Why are biomedia an environmental plague?


Used in wastewater treatment plants to clean up sewage, biomedia are one of the most effective technologies in the wastewater treatment market. However, filter media are a threat to the ocean and  source of a large-scale plastic pollution. As we find thousands of them on Europe's beaches and shores, we can wonder about the impact of these biocarriers spills, which constitute an additional source of risk for the health of the environment but also for human health.

Biofilter media pollute

Plastic filters are an additional source of plastic pollution that can affect marine biodiversity. Like other plastic waste, biomedia can be mistaken for food by marine fauna : numerous cases of filter media ingestions by birds and sea turtles have been reported.  

Inside the stomach of a Mediterranean sea turtle © G. Darmon & D. Gambaiani

Designed to fix bacteria, biomedia could be used as a support for other substances present in wastewater. Wastewater arriving in treatment plants is loaded with pollutants (fecal bacteria, viruses, industrial products, detergents, hydrocarbons, pesticides, cosmetics, drugs). In the event of an accident and discharge, biocarriers will disperse and transport the pollutants that they have concentrated or that they may absorb once in the aquatic environment. This raises the question of the impact of biomedia leakages, constituting an additional source of risk for the health of the natural environment as well as for human health. Initially used as a depollution tool, biomedia turn out to be very polluting.

Two examples to understand biomedia pollution

Since the widespread use of this technology and the first biomedia pollution in the 2000s, Surfrider has investigated more than 40 cases of major accidents, allowing to identify the sources of this pollution.

In terms of scale, one of the major pollution cases in recent years occurred in 2018 in southern Italy in the province of Salerno, following a malfunction at the municipal wastewater treatment plant of the town of Capaccio Paestum. An estimated  130 million biomedia were discharged into the Sele River, inevitably ending up into the Mediterranean Sea before reaching the coasts of France, Spain, Tunisia and Malta. In early 2021, a trial opened in Italy to determine who was responsible for this environmental disaster. The trial involves all the operators in the wastewater treatment sector  (installators, municipality and community, manager of the treatment plant). This is the first time that pollution by biomedia has been taken into account by the courts in Europe.

In Corsica (France), an incident occurred in 2020 in Bastia agglomeration's wastewater treatment plant. The public authority responsible for operating the plant has acknowledged a design flaw that led to the loss of one and a half million biomedia and has so far ensured that the necessary work has been done to prevent any further incidents.  Nevertheless, tens of thousands of biomedia were found and are still being collected on the island's beaches following the incident. They are also found in the stomachs of sea turtles living in the Mediterranean, testifying of the extent of this pollution.

What are the solutions?

Surfrider Foundation Europe calls on users of biomedia to ensure the establishment of a closed circuit and the installation of retention systems in their stations to prevent any leakage of biomedia into the environment. We ask them to notify the competent authorities as soon as possible in the event of an accident in order to avoid any dispersion of biomedia and to prevent potential consequences on the natural environment.

We also call for the adoption of regulatory measures at the national and European levels to regulate all stages of the biomedia value chain and to allow for controls on the use of this technology in collective and industrial wastewater treatment plants by the competent authorities.

As citizens, you can join us: whether you are on vacation, out walking or practicing water activities, if you find biomedia report it to help us monitor and limit the impact of this plastic pollution.

It is a testimony of a volunteer worried to see these plastic discs proliferating on the beaches that allowed Surfrider Foundation Europe to raise the alarm about this new plastic pollution.

Every testimony counts and we need your help to make things happen.

So if you find biomedia please fill in this form or contact us for more information.

Thank you for your support.

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