Reason and control strategy for denitrification and anammox sludge flotation in nitrogen removal process: Mechanisms, strategies and perspectives.

Anaerobic biological treatment technology, especially denitrification and anaerobic ammonia oxidation (anammox) technology as mainstream process, played dominant role in the field of biological wastewater treatment. However, the above process was prone to sludge floating during high load operation and thereby affecting the efficient and stable operation of the system. Excessive production of extracellular polymeric substance (EPS) was considered to be the main reason for anaerobic granular sludge flotation, but the summaries in this area were not comprehensive enough. In this review, the potential mechanisms of denitrification and anammox sludge floatation were discussed from the perspective of granular sludge structural characteristics, nutrient transfer, and microbial flora change respectively, and the corresponding control strategies were also summarized. Finally, this paper indicated that future research on sludge flotation should focus on reducing the negative effects of EPS in sludge particles.

Promotion of nitrogen removal in a denitrification process elevated by zero-valent iron under low carbon-to-nitrogen ratio.

The nitrogen removal efficiency and distribution of microbial community in a denitrification process aided by zero-valent iron (ZVI) under low carbon-to-nitrogen ratio (C/N) were assessed in this study. Experimental results demonstrated that the nitrogen removal efficiency (TNRE) increased to 96.4 ± 2.72% and 63.3 ± 4.02% after continuous addition of ZVI with molar ratio of ZVI to nitrate (NO3--N) (ZVI/N) of 6 at C/N of 3 and 2, respectively, which was 4% and 7.7% higher than the blank one. Meanwhile, extracellular polymeric substance (EPS) could be used as electron transfer medium and endogenous carbon source for denitrification system and also the production of which increased by 28.43% and 53.10% under ZVI stimulation compared to the control group. Finally, a symbiotic system composed by autotrophic and heterotrophic denitrification bacteria was formed by aid of ZVI. This study proposed new insights into denitrification process improved by ZVI.

Novel Nsp2 deletion based on molecular epidemiology and evolution of porcine reproductive and respiratory syndrome virus in Shandong Province from 2013 to 2014.

Porcine reproductive and respiratory syndrome (PRRS) is an economically important swine disease affecting swine worldwide. In this study, a total of 385 samples were collected from Shandong pig farms during 2013 and 2014, when pigs were not inoculated with any vaccine. Results indicated that, out of 385 samples, 47 (12.21%) were PRRSV-RNA-positive. The gene sequence analysis of 12 ORF5, 12 ORF7, and 8 Nsp2 of these samples was used to determine the molecular epidemiology of PRRSV in different parts of China's Shandong Province. The phylogenetic tree based on these 3 genes indicated that the Chinese PRRSV strains could be divided into five subgroups and two large groups. The 8 study strains were clustered into subgroup IV, another 4 strains into subgroup I. The first 8 strains shared considerable homology with VR-2332 in ORF5 (96-97.5%), the other 4 strains shared considerable homology with JXA1 (94-98%). Phylogenetic tree of GP5 showed that the eight isolates formed a tightly novel clustered branch, subgroup V, which resembled but differed from isolate VR-2332. When examined using Nsp2 alone, the first 8 strains showed considerable homology with a U.S. vaccine strain, Ingelvac MLV (89.6-98.4%). One novel pattern of deletion was observed in Nsp2. The genetic diversity of genotype 2 PRRSV tended to vary in the field. The emergence of novel variants will probably be the next significant branch of PRRSV study.

Characterization and energy potential of food waste from catering service in Hangzhou, China.

Safe disposal of food waste is becoming an impending issue in China with the rapid increase of its production and the promotion of environmental awareness. Food waste from catering services in Hangzhou, China, was surveyed and characterized in this study. A questionnaire survey involving 632 units across the urban districts showed that 83.5% of the food waste was not properly treated. Daily food waste production from catering units was estimated to be 1184.5 tonnes. The ratio of volatile solid to total solid, easily biodegradable matter (including crude fat, crude protein and total starch) content in total solid and the ratio of total organic carbon to nitrogen varied in ranges of 90.1%-93.9%, 60.9%-72.1%, and 11.9-19.9, respectively. Based on the methane yield of 350 mL g VS(-1) in anaerobic batch tests, annual biogas energy of 1.0 × 10(9) MJ was estimated to be recovered from the food waste. Food waste from catering services was suggested to be an attractive clean energy source by anaerobic digestion.

[Clinical study of myocardial damage induced by neonatal jaundice in normal birth weight term infants].

OBJECTIVE: To clarify whether neonatal jaundice may cause myocardial damage to term infants with normal birth weight (BW). METHODS: Totally 178 term neonates admitted during March, 2004 to December, 2010 with normal BW were enrolled. Infants with antenatal or neonatal asphyxia, temperature abnormality, septicemia, antenatal viral infection, congenital dysmorphia, congenital heart disease, 21-trisomy, and polycythemia were excluded. There was no maternal complications during the pregnancy. Serum total bilirubin (TB), creatine kinase (CK), MB isoenzymes of creatine kinase (CK-MB), and cardiac troponin-I (cTnI) were measured. Patients with transcutaneous bilirubin level (TcB) ≥ 342 µmol/L (20 mg/dl) were in Group A (n = 32), and those with TcB below phototherapy level at matched time point were in Group B (n = 25). ECG, for correct Q-T intervals (QTc) and correct QT intervals dispersion (QTcd), and ECHO, for left ventricular ejection fraction (EF), the ratio of the peak velocity of early stage and advanced stage of diastolic phase at the mitral orifice (E/A), were applied to patients in Group A and B. SPSS 13.0 software was used for the data analysis. The coefficients of correlation among age in hours on admission (hr), TB, CK, CK-MB, CK-MB/CK, and cTnI were studied by multiple and partial correlation analysis. Data in Group A and B were compared by independent-samples Mann-Whitney U test (nonparametric method) or Student t-test. RESULTS: When the data were analyzed by multiple correlation, there were significant correlation between TB and cTnI, CK-MB, respectively (r = 0.212, -0.161, respectively, all P < 0.05). But, when the data were analyzed by partial correlation, there was no correlation between TB and cTnI, CK-MB, respectively (r' = 0.112, -0.112, respectively, all P > 0.05), negative correlation between hr and TB, cTnI, respectively (r' = -0.490, P = 0.000; r' = -0.162, P = 0.032). There was no significant difference in CK (Z = -1.384, P = 0.166), CK-MB (Z = -0.821, P = 0.412), cTnI (Z = -1.159, P = 0.246), QTc (t = 1.146, P = 0.257), QTcd (t = 1.342, P = 0.185), EF (t = 1.558, P = 0.125), E/A (t = -0.640, P = 0.525) between group A and B. There was significant difference in CK-MB/CK (Z = -3.187, P = 0.001) between group A and B with a lower value in group A [0.075 (0.032 - 0.102)] comparing to that in group B [0.160 (0.073 - 0.284)]. CONCLUSION: There is no sufficient evidence to support the hypothesis that neonatal jaundice may induce myocardial damage in normal birth weight term infants.