Abstract: The device for reducing the volume of an aqueous waste effluent includes a holding tank, a heating tank for receiving waste effluent from the holding tank and including a heater for heating the waste effluent to a predetermined temperature which is below the boiling point of water and high enough to cause a portion of the water to evaporate and be discharged as water vapors, an agitation pump for continuously recirculating the liquids contents of the heating tank and filter units mounted on top of the heating tank for separating solids and particulate matter from the resulting slurry and returning the filtrate to the heating tank.