US Patent 7520990 Anaerobic wastewater treatment system and method

An anaerobic wastewater treatment system includes a recycle tank, a bioreactor tank and a bioselector for recapturing anaerobic microbial consortia particles escaping from the bioreactor tank and returning them to the bioreactor tank. The bioreactor tank receives recycled wastewater feed from a recycle tank and discharges via an overflow outlet treated wastewater and microbial consortia particles to a bioselector. The bioselector is adapted to separate entrained microbial consortia particles and return a feed to the bioreactor tank which including some of the treated wastewater received from the bioreactor tank and the microbial consortia particles received from the bioreactor tank. The bioselector provides a recycle feed to the recycle tank. Overflow from the bioselector provides an effluent of treated wastewater leaving the system.