Tong Zhenye, Zhang Haorong, Li Siqin, Ma Liqian, Li Zhenguo, Yong Xiaoyu, Liu Fenwu, Zhou Jun
Bioenergy Research Institute, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, Jiangsu 211816, China.
Bioenergy Research Institute, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, Jiangsu 211816, China; Environmental Engineering Laboratory, College of Resource and Environment, Shanxi Agricultural University, Taigu 030801, China.
Water Res. 2025 Sep 1;283:123763. doi: 10.1016/j.watres.2025.123763. Epub 2025 May 1.
High levels of antibiotics and antibiotic resistance genes (ARGs) still exist in biogas slurry after anaerobic digestion of cow manure. In this study, direct bio-drying strategies of cow manure biogas slurry without solid-liquid separation for the removal of antibiotics and ARGs were explored. The results showed that, after direct bio-drying of biogas slurry, the moisture contents decreased to 25.2 %-31.5 %. The maximum temperatures of the piles reached 76.1-77.4 °C, which is close to ultra-high temperatures (>80 °C). Direct biogas slurry bio-drying (CK treatment) achieved efficient removal of antibiotics, ARGs, and mobile genetic elements (MGEs) (95.4 %, 98.6 % and 86.7 % removal, respectively). Compared to the CK treatment, molecular membrane covering (MMC) alone was the most effective in further significantly decreasing the antibiotic concentration and the abundance of ARGs and MGEs in the final bio-dried samples, followed by food waste hydrochar (FHC) addition alone. Methanogenic archaea were identified as potential hosts for ARGs based on Network analysis. FHC addition-MMC increased the abundance of potential hosts for ARGs and promoted the expression of microbial methane metabolism function relative to the CK treatment during the later stages of bio-drying, thereby decreasing the removal efficiency of ARGs. The results of structural equation model and redundancy analysis showed that MGEs had the most significant direct effect on ARGs and moisture content had the highest relative contribution to changes in ARGs. In summary, direct bio-drying strategies were able to efficiently remove antibiotics and ARGs from cow manure biogas slurry and also achieve biological dewatering of the biogas slurry.
牛粪厌氧消化后的沼液中仍存在高浓度的抗生素和抗生素抗性基因（ARGs）。本研究探索了牛粪沼液不进行固液分离直接生物干燥去除抗生素和ARGs的策略。结果表明，沼液直接生物干燥后，水分含量降至25.2%-31.5%。堆体最高温度达到76.1-77.4℃，接近超高温（>80℃）。沼液直接生物干燥（CK处理）实现了抗生素、ARGs和可移动遗传元件（MGEs）的高效去除（去除率分别为95.4%、98.6%和86.7%）。与CK处理相比，单独覆盖分子膜（MMC）对进一步显著降低最终生物干燥样品中的抗生素浓度以及ARGs和MGEs丰度最为有效，其次是单独添加餐厨垃圾生物炭（FHC）。基于网络分析，产甲烷古菌被确定为ARGs的潜在宿主。在生物干燥后期，相对于CK处理，添加FHC-MMC增加了ARGs潜在宿主的丰度，并促进了微生物甲烷代谢功能的表达，从而降低了ARGs的去除效率。结构方程模型和冗余分析结果表明，MGEs对ARGs的直接影响最为显著，水分含量对ARGs变化的相对贡献最高。综上所述，直接生物干燥策略能够有效去除牛粪沼液中的抗生素和ARGs，同时实现沼液的生物脱水。
