• Energy Research

A feasible and readily available source of hydrogen‐producing acetogens (HPAs) was developed by obtaining microflora D83 dominated by butyrate‐oxidizing HPAs through enrichment and subculture of anaerobic sludge with the use of butyric acid. The effect of bioaugmentation of D83 both on methane production through glucose fermentation and molasses wastewater treatment was evaluated. At a bacterial number‐to‐activated sludge ratio of 1:9, inoculation of microflora D83 could enhance methane yield and production rate from glucose by a factor of 2.1 and 2.0, respectively. In treatment of normal molasses wastewater, chemical oxygen demand (COD) removal efficiency improved from 75.6% to 88.2%, and the accumulated methane yield and methane yield obtained through COD removal increased by a factor of 2.3 and 2.0, respectively. Hydrogen‐producing acetogenesis is apparently a rate‐limiting step in methanogenesis because bioaugmentation of HPAs during methane production improved not only hydrogen‐producing acetogenesis but also hydrolysis/acidogenesis and methanogenesis. © 2017 American Institute of Chemical Engineers Environ Prog, 37: 367–374, 2018

The aim of this work was to study the responses of aerobic granulation process to antibiotics and investigate the antibiotics and antibiotic-resistant bacteria (ARB) removal and transport. Results showed that aerobic granular sludge (AGS) was dominant in the bioreactor at day 45, and the relatively high protein content from tightly bound extracellular polymeric substances (TB-EPS) facilitated aerobic granulation and maintained biomass stabilization. The protein contents in EPS and TB-EPS were positively correlated with relative hydrophobicity, thereby improving the adsorption capacity among hydrophobic particles. The chemical oxygen demand (COD), NH3-N, and total N removal efficiencies were 98.0%, 97.0%, and 92.4%, respectively. Five antibiotics, including kanamycin, tetracycline, ciprofloxacin, ampicillin, and erythromycin, were examined in piggery wastewater, with concentrations up to the concentration range of 29.4-44.1 µg/l, and the total antibiotics removal rate reached up to 88.4% ± 4.5%. A total of 5.2% of the total antibiotics were discharged from bioreactor, and 62.5% of the total antibiotics were degraded, and 32.3% of total antibiotics were adsorbed by aerobic granules. The presence of antibiotics rarely exhibited an influence on AGS formation, and the relatively high microbial activity of aerobic granules was beneficial to antibiotics removal. The ARB removal rate increased up to 89.4% ± 3.3%, but a large amount of ARB was enriched in aerobic granules.