Science of the Total Environment ( IF 9.8 ) Pub Date : 2021-05-11 , DOI: 10.1016/j.scitotenv.2021.147683 Gahyun Baek , Ruggero Rossi , Pascal E. Saikaly , Bruce E. Logan
The addition of electrically conductive materials may enhance anaerobic digestion (AD) efficiency by promoting direct interspecies electron transfer (DIET) between electroactive microorganisms, but an equivalent enhancement can also be achieved using non-conductive materials. Four high surface area brush materials were added to AD reactors: non-conductive horsehair (HB) and polyester (PB), and conductive carbon fiber (CB) and stainless steel (SB) brushes. Reactors with the polyester material showed lower methane production (68 ± 5 mL/g CODfed) than the other non-conductive material (horsehair) and the conductive (graphite or stainless steel) materials (83 ± 3 mL/g CODfed) (p < 0.05). This difference was due in part to the higher biomass concentrations using horsehair or carbon (135 ± 43 mg) than polyester or stainless steel or materials (26 ± 1 mg). A microbial community analysis indicated that the relative abundance of electroactive microorganisms was not directly related to enhanced AD performance. These results show that non-conductive materials such as horsehair can produce the same AD enhancement as conductive materials (carbon or stainless steel). However, if the material, such as polyester, does not have good biomass retention, it will not enhance methane production. Thus, electrical conductivity alone was not responsible for enhancing AD performance. Polyester, which has been frequently used as a non-conductive control material in DIET studies, should not be used for this purpose due to its poor biocompatibility as shown by low biomass retention in AD tests.
中文翻译:
不同类型的具有不同电导率和生物相容性的高表面积刷式纤维对厌氧消化中甲烷生成速率的影响
导电材料的添加可以通过促进电活性微生物之间的直接种间电子转移(DIET)来提高厌氧消化(AD)的效率,但是使用非导电材料也可以实现等效的增强。将四种高表面积的刷子材料添加到AD反应器中:非导电马毛(HB)和聚酯(PB),以及导电碳纤维(CB)和不锈钢(SB)刷子。使用聚酯材料的反应器显示出的甲烷生成量(68±5 mL / g COD进料)低于其他非导电材料(马毛)和导电(石墨或不锈钢)材料(83±3 mL / g COD进料)(p<0.05)。这种差异部分是由于使用马毛或碳(135±43 mg)比使用聚酯或不锈钢或材料(26±1 mg)更高的生物质浓度造成的。微生物群落分析表明,电活性微生物的相对丰度与提高的AD性能没有直接关系。这些结果表明,非导电材料(例如马毛)可以产生与导电材料(碳或不锈钢)相同的AD增强作用。但是,如果该材料(例如聚酯)不具有良好的生物质保留能力,则不会提高甲烷的产生。因此,仅电导率不负责增强AD性能。聚酯,在DIET研究中经常被用作非导电性控制材料,