NOVELTY - Treating tailings, involves: pre-treating the tailings; electrolytically treating the pre-treated tailings; separating solids from liquids from the pre-treated tailings; and filtering the separated liquids to result in a filtrand and a filtrate comprising the treated tailings.    USE - For treating tailings useful for producing energy in a fuel cell or combustion device (claimed), where the tailings include tailings from oil sands operations.    ADVANTAGE - The method removes and/or destroys pollutants at lower hydraulic retention times than in conventional biological or physical-chemical systems. The method removes 80 to 98% of the pollutants in the tailings. It has a hydraulic retention time of 3 to 60 minutes and power requirements around 0.5 to 40 kWh/m3. The method reduces the amount of residual bio-solids, thus reduces additional treatment or disposal. Off gas can be produced during the treatment, and can be separated and purified. The separated and purified off gas can be used to produce energy in a fuel cell or combustion device, used to produce energy to be sold back to a utility company or another user of electricity, consumed in the process. It removes organic contaminants and reduces toxicity of the tailings input at the same time that fine tailings are being precipitated; reduces toxicity, converts ammonia to nitrogen gas, and/or reduces the level of pathogens in the tailings. Moreover, because of the non-biological character of the solids, there is generally no need for digesters, thus eliminates the production of methane or mercaptans.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for a system for treating tailings, comprising: a pre-treatment system for pre-treating the tailings; an electrolytic treatment system for electrolytically treating the pre-treated tailings; a separation system for separating, in the electrolytically treated tailings, separating solids from liquids; and a filtering system for filtering the separated liquid to result in a filtrand and a filtrate comprising the treated tailings.