An Ohio-based startup has been using proprietary water-purification technology to clean the Lincoln Memorial Reflecting Pool.

Greenwater Services, a small company based in Trumbull County, Ohio, has drawn national attention after receiving a $1.7 million federal contract to deploy its NanoBubble Ozone Technology as part of the Trump administration's renovation of the iconic National Mall landmark ahead of America's 250th anniversary.

Greenwater uses a trailer-sized system that injects microscopic ozone nanobubbles into the water to kill algae and other contaminants without chemicals, The Wall Street Journal reported.

The only byproduct is oxygen, making the process environmentally friendly.

By late last week, the Reflecting Pool's once murky green water had largely turned clear after algae blooms that developed following renovations.

"We've got nothing to hide," Greenwater President Chas Antinone Jr. told the Journal, pointing to the pool's improving condition as evidence the technology is working.

The company has become the center of political scrutiny because part-owner John "J.J." Cafaro, an Ohio businessman and longtime friend of President Donald Trump, previously was convicted in two unrelated federal criminal cases decades ago.

The White House and National Park Service have denied Cafaro played any role in Greenwater receiving the no-bid contract, saying the award was based on the urgency of completing work before the July Fourth celebrations.

On Wednesday, The Columbus Dispatch reported Greenwater spokeswoman Erin Kramer expressed frustration that public attention has focused more on politics than the company's technology.

"I just want to set up a table here for people to ask questions about algae," Kramer told the newspaper. "No one wants to talk about the science."

Kramer said technicians have demonstrated bottles of crystal-clear water to reporters while explaining that dead algae settling to the bottom is a normal part of the treatment process.

"Our technology is being deployed in waterways in Ohio and across the country," Antinone said in a statement to the Dispatch, adding the company has collaborated with research universities and environmental agencies.

Greenwater previously tested the same technology on California's sewage-contaminated Tijuana River under a separate federal pilot project.

According to the Journal, the trial demonstrated the system could kill bacteria and eliminate odors, though officials concluded larger equipment would be needed to treat the river's unpredictable flow effectively.

The Reflecting Pool renovation has also faced setbacks.

National Park Service officials confirmed that a liner protecting the bottom of the pool was cut with a sharp object earlier this month, prompting an investigation by U.S. Park Police.

Officials plan to drain the pool after Independence Day festivities to repair the damage.

Despite criticism from Democrats over the no-bid contracts, Greenwater officials say the improving water clarity demonstrates their technology is achieving its intended purpose as preparations continue for the nation's semiquincentennial celebration.

The Associated Press contributed to this report.