Degussa Aktiengesellschaft

Evonik Degussa Gmbh

Katayama Chemical, Inc.

Egon Walzer

Norbert Steiner

Roland Schneider

Andreas Reinold

Frank Dieter Kuhn

R&uuml;diger Peldszus

Michael Del Grosso

Martin Bauer

Walter Adami

Hubert Angert

Bernhard König

Steffen Krück

Corinna Schmidt

Martin Lietzenmayer

Method for reducing harmful organisms on surfaces in contact with continuously or periodically flowing currents of cooling water used for throughflow cooling without recirculation, wherein the harmful organisms are algae, mussels and slime forming organisms, by periodically adding an aqueous treatment agent containing at least one peroxycarboxylic acid with 1 to 6 C atoms to the flowing water once every 5 to 100 hours over a period of 3 to 60 minutes in an amount corresponding to at least 1 ppm of peroxycarboxylic acid to reduce growth of the organisms on the surfaces.

Method for reducing harmful organisms in currents of water

A method for preserving wood that includes impregnating the wood with a wood preservative agent based on one or more compounds of at least one metal of the 1 and/or 2 subgroups of the periodic system and fixing the metal(s) for purposes of reducing the danger of leaching. The wood is (i) impregnated with a preservative containing a water-soluble zinc compound or (ii) wood that has already been impregnated with a zinc-free preservative or one that contains at least one metal compound of the 1 and/or 2 subgroups is impregnated with a second preservative that contains at least one water-soluble zinc compound, and wood impregnated in accordance with (i) or (ii) is impregnated with an aqueous solution of a salt of trimercapto-s-triazine (TMT), dithiocarbamate or trithiocarbonate.

Method for preserving wood and preserved wood obtained in accordance with the method

Hardness-stabilizing and scale-preventing aqueous percarboxylic acid solutions contain a hardness stabilizer selected from the group (i) polymers prepared by oxidative polymerization of acrolein or of acrolein and acrylic acid, (ii) polyacrylic acid, (iii) copolymers of acrylic acid and another unsaturated carboxylic acid and (iv) polymaleic acid, wherein the average molecular weight M,of the hardness stabilizer is in the range 500 to 25000, and the solutions are obtained by adding the hardness stabilizer to a percarboxylic acid solution. Preferred solutions contain a hardness stabilizer (i) with a M,of 1000 to 15000. The solutions may also contain a surfactant. The solution can be used for controlling microorganisms in aqueous systems, in particular water-circulating systems.

Hardness-stabilizing percarboxylic acid solutions, a process for their preparation and their use

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Maintal, Germany

Egon Walzer