METHOD FOR FREEZING COLLOIDAL SLUDGE-LIGNIN RESIDUES BY TRENCHING Russian patent published in 2020 - IPC C02F11/20 C02F103/28 

FIELD: waste processing and disposal.

SUBSTANCE: invention relates to processing of pulp and paper industry wastes in form of colloidal sludge-lignin residues by removal of colloid-bound water. Method includes natural freezing of sludge-lignin sediment in accumulation maps during cold season with subsequent thawing, accompanied by destruction of paste-like colloidal structure and transition into solid granular state. Method is implemented in accumulation maps by means of trenches laying on depth of packed sediment with width of 1 m along the whole length of maps with pitch of 2 m. Sediment extracted from tranches is stored on board between trenches.

EFFECT: method provides intensification of processes of destruction of colloidal structure of large-tonnage sediments of sludge-lignin due to considerable increase of total volume of useful surface of freezing of sediment, which leads to considerable reduction of precipitate moisture content.

1 cl, 1 tbl