Remediation of sediments contaminated with heavy metals and organic matter by environment-friendly leaching process

The sediments near coasts and ports in Korea have been found to be contaminated with heavy metals and organic matters. So far the sediments have been dumped to landfill sites or ocean. However, the number of available landfill sites is decreasing and ocean disposal of wastes was strictly prohibited. Although physical separation processes have been found to be useful for the remediation of contaminated soil with heavy metals, because the sediments consist of fine particles, it is difficult to remove heavy metal component by physical separation processes. Furthermore, the sediments contain organic matter, so there is a concern about strong stink during the sediment treatment. The present study is aimed to develop the treatment process for removing heavy metals and organic matter from the contaminated sediments. The heavy metals and organic matter were oxidized and dissolved by electro-generated chlorine, and the chlorine used is regenerated and circulated in the leaching process. This system has economic and environmental advantages to reduce the wastewater and the oxidant consumption. The leaching results show that the metal removal efficiency increased to more than 99%, and more than 50% of organic matter was decomposed.