Electrochemical technologies offer very promising field in water and wastewater treatment. Processes are usually simple and easy to build in different environments and scales. Effective removal of pollutants occurs either by electrochemical coagulation, oxidation or flotation.
Ongoing research in laboratory
Electrochemical oxidation is an effective electrochemical technique which is used for oxidation of different kind of wastewaters. Many organic substances (like phenols) have been degraded successfully and inactivation of bacteria and bacteriophages in domestic waters has given promising results. This technique is also environmentally friendly because any chemicals in the oxidation process need be used.
Electrochemical coagulation is a promising wastewater purification technique which is also already in use in some applications. Electrodes are already known (Fe and Al) but still lots of research can be done optimising the parameters and finding out effectiveness in different applications. In EC treatment Fe- and Al-electrodes are used to release Al3+ and Fe2+ -ions which will coagulate organic and inorganic material from wastewater.
Electrokinetic remediation is technology, which aims to remove heavy metals, organics and radionuclides from contaminated soil, sludge, wood and other, contaminated media. It involves an application of a low level direct current (40 – 100 mA, which induces the movement of ionic species in the media-water solution towards the oppositely charged electrode (electro-migration), a bulk flow of moisture present in the contaminated media from the anode to the cathode (electro-osmosis) and a movement of charged particles or colloids in the applied electric field (electrophoresis).
Electric field application through e.g. the sludge segment causes electro-osmotic phenomenon which is fluid flow in charged particle matrix. Due to electro-dewatering, electro-osmosis is reported to reduce the interstitial and some of the vicinal water, thus resulting in a dryer sludge cake.
Electro-Fenton process is a technique which can be used for the remediation of soil contaminated with organic contaminants. In electrokinetic Fenton process, hydrogen peroxide passes through low permeability soil from anode to cathode by electroosmosis and produces hydroxyl radicals in the presence of iron in soil. Finally, hydroxyl radicals oxidize or decompose organic wastes.