title: Enhanced struvite recovery from wastewater using a novel cone-inserted fluidized bed reactor.
abstract: The feasibility of struvite recovery at low (12.5 mg/L) and high (120 mg/L) phosphorus concentrations was studied by constructing a novel fluidized bed reactor with cones (FBRwc) and without cones (FBRwoc). The crystallization process was continuously operated for 133 days under different hydraulic retention times (HRT = 1-10 hr), pH (7.5-10), and molar ratios of Mg/P (0.75-1.75), N/P (1-10) and Ca/Mg (0-2). The optimum operating conditions of HRT, pH, Mg/P and N/P molar ratios were found to be 2 hr, 9, 1.25, and 7.5, respectively. Under these optimum conditions, the phosphorus precipitation efficiencies of FBRwc were 93% for low and 98% for high phosphorus influent; however, the efficiencies were 78% and 81% for FBRwoc, respectively. Due to crystal losses at each junction (17%-31%), the crystal recovery efficiency of FBRwoc was relatively low (47%-65%) for both influent concentrations. However, the losses were minimal in FBRwc, which showed 75% and 92% crystal recovery for low and high phosphorus concentrations, respectively. At low calcium concentration, crystal chemical analysis showed the product to be pure struvite (> 99%). The scanning electron microscope and X-ray diffraction results further confirmed that the crystal recovered from FBRwc contained pure struvite, which could be considered a high quality fertilizer. Except HRT, all parameters (pH, Mg/P, N/P and Ca/Mg) were found to be influencing factors for FBRwc performance. Overall, inserting cones in each part of the reactor played a significant role in enhancing struvite recovery from a wide range of phosphorus-containing wastewater.
authors: UNEP-Tongji Institute of Environment for Sustainable Development, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China. Electronic address: awokeguadie@gmail.com.
authors: Awoke
authors: A
authors: Guadie
authors: State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China. Electronic address: siqingxia@gmail.com.
authors: Siqing
authors: S
authors: Xia
authors: State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
authors: Wei
authors: W
authors: Jiang
authors: State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
authors: Lijie
authors: L
authors: Zhou
authors: State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China; Key Laboratory of Yangtze River Water Environment, Ministry of Education, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China. Electronic address: zhiqiang@tongji.edu.cn.
authors: Zhiqiang
authors: Z
authors: Zhang
authors: Department of Civil and Environmental Engineering, University of California, Berkeley, 629 Davis Hall #1710, Berkeley, CA 94720-1710, USA.
authors: Slawomir W
authors: SW
authors: Hermanowicz
authors: State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
authors: Xiaoyin
authors: X
authors: Xu
authors: State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
authors: Shuang
authors: S
authors: Shen
mesh_terms: D019149:Bioreactors; D002118:Calcium / Q000737:chemistry; D003460:Crystallization; D008274:Magnesium / Q000737:chemistry; D017616:Magnesium Compounds / Q000302:isolation & purification*; D009584:Nitrogen / Q000737:chemistry; D010710:Phosphates / Q000302:isolation & purification*; D010758:Phosphorus / Q000737:chemistry / Q000302:isolation & purification; D000069877:Struvite; D062065:Wastewater / Q000737:chemistry*
chemical_list: D002118:Calcium; D008274:Magnesium; D017616:Magnesium Compounds; D009584:Nitrogen; D010710:Phosphates; D010758:Phosphorus; D000069877:Struvite; D062065:Wastewater
keywords: fluidized bed reactor; phosphorus; recovery; struvite; wastewater