Effects of Chlorella vulgaris on phosphorus release from ferric phosphate sediment by consecutive cultivations

Iron phosphate (Fe-P) is a main phosphorus storage form, especially in phosphorus-polluted environments. The re-release of Fe-P is a problematic result during microalgal remediation. In this study, pre-incubated was cultured in a BG-11 culture medium with different amounts of Fe-P. The effects of Fe-P re-release on biomass, flocculation and removal of PO were investigated. The results indicated that can promote the dissolution and release of Fe-P when the pH is 7, and the amount of Fe-P (ΔQ) released in 200 ml water reaches 0.055-0.45 mg d under a concentration of 5.6 × 10 -8 × 10 cells ml . The growth of was inhibited because of the flocculation behaviour of Fe in the release stage, which is associated with a specific growth rate of 0.3-0.4 d and a phosphorus removal rate below 30%. However, this process, in the long term, indicates a favourable transformation in which Fe-P becomes bioavailable under the action of . Microalgae outbreaks may be triggered by persistent interactions between Fe-P and . This study provides an important reference for the application of in a Fe-P-rich environment.