Please use this identifier to cite or link to this item: http://hdl.handle.net/10397/2436
Title: Recovery of ammonium-nitrogen from landfill leachate as a multi-nutrient fertilizer
Authors: Li, XZ
Zhao, QL
Keywords: Landfill leachate
Ammonium-nitrogen
Precipitation
Crystallization
Magnesium ammonium phosphate (MAP)
Struvite and vegetables
Issue Date: May-2003
Publisher: Elsevier
Source: Ecological engineering, May 2003, v. 20, no. 2, p. 171-181 How to cite?
Journal: Ecological engineering 
Abstract: Leachates generated in Hong Kong landfill sites contain high strength of ammonium-nitrogen (NH??-N) in the range of 2000-5000 mg l??, which could be used to produce nitrogen-fertilizer. To recover the NH??-N from the leachate, a lab-scale study was performed to investigate the efficiency of magnesium ammonium phosphate (MAP) precipitation using three combinations of chemicals: MgCl??6H?O +Na?HPO??12H?O, MgO+85% H?PO? and MgSO??7H?O+Ca(H?PO?)?H?O. The results indicated that the NH??-N was recovered by 92, 36 and 70%, respectively, using the selected chemicals at pH 9.0 and a molar ratio of Mg:N:P=1:1:1. The MAP precipitate (MgNH?PO? .6H?O) as struvite was examined by scanning electron microscopy and the results showed that the MAP precipitate had a typical morphology of elongated tubular and short prismatic crystals. The MAP precipitate was also analyzed by energy dispersive spectroscopy and the analytical results indicated its composition of 4.9% N, 8.6% Mg and 16% P, which was similar to the standard struvite composition of 5.7% N, 9.9% Mg and 12.6% P. To investigate the fertility of the MAP precipitate, a set of pot trial tests was conducted. Four quick-growth vegetables, Chinese flowering cabbage (Brassica parachinensis ), Chinese chard (Brassica rapa var. chinensis ), water spinach (Ipomoea aquatica) and water convolvulus (Ipomea aquatica, I. reptans ), were planted in sandy clay (Red Earth) and the MAP precipitate was applied as a fertilizer. The germination and growth of the selected vegetables in the pots with MAP showed significantly greater rates than those in the pots without MAP as control tests. The experiment also demonstrated that over-dosing of about 2-8 times of MAP in the soil did not cause any problems with water spinach (Ipomoea aquatica) growth, due to its limited solubility in water. MAP application as a fertilizer did not result in more heavy metals in the vegetables than those from soil and model fertilizer, whereas the higher levels of P and Mg in the vegetables would stimulate vegetables¡¦ growth. This study confirmed the feasibility of recovering NH??-N from landfill leachate effectively by chemical precipitation, and also the feasibility of applying the MAP precipitate as a multi-nutrient fertilizer for vegetable growth.
URI: http://hdl.handle.net/10397/2436
ISSN: 0925-8574
DOI: 10.1016/S0925-8574(03)00012-0
Rights: Ecological Engineering ? 2003 Elsevier Science B. V. The journal web site is located at http://www.sciencedirect.com.
Appears in Collections:Journal/Magazine Article

Files in This Item:
File Description SizeFormat 
35.pdfPre-published version70.28 kBAdobe PDFView/Open
Access
View full-text via PolyU eLinks SFX Query
Show full item record

SCOPUSTM   
Citations

84
Last Week
0
Last month
Citations as of Feb 6, 2016

WEB OF SCIENCETM
Citations

75
Citations as of Feb 6, 2016

Page view(s)

559
Checked on Feb 7, 2016

Google ScholarTM
Citations

loading...

Altmetric



Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.