Sludge control and decant system

DETAILED DESCRIPTION The system and apparatus which is the subject matter of our invention is intended to overcome the foregoing recited shortcomings of previous systems.
Primarily it consists of a system wherein the growth of microorganisms in sludge is continuously removed in predetermined timed sequence from the system in order to maintain a predetermined concentration of microorganisms therein, so that the microorganism concentration is held at a fixed level, with the total and viable population of microorganisms remaining essentially in the same proportion.
It also provides a system for concentrating the biological sludge prior to discharging to a means of disposal.
In carrying out the method microorganisms are concentrated and a predetermined quantity are disposed of each day.
In order to accomplish this the rate of sludge growth must be determined.
This value may be determined by observing and testing the increase in concentration of microorganisms over a period during which no sludge is removed.
By plotting measurements of sludge concentration over a given length of time, the growth rate of microoganisms is determined.
By determination of the growth rate of microorganisms it can be determined what percentage of the aeration contents may be wasted each day or for other predetermined period of time.
Based upon this determination equipment is provided to remove a predetermined amount of mixed liquor from the aeration tank during such predetermined period of time, and the sludge is allowed to settle, thereby thickening and separating it from excess water.
The excess water is pumped back to the aeration tank and a predetermined amount of sludge is removed from the settling tank in order to maintain the proper balance of microorganisms to waste fluid.
In carrying out the process the settling tank is connected in communication with the aeration tank so as to permit gravity flow of the dilute solution from the aeration tank, having microorganisms suspended therein, to the settling tank as excess water or waste sludge is removed from the settling tank