Phosphorus Removal and Recovery in Novel Seed Crystal Media Filter
A seed crystal medium was developed from the powder steel slag and other material in order to carry out a novel method for phosphorus removal and recovery through the crystallization process. Continuous-flow fixed-bed column experiment was conducted to investigate the phosphorus removal capacity with low P concentration (10mg/L), and the influences of HRT, Ca/P ratio and pH on the treatment efficiency were also considered. It was observed that the P concentration of filter effluent was always lower than 0.5mg/L whether under the experimental condition of pH=7 and HRT=60 min or the condition of pH=7, HRT=30min and the Ca/P ratio = 1.5. With the HRT 30min, increasing pH to 7.5 and decreasing Ca/P ratio to 1, the P concentration of filter effluent was still lower than 0.5mg/L. The XRD analysis of the sediment obtained from the filter bed proved that product formed in the phosphorus removal process was Hydroxyapatite (HAP), illustrated that the crystallization occurred in the process of P-removal. The results of this study suggest that the fixed bed - phosphorus crystallization process with seed crystal media is a promising technique for phosphorus removal and recovery.
Y. B. Li and L. P. Qiu, "Phosphorus Removal and Recovery in Novel Seed Crystal Media Filter", Applied Mechanics and Materials, Vols. 90-93, pp. 2969-2972, 2011