Long vertical shaft bioreactor of simplified design

Claim 1

An improved long vertical shaft bioreactor comprising an enclosed head tank, a long vertical downcomer chamber, a long vertical riser chamber, the said downcomer and riser chambers operatively communicating with each other directly at their lower ends and through the said head tank at their upper ends thus forming a circulatory loop, both the said downcomer chamber and the said riser chamber having means for the injection therein at depth of an oxygen-containing gas, a waste influent conduit operatively opening into said riser chamber at a location above the location of the means for injecting oxygen-containing gas into said riser chamber, a waste effluent conduit operatively discharging from said riser chamber at a location below the location of the means for injecting oxygen-containing gas into said riser chamber, the improvement comprising a foam oxidation vessel surrounding the said head tank in such a manner that the said head tank is immersed in liquid in the foam oxidation vessel, the said head tank and foam oxidation vessel having first and second conduit means therebetween, said first conduit means comprising an inverted J configuration with the short arm of J discharging from the head tank at a position above the normal liquid level in the said head tank, the said second conduit means comprising an inverted J configuration with the long arm of the J discharging from the head tank at a position below the normal liquid level in the said head tank, the said first conduit means being adapted to transfer foam from the surface of the said head tank to the liquid in the said foam oxidation vessel, the said second conduit means being adapted to compensate for increased pressure in the said head tank caused by surges of influent discharge into the said bioreactor.