Detection and quantification of enteroviruses in coastal seawaters from Bohai Bay,Tianjin,China

An 8-month survey was conducted to detect and quantify enteroviruses in Tianjin coastal seawaters of Bohai Bay to assess coastal water quality. Ten water samples were collected from Bohai Bay for the detection and quantification of enteroviruses by conventional reverse transcription polymerase chain reaction （RT-PCR） and SYBR Green real-time quantitative RT-PCR （qRT-PCR）. Total viral nucleic acid was extracted from 500 mL of seawater samples concentrated by Centricon plus-70 centrifugal filter devices. The viral recovery rate was 29.1% based on viral seeding study. The centrifugal ultrafiltration method applied is effective for viral recovery from small volume of polluted water, which may have broader applications to monitoring human virus in aquatic environment. Our results indicated that there was a severe viral contamination in seawater of Bohai Bay. Enteroviruses were detected at concentrations ranging from 1.7 × 10^6 to 6.3 × 10^7 copies/L by qRT-PCR. Sequencing analyses identified that all of the twenty clones as poliovirus type 2. This is the first quantitative report of human viruses in coastal waters of a metropolitan city in China. This study emphasized the importance for the local and central governmertts to monitor and assess the water quality.

Numerical Analysis of the Tunnel-Train-Air Interaction Problem in a Tunnel with a Double-Hat Oblique Hood

The tunnel-train-air interaction problem is investigated by using a numerical method able to provide relevant information about pressure fluctuations,aerodynamic drag characteristics and the“piston wind”effect.The method relies on a RNG k-εtwo-equation turbulence model.It is shown that although reducing the oblique slope can alleviate the pressure gradient resulting from initial compression waves at the tunnel entrance,the pressure fluctuations in the tunnel are barely affected;however,a large reduction of micro-pressure wave amplitudes is found outside the tunnel.In comparison to the case where no tunnel hood is present,the amplitudes of micro-pressure waves at 40 m from the tunnel reach an acceptable range.The aerodynamic drag of the head and tail fluctuates greatly while that of the intermediate region undergoes only limited variations when the high-speed train passes through the double-hat oblique tunnel.It is shown that the effects of the oblique slope of the portal on the aerodynamic drag can almost be ignored while the train speed plays an important role.

Responses of microbial interactions to elevated salinity in activated sludge microbial community

Biological treatment processes are critical for sewage purification,wherein microbial interactions are tightly associated with treatment performance.Previous studies have focused on assessing how environmental factors(such as salinity)affect the diversity and composition of the microbial community but ignore the connections among microorganisms.Here,we described the microbial interactions in response to elevated salinity in an activated sludge system by performing an association network analysis.It was found that higher salinity resulted in low microbial diversity,and small,complex,more competitive overall networks,leading to poor performance of the treatment process.Subnetworks of major phyla(Proteobacteria,Bacteroidetes,and Chloroflexi)and functional bacteria(such as AOB,NOB and denitrifiers)differed substantially under elevated salinity process.Compared with subnetworks of Nitrosomonadaceae,Nitrosomonas(AOB)made a greater contribution to nitrification under higher salinity(especially 3%)in the activated sludge system.Denitrifiers established more proportion of cooperative relationships with other bacteria to resist 3%salinity stress.Furthermore,identified keystone species playing crucial roles in maintaining process stability were dynamics and less abundant under salinity disturbance.Knowledge gleaned from this study deepened our understanding of microbial interaction in response to elevated salinity in activated sludge systems.

Characterization of bacterial community dynamics in a full-scale drinking water treatment plant

Understanding the spatial and temporal dynamics of microbial communities in drinking water systems is vital to securing the microbial safety of drinking water.The objective of this study was to comprehensively characterize the dynamics of microbial biomass and bacterial communities at each step of a full-scale drinking water treatment plant in Beijing,China.Both bulk water and biofilm samples on granular activated carbon（GAC） were collected over 9 months.The proportion of cultivable cells decreased during the treatment processes,and this proportion was higher in warm season than cool season,suggesting that treatment processes and water temperature probably had considerable impact on the R2 A cultivability of total bacteria.16 s rRNA gene based 454 pyrosequencing analysis of the bacterial community revealed that Proteobacteria predominated in all samples.The GAC biofilm harbored a distinct population with a much higher relative abundance of Acidobactena than water samples.Principle coordinate analysis and one-way analysis of similarity indicated that the dynamics of the microbial communities in bulk water and biofilm samples were better explained by the treatment processes rather than by sampling time,and distinctive changes of the microbial communities in water occurred after GAC filtration.Furthermore,20 distinct OTUs contributing most to the dissimilarity among samples of different sampling locations and 6 persistent OTUs present in the entire treatment process flow were identified.Overall,our findings demonstrate the significant effects that treatment processes have on the microbial biomass and community fluctuation and provide implications for further targeted investigation on particular bacteria populations.

Insights from metagenomic,metatranscriptomic,and molecular ecological network analyses into the effects of chromium nanoparticles on activated sludge system

The objectives of this study were to investigate the influence of chromium nanoparticles(Cr NPs)on the nitrogen and phosphorus removal performance and the bacterial structures of an activated sludge(AS)system.Also,we through molecular ecological networks(MENs)discussed the bacterial interactions.At last we researched the change of the functional genes and their expression patterns related to nitrogen and phosphorus removaT in an AS system.The results showed that long-term exposure to 1 mg/L Cr NPs significantly promoted the denitrifying process and phosphorus removal in the AS system.The relative abundance of denitrifying and phosphorus removal microorganisms,such as Denitratisoma,Thauera,Dechloromonas,and Defluviicoccus,increased significantly.Candidatus Accumulibacter,well-known as polyphosphate-accumulating organisms(PAOs),increased significantly;the relative abundance of Candidatus Competibacter,known as glycogen-accumulating organisms(GAOs),decreased significantly.Furthermore,metagenomic and metatranscriptomic analysis revealed that most of the genera related to denitrifying and phosphorus removal had greatly increased,according to the quantities of denitrifying and phosphorus genes,and the corresponding transcription likewise greatly increased.Lastly,MENs analysis showed that although the overall network became smaller and looser in the presence of Cr NPs,the microbial connections among members related to nitrogen and phosphorus removal were enhanced.The abundance increases of denitrifiers and PAOs,and their increased transcription of functional genes,together with the enhanced interactions may be associated with the promotion of the denitrifying process and phosphorus removal.

Preparation and characterization of a novel blue-TiO_(2)/PbO_(2)-carbon nanotube electrode and its application for degradation of phenol

In this study,we fabricated a blue-TiO_(2)/PbO_(2)-carbon nanotube (CNT) electrode in which blue TiO_(2)nanotube arrays (blue-TNA) served as the substrate for PbO_(2)-CNT eletrodeposition.Scanning electron microscope (SEM) showed compact surface structure of the electrode.The β-PbO_(2)crystal structure was detected by X-ray diffraction (XRD).The distribution of Pb,O,C,and Na elements on the electrode surface have been confirmed by X-ray photoelectron spectroscopy (XPS).Blue-TiO_(2)/PbO_(2)-CNT electrode had higher response current (213.12mA),larger active surface area and lower charge transfer resistance (2.22Ω/cm^(2)) than conventional TiO_(2)/PbO_(2)-CNT electrode.The influences of current density,initial phenol concentration,initial solution pH,and Na2SO_(4)concentration on the electrochemical oxidation of phenol have been analyzed.The results showed that the 100 mg/L phenol could be destroyed completely after 210 min,and chemical oxygen demand (COD) removal rate was 89.3%within 240 min.Additionally,the electrode showed long actual lifetime (5468.80 hr) and low energy consumption (0.08 kWh/gCOD).A phenol degradation mechanism was proposed by analyzing the intermediate products with high-performance liquid chromatography-mass spectrometry (HPLC-MS).Importantly,the blue-TiO_(2)/PbO_(2)-CNT electrode exhibited superior stability and high degradation efficiency after 15 times reuse,demonstrating its promising application potential on phenol-containing wastewater treatment.