In:
Journal of Environmental Quality, Wiley, Vol. 48, No. 3 ( 2019-05), p. 746-754
Abstract:
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 (HCO 3 , 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 CaCl 2 or MgCl 2 (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 HCO 3 /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 HCO 3 /Na membranes was correlated to plant P use in the acid soil, whereas the amount of P extracted by HCO 3 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 HCO 3 /Na membranes extract diffusible and noncrystalline P from SSA products. Combined HCO 3 /Na membranes extract P from stanfieldite in MgCl 2 –treated SSA products. Hydrogen‐saturated membranes solubilized most of the P present in SSA products. Blending CaCl 2 –treated SSA with KCl does not affect the amounts of extractable P.
Type of Medium:
Online Resource
ISSN:
0047-2425
,
1537-2537
DOI:
10.2134/jeq2018.11.0394
Language:
English
Publisher:
Wiley
Publication Date:
2019
detail.hit.zdb_id:
120525-0
detail.hit.zdb_id:
2050469-X
Bookmarklink