municipal waste from landfills and turn it into something useful, all without polluting the environment. Residents wouldn't even need to put recyclables into separate bins.
The city touted the potential benefits in January 2015, when the DEQ scheduled hearings on the air-quality permit. Environmental advocacy group HEAL and other critics said such assertions were "too good to be true" and argued the project would threaten public health.
More than two years after Navitus' initial applications, the Utah Division of Air Quality (DAQ) had yet to issue a permit.
Thorn and her firm's lobbyist appeared before a legislative committee in May 2016 and gave an optimistic assessment of the project, pointing to the state permits as the holdup.
"It's a really innovative technology. They can deploy it around the country because it's so clean," lobbyist Jeff Hartley told the Public Utilities, Energy and Technology Interim Committee on May 18.
"The longer it takes, the harder it gets to keep your capital interested, especially when you are a first facility," Hartley said. "When we don't get permits, we can't operate. If we can't operate, we can't employ, we can't pay taxes."
The DAQ issued Navitus' "minor source" permit two months later, on July 15.
DAQ Director Bryce Bird explained that permits of the type Navitus sought typically take six months to process, but this one took much longer because the company was proposing a first-of-its-kind facility. Processing such an application takes additional time to apply federal emissions standards, especially given the diversity of wastes Navitus would use.
The company has a plant up and running in North Carolina in partnership with the U.S. Forest Service, Thorn said. That plant processes mostly woody biomass, a feedstock much different than the trash that would be processed in Sandy.
HEAL was pleased the project appears dead despite acquiring a permit.
"Many Sandy residents were rightfully skeptical that Navitus could miraculously turn trash into clean power," said Ashley Soltysiak, HEAL Utah's senior policy associate. "Our research showed that facilities like Navitus often produce troubling amounts of dangerous air pollutants, including dioxins. It never made sense to have Sandy residents be the guinea pigs subject to emissions from an untested technology."
Brian Maffly covers public lands for The Salt Lake Tribune. Maffly can be reached at firstname.lastname@example.org or 801-257-8713.