[High-Throughput Sequencing Analysis of Microbial Communities in Summertime Atmospheric Particulate Matter in Hefei City].

The composition, physical and chemical properties, sources, and temporal and spatial changes in airborne particulate matter have been extensively investigated in previous studies. However, less is known about bioaerosols, which are mainly composed of bacteria and fungi and constitute up to 25% of the total airborne particulate matter. In this study, we used inductively coupled plasma mass spectrometry and ion chromatography to determine the concentrations of trace elements and water-soluble ions in atmospheric particulates, respectively. These analyses were combined with high-throughput sequencing methods and real-time quantitative polymerase chain reaction to analyze the microbial compositions in PM1.0, PM2.5, and PM10 samples, which were collected from July to September in Hefei City. The results showed that there were no significant differences in the bacterial community diversity across the three size fractions (analysis of variance (ANOVA), P>0.05). The bacterial and fungal community diversities on sunny days were lower than those on rainy days, and the bacterial community diversity in all samples was significantly higher than the fungal community diversity (ANOVA, P<0.01). The predominant bacterial phyla were Proteobacteria (46.19%), Firmicutes (33.42%), Bacteroidetes (10.99%), Cyanobacteria (3.33%), and Actinobacteria (2.11%). Ascomycota (73.23%), Basidiomycota (5.78%), Mortierellomycota (3.41%), and Mucoromycota (0.10%) were the dominant fungal phyla. Our results indicated that soils, plant leaves, and animal feces were the dominant sources of airborne bacterial communities in Hefei City, and the main sources of the fungal communities were plant leaves and soils. The bacterial community was mainly affected by K, Pb, Al, Fe, Mg, Ca, Na+, NO2-, and wind speed, and the main influencing factors of the fungal community were V, Mn, Sr, NO2-, NO3-, Na+, Cl-, the air quality index, and PM10. In addition, nine specific bacteria and fungi that are linked to human health risks were identified, including Acinetobacter, Streptococcus, Enterobacter, Pseudomonas, Delftia, Serratia, Trichoderma, Alternaria, and Aspergillus, which can lead to a wide range of diseases in humans and other organisms. The research results are helpful for revealing the various characteristics of airborne microbial communities, their influencing factors, and their impacts on human health, and are an important reference for subsequent research and the formulation of government policies.

[Fine Particulate Emission Characteristics of an Ultra-Low Emission Coal-Fired Power Plant].

Since the introduction of ultra-low emissions, the characteristics of particulate matter (PM) emissions from coal-fired power plants have changed. We quantitatively evaluate the emission characteristics of each component in PM and the impact of purification equipment by analyzing three ultra-low emission units of coal-fired power plants (FP1, FP2, and FP3). A DGI was used to sample particles from the wet flue gas desulfurization (WFGD) unit and wet electrostatic precipitator (WESP) inlet and outlet, which were then analyzed by various methods. The results showed that the mass concentrations of PM1, PM2.5, and PM10 discharged from the outlets of the three units were 0.25-0.38, 0.31-0.42, and 0.42-0.57 mg·m-3, respectively, and that the mass concentration of PM10 discharged under the two kinds of units was equivalent. However, there were differences in the particle size distribution and composition of the particles. In comparison to the FP1 and FP2 units, the PM2.5/PM10 ratio of the FP3 unit was the highest. A possible reason for this is that the unit was equipped with a WESP, which can better remove particle sizes of 2.5 µm or more. The total concentrations of water-soluble ions in PM2.5 discharged from the FP2 and FP3 units were 0.20 and 0.06 mg·m-3, respectively. The water-soluble ions emitted from the FP2 unit were mainly Ca2+ and SO42-, whereas those mainly emitted from the FP3 unit were NH4+ and SO42-. Analysis of the PM from the WFGD import and export of the FP2 unit showed that the WFGD process increased the water-soluble ion discharge by entraining the desulfurization slurry containing limestone and gypsum. Addition of a WESP after WFGD can effectively remove PM2.5 and PM10 particles and reduce the influence of water-soluble ions on the atmospheric environment.

[Evaluation of MACC Reanalysis Ozone Data over China Using Ground-based and AIRS Satellite Observations].

A comparative analysis was conducted using total ozone products derived from monitoring atmospheric composition and climate (MACC) reanalysis data validated with ozone data from the atmospheric infrared sounder (AIRS) satellite and ground-based ozone measurements. The results indicate that the relative deviation of total ozone from the MACC reanalysis data and the ground-based ozone total data is controlled within 17%, and all of the correlation coefficients were between 0.79 and 0.97. The total ozone values from the MACC reanalysis data showed good consistency with the ground-based ozone measurements. With respect to the spatial distribution of multi-year averages, the relative deviation of total ozone values in the MACC reanalysis data and the AIRS satellite data was between -3% and 5%. The total ozone values in the MACC reanalysis data were higher than those from AIRS measurements for the Qinghai-Tibet Plateau and the coastal areas of South China, and were lower for northeast China. Furthermore, the seasonal variations in total ozone values in the MACC reanalysis data were consistent with AIRS data. At Mt. Waliguan station, the monthly averaged trends for near-surface ozone in the MACC reanalysis data were also consistent with surface ozone concentrations; the MACC reanalysis data reflect the observed trends for surface-based ozone measurements in spring, summer, and autumn, but show a large deviation in winter.

[Optimization for Microthrix parvicella Quantitative Processing of Fluorescence in situ Hybridization (FISH)].

Precise quantification of Microthrix parvicella, which is identified as a dominated filamentous bacterium of bulking sludge in the worldwide, is essential for bulking investigation and related control strategies. However, quantitative processing based on fluorescence in situ hybridization (FISH) is prone to interference due to the specific characteristics of Microthrix parvicella (hydrophobic surface with thick cell wall). Our study focused on pretreatment and process optimization to show that the proportion of Microthrix parvicella was increased from 1.12% to 96.70% benefited by lysozyme (36000 U·mL-1), high probe concentration (4.5 ng·µL-1) and longer hybridization time (4 h) employed, mapping with the results of q-PCR method and Eikelboom & Jenkins Observation.

[Investigation for Filamentous Bacteria Community Diversity in Activated Sludge Under Various Kinds and Concentration Conditions of Antibiotics].

Three kinds of synthetic antibiotic (spiramycin, oxytetracycline, streptomycin) wastewater were continuously treated by parallel aerobic biofilm reactors for 6 months, respectively. Sludge bulking phenomenon caused by overgrowth of filamentous bacteria was observed under long-term high rbCOD and high C/N conditions in all reactors as showed by the Eikelboom and Jenkins examinations. The qualitative analysis of filamentous bacterial population in the biofilm and suspended sludge using fluorescence in situ hybridization (FISH) showed that the dominated filamentous bacteria in the bioreactor were N. limicola II and Thiothrix II. Under conditions of different antibiotic concentrations (5 mg x L(-1), 25 mg x L(-1)), there was no obvious change in the COD removal efficiency of the parallel reactors, while the NH4+ -N concentration (about 20 mg x L(-1)) occurred under high streptomycin concentration. The filamentous bacteria abundance was reduced with the increasing antibiotic concentration, especially significant for N. limicola II. Terramycin had a significant inhibitory effect on filamentous bacteria population, followed by Streptomycin and Spiramycin.