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811.
好氧-厌氧污泥耦合白腐真菌单元对焦化废水的处理 总被引:1,自引:0,他引:1
白腐真菌因能分泌胞外木质素降解酶降解难降解有机污染物,而在难降解有机废水处理中具有巨大应用潜力.其研究常采用白腐真菌直接处理废水,很少关注常规生物法耦合白腐真菌的处理方式.基于此,分别采用白腐真菌和好氧-厌氧污泥耦合Phanerochaete Chrysosporium处理焦化废水以考察后者的可行性.在好氧-厌氧污泥耦合P.chrysosporium的处理中,仅采用3 d的处理时间,好氧-厌氧污泥可将6097 mg·L~(-1)的COD和351 mg·L~(-1)的氨氮分别降至1634~1684 mg·L~(-1)和102~117 mg·L~(-1);进而固定化P.chrysosporium将COD和氨氮再次分别降至1322~1372 mg·L~(-1)和16~62 mg·L~(-1).最终COD和氨氮的去除率分别达77%~78%和82%~95%,这表明:好氧-厌氧污泥耦合P.chrysosporium处理焦化废水可在更短的处理周期完成比直接采用白腐真菌处理更好的处理效果,此思路合理可行. 相似文献
812.
Ming-Shean Chou Wen-Hsi Cheng Wei-Shen Lee 《Journal of the Air & Waste Management Association (1995)》2013,63(12):2112-2119
ABSTRACT A pilot apparatus of a regenerative catalytic oxidizer (RCO) equipped with two electrical heaters and two 20-cm i.d. × 200-cm height regenerative beds was used to treat methyl ethyl ketone (MEK) and toluene, respectively, in an airstream. The regenerative beds were packed with gravel (approximate particle size 1.25 cm, specific area 205 m2/m3, and specific heat capacity 840 J/kg °C) as a solid regenerative material and K-type thermal couples for measuring solid and gas temperatures, respectively. The catalyst bed temperature was kept around 400 °C and the gas superficial velocity was operated at 0.234 m/sec. This investigation measured and analyzed distributions of solid and gas temperatures with operating time and variations of volatile organic compound (VOC) concentrations in the regenerative beds. The overall VOC removal efficiency exceeded 98% for MEK and 95% for toluene. Degradation of VOCs will exist for MEK on the surface of solid material (gravel) in the temperature range of 330-400 °C, but toluene does not exhibit this phenomenon. 相似文献
813.
按30 m的梯度将海拔2 880~3 360 m分为16个采样点,在同一海拔高度按照"Z"字形取样,共取5个点,对16个采样点的土样混匀后以根残体分离法在镰刀菌选择性培养基上进行分离,对分离得到的镰刀菌菌落进行纯化和单孢分离后,以形态学为基础,参照Nelson分类系统进行鉴定.结果表明:在分离到的212个镰刀菌菌株中,有5个菌株为三线镰孢(Fusarium tricinctum).随机选取2株三线镰孢菌株进行β-tubulin基因序列分析,将PCR产物回收测序后在Genbank上比对,菌株TZh-4-3-7和TZh-11-5-2与GenBank上登记的6个新西兰菌株的亲缘关系最近,同源性达96%.利用DNAStar软件绘制其系统发育树状图,结果显示,菌株TZh-4-3-7和TZh-11-5-2与以上6个F.tricinctum菌株均位于系统发育树的同一分支,聚为一类.本研究采用的β-tubulin基因序列分析结果验证了利用形态学鉴定镰刀菌的准确性;将β-tubulin基因序列分析应用于三线镰孢的鉴定中,拓宽了鉴定途径,提高了鉴定的准确性;并了解了三线镰孢在天祝高寒草原不同海拔高度的分布,丰富了我国草原镰刀菌资源库,为进一步探讨镰刀菌与草原退化的关系奠定了基础. 相似文献
814.
Lee Wei-Hao Hsu Chih-Wei Ding Yung-Chin Cheng Ta-Wui 《Journal of Material Cycles and Waste Management》2018,20(1):375-385
Journal of Material Cycles and Waste Management - The objective of this study is to recover SiC from silicon wafer cutting slurry using physical separation and acid/alkali purification processes.... 相似文献
815.
基于热重分析试验和固定床热解试验,研究了升温速率和温度对高矿物质含量的炼焦煤尾煤热解特性的影响.尾煤热解过程可分为室温~400℃、400~600℃及600~950℃3个阶段.采用CoatsRedfern积分法拟合计算了尾煤热解的动力学参数,表明炼焦煤尾煤热解反应过程可以用3个二级反应进行描述,其热解反应活化能介于22.6~66.2 kJ/mol.固定床试验结果表明,温度对尾煤挥发分的析出有重要影响,高温有利于尾煤中高分子有机组成裂解和挥发分析出,最终决定了尾煤的热解反应进程.600℃前气体缓慢析出,之后,随温度升高,气体产量和热值增加显著,H2和CO随温度升高而增加,CH4和CO2先增加后减少.H2在600℃前析出缓慢,600℃后大量析出,在900℃左右达到最大析出量,贯穿整个反应过程.CO在900℃左右达到最大析出量;CH4和CO2在800℃左右达到最大值,之后开始下降.终温950℃时,30 g尾煤热解产气4 300 mL,H2产量1 722mL;焦煤产气7 950 mL,H2产量2 716 mL.尾煤热解富H2体产量达焦煤热解气产量的54%,具有较高的再利用价值. 相似文献
816.
Visual cues are important navigational tools for many solitary foraging insects. In addition to information provided by path
integration, desert ants learn and use visual cues for homing back to their nest. In this study, we compared the visually
based learning of two desert ant species: the North African Cataglyphis fortis and the Australian Melophorus bagoti, each of which lives in ecologically similar but visually different environments. In our experiment, ants’ choice performance
was measured by training foragers in a channel system. We used a decision box with two visual stimuli during their homebound
trips, with one of the stimuli always being the correct one that provided thoroughfare. To determine any habitat effects on
learning, we examined intraspecific comparisons in C. fortis with different nest surroundings. The intraspecific comparison in C. fortis revealed no differences in learning the task. In general, C. fortis showed little learning in our task and the results were similar for ants from barren and cluttered environments. Overall,
M. bagoti learned the task faster and had a higher level of accuracy than C. fortis. One explanation for this species-specific difference could be that the cluttered habitat of M. bagoti favours the evolution of visual associative learning more so than the plain habitat of C. fortis. 相似文献
817.
Morton Corn Robert T. Cheng 《Journal of the Air & Waste Management Association (1995)》2013,63(11):870-875
A laboratory study was conducted of the heterogeneous catalysis of sulfur dioxide at ppm concentrations in air by insoluble particles of CaCO2, V2O5, Fe203, flyash from a coal-burning power plant, MnCO2, activated carbon, and suspended particulate matter from urban air. The investigalion was performed by utilizing a new technique for aerosol stabilization which consists of depositing the aerosol on Teflon beads in a fluidized bed. The Teflon beads with deposited aerosol particles were then packed into a flow reactor. Progress of the chemical reaction of SO2 with deposited particles was continuously monitored by determining the SO2 concentrations in the reactor effluent with a microcoulometer. In this investigation, CaCOg, V2O5, and flyash were essentially inert to SO2 at room temperature. Fe2O3, activated carbon, MnO2, and suspended particulate matter from urban air sorbed SO2 from air streams with up to 14.4 ppm SO2 in air. Evidence is presented which suggests that a substantial part of the sorbed SO2 was physically adsorbed. Bioassay procedures which utilize pulmonary flow resistance changes in guinea pigs to monitor response to inhaled SO2-aerosol mixtures in air have indicated the weak or non-potentiating capacity of insoluble aerosols as contrasted to soluble aerosols. Potentiating response of an aerosol appears to be strongly associated with reaction of SO2 in a water droplet containing aerosol ions and not with physically adsorbed SO2 on an insoluble aerosol. 相似文献
818.
S. Mackinson G. Daskalov J.J. Heymans S. Neira H. Arancibia M. Zetina-Rejón H. Jiang H.Q. Cheng M. Coll F. Arreguin-Sanchez K. Keeble L. Shannon 《Ecological modelling》2009
Fishing mortality and primary production (or proxy for) were used to drive the dynamics of fish assemblages in 9 trophodynamic models of contrasting marine ecosystems. Historical trends in abundance were reconstructed by fitting model predictions to observations from stock assessments and fisheries independent survey data. The model fitting exercise derives values for otherwise unknown parameters that specify the relative strength of trophic interactions and, in some instances, a time series anomaly for changes in primary production. We measured how much better or worse were model predictions when bottom-up forcing by primary production were added to top-down forcing by fishing. Searching for cross system patterns, the relative contribution of fishing and changes in primary production, mediated through trophic interactions, are evaluated for the ecosystems as a whole and for selected similar species in different ecosystems. The analysis provides a simple qualitative way to explain which forcing factors have most influence on modeled dynamics. Both fishing and primary production forcing were required to obtain the best model fits to data. Fishing effects more strongly influenced 6 of 9 of the ecosystems, but primary production was more often found to be the main factor influencing the selected pelagic and demersal fish stock trends. Examination of sensitivity to ecological and model parameters suggests that the results are the product of complex food-web interactions rather than simple deterministic responses of the models. 相似文献
819.
Impacts of Dung Combustion on the Carbon Cycle of Alpine Grassland of the North Tibetan Plateau 总被引:2,自引:0,他引:2
Zengrang Xu Shengkui Cheng Lin Zhen Ying Pan Xianzhou Zhang Junxi Wu Xiuping Zou G. C. Dhruba Bijaya 《Environmental management》2013,52(2):441-449
Alpine grassland of Tibet is a frangible ecosystem in terms of carbon (C) emission. Yak dung is an important resident energy with about 80 % of yak dung combusted for energy in the north Tibetan plateau. This paper investigated the impact of dung combustion on the C cycle of the alpine grassland ecosystem in north Tibet, China. During the growing season of 2011, from a field survey and household questionnaires, the main impacts of dung collection for fuel on the C cycle of the ecosystem were identified. (1) The C sequestration and storage capacity, including the dung-derived C stored in soil and C captured by vegetation, decreased. The net primary production decreased remarkably because of the reduction of dung returned to soil. (2) In a given period, more C was emitted to the atmosphere in the dung combustion situation than that in the dung returned to soil situation. (3) The energy grazing alpine meadow ecosystem changed into a net C source, and the net biome production of the ecosystem dropped to ?15.18 g C/m2 year in the dung combustion situation, 42.95 g C/m2 year less than that in the dung returned situation. To reduce the CO2 emission derived from dung use, the proportion of dung combustion should be reduced and alternative renewable energy such as solar, wind, or hydro energy should be advocated, which is suitable for, and accessible to, the north Tibetan plateau. 相似文献
820.
Yongyang Fu Feifei Li Ting Xu Sanjuan Cai Weiyue Chu Han Qiu Sha Sha Guangyu Cheng Qinsong Xu 《Environmental science and pollution research international》2014,21(4):2935-2942
Bioaccumulation, subcellular distribution, and acute toxicity of yttrium (Y) were evaluated in Nymphoides peltata. The effects of Y concentrations of 1–5 mg L?1 applied for 4 days were assessed by measuring changes in photosynthetic pigments, nutrient contents, enzymatic and non-enzymatic antioxidants, and ultrastructure. The accumulation of Y in subcellular fractions decreased in the order of cell wall > organelle > soluble fraction. Much more Y was located in cellulose and pectin than in other biomacromolecules. The content of some mineral elements (Mg, Ca, Fe, Mn, and Mo) increased in N. peltata, but there was an opposite effect for P and K. Meanwhile, ascorbate, and catalase activity decreased significantly for all Y concentrations. In contrast, peroxidase activity was induced, while initial rises in superoxide dismutase activity and glutathione content were followed by subsequent declines. Morphological symptoms of senescence, such as chlorosis and damage to chloroplasts and mitochondria, were observed even at the lowest Y concentration. Pigment content decreased as the Y concentration rose and the calculated EC50 and MPC of Y for N. peltata were 2 and 0.2 mg L?1 after 4 days of exposure, respectively. The results showed that exogenous Y was highly available in water and that its high concentration in water bodies might produce harmful effects on aquatic organisms. N. peltata is proposed as a biomonitor for the assessment of metal pollution in aquatic ecosystems. 相似文献