Liang Yue-Gan, Li Xiu-Juan, Zhang Jin, Zhang Li-Gan, Cheng Beijiu
School of Resource and Environment, Anhui Agricultural University, Hefei, 230036, People's Republic of China.
Key Laboratory of Biomass Improvement and Conversion of Anhui Province, School of Life Sciences, Anhui Agricultural University, Hefei, 230036, People's Republic of China.
Environ Sci Pollut Res Int. 2017 May;24(13):12328-12337. doi: 10.1007/s11356-017-8832-9. Epub 2017 Mar 29.
Low methane production and high levels of heavy metal in pig slurries limit the feasibility of anaerobic digestion of pig manure. In this study, changes in the methane production and bioavailability of heavy metals in the anaerobic digestion of diluted pig manure were evaluated using single and combined action of microscale zero-valence iron (ZVI) and magnetite. After 30 days of anaerobic digestion, the methane yield ranged from 246.9 to 334.5 mL/g VS added, which increased by 20-26% in the group added with microscale ZVI and/or magnetite relative to that in the control group. Results of the first-order kinetic model revealed that addition of microscale ZVI and/or magnetite increased the biogas production potential, rather than the biogas production rate constant. These treatments also changed the distribution of chemical fractions for heavy metal. The addition of ZVI decreased the bioavailability of Cu and Zn in the solid digested residues. Moreover, a better performance was observed in the combined action of microscale ZVI and magnetite, and the ZVI anaerobic corrosion end-product, magnetite, might help enhance methane production through direct interspecies electron transfer in ZVI-anaerobic digestion process.
猪粪浆中低水平的甲烷产生量和高含量的重金属限制了猪粪厌氧消化的可行性。在本研究中，使用微尺度零价铁（ZVI）和磁铁矿的单一及联合作用，评估了稀释猪粪厌氧消化过程中甲烷产生量和重金属生物有效性的变化。厌氧消化30天后，甲烷产量在246.9至334.5 mL/g添加挥发性固体之间，相对于对照组，添加微尺度ZVI和/或磁铁矿的组增加了20 - 26%。一级动力学模型结果表明，添加微尺度ZVI和/或磁铁矿提高了沼气生产潜力，而非沼气生产速率常数。这些处理还改变了重金属的化学形态分布。添加ZVI降低了消化后固体残渣中铜和锌的生物有效性。此外，微尺度ZVI和磁铁矿的联合作用表现更佳，并且ZVI厌氧腐蚀终产物磁铁矿可能通过ZVI - 厌氧消化过程中的种间直接电子传递有助于提高甲烷产量。
