Yu Kai-Feng, Li Peng, Li Han, Zhang Bo, Yang Jun, Huang Fu-Yi, Li Rui, He Yiliang
School of Environmental Science & Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China.
Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China.
J Hazard Mater. 2021 Mar 15;406:124295. doi: 10.1016/j.jhazmat.2020.124295. Epub 2020 Oct 16.
Coagulation has been accepted as a cost-effective and environmental-friendly method to remove pollutants. In our recent work, two coagulants of polyaluminum chloride (PAC) and polyaluminum ferric chloride (PAFC) with dosage gradients, and one coagulant aid of anionic polyacrylamide (PAM) were used to investigate their potential to remove particle-associated (PA) and free-living (FL) ARGs and MGEs detected by high throughput qPCR (HT-qPCR) method. The results indicated that the maximum removal efficiencies of PA- and FL-ARGs (4.67- and 3.18-logs) were obtained at the PAFC dosage of 50.0 mg/L. Excessive PAFC dosage can hamper the removal of size-fractionated ARGs. As PAC aid, anionic PAM (1.0 mg/L) had limited effects to promote the removal of PA-ARG, while FL-ARG removal was enhanced by 0.34 log at the PAC dosage of 50.0 mg/L. The fitted curves suggested that the optimal chemical dosages of PAC, PAFC and PAC coupled with PAM in the removal of total ARGs and MGEs were 40.5, 64.7 and 50.0 mg/L, respectively. In addition, we found that much more coagulants were needed to remove FL-ARGs compared to that of PA-ARGs. The removal efficiencies of size-fractionated ARGs by flocculation can be affected by coagulant type, dosage, coagulant aid, Zeta potential and microorganism lifestyle (PA or FL).
混凝已被公认为是一种去除污染物的经济高效且环境友好的方法。在我们最近的工作中，使用了两种具有剂量梯度的混凝剂，即聚合氯化铝（PAC）和聚合氯化铁（PAFC），以及一种助凝剂阴离子聚丙烯酰胺（PAM），来研究它们去除通过高通量定量聚合酶链反应（HT-qPCR）方法检测到的颗粒结合型（PA）和自由生活型（FL）抗生素抗性基因（ARGs）及移动遗传元件（MGEs）的潜力。结果表明，在PAFC剂量为50.0 mg/L时，PA-ARGs和FL-ARGs的最大去除效率分别达到4.67和3.18个对数级。PAFC剂量过高会阻碍不同粒径ARGs的去除。作为PAC的助凝剂，阴离子PAM（1.0 mg/L）对促进PA-ARG的去除效果有限，而在PAC剂量为50.0 mg/L时FL-ARG的去除提高了0.34个对数级。拟合曲线表明，在去除总ARGs和MGEs方面，PAC、PAFC以及PAC与PAM联用的最佳化学剂量分别为40.5、64.7和50.0 mg/L。此外，我们发现与PA-ARGs相比，去除FL-ARGs需要更多的混凝剂。絮凝对不同粒径ARGs的去除效率会受到混凝剂类型、剂量、助凝剂、Zeta电位和微生物生活方式（PA或FL）的影响。
