Specifications
Dimensions
Width
48"
Depth
50"
Height
100"
Flow Capacity
Max Treated
15 gpm
Ideal Treatment
8-10 gpm
Overflow
50 gpm
1st Stage
275-gallon
10-oz geotextile
2nd Filter
Open Cell Filter Cloth
2nd Stage
12-gallon
Open Cell Filter Cloth
Filtered Collection
Launder
BioChar Mix 2
16 ft3
Biochar/ Sand/ Topsoil
10 ft3
Organic Drought Tolerant Sedges/ Rushes
System Details
Our 275 BioDown Rain Garden is available in 1 size – 275-gallon.
The 275 BioDown Rain Garden has a flow capacity that can reach up to 15GPM.
The Gullywasher 275 BioDOWN Biofilters are a passive stormwater purification filter able to remove metals and other contaminants from stormwater.
The main Filter Box container is a repurposed 275-gallon chemical tote, only used once and solely with compatible chemicals for stormwater. A 12-gallon filter box complete with a 10 oz geotextile filter bag is used for separating incoming large suspended solids from stormwater.
Filtered stormwater gravity flows out of the filter box and into two Influent Launders– one on either side of the filter box. These allow for equal distribution of the stormwater onto the grated filter screen.
The first media level will be the Gullywasher Special Biochar/Sand/Topsoil Mix. This is an engineered plant-soil of which the biochar will act as water storage capillaries regulating the soil moisture content in conjunction with the microcoria content in the soil, the sand will provide adequate porosity for the plants’ roots to grow in and the topsoil mix will be made without any excess nutrients added (stormwater contaminants).
As an option, Gullywasher can provide Locally Available Organic Sedges and Thrushes and plant them into the rain garden biofilters.
The second media level will be filter screened consisting of our Gullywasher Biochar Mix 2 Media. This is an engineered filter media designed to remove metals (dissolved & total), BOD and COD. This media also has a minor ability in removing nutrients.
The third and last filter screened media-level will be our Gullywasher Filter Grade Quartz Gravel. This is a filter-grade gravel with specified round corners and quartz (non-metal) content.
Once the stormwater flows out of the filter box outlet, it flows up through a Gullywasher Engineered Discharge Outlet Piping before exiting. This forces the stormwater from entirely flowing from a gravity push to that of a partial mass balance displacement. This provides the stormwater ample time to have the treatment dynamic contacts necessary to maximize metals removal.
We can utilize virtually any filter media; however, the lab test results are focused solely on the use of a filter-grade biochar. Third-party lab results have shown 99.7% removal of metals over a year’s service.
