title: Recycled Products from Municipal Wastewater: Composition and Effects on Phosphorus Mobility in a Sandy Soil.
abstract: Recycled products from wastewater may contain high concentrations of phosphorus (P) and are thus promising alternative fertilizers. However, to better predict their P fertilizer efficiency and potential for P leaching, investigations on P forms and P mobility in soil are essential. In this study, different recycled products-an untreated sewage sludge ash (SSA), an HSO-digested SSA, four thermochemically treated SSAs (two Mg-SSAs and two Ca-SSAs), and struvite-were investigated using a combination of wet chemical methods and P K-edge X-ray absorption near-edge structure (XANES) spectroscopy concerning their composition and their effects on P sorption in a sandy soil in comparison to triple superphosphate. Most of the P in the SSAs was associated with Ca in stable P fractions. The lowest P values in labile fractions (HO-P, NaHCO-P) were found for the untreated SSA and struvite. However, the addition of struvite resulted in an immediate increase in the bioavailable P fractions and the degree of P saturation in soil after only 1 d of incubation. This suggests a high P fertilizer potential for struvite but also a risk of P losses. Among the SSAs, the two Mg-SSAs increased the bioavailable P fractions in soil the most, whereas the lowest values were measured after application of the untreated SSA. Our results demonstrate that chemical analyses of recycled P products may involve the risk of misjudging the fertilizer quality when performed alone, without considering the behavior of these products in soil.
authors.forename: Telse
authors.initials: T
authors.lastname: Vogel
authors.forename: Jens
authors.initials: J
authors.lastname: Kruse
authors.forename: Nina
authors.initials: N
authors.lastname: Siebers
authors.forename: Michael
authors.initials: M
authors.lastname: Nelles
authors.forename: Bettina
authors.initials: B
authors.lastname: Eichler-Löbermann
mesh_terms: D005308:Fertilizers; D010758:Phosphorus / Q000737:chemistry*; D012722:Sewage; D012987:Soil; D062065:Wastewater
chemical_list: D005308:Fertilizers; D010758:Phosphorus; D012722:Sewage; D012987:Soil; D062065:Wastewater