Carollo Engineers' Biottta Project Wins ACEC Award

Feb. 3, 2016
Project allowed city of Delano, Calif. to remove nitrates from well

The American Council of Engineering Companies recently announced their 2016 Engineering Excellence Awards, selecting Carollo Engineers as an Honor Award winner for the Delano biottta Wellhead Nitrate Treatment Demonstration Project.

In April of 2014, California approved a grant-funded project to help provide the City of Delano with safe drinking water. The $5 million grant allows the city to remove one of California’s most widespread groundwater contaminants: nitrates. It funded a three-year pilot and demonstration project for the removal of nitrate from drinking water, and Delano subsequently installed and began operating a biottta (biologically-tailored, two-stage treatment approach) nitrate system in the fall of 2015. This system, designed by Carollo Engineers, is used on municipal supply well 35, which produces water exceeding the required safety levels for nitrates.

The city has sufficient water supply to meet demand, but the supply well requiring treatment was needed to ensure future supply. Carollo’s biottta process uses naturally occurring bacteria to treat a range of groundwater contaminants, while eliminating traditional, environmentally harmful waste streams, increasing water recovery rates and reducing treatment costs. The city needed a nitrate treatment system that doesn’t produce a nitrate-laden concentrated waste stream, requires limited operator attention and is cost-effective.

Responding to these needs, the extended pilot study showed that the biottta treatment system efficiently degrades nitrate to harmless nitrogen gas, avoiding the generation of a concentrated waste stream. The pilot also demonstrated the automated nature of the treatment system, which limits manual operation demands. Finally, piloting confirmed the anticipated design and operating criteria, ensuring a cost-effective solution for the city. The system also removes nitrate from groundwater without producing a concentrated waste stream. As a result, the city’s future operations and maintenance costs will be economical, compared to conventional phase separation technologies that produce a brine waste.

The three-year project consisted of a 10-month pilot study, and it will provide 12 months of full-scale operational data to refine and confirm the long-term economic benefits that can be realized by the city and other communities in similar situations. With the process in place, the city has a treatment facility that ensures that well 35 is an integral part of its water supply.

Source: Carollo Engineers