The technical and economical feasibility of alternating current electrocoagulation (ACE) was evaluated for a 2-year period. ACE is an electrochemical technology where highly-charged aluminum polyhydroxide species are introduced into aqueous media for the removal of suspended solids, oil droplets, and soluble ionic pollutants. ACE can break stable aqueous colloidal suspensions of up to 10% total solids and stable emulsions containing up to 5% oil. Major operating parameters have been defined for different classes of effluents based on experimental results using complex synthetic soil slurries and metals. Test results indicate that ACE produces aqueous and solid separations comparable to those produced by chemical flocculent additions, but with reduced filtration times and sludge volumes. The technology has application where removal of soluble and suspended pollutants from effluents is required, and in the recovery of fine-grained products from process streams. The technology however, has not yet been demonstrated at full-scale for Superfund site remediation. Summarized are the principal results of the SITE research program and results of ACE treatment on some different classes of industrial effluents, not part of the SITE Program.