Electrocoagulation In Waste Water Treatment

Electrocoagulation is an electrochemical waste water treatment technique in which a metal electrode (usually iron or aluminum based acting as an anode) is attached to the positive end of a DC generator thus oxidizing the metal and producing ferric or aluminum ions. These ions act as a coagulating agent adsorbing to suspended solids colloidal particles thus reducing their negative surface charge and promoting flocculation or reacting with pollutants such as fluoride. It is also possible that on this electrode, organic pollutants are oxidised.

On the other electrode (the cathode) reduction of water molecules occurs thus producing hydroxide ions and hydrogen gas. The hydroxide ions act as a precipitating agent reacting with pollutants such as heavy metals. The hydrogen generated acts as a floatation agent helping flocs to rise to the surface where they can be skimmed off.

The advatange of electrocoagulation over classical chemical coagulation is that the TDS of the solution is not increased.

An interesting paper on this technology can be found here.

Some companies that have commercialized electrocoagulation are listed below:





Compiled by Rami E. Kremesti M.Sc.