Technology Briefs

Anaerobic Plug Flow Reactors (APFR)
Plug flow digesters are long and narrow, with a tubular cross section along the length. These are usually concrete enclosures with a rigid or flexible cover. APFR is classified as a ‘low-rate’ system. Some other names used for APFRs are piston flow reactor, pipe flow reactor, and continuous tubular reactor.
CSTR is considered as the earliest high rate anaerobic digestion reactor. This first generation technology has demonstrated higher reliability. CSTRs are applied to treat wastewater having high-levels of suspended solids. This is widely used to treat high-strength liquid animal manure & solid substrates, & organic industrial wastes. This technology can be adopted to accommodate co-digestion, as well as to produce bio-hydrogen.
UASB reactor was developed in the 1970s by Lettinga and his team at the University for Agriculture at Wageningen, the Netherlands. This type of high rate biogas systems are preferred for the anaerobic treatment of industrial wastewater with high organic loading rates.
UAFF reactors are very similar to Anaerobic Filter reactors, where wastewater travels through a packed filter bed. The anaerobic filter is fed at a lower level and effluent exits at a higher level of the reactor. Unlike in anaerobic filters, instead of the packed filter bed, UAFF reactors have a Floating Bacteria Growing Media (BGM). Bacteria are attached on to the floating Bacteria Growing Media (BGM).