Counter-Current Attrition Process (CCAP) to Remove Metals, Pentachlorophenol (PCP), Dioxins and Furans (PCDDF) from the 1-4-mm Fraction of Contaminated Soil

Abstract

The objective of this study was to evaluate the potential of a counter-current attrition process (CCAP) over 15 cycles for removing metals, pentachlorophenol (PCP) and polychlorinated dibenzo-p-dioxins and-furans (PCDDF) from contaminated soil. The CCAP, applied to the 1-4mm fraction of a contaminated soil, included five attrition steps (pulp density (PD) = 40% (w w-1), surfactant [BW] = 2% (w w-1), t = 20 min, T = 20°C) followed by one rinsing step. The water emerging from the first attrition step was treated using flocculation in the presence of 0.04 g CMX 123 (commercial flocculent) L-1 before being reintroduced into the CCAP. The CCAP including the treatment of attrition wastewater (ATW) by flocculation achieved a removal of 44 ± 5% As, 26 ± 6% Cr, 24 ± 5% Cu, 49 ± 4% PCP and 45 ± 3% PCDDF. Moreover, the CCAP enabled a significant reduction (78%) in the amount of water required (around 14.5 m 3 of water per ton of the 1-4-mm soil fraction). The high removal yields obtained after 15 attrition cycles of the CCAP for PCP and PCDDF and the significant reduction of water consumption confirm that this CCAP can be considered for industrial applications.

Techno-economic assessment of an hydrometallurgical process to simultaneously remove As, Cr, Cu, PCP and PCDD/F from contaminated soil

“…The results showed that the contaminant removal yields obtained during 15 loops of the CCAP varied between 32 and 52% for As, 17 and 37% for Cr, 15 and 37% for Cu and 41% and 50% for PCDD/F. The removal yields of attrition observed in the present study were similar than those obtained by Guemiza et al (2017b) for the removal of metal(loid)s but higher for PCDD/F. The higher removal yields of organic contaminants in the current study can be explained by the higher initial concentration of PCDD/F in the S3 soil.…”

“…The first series of the five attrition steps (L1) was conducted using fresh water. As mentioned by Guemiza et al (2017b), wastewater from the first stage of attrition is treated by flocculation-decantation in order to remove some of the contaminants (e.g. suspended matter).…”

“…Although the coarse fractions, which represent the majority of the entire soil (87%), had low initial metal(loid)s concentrations, the CCAP was efficient enough to reduce them below the criteria to allow an industrial use of the remediated coarse fractions. In comparison, Guemiza et al (2017b) evaluated the performance of CCAP to remove metals, PCP and PCDD/F from the 1-4 mm fraction of contaminated soil. The results showed that the contaminant removal yields obtained during 15 loops of the CCAP varied between 32 and 52% for As, 17 and 37% for Cr, 15 and 37% for Cu and 41% and 50% for PCDD/F.…”

Recent Developments Studies on Wood Protection Research in Academia: A Review

“…They concluded that the levels of chlorinated phenolic compounds generated by PCP were below detection threshold. Guemiza et al (2017) investigated the use of counter-current attrition process (CCAP) to remove contaminants from soil including PCP. The CCAP treatment achieved a removal rate of 49% for PCP and was considered a suitable solution for industrial applications.…”