Self Contained Dissolved Air Flotation System

Abstract

A dissolved air flotation system and method for purifying fresh water. The system is self-contained within a standard shipping container, with all components disposed in-line within the shipping container. Float is removed from the flotation tank with a skimmer that drives float downstream onto a conveyor belt, and the conveyor belt conveys float away from the flotation tank, in the downstream direction, and deposits the float in a collection tank. Clean water may be drawn from the flotation tank continuously, while float may be removed periodically.

I claim: 
     
         1 . A method of purifying influent water comprising the steps of:
 providing a flotation tank having an upstream end and downstream end;   introducing the influent water into the flotation tank via an influent water port in fluid communication with the flotation tank and mixing the influent water with a stream of water containing a large amount of dissolved air;   providing a skimmer disposed above the flotation tank that extends transversely across the flotation tank;   periodically driving the skimmer from an upstream end of the flotation tank to a downstream end of the flotation tank and pushing float, that is generated when bubbles produced when the dissolved air attaches to flocculent grown in the influent water, over the downstream end wall of the flotation tank, the skimmer driven at a rate of 1.5 feet per minute;   providing a conveyor belt disposed proximate the downstream wall of the flotation tank;   operating the conveyor belt to convey float away from the flotation tank, in the downstream direction;   providing a float collection tank disposed relative to the conveyor; and   providing an output manifold disposed in the lower portion of the downstream end of the flotation tank for drawing clean water from the flotation tank.   
     
     
         2 . The method of  claim 1  further comprising the steps of:
 providing a clean water output means for drawing clean water from the flotation tank; and 
 programming the control system to continuously operate the clean water output means during operation of the system to draw clean water from the flotation tank. 
 
     
     
         3 . The method of claim system of  claim 2  further comprising the steps of:
 providing a level control that controls the water level in the flotation tank; and 
 programming the a control system to operate the level control means during operation of the system, to overfill the flotation tank so that water level rises above the downstream end of the flotation tank prior to skimming and lowers the water level in the flotation tank to a level below the downstream end of the flotation tank after skimming. 
 
     
     
         4 . The system of  claim 2  further comprising the steps of:
 providing a level control means for controlling the water level in the flotation tank; and 
 programming the control system to operate the level control means during operation of the system, to overfill the flotation tank so that water level rises above the downstream end of the flotation tank prior to skimming and lowers the water level in the flotation tank to a level below the downstream end of the flotation tank after skimming.