Pilot Research on Nutrient Removal with CO2 Supplemented Algal High Rate Ponds

A concept for achieving biological nutrient removal in high rate algal ponds supplemented with CO2-rich flue gas is under development, including small-scale pilot work described herein. The potential advantages of such an Algal Nutrient Removal (ANR) system compared to conventional mechanical treatment technologies, such as activated sludge, include lower capital and operating costs, a lower energy intensity, and the ability to recover fixed nitrogen for reuse as opposed to nitrification-denitrification. The disadvantages are the relatively large land use of ANR systems, the seasonality of treatment in temperate climates, and the need to dispose of or reuse nutrient-rich biomass (also listed as an advantage above). Pilot high rate ponds (3 m2 each) were used to treat clarified domestic wastewater in central, coastal California, with the objective of quantifying the ability of the ponds to produce microalgae and remove BOD and nitrogen.