The importance of monitoring wastewater discharged by treatment plants

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This study, led by doctors Yolanda Valcárcel and Yolanda Segura with the collaboration of Francisco M. Martín, is included in the line of work on surveillance of chemical substances linked to human presence that has been developing for some years in coastal waters and Beaches. The objectives of this research are to evaluate the environmental risk of these substances and propose actions for their adequate management. “This report is based on data from the Administration itself, since they belong to the Segura Hydrographic Confederation (CHS), and details that 66 percent of the controls carried out (43 out of 65) in the Torre Pacheco treatment plant during the study period (2019-2022) did not comply with any of the legal limits,” the researchers highlight. This is the main conclusion of the results of the study that analyzes different parameters in effluents in the Mar Menor and that has been presented during the XVII Spanish Congress and the VII Ibero-American Congress of Environmental Health.

The scientific team states in this report that the Torre Pacheco treatment plant (Murcia) repeatedly failed to comply with the permitted limits in parameters such as conductivity, suspended solids, chemical oxygen demand, biological oxygen demand or nutrients such as nitrogen, which are related to the environmental degradation of aquatic systems. This shows that “the problem of wastewater discharges into the lagoon does not occur in specific episodes, but on a continuous basis. These effluents provide, among other substances, organic matter and nutrients such as nitrogen and phosphorus, intervening directly on eutrophication - excess of inorganic nutrients from human activities - and on events of decreased oxygen concentration in the lagoon," as detailed in the report.

These non-compliance would indicate, therefore, a poor purification capacity of the plant, continuously contributing to the pollution of the Mar Menor and the non-regeneration of its waters. In this sense, the scientific team advises analyzing the effluents of all the treatment plants that discharge into the lagoon in accordance with the recommendations established by the European Directive, since these data are old, and it is necessary to have current data, to evaluate the improvements that have been undertaken during this time.

The report recommends prioritizing the new draft of the Directive on wastewater treatment and monitoring compliance with the parameters already legislated, as well as those not legislated in order to contribute together to protect the environment and human health.