Treatment and recovery of contaminated railway ballast

Abstract

Experimental tests of metal extraction from stones sampled from artificially contaminated railway ballasts are presented and discussed. Metal extraction was performed by washing with aqueous solutions of disodium ethylenediaminetetraacetate (EDTA), at selected concentrations. The effectiveness of the remediation process was evaluated using leaching tests.The results indicate that the washing technology represents a successful and affordable solution for the implementation of an on-site treatment aimed at a reuse process. Adopting a 0.05 M EDTA solution, extraction yields in the range between 40% and 70% were achieved, depending on contact time and pH of the washing solution.

Investigation of Heavy Metal Sources on Railways: Ballast Layer and Herbicides

“…Di Palma & Petrucci [2014] showed that only a slight release of Cu and Zn was observed for the uncontaminated ballast stones. The Cd concentration in the leachate was always below the a) b) Fig.…”

Biosequestration of chromium(iii) in an aqueous solution using cationic and anionic biosurfactants produced from two different Bacillus sp. – a comparative study

“…The various parameters that signicantly affect the production of biosurfactants using palm oil and coconut oil as substrates, such as time (24-120 h), pH (1)(2)(3)(4)(5)(6)(7)(8)(9)(10), temperature (20-50 C) and concentration of substrate (10-60 g L À1 ), were optimized using one parameter at a time while the other parameters were kept constant. The most signicant range of parameters was further optimized using Response Surface Methodology (RSM) for the production of the biosurfactant.…”

“…5 Cr(III) tends to be strongly bound by soil humic acid polymers, and this affinity restricts the availability of Cr(III) to be oxidized and reduces the decomposition of organic matter. 6 Cr(III) in soils could be leached into surface water or groundwater and be absorbed by plants. 5 Chromium(III) enters the human food chain through the consumption of the vegetative plants.…”

Railway ballast fouling, inspection, and solutions - A review

“…102 In addition, for metal pollution, a washing test aimed at metal extraction from stones sampled from artificially contaminated railway ballasts is presented and discussed. 103 Metal extraction was performed by washing with aqueous solutions.…”