Stormwater runoff systems

The plant allows the continuous treatment of stormwater runoff from impermeable surfaces up to 27000 m2 used for transit or parking in industrial areas, residential zones and service stations subject to possible pollution from mineral oils, hydrocarbons, sand/grit and inert materials

Use and specifications
1. FLOW SPLITTING CHAMBER: carries the collected rainwater from the hardstanding to the storage tank and, when this is full, carries the secondary rainwater directly to the end drain through the bypass pipe.

2. GRIT SEPARATOR SECTION: stilling tank in which the heavy substances (stones, grit, pieces of rubber and metal,…) settle and accumulate on the bottom of the tank. At the same time the larger light components (drops of oil, hydrocarbons and any foam) accumulate on the surface.

3. COALESCING FILTER TYPE OIL SEPARATION SECTION: thanks to the fine micro-bubble polyurethane coalescing filter inserted into a stainless steel grid, which can be extracted thanks to the presence of a base and guides, also made of stainless steel, the fine particles of oil and hydrocarbons join together to form drops that are large enough to migrate towards the surface, separating from the effluent.
TECHNICAL CHARACTERISTICS

The plant allows the continuous treatment of stormwater runoff from impermeable surfaces up to 27000 m2 used for transit or parking in industrial areas, residential zones and service stations subject to possible pollution from mineral oils, hydrocarbons, sand/grit and inert materials. The stormwater runoff treatment system makes use of the action of a grit and oil separator in continuous operation capable of treating flows of up to 150 l/s. Runoff from impermeable transit areas must be carried to the treatment system. The treatment tanks receive the flow appertaining to first 5 mm of rain falling over a 15-minute period. For higher flows, the by-pass is activated which sends the excess to the stormwater storage tanks. The treatment plant consists of a grit separator and an oil separator with coalescing filter, thus ensuring that the final effluent possesses the appropriate characteristics for discharge to a body of surface water (Appendix 5 table 3 Law Decree 152/2006). The plant is effective for the following parameters: 

  • Sedimentable solids. 
  • Total hydrocarbons and other light liquids that have not been emulsified of specific weight up to 0.85 g/cm3. 
  • Unless otherwise specified, the peak flows in m³/h for each single model must be less than that indicated on the technical data sheet. 
  • Unless otherwise specified, the surface area (m2) of the hardstanding to treat for each single model must be less than or equal to the limits indicated on the technical data sheet. 
  • For that not specifically indicated, refer to the design data specified on the technical data sheet. 

USE: treatment of surface drainage water from open-air hardstandings, car parks, roads, service stations, warehouses,… 

REFERENCE REGULATIONS: Law Decree 152/2006, standard UNI EN 858-1 (oil separator), regional standards for treatment of rainwater.

INSTALLATION EXAMPLE
MODELS
One-piece

from 11000 m2 – 65 l/s to 27000 m2 – 150 l/s
With separate tanks

(up to 9000 m2 – 50 l/s)

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