低温微生物低温适应性的机制及其应用前景

低温微生物由于长期生活在寒冷的环境中,在自然选择的作用下形成一套独特的与低温环境相适应的细胞结构和分子机制。从细胞结构、组成的变化,以及分子水平等角度阐述了近年来国内外有关低温微生物低温适应性机制的研究进展;探讨了低温微生物在环境净化、食品化工和医药等行业中的广泛应用前景。     

丹东市大气污染特征及原因

丹东市大气污染具有鲜明的季节特征,采暖季市区内SO2污染较重,沙尘天气和大风天气时PM10测值较大,尘污染较重,除夕燃放鞭炮造成SO2和PM10严重污染;燃煤锅炉是造成SO2污染的主要来源;逆温、静风等不利气象条件是大气污染的决定性因子。     

SBR处理制药废水影响因素的研究

结合工程实际采用水解酸化-SBR工艺处理制药废水,处理水量为2 000 m3/d。SBR对CODcr的处理率稳定在92.2%～95.8%间,平均为94.23%,对氨氮的去除率在82.7%～97.6%,平均去除率达到90.73%。水解酸化-SBR稳定运行后,系统出水各项指标均达到国家《污水综合排放标准》(8978-1996)二级排放标准。运行结果表明,SBR运行最佳参数为:曝气时间8小时,污泥负荷控制0.23～0.28(kg CODcr/kg MLSS.d),温度26℃～30℃。该工艺用于处理高浓度制药废水效果稳定,耐冲击负荷高。     

Synthesis and Characterization of Biodegradable Starch-Polyacrylamide Graft Copolymers Using Starches with Different Microstructures

The effects of starch structures, in particular amylose content, on grafting reactions were investigated using thermal gravimetric analysis (TGA), nuclear magnetic resonance, X-ray diffraction (XRD). As a model system, corn starches with different amylose contents (0, 26, 50 and 80 %) were grafted onto acrylamide to produce superabsorbent polymers (SAPs). The weight loss measured by TGA at different temperature was used to analyze the grafting ratio in quantity. In general, the grafting ratio increased (about 10 %) with increasing starch amylose content, and graft chain segment lengths were much lower for the amylopectin-rich (waxy) starch. The high molecular weight and branched structure of the amylopectin reduced the mobility of the polymer chains and increased viscosity, which resulted in resistance to chain growth. The water absorption capability was increased with increasing amylose content for the starch-based SAPs. XRD detection showed that the crystalline structure of all starches was destroyed after grafting reactions. The thermal stability of the polyacrylamide grafted onto the starches increased by about 10 °C, which could be explained by the strong bonding between the grafted polymer chains and the starch matrices.     

Pilot-scale anaerobic co-digestion of municipal biomass waste and waste activated sludge in China: Effect of organic loading rate

The effects of organic loading rate on the performance and stability of anaerobic co-digestion of municipal biomass waste (MBW) and waste activated sludge (WAS) were investigated on a pilot-scale reactor. The results showed that stable operation was achieved with organic loading rates (OLR) of 1.2–8.0 kg volatile solid (VS) (m³ d)^?1, with VS reduction rates of 61.7–69.9%, and volumetric biogas production of 0.89–5.28 m³ (m³ d)^?1. A maximum methane production rate of 2.94 m³ (m³ d)^?1 was achieved at OLR of 8.0 kg VS (m³ d)^?1 and hydraulic retention time of 15 days. With increasing OLRs, the anaerobic reactor showed a decrease in VS removal rate, average pH value and methane concentration, and a increase of volatile fatty acid concentration. By monitoring the biogas production rate (BPR), the anaerobic digestion system has a higher acidification risk under an OLR of 8.0 kg VS (m³ d)^?1. This result remarks the possibility of relating bioreactor performance with BPR in order to better understand and monitor anaerobic digestion process.     

Secondary organic aerosol formation from straw burning using an oxidation flow reactor

Herein, we use an oxidation flow reactor, Gothenburg: Potential Aerosol Mass (Go: PAM) reactor, to investigate the secondary organic aerosol (SOA) formation from wheat straw burning. Biomass burning emissions are exposed to high concentrations of hydroxyl radicals (OH) to simulate processes equivalent to atmospheric oxidation of 0-2.55 days. Primary volatile organic compounds (VOCs) were investigated, and particles were measured before and after the Go: PAM reactor. The influence of water content (i.e. 5% and 11%) in wheat straw was also explored. Two burning stages, the flaming stage, and non-flaming stages, were identified. Primary particle emission factors (EFs) at a water content of 11% (∼3.89 g/kg-fuel) are significantly higher than those at a water content of 5% (∼2.26 g/kg-fuel) during the flaming stage. However, the water content showed no significant influence at the non-flaming stage. EFs of aromatics at a non-flaming stage (321.8±46.2 mg/kg-fuel) are larger than that at a flaming stage (130.9±37.1 mg/kg-fuel). The OA enhancement ratios increased with the increase in OH exposure at first and decreased with the additional increment of OH exposure. The maximum OA enhancement ratio is ∼12 during the non-flaming stages, which is much higher than ∼ 1.7 during the flaming stages. The mass spectrum of the primary wheat burning organic aerosols closely resembles that of resolved biomass burning organic aerosols (BBOA) based on measurements in ambient air. Our results show that large gap (∼60%-90%) still remains to estimate biomass burning SOA if only the oxidation of VOCs were included.     

PVC-based composite material containing recycled non-metallic printed circuit board (PCB) powders

The study is directed to the use of non-metallic powders obtained from comminuted recycled paper-based printed circuit boards (PCBs) as an additive to polyvinyl chloride (PVC) substrate. The physical properties of the non-metallic PCB (NMPCB) powders were measured, and the morphological, mechanical and thermal properties of the NMPCB/PVC composite material were investigated. The results show that recycled NMPCB powders, when added below a threshold, tended to increase the tensile strength and bending strength of PVC. When 20 wt% NMPCB powders (relative to the substrate PVC) of an average diameter of 0.08 mm were added, the composite tensile strength and bending strength reached 22.6 MPa and 39.83 MPa, respectively, representing 107.2% and 123.1% improvement over pure PVC. The elongation at break of the composite material reached 151.94% of that of pure PVC, while the Vicat softening temperature of the composite material did not increase significantly compared to the pure PVC. The above results suggest that paper-based NMPCB powders, when used at appropriate amounts, can be effective for toughening PVC. Thus, this study suggests a new route for reusing paper-based NMPCB, which may have a significant beneficial environmental impact.     

渤海西岸微量元素表生地球化学特征

本文讨论了有关:1)痕量元素地球化学背景值;2)痕量元素地球化学表征;及3)我国某些地区若干痕量元素的背景值。     

生活垃圾固结技术及其安全性研究

针对生活垃圾产生量逐年增多的趋势，采用新型固化技术对陈腐生活垃圾进行固结，并对其固结效果和安全性进行研究。研究结果表明：本固结技术可使生活垃圾固结体28d强度达38MPa以上，其耐久性能诸如抗冻性能、耐水性能、抗干湿循环能力和抗硫酸盐侵蚀性能较为优越。并且其固结体重金属溶出量亦满足国家标准，即生活垃圾中的重金属离子得到有效的束缚和稳定固化。     

高效藻类塘氮磷去除机理的研究进展

首先介绍了高效藻类塘的发展历史和特点，其次简述了高效藻类塘的生物特性和物理化学变化规律，并重点论述了高效藻类塘的氮磷去除机理及其影响因素，最后对高效藻类塘在控制非点源污染中的应用前景进行展望。