Simultaneous biological-photocatalytic treatment with strain CDS-8 and TiO2 for chlorothalonil removal from liquid and soil

In this study, a novel chlorothalonil (CTN) degrading bacterial strain CDS-8, identified as Pseudomonas sp., was combined with photocatalyst titanium dioxide (TiO2) for the CTN degradation in liquid and soil. After 7 day incubation, 90.73% of CTN was removed from mineral salt medium (MSM) by CDS-8 with the optimal condition at pH 7.0 and 30 degrees C. Single biodegradation or photocatalytic degradation could not degrade CTN completely, and many toxic and persistent intermediate metabolites remained. However, simultaneous biological-photocatalytic treatments could markedly remove CTN and reduce the chemical oxygen demand (COD) which could not be removed by single biodegradation or, photocatalytic degradation. In MSM, treatment with CDS-8/40 mg L-1 TiO2 showed the highest COD removal rate (84.10%). Furthermore, combined CDS-8/TiO2 treatments could effectively degrade CTN in soil. In treatments with CDS-8/20 mg kg(-1) TiO2 of soil, the maximum CTN removal rate reached 97.55% in turned soils. However, with CDS-8/40 mg kg(-1) TiO2 of soil, the maximum CTN removal rate (94.94%) was found in static soil. In general, the combined biological-photocatalytic treatments provided a promising alternative candidate for the remediation of CTN-contaminated sites. (C) 2016 Elsevier B.V. All rights reserved.