About Wapulec OY
Wapulec OY project was initially developed as a result of successful cooperation between the Department of Chemical Technology of Lappeenranta University of technology (Finland) and Institute of High-Technology Physics of Tomsk Polytechnic University (Russia).
In 2010 the company WAPULEC OY based in Lappeenranta, Finland has been established. The company employed specialists from both institutions, bringing together the experience on chemical technology, water treatment, high-voltage engineering and design of ozonizers and electric discharge devices Wapulec project has been awarded the 1st prize at the innovation contest ofthe I EU-Russia innovation forum (2010). Currently the company is running several pilot projects on water treatment and disinfection with industrial companies in Finland. WAPULEC is a new technology of water treatment. It provides oxidation of pollutants with active oxidant species (hydroxyl radical, atomic oxygen, ozone) produced by pulsed electrical discharge directly on the surface of treated water in air or oxygen atmosphere.
Advanced water treatment technology
WAPULEC, being an acronym comprised of “WAter”, “PUlse” and “eLECtricity” stands for a novel method and device of water treatment. The technology provides oxidation of pollutants with active oxidant species, such as hydroxyl radical, atomic oxygen, and ozone, produced by gas-phase pulsed electric discharge directly on the surface of treated water in air or oxygen atmosphere.
Water treatment by electric pulsed corona discharge
Water treatment in WAPULEC device occurs due to electric pulsed corona discharge (PCD) in a gas medium, to which water is showered in droplets, jets and films directly to the discharge zone.
Pulsed corona discharge is formed in air or oxygen at atmospheric pressure and propagates in a form of multiple low-energy channels called streamers, uniformly distributed over the volume between electrodes. The discharge takes place between two electrodes of highly non-uniform geometry, e.g. using a thin wire as high-voltage electrode, and a grounded plate, resulted in a concentrated electric field at the wire. The corona glow appears at the high-voltage electrode. To avoid transition of corona glow to a spark, high-voltage pulses of short duration are applied to the electrodes.
Pulsed corona is an effective source of active oxidant species, such as hydroxyl radical (OH), atomic oxygen (O) and ozone (O3), known as the most powerful oxidizers. Hydroxyl radical and atomic oxygen are formed on the surface of water droplets, so they easily react with the impurities in water. Oxygen-based oxidizers are safe for the environment – they are decomposed shortly after their formation in the discharge. Unlike chlorine, they do not form toxic byproducts (trihalomethanes), therefore reducing risk to human health.
Results of oxidation are:
- Decomposition of organic substances (they are either completely mineralized to water and carbon dioxide or transformed into less toxic compounds)
- Transformation of inorganic substances (e.g. iron, manganese) into insoluble forms, easily removable by mechanical filtration or precipitation.
- Abatement of microorganisms (water disinfection)
Advantages of the pulsed corona discharge water treatment method
Effective energy consumption Energy efficiency of pollutants oxidation in pulsed corona discharge treatment of water exceeds the one of conventional ozonation for at least three times.
Simplicity and high reliability of equipment Electric discharge device is simple and needs no additional gas preparation, such as dust removal, cooling and drying. The pulse generator, designed with the use of modern semiconductor appliances and magnetic switches, is highly reliable and does not require expensive servicing.
Minimum chemical requirement: no chemicals are required except oxygen for improved oxidation efficiency; enrichment with oxygen is optional, the method works with air effectively enough. Active oxidizers – radicals, atomic oxygen, ozone – are produced “in situ” by pulsed corona discharge from oxygen and water.
Wide range of oxidizable substances: aromatic compounds, oil products, organic acids, amines, natural organic matter, pesticides etc. Some substances, resistant towards conventional treatment with ozone, are susceptible to oxidation with pulsed corona discharge.
Waste water treatment
Phenol was removed from aqueous solutions containing 100 mg/L with the efficiency from 70 to 110 g/kWh.
Various wastewaters were tested in PCD treatment. High removal efficiency was achieved with lignin, furfural, pesticides and pharmaceutical industry wastes.
Potable water treatment
Natural organic matter (humic substances) was removed with high energy efficiency. Colour reduction from 100 to 10 degrees was achieved with the energy dose of 250 Wh/m3.
Disinfection/bacterial control of lake water was verified at the pulsed energy dose 30 Wh/m3
Applications of WAPULEC technology
- Potable water treatment
- Waste water treatment
- Recycling water treatment
- Water disinfection