抗生素菌渣是原料药生产企业主要的危险废物，年产量150万吨-200万吨。抗生素菌渣中高浓度的抗生素和耐药基因可能造成处理过程中耐药性的传播。抗生素菌渣含水率高、有机物含量高、碳氮比低，单一处理技术难以满足抗生素菌渣处理的要求。本研究以链霉素菌渣和青霉素菌渣为主要研究对象，构建了水热预处理-深度脱水-滤液厌氧消化-滤饼热解的工艺路线，从基因耐药和表型耐药两个方面评价了处理过程的耐药性变化，对处理体系开展了技术经济分析。 水热预处理提高了抗生素菌渣的脱水性能和生物降解性能，180 ?C水热预处理后抗生素菌渣中颗粒粒径降低到20 μm-30 μm，80%以上的结合水转化为自由水，40%以上悬浮性固体转化为溶解性固体，抗生素菌渣产甲烷潜能提高了5倍。5大类10种抗生素菌渣在180 ?C和30分钟水热预处理后实现了深度脱水和残留抗生素的灭活。抗生素菌渣水热滤液在上流式厌氧污泥床耦合侧流化学脱氮工艺中，70%-75%的有机物以沼气的形式回收，70%-88%的氨氮被脱除。热解可以回收水热滤饼中80%以上的有机物，热解温度高于600 ?C生产的抗生素菌渣热解炭符合Ⅲ级生物炭标准。 140 ?C水热温度可以将抗生素菌渣中链霉素和青霉素含量降至1 μg/g以下。180 ?C水热预处理后，抗生素菌渣中耐药基因和可移动遗传元件下降了2.4 logs-7.4 logs，热解温度高于400 ?C可以破坏水热滤饼中全部耐药基因。厌氧消化后，沼液中的耐药基因绝对丰度提高但耐药基因相对丰度大幅下降。抗生素菌渣中水解细菌的最小抑菌浓度是沼液中水解细菌的32倍-192倍，定性评价抗生素菌渣中细菌为耐药菌，沼液中细菌为敏感菌。沼液作为抗生素菌渣生物处理的产物，其耐药性是安全可控的。 本研究构建了以表型耐药为基础的抗生素菌渣处理产物安全性评价体系，为菌渣处理产物中细菌在多种抗生素中的耐药水平设定了阈值。该系统固体减量化率高于95%，能够实现能量自给甚至对外供能，吨菌渣投资成本为12.6±1.0万元，吨菌渣运行成本为109.3±5.3元。本研究构建的抗生素菌渣处理工艺安全可靠、经济高效，实现了抗生素菌渣的无害化、减量化和资源化。
Antibiotic fermentation residues (AFRs) are the primary hazardous wastes in active pharmaceutical ingredients enterprises, and 1.5 million tons – 2 million tons AFRs are generated in China every year. High concentrations of antibiotics and antibiotic resistance genes (ARGs) in AFRs may cause spread of antibiotic resistance in the treatment process. AFRs have high water content, high organic matter content, low C/N ratio. Single technology cannot meet requirements of treatment of AFRs. In this study, streptomycin fermentation residue (SFR) and penicillin fermentation residue (PFR) were selected as typical AFRs. First, we developed a process including hydrothermal pretreatment, deep dewatering, anaerobic digestion, and pyrolysis for AFRs. Second, we evaluated the antibiotic resistance of processing products from the two aspects of ARGs and phenotypic resistance. Third, we calculated the investment cost and treatment cost of this treatment process based on material balance. Hydrothermal pretreatment improved the dewatering and biodegradation of AFRs. After hydrothermal pretreatment of 180 ?C, the particle sizes of AFRs were reduced to 20 μm – 30 μm, and more than 80% of bound water in AFRs was converted to free water. The methane yields of AFRs were increased by 5 times. After hydrothermal pretreatment of 180 ?C for 30 min, deep dewatering and inactivation of residual antibiotics were achieved in 10 varieties of AFRs in five categories. Upflow anaerobic sludge bed coupled with side-stream chemical nitrogen removal was developed, and 70% – 75% of organic matter in the hydrothermally treated AFRs filtrate were recovered in the form of biogas and 70% – 88% of ammonia nitrogen were removed. More than 80% of organic matter in the hydrothermally treated AFRs filter cake can be recovered by pyrolysis. The biochar produced by pyrolysis of 600 ?C met the standard of Grade III. The residual antibiotics in the SFR and PFR were below 1 μg/g when the hydrothermal temperature were above 140 ?C. The absolute abundance of ARGs in AFRs decreased by 2.4 logs – 7.4 logs after hydrothermal treatment of 180 ?C. No ARGs was detected in AFRs at pyrolysis temperature above 400 ?C. After anaerobic digestion, the absolute abundance of ARGs in digestate increased, but relative abundances of ARGs in digestate significantly decreased. The minimum inhibitory concentrations of bacteria in AFRs were about 32-fold – 192-fold more than that in digestates. The bacteria in AFRs were antibiotic resistant bacteria, and the bacteria in digestate were antibiotic susceptible bacteria. The antibiotic resistance of digestate was acceptable. This study developed a safety evaluation system based on phenotypic resistance for processing products of AFRs, and set threshold values of antibiotic resistance for bacteria in processing products of AFRs. The total mass reduction efficiency of this system was higher than 95%. The system can achieve energy self-sufficiency. The investment cost and treatment cost of this system was 126000 ± 10000 ?/t AFR and 109.3 ± 5.3 ?/t AFR, respectively. This system was safe, economical, and efficient for treating AFRs.
