Abstract: A separation apparatus comprising, a series of compartments for holding particulate separation material, arranged so as to allow fluid to flow through the compartments in a primary direction from a first compartment in the series to a last compartment in the series, feed means for directing a flow of the fluid into the first of the series of compartments in the primary direction, barrier means for preventing flow of particulate separation material between compartments in the primary direction, and a pumping assembly arranged to pump a mixture of the particulate separation material and the fluid from the first compartment into a recovery stage.

Abstract: A separation apparatus comprising, a series of compartments for holding particulate separation material, arranged so as to allow fluid to flow through the compartments in a primary direction from a first compartment in the series to a last compartment in the series, feed means for directing a flow of the fluid into the first of the series of compartments in the primary direction, barrier means for preventing flow of particulate separation material between compartments in the primary direction, and a pumping assembly arranged to pump a mixture of the particulate separation material and the fluid from the first compartment into a recovery stage.

Abstract: A reactor for aerating a fluid with a gas comprises a mixing tank (12) for the fluid and a centrally located vertical draft tube (13) submerged in the fluid to divide the mixing tank (12) into an inner chamber (21) and an outer chamber (23). The reactor further comprises a motor driven axial flow impeller (14) located in the draft tube (13) for circulating fluid downwardly through the inner chamber (21) and upwardly through the outer chamber (23). The reactor further comprises an external circuit for withdrawing a portion of the fluid from the mixing tank (12), aerating the fluid, and returning the aerated fluid to the mixing tank (12). The aerator is in the form of a venturi device (17).

Abstract: A reactor for aerating a fluid with a gas comprises a mixing tank (12) for the fluid and a centrally located vertical draft tube (13) submerged in the fluid to divide the mixing tank (12) into an inner chamber (21) and an outer chamber (23). The reactor further comprises a motor driven axial flow impeller (14) located in the draft tube (13) for circulating fluid downwardly through the inner chamber (21) and upwardly through the outer chamber (23). The reactor further comprises an external circuit for withdrawing a portion of the fluid from the mixing tank (12), aerating the fluid, and returning the aerated fluid to the mixing tank (12). The aerator is in the form of a venturi device (17).

Abstract: A reactor for aerating a fluid with a gas comprises a mixing tank (12) for the fluid and a centrally located vertical draft tube (13) submerged in the fluid to divide the mixing tank (12) into an inner chamber (21) and an outer chamber (23). The reactor further comprises a motor driven axial flow impeller (14) located in the draft tube (13) for circulating fluid downwardly through the inner chamber (21) and upwardly through the outer chamber (23). The reactor further comprises an external circuit for withdrawing a portion of the fluid from the mixing tank (12), aerating the fluid, and returning the aerated fluid to the mixing tank (12). The aerator is in the form of a venturi device (17).