Electrocoagulation

There are many brands of electrocoagulation devices available, and they can range in complexity from a simple anode and cathode to much more complex devices with control over electrode potentials, passivation, anode consumption, cell REDOX potentials as well as the introduction of ultrasonic sound, ultraviolet light and a range of gases and reactants to achieve so-called Advanced Oxidation Processes for refractory or recalcitrant organic substances.

[1] With the latest technologies, reduction of electricity requirements, and miniaturization of the needed power supplies, EC systems have now become affordable for water treatment plants and industrial processes worldwide.

It effectively removes suspended solids to sub-micrometre levels, breaks emulsions such as oil and grease or latex, and oxidizes and eradicates heavy metals from water without the use of filters or the addition of separation chemicals [3] A wide range of wastewater treatment techniques are known, which includes biological processes for nitrification, denitrification and phosphorus removal, as well as a range of physico-chemical processes that require chemical addition.

A large one-thousand gallon per minute cooling tower application in El Paso, Texas illustrates electrocoagulations growing recognition and acceptance to the industrial community.

It is generally accepted[citation needed] that coagulation is brought about primarily by the reduction of the net surface charge to a point where the colloidal particles, previously stabilized by electrostatic repulsion, can approach closely enough for van der Waals forces to hold them together and allow aggregation.

Electrocoagulation offers an alternative to the use of metal salts or polymers and polyelectrolyte addition for breaking stable emulsions and suspensions.

These species neutralize the electrostatic charges on suspended solids and oil droplets to facilitate agglomeration or coagulation and resultant separation from the aqueous phase.

These processes, however, tend to generate large volumes of sludge with high bound water content that can be slow to filter and difficult to dewater.

These treatment processes also tend to increase the total dissolved solids (TDS) content of the effluent, making it unacceptable for reuse within industrial applications.

When connected to an external power source, the anode material will electrochemically corrode due to oxidation, while the cathode will be subjected to passivation.

In the EC process the water-contaminant mixture separates into a floating layer, a mineral-rich flocculated sediment, and clear water.

The clear, treated (supernatant) water is typically then pumped to a buffer tank for later disposal and/or reuse in the plant's designated process.