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Many studies have shown that both Chironomid larvae and Microcystis aeruginosa would form disinfection byproducts (DBPs) under chlorination or chloramination. However, in the natural state, Microcystis aeruginosa and Chironomid larvae exist together. DBPs of chlorination between Chironomid larvae and Microcystis aeruginosa were widely assumed to be "black box." This study focused on effects of Microcystis aeruginosa on DBP formation during the chlorination of Chironomid larvae metabolites. Results of the study suggest that the presence of Microcystis aeruginosa not only influences the concentration of DBPs from Chironomid larvae metabolism, but also changes the trend of individual DBPs. Results suggest that Microcystis aeruginosa may change the trend of chloropicrin (TCNM), and Microcystis aeruginosa may promote TCM, 1,1-DCP, 1,1,1-TCP, and TCNM formation, while inhibiting the accumulation of DCAA and TCAA. Results illustrate the mechanism of Microcystis aeruginosa participating in DBP formation during chlorination of Chironomid larvae. [ABSTRACT FROM AUTHOR]

The emission of nitric oxide (NO) to the atmosphere is a major environmental problem. To abate NO emission from the industrial flue gas, a rotating drum biofilter (RDB) was developed for the denitrifying removal of NO. After the start-up period, the RDB could effectively remove NO from the waste gas and the denitrifying removal efficiency could reach 85%. After the addition of CuII(EDTA) to the nutrients, the removal efficiency could increase to 99.1%. To improve the understanding of the relationship between the composition of bacterial population and the performance of the RDB, a denaturing gradient gel electrophoresis (DGGE) of polymerase chain reaction-amplified genes coding for 16S rRNA was used to analyze and determine the changes in bacterial communities in the RDB. Results showed that there was a slight change in microbial diversity after the addition of CuII(EDTA) to the nutrient solution, which led to an increase in NO removal efficiency. Eight major bands of 16S rRNA gene fragments obtained from the DGGE gels of biofilm samples were further purified, reamplified, cloned, and sequenced. Phylogenetic analysis identified sixteen types of micro-organisms in the RDB. Sequences of these fragments were compared with those listed in the database of the GeneBank (National Center for Biotechnology Information). Gene analysis of 16S rRNA showed that the major populations were Clostridium sp., β-proteobacterium, γ-proteobacterium, and Cytophaga-Flexibacteria-Bacteroides (CFB) groups. In addition, it was concluded that denitrification was caused by the organism with DNA represented by bands labelled G-5, G-6, and G-8. G-5 was related to a γ-proteobacterium, whereas those labeled G-6 and G-8 were related to a β-proteobacterium. [ABSTRACT FROM AUTHOR]

Background: The regions in the middle of nonstructural protein 2 (nsp2) of porcine reproductive and respiratory syndrome virus (PRRSV) have been shown to be nonessential for PRRSV replication, and these nonessential regions are different in various viral strains. Finding: In this study, the nonessential regions of the nsp2 of an attenuated vaccine strain (HuN4-F112) of highly pathogenic porcine reproductive and respiratory syndrome virus were identified based on an infectious cDNA clone of HuN4-F112. The results demonstrated that the segments of nsp2 [amino acids (aa) 480 to 667] tolerated deletions. Characterization of the mutants demonstrated that those with small deletions did not affect the viral growth on Marc-145 cells, but deletion of these regions led to earlier PRRSV replication increased (before 36 h after infectious in vitro). Conclusion: The functional roles of nsp2 variable middle region for PRRSV HuN4-F112 replication have been identified. Our results also suggested that none-essential region might be an ideal insertion region to express foreign gene in PRRSV genome. [ABSTRACT FROM AUTHOR]

Two runs of experiments were carried out to obtain an understanding of phosphorus release and uptake under the anaerobic condition and then the aerobic condition respectively. Under anaerobic condition, it was found that the extent of phosphorus release appeared to increase with the increase of the initial organic loading rate when the initial organic loading rate was up to 0.1 gSCOD/gMLSS. When the initial organic loading rate was higher than 0.1 gSCOD/gMLSS, the amount of phosphorus release per unit mass of MLSS reached nearly a same stationary value, and it seemed this is not affected by organic loading rate when there is external available substrate remained. In addition, the effect of NOx-N on the phosphorus release and uptake was also investigated, it was proved that the denitrifiers has an advantage over polyphosphate accumulating bacteria in competition for organic substrate under anoxic condition. Therefore, the existence of NOx-N is disadvantageous to the phosphorus release. Based upon the above investigations, the process configuration of membrane bioreactor (MBR) in combination with anaerobic phase was proposed to enhance the removal of phosphorus in treating domestic wastewater. During the experimental period of four months, average removals of 92.50% . 84.25% . 100% . 94.09% and 85.33% were achieved for COD, TP. SS, NH3 N and TN respectively. [ABSTRACT FROM AUTHOR]

The innovative process consists of biological unit for wastewater treatment and ozonation unit far excess sludge treatment. An aerobic membrane bioreactor (MBR) was used to trainee organics and nitrogen, and an anaerobic reactor was added to the biological wilt for the release of phosphorus contained at aerobic sludge to enhance the removal of phosphorus. For the excess sludge produced in the MBR, which was fed to ozone contact column and reacted with ozone, then the ozonated sludge was returned to the MBR for further biological treatment. Experimental results showed that this process could remove organics, nitrogen and phosphorus efficiently. and the removals for COD, NH3N. TN and TP were 93.17% , 97.57% . 82.77% and 79.5% . respectively. Batch teat indicated that the specific nitrification rate and specific denitrification rate of the MBR were 1.03 mg NH3N/(gMLSS·h) and 0.56 mg NOx-N/(gMLSS·h) and denitrification seems to be the rate-limiting step. Under the test conditions. the sludge- concentration in the MBR was kept at 5000-6000 mg/L. and the wasted sludge was oxonated at an ozone dosage of 0.10 kgO3/kgSS. During the experimental period of two months. no excess sludge was wasted. and a rein withdrawal of excess sludge was implemented. Through economic analysis. it was found that an additional ozonation operating carat for treatment of both wastewater and excess sludge was only 0.045 RUB Yunn(USD 0.0054)/m' wastewater. [ABSTRACT FROM AUTHOR]

In recent years, acute outbreaks of epizootic diarrhea have occurred on many swine farms in China. Although the putative causative virus of the disease was not isolated, the genomic sequence of porcine epidemic diarrhea virus (PEDV) was consistently detected from feces of diseased pigs by reverse transcription-PCR (RT-PCR). Here we report a complete genome sequence of PEDV which is apparently different from those of early PEDV circulated in Chinese swine herds. [ABSTRACT FROM AUTHOR]