At last a more feasible less costly system to provide water for peoples living in arid zones with poor water supplies. The latest 3.2 version of the Warka Water system is being tested in Ethiopia as the last phase of a 5 year development programme in Italy and Ethiopia. The project was the winner of the 2016 World Design Impact Prize awarded by the International Council of Societies of Industrial Design (Icsid). Italian founder and architect Arturo Vittori leads a multidiciplinary team based in Italy, India, Lebanon, US, UK, Ethiopia and Nigeria.

Documento1Essentially, the Warka Water tower wighing 80 kg is 9.5m tall and diameter 3.7m at the base, can collect an annual average of 50 – 100 litres of condensation water/day with storage capacity of 3000 litres. It costs approximately Euro 900 when constructed in Ethiopia from locally available materials and labour and simple tools. The materials used plastic are biodegredable.

The water can be used for drinking, irrigation of essential food crops and for reforestation and regeneration of local ecosystems. At village level it offers independance from the laborious daily routine of carrying water long distances. Importantly the tower cab be managed (and probably owned) by the local people.

The collecting tower is light and modular so that it can be easily transported. No power is required and new filters and repairs of the collecting net are the only maintenance needs. The project also intends to train local villages to use the system and to establish water management programs that teach best practices of using, distributing and recycling the harvested water.

The project seeks crowd funding to reach about Euro 135,000 to permit the start of large scale manufacture of components and to cover some of the costs of initial supervision and training. For more information, consult the website. See: video: Warka Water Video


If there is one recent innovation that World Aid Organizations should be looking at, it is the WATLY device. This technology offers a global revolution for people in many countries of the world, deprived of clean water, electricity and telecommunications. It has the potential to provide small townships and millions of people throughout the world, the possibility of INDEPENDENCE and DEVELOPMENT because it addresses main problem issues: clean water, electricity and telecommunications all-in-one.

BUT the availability and provision of clean water is first and foremost a political hot potato because it lies at the source of life and food, therefore it carries the potential power to be exploited, political or criminal as it may be. Buyers will need to sell the services of a Watly unit to the people who use it. Where a Watly unit is provided as part of a foreign aid project, the way in which its services are provided to the local people will require close monitoring. Innovative technology is vital but the challenge facing its successful use, concerns organization, enforcement and maintenance to reduce expoitation to the minimum.

In many cases, the Watly technology and subsequent developments should be considered as a long-term substitute for food aid, that could be slowly phased out in parallel with agricultural support and the assisted purchase of Watly units by local townships promoted by local governments in alliance with World Aid Organizations, except for emercency provision. More information: Watly Web.

By the end of 2016 the sale of 10 Watly units pre-ordered from: Arab Emirates, Saudia Arabia, Jordan, Nigeria and Senegal, the cost of each unit should fall to around Euro 400.000 or about Euro 25.000/year when spread over a period of about 15 years also taking into account future economy of scale in manufacturing. Crowd funding is still sought to continue further developments. From the design stage, Watly received Euro 2 million from the EU Commission as part of the Horizon 2020 program. The administrative and marketing headquarters is located near Barcelona, Spain, and the manufacturing unit is at Talmassons, Udine, Italy.

Marco Attisani (centre) and some of the teamMarco Attisani and some of the team

Using solar energy, the Watly device (Watly is an acronym from water and lively) can produce clean water from any source of contamination, physical, chemical and bacterial. It can therefore deal with industrial waste, sewage, contaminiated wells, polluted rivers and lakes and desalinates seawater. More needs to be said by the Company about the ecological disposal of the resulting waste.

Additionally, the photovoltaic panels of each Watly unit provide up to 150 kWh of electricity each day, stored in batteries. Multiple electric chargers are provided for mobile telephones and other devices.  Also inbuilt is a telecommunications hub connected to the Internet. This will enable data collection and distribution and could extend to things like 3D printing and construction.

Size of the Watly unitThe units are easy to use and there are no filters or membranes involved so interventions for maintenance are low. Each stand-alone unit is prefabricated and can be assembled in less than 4 days. They are 40m long and 15m wide, weighing 15 tons, and function independently of electricity. They can provide for the needs of up to 3000 people and have a long guaranteed working life. With 2 or more units a network can be established.

Solar distillation technologyThe Italian creator of the Watly device, Marco Attisani, prefers to describe the system as a thermodynamic computer  See also Watly device, Spanish

References: Article in Italian by Angela Garbelli “Depurare l’acqua con il sole”, Article in Italian infoSOStenibile Number 53, June 2016, p35. InfoSOStenibile
Various presentations:

Vimeo 1

Vimeo 2

Vimeo 3

YouTube 4

YouTube 5

Dealing with Brine

One of the biggest problems with desalination plants is the return to the sea of highly concentrated brine. Where this mixes with coastal waters it can seriously damage the ecological balance.

Recent work by Dr. Philip Davies at Aston University in Birmingham, UK, proposes a system where the magnesium chloride in waste brine is hydolysed to magnesium oxide then discharged to the sea. For further information: P.A. Davies, Solar thermal decomposition of desalination brine for carbon dioxide removal and neutralization of ocean acidity. Environmental Science: Water Research & Technology. DOI:10.1039/C4EW00058G

Portable solar cells for purifying water in developing countries

Kenneth M. Persson, Professor of Water Resources Engineering at Lund University, Sweden, has developed portable water purifications units called Micro Production Centres. The patented technology combines UV-LED technology with intelligent software and WiFi. The system runs of just one solar panel that also charges a battery that allows the system to run 24 hrs round the clock in places where there is no electricity. Environmental Company Watersprint AB already has a contract with the United nations to place several hundred units in Bangladesh. For more detailed information from Lund University from from: Open Science


Crowd funding is sought by a group of technicians and designers to manufacture the Desolenator that is a small portable piece of equipment said to be capable of producing a large quantity of drinking water each day from salt and contaminated water through solar distillation. Desolenator See article:

20141203211508-desolparts2The Company resides at Bessemer Building, Level 2, Imperial College London, SW7 2AZ, UK, CEO: William Janssen.

More efficient technology

According to the World Health Organization, about 20 percent of the world’s people live in regions that don’t have enough water for their needs. With the global population increasing by 80 million each year, a third of the planet are likely to face water shortages by 2025. This looming crisis is inextricably linked to food production because agriculture accounts for 70 percent of all fresh water used. Obtaining irrigation water in arid regions has serious environmental impacts; drilling wells can deplete groundwater and desalination is energy-intensive and leaves behind concentrated brine.

Quite recently a team at Venice University, led by Dr. Paolo Franceschetti, have developed a more efficient solar distillation system that operates in total independence from other energy sources. This technology was awarded the National Prize for Italian Inventions in November 2011 at Torino.

Paolo Franceschetti and prototype            OLYMPUS DIGITAL CAMERA

Paolo Franceschetti (above) is CEO of Solwa Srl that is developing the technology, located at the Vega Science Park, Marghera, one of the most successful in Europe in terms of successful company

Q.1 What are the main merits of this solar distillation technology?

The new system is independent and modular and considered ‘mobile’. Essentially, it can used to provide pure drinking water utilizing seawater or polluted water. In tropical and equatorial regions, a unit of just 1m2 can produce up to 10 litres of drinking water/day, utilizing about 20 litres of seawater in the process. For each m2 of this system, solar energy is used to supply energy for the fan to draw water vapour to the heat exchangers and pumps.

Q.2 What developments are foreseen for this technology?

It should be possible to utilize the Solwa system to provide irrigation water for open-field crops of high value, utilizing drip irrigation and controlled irrigation regimes (partial root-zone drying comes to mind). The precise level of desalination can be tailored to the tolerance of given plants to salt and the type and location of cultivation. Soils can however be easily destroyed by the gradual build up of salt. Picture below: further developments of prototype in Palestine for the desalination of seawater.


The Solwa technology is also being adapted for use in greenhouse production. Through a project financed by the Italian Ministry of Defence, in collaboration with Consorzio S3Log, the Company will start experiments early in 2013, designed to realize a greenhouse model for agricultural production that uses only solar energy and desalinates seawater for the purposes of irrigation.

Trials with the Solwa prototype also suggest the same technology can be used in the conservation of food, drying fruits and reducing the weight and volume of waste sludge (organic and inorganic material) before transport to landfill or other disposal sites. The technology, appropriately adapted, can be considerably more cost effective than traditional methods. See: Introduction to Solwa technology pdf (English) and Introduzione alla tecnologia Solwa (Italiano)

Q.3 How does the system operate?

Essentially, seawater (or polluted water from a river or bore-hole for instance) is pumped into a heat exchanger where it is warmed by the flow of hot water vapor sucked out from the solar distillation unit. The now warmed seawater flows into a second heat exchanger, further heated by the super-saturated water coming from the distillation unit, this time to a temperature of about 60°C. This water then enters the solar unit where it is further heated by the sun’s energy to the point of evaporation. This water vapor is then extracted by a fan and flows into the first heat exchanger. The cycle repeats itself while pure water exits into a container. The energy required for the pumps and fan are totally met by a solar panel that forms an integral part of the system. The technology is covered by appropriate patents.

Q.4 What can be done with the discharge water?

Desalination is not continued to the point where salt crystalizes and accumulates as a solid that needs removing but the exit water super-saturated with salt (brine) needs to be discharged somewhere. This is a substantial problem. See:

In the case of large desalination plants, brine is normally discharged through a pipeline far out to sea in deep water so as not to disrupt the delicate coastal ecosystems and many countries are now adopting severe regulations in this regard.

Alternatively the brine could be used to salt fish or to produce salt for local consumption. It could also be pumped  to an alternative energy producing system that uses saturated salt solution*. The Solwa technology might also be adapted to sea going boats and ships, since the brine could be discharged directly to the open sea.

*Seawater/saturated salt solution and fresh water are separated by a membrane. The salt solution draws the fresh water through the membrane by osmosis, increasing the pressure on the side of the salt water. The increased pressure is used to produce power.  The world’s first osmotic power plant was built in Norway in 2009.

After making a few calculations, the quantity of irrigation water that the system can provide for a given area of production, should make it cost effective in sunny coastal areas where there is a shortage of fresh water or in sunny regions where the water supply is heavily contaminated. In the latter case the now more concentrated contaminants are duly collected and treated, the process of separation contributing to the depuration of the environment.

The system is totally sustainable because it uses no energy other than the sun and is relatively simple to construct and operate. This contrasts with the pollution factor and great energy consumption of reverse-osmosis desalination plants not to mention the very high costs of installation.

See the following attachments:

Brochure IDEASS (English) pdf    Brochure IDEASS (Spanish) pdf

Solwa presentation pptx

Edward Bent ©2012 | HORTCOM



  1. Pingback: Solwa desalination for horticulture | hortcom

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