Aerobic biodegradation of potato slops under moderate thermophilic conditions: Effect of pollution load

The effect of the pollutant load on the efficiency of aerobic biodegradation of potato slops with a mixed population of thermo- and mesophilic bacteria of the genus Bacillus was examined. Batch biodegradation processes were carried out at 45 °C, using slops with the initial chemical oxygen demand (COD) totalling 11.3, 18.0, 42.6, 58.0 and 74.0 g O2/l. The extent of COD removal ranged from 80.4% (with COD of 11.3 g O2/l) to 88.7% (with COD of 58.0 g O2/l). With potato slops of higher initial COD levels (58.0 and 74.0 g O2/l), the first 24 h of growth were characterised by a deficiency of oxygen and a considerable rise in the content of acetic acid, which was then removed. In the first 48 h of the process, irrespective of the initial COD level, the biodegradation of the pollutants removed in the course of the entire process exceeded 91%. The rate of COD removal calculated for that period was a linearly increasing function of the initial pollution load.