Enhancing the Biological Oxidation of H 2 S in a Sewer Pipe with Highly Conductive Concrete and Electricity-Producing Bacteria.

Hydrogen sulfide (H 2 S) generated in sewer systems is problematic to public health and the environment, owing to its corrosive consequences, odor concerns, and poison control issues. In a previous work, conductive concrete, based on amorphous carbon with a mechanism that operates as a microbial fuel cell was investigated. The objective of the present study is to develop additional materials for highly conductive concrete, to mitigate the concentration of H 2 S in sewer pipes. Adsorption experiments were conducted to elucidate the role of the H 2 S reduction. Additionally, electricity-producing bacteria (EPB), isolated from a municipal wastewater treatment plant, were inoculated to improve the H 2 S reduction. The experimental results showed that inoculation with EPB could decrease the concentration of H 2 S, indicating that H 2 S was biologically oxidized by EPB. Several types of new materials containing acetylene black, or magnetite were discovered for use as conductive concrete, and their abilities to enhance the biological oxidation of H 2 S were evaluated. These conductive concretes were more effective than the commercial conductive concrete, based on amorphous carbon, in decreasing the H 2 S concentration in sewer pipes.