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Phosphorus (P) in societal waste streams can be recycled and used as recycled P fertilisers (RPFs). When developing new technologies for P recycling, life cycle assessment (LCA) can be used to assess their environmental impact and support environmentally friendly decisions. In LCA calculations, inventory factors describe, for example, the emissions, resource requirements and potential substitution of products. The Phosphorus Life Cycle Inventory (PLCI) model is a tool for estimating such inventory factors for the use of RPFs. The main objective of this study was to develop the PLCI model from its previous parameterisation for Denmark to make it applicable to all countries and regions of the EU. This was undertaken by considering parameters that describe regional conditions affecting the loss of P, crop P uptake and potential mineral fertiliser substitution. Such parameters include soil type, soil P status, soil erosion, groundwater leaching, crop types, productivity and crop P concentrations. Several RPFs were incorporated into the model, including coefficients describing the partitioning to the labile, plant-available P fraction. To illustrate the applicability of the model, a case study was performed. Applications of RPFs were modelled in the Copenhagen region in Denmark and the Piedmont region in Italy. The higher soil erosion rate in Piedmont resulted in over six times greater P loss than in Copenhagen. The difference in P fertilisation practice between the regions had a strong impact on the mineral fertiliser substitutions. The results point to the importance of defining the fertilisation regime of the region being modelled, and this is now possible with the new, more dynamic version of PLCI. In conclusion, the new PLCI 2.0 model provides a dynamic tool for LCA practitioners to estimate region-specific inventory factors for RPFs. The model is relatively easy to use and captures differences between fertilisers with varying P availability and between applications in different regions of the EU. [Display omitted] • A life cycle inventory model for recycled P fertilisers was developed. • Regionalisation allowed differentiation in fertilisation effects between regions. • The model was applied to case studies in Denmark and Italy. • Higher soil erosion in Piedmont caused six times higher P loss than in Copenhagen. • The model captured differences between fertilisers with varying P availability. [ABSTRACT FROM AUTHOR]

Boron (B) fertilizers are essential for global crop production. Sustainable B use demands a higher efficiency of B fertilizers through controlled B release and an enhanced B recycling from secondary sources, e.g. B-impregnated cellulose fiber insulation (CFI) waste. In this study, thermochemical treatments based on combustion and pyrolysis were investigated for processing CFI waste into a slow-release B fertilizer. Hot-water extractions of obtained materials confirmed that slow-release properties were achieved, and material characterization with XRD, FTIR and 11B-NMR showed that these were largely the result of formation of sparingly soluble Ca–B phases. A seedling toxicity test with fodder rape demonstrated the benefit of this slow-release B in comparison with conventional soluble B to circumvent toxicity, suggesting potential for B application via seed coatings. Finally, a fertilization trial with fodder rape and poppy seed showed that most slow-release B compounds were equally effective as soluble B at recommended B doses, while slow-release B can still benefit from reduced B leaching losses. [Display omitted] • Thermochemical processing of B-rich cellulose fiber insulation (CFI) was tested. • Obtained combustion and pyrolysis products had slow-release B characteristics. • Slow-release B was largely the result of formation of sparingly-soluble Ca–B phases. • B toxicity to plants could be avoided using treated CFI instead of soluble B. • In a plant fertilization trial, treated CFI was equally effective as soluble B. [ABSTRACT FROM AUTHOR]

Cycling of nutrients, such as phosphorus (P) and nitrogen (N), is essential for all life: Nutrients are crucial for securing societies' food systems and valuable raw materials for industrial processes. Recycling nutrients from various side and waste streams instead of virgin nutrients has attracted considerable interest in the society, particularly as geopolitical and epidemic issues have caused many nations to reconsider how they ensure flows of critical resources by increasing the Circular Economy (CE) principles. This study examines what drivers and barriers catalyze nutrient circulation in national settings, requiring diverse actors to support intentional nutrient recycling. By taking multidisciplinary and ecosystem approaches, we examine diverse sociotechnical drivers and barriers and the actor ecosystem involved. We conduct an extensive qualitative case study on nutrient circulation (P and N) in a Finnish context, analyzing over 150 documents and interviewing over 20 diverse actors (from diverse companies through ministries to farmers) involved in nutrient recycling, from biowaste through agricultural biomasses and sludge from municipal wastewater treatment plants. Our study 1) generates an ecosystem actor map uncovering diverse actors enabling nutrient recycling in society; and 2) exposes technological, business, organizational, regulatory, linguistic, visual, and psychological drivers and barriers shaping nutrient circulation. It explains the sociotechnical preconditions for different actor/stakeholder groups to adopt and advocate circular economy (CE) principles for nutrient recycling, which are generalizable to other critical resources. The study contributes to CE research and advises practitioners by providing a comprehensive catalyst toolbox to advance nutrient circulation and facilitate its acceptability and diffusion. [Display omitted] • Qualitative study analyzes drivers/barriers for recycling of critical resources, nutrients. • "Ecosystem" is applied as a metaphor for a multi-actor constellation enabling recycling. • Key actors for nutrient recycling ecosystem vary from farmers and businesses to policymakers. • Catalysts are technical, business, organizational, regulatory, linguistic, visual, and psychological. • A framework is developed for sociotechnical drivers advancing circular economy diffusion. [ABSTRACT FROM AUTHOR]

In a context of climate change and circular economy, it is fundamental to produce animal manure-based fertilizers attractive to farmers who are reluctant to use heterogeneous materials, poorly characterized and with unbalanced nutrient contents, namely N:P ratios different from plant requirements. Hence, the aim of the present study was to assess the potential of different treated and non-treated animal manures to produce tailor-made manure-based fertilizers with known N:P ratios. Seven manures were considered: cattle, caprine and poultry solid manures, two contrasting cattle slurries and two contrasting swine slurries. Slurries were further treated by solid-liquid separation, acidification, and acidification followed by solid-liquid separation. Raw and treated manures were fully characterized to assess the effect of manure type and treatment on their nutrient contents and N:P ratios, to incorporate them in manure-based fertilizers with selected N:P ratio. The present results were essential to support the manure-based fertilizer production and identify which materials could be considered: it appears clearly that the pig slurry with all stages of production and the correspondent liquid fraction cannot be used due to their low nutrients content. It was shown that the solid fractions rich in P and with a N T :N–NH 4 + ratio close to 1 are an excellent material to prepare manure-based fertilizers. Acidification, combined with solid-liquid separation, produced a liquid fraction rich in both N and P and with a N T :P T ratio close to 1, with the additional benefit of a slow N-release material. Some of the manures or sub-products obtained after treatment provided the usual N:P ratio required by farmers and could be used directly as substitutes of mineral fertilizers. Nevertheless, the blending of some of these materials has a stronger potential to the production of specific manure-based fertilizer. • Animal species and manure management influence manure composition and N:P ratio. • Slurry treatment is a good tool to modify N:P ratio of manure. • Combination of raw and/or treated manures allow producing manure based fertilizers. • Manure based fertilizers can have N:P ratio similar to mineral fertilizers.. [ABSTRACT FROM AUTHOR]

A liquid digestate rich in ammonium nitrogen (8.3 g L−1) was collected from an agricultural biogas plant and supplied to microalgae cultures as their only nitrogen source. Chlorella vulgaris was cultivated for up to 21 days, both under controlled conditions in laboratory-scale glass-column photobioreactors as well as outdoors in an open pilot-scale thin-layer photobioreactor. By systematically addressing issues associated with the use of liquid digestate (i.e., turbidity, nutrient imbalance, ammonium toxicity, and acidification), microalgae were robustly cultivated at a high density and cultures achieved a net biomass dry weight of between 10 and 14 g L−1, and a productivity of up to 0.93 g L−1 d−1 (93% of maximum expectation). Cultivation in the thin-layer photobioreactor achieved areal productivities between 7 and 10 g m−2 d−1. Water acidification due to the uptake of ammonium by microalgae was prevented by a controlled addition of NaOH. A detailed mass balance showed that, despite high removal efficiencies (approximately 3% of the supplied nitrogen remained in the medium), microalgae assimilated only 40–60% of the supplied nitrogen and, consequently, a large amount of nitrogen was lost to the atmosphere. [Display omitted] • Liquid digestate was used as nitrogen source to cultivate microalgae. • Chlorella vulgaris was cultivated successfully at laboratory and pilot scales. • Algal biomass reached net dry weights of up to 13.7 g L−1. • Acidification of the growth medium and ammonium toxicity were controlled. • 40–60% of the nitrogen was lost to the atmosphere during the cultivation. [ABSTRACT FROM AUTHOR]

The study developed a holistic approach based on the thermal digestion (TD) technique for the rapid conversion of solid organic waste (SOW) into nutrient-rich organic fertilizer. The effect of digestion temperatures (110oC–170 °C) on the weight reduction from the SOW and the availability of the nutrients were thoroughly investigated. The potential weight reduction of 75.2% was achieved at a temperature of 150 °C for 135 min, as illustrated by response surface methodology (RSM). Scanning electron microscope (SEM) study was carried out to analyze the changes into surface morphology of the sample before and after the digestion. Fourier transform infrared (FTIR) analysis was conducted to study the mineralization process. Thermogravimetric-Differential thermal analysis (TG-DTA) was conducted to study the thermal decomposition behavior of the untreated and digested SOW. The digested SOW resulted high nutrient-rich end product (N-2.08 ± 0.01%, P-0.42 ± 0.00%, & K-1.65 ± 0.06%), which have potential to be used as organic fertilizer. Fertilizing potential of the digested SOW complied with the delineated norms of the organic fertilizer given by the Fertilizer Association of India (2019). Maturity and phytotoxicity of the digested SOW were explored on the basis of C:N ratio (18.07 ± 0.17), humification index (3.43 ± 0.02), heavy metals content, as well as through seed germination index (>90%). The proposed technology may lead to the paradigm shift in waste management and provides an efficient alternative for the recycling of nutrients. [Display omitted] • A cleaner technology for sustainable management of solid organic waste. • Rapid conversion of solid organic waste into nutrient rich organic fertilizer. • 150 °C was found to be the most optimum temperature for thermal digestion. • Phytotoxin free organic fertilizer suitable for agricultural sustainability. [ABSTRACT FROM AUTHOR]