title: Effect of humic substances on phosphorus removal by struvite precipitation.
abstract: Humic substances (HS) are a major fraction of dissolved organic matters in wastewater. The effect of HS on phosphorus removal by struvite precipitation was investigated using synthetic wastewater under different initial pH values, Mg/P molar ratios and HS concentrations. The composition, morphology and thermal properties of harvested precipitates were analyzed by X-ray diffraction (XRD), scanning electron microscope (SEM) and thermo-gravimetric analysis (TGA), respectively. It showed that inhibition effect of HS reached its maximum value of 48.9% at pH 8.0, and decreased to below 10% at pH>9.0. The increase of Mg/P ratio enhanced phosphorus removal efficiency, and thus reduced the influence of HS on struvite precipitation. At pH 9.0, the inhibitory effect of initial HS concentration matched the modified Monod model with half maximum inhibition concentration of 356mgL(-1), and 29% HS was removed in conjunction with struvite crystallisation. XRD analysis revealed that the crystal form of struvite precipitates was changed in the presence of HS. The morphology of harvested struvite was transformed from prismatic to pyramid owing to the coprecipitation of HS on crystal surface. TGA results revealed that the presence of HS could compromise struvite purity.
authors.affiliation: College of Environmental and Chemical Engineering, Shanghai University of Electric Power, Shanghai 200090, China; College of Environmental and Chemical Engineering, Shanghai University of Electric Power, Changyang Rd #2588, Shanghai 200090, China. Electronic address: zhouzhen@shiep.edu.cn.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Zhou
authors.affiliation: College of Environmental and Chemical Engineering, Shanghai University of Electric Power, Shanghai 200090, China; College of Environmental and Chemical Engineering, Shanghai University of Electric Power, Changyang Rd #2588, Shanghai 200090, China.
authors.forename: Dalong
authors.initials: D
authors.lastname: Hu
authors.affiliation: College of Environmental and Chemical Engineering, Shanghai University of Electric Power, Shanghai 200090, China; College of Environmental and Chemical Engineering, Shanghai University of Electric Power, Changyang Rd #2588, Shanghai 200090, China.
authors.forename: Weichao
authors.initials: W
authors.lastname: Ren
authors.affiliation: College of Environmental and Chemical Engineering, Shanghai University of Electric Power, Shanghai 200090, China; College of Environmental and Chemical Engineering, Shanghai University of Electric Power, Changyang Rd #2588, Shanghai 200090, China.
authors.forename: Yuzeng
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: College of Environmental and Chemical Engineering, Shanghai University of Electric Power, Shanghai 200090, China; College of Environmental and Chemical Engineering, Shanghai University of Electric Power, Changyang Rd #2588, Shanghai 200090, China.
authors.forename: Lu-Man
authors.initials: LM
authors.lastname: Jiang
authors.affiliation: College of Environmental and Chemical Engineering, Shanghai University of Electric Power, Shanghai 200090, China; College of Environmental and Chemical Engineering, Shanghai University of Electric Power, Changyang Rd #2588, Shanghai 200090, China.
authors.forename: Luochun
authors.initials: L
authors.lastname: Wang
mesh_terms: D011232:Chemical Precipitation; D003460:Crystallization; D006812:Humic Substances / Q000032:analysis*; D006863:Hydrogen-Ion Concentration; D017616:Magnesium Compounds / Q000737:chemistry / Q000302:isolation & purification*; D008855:Microscopy, Electron, Scanning; D010710:Phosphates / Q000737:chemistry / Q000302:isolation & purification*; D010758:Phosphorus / Q000737:chemistry / Q000302:isolation & purification*; D000069877:Struvite; D013499:Surface Properties; D062065:Wastewater / Q000737:chemistry*; D018508:Water Purification / Q000379:methods*; D014961:X-Ray Diffraction
chemical_list: D006812:Humic Substances; D017616:Magnesium Compounds; D010710:Phosphates; D010758:Phosphorus; D000069877:Struvite; D062065:Wastewater
keywords: Humic substances; Phosphorus; Precipitation; Struvite; Wastewater