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The measurement of magnesium: A possible key to struvite production and process control


Forrest, AL and Mavinic, DS and Koch, FA, The measurement of magnesium: A possible key to struvite production and process control, Environmental Technology, 29, (6) pp. 603-612. ISSN 0959-3330 (2008) [Refereed Article]

DOI: doi:10.1080/09593330801984365


Struvite, a crystalline structure comprised of ions of magnesium (Mg2+), ammonium (NH4-N) and phosphate (PO4-P), is commonly encountered in wastewater treatment plants (WWTPs) through struvite encrustation. The gradual growth of this crystal can lead to high maintenance costs, due to downtime and replacement parts. Several struvite recovery unit processes have been developed in an effort to reduce this problem, through the preferential removal of the constituent ions (Mg2+, NH4-N, and PO4-P) upstream of problem areas (e.g. anaerobic digester supernatants). One of the key elements of process control for these systems is accurately determining the constituent concentrations. Although a wide variety of measurement techniques exist for both NH4-N and PO4-P, the presence of PO4-P interferes with the measurement of Mg2+. Ion selective electrodes (ISEs) were tested on wastewater samples to determine Mg2+ concentrations. It was found that the two ISE tested produced unreliable results, as they both proved non-specific to Mg2+. A modification, using polyaluminum chloride (PAC), was developed to remove the interference of phosphates from the colorimetric technique. It was found to produce reliable results within 10% of those results predicted by atomic absorption. The resulting technique averaged about 10 minutes per sample and could be conducted inexpensively at a laboratory facility at WWTPs. © Taylor & Francis, 2008.

Item Details

Item Type:Refereed Article
Keywords:Ion selective electrodes; Magnesium; Phosphate; Struvite; Wastewater; aluminum chloride; ammonia; magnesium; phosphate; polyaluminum chloride; struvite; Concentration (process); Electrodes; Magnesium; Process control; Wastewater treatment; magnesium
Research Division:Engineering
Research Group:Maritime engineering
Research Field:Maritime engineering not elsewhere classified
Objective Division:Environmental Management
Objective Group:Other environmental management
Objective Field:Other environmental management not elsewhere classified
UTAS Author:Forrest, AL (Dr Alexander Forrest)
ID Code:82347
Year Published:2008
Web of Science® Times Cited:3
Deposited By:NC Maritime Engineering and Hydrodynamics
Deposited On:2013-01-25
Last Modified:2014-02-21

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