2023 update on the disposal of spent edible oil bleaching earth

Abstract: To achieve a consistent color acceptable to consumers, bentonite clay is used to adsorb pigments and removed by filtration in producing edible vegetable oil. The filtration-removed clay is saturated with vegetable oil about 30% by weight. When exposed to air, the thin film of oil covering the clay crystal surfaces is susceptible to spontaneous combustion from rapid oxidation. Immediate disposal of the oil-saturated clay (spent bleaching earth) is required to avoid the risk of fire. Two disposal methods have long been in common use: (1) hauling and burying in solid waste landfill and (2) adding to and blending with protein meal as an allowed flow agent at a level of 0.2% maximum. Both disposal methods have significant disadvantages. In 2013, a provisional patent was filed to stabilize spent bleaching earth with salt to enable use as an animal feed supplement. In 2015, this disposal method was presented in an Inform article and at the AOCS annual meeting. Another provisional patent was filed in 2015 to stabilize spent bleaching earth with feed-grade lime to enable use in animal and poultry feed. Both spent bleaching earth stabilization methods were presented at the 2018 AOCS annual meetings. Patents covering these stabilization methods have now been issued in 48 countries. Sustainable Feed Innovations LLC was formed in 2020 to globally exploit the patents. The purpose of this presentation is to provide an update on the economic and environmentally sustainability advantages of applying these patent-protected disposal methods for spent edible oil bleaching earth.