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Samples collected in summer and winter were analyzed by high-throughput sequencing technology to reveal differences in the microbial community diversity of activated sludge at different temperatures in a municipal wastewater treatment plant of Northern China. A total of 36,438 validated reads were obtained from the samples, and the bacteria belonged to 25 phyla and 139 genera. The Shannon diversity index decreased from 5.367 in summer to 5.168 in winter. During summer, the dominant phylum wasProteobacteria(50.5%), while it wasBacteroidetesduring winter (40.5%). At the genus level,Chitinophagawas most abundant during summer (8.7%), whileHaliscomenobacter(2.8%) had the greatest abundance in winter. Almost all nitrogen and phosphorus removal-related functional microbes, includingThiobacillus(denitrifying bacteria),Rhodocyclus(phosphorus-accumulating bacteria), andNitrosomonadaceae(ammonia-oxidizing bacteria), showed significantly higher abundance in summer than winter. Conversely, cryophilic microbial abundance was significantly higher in winter than summer. [ABSTRACT FROM PUBLISHER]

Activated carbon (AC) developed from loofah sponge with phosphoric acid activation was applied to absorb cefalexin (CEX) in aqueous solution. AC was characterized by N2adsorption–desorption isotherms and Fourier transform infrared spectroscopy (FTIR). Factors influencing the adsorption process were investigated. The equilibrium adsorption isotherms and kinetics of CEX were also studied. The results showed that AC prepared from loofah sponge had rough surface and abundant pores. The determination results of specific surface area (810.12 m2/g) and average pore size (5.28 nm) suggested the high adsorption capability. At low concentration, the AC could adsorb about 95% of CEX. The adsorption effect was independent of the temperature and pH. The maximum adsorption amount of CEX was about 55.11 mg/g at 308 K. The equilibrium data agreed well with Freundlich isotherm equation (R2 = 0.9957) at 308 K, which indicated multilayer adsorption. FTIR analysis suggested the existence of phosphorus-containing functional groups, C–O bond, and C=C bond on the surface of AC of which the peak intensity of AC after adsorption was slightly lower after adsorption, indicating that the AC surface groups interacted with or were covered by the CEX species. [ABSTRACT FROM AUTHOR]

Activated carbon (AC) prepared from luffa sponge was firstly used as an adsorbent to remove Cr(VI) from aqueous solution. The Cr(VI) adsorption behaviors of AC under different conditions, including initial Cr(VI) concentration, quantity of AC, solution pH, and temperature were investigated. The optimal conditions for adsorption of Cr(VI) by AC were pH = 1, initial Cr(VI) concentration = 80 mg/L,T = 303 K, and AC content = 1.6 g/L. The adsorption kinetics could be described by the pseudo-second-order model. Fourier transform infrared spectroscopy was used to investigate the sorption mechanism. Some functional groups such as C–O and O–H were formed on the carbon surface, which could then react with Cr(VI). The surface structure of AC before and after adsorption was analyzed by scanning electronic microscopy. Adsorbed ions choked some of the pores in AC after adsorption. The Brunauer–Emmett–Teller surface area and average pore size of the AC were 834.13 m2/g and 5.17 nm, respectively. The maximum adsorption of Cr(VI) by AC was 149.06 mg/g, which makes AC prepared from luffa sponge promising for removing Cr(VI) from wastewater. [ABSTRACT FROM AUTHOR]

The performance and microbial community changes of an activated sludge sequencing batch reactor were evaluated after exposure to trimethoprim for 51 days. The average chemical oxygen demand, ammonia nitrogen, phosphorus efficiencies were 88.6% ± 0.56%, 90.47% ± 0.29% and 64.25% ± 1.12%, respectively. The protein and polysaccharide contents increased with increasing trimethoprim concentration to protect the cells from the unfavorable conditions. The chemical composition of extracellular polymeric substances increased. For denitrifying bacteria, the read numbers of Pseudomonas , Flavobacterium and Bacillus were both significantly increased from Day 1 to 25 and sharply decreased by Day 50 ( p < 0.05), which is consistent with the tendency of Planctomyces (Anammox). The read number of Paracoccus displayed an increasing trend, whereas Nitrospirales, Nitrospira (nitrite oxidizer) and Nitrosomonadaceae (ammonia oxidizer) were significantly decreased ( p < 0.05). The read number of Rhodocyclaceae (phosphorus oxidizer) was significantly decreased from Day 1 to 25 and sharply increased by Day 50 ( p < 0.05). [ABSTRACT FROM AUTHOR]

An activated sludge sequencing batch reactor (SBR) was fed with synthetic wastewater containing ofloxacin (OFL) for 52 days to study the overall performance of the SBR, the characteristics of extracellular polymeric substances (EPS) and the bacterial community shift. Removal efficiencies of chemical oxygen demand, ammonia nitrogen, phosphorus and OFL were maintained at 90%, 96%, 80% and 65%, respectively. The EPS contents increased with increasing OFL concentration because more EPS was secreted to protect cells from OFL damage. Moreover, the EPS compositions shifted. For denitrifying bacteria, the read number of Pseudomonas and Bacillus sharply decreased initially ( p < 0.05) and increased from Day 25 to Day 50, which agreed with the tendency of Nitrosomonadaceae (ammonia oxidizer), while Paracoccus significantly decreased ( p < 0.05). The read number of Rhodocyclaceae , a phosphorus-accumulating bacterium, increased. Other functional microbes such as Nitrospirales (nitrite oxidizer) and Planctomyces (anammox) sharply decreased under OFL pressure ( p < 0.05). [ABSTRACT FROM AUTHOR]