Effect of electrical stimulation on the fate of sulfamethoxazole and tetracycline with their corresponding resistance genes in three-dimensional biofilm-electrode reactors

Abstract

Three-dimensional biofilm-electrode reactors (3D-BERs), which possess a large effective area to drive the reductive degradation of contaminants, have recently attracted attention for wastewater treatment. There have been few studies of the potential and risks of the application of this system on the removal of antibiotics. Here four 3D-BERs were designed to initially assess the potential for electrical stimulation to remove sulfamethoxazole (SMX), tetracycline (TC) and chemical oxygen demand, and to study the fate of the corresponding antibiotic resistance genes. The results indicated that the 3D-BER could significantly reduce antibiotic concentrations in wastewater, achieving removal rates of 88.9-93.5% and 89.3-95.6% for SMX and TC, respectively. The concentrations of target genes (sulI, sulII, sulIII, tetA, tetC, tetO, tetQ, and tetW) in a granular-activated carbon (GAC) cathode were higher than those in a GAC anode in the 3D-BR (reactor with biological sludge and no voltage) and 3D-BER. An obvious increasing trend in the relative abundances of all target genes was observed in the GAC. A low current density could not increase the development of sul and tet genes in the 3D-BER. The total resistance was in the following order: 3D-BER > 3D-BR > 3D-ER (reactor with 0.8 V and without biological sludge). In addition, the dehydrogenase activity of the microorganisms in the 3D-BER was significantly higher than in the 3D-BR (p < 0.05). High-throughput sequencing revealed that the microbial communities and relative abundance at the phyla level were affected by current stimulation.

Vertical up-flow constructed wetlands exhibited efficient antibiotic removal but induced antibiotic resistance genes in effluent

“…10 Oenanthe javanica was planted in the top layer and grew vigorously. The synthetic domestic wastewater containing glucose (0.225 g L -1 ), KH 2 PO 4 (0.004 g L -1 ), NH 4 Cl (0.020 g L -1 ), NaCl (0.15 g L -1 ), and 0.20 mL concentrated trace element solution (Cao et al, 2015;Zhang et al, 2016). The synthetic domestic was fed continuously into the VUF-CWs at the bottom inlet using peristaltic pumps.…”

“…Similar with previous studies, the abundance of sulI was higher than that of the sulII and sulIII genes (Ji et al, 2012;Nolvak et al, 2013). The different abundance of sul genes in the CWs were mainly attributed to their specific acquisition mechanisms (McKinney et al, 2010;Zhang et al, 2016).…”

Removal of antibiotics from wastewater and its problematic effects on microbial communities by bioelectrochemical Technology: Current knowledge and future perspectives

“…revealed the method of degradation of SMX 6.0 mgL -1 in a microbial electrolytic cell within seven days. Another study by Zhang et al [24] observed that the removal rate of 200μgL -1 of sulfamethoxazole (SMX) in a three-dimensional biofilm electrode reactor (3D-BER). The system reached 85.5 ̶ 90% removal with hydraulic retention time (HRT) of 40 h. While the multipurpose treatment of solid-phase mixtures (granular activated carbon), Song et al [25] demonstrated that the removal performance of antibiotics in 3-Dimensional biofilm electrode reactors (3DBER), in solid phase environment and integration possibilities with other technologies, as shown in Table 1.…”

Degradation characterization and pathway analysis of chlortetracycline and oxytetracycline in a microbial fuel cell

“…16 The MFC can convert energy and produce electricity while degrading organic matter, 17,18 such as easily degradable 19,20 and bio-refractory organics. 21,22 Several studies have recently focused on the degradation of TCs by MFC 23,24 to improve TC removal. However, the characterization and degradation mechanisms of the different kinds of TCs by MFC remain unknown.…”