ARCHIVED - After 3½ years lemon wood shavings replace green filters in Murcia government plans to protect the Mar Menor

The projected green filter in the Rambla del Albujón would have treated the amount of water currently flowing into the lagoon

Almost three and a half years after the regional government of Murcia announced that one of the key elements in a raft of measures to protect and regenerate the marine environment of the Mar Menor would be a series of “green filters”, statements made by Miriam Pérez, the head of the Department of the Mar Menor in the current regional government, seem to imply that an alternative course of action consisting of “bio-reactors” in water treatment pools is preferred.

In June 2016, during the episode of eutrophication which turned the water in the Mar Menor greenish in colour, it was decided that “green filters” similar to those which have already proved a success in the wetlands of the Albufera just south of the city of Valencia should be created in order to remove harmful nitrates and phosphates from runoff water before it reaches the lagoon. Permission was granted by the then Ministry of the Environment immediately, the idea being that the underwater outlet pipes which already exist in San Pedro del Pinatar and Cabo de Palos would also be called into service and that the costs involved would be shared by the regional and national governments.

But three and a half years later, with another drastic deterioration of water quality in the Mar Menor having occurred since the gota fría storm of September, the green filter project has made little if any progress. In 2017 it was announced that a 19-hectare filter in the Rambla del Albujón would make it possible to treat 200 litres of water per second – coincidentally, almost exactly the flow rate reported on Tuesday by Fernando López Miras, the president of the Murcia government – and academic research appeared to suggest that this approach would be effective, but since than the project has been slowed down, downsized and, to a certain extent, forgotten.

In the light of the latest crisis in the Mar Menor Miriam Pérez explains that the preferred plan now is to shelve the green filters and instead install a series of 16 pools in which water will be de-nitrified before reaching the lagoon, each of them fitted with bio-reactors in the form of shavings from lemon and other citrus fruit trees. The pools, she adds will be located along the Rambla del Albujón, the Rambla de la Maraña and the D-7 drainage channel, and will be created “instead of the green filters”.

It is to be hoped that progress towards the creation of these pools will be more rapid than was the case with the green filters, but in the meantime Sra Pérez echoed the call made by Sr López Miras for the CHS water authority to begin pumping water out of the Rambla del Albujón.

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