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Combining magnesium ammonium phosphate precipitation with membrane processes for ammonia removal from methanogenic leachates
Publikationstyp
Journal Article
Date Issued
2016-09-01
TORE-URI
Journal
Volume
30
Issue
3-4
Start Page
218
End Page
226
Citation
Water and Environment Journal 3-4 (30): 218-226 (2016-09-01)
Publisher DOI
Scopus ID
Chemical precipitation of ammonia as magnesium ammonium phosphate (MAP) from methanogenic leachates can be a competitive alternative to biological ammonia removal. Potential for trading of the precipitate as a fertiliser defines the economics of the process. The precipitate from a landfill leachate often containing organics and heavy metals as impurities with unknown risks limits its possibility for agricultural use. This study combines MAP precipitation with membrane processes and investigates the influence of wastewater matrix, solution pH and dosage ratio of chemicals (Mg2+ : PO43−) on the precipitate purity through lab scale semibatch experiments. Under similar experimental conditions (pH 8.5 and 1 : 1 Mg2+ : PO43− molar dosage), the precipitates from raw leachate and nanofiltration (NF) permeate showed MAP contents of 65 and 90%, respectively, correspondingly with about 8300 and 1600 mg TOC/kgprecipitate. For precipitation from NF permeate, precipitation at pH 8.0 with 1 : 1 dosage ratio and pH 8.5 with 1 : 0.9 dosage ratio gave precipitates each with about 97% purity.
Subjects
chemical precipitation
magnesium ammonium phosphate
methanogenic landfill leachate
nanofiltration
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