Oklahoma State University researchers are evaluating ozone nanobubble technology as a potential tool for removing antibiotics and antibiotic resistance genes from livestock wastewater.
The project, led by Dr. Kiranmayi Mangalgiri of OSU's Department of Biosystems and Agricultural Engineering, aims to develop scientifically backed guidelines for using the technology to reduce the environmental spread of antibiotic resistance while improving wastewater treatment practices for livestock producers.
Antibiotic use in livestock can leave traces of medications and genetic material associated with antibiotic resistance in farm wastewater. If the wastewater is not adequately treated, those contaminants can move beyond farms and contribute to the spread of antimicrobial resistance.
Traditional municipal wastewater treatment plants are designed primarily to remove nutrients such as nitrogen and phosphorus and are not intended to eliminate many pharmaceutical compounds. Agricultural wastewater can be more difficult to treat because contaminant concentrations can be significantly higher than those found in household wastewater.
Mangalgiri's team is studying ozone delivered through nanobubbles rather than conventional ozonation. The bubbles are about three orders of magnitude smaller than those used in typical diffused aeration systems. Their small size allows them to remain suspended in water longer, giving more ozone an opportunity to dissolve into wastewater rather than escape into the atmosphere.
The interdisciplinary research team includes Dr. Mark Krzmarzick, head of OSU's School of Civil and Environmental Engineering. Researchers will first evaluate the technology under controlled laboratory conditions before testing it with wastewater collected from swine farms.
The team will measure the process's effectiveness in removing antibiotic compounds and breaking down antibiotic resistance genes that can be transferred between bacteria.
Those genes are a major focus of the research. Even after bacteria die, fragments of their genetic material can remain in wastewater. Other bacteria can acquire antibiotic resistance from that material, allowing resistance to spread without direct reproduction.
By breaking down the genetic material, researchers hope to reduce one pathway through which antibiotic resistance can spread through the environment. Krzmarzick's laboratory can analyze genetic material associated with antibiotic resistance, allowing the researchers to determine whether ozone nanobubbles can break down resistance genes before they are transferred to other bacteria.
The project also will examine how wastewater characteristics, including salt, nitrogen and organic matter, affect nanobubble performance. The goal is to establish data that can help producers and future treatment facilities predict how the technology will perform under different conditions.
Researchers also hope the technology could help rural communities by reducing environmental contamination and lowering treatment costs through more efficient ozone use.
If successful, the research could provide a foundation for larger-scale treatment systems designed to improve water quality, support sustainable agriculture and help slow the environmental spread of antibiotic resistance.
Source: Oklahoma State University, "OSU researchers explore nanobubble technology to help curb spread of antibiotic resistance from agricultural wastewater"