The unique environmental conditions in microalgal cultures may result in signifi­cant losses of nutrients from wastewater. In microalgal cultures, pH is high due to photosynthetic depletion of carbon dioxide (CO2) from the culture medium, and this may result in volatilization of ammonia or precipitation of P. In concentrated wastewaters such as animal manure, N is often present as ammonium. When pH is high, ammonium is converted to free ammonia and escaped as a gas from the culture medium through volatilization. Volatilization of ammonia can be significant in open algal ponds used for wastewater treatment, particularly when water tem­peratures are high (Garcia et al. 2000); this not only results in losses of N, but also causes eutrophication in the surrounding landscape through N deposition. However, maintaining the pH of the culture medium at 8 by addition of CO2 is effective to prevent ammonia volatilization (Park et al. 2011b). At a high pH, phosphate can also precipitate as calcium phosphates (when Ca concentrations are high; Beuckels et al. (2013) or as struvite when ammonium and magnesium (Mg) concentrations are high. Phosphate precipitation can result in significant losses of P from the wastewater (e. g., Lodi et al. 2003), causing additional turbidity in medium and reducing microalgal production (Belay 1997).