Clean energy for clean water


While many residents don’t know what the Boulder Wastewater Treatment Facility is, the plant is taking steps to keep the community safe and energy-efficient.

The 75th Street center, which receives and treats all commercial and industrial waste from the city of Boulder, is equipped to handle up to 25 million gallons of wastewater daily. The actual amount is closer to 15 million gallons, which is treated through physical, microbiological and chemical methods.

“What we do is definitely a necessary step in keeping the community safe,” says Chris Douville, coordinator of wastewater treatment at the facility.

The water, once treated to Environmental Protection Agency and state of Colorado standards, is discharged into Boulder Creek. At that point, it’s not safe for consumption, but it is safe for recreation and contact with those downstream of the facility.

“What we’re doing is we’re taking what would happen in natural ecosystems and compressing it in time and space,” says Douville. “It takes a lot of power to do that, primarily electricity.”

But since 1986, the treatment facility has been finding ways to offset that electrical necessity. Back then, it was methane gas. Now, it’s solar power.

“For the last 25 years, we’ve been beneficially using the methane gas that we derive from treated solids. As we break down and treat solids, a gas is formed that’s primarily methane,” Douville says. “Methane has a combustion value, and we use a system called co-generation to make electricity.”

That system generates an average of 20 percent of the facility’s power needs, and it keeps methane from being released in the atmosphere.

“Not all communities do that. We’re on the exception end of things,” Douville says. “Normally what a facility would do is burn the gas, so they’d flare it, ignite it and combust it, and it would go off in the atmosphere as carbon dioxide and heat. Boulder made the commitment to produce electricity.”

While that program has been successful and beneficial, they haven’t stopped looking for new ways to offset their energy needs. In the fall of 2010, solar panels were installed at the wastewater facility. At their highest output, the panels have produced 75 percent to 80 percent of the facility’s electricity, though on average, factoring in hours of sunlight and storms, the panels have been producing, and will likely continue to produce, around 15 percent of the facility’s power needs on an annual basis.

“We’re trying to be energy-conscious and make the commitment regarding greenhouse gases, while being fiscally efficient. That makes sense to us,” Douville says.

Their next project isn’t one that’s energy-conscious, but it is taking the toxicity of chemicals into account.

One of the last steps in decontamination is to rid the water of bacteria and other pathogens that are present in high levels. Currently, the center uses gaseous chlorine to disinfect the water of these pathogens.

“It’s very effective but is extremely toxic to aquatic life and a huge safety risk to city staff and residents nearby, if we had a leak or tank rupture. That’s a low-probability event, but still a realistic risk scenario that we face,” Douville says.

The center uses a second gas to dechlorinate and remove residual chlorine, so that toxins aren’t released into the stream, but both of those gases will be replaced with a UV disinfection system.

“It’s a focused, targeted wavelength of high energy that only takes a matter of seconds to disinfect the wastewater and achieve compliance with our regulations,” Douville says.

It will take more power, but will be significantly safer to aquatic life and the staff in close contact with the chlorine gases. The project is currently out for bid. Douville says he hopes to start construction on the project this summer.

The facility offers public tours.

For more information, call 303-413- 7340.