During a recent StormFilter design, the question came up about whether a StormFilter cartridge system will permanently hold water. The unique design and orifice discharge disc at the base of each cartridge allows the chamber where the cartridges are installed to drain dry between rain events.
The Engineer also asked whether a false floor is required as other systems don’t use a false floor. With the StormFilter system, regardless of the cartridge size or media type, a false floor is always used. The false floor allows us to fix the underdrain manifold in place, create a safe and trip hazard free floor and more importantly eliminates a permanent water pool which essentially can be considered an anaerobic zone.
It can be considered similar to the wet sump GPT situation and hence the limit on accepted nutrient reduction. Permanent water and particulate nutrient loads in time result in dissolved nutrient load (leachate) which can be a problem for receiving water courses. Obviously we want to steer clear of this if at all possible.
The real benefit of not holding water is recognised when leachate is assessed as part of the product performance evaluation. This has been demonstrated time and time again during the StormFilter field assessments both in Australia and the US and forms an integral component of field testing protocols used today.
Please call us on 1300 354 722 for more information.