Study of salt removal with evaporation drainage method

摘要

Soil drainage and reclamation is often achieved by soil leaching with fresh water. However, soil leaching is limited by land conditions and the availability of fresh water, A new method called Evaporation Drainage Method that removes excess water andsalts through evaporation from fabric columns, called accelerators, installed in the soil or saline water. Laboratory experiments were conducted to examine the influence of accelerator length and diameter and salt concentration on water drainage throughevaporation and on salt removal. Accelerators with 8 lengths ranging from 60 to 300 mm and 4 diameters ranging from 5 to 30 mm were used. Five saline solutions prepared by mixing KC1 with water at 1, 3, 5, 7, and 10% by weight were used in the experiments. Experimental results showed that accelerators significantly increased water evaporation and salt removal from ponded solution and this increase is directly related to length and diameter of accelerator, and to a lesser degree, salt concentration. A 60-mm long accelerator increased water evaporation by 27% and a 300-mm long accelerator by 100% compared to pan evaporation. A 300-mm accelerator increased salt removal by about 320% compared to the 60-mm long accelerator. Increasing the diameter of the accelerator from 5 to 30 mm increased evaporation rate and therefore salt removal by 160%. High salt concentration slightly reduced evaporation compared to low concentration but increased salt removal from solutions. The total salt removal by a 300-mm longaccelerator in a 1% KC1 solution was 1.2 g compared to 28 g in a 10% KC1 solution representing about 13 and 30% of the total salt in the solution, respectively.