Remediation of Materials with Mixed Contaminants

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issn 1650-6278 isbn 978-91-7668-683-6

Kristin Elgh-Dalgren holds a master degree in soil science from the Swedish University of Agriculture, and has been a postgraduate student in environmental science at the multidisciplinary Man-Technology-Environment (MTM) Research Centre at Örebro University, where the work of her Ph.D. thesis was performed.

Soil contamination is a large issue worldwide and much effort has been made to find efficient remediation meth-ods. At many of the contaminated sites, mixtures of different contaminants are present, which may lead to additional problems in the remediation process due to the different properties of the contaminants. It is thus desirable to find treatment technologies which are efficient and yet at low cost.

This thesis presents the results from laboratory and pilot scale soil remediation of two soils containing mixtures of both organic and inorganic contaminants, originating from an old military field (explosives and heavy metals) and a wood preservation site (PAH and arsenic). Two different remediation techniques were evaluated: bioremediation to degrade the organic contaminants with simultaneous monitoring of the inorganic co-contaminants, and soil wash-ing to simultaneously remove both the organic and inorganic contaminants. In addition to the commonly utilized chemical analysis, the efficiency of the

soil remediation was monitored by toxicity tests (Microtox®_{), which gives}

information of the overall soil health status.

After remediation, re-cycling of the remediated soil is desirable. In Sweden, however, cycling has so far been limited. The main constraint against re-cycling is the risk of spreading of pollutant remains, and thus risk assessment often includes different leaching tests. Two standardized leaching procedures and three leaching solutions were evaluated on four soils which had under-gone large scale soil washing, to study the possibility to re-cycle these soils according to three different legislations.

Remediation of Materials with Mixed Contaminants

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