Societe Degremont

Degremont, Societe Generale D'epuration Et D'assainissement

Jacques Bernard

Jean Durot

Michel Renaudin

A horizontal-axis aerator for use in a waste water purification system includes a cylinder having a horizontal axis, a first series of parallel blades on the surface of the cylinder and extending in directions nonparallel to the axis, and a second series of parallel blades on the surface of the cylinder and extending in directions nonparallel to the axis. The directions of the first series of blades are opposite to the directions of the second series of blades, with respect to the axis. The first and second series of blades intersect each other, such that upon the aerator being partially immersed in a body of waste water to be treated and being rotated therein, at any rotational position of the aerator about the axis, a constant portion of the total blade length of all of the blades of the aerator will be immersed in the waste water.

Horizontal-axis aerator for purification of waste water

A plant for the biological processing by means of activated sludge, by oxidation with pure oxygen or oxygen-enriched air, followed by a settling step, of a liquid suspension containing oxidizable matters, includes, in addition to the settling tank, a plurality of oxidation tanks disposed in series, communicating with each other, and adapted to be supplied with oxygen or oxygen-enriched air and the suspension to be treated, while recycling the decanted sludge, the suspension to be treated flowing in the direction of from the upstream tank to the downstream tank. The oxygen or oxygen-enriched air is introduced into the downstream tank and the venting of the plant to the atmosphere takes place from the upstream tank, whereby the venting of the plant to the atmosphere is responsive to the oxygen content of the gaseous phase in the upstream tank where the oxygen demand and therefore the oxygen concentration have their highest values, and the flow of oxygen or oxygen enriched air from the downstream tank wherein the demand for this gas and the consumption thereof are appreciably lower, cause an immediate and continuous increment in the oxygen content of the gaseous phase in the upstream tank, thus ensuring a rapid response to any oxygen demand together with a regular and continuous oxygen supply to the plant.

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St-Germain-en-Laye, France

Jacques Bernard