Electrocoagulation is a technique used to treat wastewater, industrial process water, and ground/surface water by introducing an electric current to sacrificial metal electrodes placed in the water. During electrolysis, ions are released from the anodes that neutralize particle charges in the water, causing contaminants to coagulate and be removed. It has been shown to effectively remove suspended solids, oils, heavy metals, organic compounds, bacteria and viruses. While electrocoagulation can be an expensive process and issues like electrode passivation can reduce efficiency, it has wide applications in water treatment for industries, sewage, and pretreatment.
2. WHAT IS ELECTROCOAGULATION???
๏ Technique used for wash water treatment,
wastewater treatment, industrial processed
water, and medical treatment.
๏ It has proven very effective in the removal of
contaminants from water.
๏ Electrocoagulation systems have been in
existence for many years using a variety of
anode and cathode geometries.
3. Fig. 1) Bench-scale EC reactor with mono
polar electrodes in series connection
4. METHODOLOGY
The conductive metal plates
are commonly known as
โsacrificial electrodes.โ The
sacrificial anode lowers the
dissolution potential of the
anode and minimizes the
passivation of the cathode.
Mono polar electrodes with
cells are arranged in series. In
series cell arrangement, higher
potential difference is required
for a given current to flow
because cells connected in
series have higher resistance
During electrolysis, positive
side undergoes anodic
reactions, while on negative
side, cathode reactions are
encountered. Coagulation
process will initiated by
neutralizing charges of
particles by released ions.
The released ions remove
undesirable contaminants
either by chemical reaction
and precipitation, or by
causing the colloidal materials
to coalesce, which can then
be removed by flotation.
5. Water containing colloidal
particulates, oils, or other
contaminants move through
the applied electric field,
there may be ionization,
electrolysis, hydrolysis, and
free-radical formation which
can alter the physical and
chemical properties of water
and contaminants.
The reactive and excited
state causes
contaminants to be
released from the water
and destroyed or made
less soluble.
7. COMPARISON
๏ Advantages
I. Removes heavy metals
as oxides that pass
Toxicity characteristic
leaching procedure
(TCLP)
II. Removes suspended
and colloidal solids,
Breaks oil emulsions in
water.
III. Removes fats, oil, and
grease.
IV. Removes complex
organics
V. Destroys and removes
bacteria, viruses and
๏ Disadvantages
I. The use of electricity may
be expensive in many
places.
II. An impermeable oxide
film may be formed on the
cathode leading to loss of
efficiency of the EC unit.
III. High conductivity of the
wastewater suspension is
required.
IV. Gelatinous hydroxide may
tend to solubilize in some
cases.
8. APPLICATIONS OF ELECTROCOAGULATION
๏ Ground Water Cleanup
๏ Surface Water Cleanup
๏ Process Rinse Water and Wash Water
๏ Sewage Treatment
๏ Cooling Towers
๏ Water Pretreatment
