Discharge limits for water: What to consider

Establishing requirements and procuring water treatment solutions for large-scale projects can be complex. While it may be tempting to take shortcuts and look at what others have done before, there are certain questions that need to be answered in order to successfully establish discharge requirements. Below, we have compiled a list based on shared recommendations and experiences from different stakeholders across the industry regarding the factors that should be considered when establishing water discharge limits.

1. Contract type and projects phases

What type of construction project will be carried out, and which activities will take place over time? Different phases of a project generate water with varying characteristics and contaminant profiles. To select the right water treatment solution, it is therefore important to understand the types of water that will be generated throughout the project.

2. Site history and ground conditions

What is the history of the site and what are its characteristics? What types of activities have previously taken place there—industrial operations, dry-cleaning facilities, landfills, shipyard activities, or something else?

3. Characteristics of the recieving water body

Which receiving water body will be used after the water treatment process? Depending on the receiving water body, discharge limits can—and should—vary. There is a significant difference between discharging water into a stormwater system, a wetland, or a major river.

4. Water sampling

It is important to conduct water sampling well in advance and over an extended period of time. Ideally, sampling should begin at least one year beforehand so that contaminants can be identified and any seasonal variations can be assessed, for example due to leaching or other natural phenomena.

5. Avoid copying discharge limits

Avoid copying discharge requirements from one project to another. Every site is unique and has its own conditions. In some cases, requirements for a very high treatment efficiency are imposed even though the receiving water body is not particularly sensitive. In other cases, the requirements are too lenient despite a sensitive receiving environment.

6. Maintain a broad perspective

Try to maintain a broad perspective. It is important to understand the practical consequences that proposed discharge requirements may have for all involved parties. Strive for discharge limits that are as strict as possible while ensuring that they remain reasonable based on site-specific conditions. Discharge limits are often difficult to revise afterward and involve complex processes.

7. Cross-sector cooperation

Encourage cooperation across organizational boundaries whenever possible. Authorities, municipalities, contractors, and water treatment companies all bring different knowledge and perspectives. It is when we discuss challenges and their solutions together that we find the right path forward.

The industry’s goal—and ours—is to promote dialogue across organizational boundaries. That is why we launched SweWater Summit, an annual Swedish industry event, which aims to increase knowledge about water management, regulations, and compliance while also providing a valuable opportunity to exchange experiences and share knowledge with one another.

Important to keep in mind

The order of the topics in this list will vary from project to project. In some cases, the receiving water body should be the starting point, together with the supervisory authority and/or the County Administrative Board. In other cases, discussions with the municipality may need to come first in order to understand the site’s history. Sometimes, the project’s different activities and phases must be mapped out before the remaining questions can be answered.