Onsite at the JHWWTF, 200-gallon plastic tanks are home to an army of algae thriving in wastewater and monitored by the NMSU research team.

Cassie McClure and Suzanne Michaels report for KRWG that, over the past decade, New Mexico State University (NMSU) College of Engineering Professor Nagamany Nirmalakhandan (known as Dr. Khandan) has been investigating how algae removes contaminants from wastewater.

The specific microalgae used by Dr. Khandan and his team of graduate students comes from hot springs in Yellowstone National Park and can thrive in 110-degree temperatures while consuming organic carbon, nitrogen, and phosphorous found in wastewater. By doing that it cleans wastewater making it suitable for discharge into waterways.

The algae’s chemical reactions are fueled by the sun — free and abundant in southern New Mexico. However, over the last six months, this team has observed an unexpected and dramatic new result. The algae also destroy potentially disease-causing pathogens in wastewater.

Traditionally, municipal wastewater treatment facilities have added chlorine to kill pathogens in the wastewater. Yet over the last ten years, researchers have discerned a negative side effect. The chlorine has the potential to form carcinogenic by-products.

“Our team found that the algae fight for dominance in our system,” said Dr. Khandan, “And (that) potentially changes the belief that scientists have previously held regarding how algae can operate.”

This research is possible thanks to the collaboration between Las Cruces Utilities (LCU) and the NMSU College of Engineering. The Jacob A. Hands Wastewater Treatment Facility (JHWWTF) in Las Cruces processes an annual 3.3 billion gallons of sewage from the community’s sinks, showers, and toilets. “This research has global implications for wastewater management in sunbelt regions that are hot and dry,” said Dr. Khandan.

Along with NMSU faculty member Dr. Yanyan Zhang, whose research interest includes pathogen detection and inactivation, and students Himali Delanka-Pedige and Srimali Munasinghe-Arachchige, both NMSU Master’s graduate students in their second semester, Dr. Khandan wants to now try and figure out the exact mechanisms by which algae seeks out and destroys the pathogens.

“It’s been exciting to see something we’re doing go from theory to the lab to something practical,” said Himali. Srimali agrees and sees the future, “If this can be implemented on the large scale, it will be incredibly cost effective.”

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