Patent ID: 8377221

Claim:
A method of cleaning a vault comprising the steps of: using a coupling mechanism to couple a source of suction with a vacuum head in a vault; initiating the application of suction, and then continuing the application of suction in the vault, to substantially empty the vault of water and contaminants, wherein the application of suction is performed using the source of suction and the suction is applied to the vacuum head to suction the water and contaminants into the vacuum head from an interior of the vault; and wherein the initiating the application of suction to substantially empty the vault of water and contaminants is performed under the following conditions: the vault comprises a vault floor, a cover, and at least one wall that define the interior of the vault; the interior of the vault comprises contaminated water and contaminants adhering to the vault floor; the contaminated water has a water surface that is at least one foot from a most distant point on the vault floor; and the vacuum head is in contact with the vault floor, and at least a portion of the vault floor slopes toward the vacuum head; wherein the source of suction is also a source of force which back flushes water through the vacuum head and into the interior of the vault, and wherein the method further comprises: before substantially emptying the vault of water and contaminants, alternating between applying suction to the vacuum head and back flushing previously removed water from the vault, the alternating being performed to maintain a height of the water surface at greater than ten feet from the most distant point on the vault floor, wherein: applying said suction to the vacuum head removes a portion of the water and contaminants adhering to the vault floor and back flushing loosens some of the contaminants adhering to the vault floor; and the alternating is performed under the same conditions as the initiating the application of suction to substantially empty the vault of water and contaminants.