Green filters are designed to naturally clean the polluted Mar Menor. With wood chips from citrus trees, sunlight, oxygen and microorganisms, the water should become clean again.
Cartagena – Something is happening at the Mar Menor* on the Costa Cálida*. The government of Murcia has launched the first rescue operation for the polluted inland sea*. The €2.5 million project involves the construction of 15 bioreactors on Rambla Albujón, which flows into the Mar Menor. These are so-called green filters, which consist of water basins filled with citrus wood chips, as reported by costanachrichten.com *. The wood removes pollutants such as nitrates and phosphates from the water.
| Minor Sea | |
|---|---|
| fläche | 170km² |
| Mittlere Tiefe | 4m |
| Als Welterbestätte ernannt | 4. October 1994 |
| inseln | Isla Mayor, Perdiguera Island, Deer Island, Subject Island, Rondella Island |
Highly polluted sewage from the surrounding fields of intensive agriculture flows unfiltered and apparently inexorably into the Mar Menor via the Rambla Albujón. The consequences are clear. In the summer of 2016, the lagoon on the Murcia coast, popular with tourists, turned into a green-brown soup, in October 2019 and August 2021 tons of dead fish washed up on the beaches of the Mar Menor*. The large amounts of nitrates and phosphates from fertilizers have literally suffocated the inland sea. The images of the dead sea creatures made negative headlines beyond the borders of Spain. Even one of the main buyers of the vegetables, Aldi, got involved*.
Saving the Mar Menor: Citrus wood and olive leaves are said to purify the water
Now the contaminated waste water from the Rambla Albujón is to be cleaned by the green filter before it reaches the Mar Menor. The water is cleaned in the bioreactors with the help of sunlight, oxygen from the air, microorganisms and the branches of citrus trees. A few years ago, scientists at the Polytechnic University of Cartagena demonstrated the ability of citrus wood to bind pollutants such as nitrates and phosphates.
Not only wood from citrus trees, but also the leaves of olive trees have the ability to bind pollutants, as well as a waste product that occurs in the production of olive oil. The dark, unpleasant-smelling liquid is a mixture of the water used to wash the olives and the water contained in the olives themselves. Researchers are trying to develop a technology that prevents nitrate formation in the fields. Oysters are also considered excellent filters.
Saving the Mar Menor: Bioreactors filter 200 liters of polluted water per second
The 15 bioreactors on the Rambla Albujón should be able to purify 200 liters of water per second. That would correspond to an amount of 6.3 hectometers per year. The bioreactors will be installed on a 48,500 square meter site in Los Alcázares, 2.2 kilometers from the shores of the Mar Menor. For this purpose, agricultural land is expropriated, as the state government announced. The project is to be awarded as soon as possible so that work can begin and be completed by the end of the year.
There is a reason why the state government is putting pressure on it. If the continuous input of nitrates and phosphates into the Mar Menor is not stopped, the next big fish kill threatens in summer when the temperatures rise. *costanachrichten.com is an offer from IPPEN.MEDIA.
