Reclaiming salt-affected soils using electro-remediation technology: PCPSS evaluation

Abstract

Reclaiming salt-affected soil in arid and semi-arid countries is currently considered a substantial challenge because of water supply deficiencies. Traditionally, salts are removed from soil using either continuous or intermittent washing, which consumes considerable amounts of water. Our motivation for this study is to develop a process for decreasing the reclamation period and total amount of water, and improving the sustainability of reclamation. Recently, we have developed a new generation of soil electro-remediation techniques known as the perforated cathode pipe soil electrokinetic remediation (SEKR) system (PCPSS) for heavy metal removal. PCPSS was investigated for reclaiming salt-affected soils collected from the El-Sallam canal region Egypt. In the present study, enhancement of Na+ removal was firstly investigated using a Taguchi Approach orthogonal array (L9OA). The results indicated that the influential factors improved Na+ removal in the following order: cathode pipe operating time>voltage>cathode gap>hydrostatic head; additionally, the vertical removal above the cathode gap was operating time>hydrostatic head>voltage>cathode gap. A confirmation experiment demonstrated that Mg2+ removal was as high as 41.7% followed by Na+ with 23% removal. Ca2+ removal was the lowest (6.6%), likely due to the formation of insoluble CaSO4. K+ also showed low removal (8.4%), likely because of its comparatively low concentration. The removed cations show the following sequence: Mg2+>Na2+>K+>Ca2+. A large percent of Cl− was removed (53.3%), whereas SO42− showed the lowest removal (5.1%). The accumulative electroosmosis flow was proportional to the voltage followed by operating time, hydrostatic head, and cathode gap, respectively.