Location: Livestock Bio-SystemsTitle: The efficacy of three diatomaceous earth sources for removing tylosin from aqueous systems
Submitted to: Journal of Environmental Quality
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/25/2019
Publication Date: 11/1/2019
Publication URL: https://handle.nal.usda.gov/10113/6829249
Citation: Stromer, B.S., Woodbury, B.L., Williams, C.F. 2019. The efficacy of three diatomaceous earth sources for removing tylosin from aqueous systems. Journal of Environmental Quality. 48(6):1863-1871. https://doi.org/10.2134/jeq2018.11.0409.
Interpretive Summary: Tylosin is a widely used antibiotic fed to animals to maintain herd health during livestock production. A majority of the antibiotic passes through the animal undigested and enters the environment. There is concern these antibiotics could make medicines used to treat human infections less effective. Previously, it was shown that a soil mineral could be used to sorb tylosin from wastewater. In this paper, we considered different types of soil minerals and evaluated their efficiency for tylosin removal. We concluded tylosin is best removed by the unprocessed soil mineral. Also, it was found the presence of clays improves tylosin removal. This paper details the most effective use of clay mineral for removing antibiotics from beef cattle wastewater storage ponds. Removal of antibiotics from agricultural wastewater can reduce the potential for antimicrobial resistance in humans.
Technical Abstract: Antibiotics used during animal production are the same or very similar to antibiotics used by humans. Tylosin, structurally similar to erythromycin prescribed to humans, is a common livestock antibiotic. Therefore, tylosin and other similar antibiotics present a potential threat of environmental buildup resulting in increased microbial resistance. To mitigate this potential impact, a remediation method for reducing the load of antimicrobials entering the environment is needed. The binding properties of different types of diatomaceous earth (DE) were investigated for maximum binding and the influencing physical characteristics to determine the potential use as a binding agent for wastewater treatment. Swimming pool DE was 99% crystalline silica and did not sorb any tylosin. Raw DE was 65% amorphous silica, 20% clay, and had 3% organic matter by weight. Langmuir isotherms predicted a maximum binding capacity of 49 ± 3 mg g-1 with a binding constant of 37,342 ± 5653 M-1. This was almost 3.3 times more than previously published work investigating the binding of tylosin to kieselguhr that is 96% amorphous silica with little to no clays or organic matter present. To determine the role of organic matter and clays in binding capacity, raw DE was digested with 3% hydrogen peroxide and adsorption isotherms were constructed. After removal of the organic matter, predicted maximum binding of tylosin increased to 88 ± 2 mg g-1, whereas the binding constant slightly decreased (23,482 ± 3264 M-1). It was concluded that the DE–clay matrix was responsible for high binding and therefore had the greatest potential for application in a wastewater treatment process.