Aqueous Ammonia Soaking of Wheat Straw at Ambient Temperature for Enhancing the Methane Yield: Process Optimization by Response Surface Methodology

• Published in: Waste and biomass valorization 2020-09, Vol.11 (9), p.4821-4835
• Main Authors: Lymperatou, Anna, Gavala, Hariklia N., Skiadas, Ioannis V.
• Format: Article
• Language: English
• Subjects: Ambient temperature; Ammonia; Anaerobic conditions; Anaerobic digestion; Engineering; Environment; Environmental Engineering/Biotechnology; Hemicellulose; Industrial Pollution Prevention; Lignin; Methane; Optimization; Original Paper; Reagents; Renewable and Green Energy; Response surface methodology; Solubilization; Straw; Strong interactions (field theory); Waste Management/Waste Technology; Wheat; Wheat straw
• ISSN: 1877-2641; 1877-265X
• DOI: 10.1007/s12649-019-00806-7

Aqueous ammonia soaking (AAS) at ambient temperature was applied to wheat straw under different conditions in order to maximize the CH 4 yield through mesophilic anaerobic digestion. The effects of the NH 3 concentration, duration of AAS and solid-to-liquid ratio were studied on the resulting CH 4 yield and the solubilization degree of the pretreated wheat straw. A strong interaction among the NH 3 concentration and the duration of AAS was observed. The optimal conditions found were 18% w/w NH 3 , 7 days of duration and 50 g straw/L reagent, leading to a 43% increase of the CH 4 yield in 17 days of digestion. Compositional analysis of the optimally-treated wheat straw revealed that a significant solubilization of hemicellulose took place during AAS together with a moderate lignin removal (9%). Graphic Abstract