| 花生壳磁性生物炭对颜料污泥厌氧消化及重金属形态的影响 |
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| 引用本文： | 阮仁俊,余成龙,李祎多,吴海芹,赵昌爽,黄斌,柯凡,操家顺.花生壳磁性生物炭对颜料污泥厌氧消化及重金属形态的影响[J].农业工程学报,2022,38(9):261-267. |
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| 作者姓名： | 阮仁俊 余成龙 李祎多 吴海芹 赵昌爽 黄斌 柯凡 操家顺 |
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| 作者单位： | 1. 安徽工程大学建筑工程学院，芜湖 241000;;3. 南京绘视界环保科技有限公司，南京 210018;;2. 河海大学环境学院，南京 210098; |
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| 基金项目： | 国家自然科学基金资助项目（51808001）；安徽省高等学校自然科学研究项目（KJ2020A0365）；安徽工程大学大学生创新创业训练计划项目（S202110363371）；大学生科研项目（2022DZ26） |
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| 摘 要： | 投加外源添加剂磁性生物炭（Magnetic Biochar，MBC）是解决颜料污泥厌氧消化效率低和重金属钝化效率低的有效途径。该研究选取农业废弃物花生壳制备生物炭（Biochar，BC），而BC对厌氧消化和重金属钝化的影响有限，对其赋磁改性制得MBC以提升影响效果。设置3组厌氧消化批式试验，A组为对照组，B组投加BC，C组投加MBC，探索花生壳MBC对颜料污泥厌氧消化效率及重金属Cr和Ni钝化的影响。结果表明，MBC投加可有效提升消化系统挥发性脂肪酸（Volatile Fatty Acids，VFAs）的产量，最高VFAs浓度达914.5 mg/L，较对照组（最高浓度603.9 mg/L）提升51.4%。同时MBC可实现生物炭和Fe3O4的双重直接种间电子传递（Direct Interspecies Electron Transfer，DIET）效应的耦合，缓解消化系统的酸化并提高有机物去除率和CH4累积产量。与对照组相比，挥发性固体（Volatile Solid，VS）去除率、累积甲烷产量、平均日甲烷产量和平均日甲烷产率分别提升37.8%、56.3%、56.3%和37.2%。此外，MBC投加可有效降低颜料污泥的重金属生物可利用态分配率和提升钝化效率，与原料相比，Cr的可交换态、可还原态质量占比降低43.6%、61.6%，而可氧化态、残渣态质量占比提升53.2%、243.6%；Ni的可交换态、可还原态质量占比降低41.0%、59.2%，而可氧化态、残渣态质量占比提升65.2%、181.4%。研究结果表明MBC可有效提高颜料污泥厌氧消化效率并降低重金属Cr和Ni的生物利用度，该研究有助于实现颜料污泥的稳定化、无害化、资源化利用。
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| 关 键 词： | 重金属 厌氧消化 颜料污泥 磁性生物炭 重金属生物利用度 钝化效率 |
| 收稿时间： | 2022/2/25 0:00:00 |
| 修稿时间： | 2022/4/28 0:00:00 |
Effects of peanut shell magnetic biochar on anaerobic digestion of pigment sludge and heavy metal speciation |
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| Ruan Renjun,Yu Chenglong,Li Yiduo,Wu Haiqin,Zhao Changshuang,Huang Bin,Ke Fan,Cao Jiashun.Effects of peanut shell magnetic biochar on anaerobic digestion of pigment sludge and heavy metal speciation[J].Transactions of the Chinese Society of Agricultural Engineering,2022,38(9):261-267. |
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| Authors: | Ruan Renjun Yu Chenglong Li Yiduo Wu Haiqin Zhao Changshuang Huang Bin Ke Fan Cao Jiashun |
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| Institution: | 1. School of Architecture and Civil Engineering, Anhui Polytechnic University, Wuhu 241000, China;;3. Nanjing Huishijie Environmental Protection Technology Co., Ltd, Nanjing 210018, China;; 2. College of Environment, Hohai University, Nanjing 210098, China; |
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| Abstract: | The addition of exogenous additive magnetic biochar (MBC) is an effective technology to solve the low efficiency of pigment sludge anaerobic digestion and the low efficiency of heavy metal passivation. To improve the anaerobic digestion efficiency of pigment sludge and stabilize the heavy metals, peanut shells, an agricultural waste product, were prepared as biochar (BC). BC had a limited effect on anaerobic digestion and heavy metal passivation, and then was magnetically modified to obtain magnetic biochar (MBC) to enhance impact effects. Group A was set as a control group. The prepared biochar (BC) and magnetic biochar (MBC) as exogenous additives were added in groups B and C, respectively. The effects of MBC on the anaerobic digestion efficiency of pigment sludge and the passivation of heavy metals Cr and Ni were investigated. The results showed that the MBC additive could effectively enhance the production of volatile fatty acids (VFAs) during anaerobic digestion. The maximum VFAs concentration of groups A, B and C reached 603.9, 642.5 and 914.5 mg/L, respectively. The maximum VFAs concentration of group C was enhanced by 51.4% compared with group A. In addition, the MBC additive was conductive to maintain the pH stability of the digestion system and provided favorable environmental conditions to enhance the anaerobic digestion efficiency. The VS removal rate and cumulative methane production were 45.5%, 48.3%, 62.7% and 10.01, 10.63, 15.65 L in groups A, B and C, respectively. As such, average daily methane production and average daily methane yield obtained 333.6, 354.2, 521.6 mL and 116.5, 121.6, 159.8 mL/g in groups A, B and C. Clearly, the optimal anaerobic digestion efficiency was achieved in group C and the worst in group A. It benefits from both biochar and Fe3O4 contributing to the Direct Interspecies Electron Transfer (DIET) among microorganisms. MBC can facilitate the coupling of dual direct interspecies electron transfer effect of biochar and Fe3O4. The efficiency of electron transfers from the donor to the acceptor of the anaerobic digestion system was significantly enhanced, thus increasing the rate of organic matter consumption and methane production. The heavy metals (Cr and Ni) contained in pigment sludge can also cause significant secondary contamination besides biorefractory organics. Although the total concentration of heavy metals can be a useful indicator of digested sludge pollution, the potential toxicity of heavy metals is linked to their bioavailability and chemical speciation. The chemical speciation of heavy metals in pigment sludge consist of four types, namely exchangeable, reducible, oxidizable and residual speciation. The exchangeable speciation is the most bioavailable, the reducible speciation is the next most bioavailable, while the oxidizable and residual speciation exist in complexes and can be stable in the natural environment or in the sludge for a long time. The findings suggest that MBC additives significantly affected the chemical speciation of heavy metals Cr and Ni, which contributed to reducing the bioavailability of heavy metals (BHM) in digested pigment sludge. Compared with the feedstock, the mass percentages of exchangeable speciation Cr decreased by 7.8%, 13.0% and 43.6% in groups A, B and C, respectively. As for reducible speciation Cr, reduced by 8.9%, 35.0%, 61.6%. While the mass percent concentration of exchangeable speciation Ni got a 7.1%, 18.5% and 41.0% reduction in groups A, B and C, respectively. As for reducible speciation Ni, got 9.9%, 22.3% and 59.2%. In groups A, B and C, the passivation efficiency of Cr and Ni achieved 8.2%, 20.9%, 50.1% and 8.4%, 18.5%, 48.9%, respectively. The above results indicate that MBC could effectively improve the anaerobic digestion efficiency of pigment sludge and decrease the bioavailability of heavy metals (Cr and Ni). It contributes to the stabilization, innocuity treatment and resource utilization of pigment sludge. |
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| Keywords: | heavy metals anaerobic digestion pigment sludge magnetic biochar bioavailability of heavy metals passivation efficiency |
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