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US 4,225,430 AGranted
Biological process
AssigneeAECI Limited
InventorJohanna Bosman
Life of this patent
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Abstract
A process for denitrifying a highly nitrogenous wastewater in the presence of high concentrations of ammonia is described. The process is based on upflow packed bed and fluidized bed reactors containing denitrifiers on the packing material. A carbon source, e.g. molasses, is metered into the wastewater as a source of carbon and energy to the bacteria. Excess bacteria are removed by hydraulic shear.
Claims14
A method for denitrifying a high nitrogen content waste water effluent comprising
- (i) passing a feed of said waste water effluent through a packed bed reactor containing denitrifying bacteria which are heterotrophic and facultative anaerobes on the packing material to denitrify said waste water effluent
- wherein the feed has a pH of 6 to 7.5, a nitrate nitrogen concentration in excess of 1000 mg/l and ammonia nitrogen in excess of 1000 mg/l and is admixed with molasses, as a carbon source, in an amount sufficient to effect the denitrification of said waste water effluent;
- and
- (ii) simultaneously and continuously passing a recycle stream which is a substantially denitrified stream of the waste water feed of (i) through the bed, in a volume such that the volume ratio of recycle stream to feed ranges from 2 to 200
- wherein the volume and rate of recycle stream in (ii) are sufficient to effect a linear velocity of the combined feed and recycle stream through the bed ranging from 4 to 200 m.sup.3 /m.sup.2 hr,
- and to effect a hydraulic shear within the bed which continuously remove accumulated biomass which is in excess of that required to effect denitrification.
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Dependencies are inferred from the claim text.