In her introductory presentation, Dr Adrienne Clement, Associate Professor at Budapest University of Technology and Economics (BME), highlighted that stormwater runoff quality from roads varies significantly by location and over time. Annual average pollutant concentrations can even be of the same order of magnitude as those in treated wastewater. In addition to conventional pollutants, such as toxic heavy metals, total petroleum hydrocarbons (TPH) and polycyclic aromatic hydrocarbons (PAHs), increasing attention must be paid to emerging micropollutants, including per- and polyfluoroalkyl substances (PFAS), commonly known as “forever chemicals” because of their extreme persistence in the environment.
The lively panel discussion that followed provided a forum for representatives of academia, research, design, construction, operation, regulatory authorities and the engineering profession to jointly explore current challenges, anticipated changes in the regulatory framework and potential solutions for the future.
The moderated discussion focused on how stormwater management is perceived within the sector, Hungary’s regulatory and permitting practices, available technical solutions and the future challenges arising from changes in transport technologies.
The roundtable participants agreed that pollution in stormwater runoff from roads is a genuine environmental concern that requires solutions meeting contemporary technical and environmental standards. The question is not whether treatment is necessary, but which technologies can deliver it effectively.
By aligning regulatory, design and operational perspectives, systems must be developed that are not only environmentally effective but also economically viable and sustainable to operate over the long term.
Environmental protection is expensive, but the cost of inaction and poor decisions may be even higher.
The discussion brought together the President of the Water Engineering and Water Management Division of the Hungarian Chamber of Engineers, a senior engineer from the Operations and Maintenance Department of Magyar Közút (Hungarian Public Roads), a water management officer from the Fire Protection, Industrial Safety and Water Management Authority Department of the Pest County Government Office, and a representative of the civil engineering design profession. The discussion was moderated by the Head of the Stormwater Working Group of the Hungarian Water and Wastewater Technology Association (MaSzeSz).
Key topics discussed by the panel
The role of stormwater management in professional practice
The contributions highlighted that stormwater management is still frequently regarded as a technical and permitting obligation associated with an infrastructure project, rather than as part of a comprehensive approach to water management.
Participants emphasised the importance of raising awareness and strengthening cooperation across professional disciplines. Stormwater management is inherently multidisciplinary, requiring an integrated approach that considers water engineering, transport infrastructure, environmental protection, design and operational requirements.
What are the greatest pollution risks in road runoff today?
Alongside traditionally recognised pollutants such as oil, suspended solids and heavy metals, increasing attention is being paid to particles generated by tyre wear and to microplastics. The discussion highlighted that the water quality challenges associated with road runoff are far more complex than can be assessed by considering oil pollution alone.
The significance of stormwater-related pollution is also recognised in the European Union’s revised Urban Wastewater Treatment Directive (EU 2024/3019). The Directive establishes an indicative target of 2% for reducing untreated wastewater discharges from combined sewer systems during heavy rainfall. Under this non-binding target, the annual pollutant load discharged through such overflows should not exceed 2% of the annual urban wastewater load collected under dry-weather conditions.
Because stormwater pollution levels vary considerably over time, conventional concentration-based discharge limits are difficult to apply. Greater emphasis is therefore being placed on appropriate treatment technologies and nature-based solutions that support stormwater retention, infiltration and reuse.
However, the effective and cost-efficient implementation of these approaches requires pollutant load estimation methods adapted to Hungarian conditions, clear design guidelines and practical guidance based on proven solutions.
Are Hungary’s regulations and treatment requirements sufficiently clear?
The perspectives of regulatory authorities, designers and operators highlighted that applying existing requirements in practice often presents significant challenges.
Clarifying responsibilities is closely linked to these regulatory issues. Road runoff management requires cooperation between several stakeholders, and it is not always clear who is responsible for individual tasks or for the long-term operation, maintenance and monitoring of treatment facilities.
Participants also discussed enforcement and penalties, emphasising that regulatory requirements must not only be clearly defined in law but also be practically enforceable.
Oil separators or integrated stormwater treatment solutions?
The design of stormwater treatment systems must be adapted to site-specific pollution risks, runoff volumes and the characteristics of the receiving environment.
In addition to conventional treatment structures, sedimentation, filtration, vegetated swales, infiltration systems and combinations of these technologies can all play a role.
However, the changing range of pollutants – including microplastics, heavy metals and persistent chemicals such as PFAS – calls for more integrated treatment systems and solutions capable of achieving higher removal efficiencies.
How will electric mobility change road runoff treatment?
The transition to electric vehicles does not, in itself, eliminate water quality problems associated with road transport.
Tyre wear remains a source of pollution, and its significance may evolve as transport technologies change. The relationship between vehicle weight and the quantity of particles generated through tyre abrasion is therefore an important topic for future research.
Future developments may consequently require a reassessment of stormwater treatment design criteria and water quality monitoring methods, particularly in relation to emerging pollutants.
Conclusions
The key message of the roundtable was that modern stormwater treatment is about developing integrated solutions that reflect local conditions, pollution risks and operational requirements, while remaining sustainable, easy to maintain and effective over the long term.
The professional dialogue initiated by MaSzeSz provides an opportunity to bring together regulatory, design, scientific and operational experience, helping to advance stormwater management practices in Hungary.
