Evaluating Remediation Efficiency of Functional Oyster Shell Powder for Organically Enriched Sediment

Abstract

Eutrophication is a serious environmental issue in coastal areas, caused by increased nutrient concentration from external sources. Nutrients could augment in the bottom sediment and be released into overlying water, acting as an internal nutrient source. Converted oyster shell powders were used to evaluate the suppression of nutrients release from bottom sediments. Two kinds of oyster shell powder were applied into the sediment in the individual column with the control column. The natural oyster shell powder (NOSP) was composed of calcium carbonate and the functional oyster shell powder (FOSP) was composed of calcium peroxide. In the column where FOSP was applied, pH was increased due to hydrolysis of calcium peroxide in the overlying water. The concentration of dissolved oxygen in the FOSP-treated columns was higher than that of the control column. The FOSP could suppress the release of ammonia nitrogen and phosphates from the sediment into the overlying water. It was proven that FOSP can effectively adsorb phosphates from organically enriched sediments. Overall, the application of FOSP could effectively control nutrient release from the sediment to overlying water and help reduce the eutrophication in the coastal areas.