In order to remove toxic heavy metals from municipal wastewater sludges, the ex situ electrokinetic technique was studied at pilot scale. This study focused on the feasibility of the electrokinetic removal of heavy metals from sludge and the effectiveness of this technique on the variations of abiotic (physicochemical) and biotic (intracellular and extracellular) speciations of heavy metals using several analytical methods. Even though the sludge used was taken from a municipal wastewater treatment plant, the sludge contained relatively high concentrations of target metal contaminants (Cd=6.8mg/kg, Cr=115.6mg/kg, Cu=338.7mg/kg, and Pb=62.8mg/kg). The removal efficiencies of heavy metals were significantly dependent on their speciations in the sludge matrices. The electrokinetic removal efficiencies of abiotic heavy metals exceeded 70% for the mobile and weakly bound fractions, such as, the exchangeable and carbonate fractions and were lower than 35% for the strongly bound fractions, such as, the organic/sulfide and residual fractions. In the case of the biotic heavy metals, the removal efficiencies of the extracellular fractions were slightly higher than those of the intracellular fractions.
Bibliographical noteFunding Information:
This research was supported by the Korea Institute of Science & Technology Evaluation and Planning (KISTEP) through the National Research Laboratory (Cleaner Separation Laboratory) at Kwangju Institute of Science and Technology (K-JIST), Korea. One of the authors (S.-O.K.) is grateful to Brain Korea 21 from the Ministry of Education through the Department of Earth and Environmental Sciences at Korea University for awarding a Post Doctoral Research Position.
- Heavy metals
- Pilot-scale electrokinetics
- Removal efficiency
ASJC Scopus subject areas
- Ecological Modelling
- Water Science and Technology
- Waste Management and Disposal