The effect of recycled waste oyster shell powder applied to organically enriched marine sediment as oxygen releasing compound

Abstract

Eutrophic influx, being accumulated in marine sediments and its releases into the overlying water body are very important in most of the coastal areas in Korea. Nitrogen and sulfur are regarded as the most attentive elements in the metabolism of the marine ecosystem. The two groups of contaminants could be transformed into corresponding reduced compounds inside the sediment environment and its release into ambient water from sediments may have a significant impact on water quality resulting in increased eutrophication. In order to evaluate the remediation ability of ultrasound treated oyster shell powder (OSP) and raw oyster shell powder (OSP) applied to organically enriched sediments in terms of suppressing nutrient flux and acid volatile sulfides (AVS). The ultrasound treated OSP was found to be oxygenated to rather peroxide as oxygen releasing compound. The application of treated OSP decreased the concentrations of ammonium nitrogen, acid volatile sulfide, and chemical oxygen demand, whilst it increased dissolved oxygen, sulfate, and nitrate concentration significantly in the overlying water compared to the raw OSP applied basin with control. The treated OSP was successfully tested as a controlled oxygen releasing compounds (ORC) in the organically enriched sediment to reduce eutrophication. Denaturing gradient gel electrophoresis (DGGE) and community phylogenetic affiliation analyses revealed that nitrifying/denitrifying bacteria and sulfur-mediating bacteria were positively involved in the simulation experiments. It should be noted that alpha- and beta-Proteobacteria (sulfur-oxidizing bacteria) were commonly identified in the microflora of sediment applied with the oxygenated oyster powder.