Technical Solutions · Rainwater Treatment
Treat runoff before it reaches waterways
Substrate filtration, sedimentation and hydrodynamic pre-treatment sized for Australian projects — aligned with DWA practice for groundwater and surface-water discharge.
Civil & commercial stormwater - WSUD detention and treatment
GRAF Treatment Hydroshark sedimentation plant
Manufacturer product photography with system steps listed alongside
Also in this system
System steps
Stormwater treatment train
Civil runoff is treated through GRAF Treatment Hydroshark sedimentation, then managed with GRAF EcoBloc detention, infiltration or controlled discharge.
- 1Roof, pavement and civil catchment - runoff from impervious site areas
- 2GRAF Treatment Hydroshark - sedimentation and filtration at the treatment inlet
- 3GRAF EcoBloc Inspect modular cells - underground detention, infiltration or retention
- 4Treated flow to council-approved discharge point or soakaway infiltration
Why treat rainwater
Sealed surfaces concentrate pollution
Runoff from streets and yards does not disappear underground — it continues into rivers, lakes and groundwater that often feeds drinking-water supplies. Treatment removes floatables, oils, sediments, fine solids and dissolved metals before discharge or infiltration.
45%
of urban rainfall runs off sealed surfaces
Berlin Rainwater Agency
68%
of microplastic inputs come from traffic areas
Fraunhofer UMSICHT
>70%
of urban runoff carries mixed pollutants
MDPI
~2/3
of drinking water drawn from groundwater sources
Wasseratlas 2025
Pollutants
What treatment targets
Floatables
Packaging, butts and foam ride the water surface. An outlet baffle retains them for vacuum removal during maintenance.
Mineral oil hydrocarbons
Fuel and oil drips float on the surface and are held with floatables until servicing.
Sediments
Heavier solids settle to the tank floor — including particles that carry heavy metals and PAHs from combustion.
Fine solids (AFS63)
Particles ≤ 63 µm settle slowly. Hydrodynamic separators improve retention of these fines before discharge.
Heavy metals
Copper, zinc, lead and cadmium arrive dissolved or bound to particles. Substrate filters remove dissolved metals ahead of infiltration.
Guidelines
DWA-aligned treatment paths
GRAF systems are developed against German DWA worksheets used internationally for stormwater treatment. Match the discharge path first, then the technology.
A 138-1
Infiltration to groundwater — substrate filters (EcoPure, EcoClean).
A 102-2
Discharge to surface waters — hydrodynamic separators (EcoLoop, Hydroshark, EcoCross).
M 153
Sedimentation sizing — SediProtect, Saphir, Carat, Vario 800 EcoBloc.
Catalogue paths
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When to specify
Typical Australian applications
- Runoff from roofs, roads, car parks or industrial yards before infiltration or surface-water discharge
- Council / WSUD requirements for treatment train stages (screen → sediment → filter)
- PFAS or heavy-metal concerns on specialised catchments
- First-flush capture on highly polluted traffic areas (EcoPrimo)
Size a treatment train
Share catchment area, surface type and discharge path. We will recommend filtration, sedimentation or separator stages.
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