Measures against water pollution in beet sugar processing industries

Abstract

In an introduction to the process the three principal steps are first mentioned: preparation of juice by extraction, purifying this juice and crystallizing sugar from the purified juice. A more complete flow sheet is then given, considering water use and re-use and effluent production in every step. A completely open factory would produce between 100000 and 200000 population equivalents per 1000 metric tons daily capacity. After the introduction of modern continuous extraction equipment, the recirculation of the hot water from the jet condensers and the elimination of all spill and overflow, the only remaining inevitable source of pollution is the loss of juice from wounded beets in the transport- and wash-waters. This loss is directly proportional to the injured beet surface. Undamaged beets would cause a loss of 0.025% sugar, and a pollution of 2500 population equivalents (1–2% of an open factory). Mechanization of beet harvest and transport, however, caused a rise in sugar losses to about 0.2 % of the beet weight. At this level of injury practically no part of the beet surface remains undamaged. When we want to diminish pollution, a programme to minimize beet injury deserves priority. A reduction of sugar losses by 0.1%, relative to the Dutch beet harvest, can be assessed at [formula omitted] million guilders per annum in the form of export sugar, apart from a pollution abatement of 600000 population equivalents. A further decrease of pollution can be realized by lagooning and biological purification, the economic optimum depending on local conditions. © 1972, Walter de Gruyter. All rights reserved.