Electrodeionization (EDI) is widely used in many industrial water treatment systems throughout the world. In order to maximize the operating stability and life expectancy of an EDI system they were often designed with double pass RO using caustic injection pretreatment. However, in response to recent efforts to lower the capital expenditure and operating costs of double pass RO water treatment systems (DPRO), design engineers are looking at alternative options.
In high alkalinity feed water applications one economical option is to remove carbon dioxide from the water. Carbon dioxide gas dissociates in water to form HCO3- and CO32-. These ionic species will contribute to the total anionic load to the EDI.
3M Liqui-Cel Membrane Contactors are the superior solution for CO2 removal. They operate under the same principle as a conventional FDA except the air and water contact is minimized with a membrane. Since the membrane pores are 0.02 microns in diameter, particles and other debris cannot pass through the pores to contaminate the RO water.