The drought crisis is affecting practically all sectors in the internal basins of Catalonia, and swimming pools for recreational use are at the forefront of the debate on the use of water in emergency situations like the current one.
Companies specialized in pool maintenance are unable to supply these days due to the multitude of queries from owners and users about the immediate future of their facilities.
One of the most recent doubts is whether they can fully or partially fill their pools with seawater. This possibility has gained currency after some company not specialized in swimming pools has publicly offered its commercial services to transport seawater to the facilities that require it.
Companies in the component manufacturing, construction and maintenance sector of swimming pools; as well as the Catalan Water Agency (ACA), on the other hand, warn that the proposal to fill or refill swimming pools with seawater is technically very complex in the vast majority of cases and that, in addition, it may be illegal considering the current legal requirements.
In the technical part there are several aspects to take into account first. The vast majority of swimming pools in operation in our country are divided between those that use fresh water, to which chemicals such as chlorine are added to maintain healthy conditions, and swimming pools that have saline hydrolysis systems (electrolysis), that is, That is, they use slightly salty water (between 2 and 6 grams of salt per liter of water) with which they generate their own chlorine, with the same disinfectant objective as the chlorine added directly to freshwater pools.
Only a very small proportion of swimming pools have more sophisticated disinfection systems by treatment with ozone or ultraviolet light. In an even smaller number, there are some pools located very close to the coast in which sea water is used directly, which is captured and returned to the sea with the legally established permits and conditions.
For freshwater pools with added chlorine, the proposal to use seawater in whole or in part is completely unfeasible, agree the specialists in manufacturing and maintenance of this type of facilities consulted by La Vanguardia. Putting salt water in a freshwater pool disables the function of chlorine, damages filtering equipment and causes corrosion that can endanger the integrity of the entire pool, specialists say.
In the case of pools with saline hydrolysis, the incorporation of seawater is not recommended either. “If we partially fill the pool with seawater, we run the risk that the saline electrolysis equipment will stop working, since seawater contains 33 grams of salt per liter and the equipment works at 6 grams,” details Angel Pastor. , from the technical service of Piscines Blanes, one of the leading companies in the sector in Catalonia.
“Sea water can stop electrolysis and can damage equipment, in addition to increasing corrosion; Only in specially prepared pools, such as those for thalassotherapy treatments, can seawater be served safely,” explains David Trias, Director of Innovation at Fluida, one of the most important pool equipment manufacturers in the world.
In addition to the technical warning, the Catalan Water Agency (ACA), which has also received multiple queries on the matter in recent days, recalls that although theoretically seawater can be used in swimming pools, it is explicitly prohibited to discharge seawater both into the natural environment and to the sewer system. Therefore, if an owner or user of a swimming pool incorporates seawater into their installation, they will have to find their own system to manage its subsequent removal or even the pool water that is periodically used to clean the filters (which in the rest of the pools are discharged into the sewer).
This prohibition on the discharge of seawater into the sewer is general and aims to avoid the technical inconveniences that salt produces in wastewater sanitation facilities. Likewise, it is prohibited to discharge seawater into the terrestrial environment to avoid the salinization of land, surface and underground waters.
David Trias, from Fluidra, highlights that the ACA “is making a great effort in management and information in a situation as complex as the current one” and encourages citizens to collaborate in saving water, “and consult details about the drought in the ACA website, which is really good.”
