Continuous Stirred-Tank Reactor (CSTR) Anaerobic Digester

The CSTR is a completely-mixed form of anaerobic reactor, designed to maximize the contact between the biomass and the waste, to optimize digestion performance. One of the oldest digester configurations, it is also one of the best in terms of applicability to different wastes. No waste is too strong to employ the technology and with two different operating modes and many different forms of biogas retention, the CSTR is an extremely flexible process.

The wastewater (wastewater/sludge mixture) enters the reactor at the bottom and leaves at the top and includes an internal recycle loop which draws reactor contents from the opposite side of the entry. Proper mixing by means of a top-entry, multi-stage agitator ensures that the influent is in constant contact with the biomass for optimal mass transfer and conversion of organic content (COD) to biogas. Depending on the application besides the top entry mixers, other solutions can be applied, such as side mixers or jet mixers.