In 2040, Saudi Arabia will be the ninth country that will suffer most from water shortage in the world. Although far from the ideal ranking position, it is more comfortable than before, according to a World Resources Institute report. This is because, recently, the country decided to draw heavily upon alternative water treatment technologies, as desalinated seawater. As we know, our oceans cover more than 70% of the Earth's surface, but it is neither fresh nor fit for human consumption, which makes water shortage as serious as ironic. After all, we are the water planet, but most of it is unfit for our consumption.
Saudi Arabia is not the only country to face an upcoming water stress. According to the UN, world water resources will shrink 40% by 2030 while demand shall increase around 55% until 2050. Everyone will be affected. In this regard, desalination - increasingly common in countries with abundant energy and close to the sea - will only be a partial solution to the problem. Other nations, however, will have to resort to other tools to diversify their production of the resource. Nature itself can bring solutions, according to a UN report.
Betting on desalinization
In December 2015, the desalination plant in Ras al-Khair ramped up to full production; since then, it produces 1 billion liters of drinkable water daily, and now it is the world’s largest plant. That's enough to meet the basic daily needs of 9 million people, according to the UN. Before, the largest seawater desalination plant ever was in Tel Aviv, Israel, which produces about 624 million liters of drinking water daily. Israel is also among the 10 countries that most suffer - and should continue suffering - from water shortages.
The technology involved in most modern desalination processes does not stop improving. Today, reverse osmosis, one of the most efficient desalination techniques, involves pushing salt water at high pressure through a polymer membrane containing holes about a fifth of a nanometer in size, or 375,000 times thinner than a hair. The holes are small enough to block salt molecules but big enough to allow water molecules through. This is only made possible due to the technology that has advanced in recent times. Now, there are materials and pre-treatment techniques that keep the membranes working more efficiently for longer and with no clogging, as in the past.
Environmental impacts in desalinization
All current desalination processes require a great deal of energy to work. Although reverse osmosis is more energy efficient than the more traditional method of boiling and evaporating salt water to collect evaporated water as a pure distillate, it is still a process that requires a lot of energy. No wonder it is used on a large scale by countries with most energy reserves - often derived from oil. In this sense, there is environmental concern with its production and the environmental footprint it leaves behind.
One issue with desalination is what to do with the leftover salt. Floris van Straaten, from the firm overseeing construction of the Ras al-Khair project, explains to the BBC: “You have to make sure the very salty water is pushed away far enough into the sea so that you don't have recirculation of the water." Still according to the BBC, in the USA, some environmental groups have brought the construction of new desalination plants to courts, saying the consequences of reintroducing brine to the ocean have not been adequately studied. Another concern is that when water is drawn from the ocean, it brings fish and other organisms into the machinery.
Nature as an ally
During the World Water Forum, an event held in Brasília in March this year, the UN launched a report presenting nature-based solutions for water treatment. As the name says, these solutions use, or simulate, natural processes to address contemporary water-related challenges. The goals are to increase water availability (from retention of soil moisture and groundwater recharge, for example), to improve water quality (creation and preservation of natural and artificial wetlands and riparian buffers) and to reduce the risks associated with water-related disasters and climate change (through restoration of floodplains and vertical gardens).
That is, nature-based solutions are ecological processes largely driven by vegetation and soils in forests, grasslands and wetlands, as well as in agricultural and urban landscapes, which play an important role in the movement, storage and transformation of water.
The main point is that the report does not recognize water as an isolated element but as an integral part of a complex natural process involving evaporation, precipitation and absorption of water by the soil. The presence and extent of vegetation coverage - such as grasslands, wetlands and forests - influences the water cycle and can be the focus of actions to improve quality and quantity of available water.
Agriculture and water production
Globally, agriculture accounts for about 70% of water consumption, while industry accounts for 20% - including electricity generation - and domestic consumption, 10%. While agriculture is the largest consumer, it can also be the biggest ally in water production. By using concepts related to sustainable agriculture, farmers are able to increase water infiltration into the soil, for example, by enriching the water table, which has a positive impact on water production.
The Water Producer Program, a project of the Brazilian National Water Agency (ANA, in Portuguese), supports, guides and certifies practices aimed at reducing erosion and sedimentation of springs in rural areas – which is to say, these measures have an impact on water production and supply. Payment for Environmental Services (PES) was adopted for this project.
PES is used to encourage environmental service users or beneficiaries to turn into service providers through financial resources or otherwise. Today, according to ANA, the program has 57 projects in an area equivalent to 400,000 hectares. More than 2,000 farmers are paid for environmental services that impact around 35 million people in cities such as Rio de Janeiro, São Paulo, Brasília and Palmas, in Tocantins.
"We want to encourage good practices that enable water infiltration into the soil," says Devanir Garcia dos Santos, Coordinator of Inductive Projects Implementation at ANA, such as the Water Producer Program. "Today, we have short bursts of intense rainfall and our soil is almost waterproofed by activities such as agriculture and urbanization - that is, water is not reaching the water table, so we have little reserve down the soil," he says. "When you improve soil infiltration ability, much of the water that causes flooding will seep into this soil. Thus, you are producing water for economic activities," summarizes Santos.
The program identifies and guides a series of techniques that improve infiltration, including, but not limited to crop rotation, fertilization of grassland areas and management of livestock to avoid bare areas, in addition to breaking the ground to enable infiltration and construction of channels for water retention.
The role of the countryside and the forest
One way to produce water in the countryside is by conserving and preserving the few native vegetation of the basins. Reforesting parts in the recharge zone where water enters to feed the water table is also critical.
"Costa Rica is a good example of water production," Santos remembers. "They care way more about the forest - and if we could get back to more forest areas as before, it would be amazing to fight the shortage. Since this is not possible, we have other options," he says, referring to the Water Producer Program. "In Brazil, we are cutting-edge because we are transforming that area which produces only grain, milk and meat, into a water producer. The same space is used for water collection and infiltration," he explains.
In 2006, a study conducted by Embrapa drew attention to the expansion of urban centers, the intensification of industrialization and the expansion of irrigated agriculture. "The water, as rain, follows three paths: it evaporates, it drains superficially or it infiltrates into the ground. In the first case, it is incorporated into the atmosphere and can form clouds again. In the second, it increases the river flows, it flows through river courses to the oceans. In the third, it infiltrates under the surface or deep layers, thus enriching groundwater. Ultimately, the increase of water infiltration goes through vegetal covered areas of a contributing watershed,” the document affirms.
According to the analysis, the actions of integrated management of watersheds must transcend a purely agricultural approach. "Within this perspective, the rural space is relevant not only in the production of food and fiber, but also as a water producer in enough quantity and quality, for multiple uses by other segments of society," the authors of the study explain.
Countryside and city can contribute
According to Santos, from ANA, although the countryside is more suitable for measures to expand infiltration and water production, the cities can also contribute, even though largely waterproofed by cement. Some examples are the expansion of green areas and the creation of infiltration boxes in houses and apartments to collect water from the roof and direct it to non-waterproof soil.
"In addition to collecting water from the roof, there is also the reuse of gray waters, which is water from sinks and washing machines," he says. These types of water can be used to wash the car and the yard, for example, as well as indoor floors of wet areas such as the kitchen and laundry areas. Other good options include adapting the house, adjusting for an economic flushing system, or using a shower that mixes water with air.
It is key to make use of available resources in areas served by the water distribution network. Today, 37% of the treated water is lost in the distribution network, nor does it contribute to the fact that only 39% of the Brazilian sewage receives some treatment, while the rest goes straight to nature. It is clear, therefore, that the solutions for expansion and diversification of water production need to be thought widely, in order to take into account different aspects of the issue - the different realities in the countryside and cities, losses in distribution, waterproofing of the soil and, mainly, the obstacles in infiltrating and protecting the liquid.