This Severe drought situation in Catalonia In addition to severe restrictions on maintaining the population supply, it causes intense debate over the use of this resource. Scientists sounded the alarm: “We have to reformulate our water consumption model because the current model is unsustainable.“.
This increasing water demand And diminishing materials they exacerbate famines in many parts of the world. traditional approaches based on precipitation in water-scarce areas and runoff from rivers, anda is not enough to meet human demands.
unconventional water sources, such as desalinationcan play an important role in closing the gap between water supply and demand. However, desalination water involves a large discharge into the sea of hypersaline concentrate (brine), which is very expensive and requires disposal associated with waste. negative environmental effects.
A study by scientists from Canada, the Netherlands and South Korea in 2019 revealed that they existed in the world at that time. 15,906 desalination plants in operation (close to 800 in Spain) produces around 142 million cubic meters of desalinated water for human use every day, 48% of which is in the Middle East and North Africa region.
Writers, “best saltwater management strategies“Limiting adverse environmental impacts and reducing the economic cost of their disposal.
Serious impact on marine flora
This ecologists They openly question the most common water purification model. They do not reject desalination plants because they recognize that there are situations where it is necessary as it is the only and last measure to be taken. But they demand that they be used inside. renewable energys, because they are big energy consumers.
In any case, they argue that the way should be another no: increase water savings and rationalization of resourcesAs Greenpeace has demanded for decades.
Return of untreated brackish waters to the sea with high salinity, serious impact on aquatic vegetationespecially oceanic posidoniaEcologists emphasize that it is a vital species for the marine ecosystem, as it slows the erosion of beaches and helps maintain the biological balance of the waters.
In addition to the damage it causes to the marine flora, high energy consumption required for desalination plants. The Center for Ecological Research and Forestry Practices (CREAF) of the Autonomous University of Barcelona warned about all these issues.
For example, Catalonia has two desalination plants supplying 80 cubic meters per year to the Aigües-Ter-Llobregat feed system, less (20 Hm3/year) to Tordera and more (60 Hm3/year) to Llobregat. . CREAF.
“Over the next five years, 250 million euros are expected to be allocated for the expansion of Tordera and the creation of a new one on the Foix river with a capacity of 20 Hm3/year at a cost of hundreds of millions of euros. CREAF, which gathered the opinion of the institution’s water management expert Annelies Broekman’ “We will reach a total potential capacity of 140 Hm3/year,” says biologist Anna Ramon, head of communications.
High energy consumption
In addition to its economic costs, desalinated water “a huge environmental cost“, Since energy consumption Although it has fallen a lot since its first installations in the seventies, it is still very high. “Also, this consumption, produces emissions to the atmospheresign.
Another important aspect to consider is the construction of the facility itself, as well as the “New and expensive” infrastructure to transport desalinated water to areas where it is needed CREAF says infrastructures “have a limited technical life and require maintenance.” “This water has a huge environmental cost, first of all, due to the energy consumption required to carry out the process, although it has dropped a lot from about 8kWh/m3 at 2 3kWh since the first installations in the 70s/m3 in most optimized systems, On average, it still consumes about 4 kWh/m3 today.“, To add.
By comparison, a seawater desalination plant with a minimum output of 1.5 hm3/day consumes as much as 639,000 homes; population of more than one million According to estimates by CREAF researcher Annelies Broekmann. In general, it is assumed that a house consumes an average of 3,847 Kw/h of electricity per year.
Objections to purified water
On the other hand, it doesn’t seem like a solution beyond the specific, replenish the water from treatment plants for industrial, municipal or agricultural uses. The reasons are the same as in the case of desalination: high treatment cost and environmental impact.
“When not recycled, the treated water returns to the river, feeding circulating streams and contributing to the recovery of the river ecosystem,” says CREAF. “What if we recycle all the water instead of giving it back to the river? Flows decrease and we lose the life and normal functioning of some rivers.” To explain.
Desalination and water regeneration are therefore “useful technological solutions in the short term to deal with punctual droughtshowever, it is unsustainable over time due to its economic, energetic and environmental costs”, concludes CREAF.
So what is the solution? “The most urgent, the most intelligent, is to curb this insatiable thirst. braking request and be aware of the socioeconomic model we maintain above our means,” according to the center.Reflect the agricultural, urban, tourist and industrial model to reduce the total amount of water we use“.
Nature is the solution
“Use the water that allows us maintaining natural cycles and first of all replace the chip: Transition from wanting to meet all demands to prioritizing the protection of the health of water bodies and natural ecosystemsSeeing the solution in nature, CREAF points to eight keys to reach its goal of reducing consumption to predictable levels.
1 careprotect and restore natural water sources, rivers and aquifers.
dedicate 2 resources for decontaminating aquifers.
3 leave filling stream or drainage gaps with cement.
4 leave channeling rivers and changing channels.
5 chases illegal wells that extract water beyond the limits of permissible use.
reduce 6 widespread overuse of aquifers.
save 7 stream environment and river beds.
think 8 in-depth about the strategy of building more swamps or locks that cause a significant environmental impact as they interrupt the flow of the river.
business version
What does the Spanish Association for Desalination and Reuse (AEDyR) say? However, he claims There is no specific community or state regulation in Spain that regulates the discharge of salt water. imposes critical limits on desalination plants or chemical constituents and physical properties, if any. obligation to be subject to an environmental assessment procedure plants with more than 3,000 cubic meters of new or additional volume per day.
After this association submitted the environmental work to the claims, environmental impact statement (DIA), which specifies “conditions that must be met for sufficient” environmental protection and natural resources during the construction and operation of the facility”.
It is also a tool for pouring salt water into the marine environment. evacuation permit of the competent authority to which it will be carried out, which usually regulates a larger regulation. number of pollutants and specifies the unloading conditions and how sampling should be carried out in more detail.
In addition, projects for the use of desalination plants should include: comprehensive environmental monitoring program to protect sensitive areas from the extreme salinity produced by salt water spills. AEDyR explains that the priority is to protect ocean posidonia.
“Effective monitoring of all environmental studies, both before the construction of desalination plants on which the design of discharge systems depends, and during the operation phase of the plant, minimizing the effects of desalination on the marine environmentshowing that slight increases in salinity may occur temporarily and they are in very local extensions very close to the spill, Without affecting Posidonia oceanica meadows or other species‘ says the association.
Reference article: https://blog.creaf.cat/es/noticies/agua-sequia-permanente-restricciones-cataluna/
AEDyR website: https://aedyr.com/
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Contact address of the environment department: [email protected]