The SNOUT® water quality device from Best Management Products, Inc., is a vented plastic composite outlet protection hood and stormwater trash screen that allows floatable and sinkable pollution to be removed from stormwater discharges. It is the keystone of BMPs stormwater quality system.
The SNOUT hood is a gross pollutant trap that forms a very simple hydrodynamic separator in a sumped stormwater structure that can reduce floatable trash and debris, free oils, and other solids from stormwater discharges. In its most basic application, a SNOUT hood is installed over the outlet of a catch basin or other stormwater quality structure with a deep sump.
The bottom of the hood extends well below the invert of the outlet pipe creating a separation layer on the surface. The SNOUT then forms a baffle that traps floatable debris and free oils on the surface, while permitting heavier solids to sink to the bottom of the sump. The clarified intermediate layer is forced out of the structure through the open bottom of the SNOUT by displacement from incoming flow.
The resultant discharge from this stormwater trash screen and gross pollutant trap contains considerably less unsightly trash and other gross pollutants and can also offer reductions of free-oils and finer solids.
SNOUTs are available for both flat wall structures (e.g., boxes or vaults) and for round wall structures like manholes. Pipes up to 60” ID can be accommodated, and models for up to 96” ID round structures are available as stock parts. Split SNOUTs for constrained access or retrofit applications and a series of NP SNOUTs for small round structures from 18-36” ID are available.
Since its introduction in 1999, nearly 100,000 SNOUTs have been installed. They are used by the largest municipalities in the country including New York City, Philadelphia and Chicago, by many state DOTs and on U.S. federal government and military facilities around the world. SNOUTs are also widely used in Canada.
This simple and affordable stormwater trash screen and stormwater quality improvement system has a full suite of accessories to enhance its pollution reducing capabilities. The popular Bio-Skirt® skirted boom for increased hydrocarbon reductions is a quick add-on and highly effective where oils are a pollutant of concern.
Use of the Turbo-Plate® is growing quickly where quantifiable sediment and T.S.S. reductions are required. The Stainless TrashScreen™ is also available for Full Trash Capture requirements or to target special solid pollutants of concern that can evade typical stormwater trash screens and outlet protection systems. Please visit our Spec-a-SNOUT tool on the website to size a SNOUT for your application or contact a BMP application engineer for assistance.