[Enhanced Membrane Anti-fouling Ability of Anaerobic Membrane Bioreactor Equipped with Bio-electrochemical System Using Nano-zero-valent Iron and Its Regulation Mechanism].

Membrane fouling is the biggest challenge of membrane bioreactor industrialization. In this study, a bio-electrochemical system (BES)-anaerobic membrane bioreactor (AnMBR) system was constructed, and the effect of nano-zero-valent iron (nZVI) on membrane anti-fouling ability and methane production was investigated. The results showed that the BES-AnMBR system was stable and the chemical oxygen demand (COD) removal rate was maintained at approximately 95%. The optimum condition was observed to be nZVI 0.1 g·g-1(VS). Under this condition, transmembrane pressure (TMP) was reduced by 28.1%, the membrane flux had a slight improvement, and methane production was up to 81.3 mL·g-1(CODremoved). This was 12.1% higher than that of the control. In addition, a further analysis of extracellular polymeric substances (EPS) fraction and membrane resistance showed that nZVI enhanced EPS decomposition, promoted the formation of an iron-rich layer of inorganic and organic matters on the membrane surface, and changed the distribution of organics and inorganics, thereby significantly alleviating membrane fouling. This study will enrich basic theory of conventional AnMBR and provide a new solution for efficient sludge treatment and resource utilization.

[Performance of Anaerobic Membrane Bioreactors for the Co-digestion of Sewage Sludge and Food Waste].

A laboratory-scale anaerobic membrane bioreactor (AnMBR) was used for the co-digestion of sewage sludge and food waste to investigate its organic matter removal characteristics, biogas production performance, and microbial community composition. The results showed that the degradation rate of volatile solids (VS) increased from 17.5% for a single digestion to 40% for the total digestion, and that the COD removal was 95.3% when the organic loading rate (OLR) was stabilized at 0.59-0.64 kg·(m3·d)-1. The solids content of the digested sludge increased by a factor of 3.9. The final CH4 content was 60% and the CH4 yield was 78.7 mL·g-1 of CODadded. The transmembrane pressure (TMP) and average flux were maintained at between -3.1 and -2.7 kPa and 0.106 L·(m2·h)-1, respectively, and membrane fouling was not serious. According to an analysis of the microbial diversity using 16S rRNA, the anaerobic bacterium in the AnMBR were mainly phylum Proteobacteria, Bacteroidetes, and Cloacimonetes, and the dominant methanogens included the Methanobacterium family, Methanosaeta genus, and Methanolinea genus. This study provides a strong theoretical basis for research into the stability and performance of AnMBRs for the co-treatment of sludge and other high-solid waste streams, and provided an effective solution for biomass resource utilization and the energy crisis.

[Development and Output Characteristics of 785 nm Portable Grating-Coupled External Cavity Tunable Semiconductor Laser].

Aiming at the miniaturization requirement of shifted excitation Raman spectroscopy test system, a portable grating-coupled external cavity (EC) tunable semiconductor laser in Littrow configuration is designed and fabricated with a commercial 785 nm high-power laser diode as the gain device. By using a new wavelength tuning method, aiming to change the position of gain device relative to the collimating lens in the horizontal direction, a miniaturized device with the size of 140 mm×65 mm×50 mm is designed. Compared to the traditional wavelength tuning method which is to change the light incident angle by rotating the diffraction grating, this new tuning method reduces the translational distance of semiconductor gain device effectively, thus it is conductive to the fast and broad wavelength tuning of portable EC laser. The experimental results show that the EC laser has a wide wavelength tuning range. Under any injection current from 340 to 900 mA, a wavelength tuning range of more than 10 nm can be realized. Especially at 900 mA, good performance including a 11.67 nm-wavelength tuning range from 779.40 to 791.07 nm, a less than 0.2 nm-spectral linewidth, an up to 280 mW-output power, and a more than 25 dB-amplified spontaneous emission suppression ratio is presented, which fully meets the basic testing requirements of shifted excitation Raman spectroscopy. Moreover, 1.35 nm-electric wavelength tuning range is achieved by applying a mini-piezoelectric actuator. This indicates that the home-made 785 nm portable grating-coupled EC tunable semiconductor laser is suitable as the light source of portable shifted excitation Raman spectroscopy testing system to eliminate the fluorescence background of Raman spectrum.

Innovative combination of electrolysis and Fe(II)-activated persulfate oxidation for improving the dewaterability of waste activated sludge.

The feasibility of electrolysis integrated with Fe(II)-activated persulfate (S2O8(2-)) oxidation to improve waste activated sludge (WAS) dewaterability was evaluated. The physicochemical properties (sludge volume (SV), total suspended solids (TSS) and volatile suspended solids (VSS)) and extracellular polymeric substances (EPS), including slime EPS, loosely bound EPS (LB-EPS) and tightly bound EPS (TB-EPS) were characterized to identify their exact roles in sludge dewatering. While dewaterability negatively corresponded to LB-EPS, TB-EPS, protein (PN) and polysaccharide (PS) in LB-EPS and TB-EPS, it was independent of SV, TSS, VSS, slime EPS and PN/PS. Further study through scanning electron microscope (SEM) verified the entrapment of bacterial cells by TB-EPS, protecting them against electrolysis disruption. Comparatively, electrolysis integrated with S2O8(2-)/Fe(II) oxidation was able to effectively disrupt the protective barrier and crack the entrapped cells, releasing the water inside EPS and cells. Therefore, the destruction of both TB-EPS and cells is the fundamental reason for the enhanced dewaterability.

Molecular cloning, expression pattern, and putative cis-acting elements of a 4-coumarate: CoA ligase gene in bamboo (Neosinocalamus affinis)

Background: 4-coumarate:CoA ligase (4CL) plays an important role at the divergence point from general phenylpropanoid metabolism to several branch pathways. Although 4CL sin higher plants have been extensively studied, little has known about the 4CL gene of bamboo. Results: In current study, a Na4CL gene putative encoding 4-coumarate:CoA ligase (4CL) and its 5’-flanking region were isolated from bamboo (Neosinocalamus affinis) by RACE-PCR and genomic DNA walker, respectively. Na4CL encodes a predicted protein of 557 amino acids, with conserved motifs of adenylate-forming enzymes. Phylogenetic analysis showed that Na4CL shared 62~85 percent identity with other known plant 4CLs, and cluster closely with some known 4CLs in monocots. Sequence analysis revealed conserved cis-acting elements (Box A and AC-II element) present in the Na4CL promoter. Additionally, a Na4CL RNAi construct was transformed into tobacco. Transgenic tobaccos displayed significant down-expression of endogenesis 4CL and reduced lignin contents. Conclusion: These results contribute to the knowledge of the presence of Na4CL gene and its possible role in phenylpropanoid metabolism.

[Effects of drought on output of Gastrodia elata].

The experiments of water supply showed out drought can decrease water potencial and the output of Gastrodia elata. Those negative effects might be conpensated by hybridi combination, and its output should be increased.