Unschädlichmachung der Abwässer durch bessere Ausnutzung des Rohstoffes bei der Kartoffelstärkeerzeugung

Abstract Neutralization of Waste Waters by Better Exploitation of Raw Material During Production of Potato Starch . Neutralization of fruit juice set free during the production of potato starch can be carried out efficiently in two steps. The first step is based upon the coagulation of protein at 85 °C in acidify medium. The first step of methane fermentation, which is the acid fermentation, is made use of for this process. At this step mainly heterogeneous lactic acid fermentation takes place. Coagulated protein may be efficiently processed into feed thus making the purification of waste water more profitable. The second step is the methane fermentation as such. Considering the concentration of fruit juice from the separators a maximum load of the fermentation tank of 1.5 kg/m 3 of organic matter has to be taken in account. At a higher load the period of fermentation is shortened to an extent that makes anaerobic processes impossible. During fermentation 15.25 m 3 of fermentation gas per m 3 raw water with a methane content of 54% are produced. This amount of gas should be sufficient for heating of the waste water up to a temperature which is necessary for caogulation. The fermentation of fruit juice has to be succeeded by a one‐hour period of sedimentation of the mud. Thus, purification is made more effective. With this system the concentration of the fruit juice decreases to an extent which makes it possible to purify it further together with the processing water in a biological activation filter plant.