1 research outputs found
Phosphorus Fate and Dynamics in Greywater Biofiltration Systems
Phosphorus,
a critical environmental pollutant, is effectively
removed from stormwater by biofiltration systems, mainly via sedimentation
and straining. However, the fate of dissolved inflow phosphorus concentrations
in these systems is unknown. Given the growing interest in using biofiltration
systems to treat other polluted waters, for example greywater, such
an understanding is imperative to optimize designs for successful
long-term performance. A mass balance method and a radiotracer, <sup>32</sup>P (as H<sub>3</sub>PO<sub>4</sub>), were used to investigate
the partitioning of phosphorus (concentrations of 2.5–3.5 mg/L,
>80% was in dissolved inorganic form) between the various biofilter
components at the laboratory scale. Planted columns maintained a phosphorus
removal efficiency of >95% over the 15-week study period. Plant
storage
was found to be the dominant phosphorus sink (64% on average). Approximately
60% of the phosphorus retained in the filter media was recovered in
the top 0–6 cm. The <sup>32</sup>P tracer results indicate
that adsorption is the immediate primary fate of dissolved phosphorus
in the system (up to 57% of input P). Plant assimilation occurs at
other times, potentially liberating sorption sites for processing
of subsequent incoming phosphorus. Plants with high nutrient uptake
capacities and the ability to efficiently extract soil phosphorus,
for example <i>Carex appressa</i>, are, thus, recommended
for use in greywater biofilters