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Microbes play important roles during river remediation and the interaction mechanism illustration between microorganisms and sewage is of great significance to improve restoration technology. In this study, micro-nano bubble and submerged resin floating bed composite technology (MBSR) was firstly used to restore two black and stinking urban rivers. After restoration, the water pollution indices such as dissolved oxygen (DO), ammonia nitrogen (NH 4 + -N), total phosphorous (TP), chemical oxygen demand (COD Cr ), water clarity, and the number of facial coliform were significantly improved. Microbial community composition and relative abundance both varied and more aerobic microbes emerged after remediation. The microbial changes showed correlation with DO, NH 4 + -N, TP and COD Cr of the rivers. In summary, the MBSR treatment improved the physiochemical properties of the two black and stinking urban rivers probably through oxygen enrichment of micro-nano bubble and adsorption of submerged resin floating bed, which thereby stimulated functional microbes to degrade pollutants. [ABSTRACT FROM AUTHOR]

Wastewater treatment plants are thought to be potential reservoirs of antibiotic resistance genes. In this study, GeoChip was used for analyzing multiple antibiotic resistance genes, including four multidrug efflux system gene groups and three β-lactamase genes in ten large-scale membrane bioreactors (MBRs) for municipal wastewater treatment. Results revealed that the diversity of antibiotic genes varied a lot among MBRs, but about 40% common antibiotic resistance genes were existent. The average signal intensity of each antibiotic resistance group was similar among MBRs, nevertheless the total abundance of each group varied remarkably and the dominant resistance gene groups were different in individual MBR. The antibiotic resistance genes majorly derived from Proteobacteria and Actinobacteria. Further study indicated that TN, TP and COD of influent, temperature and conductivity of mixed liquor were significant ( P < 0.05) correlated to the multiple antibiotic resistance genes distribution in MBRs. [ABSTRACT FROM AUTHOR]

A newly isolated and identified Diaphorobacter polyhydroxybutyrativorans strain (SL-205) was employed to enhance the denitrification performance of a laboratory-scale solid-phase denitrification (SPD) reactor using poly (3-hydroxybutyrate- co -3-hydroxyvalerate) (PHBV) as a carbon source, and dynamic variations in microbial communities in the reactor were investigated. Results indicated that bioaugmentation with strain SL-205 enabled rapid reactor startup and improved denitrification performance relative to the reactor inoculated with activated sludge. Illumina sequencing revealed that bioaugmentation also significantly increased Proteobacteria abundance along with increased influent nitrate loading. Additionally, two genera of PHBV-degrading denitrifers, Diaphorobacter and Acidovorax , exhibited higher abundance, and elevated expression of denitrification-associated genes ( narG, nirK, and nirS ) was observed following bioaugmentation relative to the control at influent nitrate loading ranging from 1.28 g N/(L·d) to 1.6 g N/(L·d). [ABSTRACT FROM AUTHOR]

• Hydrolysis acidification reactor exhibited high decolorization rate at high salinity. • High salinity significantly increased EPS, SMP and VFAs. • The biodegradability of the synthetic textile wastewater was increased. • The effect of salinity on the bacterial consortium during HA was analyzed. Hydrolysis acidification (HA) is a classical method for synthetic textile wastewater treatment. However, the salinity effect on the functional mechanism of the microorganisms carrying out HA has rarely been researched. In the present study, the salinity effect on the dye removal efficiency was investigated, and the soluble microbial products (SMP), extracellular polymeric substances (EPS), and microbial community were analyzed at different salinities. The dye and COD removal rates in the HA reactor decreased with increasing salinity. Volatile fatty acids (VFAs) accumulated. The remarkable increases in SMP and EPS were found at high salinity, mainly because more polysaccharides were synthesized than protein. In addition, sequencing analysis showed that high salinity altered the microbial community structure, and Lactococcus , Raoultella and Enterococcus were the decolorizing bacteria at high salinity. This work will improve the understanding of the influence of salinity on the removal efficiency and microbial community during HA. [ABSTRACT FROM AUTHOR]