YH Bay marine contaminated sediments cleanup project in Busan, South Korea

Contaminated sediment sites in S. Korea are largely close to residential and business districts in the metropolitan port cities. We report here YH Bay remediation project carried out from 2009 to 2012. The bay was reclaimed in 1962 and 3,800-units of 25^th story residential apartments were subsequently constructed in the reclaimed land from 2001 to 2008. However, two narrow water channels adjacent to the residential apartment complex became the conduits of storm water from the densely populated urban watershed in higher elevation. The bottom sediments of the two channel became highly contaminated with organic matter produced in situ due to the restricted circulation with offshore waters on top of the legacy contaminated sediments. The apartment residents have been suffered from the nuisance odor originated from the organic matter decomposition and filed complaints in 2004, 2006 and 2008 to the local administration. The central administration surveyed the site to find the sediment contaminated with heavy metals of copper, nickel, zinc, lead and mercury as well as organic matter. Administration decided that 59,000 m³ of the contaminated sediment had to be removed and dredged material be placed in near-shore reclaimed facility in the vicinity of YH Bay. As the reclaimed area is subject to the Soil Environment Conservation Act, about 30% of the total dredged material was required to reduce heavy metal contents below the concern level of this Act, particularly for zinc. Through bench scale comparison test, current available best technology among competing vendors was selected.