WATA® production of active chlorine
Chlorination, which consists in adding active chlorine (sodium hypochlorite) in water, is the most common method for disinfecting drinking water of parasites, bacteria and viruses. Indeed, active chlorine destroys or inactivates most pathogenic micro-organisms in water with a very high reliability. Generally speaking, it is not produced in low-income countries. It is more typically imported in the form of tablets or bleach, at relatively high cost.
Antenna Technologies has developed a line of WATA line of devices, part of the WATASOL approach, for the local production of active chlorine through the electrolysis of salted water. The resulting solution can be used for drinking water chlorination or as a disinfectant for use in households, hospitals or community clinics.
Specifically designed for the needs of developing countries, these devices give even the poorest of the poor an affordable to produce their own drinking water. Antenna Technologies is actively implementing various WATASOL programmes in the world.
The product line of WATA devices
includes three different models: Mini-WATA,
WATA and Maxi-WATA. These
cater to the needs of water treatment at various levels, from a small
group of households or a small village, to towns and settlements of
tens of thousands of inhabitants.
How the WATA device works
A WATA device requires water, salt and electricity. When immersed, and connected to a reliable source of electricity, a process of electrolysis takes place, converting the saline solution (sodium chloride) - with 25 grams of salt per litre - into active chlorine (sodium hypochlorite).
The WATA devices do not produce potable water directly. In fact, every litre of the active chlorine solution is enough, by dilution, for the chlorination of an average 4,000 litres of water.
Despite its simplicity, producing potable water for a community with a WATA device is quite a responsibility, and thus requires skilled people as operators, specially trained for that purpose. This Website features all necessary documents for specific training on the production and use of active chlorine, and it will be expanded to include multimedia training guides.
Water quality
It is important to have clear water, both for the process of electrolysis and the water to be treated with the active chlorine solution. Chlorination cannot be guaranteed if the water is cloudy or muddy. In such cases, it is necessary to first filter the water, or allow the sediment to settle or flocculate.
Life span of WATA device
All three models of the Watasol device are guaranteed for a minimum of 20,000 hours of operation (4.5 years, on the basis of 12 hours use per day). In practice, when used properly and cleaned regularly, their operational life span will be considerably longer.
Shelf life of active chlorine
An active chlorine concentrate must therefore be stored in opaque receptacles, properly closed and away from the light. When this is done, for the first three weeks after production, the average loss of chlorine is 0.16° per week. From the fourth week onwards, it is 0.35° per week. It is therefore advisable to use the chlorine solution within the first three or, at most, four weeks after production. Note that a full receptacle will keep longer than a half-empty one, where the air will oxidise the concentrate.
In order to measure the chlorine concentration in a chlorine solution, Antenna Technologies has developed the natural and non-toxic WataTest reagent