Almost 700 million people worldwide do not have access to an improved water source, and 1.2 billion people simply do not have any drinking water at all. What can be done for them? Since 2010, a Swiss company has been developing an innovative water treatment technology based on research and inventions by the French electrochemist Jean-Marie Fresnel. The interchangeability of the modules that make up this mobile, '"green" turnkey system means that it could also be used at environmentally-friendly mini water treatment plants.
WHO standard achieved
"We've designed a machine that can purify almost any surface water", explains Jean-Marc Rogivue, co-founder of Bühler Electricité Monthey (BEM) and its spin-off, NVTerra. An electrolysis process plus salt and iron make it possible to produce a disinfectant (sodium hypochlorite) and a coagulant (Ferilec) to eliminate phosphates, nitrates and heavy metals from water. Sterilisation or disinfection alone is not always sufficient to make water drinkable, so these toxic substances must also be removed from it.
In this way, almost all water can be brought up to the standard of treatment recommended by the World Health Organisation (WHO). The special feature of the process lies in the preliminary treatment: water can subsequently be treated using techniques such as ultrafiltration or reverse osmosis. The production of reagents in situ is a decisive factor for the rest of the purification processes, in particular because it prevents the filters from becoming clogged.
The company's aim is to produce 30 litres of drinking water per person per day in communities with between 1000 and 10,000 inhabitants.
In addition, all the machines are fitted with a system that enables them to be monitored remotely: the pilot unit at Addah, in Côte d’Ivoire, is monitored from Switzerland.
The technology is also intended for use as a complementary physico-chemical and biological treatment at the outflow from small water treatment plants, for example at the outflow from planted filters (the phyto-purification system used in environmentally-friendly mini water treatment plants). In this situation, the technology known as NVSani could offer an alternative to standard treatment systems that use harsh chemicals such as iron chloride (FeCl3), which is used in the majority of water treatment plants. Up to 1000m3 of waste water could be treated in this way every day.
After major R&D work during the last three years, NVTerra is going to continue the development of its project in Côte d’Ivoire and establish itself in North Africa and in France. Trials carried out in Morocco for four months in 2015 are likely to result in a tender proposal for two villages in the Atlas Mountains. The company is planning to carry out tests in France in 2017, in relation to tertiary treatment (elimination of micro-pollutants) and planted filter systems (environmentally-friendly mini water treatment plants).