Bagasse-assisted bioremediation of ammonia from shrimp farm wastewater.

Development of new economically feasible ecofriendly products from agricultural wastes or byproducts for shrimp farm wastewater treatment is the objective of our continued research. Ammonia is a nitrogenous toxicant, which is commonly found in wastewater from shrimp farms. In the present study, we explored the possibility of the use of simply and inexpensively prepared bagasse products so that this abundant crop byproduct could be used to remove ammonia from shrimp farm wastewater. Bagasse, a natural highly fibrous lignocellulosic byproduct of sugarcane, was converted into five different products. Experimental results have shown that ammonia is efficiently removed from wastewater by four bagasse products with a dose of 1 to 6 g/L within 24 hours. The effect of bagasse products on other water quality parameters and growth kinetics of biofilm bacteria onto bagasse fiber have also been studied. Efficacies of products were compared by using statistical analysis. Products developed from bagasse are useful and economical.     

济南市道路扬尘排放因子估算及其影响因素研究

以济南城市道路为研究对象,采用美国环保署AP-42模型和方法,通过道路分类、优化布点、样品采集、实地观测和计算分析,获得道路粉尘负荷及四种类型道路扬尘的排放因子,探讨了排放因子的主要影响因素。结果表明,路面粉尘负荷随车流量增大而逐渐降低,城市城区路面粉尘负荷多小于城市外围路面,且外围道路路面粉尘负荷随时间和空间变化大;支路和次干道排放因子相对较小,快速路排放因子较高,主干道排放因子最高,其TSP、PM10、PM2.5排放因子分别高达25.239 3 g/VKT、4.731 1 g/VKT、0.597 2 g/VKT;排放因子随平均车重增加呈现逐渐增大趋势;同种类型道路排放因子均随道路粉尘负荷的增加而增加;次干道和快速路排放因子随车流量增大而减小。所获结论可为城市道路扬尘排放估算提供参考。     

兰州市典型企业VOCs排放特征及反应活性分析

基于兰州市大气VOCs排放清单,选取石化厂、乙烯厂、涂料厂3个典型企业采集VOCs样品,分析其无组织排放特征,并采用MIR（最大增量反应活性）法和LOH（·OH反应速率）法综合评价其化学反应活性,识别各企业的VOCs活性优势物种,同时探究不同企业特征VOCs比值.结果表明:不同排放源φ（VOCs）差异较大,范围为20.8×10-9~6 520.3×10-9.从VOCs物种构成上来看,涂料厂芳香烃占比最高,而石化厂、乙烯厂均以烷烃物种最为丰富,石化厂不同工艺VOCs物种构成略有差异.从活性上看,涂料厂VOCs活性最高,其LOH和OFP（臭氧生成潜势）分别为2 676.9 s-1和72 519.0×10-9,约为其他行业的18~1 000倍,间/对-二甲苯、乙苯、邻二甲苯等物种活性较大;其次为石化厂,其LOH和OFP分别为273.2 s-1和4 039.1×10-9,正戊烷、异戊烷、乙烯、丙烯等物种活性贡献率高,其中柴油工艺对石化厂VOCs活性贡献率最大;乙烯厂的OFP最低,其LOH和OFP分别为4.6 s-1和69.7×10-9,其VOCs活性主要来自乙烯、丙烯、正丁烯等烯烃物种.各工业源BTEX（苯、甲苯、乙苯及3种二甲苯异构体的合称）分布具有一定的差异,对于指示不同VOCs来源有一定的参考价值,但不同源比值的重叠性也表明并非全部VOCs来源可以通过特征物种比值来区分.研究显示,控制工业源特别是涂料与石化工业VOCs的排放有助于控制兰州市O₃的生成.      

微生物-生物促生剂协同修复河道底泥——促生剂投量对修复效果的影响

采用5个110L的模拟河道反应器,在投加菌剂的基础上（底泥稳定后向底泥和水中分别注射浓度为0.09%和0.03%的菌剂）,生物促生剂投量分别设计为0.08,0.09,0.10和0.11g/L,单独投加菌剂组作为空白实验.通过为期四十余天的实验研究微生物与促生剂协同作用时的修复效果.结果表明,促生剂投量为0.10g/L时,上覆水COD去除率69%高于其余各组;各协同修复组上覆水中NO₃^--N基本无积累,且促生剂投量为0.11g/L时NO₃^--N去除率最高,可达96%;40d内各组底泥TOC,TN含量变化不显著,延长反应时间至84d,各协同修复组底泥TOC,TN去除率均有明显提升.各协同修复组脲酶活性均波动下降,蛋白酶活性在15d左右时达到峰值,增幅可达106%~237%.通过高通量测序技术发现,43d时Desulfuromonas,Pseudomonas,Treponema_2,Blvii28_wastewater-sludge_group等主要功能菌群的相对丰度与空白实验组相比均增加,且促生剂投量为0.10g/L可使微生物群落向更适宜降解去除氮素及有机质的方向演替,有效改善底泥环境.协同修复对底泥,上覆水水质及微生物群落有良好改善效果,且促生剂投量为0.1g/L时整体修复情况更为理想.     

Enzyme-electrolytic degradation of dichloromethane: Efficiency, kinetics and mechanism

Enzymatic electrolysis cell(EEC) has advantages over microbial electrolysis cell(MEC) due to the needless of microbe inoculation and high-efficiency of enzymatic reaction. In this study, an EEC was first applied to achieve the effective degradation of halogenated organic pollutants and dichloromethane(CH_2Cl_2) was utilized as a model pollutant. The results indicate that the degradation efficiency of CH_2Cl_2 after 2 hr reaction in the EEC was almost100%, which was significantly higher than that with enzyme(51.1%) or current(19.0%). The current induced the continuous regeneration of reduced glutathione(GSH), thus CH_2Cl_2 was degraded under the catalysis of GSH-dependent dehalogenase through stepwise dechlorination, and successively formed monochloromethane(CH_3Cl) and methane(CH_4). The kinetic result shows that with a current of 15 mA, the maximum specific degradation rate of CH_2Cl_2(3.77 × 10~(-3) hr~(-1)) was increased by 5.7 times. The optimum condition for CH_2Cl_2 dechlorination was also obtained with pH, current and temperature of 7.0, 15 mA and 35°C,respectively. Importantly, this study helps to understand the behavior of enzymes and the fate of halogenated organic pollutants with EEC, providing a possible treatment technology for halogenated organic pollutants.     

云南不同类别基本农田土壤环境质量的时空差异

按照《农田土壤环境质量监测技术规范》（NY／T395--2000）,连续3年定点定位监测了云南亚热带干热河谷旱（缓）坡农耕地、中海拔旱（陡）坡农耕地和平坝区蔬菜地土壤环境质量。统计分析了监测结果的时间差异和空间差异。空间差异：旱（陡）坡农耕地〉旱（缓）玻农耕地〉平坝区蔬菜地;时间差异：旱（缓）坡农耕地〉平坝区蔬菜地〉旱（陡）坡农耕地。     

Ionic liquid-containing semipermeable membrane devices for monitoring the polycyclic aromatic hydrocarbons in water

Ionic liquid-containing semipermeable membrane devices (IL-SPMDs) were developed to monitor the polycyclic aromatic hydrocarbons in water. Uptake kinetics of naphthalene, 1-methylnaphthalene, phenanthrene, pyrene, chrysene by layflat low-density polyethylene tubing (15 cm x 2 cm) filled with 0.5 ml 1-butyl-3-methylimidazolium hexafluorophosphate ionic liquid were studied in a laboratory continuous-flow system for the duration of 16 days. The device concentration factors were in the range of 830-7800 for the studied PAHs. The kinetic parameters of IL/water partition coefficients, analytes uptake rate constants and sampling rates were estimated using mathematical models. These parameters were used in the field experiment to estimate the concentrations of the PAHs in Lanzhou section of Yellow River in China, with the result in comparison with that obtained by triolein-SPMD.     

振动加载下转换型密封电磁继电器的性能退化行为研究

目的研究航空用继电器的失效机理。方法通过对电磁继电器进行振动与工作载荷单独施加以及二者综合加载情况下的试验方法及性能退化行为研究,实时监测继电器内部触点间接触电阻等性能参数的变化趋势,并对不同条件下触点表面的微观形貌进行对比分析。结果发现相比较工作载荷单独施加而言,振动应力的加入使得继电器的寿命大幅度降低,并使得触点表面呈现"雪花"一般的形貌。结论振动环境导致了触点之间电弧的变化,以及触点表面接触压力、接触面积和接触超程等,并通过燃弧时间和超程时间的变化趋势对其进行了验证。     

纳米Al_2O_3和Cd联合暴露对铜锈环棱螺体内Cd的生物积累和抗氧化酶活性的影响

金属氧化物纳米颗粒的广泛应用导致它们大量地释放到水环境中,其独特的理化性质有可能改变水环境中其他共存污染物(如重金属)的生态毒性。为评价沉积物中纳米氧化铝(Al2O3-NPs)对重金属Cd生态毒性的影响,采用底栖生物慢性暴露研究了Al2O3-NPs存在条件下Cd在底栖动物铜锈环棱螺体内生物积累的变化和Cd对肝胰脏抗氧化防御系统关键成分超氧化物歧化酶(SOD)与脂质过氧化指标丙二醛(MDA)以及Ⅱ相反应的关键酶谷胱甘肽-S-转移酶(GST)的影响。结果表明,低Cd浓度(5μg·g-1)时,Al2O3-NPs对Cd生物积累没有影响;中、高Cd浓度(25、100μg·g-1)时,Al2O3-NPs显著促进Cd的生物积累,Al2O3-NPs对Cd的生物转运具有明显的携带效应。低Cd浓度时,无Al2O3-NPs处理组和Al2O3-NPs处理组的SOD活性与对照组相比均没有显著差异;中Cd浓度时,SOD活性显著升高,而高Cd浓度时,SOD活性显著下降,而且Al2O3-NPs处理组的SOD活性显著低于无Al2O3-NPs处理组,Al2O3-NPs的存在加重了Cd对肝胰脏细胞的氧化胁迫或损伤。高Cd浓度时,无Al2O3-NPs处理组和Al2O3-NPs处理组的MDA水平均显著升高,但Al2O3-NPs处理组的MDA水平显著低于无Al2O3-NPs处理组,进一步证明Al2O3-NPs对Cd氧化损伤的增强作用。中、高Cd浓度时,无Al2O3-NPs处理组和Al2O3-NPs处理组的GST活性均显著下降,但Al2O3-NPs处理组的GST活性均显著低于无Al2O3-NPs处理组,同样说明了Al2O3-NPs对Cd毒性的增强作用。本研究提供了在沉积物-底栖动物体系中Al2O3-NPs促进重金属生物积累的证据,而且Cd毒性的变化与肝胰脏中Cd的生物积累水平的变化基本一致,在中、高Cd浓度下,由于Al2O3-NPs的存在显著促进了Cd的生物积累,因而增强了Cd对铜锈环棱螺的生态毒性。