The anaerobic clarigester is a form of anaerobic digester. It is regarded as being the ancestor of the UASB anaerobic digester. A clarigester treats dilute biodegradable feedstocks and separates out solid and hydraulic (liquid) retention times. A diagram comparing the UASB, anaerobic clarigester and anaerobic contact processes can be found here.
References
Anaerobic clarigester Wikipedia(Text) CC BY-SA