Method for anaerobic sludge digestion and digester
AssigneeErgalia
InventorsPhilip Herve, Maunoir Siegfried
Life of this patent
Estimating the term…
Abstract
A method is provided for introducing a fresh sludge flux whose concentration in terms of dry material is less than 40 g/l into the upstream part of digester, maintaining a thin sludge layer in the digester, circulating substantially horizontally effluents above and across the sludge layer and removing the effluents from the digester simultaneously with soluble products of sludge digestion. The cuvette of the digester is divided into sections by transverse walls, which are provided with communication openings in the lower part thereof.
Claims25
A method for anaerobic digestion of sludge resulting from the treatment of sewage effluents, comprising the steps of:
- inserting a flow of primary sludge in the upstream part of an anaerobic sludge digester, said primary sludge containing effluents and having a dry matter concentration of less than 40 g/l;
- maintaining a layer of sludge in the digester with a thickness of less than 0.6 m, the sludge being transformed by anaerobic digestion;
- circulating the effluents within the digester, above and through the layer of sludge, in a substantially horizontal direction, from the upstream part towards the downstream part of the digester;
- draining off the effluents from the digester, so as to drain off the soluble products of sludge digested from the digester;
- and
- draining off the sludge from the digester.
An anaerobic sludge digester, comprising:
- a tank having a substantially horizontal bottom;
- a first pipe connected to the tank that feeds the tank with primary sludge;
- a second pipe connected to the tank that draws off effluents from the tank;
- and
- a wall transverse to the flow of the effluents,
- wherein the wall defines an upstream compartment and a downstream compartment, such that the tank has a first upstream compartment into which the primary sludge feeding pipe flows, and a downstream compartment from which the effluent discharge pipe flows, and
- wherein the wall has proximate a bottom an opening that connects the upstream compartment with the downstream compartment, so as to enable the passage of the sludge and the circulation of the effluents, above and through the layer of sludge maintained on the bottom of the tank, in a substantially horizontal direction from the first upstream compartment to the downstream compartment.
A treatment plant for sewage effluents, comprising
- a primary settling tank adapted to be supplied with sewage effluents and discharge primary sludge and settled effluents;
- and
- a digester connected to the primary settling tank adapted to receive primary sludge from the primary settling tank, wherein the digester comprises
- a tank having a substantially horizontal bottom;
- a first pipe connected to the digester tank that feeds the digester tank with primary sludge from the primary settling tank;
- a second pipe connected to the digester tank that draws off effluents from the digester tank;
- and
- a wall transverse to the flow of the effluents,
- wherein the wall defines an upstream compartment and a downstream compartment, such that the digester tank has a first upstream compartment into which the primary sludge feeding pipe flows, and a downstream compartment from which the effluent discharge pipe flows, and
- wherein the wall has proximate a bottom an opening that connects the upstream compartment with the downstream compartment, so as to enable the passage of the sludge and the circulation of the effluents, above and through the layer of sludge maintained on the bottom of the digester tank, in a substantially horizontal direction from the first upstream compartment to the downstream compartment.
Dependencies are inferred from the claim text.