Sewage plants brace for ammonia rules

Standards intended to save fish from toxin

Todd Hartman, Rocky Mountain News

Published March 12, 2007 at midnight

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Sewage plants in metro Denver and across Colorado are preparing to spend hundreds of millions of dollars to comply with tough new rules to protect fish by limiting ammonia in rivers and streams.

The Metro Wastewater Reclamation District, the largest sewage facility in the region, plans $235 million worth of upgrades to its sprawling operation in northeast Denver. Other plants, including Boulder's and the Littleton/Englewood site - the state's third-largest - also plan major improvements.

The costly upgrades are linked to new federal ammonia rules, which are based on numerous studies showing that standards dating to 1987 don't sufficiently protect fish from what can be the toxic effects of the chemical - formed from urine and manure that wind up in wastewater plants.

Utilities will need several years to upgrade their facilities, but the effort could mean improved fish habitat in warm-water rivers such as the South Platte. Native species such as fathead minnows and johnny darters have been making a comeback there, but some, like the Iowa darter and plains minnow, still struggle.

"It's going to be a different river," Barbara Biggs, a government liaison with the Metro district, said of the South Platte. "It'll be kind of interesting to watch and see what happens over time."

Ammonia isn't always fatal to fish, "but it certainly counts as a stressor," said Pete Walker, a fish pathologist with the Colorado Division of Wildlife. It crimps their ability to cope with other environmental hardships, including disease, he said.

Colorado's nine-member Water Quality Control Commission is expected to adopt the new ammonia standards for each major river basin at a hearing Tuesday, but - at the same time - will likely give wastewater plants several years to comply.

"Their upgrades are costing many millions of dollars . . . so the commission has stated they want to implement these (rules) in a way that's realistic for communities to have time to take steps" to comply, said Paul Frohardt, commission administrator.

The upgrades will likely mean higher wastewater bills for customers, though it varies from place to place.

For Metro's 1.5 million customers in the Denver area, wastewater bills are expected to rise roughly 7 percent annually for the next "several years," Biggs said, to help cover the costs of the massive project.

The ammonia-related upgrades at Metro, one of the largest wastewater plants in the Rocky Mountain West, require expanding the north side of Metro's plant and completely rebuilding the southern side of its facility.

Wastewater makeover

• Who's affected: Sewage treatment plants across Colorado.

• What's the cost: Hundreds of millions of dollars, including roughly $24 million at the Littleton/Englewood plant and $30 million at Boulder's facility.

• Why: To comply with new regulations to tighten limits on ammonia in rivers and streams to protect fish.

• What's ammonia: A chemical associated with urine and feces. It collects at wastewater plants and can be harmful to fish even after the water is treated and released into streams.

hartmant@RockyMountainNews.com or 303-954-5048

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