How the Danish EPA is streamlining environmental assessments to better protect marine waters

Cloud-based spill modelling tool helps the agency quickly screen predicted discharges, such as from water outlets, to support impact assessment 

The Danish Environmental Protection Agency (Danish EPA) plays a crucial role in protecting Denmark's environment, guided by the evolving standards of European environmental regulations. As our understanding of the impacts on ecosystems and human health deepens, these regulations become increasingly specific and stringent, leading to more intensive monitoring and reporting across a growing number of environmental parameters. This creates greater demands for accurate, comprehensive assessments before permits are granted for proposed solutions or designs – including discharge outlets for wastewater from municipality or industrial treatment plants.

To support this, the Danish EPA uses DHI PlumeCast, a cloud-based solution for modelling spills and discharges and their dispersion in water bodies. The tool helps the agency improve decision-making when screening predicted discharges and supports regulatory compliance, particularly in safeguarding marine ecosystems. Its intuitive web interface enhances accessibility for non-experts without compromising the quality of impact assessments.

Challenge

The Danish EPA needs a more efficient way to review applications for solutions and designs that may affect the quality of receiving waters. At the same time, strict EU regulations, including the Water Framework Directive, Marine Strategy Framework Directive and Wastewater Treatment Directive, introduce risks in the various solutions where discharges might not meet environmental standards due to exceedance of thresholds. 

Key challenges included:

• Accurately assessing applications to determine whether proposed solutions and designs should be permitted, considering information provided by the applicant, such as discharge quantities and concentrations
• Quickly screening predicted discharges and determining dilution conditions in receiving waters 
• Ensuring that the assessment process incorporates best available technology standards to protect water quality and ecosystem health 

Solution

A screening tool was proposed and developed for the Danish EPA to support the assessment of environmental and water quality impacts.
 
The Danish EPA and DHI collaborated to identify a solution, i.e., DHI PlumeCast, to address the agency's challenge of determining dilution conditions in receiving waters. In other words, the tool helps figure out how much a discharge is diluted once it enters a water body, and how that affects pollutant concentrations. 

DHI PlumeCast allows for high-quality modelling and assessments through a simple, user-friendly screening interface. This supports non-modellers at the Danish EPA to assess the viability of submitted applications against EU regulations and determine whether they are potential ‘go/no-go’ solutions. This method is considered the best available technology (BAT) for screening tools in Denmark, offering a streamlined, cost-effective alternative to more complex modelling solutions. Without DHI PlumeCast, the client would have relied on rough estimations or costly, time-consuming custom models, which would have delayed decision-making when assessing whether an application can be permitted.
 

Results

The marine environment is under increasing pressure from various sources, leading to habitat degradation and pollution. With new substances constantly emerging, timely and precise assessments of point sources are crucial. Solutions like DHI PlumeCast help the Danish EPA better understand and manage how flows and discharges impact marine environments, supporting ecosystem protection and the agency’s role in safeguarding environmental health. DHI PlumeCast also enables science-based screenings, replacing previously used generalised dilutions. This enhanced capability offers much greater confidence in the accuracy and reliability of the screenings compared to past methods.