Exploring the Influence of Biochar-Supported Nano-Iron Oxide on Phosphorus Speciation Transformation and Bacterial Community Structure in Aerobic Pig Manure Composting Processes
Existing studies have demonstrated the positive effects of nano-sized iron oxide on compost maturity, yet the impact of nano-sized iron oxide on phosphorus speciation and bacterial communities during the composting process remains unclear. In this study, pig manure and straw were used as raw materia...
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| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2024-12-01
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| Series: | Microorganisms |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2076-2607/12/12/2593 |
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| Summary: | Existing studies have demonstrated the positive effects of nano-sized iron oxide on compost maturity, yet the impact of nano-sized iron oxide on phosphorus speciation and bacterial communities during the composting process remains unclear. In this study, pig manure and straw were used as raw materials, with biochar-supported nano-sized iron oxide (BC-Fe<sub>3</sub>O<sub>4</sub>NPs) as an additive and calcium peroxide (CaO<sub>2</sub>) as a co-agent, to conduct an aerobic composting experiment with pig manure. Four treatments were tested: CK (control), F1 (1% BC-Fe<sub>3</sub>O<sub>4</sub>NPs), F2 (5% BC-Fe<sub>3</sub>O<sub>4</sub>NPs), and F3 (5% BC-Fe<sub>3</sub>O<sub>4</sub>NPs + 5% CaO<sub>2</sub>). Key findings include the following. (1) BC-Fe<sub>3</sub>O<sub>4</sub>NPs increased compost temperatures, with F3 reaching 61℃; F1 showed optimal maturity (C/N ratio: 12.90). (2) BC-Fe<sub>3</sub>O<sub>4</sub>NPs promoted stable phosphorus forms; Residual-P proportions were higher in F1, F2, and F3 (25.81%, 51.16%, 51.68%) than CK (19.32%). (3) Bacterial phyla <i>Firmicutes</i>, <i>Actinobacteria,</i> and <i>Proteobacteria</i> dominated. BC-Fe<sub>3</sub>O<sub>4</sub>NPs altered community composition, especially on day 7. <i>Firmicutes</i> dominated CK, F1, and F3; <i>Proteobacteria</i> dominated F2. At the genus level, day 7 showed <i>Corynebacterium</i> (CK), <i>Clostridum</i> (F1, F3), and <i>Caldibacillus</i> (F2) as predominant. (4) Pearson correlation analysis revealed shifted correlations between phosphorus forms and bacterial phyla after BC-Fe<sub>3</sub>O<sub>4</sub>NPs addition. <i>Firmicutes</i> positively correlated with NaOH-OP in F1 during the thermophilic phase, facilitating phosphate release and adsorption by BC-Fe<sub>3</sub>O<sub>4</sub>NPs. The significance of correlations diminished with increasing additive concentration; in F3, all phyla positively correlated with various phosphorus forms. |
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| ISSN: | 2076-2607 |