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71.
Yang JF Ying GG Liu S Zhou LJ Zhao JL Tao R Peng PA 《Journal of environmental science and health. Part. B》2012,47(4):288-295
This paper investigated the degradation kinetics of norfloxacin in a soil, and its effects on soil respiration and nitrogen transformation under different conditions. Compared to the sterile control, the degradation rates of norfloxacin in the non-sterile soil were greatly enhanced, suggesting that microorganisms played a major role in the degradation. Accelerated degradation for norfloxacin in the soil was observed with decreasing concentrations (30 mg/kg to 5 mg/kg) with its half-life decreasing from 62 days to 31 days. Amending swine manure into the soil and increasing the soil moisture level enhanced the biological degradation of norfloxacin. No obvious inhibition of norfloxacin on soil respiration was observed in the soil, while only slight effect on nitrogen transformation was found. The results suggested that norfloxacin at the reported environmental concentrations (<100 mg/kg) would have little effect on microbial activity and functions in the soils. 相似文献
72.
厌氧-局部循环供氧生物膜技术处理农村污水 总被引:1,自引:0,他引:1
通过模拟农村生活污水水质和间歇进水特点,利用“厌氧-局部循环供氧生物膜”技术,研究该工艺对有机物、氮、磷的去除效果.厌氧池和局部循环供氧池有效容积比为1∶1.6,曝气装置位于局部循环供氧池中间底部,环形导流板将局部循环供氧池分隔成中间好氧区和四周缺氧区,斜管沉淀池前置到厌氧池与局部循环供氧池之间,出水端设置循环水池.装置连续稳定运行12个月,平均进水量为140 L/d,生物反应区HRT为1.3d.监测结果表明,出水COD、BOD、NH3-N、TN和TP平均浓度分别在40.31、3.38、2.69、11.98和0.75 mg/L,达到了国家城镇污水处理厂污染物排放指标(GB-18918-2002)中的一级排放标准.研究表明,厌氧-局部循环供氧技术是一种适合农村分散污水处理的新工艺,可有效减轻农业面源污染. 相似文献
73.
Influences of adding easily degradable organic waste on the minimization and humification of organic matter during straw composting 总被引:2,自引:0,他引:2
Yi N. Shan Jin H. Chen Lei Wang Fan Li Xiao H. Fu Yi Q. Le 《Journal of environmental science and health. Part. B》2013,48(5):384-392
To find a better composting process with low greenhouse gas emission and high humus production, the effect of adding kitchen waste on reduction and humification of organic matter during straw composting was studied. Three processes were compared, consisting of different ratios of straw and kitchen waste (1:2, 1:1, and 2:1). At four time points over a 62-d incubation, the reduction and humification of compost was evaluated by measuring the total mass, carbon content, and humic material content of the compost. Treatment 1 (straw/kitchen waste ratio of 1:2) reduced the total mass of compost the most. Treatment 2 (straw/kitchen waste ratio of 1:1) reduced the total carbon content the most, reflecting the highest emission of greenhouse gas. Treatment 3 produced the most humic acid material and released the lowest amount of carbon. Hence, from the point of view of reducing greenhouse gas emissions and increasing stable organic matter such as humus and humic acid during composting, treatment #3 was optimal. The three treatments resulted in significant differences in microbial biomass and enzyme activity during composting. The highest amount of active microbial biomass was associated with the largest reduction in compost mass (treatment 1). Higher proportions of straw (treatments 2 and 3), which contains more lignin, were associated with greater β-glycosidase activity, which may generate more humus that can improve soil quality. Dehydrogenase activity seemed to be the most important microbial factor in organic carbon catabolism or humification. 相似文献
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77.
Hung-Hui Chen Liang-Cheng Chang Hsin-Yu Shan Jui-Pin Tsai 《Environmental Modeling and Assessment》2009,14(6):715-728
The hysteresis of capillary pressure versus saturation (P–S) relation is an important constitutive relation in multiphase flow, since the P–S relation is widely used to predict P–S relations in the simulation of the non-aqueous phase liquids (NAPLs). This work examined the performance of the scaling rule
on predicting the P–S relationship and then studied the joint impact of the scaling and hysteresis on the multiphase NAPL flow simulation. Various
experimental P–S values of distinct fluid pairs were compared with the scaled P–S curves using the scaling rule. The comparison indicated that the prediction of P–S is more accurate when the water–air P–S curve is used to scale other P–S curves. The joint impact of the scaling and hysteresis on the NAPLs flow simulation was then investigated by numerical simulation
studies. The NAPL simulator was used to simulate the outcome of several scenarios based on a system with water–NAPL–air in
a hypothetical sand tank. For both gasoline and trichloroethylene, the difference of the injected NAPL volume between no hysteretic
and hysteretic simulations over a given time period was the smallest when the water–air P–S curve was used to scale other P–S curves. Simulation results of this study are valuable references for predicting the distribution of NAPLs. 相似文献
78.
研究了PAN—S浸渍树脂对Co^2+的吸附性能。Co^2+吸附pH值范围为4.7—9.2,最佳pH值为5.4;达到最大吸附容量需25min,树脂对Co^2+平衡吸附容量是98mg/g干树脂,达到最大吸附容量平衡时用0.1mol/L的HNO,洗脱,洗脱率达98%。该方法建立了PAN—S-树脂富集一分离钴离子的分光光度测定方法,结果令人满意。 相似文献
79.
Zhang Y Chen Z Zhu B Luo X Guan Y Guo S Nie Y 《Environmental monitoring and assessment》2008,147(1-3):327-337
The objective of this study is to develop techniques for assessing and analysing land desertification in Yulin of Northwest China, as a typical monitoring region through the use of remotely sensed data and geographic information systems (GIS). The methodology included the use of Landsat TM data from 1987, 1996 and 2006, supplemented by aerial photos in 1960, topographic maps, field work and use of other existing data. From this, land cover, the Normalised Difference Vegetation Index (NDVI), farmland, woodland and grassland maps at 1:100,000 were prepared for land desertification monitoring in the area. In the study, all data was entered into a GIS using ILWIS software to perform land desertification monitoring. The results indicate that land desertification in the area has been developing rapidly during the past 40 years. Although land desertification has to some extent been controlled in the area by planting grasses and trees, the issue of land desertification is still serious. The study also demonstrates an example of why the integration of remote sensing with GIS is critical for the monitoring of environmental changes in arid and semi-arid regions, e.g. in land desertification monitoring in the Yulin pilot area. However, land desertification monitoring using remote sensing and GIS still needs to be continued and also refined for the purpose of long-term monitoring and the management of fragile ecosystems in the area. 相似文献
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