title: Evaluation of the role of inherent Ca(2+) in phosphorus removal from wastewater system.
abstract: The role of inherent Ca(2+) in phosphorus removal from wastewater was evaluated by batch tests. Precipitates were characterized by an X-ray diffractometer (XRD), Fourier transform infrared spectrophotometer (FT-IR) and scanning electron microscope with an energy dispersive spectrometer (EDS) system. Effects of inherent Ca(2+) on phosphorus removal through basic oxygen furnace slag (BOFS) were also analyzed. The results show that upon adjusting the pH to higher than 7.0, inherent Ca(2+) can remove phosphorus from wastewater and form Ca-P precipitates. Residual phosphorus exhibited a linear decreasing trend with increasing the pH from 7.0 to 10.0 and then remained unchanged at higher pH than 10.0. EDS determined that the precipitates contained the elements Ca, P and O. FT-IR spectra demonstrated that the functional groups of precipitates involved PO4(3-), OH(-) and CO3(2-). XRD indicated that the precipitates may consist of CaCO3 and some Ca-P phosphates such as CaHPO4, Ca4H(PO4)3, Ca3(PO4)2, and Ca5(PO4)3(OH). During the removal process of phosphorus by BOFS, due to the presence of inherent Ca(2+) in wastewater, the removal efficiency and rate of phosphorus increased by 15.5% and by a factor of about 3.0, respectively.
authors.affiliation: School of Metallurgy, Northeastern University, Shenyang 110819, China E-mail: hanch@smm.neu.edu.cn.
authors.forename: Chong
authors.initials: C
authors.lastname: Han
authors.affiliation: School of Metallurgy, Northeastern University, Shenyang 110819, China E-mail: hanch@smm.neu.edu.cn.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Wang
authors.affiliation: School of Metallurgy, Northeastern University, Shenyang 110819, China E-mail: hanch@smm.neu.edu.cn.
authors.forename: Qianqian
authors.initials: Q
authors.lastname: Wu
authors.affiliation: School of Metallurgy, Northeastern University, Shenyang 110819, China E-mail: hanch@smm.neu.edu.cn.
authors.forename: Wangjin
authors.initials: W
authors.lastname: Yang
authors.affiliation: School of Metallurgy, Northeastern University, Shenyang 110819, China E-mail: hanch@smm.neu.edu.cn.
authors.forename: He
authors.initials: H
authors.lastname: Yang
authors.affiliation: School of Metallurgy, Northeastern University, Shenyang 110819, China E-mail: hanch@smm.neu.edu.cn.
authors.forename: Xiangxin
authors.initials: X
authors.lastname: Xue
mesh_terms: D002118:Calcium / Q000737:chemistry*; D002119:Calcium Carbonate / Q000737:chemistry; D010100:Oxygen; D010710:Phosphates / Q000737:chemistry*; D010758:Phosphorus / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D064091:Waste Disposal Facilities; D062065:Wastewater / Q000737:chemistry*; D018508:Water Purification
chemical_list: D002118:Calcium; D002119:Calcium Carbonate; D010100:Oxygen; D010710:Phosphates; D010758:Phosphorus; D062065:Wastewater