A Comparison of Heterogeneous/Homogeneous Crystallization for Phosphate Recovery from Biosolids. (1st September 2018)

• Record Type: Journal Article
• Authors: Lin, Nan‐Hung; Hsieh, Yung‐Hsu; Chuang, Shun‐Hsing; Wu, Chun‐Hao; Huang, Yao‐Hui
• Is Part Of: Water environment research. Volume 90:Number 9(2018)
• Page Start: 783
• Page End: 789
• Publication Date: 2018-09-01
• Subjects: crystallization -- heterogeneous -- homogeneous -- phosphorus -- magnesium ammonia phosphate (MAP); Water quality management -- Periodicals; Water -- Purification -- Periodicals; Water -- Pollution -- Periodicals; Water -- Pollution; Water -- Purification; Water quality management; Sewage; Water Pollution; Periodicals; Electronic journals; Periodicals; 628.16
• DOI: 10.2175/106143017X15131012153211
• Languages: English
• ISSNs: 1061-4303

Abstract

Abstract : In this study, a fluidized bed reactor was used to compare heterogeneous and homogeneous crystallization for recovering magnesium ammonia phosphate (MAP) from the dewatering filtrate at a municipal water resource recovery facility. Investigating the factors affecting crystallization revealed that pH exerted a greater effect than the Mg/P molar ratio. The results of a heterogeneous crystallization experiment showed that removal efficiency of phosphate (RP%) and crystal efficiency of phosphate (CP%) were 68% and 66%, respectively, at a PO4 ‐P concentration of 200 mg/L, pH of 8.0, and Mg/P molar ratio of 1.0 for 3 h. The reaction rate of heterogeneous crystallization was markedly higher than that of homogeneous crystallization. Those pellets produced through the heterogeneous crystallization exhibited a dense surface (particle size 0.5‐1.0 mm; water content 8.7%). Through scanning electron microscopy (SEM), energy dispersive x‐ray spectroscopy (EDS), and X‐ray diffraction (XRD) examination, the crystallized patterns of the needle‐shaped pellets were identified as MgNH4 PO4 ·6H2 O.