Preformance of an electrobiochemical slurry reactor for the treatment of a soil contaminated with lindane

The purpose of this research was to evaluate the biodegradation of lindane with simultaneous electricity generation in an electrobiochemical slurry reactor (EBCR). The EBCR was inoculated with a sulfate reducing inoculum acclimated to lindane, further characterized, and batch operated for 30 day at room temperature. No external carbon source and supplementation with a stock solution of sucrose: sodium acetate: lactate was performed in experiments with soil concentrations 66% and 33%, respectively. Electrochemical impedance characterization of the EBCR (concentration of soil was 66%) showed that the equivalent circuit had a high anodic resistance R₁=2064Ω, cathodic resistance R₃ = 192 Ω; and electrolyte/membrane resistance R₂ = 7Ω, totaling a high overall internal resistance R_int of 2263 Ù. During the batch operation, the EBCR showed a 30% lindane removal efficiency along with a maximum volumetric power of 165 mW m^-3. The organic matter removal was very high (72% as soluble COD, NOM) whereas the coulombic efficiency was low (5.4%). In the experiment where the concentration of soil was 66% both cell characteristics and performance significantly improved. The internal resistance as determined by polarization curve was 102 O when the two-electrode sets were connected in parallel. During the batch operation, the EBCR showed a 78% lindane removal, a maximum power of 634 mW m^-3, the organic matter removal was 76%, and coulombic efficiency of 15%. Therefore, it can be concluded that the EBCR exhibited a high lindane removal capability and holds promise for bioremediation of soils with the bonus of electricity generation.