Phosphorus transformation and bioavailability in livestock manure through aerobic composting and anaerobic digestion

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Vol. 505; p. 159285
• Main Authors: Ran, Xueling, Li, Shunjin, Tejaswi Uppuluri, Naga Sai, Deng, Yun, Su, Ya, Huang, Guangqun, Dong, Renjie, Müller, Joachim, Wei, Quanyuan, Guo, Jianbin, Oechsner, Hans
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.02.2025
• Subjects: 31P NMR; Aerobic Composting; Anaerobic digestion; Enzymatic hydrolysis; P organic fertilizer; Enzymatic hydrolysis; Anaerobic digestion; Aerobic Composting; 31P NMR; P organic fertilizer
• ISSN: 1385-8947
• DOI: 10.1016/j.cej.2025.159285

[Display omitted] •Comprehensive analysis the forms and contents of P after AC and AD.•Changes in bioavailable P during different biological treatment technologies were evaluated.•Comparison of the bioavailable P in organic fertilizers produced by AC and AD.•Elucidate the correlation between the measured P in different methods and Olsen-P.•It is suggested that livestock manure with high phytate content be treated by AD. Phosphorus (P) forms and distribution in the organic waste subject to treatment is crucial for the efficient nutrient recycling and sustainable fertilizer production. This study investigated the transformations of inorganic and organic P forms, as well as bioavailable P, after aerobic composting (AC) and anaerobic digestion (AD) processes of cattle manure by a novel combination method of chemical sequential extraction method, enzymatic hydrolysis, nuclear magnetic resonance (NMR) and X-ray diffraction (XRD). The results revealed that AC and AD processes differentially impacted P forms and bioavailability. Labile P (H2O-P＆NaHCO3-P) was reduced by 11.21 % after 25 day-AD, stimulating the accumulation of Ca-P (non-labile P), however, 18.15 % of labile P increased after AC. Both AC and AD did not affect the dominance of orthophosphate (70.92 %-84.75 %% of total P). Phytate-like P with poor plant availability, was degraded by 48.26 % after AD but only 18.03 % after AC. In terms of overall fertilizer bioavailability, AC increased Olsen-P by 22.3 %, while AD decreased Olsen-P by 14.9 %. Structural equation modeling (SEM) further supported these findings, indicating AC increased Olsen-P by promoting the conversion of HCl-P to more labile forms and facilitating the transformation of soluble organic P to inorganic P, while AD decreased Olsen-P due to the conversion of soluble inorganic P to less readily available forms, such as HCl-P and NaOH-P. This research hints that AC-derived fertilizers are a source of readily available P, while AD is more appropriate for treating organic waste with high phytate content, and producing slow-release P fertilizer.