Can plastic waste efficiently be removed from waterways before it reaches the ocean, or even if it has already entered the ocean? Which technologies are suitable and where are they most effective? This report examines different approaches to removing plastic waste from wastewater, rivers, harbours, coastal areas and the open sea. It draws on scientific studies, recent reports, information provided by technology developers, and expert interviews.

A large share of plastic waste in the environment enters the seas and oceans via rivers, making them a central sink for inland waste. At the same time, part of this plastic is washed back onto coastlines and beaches. In the environment – particularly in sensitive aquatic ecosystems – plastic waste causes harm to flora, fauna and ecosystem functioning. Various companies, associations and organisations are working to remove waste from seas and oceans or to intercept it in wastewater and rivers before it reaches the marine environment. To this end, a range of technologies has been developed.

The analysis shows that many of these technologies are already in use. The report assesses their efficiency, ecological risks, suitable conditions for deployment, and the handling of recovered waste. Based on this, it outlines possible application scenarios and relates their effectiveness to waste prevention strategies.

Key findings of the report include:

• A combination of preventive measures and the targeted application of plastic removal technologies offers the greatest potential to sustainably reduce pollution in aquatic environments.
• Efforts should focus in particular on wastewater, rivers, estuaries and harbours, where plastic can be collected more efficiently and greater ecological damage can be avoided.
• Due to limited efficiency and potential environmental impacts, the removal of plastic waste from the open ocean should be restricted to exceptional cases, such as the recovery of ghost nets or responses to maritime accidents.
• To date, there has been a significant lack of scientifically sound information on the effectiveness of these technologies. There is a need for harmonised monitoring standards to assess unintended environmental impacts, efficiency, and appropriate areas of application.

At the same time, it is important to note that while technological solutions can remove existing waste, they do not address the root causes of marine pollution. Without systemic change, plastic will continue to enter the oceans—and volumes are likely to increase.

The report was commissioned by the Office of Technology Assessment at the German Bundestag (TAB). It has been incorporated into the TA-Kompaktstudie Nr. 5 (doi:10.5445/IR/1000191167).