Corrosion of concrete sewers is associated with the biological oxidation of hydrogen sulfide to sulfuric acid by bacteria of the genus Thiobacillus. Inhibition of acid production by these organisms, was investigated by challenging established cultures with a heterotrophic competitor
under controlled conditions. Two-organism competition experiments (T. thiooxidans or T. neapolitanus versus the heterotrophic competitor) were conducted in a bench-scale, continuous-flow, constantly stirred tank reactor. Results were sensitive to the influent nitrogen:carbon
ratio. Under conditions designed to produce nitrogen-limited growth, the numbers of thiobacilli were reduced 60- to 1 200-fold after introduction of the competitor. Effluent sulfate concentrations, an indicator of acid production, dropped by 85%. Under carbon-limited conditions, modest reductions
in thiobacilli cell density and effluent sulfate concentration were observed. Microbial competition reduced acid production under the conditions of the experiment. The results suggest that strategies based on competitive displacement of thiobacilli to inhibit corrosion of concrete sewers may
Water Environment Research® (WER®) publishes peer-reviewed research papers, research notes, state-of-the-art and critical reviews on original, fundamental and applied research in all scientific and technical areas related to water quality, pollution control, and management. An annual Literature Review provides a review of published books and articles on water quality topics from the previous year. Published as: Sewage Works Journal, 1928 - 1949; Sewage and Industrial Wastes, 1950 - 1959; Journal Water Pollution Control Federation, 1959 - Oct 1989; Research Journal Water Pollution Control Federation, Nov 1989 - 1991; Water Environment Research, 1992 - present.