Biofilter for removal of nitrogen oxides from contaminated gases under aerobic conditions
AssigneeLockheed Martin Idaho Technologies Company
InventorWilliam A. Apel
Life of this patent
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Abstract
A biofilter for reducing concentrations of gaseous nitrogen oxides in a polluted gas comprises a porous organic filter bed medium disposed in a housing, the filter bed medium including a mixed culture of naturally occurring denitrifying bacteria for converting the nitrogen oxides to nitrogen gas, carbon dioxide, and water. A method of reducing concentrations of nitrogen oxides in polluted gas comprises conducting the polluted gas through the biofilter so that the denitrifying bacteria can degrade the nitrogen oxides. A preferred filter medium is wood compost, however composts of other organic materials are functional. Regulation of pH, moisture content, exogenous carbon sources, and temperature are described.
Claims31
A method of producing a denitrified gas from a gas stream containing nitrogen oxides and optionally up to about 5% oxygen, comprising the steps of:
- (a) providing a biofilter comprising
- a housing comprising an inlet couplable to gas conducting means for receiving the nitrogen oxide-containing gas stream into the biofilter from said gas conducting means and an outlet for removing the denitrified gas out of the biofilter;
- a porous organic filter bed medium disposed in the housing, the bed medium comprising a naturally occurring mixed culture of denitrifying bacteria capable of converting the nitrogen oxides under aerobic conditions to nitrogen gas, carbon dioxide, and water;
- (b) receiving the nitrogen oxide-containing gas stream into the biofilter through the inlet so that the gas stream passes through the bed medium wherein the denitrifying bacteria convert the nitrogen oxides under aerobic conditions to nitrogen gas, carbon dioxide, and water thereby producing a denitrified gas;
- and
- (c) removing the denitrified gas out of the biofilter through the outlet.
A biofilter for producing a denitrified gas from a gas stream containing nitrogen oxides and optionally up to about 5% oxygen, comprising
- a housing comprising an inlet couplable to gas conducting means for receiving the nitrogen oxide-containing gas stream into the biofilter from said gas conducting means and an outlet for removing the denitrified gas out of the biofilter;
- and
- a porous organic filter bed medium disposed in the housing so that the nitrogen oxide-containing gas stream passes through the filter bed medium for denitrification, the filter bed medium comprising a naturally occurring mixed culture of denitrifying bacteria for converting the nitrogen oxides under aerobic conditions to nitrogen gas, carbon dioxide, and water.
Dependencies are inferred from the claim text.