The present invention relates to a method for direct treatment of liquid
wastes containing up to 10% or 100,000 mg/L of arsenic by
solidification/stabilization in a relatively cost effective and
environmentally safe. The method also permits the simultaneous
utilization other heavy metal bearing wastes (such as spent catalysts),
in the solidification/stabilization of liquid wastes containing very high
concentration of arsenic. It also deals with a method for converting
liquid wastes containing very high concentration of arsenic into a
non-leachable solid residue ready for final disposal. The direct
treatment of liquid wastes containing very high concentration of arsenic
by solidification/stabilization will eliminate the additional stage of
converting liquid wastes to solid or semi-solid form prior to
solidification/stabilization, thereby significant reduction in overall
cost associated with arsenic waste treatment.