Project Description

FP-McCann-Precast-Drainage-Storm-Cleanser-1 STORMCLEANSER™


Johnny McCollum – Northern Ireland

028 7954 9045

Trevor Beddow – Great Britain

01530 240000

Michael Hassan – Republic Of Ireland

07809 553040

FP McCann has designed and developed the enhanced StormCleanser™ for the treatment of urban catchment stormwater run-off.

The StormCleanser™ provides a cost-effective solution for designers, engineers and contractors involved in the provision of Sustainable Drainage Systems (SuDS). This unit has no moving parts, requires no power, and is constructed within standard precast concrete chambers.

The standard units come factory fitted in precast chambers and could also be installed on-site as required. The modular stainless steel built assembly is designed to provide installation simplicity. The separator internal assembly is fabricated out of stainless steel (304L/316L), per BSI BS EN 10088-2-2014. Stainless Steel material grade and composition, provides exceptional longevity due to high corrosion resistance. The lifespan of the internal assembly outlasts the lifespan of a typical precast concrete structure (100+ years).

The enhanced StormCleanser™ design allows for an inlet at varying angles with respect to the outlet. Moreover, the design also enables configuration with multiple inlets, at different orientations and of various sizes. The symmetric inlet design provides the freedom of clockwise or counter-wise flow direction, and allows the vortex formation with minimal hydrodynamic losses and turbulence.

Fixed flow direction separators tend to lose efficiency especially when a higher flow inlet is placed ahead of a lower flow inlet. The changeable flow direction provides drainage engineers the freedom to set the desired orientation of multiple inlets. StormCleanser™ allows for preferential flow direction of the main inlet, providing optimum performance for a wide range of configurations. StormCleanser™ is developed with state-of-the-art hydraulics technology, using Computational Fluid Dynamics (CFD) modelling and full-scale experimentation.



The StormCleanser™ is specifically designed to remove suspended solids, hydrocarbons, and floatable debris from the stormwater runoff. Water and pollutants enter the system via the inlet pipe, where the internal geometry enables low energy forced vortex flow patterns. This allows the floatables to gather and solids to settle to the bottom of the treatment chamber for subsequent removal.

Settled sediment is retained within the sump storage of the unit, allowing easy access for suction cleaning. Re-suspension of the solids is minimised by the provision of a baffle plate (Catch Skirt), positioned above the sediment storage sump. A central core allows for convenient suction hose entry down to the sump for cleaning and maintenance. If there is a stormwater surge in excess of maximum treatment flow rate, it overflows a weir, bypasses the treatment zone and directly discharges through the outlet pipe. This helps to minimize the effects of scour within the treatment region and prevents wash out of retained sediment downstream.


  • Developed at inhouse high-flow Hydraulic Rig, and rigorously tested against actual rainfall inlet conditions
  • High retention at most frequent rainfall events per annum
  • High treatment flow rate to size ratio preventing oversized separators in the drainage design i.e. minimise footprint
  • Wide range of chamber sizes (Ø1200 – Ø4000mm) and pipe sizes (Ø150 – Ø900mm)
  • Tested using extremely fine sand particles starting from 2μm
  • Modular and innovative design for multiple inlet orientation
  • Choice of flow direction providing optimal configuration performance
  • Complies with SuDS legislation


  • SuDS based drainage networks
  • Housing Developments
  • Retail Parks
  • Commercial Centres
  • Leisure Facilities
  • Industrial Developments
  • Highway Drainage Products
  • Car Parks, Roads, Motorways and Trafficked Areas
  • Existing surface water sewer discharges

SuDS Pollution Mitigation Index (PMI)