OWS has also developed the BES-Plugflow digestion technology. It is a horizontal plug-flow digester constructed in concrete. Although working at a lower total solids-content than the DRANCO-FARM technology, the DRANCO principle (first-in, first out) and OWS standards can be found in this technology.
The BES-Plugflow technology is a cross-over between the DRANCO-FARM technology and a conventional continuously stirred tank-reactor.
- horizontal digester in concrete
- total solids content between 5 and 15% in the digester
- plug-flow digestion (first-in, first-out)
- mesophilic or thermophilic operating temperature
- intensive recirculation (~ DRANCO-FARM)
- slow turning paddle stirrers
- modular concept
The BES-Plugflow process has some significant advantages:
- minimal retention time for semi-solid feedstocks
- optimal degassing inside the digester
- optimal heat- and material distribution inside the digester
- low electricity consumption
- limited height (< 11m)
- short construction period