Ozonation of swine manure wastes to control odors and reduce the concentrations of pathogens and toxic fermentation metabolites

• Published in: Ozone: science & engineering 1997, Vol.19 (5), p.425-437
• Main Authors: Watkins, Bruce D., Hengemuehle, Susan M., Person, Howard L., Yokoyama, Melvin T., Masten, Susan J.
• Format: Article
• Language: English
• Subjects: Applied sciences; Bacteria; Exact sciences and technology; Hydrogen sulfide; Manures; Metabolites; Odor Control; Odors; Other wastewaters; Ozonation; Ozone; Ozonization; Phenolic Compounds; Pollution; Swine Manure; Wastewaters; Water treatment and pollution
• ISSN: 0191-9512; 1547-6545
• DOI: 10.1080/01919512.1997.10382869

The use of ozone for the remediation of nuisance odorous chemicals in liquid swine manure slurry was investigated. Gaseous ozone was bubbled directly into stored swine manure slurry in a continuously stirred batch reactor. One-liter samples of swine slurry were ozonated to achieve ozone dosages of 1.0, 2.0 and 3.0 g ozone/liter of waste. Olfactometric determinations demonstrated a significant reduction in odors in ozonated samples as compared to raw and oxygenated samples. Volatile fatty acids, nitrate, phosphate and ammonia concentrations were unchanged by ozonation. The biochemical oxygen demand (BOD) and the chemical oxygen demand (COD) were essentially unaffected by ozonation. The concentrations of odorous phenolic microbial metabolites (e.g., phenol, p-cresol and p-ethylphenol) and odorous indolic microbial metabolites (e.g., 3-methylindole and indole) were reduced to non-detectable levels by ozonation. Hydrogen sulfide concentrations were reduced slightly by the process, with a concurrent increase in the sulfate concentration. E. coli counts were reduced by a factor of three log units and total coliforms showed a one log decrease in concentration after treatment with ozone at 1.0 g/L. The results of this study demonstrate clearly that at the pH values studied (ca. 7), ozonation is effective for the elimination of the malodors associated with stored swine slurry and for killing potentially pathogenic bacteria, without increasing the concentrations of major pollutants of current concern, (i.e., nitrate and phosphate) and without oxidizing ammonia, which is a major plant nutrient.