Flotation/fractionation systems for treating liquids and in separation of liquids to be treated thereby

An improved method for controlling the removal of waste such as biosolids, nitrates or nitrites from a liquid containing same using a fractionation/flotation system comprising:

• a fractionation column;
• a foam aggregation chamber surmounting the fractionation column;
• foam extracting means to extract foam collected within the foam aggregation chamber;
• and liquid outlet means for outletting treated liquid from the base of the fractionation column;
• the method comprising:
• inletting liquid containing waste under pressure into the fractionation column at first and second intermediate locations from a common source, the second location being lower than the first location;
• injecting a waste reducing gas such as air, oxygen or ozone into the liquid immediately prior to inletting the same into the fractionation column at the second intermediate location;
• and
• regulating the flow of liquid being inlet at the first intermediate location to maintain the liquid within the fractionation column at an optimum level for enabling foam having waste adsorbed thereto to aggregate in the aggregation chamber.

An apparatus for separating liquid containing particles of varying mass or specific gravity comprising:

• an elongated passageway having:
• (a) a leading wall with a primary lip for liquid containing said particles to flow over into said passageway;
• (b) a trailing wall with secondary lip disposed lower than said primary for liquid to flow over and out of said passageway;
• and (c) a base closing the bottom of said passageway to enable the liquid flowing into the passageway over said primary lip to fill the same and flow out over the secondary lip;
• flow diverting means disposed in said passageway for diverting the liquid flow therein to create a convolving recirculating portion of laminar flow and a discharging portion of laminar flow of liquid within the passageway;
• and
• liquid extraction means to extract liquid containing particles of lower mass or specific gravity entrained within said recirculating portion therefrom, leaving liquid containing particles of waste to flow out of said passageway and over the secondary lip.

A method for separating liquid containing particles of varying mass or specific gravity comprising:

• cascading liquid containing said particles over a primary lip into a passageway;
• diverting the flow of the liquid within the passageway to create a convolving recirculating portion of laminar flow and a discharging portion of laminar flow;
• extracting liquid containing particles of lower mass or specific gravity entrained within said recirculating portion therefrom;
• and
• discharging liquid containing particles of higher mass or specific gravity entrained within said discharging portion out of said passageway over a secondary lip.