Uses of the reject brine from inland desalination for fish farming,
Spirulina cultivation, and irrigation of forage shrub and crops
algae scrubbers have shown promise for recovering phosphorus (P), no detailed studies have been completed
to research conditions for maximum total P (TP) removal. Previous studies have suggested that
faster flow rates and pulsed inflow conditions are necessary for high biomass production. Studies have
also theorized thatthe calcium-phosphorus (Ca-P) co-precipitation is the driving TP removal mechanism.
As a result, the goal of this study was to determine the effect of the following operating parameters on
TP removal: (1) flow rate, (2) pulsed versus constant inflow, (3) calcium addition to inflow water, (4) calcium
seed addition, and (5) 24-h versus 12-h operation. Results show that 12-h operation significantly
increases TP removal in algae scrubber systems from an average of 24 g/m2/y to 52 g/m2/y. The high TP
removal rate can be attributed to the stabilization of Ca-P minerals during 12-h operation. Algal photosynthesis
increases daytime pH values (9–9.5) driving Ca-P co-precipitation, and 12-h operation prevents
these minerals from re-dissolving at night as the pH decreases back to neutral (7–7.5). The maintenance
of an algal seed on the scrubbers significantly decreased the amount of time necessary between harvests,
increasing algal productivity