LOGAN — It is one of the biggest systems — if not the biggest of its kind in the United States — and it has served Cache County area residents well for nearly 50 years.
Unfortunately, the sprawling lagoons that cover 460 acres on Logan's west side have outlived pollution standards that have been instituted since the system was first installed.
High concentrations of phosphorus contained in the wastewater, even after treatment in the system, flow in irrigation water across farmlands and wetlands and are eventually dispersed at Cutler Reservoir, just a few miles away.
The freshwater lake that impounds the Bear River is suffering from too much phosphorus, landing it on the state's impaired waterways list. Excess concentrations of the nutrient lead to low-dissolved oxygen levels which manifest in the night in the absence of the sun.
Such pollution threatens aquatic life and the entire food chain at the small reservoir and the adjacent watershed. That problem, compounded by the system's excess ammonia levels, is necessitating an expensive fix for Logan — as much as $125 million — to meet state and federal water quality standards.
City officials recently decided to move ahead with plans for a new, mechanical treatment plant that will occupy about 100 acres south of the existing lagoon system. The funding will come from a variety of sources, such as the city itself, the U.S. Department of Agriculture and a $50 million loan from the state. Households can an expect an estimated jump of $10 to $13 per month on the sewer bill once the system is in place.
The new plant is a signficant financial step for the city — its entire annual budget hovers just under $133 million. But the city is embarking on the next steps, said Issa Hamud, Logan's environmental director.
"The next stage is the logistics, managing the design and construction, making sure it is completed in time and it runs efficiently," he said. "It is a huge project, a $125 million project that is not going to be easy."
Hamud said the lagoons, since their installation in 1965, have never suffered an operational problem. It is nutrient pollution that is necessitating the change.
Logan has been given a deadline of 2017 to reduce the amount of phosphorus in its discharge water by more 60 percent and also has to shave the amount of ammonia in its wastewater. Ammonia is a toxic derivative of nitrogen, but a natural part of waste that has to be removed from wastewater to a certain federal and state standard.
"Some wastewater treatment plants are effective at removing it, others less so," said Walt Baker, director of the Utah Division of Water Quality.
When the federal limit on ammonia changed more than a decade ago, the city put in 260 acres of wetlands to act as a sponge for the ammonia.
"We built those additional wetlands to further polish the water coming out of the lagoons," Hamud said.
The standard became more stringent again in 2008, and by 2011, Baker said, the amount of nutrients showing up in testing demonstrated that the lagoon system was struggling.
"The lagoons themselves don't help with the treatment of ammonia and the wetlands don't either, so you have a double whammy," Baker said.
The lagoons may have functioned well for Logan early on, but Baker said growth and an extension of the system to serve outlying communities such as Providence, Nibley, Smithfield and Hyde Park are posing additional challenges.
"There is a reason why no community along the Wasatch Front has lagoons anymore," Baker said. "The land cost would be astronomical and the level of treatment that needs to be effected just can't be achieved by a lagoon."
Baker said the holdout system in this era is unique and notable for its size.
"I don't know if there are any larger ones in the United States; Georgia may have some," he said, "but west of the Mississippi, I am aware of no lagoon that is bigger than this one."
Hamud said he is hopeful that at least some portion of the lagoons can be saved to continue the city's partnership with Utah State University in a biofuels project. Algae grown in the lagoons help with the uptake of phosphorus and then are harvested and turned into biofuel. The lagoons were transformed into algae and fertilizer farms— a first of its kind project — with stimulus funding awarded in 2009.
"It could be beneficial to communities to continue to work on the algae project with USU," Hamud said.
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