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Carbonell, G., Pro, J., Gómez, N., Babín, M.M., Fernández, C., Alonso, E. and Tarazona, J.V. (2009) Sewage Sludge Applied to Agricultural Soil: Ecotoxicological Effects on Representative Soil Organisms. Ecotoxicology and Environmental Safety, 72, 1309-1319.
http://dx.doi.org/10.1016/j.ecoenv.2009.01.007

has been cited by the following article:

  • TITLE: Recovery and Upgrading of Phosphorus from Digested Sewage Sludge as MAP by Physical Separation Techniques

    AUTHORS: Tsuyoshi Hirajima, Takao Hagino, Mia Kose, Mohsen Farahat, Keiko Sasaki

    KEYWORDS: Phosphorus Recovery, Sewage Sludge, MAP, Physical Separation, Removal of Heavy Metals

    JOURNAL NAME: Journal of Environmental Protection, Vol.7 No.6, May 12, 2016

    ABSTRACT: Physical separation apparatuses; a vibrating screen, a 4-inch hydrocyclone and a Multi-Gravity Separator (MGS) were used to recover phosphorus as MAP (magnesium ammonium phosphate, MgNH4PO4.6H2O) from anaerobic digested sludge of two sewage-treatment plants A and B. For plant A, the MAP grade increased from 0.08% to 88.9% with 90.4% recovery and for plant B, the grade increased from 0.11% to 73.8 with 93.2% recovery. The collected MAP products containing impurities such as organic materials and heavy metals were further upgraded through dry and wet magnetic separation tests at different magnetic flux densities. A dry magnetic separator was tested on both MAP products (MAP-A and MAP-B), while the wet magnetic separation process was exclusively experimented for the removal of impurities from MAP-B. Feed samples, as well as magnetic and nonmagnetic products were analyzed by absorption spectroscopy, XRD, ICP-AES, polarizing microscope observation, and SEM-EDX. The grade of MAP products could be improved by about 4% - 9% after magnetic separation (the most appropriate magnetic force being 15,000 Gauss). During both dry and wet magnetic separation processes, not only heavy metals have been removed, but also nonmagnetic constituents like Al, Ba, and Ca. This may be attributed to the attachment of fine magnetic particles on the nonmagnetic surfaces, rendering them magnetic properties.