Biogas Magazine | Edition 19 | 33
CSTR based semi dry fermentation of Organic Solid Feedstocks
J
&F biogas offers a semi dry fermentation process based on the CSTR (Continuous stirred tank reactor) for the conversion of feedstocks with high dry matter content to biogas. The technology has been in use for over 15 years, with close to 100 biogas plants operating primarily in Europe. Organic solid feedstocks such as paddy straw, press mud, poultry litter, bagasse, napier grass have dry matter between 20 % to 85%. CSTR semi dry fermentation process can be used for feedstock with up to 35% dry matter without addition of water.
This article discusses the possibility of converting sugarcane industry based feedstock’s such as press mud and bagasse to biogas using CSTRbased semi dry fermentation process. It is estimated that India alone could generate close to 441,000 tonnes of CBG per year by using press mud as a feedstock for biogas generation.
high Dry matter (DM). The process can handle organic waste up to 30-35% DM without additional water for dilution. A unique mixing system was developed for handling high viscosity inside the digester, typically associated with feedstock containing high dry matter.
In the context of sugarcane industry, press mud has 30% DM (Dry matter) and bagasse 1. CSTR semi-dry fermentahas 50% DM respectively tion process which can be digested using There are various types of CSTR Semi dry fermentation anaerobic digestion technol- process. ogies available for digestion of various organic feedstock. 2. Press mud Selecting the right technolIn comparison to other tech- ogy for a specific substrate is Filter cake, commonly known nologies, the CSTR semi-dry critical to the successful op- as press mud, is the suspendfermentation process re- eration of a biogas plants. J & ed impurities separated, quires half the size of digest- F Biogas has developed CSTR during the process of cane ers, has lower operating costs, based semi dry fermentation juice clarification by the suland generates very little or no process, which is specifically phitation process. Press mud liquid slurry in biogas plants. suited for organic waste with traditionally is used as ma-
