Ocean dumping of municipal sewage sludge (MSS) that was treated in wastewater treatment plants in the Republic of Korea (ROK) began in 1993 and has sharply increased thereafter; this deteriorated the benthic environment of the dumping sites, consequently necessitating relevant policies to be developed to reduce dumping. This review introduces the outcomes of policies used to phase out ocean dumping of MSS in ROK and provides a method for improving contaminated environments. We first review a previous report submitted under the London Protocol in 2016 and then provide additional data collected since then. In addition, we introduce a scientific research result that reduced the concentration of harmful substances in the dumping sites by capping the dumping area. ROK established policies to phase out the dumping in 2006, which had immediate impacts, with dumping of MSS terminated in 2012. These policies were then expanded to terminate dumping of all types of sewage sludge in 2016, due to the fast and strict application of actions based on intergovernmental cooperation and societal consensus. In addition, the capping method that covered the contaminated sediments with dredged materials was effective. The success of the evaluated policies and research could be effectively applied to areas with similar circumstances.

Since the late 1980s, in efforts to reduce the burden of waste treatment on land and to protect the nation’s rivers, the Korean government has licensed dumping at sea only for waste difficult to treat on land. However, owing to the “not in my backyard” (NIMBY) phenomenon and the higher cost of land-based treatment, the amount of ocean-dumped waste has increased rapidly. The categories of waste dumped have also expanded to include sewage sludge containing highly concentrated hazardous substances, raising concerns about damage to the marine environment. The Korean Ministry of Oceans and Fisheries has noted that compliance with the London Protocol could be essential for limiting ocean dumping activities. The Republic of Korea enacted comprehensive measures to ensure compliance and formally acceded to the London Protocol in 2009. This paper presents Korea’s implementation of the criteria that led to the cessation of ocean dumping of sewage sludge in 2016.