| 摘要 |
Disclosed is a nutrient recovery system and method for producing ammonium based fertiliser by heating and aerating anaerobic digester effluent made from waste fibrous material using a range of temperatures, aeration rates, aeration times. pH ranges, and settling times. The method includes heating and aerating anaerobic digester effluent in an aeration reactor for a time period ranging from 12 hours to 36 hours to convert soluble ammonium to gaseous ammonia. Gaseous ammonia is provided from the aeration reactor to a stripping tower, the stripping tower providing controlled amounts of acid that reacts with the gaseous ammonia; and recovering an ammonium salt produced from reacting the acid with gaseous ammonia in the stripping tower. Heating the anaerobic digester effluent to a temperature from about 140°F to about170°F comprises using a heat exchanger with the exhaust from a biogas engine generator gen set as the heated air stream. Aerating the anaerobic digester effluent is accomplished using micro-aerators that aerate the effluent at a rate from 5 gallons/cfm to 25 gallons/cfm. |
