Phosphorus Removal Rates
Table 3 shows a summary of the bulk chemistry and the key compaction parameters of VOIDSPACE aggregates for use with PaveDrain Systems.
VOIDSPACE also has the ability to rapidly remove dissolved phosphorus from water in the time frames associated with stormwater storage in underground vaults (up to 72 hours). Duplicate equilibration experiments modeled after EPA 1316 using VOIDSPACE Aggregates (VS1 and VS2) and stock solutions with 1, 5 and 10 mg/L ortho-PO4 (most storm water has < 1 mg/L) for contact times between 5 minutes and 72 hours showed that the VOIDSPACE aggregates achieved very high removal rates of phosphorous, as shown in Figure 3.
VOIDSPACE fines (VSF; <3/8 inches) result from the aggregate crushing process to make VS1 and VS2 are also available and may have significant advantages when it comes to phosphorus removal when placed at strategic locations in the PaveDrain System profile. Figure 3 shows that VSF was associated with almost complete removal of ortho-PO4 for all contact times tested.