AN ANALYTICAL APPRAISAL OF WORLDWIDE CONTAMINATED DREDGED MATERIAL MANAGEMENT APPROACHES

摘要

The issues regarding the management of contaminated sediments most commonly arise as a result of dredging (capital dredging and maintenance dredging). Dredging is an economically essential activity to most countries and offers a solution to the problems of siltation of channels and trends of increasing ship sizes and is also important in waterside developments. In a few circumstances, countries undertake the remediation of problem sites and remove or clean up contaminated sediments for environmental reasons (environmental dredging). This paper reviews results from a number of recently reported research and consultancy projects dealing with dredging operations and the disposal of contaminated sediments from around the world. The objective of the paper is to evaluate worldwide practices and advances in the management of contaminated dredged material. Examples of recent advances are given by exploring case studies from Hong Kong, North America and Europe and include; the use of capping; confined disposal facilities; advances environmental assessment and modelling tools; and the implementation of novel technologies for decontaminating sediments for port developments. Appropriate characterisation of the sediments is important and there is a present shift towards an increased emphasis in biological testing and the assessment of ecological quality. The majority of treatment technologies are, at present, a long way from being economically applicable for many sites and technological advances in confined disposal facilities (CDFs) and confined aquatic disposal (CAD) options are likely to play a large role in the near future for the management of contaminated sediments. International effort and lessons learnt need to be shared.