Enhancing performance in anaerobic high-solids stratified bed digesters by straw bed implementation

Summary, in English

Anaerobic high-solids single-stage stratified bed digesters have been found to be simple and flexible design candidates for small-scale reactors located in medium- to low-technology environments. In the present study, wheat straw was used as the starter material for the stratified bed. Upon green mass feeding, the anaerobically stabilised straw bed functioned both as a biofilm support and as a particulate filter. It enabled a direct onset of 7 kg VS m(-3) batch loads, added twice a week, and permitted a low but consistent bed permeability during feeding at an average superficial flow velocity of 1 m d(-1) to be achieved. Fed-batch tests with sugar beet tops in pilot- and laboratory-scale setups at an average loading rate of 2 kg VS m(-3) d(-1) resulted in average biogas production rates of 1.2-1.4 m(3) m(-3) d(-1) and methane yields of 0.31-0.36 m(3) kg(-1) VSadded. At the end of the laboratory-scale feeding trial, the 200 day old straw bed had compacted to 50% of its initial volume, without any negative effects on performance being detectable. (c) 2005 Elsevier Ltd. All rights reserved.

• Author: Mattias Svensson; Lovisa Björnsson; Bo Mattiasson
• Department/s: Biotechnology; Environmental and Energy Systems Studies
• Publishing year: 2007
• Language: English
• Pages: 46-52
• Publication/Series: Bioresource Technology
• Volume: 98
• Issue: 1
• Links: http://dx.doi.org/10.1016/j.biortech.2005.11.023
• Document type: Journal article
• Publisher: Elsevier
• Topic: Industrial Biotechnology
• Keywords: lignocellulosics; fixed bed; farm-scale; dry digestion; packing density; crop residues; straw bed priming; foaming; intermittent leachate recycle
• Status: Published
• ISBN/ISSN/Other: ISSN: 1873-2976