Recovery of ammonia nitrogen and magnesium as struvite from wastewaters in coal‐fired power plant

This paper describes a cost‐effective method for recovering ammonia nitrogen (NH4+‐N) from regeneration wastewater by using magnesium recovered from flue‐gas desulfurization (FGD) wastewater in the same coal‐fired power plant. Mg2+ was efficiently removed from FGD wastewater at pH of 11, and the set...

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Bibliographic Details
Published in:Asia-Pacific journal of chemical engineering 2019-09, Vol.14 (5), p.n/a
Main Authors: Zhao, Xiaodan, Tu, Chengqin, Zhou, Zhen, Zhang, Wei, Ma, Xu, Yang, Jiazhe
Format: Article
Language:English
Subjects:
ammonia nitrogen
magnesium
power plant
recovery
struvite
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Summary:This paper describes a cost‐effective method for recovering ammonia nitrogen (NH4+‐N) from regeneration wastewater by using magnesium recovered from flue‐gas desulfurization (FGD) wastewater in the same coal‐fired power plant. Mg2+ was efficiently removed from FGD wastewater at pH of 11, and the settling performance of Mg (OH)2 was evidently improved by adding anionic polyacrylamide and crystal seed. For NH4+‐N removal optimization by response surface methodology, the results indicated that the molar ratio of phosphorus to nitrogen (P/N) was the more dominant parameter, and the optimum conditions were predicted at Mg/N of 1.1 and P/N of 0.7. At the optimum conditions, the predicted data of NH4+‐N removal efficiency (NRE) and residue phosphorus were 71.41% and 21.90 mg/L, and actual experimental data were 72.12% and 19.60 mg/L. The inhibitory effect of NaCl concentration on NRE matches the modified Monod model with half inhibition concentration of 89.01 g/L. Morphologic analysis confirmed that salinity inhibited the formation and growth of struvite crystals.
ISSN:1932-2135
1932-2143
DOI:10.1002/apj.2355