Hybrid aerobic and anaerobic wastewater and sludge treatment systems and methods
AssigneeSiemens Water Technologies Corp.
InventorsWenjun Liu, Edward John Jordan, George W. Smith
Life of this patent
Estimating the term…
Abstract
A hybrid method and system of treating wastewater with reduced energy usage is disclosed. The treatment system has a sorption system, an anaerobic digester that digests or converts at least a portion of the solids or sludge from the sorption system, and an aerobic treatment tank that partially reduces oxygen demand of a portion of the sludge from the sorption tank.
Claims38
A process for treating wastewater comprising:
- providing wastewater comprising dissolved and suspended solids;
- promoting aggregation of at least a portion of the dissolved and suspended solids to produce a first mixed liquor;
- separating the first mixed liquor into a first solids-lean portion and a first solids-rich sludge;
- anaerobically digesting a first portion of the first solids-rich sludge to produce an anaerobically digested sludge;
- separating the anaerobically digested sludge into a second solids-lean portion and a second solids-rich sludge;
- precipitating one of a phosphorous containing compound and a nitrogen containing compound from the second solids-lean portion;
- and
- combining a portion of the second solids-rich sludge with the wastewater.
A wastewater treatment system comprising:
- a first treatment unit comprising one of a biological sorption tank, an aerobic treatment tank, an anoxic treatment tank, and an anaerobic digester, the first treatment unit having a treatment unit inlet and a mixed liquor outlet;
- a first separator having a first separator inlet in fluid communication with the mixed liquor outlet, a first solids-lean fluid outlet, and a first sludge outlet;
- an anaerobic digester having a digester inlet in fluid communication with the first sludge outlet, and a first digester outlet;
- a second separator having a second separator inlet in fluid communication with the first digester outlet, a second solids-lean fluid outlet, and a second sludge outlet, the second sludge outlet in fluid communication with the treatment unit inlet;
- and
- a precipitation vessel in fluid communication with the second solids-lean fluid outlet.
A method of increasing the capacity of a wastewater treatment system having a biological treatment train with at least one biological reactor selected from the group consisting of an anaerobic reactor, an anoxic reactor, and an aerobic reactor, a solids-rich outlet of the biological treatment train fluidly connected upstream of an inlet of an anaerobic digester, and a recycle line fluidly connecting an outlet of the anaerobic digester to an inlet of the biological treatment train, the method comprising:
- adjusting a fraction of a solids-rich sludge produced in the biological treatment train directed to the inlet of the anaerobic digester to a level at which a concentration of methanogenic bacteria present in the solids-rich sludge produced in the biological treatment train is a substantial fraction of a concentration of methanogenic bacteria present in mixed liquor in the anaerobic digester.
Dependencies are inferred from the claim text.