Method for treating water

A method of treating a bounded body of water with a propeller type aerator comprising the steps of:

• (a) aerating a bounded body of water with a plurality of propeller type aerators, each aerator having a hollow tube with opposite ends, a longitudinal axis extending between the ends and a propeller adjacent one of said ends, said propeller being rotatably driven and said end of the tube adjacent the propeller including means for injecting air into the water;
• (b) placing each of said aerators into a bounded body of water with said propeller and tube end adjacent thereto below the top surface of said water and with the longitudinal axis of each aerator disposed at an angle below the horizontal;
• (c) arranging and driving a first of said aerators to induce a first fluid flow path about said first aerator, said first fluid flow path having forward horizontal flow vectors in a direction forward of the propeller of said first aerator, negative horizontal flow vectors in a direction toward the propeller of said first aerator from an area rearward of said last-mentioned propeller, and a diffuse horizontal flow field interconnecting the forward and negative flow vectors;
• (d) arranging and driving a second of said aerators to induce a second fluid flow path about said second aerator, said second fluid flow path having forward horizontal flow vectors in a direction forward of the propeller of said second aerator, negative horizontal flow vectors in a direction toward the propeller of said second aerator from an area rearward of said last-mentioned propeller, and a diffuse horizontal flow field interconnecting the forward and negative flow vectors of said second fluid flow path;
• (e) disposing said first aerator relative to said second aerator so that at least some of the negative flow vectors of said second aerator link with at least some of the forward flow vectors of said first aerator to create an overall flow path in the general direction of the forward flow vectors of said first and second aerators;
• (f) injecting oxygen from the ambient air through the tubes of said aerators into the body of water at a rate greater than 1 pound of oxygen per horsepower-hour;
• and
• (g) inducing by means of the propellers of said aerators the overall flow path of the water having an average linear velocity through a cross-section to flow at least 0.25 feet per second, said angle of inclination of each aerator being sufficient to accomplish the injection rate of step (f) and the average linear velocity of step (g).