Fig. 2From: Cultivation of lipid-producing microalgae in struvite-precipitated liquid digestate for biodiesel productionEffect of Mg2+ and PO43− sources on NH4+-N removal rate and salinity (NH4+:Mg2+:PO43− molar ratios at 1:1.2:1.2, the stirring was stopped as soon as the pH reached to 9.0). Errors bars show standard deviation (n = 3). Different letters indicate a significant difference at p < 0.05Back to article page