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

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