The effect of packing density on the startup and operation of an anaerobic single stage fixed wheat straw bed digester

• In Southern Sweden, production of renewable energy from crop residues digestion is viewed as a worthwhile alternative. Also, the process gives valuable mineralised nitrogen as a by-product, which when produced at farm-scale can be recycled for ecological farming. It is difficult to achieve economic utilisation of crop residues in centralised slurry digestion, mainly because of the greater transport costs. Traditional reactor designs have a too low cost efficiency on farm-scale level, and therefore it is essential to introduce technologies and practices leading to economically viable reactor systems on this scale. One very simple reactor design being considered is the vertical column fixed bed digester. This allows relatively high loading rates, combined with a low maintenance requirement. Plant material can be used as a biofilm carrier, and is an inexpensive and highly efficient alternative to traditional support materials, and wheat straw, with its rigid structure and low biodegradability, is a good candidate. In this study, the influence of packing density on startup and single stage semi-batch operation of vertical column fixed bed digesters was examined in one laboratory-scale and three pilot-scale systems.

Subject headings

TEKNIK OCH TEKNOLOGIER  -- Industriell bioteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Industrial Biotechnology (hsv//eng)

Keyword

startup

straw digestion

fixed bed

crop residues

anaerobic filter

high-solids

packing density

Publication and Content Type

kon (subject category)

vet (subject category)