Every day, nearly 140 million gallons of wastewater is treated by the Denver Metropolitan Wastewater Reclamation District.
Gene Taylor is one of the operators who monitor the water, with the help of cameras and sensors at every step of the treatment process, as it makes its way from household sinks, drains and toilets into the South Platte River.
The main concern, Taylor said, is to ensure that chemicals and nutrients are at safe levels when the water leaves the system and enters the river.
But the appropriate level of nutrients and chemicals, including phosphorus, nitrogen and ammonia, is the subject of ongoing discussion for water-quality experts and legislators.
Wastewater standards nationwide are largely guided by the 1972 Clean Water Act, which sets wastewater and water-quality standards for all contaminants in surface waters. The Environmental Protection Agency (EPA) enforces these standards through the National Pollutant Discharge Elimination System permit program, which regulates point sources, including pipes and manmade ditches, that discharge pollutants into bodies of water.
The EPA typically delegates the issuing authority of these discharge permits to individual states. In Colorado, the state Department of Public Health and Environment’s Water Quality Control Commission is charged with issuing these renewable, five-year permits that carry mandatory water-quality regulations.
One of the most notable changes to the state’s water-quality regulations occurred in June 2005, when studies showed that high ammonia levels have a significant impact on the aquatic life near discharge areas. The regulations passed that year lowered the level of ammonia that treatment facilities are allowed to discharge.
The Denver Metropolitan Wastewater Reclamation District, which serves all but three cities in Jefferson County, is carrying out a $1.2 billion construction project to upgrade its treatment facilities to comply with discharge permit requirements.
Steve Frank, the Denver Metropolitan Wastewater Reclamation District’s public information officer, said $211 million of that amount is being spent to construct a secondary treatment area to filter out additional ammonia and nitrates from treated waters. He said the project is scheduled for completion by Jan. 1, 2015.
State water-quality officials are considering more changes to discharge regulations.
According to the EPA, too much nitrogen and phosphorus in the water causes algae to grow faster than ecosystems can handle it. The result is algal blooms that can significantly reduce or eliminate oxygen levels in water areas and result in fish kills.
To address the problem, the Colorado Water Quality Control Division proposed a water-quality-control regulation amendment in Dec. 2011 that would mandate large treatment plants to mitigate the discharge of these two elements into waters.
The Water Quality Control Commission gave preliminary approval to these regulations in March. It will review the amendment once more this month before sending it to the EPA for approval. If approved, the regulations would become effective June 30.
Nancy Keller, chairwoman of the Colorado Wastewater Utility Council, said the approval was a misstep because very few studies have been conducted to determine the effects of nitrogen on state waterways.
She said the regulations would force nearly 30 percent of the state’s wastewater treatment facilities to spend at least $2.5 billion each on added improvements and eventually cost the state nearly $25 billion over the next 10 years.
Frank said the funding for these construction projects would come directly from the cities served by the plants.
“It’s a shame to put billions of dollars into something that has errors in the science and limited grounds proving that it will eventually make a difference in the long run in the river,” Keller said. “If they applied it site-specifically in areas where there were problems, then there’s some very good potential that people would support it, but doing a blanket application across the state with no proof that we’re going to have any effect on our streams for billions of dollars is hard to sell to our city councils.“
Like many of the other 59 local governments served by the treatment plant, the city of Arvada passes wastewater treatment costs to homeowners and charges an additional fee to maintain the city’s 408-mile sewer system. Steve Wyant, Arvada’s wastewater superintendent, said the city is already addressing needs to replace miles of aging sewer infrastructure and expanding it to accommodate growth in the city’s northwest corner, including Candelas. He said the project cost is already estimated at almost $12 million.
Officials in Golden, which treats its wastewater through a contract with MillerCoors, also are concerned about the proposed changes.
“I think that everyone that has a plant has been scratching their heads and trying to get their arms around it,” Beierle said. “Utilities are fee-based, and there isn’t magic money to pay for improvements to plants if the standards or requirements change.”