Bayer Aktiengesellschaft

Otto Barth

Guido Steffan

Horst Behre

Thomas Melin

Reinhard Kaiser

Jurgen Zander

Hans-Joachim Becker

Hubert Stracke

The outgoing gas or waste water is conveyed through a gas-liquid contact apparatus in which biological purification takes place. A bubble plate-type column (2) is used as gas-liquid contact apparatus. The biomass is distributed over the plates (3) in the form of an aqueous suspension with a layer height corresponding to a liquid content per plate greater than 0.07 m.sup.3 /m.sup.2, preferably greater than 0.15 m.sup.3 /m.sup.2 of column cross-section. During the biological purification of gas, the gas to be purified is supplied at the lower end of the bubble plate-type column (2). It then flows through the plates (3) and issues again as purified gas at the top of the plate column (2). When the plate column is used for purifying waste water, the waste water to be purified is conveyed from top to bottom through the plate column (2) and is traversed by air, oxygen or oxygen-containing gas. At the same time, a proportion of the biomass is separated from the purified waste water and re-circulated into the entering waste water or into the column. The waste water to be purified flows successively over the plates (3) to the liquid outlet (11). From here, the clarified waste water flows out through the overflow (13). This process is suitable, in particular, for highly charged waste water, particularly if a compact structure is required during construction of the apparatus.

Bubble plate system for biological purification of air and waste water

A process has been invented for the preparation of aminonaphthalenesulphonic acids by the catalytic hydrogenation of salts of nitronaphthalenesulphonic acids with hydrogen in the presence of Raney nickel catalysts at elevated temperature and pressure, said catalysts comprising a combination of fresh Raney nickel catalyst and Raney nickel catalyst which has already been used in prior hydrogenation or hydrogenations.

Process for the preparation of aminonaphthalenesulphonic acids

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Bergisch-Gladbach, Germany

Otto Barth