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Abstract: In an effort to reduce the costs of drying pressed beet pulp, particularly high dry solids values are achieved in pulp pressing if, along with technological steps to achieve good pressing, marked bacterial activity occurs in the diffusion system. Since, with continuing uncontrolled infections microbial sugar losses are high and uncontollable, an attemt was made to optimize pulp pressing by "natural acidification" through continuous formalin dosing via a newly developed metering system which provides good distribution of the formalin in tower diffusers. The level of energy consumption for pulp drying (a function of the disinfection conditions) was compared with the costs associated with the controlled infection. Assuming that the total metabolic activity of the bacteria depends on sugar degradation, calculation of the costs for two Austrian sugar factories gave two different results. Whereas, in one case, an adjusted balance between sugar loss and improvement in drying costs occurred at a formalin dosage of 0.005 %, in the other sugar factory the costs of the sugar loss exceeded the energy saving in drying in all the selected variants. The reason for this could perhaps be found in the difference in bacterial populations between the two plants, which is also demonstrated by the different degradation properties of monosaccharides. Further investigations are planned for the 1986 campaign.
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