运行微生物燃料电池减排稻田土壤甲烷的研究

Application of Microbial Fuel Cells in Reducing Methane Emission from Rice Paddy

为了研究稻秆还田条件下运行微生物燃料电池(microbial fuel cells,MFCs)是否能有效减排稻田甲烷,本研究将添加质量分数0.5%稻秆的土壤装入MFCs反应器,淹水并种植水稻后运行MFCs.待水稻经历苗期、分蘗期、晒田期、灌浆期和成熟期共98 d后,停止MFCs运行.在MFCs运行过程中实时连续记录电压,每周一次采用静态箱法搜集并检测反应器的甲烷排放通量.结果表明,MFCs电流在分蘗期逐步升高并达到峰值,并且运行MFCs显著降低添加稻秆土壤在苗期和分蘗期的甲烷累积排放通量.原因可能与产电菌和产甲烷菌竞争有机底物有关.MFCs运行98 d后,水稻株高、地上和地下部分生物量,以及产量未受显著影响.本研究为稻田CH_4减排提供了一种潜在的绿色可持续的技术.

We aimed to study whether the methane emission from rice paddy with straw return can be alleviated in microbial fuel cells（MFCs）.In our study,the soil mixed with 0.5%（mass fraction） rice straw was packed into MFCs reactors,then flooded with excess of sterilized water and transplanted with rice seedlings followed by the operation of MFCs.The MFCs were operated for 98 days covering five stages of seeding,tillering,mid-season aeration,rice filling,and ripening.The voltage data were recorded continuously and in real time during the MFCs operation and the methane emitted was collected once a week using the static chamber method and the methane emission flux was determined by gas chromatography.The results showed that the MFCs current increased and reached the peak value in the seeding and tillering stages and the operation of MFCs significantly reduced the accumulative methane emission in these two stages.The possible reason could be that the electrogens competed with methanogens for organic substrates.The height,the above and below ground biomass,and the productivity of rice plants were not significantly affected by the 98-day operation of MFCs.Our study provides a potential green and sustainable technology for the reduction of CH4 emission from rice paddy fields.