Calvenzano melons are large, weighing in at 2-5kg (the record is 6kg) elongated with a strongly netted exterior or rind, and crisp, orange flesh. Calvenzano is a small town in
Water, water, everywhere, nor any drop to drink. (S.T. Coleridge – The Rhyme of the Ancient Mariner)
We know that at least 70% of all clean fresh water is consumed in irrigating agricultural crops. With the growing world population and requirement for more food, and the increasingly uncertain rainfall due to climate change, the availability of irrigation and drinking water is increasigly under pressure. In this section, innovation (especially disruptive innovation) is placed under the headings: PRODUCTION (desalination – solar distillation), COLLECTION (condensation water) and ERROGATION (irrigation).
In some cases the innovative technology presented is intermediate in nature but because of its clever design, cheapness and simplicity, it wins over larger more sophisticated systems, especially at the level of local village life in developing countries. This is the case with the collection system WARKA WATER. The same applies to smaller, portable systems of solar distillation adaptable also for townships.
A larger, more complex and expensive system to produce clean water is represented by the WATLY system, the prototype capable of producting 5000 litres per day. One of the first innovations to produce clean water for drinking and irrigating crops was the SEAWATER GREENHOUSE. Subsequent developments, adding CSP (concentrated solar power) technology were incorporated in horticultural production plants exemplified by SUNDROP FARMS in Australia and the pilot plant in Quatar part of the SAHARA FOREST PROJECT. Last but not least the SOLWA solar distillation system has been engineered primarily to produce clean water or essicate fruit and vegetables or biological sludge.
HORTCOM would also like to present new products and systems that errogate water for agricultural and horticultural crops, but only those that represent disruptive innovation (i.e. completely new thinking rather that further developments of existing products). Please contact the authors.
WATER COLLECTION: CONDENSATION
A highly practical and economic system to provide water for local villages 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. 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, Nigeria, Togo, Haiti, Brazil and Colombia. www.warkawater.org
The Warka Water tower weighing 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. Photovoltaic pannels to generate electricity can also be attached to the tower which also spawns other notable advantages to village life, namely toilet facilities and composting that converge to provide fertile, irrigated areas for growing food and for reforestation. At village level it offers independance from the laborious daily routine of carrying water long distances. Importantly the tower can 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 is working to start 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
SOLAR DISTILLATION SYSTEMS
A Watly World. If there is one 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. Watly Web.
BUT at this larger dimension, water is also politics. The availability and provision of clean water for townships carries potential to exploit local consumers economically and politically by local government and ‘big daddies’. Because of the heavy investment costs, buyers will need to sell the services of Watly units 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, requires constant vigilance and enforcement to reduce eventual expoitation.
In many cases, the Watly technology and subsequent developments could 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.
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/brine.
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.
The prototype plant is heavy and cost some €2.5 million to build mostly financed by the EU Commission’s Horizon 2020 program. Future developments envisage larger units capable of producing 10,000 litres of clean water per day. Once production is increased the cost of each unit should fall to around €400,000 or about €25,000/year spread over 15 years. Tests are being made in Ghana and pre-orders have been made with: Arab Emirates, Saudia Arabia, Jordan, Nig
eria and Senegal. The administrative and marketing headquarters is located near Barcelona, Spain, and the manufacturing unit is at Talmassons, Udine, Italy. See Watly events.
The 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.
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
Seawater Greenhouse – Evaporative cooling.
The Seawater Greenhouse heralded the beginning of a new way of utilizing seawater and sunshine, abundant in various parts of the world, to produce fresh water, energy and food. On
talking to Charlie Paton, CEO and inventor, it became clear that the take-up of this straightforward and relatively innexpensive technology is hindered by politics. Essentially the SG is a hybrid between a mini-desalination plant and a greenhouse; it desalinates seawater, providing fresh water for the greenhouse cultivation of plants and a small surpluss for local distribution. A prototype was built many years ago on Tenerife, Canary Islands, an ideal location given its high solar radiation, strong prevailing winds and deep, cold seawater. www.seawatergreenhouse.com Despite successful trials and support from local farmers that wanted to promote its use, the SG was deemed by the EU to undermine the CAP (Common Agricultural Policy). Local politics had also changed, encouraging rapid development of the tourist industry at the expense of agriculture. Many farms located on prime coastal land were compulsorily purchased by government for tourist development. The production of desalinated water under-pinned this development and today the Canaries are heavily reliant on large desalination plants that burn fossil fuels and pollute the environment.
The inventors claim that the SG produces a surplus of fresh water for the local distribution system, up to 5 times the amount required for irrigation of the crops themselves. This might not be much, individually, but the multiplying effect of many SG’s could make a considerable contribution. Alternatively large state-of-the-art SG’s could produce high value crops. Operating costs are said to be much lower than for ordinary greenhouse production and plants require less irrigation water. Cheaper land can be utilized where ground water is unusable or absent. Neither is the SG considered by the ITC (Canary Islands Institute of Technology) in its research to develop small stand-alone desalination plants that utilize renewable energy and provide enough fresh water for a few hundred families. If these claims are true, why has the SG technology not been considered by local authorities and private developers?
Q1. What are the costs and economics of employing the seawater greenhouse technology?
The Seawater Greenhouse is today a proven technology although it has not yet realized its potential in those areas of the world most indicated. Design specifications vary according to climatic conditions, grower requirements, irrigation system, local materials and labour. Greenhouse cladding can be polythene, rigid plastic or glass. This means that the cost of installation is variable from USD50 – 150/m2. Average comparisons between the operation of a 2ha unit of Seawater Greenhouse indicates a potential reduction of fixed costs of 10-15%, lower operating costs of 10-25% and improved returns of 15-35% against a traditional greenhouse of the same size (clad in plastic or glass). A thermodynamic model is used to predict the most effective solution.
Q2. What are the evaporative cooling principles behind the Seawater Greenhouse?
Essentially, a fan draws hot dry air from the outside across an evaporator set into one of the outside walls of the greenhouse. Surface seawater is pumped to the top of the evaporator and trickles down its mesh surface. In the process the air is cooled and humidified. It is also filtered from salt spray, dust, insects and pollen before entering the greenhouse. The seawater is then channelled through a pipe at ground level to a second evaporator.
Hot dry air from between two layers of the roof (the lower layer being a partial screen) is pulled in by a fan and pushed in by the prevailing wind towards a second evaporator. The meeting of cooler, humid air with the hot, dry upper air increases its ability to absorb moisture before reaching the second evaporator, where it picks up more water vapor to the saturation point. Pure water then condenses onto the cold surface of the condenser. This is collected and passed to a storage tank for use as irrigation water for the plants or for drinking purposes. Other crops such as fruit trees (or Jatropha for biodiesel) can be grown in the outside now more humid air at the other end of the Seawater Greenhouse.
Under these warm humid greenhouse conditions, plants grow very quickly and their demand for water therefore drops. In the prototype this fell to 1 litre/day/m2, compared to 8 litres/day/m2 in conventional protected cultivation. Solar panels power pumps and fans. A Seawater Greenhouses have been built in Somaliland and others are planned in the Caribbean region after successful trials in Tenerife, Abu Dhabi and Oman. www.seawatergreenhouse.com
Since the incoming air is filtered and sterilised, biological production can be more easily achieved with the SG and by using soilless cultivation systems cheap degraded land is sufficient. It also opens up the possibility of producing all-year-round food crops and drinking water in some of the world’s hottest and driest regions, especially along coastal regions.
Q3. What are the latest international developments?
Seawater Greenhouses designed by researchers at Aston University has been constructed on the coast in Somaliland (near Berbera 2017) to grow crops in one of the hottest and driest places on earth, working with industry partners as part of an international project. Extract from a Press Release from Ashton University 14th July 2015. See also article by Matt Hickman, April 12, 2018, entitled ‘Seawater Greenhouse brings agriculture to world’s harshest environments’. This £722k greenhouse project is funded by Innovate UK with support from the DFID: Department for International Development under the Agri-tech Catalyst Industrial Research strategy. The installations are to be erected in specially selected sites across the Horn of Africa, a region where temperatures regularly breach 40°C, water is scarce and food insecurity is very high.
The project aims to overcome the region’s inhospitable conditions to help farmers drastically increase their crop yields, providing them with a consistent, sustainable income. Currently in Somalia average annual crop yields per hectare are just 0.5 tons – compared to 700 tons per hectare in commercial greenhouses.
The productivity and quality of crops cultivated in greenhouses is typically much improved upon traditional open field cultivation and the use of water and nutrients is much more economical. Once installed, the innovative greenhouses will pump seawater from the sea using solar energy and convert it into freshwater for irrigation via the desalination process. The remaining seawater will be brought into contact with the air inside the low-cost net structures of the greenhouses, creating a cool and humid breeze to reduce plant transpiration. Salt extracted from the seawater will be utilised in cooking and preserving food.
A team from Aston, led by Dr Philip Davies and Dr Sotos Generalis, will provide their expertise in areas relating to seawater cooling, desalination of saline water and airflow dynamics, helping to design the structure and the layout of the greenhouses. They will collaborate on the project with fellow academics at Gollis University, in Somaliland, and the firm, Seawater Greenhouses Ltd that is leading the whole project.
For further media information, please contact Jon Garbett, Aston University Communications on 0121 204 4552 or email@example.com.
Concentrated solar power (CSP) together with evaporative cooling
In Port Augusta, Southern Australia, SUNDROP FARMS PTY LTD has become the world’s first fully commercial Seawater-cooled Greenhouse, significantly modified by using CSP technology (concentrated solar power) to create electricity. A 70m stretch of concave mirrors follow the sun and concentrate solar energy on thermal oil running along a tube heating it to 160°C. This oil is conducted to a heat exchanger. The resulting steam drives turbines that produce electricty. Sundrop Farms
The remaining brine from the desalination is conducted to ponds where ‘gourmet’ sea-salt and other minerals (such as Calcium, Potassium and Magnesium) are extracted for use in production or sold to other interests. Sea algae can also provide additional nutrients. Soilless cultivation (rockwool/hydroculture) is used and the greenhouse air is cooled and humidified by passing cool seawater over evaporative panels. This reduces the air temperature by up to 15°C compared to the outside. At the other end of the greenhouse water vapour is condensed. Some is used to irrigate the growing crop, part is harvested as drinking water, some is used for the steam turbine and to clean the array mirrors. Solar energy is used to power all other operations (heating and cooling) in the greenhouse. A diesel powered generator is required only for very short period in the winter to make up any shortfall. Sundrop System.
The Seawater Greenhouse/Sundrop pilot plant received a start-up grant from the (RDIF) Regional Development Infrastructure Fund from Southern Australia. This has already been significantly extended and is currently producing large quantities of tomatoes and sweet peppers. Further developments could move in the direction of adding algae and fish to the productive output. Sundrop Partners.
The capital costs of incorporating CSP technology into the system is very expensive and financial support is necessary. Thereafter, operating costs are reduced by 10-15%. In general terms, the higher the investment the greater the productivity and profitability. It is most suitable for hot, dry climates on low land near the sea and interest has been expressed from many countries, especially in the Middle East. See Video
Political decisions should try to utilize all available environmentally friendly technologies, matching these technologies with diverse local needs and possibilities of extraction and distribution of fresh water. Now that some desalination plants in the Canaries need replacing or that greater quantities of fresh water are needed, cannot the Seawater Greenhouse feature in future plans, perhaps alongside stand-alone technology being developed by the ITC (Canary Islands Institute of Technology)?
Usuing this technology to green desert coastlines
The Sahara Forest Project is a Norwegian private limited liability company for providing new environmental solutions to produce food, water and energy in desert areas. The Project combines proven technologies, including saltwater-cooled greenhouses, concentrated solar power (CSP) and technologies for desert revegetation around a saltwater infrastructure. The synergy from integrating the separate technologies into a system improves their individual performance and economics. The government of Jordan has also agreed to a direct future involvement in the project and Sundrop Farms Pty Ltd has signed a collaborative agreement with the consortium. Video Sahara Forest Project
In December 2012, the new 1ha Sahara Forest Project pilot facility (above picture*) near Doha, Qatar, realized by The Sahara Forest Project and partners Yara International Asa www.yara.com, Quafco (Quatar fertilizer Company) www.qafco.com, was venue for guests attending the COP18 (UN Climate Negotiations in Doha). On this occasion visitors were served the first cucumbers grown by the pilot facility. This facility also includes an extensive algae research centre. *Courtesy of Sahara Forest Project.
Increasing distuillation efficiency – SOLWA
A team of researchers at Venice University, led by Dr. Paolo Franceschetti, 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. Solwa World Paolo Franceschetti (above) is CEO of Solwa Srl that developed the technology at the Vega Science Park, Marghera, one of the most successful in Europe in terms of successful company start-ups.www.vegapark.ve.it
Q4. 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.5 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. Solwa, India pdf Solwa (Italiano) pdf
The Solwa technology has also been 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.
Solwa has engineered equipment using this technology for other important uses, including the essication of waste sludge (organic and inorganic material) thereby reducing weight and volume before transport to landfill or other disposal sites or inceneration. Similar the technology is being used to essicate fruits and vegetables. 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)
Q6. How does this 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.
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. www.solwa.it
Q7. What do you do with the super-saturated salt solution (brine) at the end of the process and is there no legislation to reduce this environmental pollution?
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. Importantly, instead of discharging super-saturated salt solution (brine) back into the sea, the Seawater Greenhouse can recover sea-salt and make it a sought-after, saleable product. The discharge of brine from the large desalination plants located around the world continue to seriously damage large areas of coastal ecosystems. In 2008 about 18.4 million m3/day of brine were discharged into the Arabian Gulf, 9.8 million m3/day into the Mediterranean and 6.8 m3/day into the Red Sea. The reduced inflow on fresh water from rivers such as the Euphrates, Tigris and Jordan worsens the situation.
Some countries now have strict legislation forcing desalination plants to construct long pipelines for discharging the brine far out to sea and not along the ecologically more sensitive coastal ecosystems. However, this is not enough to stop the increasing saline pollution of many of our seas. See: Global Water Forum 2012. http://www.globalwaterforum.org/2012/05/28/seawater-greenhouse-a-new-approach-to-restorative-agriculture
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 uncontaminated 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
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
Membrane technology (MEMSTILL). Researchers at Wageningen UR developed a more efficient membrane technology to produce drinking water when compared to reverse osmosis but the technology costs more. After saltwater is heated the water vapour is passed through a membrane that blocks the passage of salts and other contaminant that are then collected. The new MEMPOWER system generates electricity for the system. The fresh water produced under pressure in the Memstill system is used to drive a turbine. See further details from Wageningen
Portable Solar Cells. 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 (PT) already has a contract with the United nations to place several hundred units in Bangladesh. For more detailed information from Lund University
Desolenator is the name given to the equipment designed by a group of technicians needing further investment funding. It 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: www.indiegogo.com/projects/desolenator
The Company resides at Bessemer Building, Level 2, Imperial College London, SW7 2AZ, UK, CEO: William Janssen.
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