Decomposition in Soil of Waste Cooking Oils Used in Potato Processing

Abstract

Abstract Cooking oils used in potato processing are sometimes wasted in small quantities into the effluent that goes to land disposal. To determine the effect of this oil on land, palm and soybean oils were added to Portneuf silt loam at rates of 0.1, 0.5, 1.0, and 5.0 g oil in 100 g soil (2.2, 11.2, 22.4, and 112 metric tons/ha, respectively). Nitrogen was added and the mixtures were incubated at constant temperature in a CO 2 ‐free continuously flowing air stream. Evolved CO 2 was scrubbed from the air stream and decomposition calculated. Both oils decomposed at the same rate at each application rate. Maximum weekly decomposition was approximately 8 and 2.5 metric tons/ha for the 112 and 11.2 metric ton‐applications, respectively. There was no evidence for toxicity to the decomposition systems with the high application of oil and no evidence that difficulty would develop with land disposal of wastes containing these edible cooking oils.