Olive Oil Mill Wastewater for Remediation of Slag Contaminated Soil
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Olive Oil Mill Wastewater for Remediation of Slag Contaminated Soil Luciano Ferrara • Lucia Panzella • Alessandra Napolitano Italo Giudicianni • Marco d’Ischia • Michele Arienzo
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Received: 6 April 2013 / Accepted: 5 October 2013 / Published online: 20 October 2013 Ó Springer Science+Business Media New York 2013
Abstract Two olive mill wastewaters (OMW) samples, OMWa and OMWb, containing different polyphenolic loads were used for decontaminating an unauthorized dump site in the Campania region, south Italy. In a benchscale experiment, OMWa at pH 6.0 (OMWapH6.0) and 4.7 (OMWapH4.7), OMWb at pH 4.7 (OMWbpH4.7) and OMWa free of the polyphenolic moiety polyphenol-free OMWa (PF-OMWa) were added to the soil for a 96 h contact time. At 96 h, OMWapH4.7 was more effective than OMWapH6.0, with Cd, Cu, Pb and Zn removal percentages of 30.7–68.1. Cd and Pb levels were 6.0 and 915 mg kg-1, respectively, decreasing below the regulatory limits for industrial and commercial areas (15.0 and 1 9 103 mg kg-1, respectively). A threefold decrease in Zn levels was also observed from 13.5 9 103 to 4.3 9 103 mg kg-1. The metal removal efficiency of PF-OMWa dropped from 30.7 % to 15.6 % for Cd and from 37.9 % to 1.3 % for Pb. OMWbpH4.7 at 96 h was more efficient than OMWapH4.7, with mean removal percentages of 32.5 versus 7.8, respectively. Keywords
Metals Illegal dumps Metal chelation
L. Ferrara L. Panzella A. Napolitano I. Giudicianni M. d’Ischia Department of Chemical Sciences, University of Naples Federico II, Complesso Universitario Montesantangelo, Via Cintia, 80126 Naples, Italy M. Arienzo (&) Department of Earth Science, Environment and Resources, University of Naples Federico II, Largo San Marcellino 10, 80138 Naples, Italy e-mail: [email protected]
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Metal contamination of soil is one of the most important environmental problems throughout the world. Remediation techniques include (1) ex-situ soil washing or in situ soil flushing/leaching with (chemical agents); (2) chemical immobilization/stabilization method to reduce the solubility of metals by adding non-toxic materials into the soil; (3) electrokinetics; (4) ex-situ electrodialysis; and (5) phytoremediation by plants (Wuana et al. 2010). Soil washing is frequently used in soil remediation because it (1) completely removes the contaminants, hence ensures the rapid cleanup of a contaminated site; (2) reduces or eliminates long-term liability; (3) may be the most cost-effective solution; and (4) may produce recyclable material or energy. Since metals are sparingly soluble and occur predominantly in a sorbed state, washing the soil with water alone is not expected to remove a significant amount of cations in the leachates; therefore, chemical agents have to be added to the washing water. Chemicals used for soil washing include surfactants, cosolvents, cyclodextrins, chelating agents and organic acids (Wuana et al. 2010). Strong acids attack and degrade the soil crystalline structure at extended contact times. For less damaging washes, organic acids and
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