Electrochemically activated water (ECA-water) is an environmentally friendly alternative to the current disinfectants. Reducing the use of chemical products is the main advantage.
By using an ECA-unit, electrochemically activated water can be produced on location. The necessary raw materials are softened tap water and natural salt. Potassium chloride (KCl) is usually used in horticulture but sodium chloride (NaCl) can also be used. By passing the salt solution through a module with two electrodes, across which there is an electrical direct current, the salt water is electrolysed. Chlorine gas (Cl2) and oxygen (O2) mostly form at the positive electrode (anode). The chlorine gas dissolves in the liquid to form hypochlorous acid (HClO), in other words active chlorine, and hydrogen chloride (HCl). Hydrogen (H2), that escapes into the outside air, and potassium- or sodium hydroxide form at the negative electrode (cathode).
The advantages:
- Eliminates biofilm in pipes and water systems.
- Eliminates biofilm as hidden place for plant pathogens.
- Disinfecting and cleaning agent avoids clogging.
- Efficient and cost effective.
- Clean and safe water for all horticultural crops.
- No resistance possible.
- Required: softened water and potassium chloride.
More stable product
When using a voltage higher than 4 Volts small amounts of other oxidizing agents, such as hypochlorite, ozone and hydrogen peroxide, may also form. Because the chlorine compounds are more stable than in other chlorinated products, such as bleach, the activity is five times stronger due to its longer period of activity. An advantage is also that the ECA-water reverts to the raw materials from which it is made. Due to the powerful disinfecting ability of active chlorine the activated water has a broad range activity against bacteria, fungi, viruses, algae, protozoa and nematodes. Known applications are for seed disinfection, cleaning of containers and tools, removal of biofilms from pipelines and disinfection of flowers, fruits and vegetables.
Comparison
ECA-water cannot be compared on a one-to-one basis with other disinfection methods. Each method has its own advantages and disadvantages. Water disinfection by UV and heating is called point disinfection, because the water is disinfected at one point in the system. The downside of this disinfection is that it doesn’t control the biofilm and does not keep the pipelines clean. The advantage of activated water is that active chlorine works through the entire water system.
The advantage of UV and heating is its ability to control large changes in the quantity of pathogens. When using ECA-water a sudden increase in organic matter or pathogens requires an adjustment to the dosage of active chlorine. Therefore this requires continual measuring and alteration of the dosage. The use of electrochemically activated water is a good addition to the current method of water disinfection.
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