Application of a Vertical “Electric Sieve” to Mitigate and Prevent
Salinization in Coastal Soil
Abstract
This study explored the application of a Vertical Electrokinetic system
(V-EK) with multilayer electrodes in shallow soil to form an “Electric
Sieve” to mitigate and prevent the soil salinization caused by salts
rising from shallow groundwater in the coastal areas. In the model V-EK
system, the electric resistances of soil column, reversely corresponding
to salinity, at the applied voltages 4, 10 and 20 V were 266, 487 and
1272 Ω, respectively. Meanwhile, lower electrical conductivity (EC,
between 67-230 μs/cm) were observed in the soil within 50 cm below the
surface at the voltages of 10 V and 20 V, which was much lower than the
minimum value (581 μs/cm) of the control with no current applied. For
the control column without EK treatment (0 V), soil in the surface layer
had the highest EC value at 1721 μS/cm due to the salts rising from the
bottom, and the EC values of soil beneath the surface were in the range
of 581-1127 μS/cm. Compared to control column, the level of ions in the
surface soil significantly declined after V-EK treatment, especially for
the column with voltage at 10 V and 20V. When voltage was at 20 V, Na+
was detected at a range of 0.06-0.08mg/g in the surface soil, a
>99% reduction when compared to the controls. Similar
efficacy was observed for chloride (Cl-), in the V-EK column with the
voltages at 10 V and 20V.