In projects and when setting requirements for emission limits, it is crucial to have a clear understanding of the type of water being handled. This is important from several perspectives:

• To identify specific pollutants and risks

• To select the appropriate treatment methods

• To comply with applicable laws and regulations

• To assess the environmental impact

• To achieve efficient and cost-effective solutions

For example, stormwater may contain oil and heavy metals, while dewatering water from construction sites often has high levels of suspended materials and metals. Therefore, different treatment and treatment methods are required depending on the water’s characteristics.

By identifying the type of water being handled, the most efficient and cost-effective treatment technique can be selected, which improves the treatment process and saves resources. This also ensures compliance with relevant laws and regulations, minimizing legal risks and potential fines. Finally, it contributes to protecting our environment.

So, what types of water do we handle in our projects? Here are the five main water characteristics we refer to:

1. Dewatering Water

Dewatering water, or groundwater control water, is a common term in certain sectors, especially in construction and civil engineering. There is no legal definition of dewatering water, but it generally refers to water that is diverted from some form of human activity. In practice, this includes rainwater, infiltrating groundwater, and process water generated during excavation, blasting, and drilling, such as in earthworks, quarries, and mines.

Typical contaminants in dewatering water include high levels of suspended solids and metals. Additionally, during casting operations, elevated pH levels may need to be adjusted, and treatment for hexavalent chromium may be required.

2. Stormwater

Stormwater is rain or meltwater that runs off roofs, roads, and other impervious surfaces. If it rains heavily or the snow melts quickly, stormwater can collect pollutants from these surfaces, such as oil, heavy metals, chemicals, and debris, before it continues to flow and eventually reaches water bodies, lakes, or even groundwater.

3. Industrial Stormwater

Industrial stormwater primarily refers to rainwater that has come into contact with industrial activities and surfaces. Recycling facilities, for example, are one industry where dissolved metals are found in industrial stormwater, which must be treated before being discharged.

4. Process Water

Process water is water used in industrial processes such as manufacturing, cooling, or cleaning. After use, process water may be contaminated with chemicals, oils, heavy metals, or other pollutants generated during the industrial process.

5. Leachate

Leachate is water that has come into contact with waste deposited in a landfill and is either drained away or retained within the site. It is primarily generated when rainwater infiltrates the landfill or when water is squeezed out of the waste due to compaction. In older landfills, leachate can also form when groundwater or surface water seeps into the waste facility. The amount of leachate produced at a landfill depends on factors such as rainfall, waste decomposition, and ambient temperature.

The pollutants in leachate vary depending on the type of waste in the landfill, but it typically contains a mix of suspended solids, organic matter, heavy metals such as zinc, chromium, and cadmium, as well as BOD (Biological Oxygen Demand) and/or COD (Chemical Oxygen Demand). It may also contain high levels of nutrients like nitrogen and sulfur.