Effects of some factors on electro-osmotic dewatering of Laterite

Abstract

Preliminary analyses to determine some geotechnical properties of two soil samples A and B collected from Osun State, Nigeria were carried out. Soil samples passing through sieve with 0.425 mm opening were prepared to different moisture contents (60 or 80%) and poured inside a rectangular electrochemical cell. Direct Current voltage (20 or 40 V) was applied across the moist soil using steel plate electrodes inserted at the end of the soil. The spacing of the electrodes was varied (10 or 20 cm). The electrochemical treatment time was 360 min. The Electro-osmotic (EO) flow was recorded at every 30 min during the experiment A factorial experiment was performed to determine the factor that had most significant effect on the EO flow. The factors varied were electrode spacing (S), applied voltage (V) and initial moisture content (M). The results showed that S was inversely proportional to the EO flow, while V and M were directly proportional to the EO flow. The initial moisture content (M) has the highest estimated effect (91.825 and 243.35 for samples A and B, respectively) and thus the most significant effect on the EO process. The general effects were same for the two soil samples, but the rate of the effect varied, which implied that EO dewatering was site dependent. It was concluded that EO dewatering was a viable option for dewatering of tropical laterite.

Keywords: Electro-osmosis, Soil Dewatering, Tropical Laterite,