Bleaching earths are the most important
processing aid utilized in the refining of edible oils. The handling, disposal, and use of the
spent bleaching earth has historically been considered problematic.
The main issues are the potential for spontaneous combustion of the spent bleaching earth (SBE),
and the leaking of entrained oily materials from the SBE into ground water at landfill sites.
According to the Malaysian Palm Oil Council (MPOC), global edible oil production in 2014 was
tonnes. For an average bleaching earth consumption of 0.5% of the weight of the oil, this would
equate to at least one million tonnes per annum of spent bleaching earth.
Dr Patrick Howes is the technical director at
Natural Bleach Sdn Bhd, Malaysia