Off-grid water | Water world

Fresh drinking water can be something people often take for granted, but when it comes to a large African country – whose vast land area covers vast areas that differ greatly in their rainfall and sources of water. water – solutions for a regular supply of drinking water are becoming complex, difficult to implement and expensive.

Drought in Angola

Cunene is located in the southern province of Angola, in West Africa, bordering Namibia and characterized by extensive and arid territories. A prolonged drought in southern Angola has hit that province, affecting some 80 percent of the local population, including animals, who have died in large numbers due to lack of water.

Due to the severe drought the region has endured since 2018, it was recognized as a global disaster area and received national and international priority until in 2019 the President of Angola visited the region to assess and respond to the plight of its inhabitants. residents. The president visited a small village called Ombala yo Mungu, where he assured the locals that he would do his best to give the people and animals who live there a source of clean water.

Following the president’s visit, and on his instructions, the Angolan water ministry contacted a number of international companies to provide an urgent response to the water crisis in the region. Owini, a company of the international Mitrelli Group, rose to the challenge by visiting the village, located hundreds of kilometers from the populated areas. On site, the Mitrelli team conducted a field survey to understand the drinking water problem and develop a plan to provide the most appropriate solution for the village.

Following his initial investigation, Owini realized that there were two issues. First, there is no potable water in or around the area. In fact, there is only saline groundwater well below the surface. In addition, there is no energy available in the electric grid to operate the water supply systems, and the rural location of the region meant that it would be extremely difficult to establish a fuel supply for generators.

Owini carried out numerous water tests in the field, including those from old boreholes from the Portuguese period, finding brackish water below the surface. At this stage, the whole concept of the project has changed from the standard installation of a drinking water supply system to a brackish water desalination system; which posed a complex planning, logistical and economic challenge, in addition to the difficulty of operating and maintaining such a system in a remote and arid region.

Subsequently, Owini decided that a rapid desalination solution was needed, with independent capacity for energy production and storage. The facility should also include the ability to store water for several days in the event of a prolonged malfunction, until a technician can arrive, due to the remoteness of the village from more populated areas.

In addition, remote monitoring and control capabilities should be installed to allow receipt of information about malfunctions – and in many cases also their treatment – without the need to send a technician to the site.

The solution

The envisaged solution is an innovative water desalination system entirely based on solar energy, capable of conserving the energy produced during the day and allowing continuous operation 24 hours a day. It was also installed to provide water for a minimum of three working days, even without pumping, as professional repairs could require a three-day journey from Luanda, the capital of Angola.

The system includes two boreholes to create continuous flow, a container with desalination elements and batteries for energy storage / discharge, and solar panels for all operations. Drinking water is then channeled to an underground reservoir, which is enough to support the population for three days, with an independent pumping station also powered by solar energy.

The reverse osmosis water desalination process, in which the salts are separated from the water (in this case brackish groundwater) by means of a membrane, produces potable water, while the production of solar energy operates the desalination process.

The water is pushed under pressure from the pump to the reservoir, and from there to the drinking water points around the village. Photovoltaic panels absorb energy from the sun during the day, and deep cycle batteries store some of that energy for use during nighttime operation.

By combining desalination and solar energy, it is possible to provide good quality water to the inhabitants of a very remote neighborhood where there is no drinking water, regular electricity supply or sources of water. conventional energy.

In addition, it is possible to track the performance of the system through a remote control system and monitor its operation from Owini’s office in Israel.

Pandemic paralysis

The company faced many challenges – flooding that destroyed access roads, high salinity water, lack of energy sources – but most important of all was the coronavirus pandemic which crippled business international.

During this period, it was difficult to continue the planning and preparation work in the field, to produce the various containers and energy devices in Israel, to move the containers full of equipment from Israel to Angola, or to cross the ‘Angola without first obtaining special travel permits. and the work. Despite these challenges, good planning made it possible to execute the project to the client’s satisfaction.

The project was completed in November 2020 as planned. Drinking water that meets European health standards is now flowing to the village for the benefit of residents and their livestock. Government officials and local media come to visit, admiring the innovation and creativity of the project.

Following the great success of this project, and as a prototype project for remote areas without a source of fresh water, there is a desire to replicate it in other areas in Angola. In addition, Owini is using this project to demonstrate solutions for other countries where there are inhabited areas with extreme climatic characteristics, lack of available energy and scarce water sources.

The success of this village is part of a much larger project in Angola called “Water for All”. As the name suggests, its goal is to provide water and long-term sustainable solutions to global water needs, and to improve the standard of living and health of the local population. WW

About the author: Efi Beck is responsible for the development of the Owini Group at Mitrelli and has been with the company since 2012.

Posted in Water world review, December 2021.

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