Organics and nutrient recovery from anaerobic digester residues

摘要

Sludge from an anaerobic digester is treated to recover one or more of fibers, or solids or liquids with a high nutrient content. The solids or liquids can be used as a fertilizer. The fibers can be used in a plant growing medium. Solids are separated from liquids in the sludge and dried. The solids may be dried to produce a flake or pellet. Ammonia in the liquids is recovered and used to produce a concentrated acidic ammonium salt solution. This solution may be mixed with the solids to produce a nitrogen enhanced solid. The fibers and solids or liquids can also be used in combination to produce an enhanced plant growing medium. A device and process for removing ammonia from a liquid can be used in the system or separately.

主权项

1. A process for treating a sludge, the sludge comprising solids and ammonia, the process comprising the steps of,
(a) separating sludge produced in an anaerobic digester into a solids fraction and a liquid fraction, the liquid fraction comprising ammonia; (b) treating the liquid fraction to produce an ammonium salt solution; and, (c) combining the solids fraction with the ammonium salt solution, and further comprising a step of decarbonatinq the liquid fraction.