Electroremediation of heavy metals in sewage sludge

Abstract

-This paper presents the application of electrokinetic remediation in the treatment of sludge in a sewage treatment station. The study consisted of, in a first step, the characterization of physicochemical parameters of sludge and, in a second step, the implementation of the electrokinetic remediation technique. The concentrations of Cu, Cr, Pb and Zn in sludge samples, before and after the experiment, were determined by atomic absorption spectroscopy. After 40 hours of experiment, considering an electrolyte flow-rate of 1.34 L.h -1 at a voltage of 20 V, the removal rate of all the metals accompanied was over 50%; the highest removal efficiency was for Pb, with 72.49%. The results show the feasibility of using the electrochemical technique of electrokinetic remediation for metal removal from a sludge sewage treatment station.

Removal of Toxic Metals from Sewage Sludge Through Chemical, Physical, and Biological Treatments—a Review

“…The principle of this method is the application of a low electric current directly to the substrate or the application of a potential between electrodes on the substrate. In this way, contaminants can become charged, mineralized and mobile, facilitating their removal (Elicker et al 2014).…”

“…One of the problems with these metals is that, unlike most pollutants, they cannot be degraded. As a result, when present in food sources containing industrial waste, they can eventually be swallowed and metabolized by plants and animals, and bioaccumulate (Elicker et al 2014).…”

“…Many techniques have been employed in an attempt to improve the physical and chemical characteristics of sewage sludge and remove the toxic metals it contains. Among the most common physical treatments are heat treatment (Shi et al 2013) and electroremediation (Elicker et al 2014), while the addition of organic acidifying and inorganic products (Deng et al 2009) or ionic reagents (Fuerhacker et al 2012) or chelating (Wu et al 2015) are considered the most common forms of chemical treatment.…”

Acidic Removal of Metals From Fluidized Catalytic Cracking Catalyst Waste Assisted by Electrokinetic Treatment

“…Controlling pH throughout the reactor is important because lower pH values favor the desorption of the adsorbed metals on the catalyst (Elicker et al, 2014) and also promote the dissolution of the precipitated contaminants (Giannis et al, 2010).…”

“…This technique was used originally by Yeung and Accar (Yeung et al, 1997;Puppala et al, 1997;Acar et al, 1995;Yeung et al, 2011) to treat soils contaminated with metals and is based on applying a direct current of low intensity or a low electrical potential difference through electrodes in the soil. Other studies (Acar et al, 1995;Yeung, 2011;Yang and Lin, 1998;Alshawabkeh et al, 1999;Pamukcu et al, 2004;Wang et al, 2007;Guaracho et al, 2009;Ma et al, 2010, Elicker et al, 2014 related to EKR have illustrated its feasibility and effectiveness in treating soil in situ without having to remove it from the site, thus making the process cost-effective compared with other methods. According to Li et al (2012), EKR techniques can also be applied in mine tailings, sewage sludge, and marine sediments because electrokinetic techniques may be applied in any permeable medium that is ionically conductive.…”