Hydrodynamic pretreatment of rainwater
DDSelect™ vortex separator
The DDSelect™ hydrodynamic clarifier is a compact and efficient solution for the pretreatment of rainwater and surface runoff. The system removes suspended solids (TSS), heavy metals, PAHs, and light liquids prior to infiltration or discharge, thereby protecting downstream systems and the environment.
Why pretreatment of rainwater is essential
Rainwater originating from roads, industrial zones, and parking lots often contains suspended solids (TSS), hydrocarbons and oil fractions, heavy metals, and nutrients. Without pre-treatment, these cause, among other things, clogging of infiltration systems, reduced permeability, increased maintenance costs, and the risk of soil and water contamination.
Pretreatment is therefore crucial within sustainable water management strategies and regulations such as the EU Urban Wastewater Directive (91/271/EEC).
Operation of the DDSelect™ vortex separator
The DDSelect™ operates on the principle of hydrodynamic decantation with a vortex effect:
- Controlled rotation (swirling) of the water flow
- Combination of gravity and centrifugal force
- Separation based on density and particle size
The result is the sedimentation of heavy particles in the lower zone with the trapping of floating matter and light liquids at the surface. This ensures safe storage in the separator without resuspension of pollutants.
What contaminants are removed?
The DDSelect™ removes macro- and micro-waste, suspended solids (TSS), heavy metals (bound to sediment), PAHs and hydrocarbons, light liquids and oil fractions, and microplastics, among other things.
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Integration in rainwater management (SuDS / infiltration concepts)
The DDSelect™ is an integral part of a sustainable rainwater management concept at, among others:
- Pre-treatment for infiltration crates
- Protection of buffer basins
- Integration into separate sewer systems
- Application in Sustainable Drainage Systems (SuDS)
The system ensures that only uncontaminated water infiltrates, which is essential for long-term performance and environmental protection.
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Applications of DDSelect™
The DDSelect™ is an integral part of a sustainable rainwater management concept at, among others:
- Pre-treatment for infiltration crates
- Protection of buffer basins
- Integration into separate sewer systems
- Application in Sustainable Drainage Systems (SuDS)
The system ensures that only uncontaminated water infiltrates, which is essential for long-term performance and environmental protection.
Installation of DDSelect™ in industry and infrastructure
The DDSelect™ is suitable for:
- Industrial sites and Seveso environments
- Logistics zones and parking lots
- Road and infrastructure projects
- Pretreatment prior to infiltration (crates, buffers, swales)
- Protection of rainwater systems
The system is typically placed upstream of infiltration or buffer solutions to sustainably protect those systems.
Key benefits for engineers and engineering firms
- Compact design – minimal installation space
- High removal rate of pollutants
- Protection of infiltration systems and geotextiles
- Lower downstream maintenance costs
- Easy maintenance via top access
- In accordance with European regulations
FAQ
1. Where is a DDSelect™ typically placed in a water management system?
By pre-treating the runoff water, the system prevents suspended solids and pollutants from reaching these facilities, thereby clogging and loss of infiltration capacity are avoided.
2. How does the DDSelect™ contribute to the lifespan of infiltration systems?
By efficiently removing suspended solids (SS/TSS) and sediment-bound contaminants, the DDSelect™ prevents the clogging of geotextiles and infiltration media.
This results in:
- A preservation of permeability
- Less maintenance
- A longer lifespan of the entire system
3. In which industrial applications is a hydrodynamic separator recommended
A system like the DDSelect™ is particularly suited for:
- Industrial sites and logistics hubs
- Parking lots and loading zones
- Road infrastructure
- Sites with an increased risk of pollutants (e.g., hydrocarbons, metals)
These applications generate runoff with a high contaminant load, which must be removed via pre-treatment prior to discharge or infiltration.
4. How does the DDSelect™ integrate into sustainable drainage systems (SuDS)?
The DDSelect™ is an important link within Sustainable Drainage Systems (SuDS) and other infiltration concepts.
The system:
- Acts as a pre-treatment step for natural or technical infiltration facilities
- Helps meet water quality objectives and regulations
- Ensures that only sufficiently purified water infiltrates the soil.