Anaerobic biodegradability of gallic acid found in olive mill wastewaters

Abstract

AbstractThis paper discusses the applicability of a low‐cost method for evaluating the ability of anaerobic micro‐organisms to decompose phenolic compounds found in olive mill wastewaters. Gallic acid (GA) was used as test substance at concentrations of 100, 500 and 1000 mg L−1. When 1000 mg L−1 GA was inoculated with anaerobic sludge, the average (of six replicates) cumulative gas volume collected over a period of 23 days was 87.6 ± 2.4 mL, while without sludge the volume was 9.3 ± 1.0 mL. The corresponding values for 500 mg L−1 GA were 48.0 ± 8.0 and 6.5 ± 1.0 mL respectively, while for 100 mg L−1 GA they were 30.8 ± 4.7 and 9.6 ± 2.3 mL respectively. These results suggest that gallic acid is readily degradable under anaerobic conditions even at concentrations as high as 1000 mg L−1 if adequate fermentation time and appropriate microbial culture are provided. The gas volume produced was found to depend linearly (r2 = 0.95) on the concentration of gallic acid under the conditions studied. Copyright © 2006 Society of Chemical Industry