Experimental study of fluid mud consolidation delayed by the methyl trophic bacteria from sediment

Purpose The presence of microbial extracellular polymeric substances (EPS) has been reported to allow channels containing fluid mud to remain navigable for longer. But it is still necessary to find new bacteria that can delay fluid mud consolidation, which can grow in the field without the addition of organic material. With this aim, certain types of inorganic chemoautotrophic bacteria can be screened and used to delay the consolidation of fluid mud. Methods Four kinds of inorganic chemoautotrophic bacteria were assessed in this study in targeted culture tests, namely methyl trophic, sulfur, nitrifying, and iron bacteria, as well as a comprehensive culture. Then, experiments on consolidation with longer test times were conducted to verify the delaying effect of the bacteria newly screened. Results On the whole, the higher the EPS content, the greater the effect of delaying the consolidation. The ratio of the corresponding thickness of the fluid mud layer in a stable condition compared to the initial thickness shows a logarithmic increase with increased EPS content. And the corresponding density of the fluid mud reduces obviously with the increase of EPS content. Conclusion This study screened a new chemoautotrophic methyl trophic bacterium from sediment, identified as Methylophaga SP, which EPS can delay effectively the consolidation of fluid mud. It might be applied in the field to maintain the navigability for longer.