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Recovery of ammonia nitrogen and magnesium as struvite from wastewaters in coal‐fired power plant
Author(s) -
Zhao Xiaodan,
Tu Chengqin,
Zhou Zhen,
Zhang Wei,
Ma Xu,
Yang Jiazhe
Publication year - 2019
Publication title -
asia‐pacific journal of chemical engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.348
H-Index - 35
eISSN - 1932-2143
pISSN - 1932-2135
DOI - 10.1002/apj.2355
Subject(s) - struvite , flue gas desulfurization , chemistry , wastewater , ammonia , nitrogen , magnesium , phosphorus , polyacrylamide , nuclear chemistry , inorganic chemistry , pulp and paper industry , environmental chemistry , environmental engineering , organic chemistry , environmental science , engineering , polymer chemistry
This paper describes a cost‐effective method for recovering ammonia nitrogen (NH 4 + ‐N) from regeneration wastewater by using magnesium recovered from flue‐gas desulfurization (FGD) wastewater in the same coal‐fired power plant. Mg 2+ 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 NH 4 + ‐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 NH 4 + ‐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.