Abstract: An apparatus and method for removing contaminants from contaminated water. One embodiment of the apparatus comprises a separation tank in which a first portion of the contaminants float to the top of the water, the tank including a water inlet and a water outlet, a coalescing device, an air injection system in which water from the tank is pressurized, passed through an air eductor so as to receive air bubbles, and returned to the tank as a gas-containing stream, a circulating mop that contacts the floating contaminants and removes them from the water, the circulating mop comprising a continuous loop of contaminant-absorbing material, a mop-cleaning member that removes contaminants from the circulating mop, and a filter system through which water leaving the separation tank via the water outlet is passed.