Bioresource Technology 2013-09-01

A kinetic study of struvite precipitation recycling technology with NaOH/Mg(OH)2 addition.

Rongtai Yu, Hongqiang Ren, Yanru Wang, Lili Ding, Jingji Geng, Ke Xu, Yan Zhang

Index: Bioresour. Technol. 143 , 519-24, (2013)

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Abstract

Struvite precipitation recycling technology is received wide attention in removal ammonium and phosphate out of wastewater. While past study focused on process efficiency, and less on kinetics. The kinetic study is essential for the design and optimization in the application of struvite precipitation recycling technology. The kinetics of struvite with NaOH/Mg(OH)2 addition were studied by thermogravimetry analysis with three rates (5, 10, 20 °C/min), using Friedman method and Ozawa-Flynn-Wall method, respectively. Degradation process of struvite with NaOH/Mg(OH)2 addition was three steps. The stripping of ammonia from struvite was mainly occurred at the first step. In the first step, the activation energy was about 70 kJ/mol, which has gradually declined as the reaction progress. By model fitting studies, the proper mechanism function for struvite decomposition process with NaOH/Mg(OH)2 addition was revealed. The mechanism function was f(α)=α(α)-(1-α)(n), a Prout-Tompkins nth order (Bna) model.Copyright © 2013 Elsevier Ltd. All rights reserved.