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981.
Yong-Jin Park Hiroshi Tsuno Taira Hidaka Ji-Hoon Cheon 《Journal of Material Cycles and Waste Management》2008,10(1):46-52
In this study, the effect of operational parameters, such as solids retention time (SRT), pH, and substrate total solids (TS)
concentration, on acid fermentation efficiency was investigated. From batch tests, it was shown that the appropriate pH range
for thermophilic acidogens was around 6–7 and that the optimum pH condition was 6. From the continuous experiment, pH and
SRT were shown to be the most important operational parameters for solubilization and organic acid production. In contrast,
TS concentration did not show any obvious effect on chromium chemical oxygen demand (CODcr) solubilization when TS was in
the range 3.5%–10%. The optimum operational conditions for thermophilic acid fermentation were an SRT of 2 days and a pH of
6.
This research was carried as a part of the CREST project of Japan Science and Technology Agency. 相似文献
982.
983.
曹舟艳 《环境监测管理与技术》2014,26(5):64-66
采用相对电导率差(CPD)法、电导率-pH不等式法对某监测站大气降水的实测电导率和pH值等数据进行质量分析。根据分析结果认为可用CPD法来检验、评估降水中各种离子成分的分析是否完整、准确,用电导率-pH不等式法来检验电导率和pH值的测定值是否存在明显的误差。 相似文献
984.
Control of odours should be considered to be a fundamental issue in order to site, design and manage sanitary landfills. With regard to construction and demolition (C&;D) debris, landfilling was the mainly adopted solution in many European Countries; in particular, gypsum drywalls can produce high concentrations of hydrogen sulphide (H2S) in landfill gas ranging from 7 ppm to 100 ppm. In some cases also dangerous concentrations until to 12,000 ppm were detected. In this paper H2S removal efficiency in a lab-scale vertical packed scrubber was investigated. Hydrogen sulphide abatement was evaluated for inlet H2S concentrations of 1000–100–10 ppm, adjusting scrubbing liquid pH in the range 9–12.5 by means of caustic soda (NaOH 2N solution). Moreover, best operating conditions for the system were defined as well as H2S abatement along the tower and liquid recirculation effectiveness in case of inlet H2S concentration of 10 ppm (typical odour concentration). Results showed that pH of 11.5 in scrubbing liquid could be considered the best value for removal of different inlet H2S concentrations, also taking into account parasitical consumption of NaOH due to CO2 absorption. Moreover, in case of continuous working of the system at H2S concentration of 10 ppm, strong removal efficiency was already obtained with a packed bed height of about 70 cm. Significant performances were ensured after 1 h of constant activity, consuming about 3 ml of soda per cubic meter of polluted air. Subsequently liquid blowdown was necessary. 相似文献
985.
Shen Neng 《中国人口.资源与环境(英文版)》2011,9(3):58-65
In this paper,the author uses super-efficiency DEA model to measure the national and regional energy efficiency in China;using spatial econometric model and from the perspective of geo-spatial spillover,the author interprets the spatial characteristics of energy efficiency and extracts the main factors that influence the regional energy efficiency.The analysis results show that:(1) the national and regional energy efficiency is consistent with inverted U-shaped curve,and the nationwide energy efficiency gap is increasing;(2) energy efficiency has the obvious effect of the spatial external effect,and when the government makes energy saving strategies,inter-regional energy cooperation and the proliferation of advanced production technology should be given more priority;(3) energy efficiency has significant negative correlation with government intervention,industrial structure,ownership structure,the energy consumption structure,and resource endowments,and has positive correlation with the degree of opening-up and energy price. 相似文献
986.
以柴油为污染物,通过一维砂柱实验模拟油污土壤中柴油去除过程,从油水界面张力(IFT)角度分析溶液pH、淋滤速度和表面活性物质对除油效果的影响。结果表明,延长油水接触时间、升高或降低蒸馏水pH值均使油水界面张力下降,低淋滤速度下单位孔隙体积水中石油浓度较大,而水溶液pH的变化对除油效果影响不明显。十二烷基硫酸钠(SDS)和乙醇使油水界面张力显著下降,因此表面活性物质的除油效率明显高于蒸馏水,乙醇溶液的除油效率随着体积浓度的增加而升高。从石油释放动力学方程计算的柴油累积释放量看,50%乙醇除油效率最高,8 mmol/L SDS溶液次之,在淋洗初期柴油去除效果最为明显,而在中期和后期除油率增加幅度逐渐减小。 相似文献
987.
Myung-Chan Ahn Thomas M. Holsen Young-Ji Han 《Environmental pollution (Barking, Essex : 1987)》2010,158(2):347-355
The effects of various factors including turbidity, pH, DOC, temperature, and solar radiation on the concentrations of total mercury (TM) and dissolved gaseous mercury (DGM) were investigated in an artificial reservoir in Korea. Episodic total mercury accumulation events occurred during the rainy season as turbidity increased, indicating that the TM concentration was not controlled by direct atmospheric deposition. The DGM concentration in surface water ranged from 3.6 to 160 pg/L, having a maximum in summer and minimum in winter. While in most previous studies DGM was controlled primarily by a photo-reduction process, DGM concentrations tracked the amount of solar radiation only in winter when the water temperature was fairly low in this study. During the other seasons microbial transformation seemed to play an important role in reducing Hg(II) to Hg(0). DGM increased as dissolved organic carbon (DOC) concentration increased (p-value < 0.01) while it increased with a decrease of pH (p-value < 0.01). 相似文献
988.
Carly J. Stevens Cecilia Duprè Cassandre Gaudnik Albert Bleeker Didier Alard David Fowler J. Owen Mountford Per Arild Aarrestad Nancy B. Dise 《Environmental pollution (Barking, Essex : 1987)》2010,158(9):2940-2945
Evidence from an international survey in the Atlantic biogeographic region of Europe indicates that chronic nitrogen deposition is reducing plant species richness in acid grasslands. Across the deposition gradient in this region (2-44 kg N ha−1 yr−1) species richness showed a curvilinear response, with greatest reductions in species richness when deposition increased from low levels. This has important implications for conservation policies, suggesting that to protect the most sensitive grasslands resources should be focussed where deposition is currently low. Soil pH is also an important driver of species richness indicating that the acidifying effect of nitrogen deposition may be contributing to species richness reductions. The results of this survey suggest that the impacts of nitrogen deposition can be observed over a large geographical range. 相似文献
989.
S.P. McGrath C. Micó F.J. Zhao 《Environmental pollution (Barking, Essex : 1987)》2010,158(10):3095-3102
The effect of soil properties on the toxicity of molybdenum (Mo) to four plant species was investigated. Soil organic carbon or ammonium-oxalate extractable Fe oxides were found to be the best predictors of the 50% effective dose (ED50) of Mo in different soils, explaining > 65% of the variance in ED50 for four species except for ryegrass (26-38%). Molybdenum concentrations in soil solution and consequently plant uptake were increased when soil pH was artificially raised because sorption of Mo to amorphous oxides is greatly reduced at high pH. The addition of sulphate significantly decreased Mo uptake by oilseed rape. For risk assessment, we suggest that Mo toxicity values for plants should be normalised using soil amorphous iron oxide concentrations. 相似文献
990.