不同麦秆生物炭强化餐厨垃圾厌氧消化

Anaerobic digestion of food waste enhanced by different wheat straw biochars

为明确生物炭制备条件对生物炭性质及厌氧消化效果的影响,本研究以小麦秸秆(WS)为原料,在不同热解温度和不同KOH改性浓度条件下制备出不同类型的麦秆生物炭(WBC).研究发现,较低的热解温度能够保护WBC表面的官能团,而较高的热解温度则能够提高WBC的比表面积,孔容及平均孔径.KOH改性能够向WBC表面引入─OH,且一定程度上会影响WBC的比表面积,孔容及平均孔径.将制得的WBC分别添加到餐厨垃圾厌氧消化(KWAD)系统中,发现所有WBC均能够提高KWAD的总产气量.其中WS650与WS450-2的促进作用最显著,较CK分别提高了32.82%和30.01%的总产气量.在关键酶活性的研究中,发现WS450-2的辅酶F420与脱氢酶活性大大提升,这可能与其表面丰富的官能团有关.在微生物群落结构的研究中,WS450-2在富集厚壁菌门(Firmicutes),抑制非相关细菌方面展现了较大优势;WS650在富集甲烷八叠球菌属(Methanosarcina),抑制非相关古菌方面展现了较大优势.最后通过冗余分析明确了WBC制备工艺和表征指标与KWAD产气动力学参数,过程参数,酶活性和微生物丰度之间的相关关系.发现KOH改性WBC能够通过调节挥发性脂肪酸与pH值影响沼气产量,其较大的孔容和比表面积能够更好地富集厚壁菌门(Firmicutes);高温热解WBC则能够更好地富集甲烷八叠球菌属(Methanosarcina).

In this study,different types of wheat straw biochars(WBC)were prepared from wheat straw(WS)at different pyrolysis temperatures and KOH modified concentrations to clarify the effects of biochar preparation conditions on its properties and anaerobic digestion.It was observed that a lower pyrolysis temperature could protect the functional groups on the surface of WBC,while a higher pyrolysis temperature could increase the specific surface area,pore volume,and average pore size of WBC.KOH modification can introduce-OH to the surface of WBC and affect the specific surface area,pore volume,and average pore size of WBC to some extent.The WBCs were added to the kitchen waste anaerobic digestion(KWAD)system,and all WBCs were found to increase the total biogas production of KWAD,of which both WS650 and WS450-2 had the most significant promotion effect,increasing the total biogas production by 32.82%and 30.01%,respectively,compared with CK.In view of key enzyme activities,the coenzyme F420 and dehydrogenase activities of WS450-2 were found to be greatly enhanced,which may be related to the abundance of its functional groups on the surface.And the WS450-2 showed a greater advantage in enriching Firmicutes and suppressing unrelated bacteria,while WS650 in enriching Methanosarcina and suppressing unrelated archaea.Finally,there was the correlation of both the preparation process and characterization indexes of WBC with the KWAD biogas production kinetic parameters,process parameters,enzyme activity,and microbial abundance.That the KOH modified WBC could affect biogas production by adjusting volatile fatty acids and pH;and its larger pore volume and specific surface area could better enrich Firmicutes,while the high-temperature pyrolysis of WBC could better enrich Methanosarcina.