Vertical looped reactor tank with delayed air release feature

Claim 1

In an activated sludge wastewater treatment apparatus comprising: an elongated confining means having end walls comprised of a sewage inlet end and a sewage outflow end, side walls, and an interior chamber capable of containing a given liquid level; horizontally disposed gas-impermeable first baffle means substantially coextensive with said confining means, yet spaced apart from the end walls thereof to provide flow passages between said baffle means and end walls; said first baffle means being positioned within said interior chamber below said liquid level; said confining means and said first baffle means defining a plurality of serially interconnecting passageways that establish an elongated endless vertical flow circuit for providing complete mixing of sewage matter within said confining means; means applying raw sewage and recycled sludge to said interior chamber, said recycled sludge supplying a population of microscopic biota to said circulating liquid in said chamber; an aeration means positioned in at least one of said passageways for introducing air and flow-inducing energy to sewage matter within said interior chamber; and means for removing treated sewage from said interior chamber; wherein the improvement comprises at least one secondary horizontally-disposed, gas permeable baffle means substantially coextensive with said side walls of said confining means and constructed and arranged near said sewage inlet end between said first baffle means and the surface of said liquid in said confining means to capture air bubbles retained by said first baffle means, and delay the escape of said bubbles to said surface of said liquid by fragmenting said bubbles to increase their absorption into the liquid and eventual metabolism by said circulating biota.