| 摘要: |
| 【目的】研究生物炭和纳米零价铁(nano zero-valent iron, nZVI) 2种吸附剂对鸡粪中温厌氧发酵产气特性的影响，以寻求适宜的吸附剂及其添加量。【方法】采用中温(35±1) ℃恒温批次试验，以鸡粪为发酵原料，分别添加不同质量分数(0%(对照),2.5%,5%,7.5%和10%)的生物炭和不同质量分数(0%（对照）,0.25%,0.5%,0.75%和1%)的nZVI，探索添加生物炭和nZVI对鸡粪厌氧发酵产气特性动态的影响。【结果】添加生物炭后，鸡粪厌氧发酵累积沼气产量随着时间的延长总体不断增加；试验结束时，添加生物炭各处理的累积沼气产量显著高于对照(P<0.05)，其中添加5%生物炭处理的累积沼气产量最高，达到21 532 mL。添加nZVI后，累积沼气产量随时间的延长呈增加趋势；试验结束时，未添加nZVI的累积沼气产量最高，达到11 101 mL。随着生物炭添加量的增加，平均沼气产量呈单峰变化趋势，其中添加5%生物炭处理的平均沼气产量最高，达到414 mL/d；随着nZVI添加量的增加，平均沼气产量呈先降后增再降的变化趋势。与对照相比，添加生物炭均能显著提高甲烷含量，而添加nZVI的各处理仅1% nZVI才能显著提高甲烷含量。随着发酵时间的增加，添加生物炭后pH总体呈上升-下降-上升趋势，添加nZVI后pH总体呈逐渐上升趋势。添加生物炭和nZVI的各处理后发酵过程中挥发性脂肪酸质量浓度均呈上升-下降-上升-下降的变化趋势，氨态氮质量浓度发酵初期快速增加，之后总体呈降低的趋势。与对照相比，添加生物炭处理的总固体和挥发性固体的产气效率均显著增加(P<0.05)，其中添加5%生物炭的处理总固体和挥发性固体产沼气效率最高；而添加nZVI的总固体和挥发性固体产气效率均降低。【结论】添加生物炭对鸡粪厌氧发酵有促进作用，在以250 g干鸡粪为发酵原料、发酵总体积700 mL、发酵温度(35±1) ℃的条件下，当生物炭添加量为15.32 g时，累积沼气产量最高为21 844.75 mL；添加nZVI对鸡粪厌氧发酵产沼气无促进作用。 |
| 关键词: 生物炭 纳米零价铁 鸡粪 厌氧发酵 发酵特性 |
| DOI： |
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| 基金项目:国家自然科学基金项目(51508467,41871205）；中国博士后基金项目(2016T90950,2015M582708）；陕西省循环农业工程技术研究中心项目(2019HBGC-13） |
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| Effects of two types of adsorptive additives on biogas production characteristics of chicken manure in anaerobic fermentation |
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ZENG Ruiyuan,RAN Xueling,WANG Yanbo,et al
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| Abstract: |
| 【Objective】The effects of biochar and nZVI on gas production characteristics of chicken manure in medium temperature anaerobic fermentation were studied to obtain appropriate adsorbent and its addition amount.【Method】Chicken manure was used as raw material for batch fermentation at medium temperature (35±1) ℃ with addition of biochar (0%(contrast),2.5%,5%,7.5% and 10%) and nZVI (0% (contrast),0.25%,0.5%,0.75% and 1%).Then,the effects on gas production characteristics of the anaerobic fermentation of chicken manure were analyzed.【Result】With biochar addition,cumulative biogas production of chicken manure anaerobic fermentation increased with time.At the end of experiment,cumulative biogas production and methane content of chicken manure were significantly higher than the control (P<0.05).The optimal amount of biochar was 5%.Under this condition,cumulative biogas output was 21 532 mL.With nZVI addition,cumulative biogas yield increased with time as well.Cumulative biogas yield with 0% nZVI was the highest of 11 101 mL at the end of experiment.With the increase of biochar addition,average biogas production showed a unimodal trend.The highest average biogas production was 414 mL/d with 5% biochar.With the increase of nZVI amount,average biogas production decreased first followed by increase and subsequent decrease.Compared with the control,biochar addition can significantly increase methane content,while only 1% nZVI can significantly increase methane content.With the increase of fermentation time,pH showed increase decrease increase trend with biochar addition,while it increased gradually with nZVI addition.Mass concentration of volatile fatty acids in fermentation process showed a trend of increase decrease increase decrease.Concentration of ammonia nitrogen increased rapidly at the beginning of fermentation,followed by a general decreasing trend.Compared with the control,total solid mass and gas production efficiency of volatile solids treated with biochar were significantly increased (P<0.05) with the highest in 5% biochar treatment.Gas production efficiency of total solids and volatile solids reduced with nZVI addition.【Conclusion】Biochar addition can promote anaerobic fermentation of chicken manure.The maximum cumulative biogas output of 21 844.75 mL was obtained with dry chicken manure 250 g,total fermentation volume 700 mL,fermentation temperature (35±1) ℃,and biochar addition 15.32 g.Adding nZVI had no effect on anaerobic fermentation of chicken manure. |
| Key words: biochar nano zero-valent iron(nZVI) chicken manure anaerobic fermentations fermentation characteristics |
