Tar sand processing waste waters from Syncrude Canada Ltd. and other commercial and experimental operations were treated with a new electrocoagulation process that uses electrical current to destabilize and remove dissolved and suspended materials. The purpose of the treatment is to produce a low-cost environmentally acceptable water for storage reuse or discharge. Bench-scale tests indicate an operating cost of around 34/cubic meter (104/1000 gal). Materials removed from the waste water include dissolved and suspended materials, both organic and inorganic. The electrocoagulation processes removed 99% of the total suspended solids; 65% to 95% of the dissolved (0.45 llIlI filtered) silica. calcium. and magnesium; and 50% to 95% of the total organic carbon. Microtox'" tests indicated a moderate reduction in toxicity after electrocoagulation. Electrocoagulation may provide an inexpensive way of separating solids from tailing. The water could then be stored. discharged or reused. and the solids could be handled separately in a relatively dry form. thus potentially eliminating the need for large tailing ponds.