Thursday, 7 August 2025, 17:31
The Costa del Sol was a pioneer in the use of reclaimed water after tertiary treatment in wastewater treatment plants (WWTPs). This is how golf courses began to be irrigated almost four decades ago, still using a rudimentary system. Currently, the WWTPs managed by Acosol can produce some 47 million cubic metres per year. However, only between seven and ten of those 47 are sold. Bureaucracy and sanitation-clearance permits hinder the development of a resource for which the infrastructure is well-prepared and for which there are already exacting health requirements in place.
Thus Acosol, the water company of the Mancomunidad de Municipios de la Costa del Sol Occidental (the alliance of 11 towns on the Western Costa del Sol to pool shared resources such as water) has put out to tender a technical assistance service valued at 51,000 euros that is to be developed over a total of three years. The first targets are more water for street-cleaning and gardens.
Acosol has been supplying reclaimed water since early 2003. In that year, Spain’s environment ministry granted a concession for water from the Guadalmansa WWTP in Estepona to be used for golf course irrigation. In 2008, the regional government’s environment ministry issued a permit for the reuse of treated wastewater from Arroyo de la Miel, Cerro del Águila, La Cala de Mijas, Arroyo de la Víbora and Manilva for golf course irrigation.
Permits
Subsequently, in 2024, in order to adapt to new regulatory requirements, Acosol began processing the various permits for the production and supply of reclaimed water at each of the wastewater treatment plants it manages and where it has tertiary systems for reuse. These are the plants at Arroyo de la Miel, Cerro del Águila, La Cala de Mijas, La Víbora and Guadalmansa. In turn, it has been commissioned by various municipalities belonging to the Mancomunidad to process applications for reclaimed water concessions for urban use.
The 11 municipalities involved are Torremolinos, Benalmádena, Mijas, Fuengirola, Marbella, Estepona, Manilva, Casares, Benahavís, Ojén and Istán.
Procedure
In both cases, permits for production and supply from WWTPs and reclaimed water concessions for urban use, it is necessary to draw up reclaimed water management plans to complement these procedures. The regulatory framework to be followed, as of the end of 2024, is the water reuse regulation published in Royal Decree 1085/2024.
The various treatment plants process reclaimed water for industrial, recreational or environmental uses. The regulations allow for a wide range of possibilities. In Malaga province, reclaimed water is used for the aforementioned golf courses, to cool the Campanillas combined-cycle power plant, to irrigate gardens such as those in Peñón del Cuervo, an idea that will now be extended to Churriana and Torremolinos, and for the Axarquia countryside. There are also projects to recharge aquifers.
Refining the effluent
“The regulations set very demanding standards for chemical and water quality parameters. These requirements also vary significantly depending on the intended use of the water. For instance, reclaimed water used to irrigate crops has different requirements depending on whether it will come into direct contact with the fruit or not.
The Costa del Sol consumes between 90 and 100 million cubic metres of water per year. Around 60% of this comes from La Concepción reservoir. Starting this summer, another 20 million cubic metres can be obtained from the modernised and expanded Marbella desalination plant. Another 11 come from wells (Fuengirola and Guadalmansa). Barely seven million cubic metres come from reclaimed wastewater, as mentioned before. Acosol aims to increase this figure to 30 in the medium term. That would automatically reduce the pressure on drinking water resources by a third.
The water companies are working hard to overcome prejudices about reclaimed water, emphasising how, in other parts of the world, it truly is drinkable water, given the exhaustive treatment and technological advances to make it safe. In addition, the distribution networks must logically be expanded.
