| Autor: |
Nanzer, Simone1, Oberson, Astrid1, Eggenberger, Urs2, Frossard, Emmanuel1 emmanuel.frossard@usys.ethz.ch |
| Předmět: |
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| Zdroj: |
Journal of Environmental Quality. May2019, Vol. 48 Issue 3, p746-754. 9p. |
| Abstrakt: |
Thermochemical treatments allow production of sewage sludge ash (SSA) rich in P and low in heavy metals, which could be recycled in agriculture. Our objective was to quantify P release from SSA using ion sink assays and to relate these results to P speciation in SSA and plant P uptake. Anion and cation exchange membranes saturated with different counterions (HCO3, Na, and H) were used to create a gradient in pH, P, or cation concentration between SSA particles and the surrounding solution. Phosphorus speciation in SSA was assessed using X‐ray powder diffraction, and plant P uptake was determined in a pot experiment with an acidic and a neutral soil. Four SSA products were investigated: a SSA thermochemically treated with CaCl2 or MgCl2 (SSA Ca/Mg), a SSA blended with KCl, and a SSA blended with KCl and triple superphosphate (TSP) to obtain a marketable 12–20 P–K fertilizer. The H membranes dissolved all P species present in SSA. Combined HCO3/Na membranes extracted diffusible P and noncrystalline P from SSA Ca/Mg and stanfieldite from SSA Mg. Blending with KCl hardly changed P release from SSA, whereas blending with TSP masked P release. The amount of P extracted from SSA by combined HCO3/Na membranes was correlated to plant P use in the acid soil, whereas the amount of P extracted by HCO3 membranes alone was correlated to P use in the neutral soil. In conclusion, the ion sink assays delivered information on P release that was related to both SSA mineralogy and P use by plants. Core Ideas: Ion exchange membranes are proposed to predict P release from sewage sludge ash (SSA) products.Combined HCO3/Na membranes extract diffusible and noncrystalline P from SSA products.Combined HCO3/Na membranes extract P from stanfieldite in MgCl2–treated SSA products.Hydrogen‐saturated membranes solubilized most of the P present in SSA products.Blending CaCl2–treated SSA with KCl does not affect the amounts of extractable P. [ABSTRACT FROM AUTHOR] |
| Databáze: |
GreenFILE |
| Externí odkaz: |
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