TY - JOUR
T1 - Algae scrubbers for phosphorus removal in impaired waters
AU - Sindelar, Hugo R.
AU - Yap, Jake N.
AU - Boyer, Treavor H.
AU - Brown, Mark T.
N1 - Funding Information:
Gainesville Regional Utilities generously shared space at MSWRF for the construction of this project. The authors wish to thank the operators at MSWRF for assisting with sample collection and Julia Slayden, Alexandra Rozin, and Stephanie Ishii for help with sample processing. Taylor Bomarito and Sam Arden helped with design and construction of the algae scrubbers. Mihai Giurcanu provided statistical consulting for the project. This work was supported in part by the Everglades Foundation and the USGS WRRI Project ID 2011FL267B. The Everglades Foundation and the USGS have not officially endorsed this publication and the views expressed herein may not reflect the views of the Everglades Foundation or the USGS.
Publisher Copyright:
© 2015 Elsevier B.V.
PY - 2015/12/1
Y1 - 2015/12/1
N2 - Algae scrubbers are a developing technology used for nutrient removal from many different impaired waters, including: agricultural runoff, wastewater, and animal operation waste. Algae thrive in environments with high flow velocities, allowing treatment of large volumes of nutrient-rich water. This adaptation helps overcome space issues associated with other biological treatment systems. Although 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 that the 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 24g/m2/y to 52g/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.
AB - Algae scrubbers are a developing technology used for nutrient removal from many different impaired waters, including: agricultural runoff, wastewater, and animal operation waste. Algae thrive in environments with high flow velocities, allowing treatment of large volumes of nutrient-rich water. This adaptation helps overcome space issues associated with other biological treatment systems. Although 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 that the 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 24g/m2/y to 52g/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.
KW - Algae scrubber
KW - Biological treatment
KW - Calcium
KW - Co-precipitation
KW - Nutrient removal
KW - Phosphorus
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U2 - 10.1016/j.ecoleng.2015.09.002
DO - 10.1016/j.ecoleng.2015.09.002
M3 - Article
AN - SCOPUS:84945176646
SN - 0925-8574
VL - 85
SP - 144
EP - 158
JO - Ecological Engineering
JF - Ecological Engineering
ER -