Electrodialysis of groundwater with heavy metal and nitrate ions under low conductivity and effects of superficial velocities

Abstract

The efficiency of separation of lead, manganese, arsenic, and nitrate from groundwater with relatively low conductivity by electrodialysis (ED) was investigated. The effects of the superficial velocities in either the diluate or concentrate cell were also evaluated to understand the relative separation rate of the four ionic compounds by ED and to examine the possibility of reducing the energy for pumping. Significant removal (i.e. 92.8–99.2%) of manganese, arsenic, and nitrate from Ilgam (Seoul, Korea) groundwater was achieved, along with removal (61.3%) of lead comparable to that of Sungbuk (Seoul, Korea) water. The superficial velocity in the concentrate cell exerted no effects on either the conductivity or current reduction, or on the separation ratios. The superficial velocity in the diluate cell increased the operation time required to obtain the requisite conductivity reduction, but exerted little effect on the separation ratios. ED could be performed at reduced water velocity to treat groundwater with low conductivity.

Keywords:

• Electrodialysis
• Heavy metal
• Nitrate
• Separation
• Superficial velocity

Acknowledgment

This work was supported by the Korea Ministry of the Environment as “The GAIA project (2014000550005)”.

Notes

Presented at the 8th International Desalination Workshop (IDW) 2015, November 18–21, 2015, Jeju Island, Korea