Bench scale experiments were performed to determine the effect of adding various amounts of the product Biosafe to swine manure. In particular, it was desired to determine if addition of Biosafe would: reduce the odour, reduce the volatile solids concentration, and have any effect on the total nitrogen, ammonium-N, nitrate-N, total phosphorous, or total potassium concentrations in the manure. Two groups of panellists evaluated the odour after 3 and 6 days of treatment. The most important conclusions are listed below. (1) The smallest amount of Biosafe that provided a substantial reduction in odour was 1 L of Biosafe to 10,000 L manure. The average odour score was reduced by 29% after 3 days of treatment, and 36% after 6 days of treatment. (2) Addition of Biosafe did not affect the amount of volatile solids, phosphorous, or potassium in swine manure. (3) The total nitrogen (TN=TKN+NO3–N) was not significantly altered by the addition of Biosafe. However, 31% of the TN was lost in 6 days of mixing. The loss was by means of volatilization. (4) The air entrained by mixing and the effect of Biosafe at concentrations sufficient to reduce odour elevated the nitrate levels in the manure by a factor of 2.47.