Absorption and Biodegradation of Toluene in a Two-Phase Low-Pressure Bioscrubber Using Cutting Oil as the Organic Phase

Abstract

Background: Volatile organic compounds are a major source of air pollution affecting human health and the environment. Different methods are used to remove these pollutants from air streams including conventional and biological methods. Objectives: In this study, the absorption and biodegradation of toluene were examined in a semi-industrial bioscrubber in order to enhance the absorption rate of toluene in the aqueous phase. Methods: The effect of cutting oil was examined as the organic phase. Mass transfer was measured for water only, as well as for three concentrations of cutting oil in water. The growth of microorganisms in the presence of different concentrations of cutting oil was investigated. The microbial consortium was obtained from a wastewater treatment plant in order to inoculate the bioscrubber. First, the ability of the microbial consortium was tested for the degradation of toluene in a bottle. Results: The results showed 98% of toluene in the bottle was degraded by the microbial consortium. In addition, the use of cutting oil significantly decreased kla (from 3.8 to 0.37). Concerning bioscrubber performance, the use of cutting oil as the organic phase increased the efficiency and elimination capacity from 22.5 to 55 and from 34 to 69, respectively, in the case of oil in water. The elimination rate of toluene increased as 32.5% by adding the cutting oil.