Abstract There is disclosed an activated sludge sewage treatment process which comprises mixing influent sewage material with activated sludge and bio-surface particulates to provide a mixed liquor. The mixed liquor is passed to an aeration zone wherein it is contacted with an oxygen-containing gas to reduce the BOD content thereof. The mixed liquor is then passed to a settling zone in which it is settled to separate bio-surface particulates having sludge particles adherent thereto and a clarified supernatant. The clarified supernatant is removed from the settling zone and is discharged as effluent or routed for further treatment. At least a portion of the bio-surface particulates having sludge adherent thereto is subjected to a treatment to separate at least a portion of the adherent sludge particles. The thus treated portion of the bio-surface particulates, which may still have some sludge particles adherent thereto, and separated sludge particles is then passed to a bio-surface particulate sludge separator. In this separator, the sludge present in the mixture which is not adherent to the bio-surface particulates separates from the bio-surface particulates and at least a portion of the sludge is passed out of the system as waste sludge which is essentially free of the biosurface particulates. The bio-surface particulates and remaining sludge are then recycled for mixing with said influent sewage material.
An activated sludge sewage treatment process which comprises mixing influent sewage material with activated sludge and bio-surface particulates to provide a mixed liquor, passing said mixed liquor to an aeration zone wherein it is contacted with an oxygen-containing gas to reduce the BOD content thereof, passing the mixed liquor to a settling zone in which it is settled to separate bio-surface particulates having sludge adherent thereto and a clarified supernatant, removing said clarified supernatant from said settling zine, subjecting at least a portion of the separated bio-surface particulates having sludge adherent thereto to a treatment to separate at least a portion of the adherent sludge therefrom, passing the treated portion of bio-surface particulates and separated sludge to a bio-surface particulate-sludge separator, separating at least a portion of the sludge which is essentially free of bio-surface particulates, removing it from said bio-surface particulate separator and passing it to waste, and recycling the bio-surface particulates and remaining sludge for mixing with said influent sewage material.
Claim 2
Dependent Claim
163 words
An activated sludge sewage treatment process which comprises mixing influent sewage material with activated sludge and bio-surface particulates to provide a mixed liquor, passing said mixed liquor to an aeration zone wherein it is contacted with an oxygen-containing gas to reduce the BOD content thereof, passing the mixed liquor to a settling zone in which it is settled to separate bio-surface particulates having sludge adherent thereto and a clarified supernatant, removing said clarified supernatant from said settling zine, subjecting at least a portion of the separated bio-surface particulates having sludge adherent thereto to a treatment to separate at least a portion of the adherent sludge therefrom, passing the treated portion of bio-surface particulates and separated sludge to a bio-surface particulate-sludge separator, separating at least a portion of the sludge which is essentially free of bio-surface particulates, removing it from said bio-surface particulate separator and passing it to waste, and recycling the bio-surface particulates and remaining sludge for mixing with said influent sewage material.
Claim 3
Dependent Claim
62 words
A process as defined in claim 1 wherein a portion of the separated bio-surface particulates having sludge adherent thereto removed from said settling zone is recycled for mixing with influent sewage material and the remainder of said separated bio-surface particulates having sludge adherent thereto removed from said settling zone is treated to separate at least a portion of the adherent sludge therefrom.
Claim 4
Dependent Claim
14 words
A process as defined in claim 1 wherein said bio-surface particulates are solid particulates.