Technical optimisation of nitrate removal from ground water by electrodialysis using a pilot plant Original Research Article

Pollution of ground and surface water by nitrate is a worldwide preoccupation. Deleterious effects of nitrate on health are well known. An electrodialysis operation using a pilot plant with a capacity of 24 m3/d has been conduced to optimise industrial conditions to remove nitrate from ground water in the centre of Morocco. Influence of the nature and of the concentration of the electrolyte on rinse and on concentrate streams were studied. The optimisation was carried out on the basis of the following parameters: correlation between demineralisation-denitratation, recovery rates, power and reagent consumptions. Electrodialysis operation was conducted continuously during a long time, under the optimised condition to control the constancy of the electrodialysis plant performances. The treatment of the brine stream (1000 ppm) by a bioreactor, previously optimised, allowed reduction of nitrate content to a raw water content (100 ppm). Optimised technical and economical conditions were proposed to reduce nitrate for the ground water studied.