Patent ID: 7520990

Claim:
An anaerobic wastewater treatment system, comprising: (a) a recycle tank including an intake for receiving wastewater, a recycle inlet for receiving recycled water and an outlet for discharging a recycle mixture including recycled water and wastewater, (b) a bioreactor tank having an intake near its lower end, an overflow outlet toward its upper end and a biogas vent at its extreme upper end, the intake of the bioreactor tank connected with the recycle tank outlet for receiving the recycle mixture from the recycle tank, the bioreactor tank containing a fluidized bed including a multitude of anaerobic bacteria microbial consortia particles adapted for digesting waste and producing biogasses including methane and carbon dioxide, the bioreactor tank overflow outlet for overflowing escape of the bioreactor tank suspension including entrained microbial consortia particles and treated water mostly free of waste, the bioreactor tank further including gas disengagement portion proximate to the overflow outlet for mechanically separating gas bubbles from said microbial consortia particles prior to passage of the treated water and the entrained microbial consortia particles through the overflow outlet, (c) a bioselector having an intake with a tangent intake geometry in communication with the overflow outlet of the bioreactor tank for receiving bioreactor tank suspension including the treated water and microbial consortia particles from the bioreactor, the bioselector also having a generally circular cross section and a cone shaped lower end, the tangent intake geometry of the bioselector intake causing the treated water to swirl within the bioselector such that suspended microbial consortia particles move toward the walls of the bioselector, the microbial consortia particles subsequently sinking to the bottom of the bioselector for collection and return via the return outlet to the intake of the bioreactor, the bioselector also having a recycle outlet in communication with the recycle tank for passage of a recycle portion of the treated water to the recycle tank and an overflow outlet for releasing an effluent portion of the treated wastewater as treated effluent leaving the system.