Conversion of plug flow and complete mix aeration basins to barrier oxidation ditches
OwnerJohn H. Reidinventor
Life of this patent
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Abstract
Methods are provided for converting both plug flow and complete mix basins of the prior art into barrier oxidation ditches. Circulator/aerators are described that can be prefabricated and dropped onto the floor of an existing basin so that, in combination with at least one partition, if needed, an endless channel is created with minimum disruption of the activated sludge process.
Claims25
A method for converting a reactor basin of an activated sludge waste water treatment process, said reactor basin including at least one aerating device, to a barrier oxidation ditch, said method comprising the steps of:
- (a) removing said at least one aerating device;
- (b) forming an endless channel within said reactor basin, said endless channel having substantially parallel sides and a floor;
- and
- (c) placing a single barriered circulator/aerator within said endless channel, said barriered circulator/aerator comprising:
- (1) barrier means for separating mixed liquor within said endless channel into upstream liquor within an intake channel and downstream liquor within a discharge channel, and providing hydraulic support to said downstream liquor;
- (2) a flow passage through said barrier means for providing fluid communication between said intake channel and said discharge channel;
- (3) at least one pump means disposed within said fluid communication passage for propelling said upstream liquor through said passage from said intake channel to said discharge channel, around said endless channel back to said intake channel, and
- (4) at least one aeration means disposed within said fluid communication passage for dispersing an oxygen-containing gas into said propelled upstream liquor to form freshly aerated mixed liquor.
A ducted-barrier circulator/aerator, adapted for prefabrication and installation athwart an endless channel of an oxidation ditch, comprising:
- (a) a barrier adapted to sealingly engage the sidewalls and floor of said endless channel and having a duct horizontally disposed therethrough, said duct having an intake end and a discharge end;
- and
- (b) a mixing and aeration assembly comprising a downdraft tube having a upper end and a lower end which is connected to the intake end of said barrier duct;
- an air sparge device disposed within said downdraft tube;
- and a pump assembly comprising impeller means disposed within said downdraft tube above said air sparge device.
A method for converting a rectangular activated sludge reactor basin, having two long sides, two short sides and a floor therebetween, into a barrier oxidation ditch, said method comprising the steps of:
- (a) prefabricating a barriered circulator/aerator comprising a barrier having spaced-apart side edges, a bottom edge, and a discharge duct disposed therethrough intermediate said side edges, said discharge duct having an axial-flow pump and aeration means disposed therein;
- (b) lowering a partition into said basin and positioning said partition substantially mid-way between said two long sides, said partition having a smaller length than the length of said long sides whereby an endless channel is formed between said partition and each of said long sides and between each end of said partition and each one of said short sides, for conducting mixed liquor therethrough;
- (c) lowering said barriered circulator/aerator into said endless channel so that the side edges of said barrier sealingly engage said partition and one of said long sides and the bottom edge of said barrier sealingly engages said floor, whereby said barriered circulator/aerator divides said endless channel into an intake channel portion and a discharge channel portion;
- and
- (d) operating said axial flow pump and said aeration means so that mixed liquor, in substantially anoxic condition, is pumped from said intake channel through said discharge duct into said discharge channel as freshly aerated mixed liquor which is thereafter circulated around said endless channel back to said barrier circulator/aerator in said anoxic condition.
A method for converting a reactor basin of an activated sludge system to a barrier oxidation ditch, said reactor basin having four sides disposed at right angles and a floor therebetween, said method comprising the steps of:
- (a) prefabricating a barriered circulator/aerator comprising a barrier having spaced apart side edges, a bottom edge and a discharge duct disposed therethrough intermediate said side edges, said discharge duct having an axial-flow pump and aeration means disposed therein;
- (b) lowering a plurality of partitions into said reactor basin for forming an endless channel therein, said channel having a width substantially equaling the distance between the spaced-apart side edges of said barrier;
- (c) lowering said barriered circulator/aerator into a position athwart said endless channel so that the side edges of said barrier sealably engage opposed partitions and said bottom edge sealably engages the floor of said reactor basin, whereby said barrier divides said endless channel into an intake channel portion and a discharge channel portion;
- and
- (d) operating said axial-flow pump and said aeration means so that mixed liquor enters said discharge duct from said intake channel in substantially anoxic condition and is discharged into said discharge channel as freshly aerated mixed liquor which is thereafter circulated through said endless channel, from said discharge channel portion to said intake channel portion, returning to said barriered circulator/aerator upstream thereof.
Dependencies are inferred from the claim text.