Open AccessAmmonia ( NH 3 ) emissions during drying of untreated and dewatered biogas digestate in a hybrid waste‐heat/solar dryer
Author(s) -
Maurer Claudia,
Müller Joachim
Publication year - 2012
Publication title -
engineering in life sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.547
H-Index - 57
eISSN - 1618-2863
pISSN - 1618-0240
DOI - 10.1002/elsc.201100113
Subject(s) - digestate , biogas , environmental science , pulp and paper industry , waste management , solar dryer , anaerobic digestion , ammonia , renewable energy , water content , environmental engineering , chemistry , methane , engineering , electrical engineering , organic chemistry , geotechnical engineering
Digestate from the biogas digestion process contains high amounts of water and nitrogen, which can lead to over‐fertilization problems in regions with intensive livestock farming due to a surplus of ammonium, which contributes to the global warming effects. The best option to reduce the water content as well as to concentrate the nitrogen is to dry digestate; however, volatile nitrogen present in the digestate has the tendency to be emitted. Therefore, the objective of this study was to investigate the emissions of untreated and dewatered digestate during the drying process and to determine the nitrogen loss of the drying product by calculating the loss over time by the emissions and compare it with initial and final ammonium content made by chemical analysis. The drying procedure was performed in a hybrid waste‐heat/solar dryer. Ammonia rate was measured continuously during drying by Fourier transform infrared spectroscopy. Untreated digestate showed higher cumulative emissions of ammonia ( 25 . 9g NH 3kg DM− 1) than dewatered material ( 7 . 75g NH 3kg DM− 1) due to lower water content and shorter drying time. Emissions from the filtrate may still be an issue, which should be addressed in future studies.