Abstract: The invention relates to a method for purifying water and for dewatering sludge, comprising the following steps: bringing a surface-treated natural calcium carbonate, a natural bentonite and an anionic polymer into contact with the water or sludge, flakes being formed as a result of the agglomeration of particulate materials contained in said water or sludge, and separating said formed flakes so as to obtain purified water, or separating water in order to obtain dewatered sludge. The surface-treated natural calcium carbonate is a product of a reaction of natural calcium carbonate with an acid and carbon dioxide, which is formed in situ by the acid treatment and/or is fed from outside, and is produced as an aqueous suspension with a pH greater than 6.0 measured at 20° C. The invention also relates to a composition comprising said surface-treated natural calcium carbonate, a natural bentonite, and an anionic polymer, for the purpose of purifying water or dewatering sludge.

Abstract: The invention relates to a method for purifying wastewater loaded with nitrogen-containing compounds, wherein the wastewater loaded with nitrogen-containing compounds is reacted with a smectic sheet silicate, wherein a clay material loaded with nitrogen-containing compounds is obtained, and the clay material loaded with nitrogen-containing compounds is separated off, wherein purified wastewater is obtained.

Abstract: The invention relates to a method for purifying wastewater loaded with nitrogen-containing compounds, wherein the wastewater loaded with nitrogen-containing compounds is reacted with a smectic sheet silicate, wherein a clay material loaded with nitrogen-containing compounds is obtained, and the clay material loaded with nitrogen-containing compounds is separated off, wherein purified wastewater is obtained.