Abstract: The invention is directed to a method for the removal of mercury and selenium from sulfate-containing waste water. The method may include the following steps: a) a mercury- and selenium-contaminated waste water with a known sulfate concentration is provided, b) barium sulfate (BaSO4) is precipitated from the provided waste water by the addition of a predefined amount of Ba2+ ions to the waste water, c) BaSO4 (if necessary together with other solids) is separated obtaining a low-solid waste water, d) the low-solid waste water is fed to an ion exchanger for the removal of mercury obtaining a waste water with a reduced mercury content, e) selenium and/or selenium compounds are removed from the waste water with the reduced mercury content and f) a sulfate-containing solution or solid is added to the waste water with a reduced selenium and/or selenium compound content in order to precipitate barium sulfate.

Abstract: The method according to the invention provides a method for treating a waste water, where (a) the waste water is provided having specific sulfate, chloride, mercury, and selenium concentrations, (b) the waste water (WW) is fed to a high pressure separator 1 using a high-pressure pump (P1) in which the waste water (WW) is separated into a permeate volume (PV) containing reduced sulfate, chloride, mercury, and selenium concentrations and a concentrate volume (CV), (c) and where the concentrate volume (CV) is separated using a cleaning apparatus 4 that reduces both mercury and selenium in the concentrate volume.

Abstract: The invention is directed to a method for the removal of mercury and selenium from sulfate-containing waste water. The method may include the following steps: a) a mercury- and selenium-contaminated waste water with a known sulfate concentration is provided, b) barium sulfate (BaSO4) is precipitated from the provided waste water by the addition of a predefined amount of Ba2+ ions to the waste water, c) BaSO4 (if necessary together with other solids) is separated obtaining a low-solid waste water, d) the low-solid waste water is fed to an ion exchanger for the removal of mercury obtaining a waste water with a reduced mercury content, e) selenium and/or selenium compounds are removed from the waste water with the reduced mercury content and f) a sulfate-containing solution or solid is added to the waste water with a reduced selenium and/or selenium compound content in order to precipitate barium sulfate.