Struvite precipitation by the dissolved CO 2 degasification technique: Impact of the airflow rate and pH

Abstract

In the present work, struvite precipitation was provoked by the dissolved CO 2 degasification technique where precipitation occurred following the degassing of the CO 2 by atmospheric air. The impact of the airflow rate and initial solution pH on struvite precipitation were assessed. For initial solution pH < 6.5, no precipitation was observed. For initial solution pH > 6.5, the phosphorus removal through struvite precipitation could be improved by increasing the airflow rate up to 25 L min −1, or by increasing the initial pH for higher airflow rates. Compared to traditional techniques of struvite precipitation such as stirring and aeration, the dissolved CO 2 degasification technique is promising since a high amount of phosphorus (∼78%) could be removed at relatively short experiment time.