Removal of ammonia from fermentation effluent and sequestration as ammonium bicarbonate and/or carbonate

摘要

A method for the removal and sequestration of ammonia nitrogen from anaerobic fermentation effluent while producing a higher BTU biogas. The method includes the steps of removing the slurry from the digester, stripping the ammonia from the slurry or portion thereof with a high BTU biogas, blending the stripped ammonia with the digesters biogas to remove the carbon dioxide and precipitate ammonium bicarbonate/carbonate as a solid while producing a high Btu biogas, a portion of which is used to strip the ammonia and CO₂ from the slurry. The process removes ammonia nitrogen from the digester effluent while producing a high Btu biogas and a solid ammonium bicarbonate/carbonate product. Ammonia stripping is accomplished with a recycled stripping gas deficient in CO₂ and ammonia that is capable of removing the CO₂ and ammonia from solution by virtue of the lower partial pressures of CO₂ and ammonia in the stripping unit.