Metals – particle‑bound and dissolved

Metals appear in many types of water originating from construction and infrastructure projects. Common examples include copper, zinc, nickel, and lead, but iron and aluminum may also be present depending on materials and site conditions.​ Concentrations can vary significantly and depend on both the composition of the soil and the materials used in the project or operation.

Where do the metals come from?

• Soil and bedrock: Natural metal content can be released during excavation, drilling, or blasting.
• Construction materials: Roofs, pipes, coatings, and surface treatments can leach metals, especially when exposed to rain or process water.
• Contamination: Previous activities at a site may have left behind polluted soil containing residual metals.
• Industrial activities: At facilities such as recycling centers, metals can be introduced through waste materials, stored goods, or the handling of scrap metal, as well as through water that comes into contact with contaminated surfaces and materials.

Challenges in water treatment

Metals occur both as dissolved ions and bound to particles. This means they must be treated using different methods:

• Dissolved metals require chemical treatment or filter media designed to bind metal ions.
• Particle‑bound metals can be removed through flocculation and sedimentation.

In addition, many metals become more soluble at high or low pH levels, which means pH adjustment may be necessary for the treatment process to work effectively.

The solution

Metals are very common contaminants, and their form — dissolved or particle‑bound — determines which treatment technology is most effective. Swedish Hydro Solutions uses several methods to achieve the intended water quality. We adjust the pH at least once during the treatment process. Our HydroBox, which doses chitosan, ensures optimal flocculation and removes the particle‑bound metals. The dissolved metals are then filtered out using BioMedia filters or a pressurized carbon or sand filter, depending on the incoming water quality. This treatment approach is highly effective and consistently removes metals to levels well below the limits for treated water.

Read more about the technology