WATASOL

A study published in January 2008 by the UNICEF shows that household-based interventions were about twice as effective in preventing diarrhoeal disease (47%) than improved wells, boreholes and communal stand pipes (27%). It is thus fundamental to find solution to enable population address their drinking water problem in a self-sufficient and perennial way. Aware of the need to introduce simple and affordable water treatment methods at household level, Antenna Technologies has developed a line of WATA devices (Mini, Standard and Maxi WATA), part of the WATASOL approach. Until today the WATA kits have been implemented in over 45 countries.

The WATA Devices

WATA is a handy and robust device for the local production of active chlorine through the electrolysis of salted water. The resulting solution can be used for drinking water chlorination (1 L of chlorine per 4.000 L of contaminated water) or disinfection of food preparation materials, premises and other equipment. Based on 12 hours of daily operation, Mini WATA can serve 240 individuals, Standard WATA 2.400, and Maxi WATA 36.000.

The 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 g of salt per litre - into active chlorine (sodium hypochlorite) at 6g/L. Water, which is possibly contaminated can be made potable by adding a small dose of chlorine (5 mL chlorine into 20 L water). The strong oxidising power of the chlorine will destroy most of the pathogenic germs. The water will be drinkable after 30 minutes.

The active chlorine concentrate solution produced with WATA devices can also be used as a disinfectant. In diluted form, it can be used for cleaning latrines, disinfecting kitchen utensils and surfaces, or even washing rough fruits and vegetables. It can also be used for disinfecting laboratory equipment. The concentrate is similar to Dakin’s solution, a neutral disinfectant, and can be used directly for cleaning wounds.

WataTest™ and WataBlue™ reagents are part of the WATA kits and allow the user simple onsite water quality control. WataTest™ is a non-toxic and inexpensive reagent, which is used to control the concentration of sodium hypochlorite in the produced solutions form the WATA devices. WataBlue™ measures the concentration of residual free chlorine in the water. Residual chlorine keeps the water pathogen free after disinfection. Minimal residual chlorine should be at least 0.5 ppm in order to prevent regrowth of the pathogens. But the chlorine should be below 1 ppm. WataBlueTM allows the user to carry out a safe and systematic quality control of the treated drinking water.

Costs

Specifically designed for the needs of developing countries, these devices give even the poorest of the poor an affordable solution to produce their own drinking water. Without the initial investment, the cost price for one litre of active chlorine concentrate is below € 0,01. Excluding shipping, investment costs for the Mini WATA are € 40, Standard WATA € 200, and Maxi WATA € 1.700.

Operation and Maintenance

Active chlorine is very sensitive to light. It is therefore very important to store the solution produced with the WATA devices in closed and opaque recipients, and to keep them in the shade. Under these conditions, the active chlorine concentrate can be conserved over 4 weeks without any problem. 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 settle or flocculate suspended solids. Devices need to be rinsed after each procedure with clear water. With time, calcareous deposits form on the electrodes. The frequency of which this deposits need to be cleaned depends on the water hardness, it is recommended to do it after about 150 hours of functioning. The deposits for the Mini and Standard WATA can be removed as follows: 1) Fill a recipient with lemon juice or vinegar; 2) Immerse the WATA device overnight into the lemon juice / vinegar – Do not scrub; 3) Rinse the device with clear water, dry it and store it. WATA maxi calls for different procedures.

Properly used, well maintained and carefully stored after each use, WATA devices are guaranteed to operate for at least 20 000 hours of operation (4,5 years on the basis of 12 hours use per day).

The WATASOL Approach

WATASOL is more than a device; it is an approach, which integrates health education with the local production of chlorine in a sustainable supply chain, making safe water treatment a profitable activity. In the long term, the production and the dissemination of chlorine should generate an income for the local population and should insure their autonomy. Several dissemination models have been identified and tested in the field:

• Through health centre: they produce their own disinfectant (Dakin solution) at very low cost;
• Through economical structure (i.e. women’s groups, salesperson in kiosks): they create an income-generating activity around the production of chlorine;
• Through school structures responsible for promotional and awareness activities;
• Through water user association.

The WATASOL approach can be introduced by organisations step by step:

1. The Demo phase helps getting people familiar with the Watasol technology;
2. The Try-out phase gives hands-on familiarity;
3. The Testing phase confirms the viability of local production of chlorine;
4. The Pilot phase will determine the right dissemination strategy and potential business model;
5. The Scaling-up phase aims to replicate successes on a wide scale.