Title:
Baling and Ensiling of Wet Straw as Combined Storage and Pretreatment for Anaerobic Digestion
Author(s):
Larsen, S.U., Ma, N., Nielsen, S.V., Hjort-Gregersen, K., Møller, H.B.
Document(s):
Paper
Slide presentation
Abstract:
Straw is a very large resource of residual biomass with potential use in biogas production, however, it needs pre-treatment for more efficient utilization and higher biochemical methane potential (BMP). The aim of this study was to examine the potential of ensiling of wet cereal straw as a combined storage and pretreatment method for anaerobic digestion. Lab-scale ensiling of wheat straw and barley straw for 0 to 10 months with various water contents, ensiling additives and particle sizes showed increases in BMP of up to 19%, 24% and 24% after 3, 6 and 10 months of ensiling, respectively, for wheat straw and up to 28% after 6 months ensiling for barley straw. The increase in methane yield was primarily related to high water content during ensiling. Hence, when increasing the water content in wheat straw from 10 to 50%, BMP was increased linearly with up to 9% and 17% after 3 and 6 months of ensiling, respectively. After 10 months, BMP increased up to 16% with highest increase at water contents of 16%. In general, ensiling additives provided no extra increase in BMP compared to ensiling with 30% water and no additive. Pilot-scale ensiling of straw was performed with baling of wet straw with or without ensiling additives and with wrapping of individual bales which were ensiled for 4-8 months. Storage of wet straw with poor wrapping or no wrapping resulted in considerable heat generation and loss in dry matter and BMP. The pilot-scale trials confirmed that high water content is a key factor for reducing pH and increasing BMP during ensiling of straw. Ensiling has the potential to increase the BMP during storage of wet straw, however, the concept needs further development for practical implementation.
Keywords:
biogas, storage, straw, additives, pretreatment, ensiling
Topic:
Sustainable Resources for Decarbonising the Economy
Subtopic:
Agroforestry residues and by-products
Event:
31st European Biomass Conference and Exhibition
Session:
1CO.1.1
Pages:
74 - 79
ISBN:
978-88-89407-23-3
Paper DOI:
10.5071/31stEUBCE2023-1CO.1.1
Price:
FREE
