The STORMFILTER cartridge
The Stormfilter® is one of the most advanced, innovative, efficient and well-known BAT (Best Available Technology), among stormwater treatment systems.
The Stormfilter® system typically consists of filtering cartridges, the number depending on the stormwater inflow, that are used to remove particulate matter and pollutants, such as dissolved metals, nutrients and hydrocarbons. A siphon effect allows the activation of the system and the discharge of treated water.
Stormfilter® is a conceptually straightforward, easy to install and maintain technology.
Each filter has a high hydraulic capacity constantly set to 1 l/s, (3.6 cubic meters per hour) for the ‘small’ model, or to 2 l/s (7,2 cubic meters/hour) for the ‘big’ model. The removal efficiency of each filtrating cartridge, for different pollutants, is displayed on the side, although the function of inlet flow is strictly related to the quality and quantity of the water. Particular care must be engaged to the dissolved pollutants, especially to metals and to the finest fraction of particulate matter. The hydraulic side of stormwater management cannot be neglected as well: following the ‘first flush’ we are faced with almost the whole flow to be managed. Pollutants can be mobilized by intense precipitations; however, that does not correspond to the first flush and occurs later. For this reason, StormwaterItalia designs systems to treat and manage about 96% of the annual precipitations.
Stormfilter® cartridges have the following configurations:
1.0 liters per second
1.5 liters per second
2.0 liters per second
Furthermore, the filters can be modified to operate with a low hydraulic head, whenever the difference between inlet and outlet flow is very low.
Treatment plants can be installed inside precasted vaults to combine simplicity with the typical high quality of tailor-made solutions. Pre-casted vaults are designed to withstand a load up to 90 tons (load class F900 for port/airport installations) and are provided with manholes for inspections and maintenance
For above-ground installations digging is not necessary and construction works are very limited.
Treatment solutions can be located inside a manhole or associated with curb inlets or catchment basins, to treat continuously the water as soon as it enters the drainage network. In these situations, the plant configuration contemplates two parts: a sedimentation tank, where heavier particles settle, and a filtration unit, where the Stormfilter® cartridge is located.
Fine particles and dissolved pollutants are removed through the filtrating action performed by the media filtrating. Treated water is conveyed to the discharge drain pipe. The Stormfilter manhole configuration can treat a water flow from 1 to 4 liters per second, corresponding to a 1000 square meters area. If the flow rate is higher than the one managed by the treatment system, the exceeding flow is conveyed the outlet through an overflow pipe, in doing so it avoids the re-suspension of particles settled on the bottom of the basin.