Use of Carbonate and Alkali To Eliminate Escherichia coli from Dairy Cattle Manure

A procedure to eliminate Escherichia coli in dairy cattle manure was developed. E. coli persisted in fresh manure and farm storage tanks, and viable counts ranged from 105 to 108/g. If the feces to urine ratio of fresh manure was decreased from 2.2 to 1, E. coli did not persist for ≥10 days (<10 viable cells/g), and it appeared that the urine was killing E. coli. Fecal urease contamination produced CO2, and 16% was trapped as carbonate. When urine pH was decreased, antimicrobial effect was lost, even if the pH was readjusted to 8.5. When E. coli K-12 and O157:H7 were treated with Na2CO3 (100 mM, pH 8.5, 24 h), viable cells were not detected. The E. coli count of manure (feces to urine ratio of 2.2:1) was decreased by Na2CO3 addition (8 g/kg), but pH sometimes declined and carbonate was lost. When NaOH was included (2 g/kg), Na2CO3 additions could be decreased (4 g/kg), and treatment time was 5 days. Treatment cost could be <$10 year-1 (dairy cow)-1. Water dilution (3-fold) did not diminish the effectiveness of the carbonate/alkali treatment, and viability was <10 cells/g.