Water which flows from the apartment site (i.e. runoff from the terraces and overflow from the roof water tanks) is stored within a primary detention tank. The function of this tank is to provide short term storage in order to capture the runoff from the site during the storm event. The water in this tank is then pumped by the “primary pump” in batches to the bioretention planter bed at street level.
The primary transfer pump is controlled via Biofilta specialised pump logic from the central Biofilta panel. Water is pumped from the primary tank to our bioretention planter bed.
The planter provides a secondary physical filtration to remove fine sediments and associated bound heavy metals. The planter also biologically removes soluble nutrients from the stormwater via the plant root biofilms and microbes. Water is pumped from the primary tank to the planter bed at a controller rate to ensure that there is a “dose” and “rest” regime. This regime is crucial to ensure the health of plants & biofilms as well as ensure treatment efficiency.
Water which flows from the Biofilta bioretention planter is stored within the recirculation [retention] tank. Water within the recirculation tank is used to recirculate water back to the planter during dry periods. Water which exceeds the capacity of the recirculation tank flows to the street stormwater drainage as secondary treated stormwater.