Combined treatment methods for removal of antibiotics from beef wastewater

Authors: Stromer, Bobbi; Woodbury, Bryan; Williams, Clinton; Spiehs, Mindy

Submitted to: ACS Omega
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/15/2024
Publication Date: 12/10/2024
Citation: Stromer, B.S., Woodbury, B.L., Williams, C.F., Spiehs, M.J. 2024. Combined treatment methods for removal of antibiotics from beef wastewater. ACS Omega. 9(49):48721-48726. https://doi.org/10.1021/acsomega.4c08114.
DOI: https://doi.org/10.1021/acsomega.4c08114

Interpretive Summary: Antibiotics used in animal agriculture can potentially be released into the environments where they can cause antimicrobial resistance. Diatomaceous earth, a naturally occurring rock, was tested as a material for removing common livestock antibiotics, tylosin, chlortetracycline and ceftiofur, from wastewater generated from beef production. Further work was done to determine if it could be used in tandem with a common wastewater treatment method, flocculation. Diatomaceous earth was capable of removing tylosin and chlortetracycline when used alone. When combined with flocculation, removal of tylosin remained unchanged and removal of ceftiofur improved. Chlortetracycline was removed by the flocculation process and therefore no assessment of the efficacy of diatomaceous earth after flocculation could be made. This research demonstrates that diatomaceous earth can be used to remove antimicrobials in beef wastewater. Developing mitigations that use diatomaceous earth will help reduce the release of antibiotics into the environment.

Technical Abstract: Use of antibiotics is common practice in agriculture; however, they can be released into the environment, potentially causing antimicrobial resistance. Naturally mined diatomaceous earth with bentonite was tested as a remediation material for tylosin, chlortetracycline, and ceftiofur in wastewater from a beef cattle feedlot. Langmuir binding affinity in 10 mM sodium phosphate buffer at pH 6.7 was established prior to testing wastewater to determine binding potential. Chlortetracycline was found to have a binding affinity of 15.2 mM-1 and a binding capacity of 123 mg per g of diatomaceous earth while ceftiofur showed a much lower binding affinity and loading at 7.8 mM-1 and 3 mg per g of diatomaceous earth, respectively. From spiked wastewater, tylosin (50 µg mL-1, pH 8) and chlortetracycline (300 µg mL-1, pH 6) were removed (100 and 80%, respectively) when treated with 20 mg of diatomaceous earth while ceftiofur (300 µg mL-1, pH 8) remained in solution. When the spiked wastewaterwas flocculated with aluminum sulfate, a change in pH from 8 to 4 was observed, and chlortetracycline was removed from thewastewater; tylosin and ceftiofur remained in solution. When subsequently treated with diatomaceous earth, ceftiofur and tylosinwere completely removed by diatomaceous earth from the flocculated wastewater.