Field Studies on Sediment Remediation

Kenneth Wittle, Sibel Pamukcu, Dave Bowman, Lawrence M. Zanko and Falk Doering 

In this chapter, field study experiences with an alternative sediment remediation technology known as electrochemical geo-oxidation (ECGO) are presented. The chapter provides conceptual, technological, and operational context for ECGO, focusing on in situ and ex situ field applications of the technology in Duluth, Minnesota, USA, from 2002 to 2007, and on a 20 ex situ application in Copenhagen, Denmark. 

Electrochemical Remediation Technologies for Polluted Soils, Sediments and Groundwater, Edited by Krishna R. Reddy and Qaudio Cameselle Copyright 2009 John Wiley Sons, Inc. 

This difference in efficiency can be attributed to several complicating factors which contributed to the Duluth outcome, the most significant of which is the unanticipated but overwhelming influence of solid-phase particulate coal tar on both sampling and analytics. These factors and additional analytical results are discussed and presented in greater detail in the remainder of this chapter, as are lessons learned and related recommendations and observations. 

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Wittle JK, Pamukcu S, Bowman D, Zanko LM, Doering F (2009) Field studies on sediment remediation. In Reddy KR, Cameselle C (eds) Electrochemical remediation technologies for polluted soils, sediments and groundwater. Wiley, Hoboken, pp 661-696... 

The models described in Section 10.3 are whole system models that include all processes involved in the transport and fate of contaminants in aquatic systems. Application of these models therefore demonstrates how particle deposition and resuspension affect the transport and fate of contaminants associated with those particles. The case study presented in Section 10.4 for the Lower Fox River is an example of how research knowledge and appropriate field data collection on sediment deposition and resuspension processes (reviewed in Section 10.2) have been incorporated into conceptual and numeric models (reviewed in Section 10.3) that support assessment and remediation of contaminated sediment sites. 

The potential of electrokinetic remediation technology has been demonstrated for the remediation of mixed metal-contaminated soils, sediments, and groundwater over the past decade. Various enhancement schemes have been developed by the laboratory experimental and field applications, such as electrolyte conditioning and electrodialytic remediation. Despite such advances in the technology, it still has some limitations on the removal of mixed metal contaminants, including several specific heavy metals such as Cr, As, and Hg. Finding a simultaneously applicable process for the remediation of mixed heavy metals wUl require further study. 

The electrokinetic technology for the remediation of soils, sediments, and groundwater relies on the application of a low-intensity electric field directly to the soil in the polluted site. The effect of the electric field mobilizes ionic species that are removed from the soil and collected at the electrodes. At the same time, the electric field provokes the mobilization of the interstitial fluid in the soil, generating an electroosmotic flow toward the cathode. The electroosmotic flow permit the removal of soluble contaminants. The success of the electrokinetic process rely on the effective extraction and solubilization of the contaminant and on their transportation toward the electrodes, where they can be collected, pumped out, and treated. Many studies have been carried out to determine the influence of the operating conditions and the effect of the soil and contaminant nature in order to improve the applicability and effectiveness of the electrokinetic treatment. 

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