Fluidized bed wastewater treatment apparatus
AssigneeThe University of British Columbia
InventorsFred A. Koch, Donald S. Mavinic, Noboru Yonemitsu, Ahren Thomas Britton
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Abstract
A fluidized bed reactor for removing phosphorus and nitrogen from wastewater has a column comprising a number of sections. The diameter of the column changes stepwise between the sections. A flow velocity in excess of 100 cm/min is maintained in a lowermost one of the sections and lower flow velocities are maintained in subsequent sections. A struvite supersaturation ratio is controlled in part by recycling wastewater from an outlet of the column. Struvite pellets are removed periodically from the bottom of the column.
Claims39
A fluidized bed reactor for use in removing solutes from wastewater, the reactor comprising
- a column comprising a substantially vertically oriented conduit having a harvesting section and at least two vertically sequential sections located above the harvesting section, a cross sectional area of the conduit increasing between adjacent ones of the sections;
- an inlet for wastewater in the column in or below the harvesting section;
- a recycling path extending from an outlet in an upper portion of the conduit to the inlet;
- and,
- a controller configured to control a supersaturation ratio for struvite, a struvite analog, or a phosphate compound to have a value within a desired range within the harvesting section by, at least in part, controlling a recycling ratio of a rate at which wastewater is being introduced into the column by way of the recycling path to a total rate at which wastewater is being introduced into the column
- wherein, in operation of said reactor, pellets comprising crystals of struvite, the struvite analog or the phosphate compound form a fluidized bed in the column and grow from said solutes, and said pellets are capable of being extracted from said harvesting section.
Apparatus for deriving phosphorus-containing solids from wastewater, the apparatus comprising:
- a vessel having a recycling path extending from an upper portion of the vessel to an inlet in a lower portion of the vessel, the upper portion of the vessel having a cross-sectional area greater than a cross-sectional area of the lower portion of the vessel;
- a pump connected to generate a flow of wastewater through the recycling path;
- a controller configured to control a supersaturation ratio for the phosphorus-containing solid in a zone within the vessel at least in part by controlling a ratio of the flow of wastewater through the recycling path to a total flow of wastewater through the vessel
- wherein, in operation of said apparatus, pellets comprising crystals of struvite, the struvite analog or the phosphate compound form a fluidized bed in the column and grow and said pellets are capable of being extracted from said lower portion.
A fluidized bed reactor comprising:
- a column comprising a substantially vertically oriented conduit having a harvesting section in a lower portion thereof, the conduit configured such that a cross sectional area of the conduit increases with elevation above the harvesting section;
- an inlet port in the column in or below the harvesting section;
- a recycling path extending from an outlet in an upper portion of the conduit, the recycling path reentering the conduit in or below the harvesting section;
- and,
- a controller configured to control a supersaturation ratio for struvite, a struvite analog, or a phosphate compound to have a value within a desired range within the harvesting section by, at least in part, controlling a recycling ratio of a rate at which wastewater is being introduced into the column by way of the recycling path to a total rate at which wastewater is being introduced into the column
- wherein, in operation of said reactor, pellets comprising crystals of struvite, the struvite analog or the phosphate compound form a fluidized bed in the column and grow and said pellets are capable of being extracted from said harvesting section.
Dependencies are inferred from the claim text.