Phosphorus speciation and fertiliser performance characteristics: A comparison of waste recovered struvites from global sources

Abstract

Our immediate and future food security agenda requires sustainable phosphorus (P) management, and recovered P products such a struvite form part of the solution. Waste recovered struvite is generated from different waste streams and precipitation technologies. In this study, we compare P speciation and bioavailability of nine struvite products with traditional/granulated chemical fertilisers to investigate performance characteristics across soil types in the Irish ecoregion.Elemental-analysis/P-speciation of the struvites was examined by ICP-OES, 31 P solid state NMR, PXRD and P-solubility tests. The fertiliser dose effect and bioavailability of the different struvite products were tested in 4-week and 3-month rhizotron experiments with Lolium perenne. In addition to calculating plant-P offtake, bioavailability was assessed by Olsen-P and Diffusive-Gradients-in-Thin-Films (DGT). The struvites differed markedly in colour/appearance, texture, metal content and solubility. Struvites all had similar P-speciation, but minor impurity phases were detected. There was no significant difference between the struvite samples and triple-superphosphate (TSP) with respect to either plant growth performance or P-bioavailability. The struvite products are produced from different wastewater streams/processes, yet possess a uniformity in overall fertilising performance within our experiments. Encouragingly, no appreciable agronomic difference in terms of yield was observed between the struvite and chemical fertilisers, which provides further evidence in support of struvite as a sustainable alternative to mined rockphosphate derived products. Importantly the struvite samples analysed within this study contained both significantly fewer impurities than TSP and lower concentrations of toxic metals such as cadmium.

Electrochemically precipitated struvite effects on extractable nutrients compared with other fertilizer‐phosphorus sources

“…In the loam, SiL 1, and SiL 2 soils, M3-P concentrations at least numerically increased from the initial value and were similar among MAP, DAP, TSP, CPST, and ECST treatments (Figure 6). Despite the slower dissolution rate of the two struvite sources (i.e., ECST and CPST), similar P availability was observed among the struvite sources and MAP, DAP, and TSP, where a similar result has been reported in several previous studies (Cabeza et al, 2011;Hall et al, 2020;Katanda et al, 2016;Tallboys et al, 2016). In the SiCL soil, the change in M3-P concentrations was much more complex.…”

Acid-Induced Phosphorus Release from Hydrothermally Carbonized Sewage Sludge

“…Fang et al [34] suggested that pretreatment of ISSA with EDTA could remove heavy metals prior to acid leaching. However, it should be noted that the levels of heavy metals detected in this study were still well below the levels of impurities found in phosphate rock and commercial inorganic fertilizer such as TSP (triple super phosphate) [43]. Additionally, levels of Ni, Cr and Cd were even orders of magnitude higher in TSP compared to levels measured in this study [43].…”

“…However, it should be noted that the levels of heavy metals detected in this study were still well below the levels of impurities found in phosphate rock and commercial inorganic fertilizer such as TSP (triple super phosphate) [43]. Additionally, levels of Ni, Cr and Cd were even orders of magnitude higher in TSP compared to levels measured in this study [43]. is a promising route for P recovery from complex wastes residues.…”

Wastewater‐recovered struvite effects on total extractable phosphorus compared with other phosphorus sources

“…Phosphorus mobility and availability in soils are intrinsically determined by a specific soil's set of physical and chemical properties (Nascimento et al., 2018), which transform to some degree under flooded soil conditions and in the presence of plant roots. Thus, it is imperative that struvite × soil interactions not only be studied in upland, aerobic soil environments (Anderson et al., 2020; Hall et al., 2020), but also in lowland, flooded soil environments to evaluate struvite's potential use as a fertilizer P source across a wide range of crops, such as rice. Therefore, the objective of this study was to assess net changes in total P concentrations over time in water‐soluble (WS) and Mehlich‐3 (M3) extracts from varying soil textures (two silt loams and a silty clay loam) amended with a commercially available, wastewater‐recovered, chemically precipitated struvite (ST) source compared with other commercially available, conventional fertilizer P sources (monoammonium phosphate, MAP, and triple superphosphate, TSP) in a plant‐less soil incubation in saturated‐/flooded soil conditions.…”

“…Although several studies have examined struvite's fertilizer potential in potted‐plant and greenhouse studies (Ackerman et al., 2013; Bonvin et al., 2015; Gong et al., 2018; Hall et al., 2020; Hilt et al., 2016), little is known about struvite × soil × chemical × property interactions in fine‐textured, agricultural soils with a history of row‐cropping and no studies have examined struvite × soil interactions under flooded soil conditions. Phosphorus mobility and availability in soils are intrinsically determined by a specific soil's set of physical and chemical properties (Nascimento et al., 2018), which transform to some degree under flooded soil conditions and in the presence of plant roots.…”