Betaine removal during thermo- and mesophilic aerobic batch biodegradation of beet molasses vinasse: Influence of temperature and pH on the progress and efficiency of the process

The key issue in achieving a high extent of biodegradation of beet molasses vinasse is to establish the conditions for the assimilation of betaine, which is the main pollutant in this high-strength industrial effluent. In the present study, aerobic batch biodegradation was conducted over the temperature range of 27-63 degrees C (step 9 degrees C), at a pH of 6.5 and 8.0, using a mixed culture of bacteria of the genus Bacillus. Betaine was assimilated at 27-54 degrees C and the pH of 8.0, as well as at 27-45 degrees C and the pH of 6.5. The processes where betaine was assimilated produced a high BOD5 removal, which exceeded 99.40% over the temperature range of 27-45 degrees C at the pH of 8.0, as well as at 27 degrees C and the pH of 6.5. Maximal COD removal (88.73%) was attained at 36 degrees C and the pH of 6.5. The results indicate that the process can be applied on an industrial scale as the first step in the treatment of beet molasses vinasse. (C) 2011 Elsevier Ltd. All rights reserved.