Anyone living near the Tijuana River knows the challenges it has brought to San Diego communities for decades. Recently, a midwestern water technology company proved that, even with the most intractable problems created by humans and complicated by nature, innovation can flow toward success.
Once described as the most polluted river on the U.S.-Mexico border, the Tijuana River has long struggled with dire water quality issues caused by untreated and partially treated wastewater, stormwater runoff and industrial discharges flowing north from Mexico. The river, which empties into the Pacific Ocean near Imperial Beach in San Diego County, is an ongoing source of frustration for nearby communities, where cross-border pollutants have led to frequent beach closures and damage to sensitive habitats.
The Tijuana River isn’t alone. More than five decades after passage of the Clean Water Act, the Environmental Protection Agency says that a large portion of U.S. rivers and streams, perhaps half, are impaired by contamination and fail to meet water quality standards.
After previous mitigation efforts, the latest to tackle pollution in the Tijuana River was spawned by the International Boundary and Water Commission (IBWC), which facilitated a $1.1 million pilot project and engaged Greenwater Services, a Brookfield, Ohio-based technology company.
“We were able to obtain the pilot because there’s no other company that does what we do at the capacity that we do it,” said Greenwater CEO Al George.
The IBWC oversaw the project, which was conducted over a five-week period late last year, leveraging Greenwater’s patented Nano Bubble Ozone Technology (NBOT). A natural water disinfecting system, NBOT is designed to reduce deadly algal blooms and pathogens without harming marine life. NBOT has been tested and validated by a breadth of research institutions and government agencies, including the National Oceanic and Atmospheric Administration (NOAA) and the Ohio State University.
The pilot program deployed four NBOT units at the flood control plain west of the border with Mexico. “We averaged 91.5% reduction in total coliform bacteria, a key water quality indicator, on the days that we treated, which is quite remarkable,” George said. Border Patrol Agents stationed near the treatment site also commented on the decrease in foul odors, which normally plague the river.
One notable challenge was a large volume of plastic and other trash in the river, which led Greenwater to run its NBOT units only during daytime hours when the river flow was lower in order to reduce the risk of clogging. This shorter operational window allowed the company to evaluate treatment performance under more stable conditions.
Greenwater’s Nano Bubble Ozone Technology is as much about safety as it is efficacy. “With this system, none of the ozone goes into the air,” said Peter Moeller, PhD, a NOAA research chemist who has consulted with Greenwater on the science behind its technology. “In fact, it leaves the water more oxygenated after attacking bacteria and dissolved contaminants.”
The company acknowledges that local frustration about the Tijuana River problem led to high expectations from the onset, as well as a misunderstanding that the pilot was intended to treat the entire river, rather than prove the technology’s effectiveness in just a small section. By that measure, the pilot indeed proved successful in reducing harmful bacteria by 91.5%, far exceeding the project’s initial 15-20% objective.
While levels were still higher than acceptable for human contact, this was expected because the pilot utilized only four NBOT units in a sample section of the Tijuana River. For large-scale impact that met rigorous safety standards, the company says that ten times the number of units would have been needed.
Recently in the wake of the pilot project, Greenwater prepared a report for the IBWC with key recommendations for scaling up treatment of the Tijuana River. They include deploying close to 40 NBOT units in order to handle anticipated daily flow volumes and integrating a filtration system to screen trash and enable continuous 24/7 operation.
Greenwater’s technology is being employed for other public water purification efforts across the U.S., including a Florida Department of Environmental Protection project, in collaboration with NOAA, beginning in April to reduce phosphorus and nitrogen in two of its lakes, and two additional Florida projects in partnership with the Ohio State University and the University of Florida.
Said Greenwater Services CEO Al George, “We want to offer governments and communities a viable and safe solution for improving water quality to benefit public health, as well as the environment and local economies.”
