Abstract: An apparatus for continuously producing alcohol by fermenting a mash containing starch, sugar, and similar carbohydrates includes a series of main fermentation vessels and an auxiliary fermentation vessel. The mash, in mixture with yeast, is transferred in succession through the main vessels during normal operation of the apparatus. When the main fermentation vessels are to be cleaned, the further flow of the mash is diverted into the auxiliary fermentation vessel for a period of time sufficient to empty and clean the first main fermentation vessel in the series, whereupon the supply of the mash to the first main fermentation vessel is restored. The gap in the mash supply propagates through the series of the main fermentation vessels so that the remaining vessels can be in turn cleaned as well.

Abstract: A method for the submersed, automatically controlled production of fermentation vinegar from ethanol is conducted in two stages. The installation for accomplishing the method includes one or more pre-fermenters and a product fermenter, in connection with which each pre-fermenter exhibits a volume 1.7 to 3.5 times that of the product fermenter. The terminus of the fermentation is reached in the product fermenter when the dissolved oxygen, indicated by means of an oxygen electrode, rises, at which point the product valve is opened. The product fermenter is evacuated when no more alcohol remainder is present. In the final step the alcohol is therefore completely utilized.

Abstract: An apparatus is provided for the multistage biological purification of waste water containing organic substances including carbohydrates and proteins. The apparatus comprises an at least substantially closed first tank for holding waste water while maintaining the waste water at least substantially free from contact with air so as to prevent further oxygen from becoming dissolved in the waster water. The apparatus also includes a second tank including an aerator for dissolving oxygen in waste water contained in the said tank, the second tank being located inside the first tank and including a conical bottom portion for receiving sludge produced by aerobic degradation of the waste water in the second tank.