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Struvite Recovery from Swine Waste Biogas Digester Effluent through a Stainless Steel Device under Constant pH Conditions.

Authors :
PERERA, P.W. Anton
WU, Wei-Xiang
CHEN, Ying-Xu
HAN, Zhi-Ying
Source :
Biomedical & Environmental Sciences; Jun2009, Vol. 22 Issue 3, p201-209, 9p
Publication Year :
2009

Abstract

Objective: To investigate the struvite precipitation under constant and non-constant pH conditions and to test a stainless steel device under different operating regimes to maximize the recovery of struvite. Methods: The molar ratio of NH<subscript>4</subscript> <superscript>+</superscript>: Mg<superscript>2+</superscript>: PO<subscript>4</subscript> <superscript>3−</superscript> was adjusted to 1: 1.2: 1.2 and pH was elevated to 9.0. The absorbance measurement was used to trace the process of struvite crystallization. Wastewater and precipitate analysis was done by standard analytical methods. Results: The pH constant experiment reported a significantly higher struvite precipitation (24.6±0.86 g) than the non-constant pH experiment (19.8±1.86 g). The SAR ranged from 5.6 to 8.2 g m<superscript>−2</superscript> h<superscript>−1</superscript> to 3.6-4.8 g m<superscript>−2</superscript> h<superscript>−1</superscript> in pH constant and non-constant experiments, respectively. The highest struvite deposit on the device was found in regime 3 followed by in regimes 2 and 4. The highest PO<subscript>4</subscript> <superscript>3-</superscript> (97.2%) and NH<subscript>4</subscript> <superscript>+</superscript> (71%) removal was reported in the R1 regime. None of the influent Cu<superscript>2+</superscript> or Zn<superscript>2+</superscript> was precipitated on the device. Conclusion: A higher struvite yield is evident in pH constant experiments. Moreover, the stainless steel device facilitates the isolation of heavy metal free pure (around 96%) struvite from swine waste biogas digester effluent contaminated with cu<superscript>2+</superscript> and Zn<superscript>2+</superscript> and the highest yield is attainable with the device operating at 50 rpm with agitation by a magnetic stirrer. [Copyright &y& Elsevier]

Details

Language :
English
ISSN :
08953988
Volume :
22
Issue :
3
Database :
Supplemental Index
Journal :
Biomedical & Environmental Sciences
Publication Type :
Academic Journal
Accession number :
43529983
Full Text :
https://doi.org/10.1016/S0895-3988(09)60046-5