Thermal drying of the solid fraction from biogas digestate: Effects of acidification, temperature and ventilation on nitrogen content.
Drying of solids produced from digestate is prone to N losses through NH3 volatilisation. The applicability of acidification as an NH3 emission mitigation technique during the drying of solids from digestate was assessed in a drying experiment. Operating conditions comprised four drying temperatures (70-160°C), two air ventilation rates (natural, 420ml/min) and three pH levels (9.2, 6.5 and 5.5) of the solids, modified by the addition of concentrated sulphuric acid. Acidification of the solids from digestate significantly decreased the NH3 emission during drying, irrespective of the drying conditions. A parallel decrease in the organic nitrogen content and an increase in the ammonium content of the solids was observed after acidification of the solids. It was confirmed that acidification before thermal concentration of solids from digestate, minimised NH3 losses under a wide range of drying conditions.
Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg, Denmark.
Athanasios
A
Pantelopoulos
Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg, Denmark.
Jakob
J
Magid
Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg, Denmark. Electronic address: lsj@plen.ku.dk.
Lars Stoumann
LS
Jensen
D000641:Ammonia / Q000032:analysis; D056804:Biofuels; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D009584:Nitrogen / Q000032:analysis*; D012037:Refuse Disposal / Q000379:methods*; D062611:Solid Waste; D013696:Temperature
D056804:Biofuels; D062611:Solid Waste; D000641:Ammonia; D009584:Nitrogen
Ammonia; Drying method; Hydrolysis; Organic waste; pH