Method and system for utilizing activated sludge in a ballasted flocculation process to remove BOD and suspended solids

A wastewater treatment system, comprising:

• an activated sludge system including at least one reactor, a clarifier and a return activated sludge line for conveying return activated sludge from the clarifier to the reactor to form mixed liquor;
• a ballasted flocculation system having one or more tanks and a settling zone and disposed is a non-series relationship with the activated sludge system;
• and
• a mixed liquor supply line connected between the activated sludge system and the ballasted flocculation system for transferring at least a portion of the mixed liquor directly to the ballasted flocculation system.

A method of treating wastewater utilizing an activated sludge system and a ballasted flocculation system to remove soluble BOD from the wastewater being treated, the method comprising:

• directing the wastewater into and through an activated sludge system having at least one reactor and a clarifier;
• returning activated sludge from the clarifier to the reactor and mixing the activated sludge with the wastewater to form mixed liquor;
• directing a portion of the mixed liquor through the activated sludge system and to the clarifier where the clarifier produces a first clarified effluent;
• directing another portion of the mixed liquor from the activated sludge system to a ballasted flocculation system disposed in parallel relationship with the clarifier of the activated sludge system;
• directing the other portion of the mixed liquor through the ballasted flocculation system wherein the ballasted flocculation produces a second clarified effluent;
• wherein substantially all of the wastewater that forms a part of the mixed liquor that is treated in the ballasted flocculation passes through at least a part of the activated sludge system prior to entering the ballasted flocculation system;
• and
• wherein the clarifier of the activated sludge system and the ballasted flocculation system clarifies the wastewater being treated, and wherein the activated sludge that forms a part of the mixed liquor is effective to remove soluble BOD from the wastewater that forms a part of the mixed liquor that passes through both the activated sludge system and the ballasted flocculation system therein.

A method of treating wastewater utilizing an activated sludge system and a ballasted flocculation system to clarify the wastewater and remove soluble BOO from the wastewater, the method comprising:

• directing substantially all the wastewater to be treated into an activated sludge system having at least one reactor and a clarifier;
• returning activated sludge from the clarifier to the reactor and mixing the activated sludge with the wastewater to form mixed liquor;
• directing a portion of the mixed liquor through the activated sludge system and to the clarifier where the clarifier produces a first clarified effluent;
• directing another portion of the mixed liquor from the activated sludge system to a ballasted flocculation system disposed in a non-series relationship with the activated sludge system;
• clarifying the other portion of the mixed liquor in the ballasted flocculation system to produce a second clarified effluent;
• and
• removing soluble BOD from the wastewater that passes through both the activated sludge system and the ballasted flocculation system.