火力发电厂飞灰对抗生素磺胺的吸附性能

研究了吸附时间、飞灰用量、初始溶液pH和振荡频率等因素对飞灰吸附去除水溶液中磺胺的影响,并对其吸附机理进行了初步探讨。研究结果表明,飞灰用量增大有利于提高其对磺胺的吸附去除率。在25℃、振荡频率150 r/min、飞灰用量50 g/L、磺胺浓度4 mg/L条件下吸附10 min,磺胺的吸附去除率可达到92.8%。电厂飞灰对磺胺的吸附符合二级动力学模型,属于单分子层吸附。     

铁铝复配混凝剂处理低温低浊水

针对北京某水库水在冬季呈现低温低浊特性,以此为原水的某水厂在该期间常会出现出水余铝超标现象的问题,通过烧杯实验研究不同投药量下聚合氯化铝(PAC)以及它与三氯化铁(FeCl3)不同复配比形成混凝剂对冬季北京某水库水的处理效果。结果表明,复配药剂存在最佳的Fe/Al摩尔复配比为1/5,此时余铝、有机物去除效果较其他配比混凝剂高。在此配比下,当PAC投药量为0.03 mmol/L时,水中残余铝量取得最低值0.0063 mg/L。相同投药量复配药剂的浊度去除效果比单独使用PAC的浊度去除效果略弱。当投药量为0.06 mmol/L时,Fe/Al摩尔比为1/5的复配混凝剂,能使浊度降至0.4 NTU左右。此外,复配药剂的投药量小,投药范围更宽,易于实际投药操作;同时复配药剂还适于常温及偏中性水源水的处理。规模为5 m3/h中试实验也证明,采用铁铝复配混凝剂连续运行,可获得良好的浊度、余铝去除效果。     

Assessment of Chlorophyll-a Concentration and Trophic State for Lake Chagan Using Landsat TM and Field Spectral Data

In this study, we present the digital evaluation of Landsat TM data and field spectral measurements for retrieving chlorophyll-a (chl-a) concentration and trophic state index in Lake Chagan of Northeast China. Chl-a concentration of the lake can be estimated from the band ratio (TM4/TM3) and the field spectral data at 670 nm (absorption peak) and at 700 nm (reflectance peak). The results show that the best determination coefficient (R ²) is 0.67 from the TM data, by which chl-a distribution can be mapped. Based on chl-a determination from laboratory analysis, field spectral and TM data, the modified trophic state index (TSI_M) was applied to assess the lake’s trophic state. With the available data in Lake Chagan, each algorithm demonstrates the similar result for assessing the lake’s chl-a and trophic state. Our results indicate that Landsat TM and field spectral data could be used effectively to determine chl-a concentration and evaluate the trophic state of Lake Chagan in the study.     

Performance of wastewater subsurface drip emitters at low and normal pressure.

Subsurface drip distribution is an important on-site wastewater treatment technique widely used with various soil types and restricted site conditions. This study evaluated the performance of five subsurface wastewater drip products under eight pressures, ranging from 0 to 310 kPa. Results showed that Netafim Bioline pressure-compensating emitters (Netafim Irrigation Inc., Fresno, California) had an application uniformity coefficient of 95% and a coefficient of variance (C(v)) of 4.9%. The average uniformity coefficient of Geoflow Wasteflow products (Geoflow USA, Charlotte, North Carolina) was 94.4%, with a C(v) value of 6.8%. Flowrate and pressure relationships were developed by analyzing low and normal operational pressure ranges, and R-square values ranged from 1.000 to 0.301. Geoflow pressure-compensating products were non-pressure-compensating emitters under low pressure. Netafim pressure-compensating emitters were partially pressure-compensating under low pressures. In normal operational pressure ranges, both Geoflow and Netafim products were fully pressure-compensating. Netafim pressure-compensating products were characterized as pressure-compensating over the full range of operational pressures.     

Effect of Ce doping of TiO2 support on NH3-SCR activity over V2O5-WO3/CeO2-TiO2 catalyst

CeO2–TiO2composite supports with different Ce/Ti molar ratios were prepared by a homogeneous precipitation method, and V2O5–WO3/CeO2–TiO2catalysts for the selective catalytic reduction（SCR） of NOx with NH3 were prepared by an incipient-wetness impregnation method. These catalysts were characterized by means of BET, XRD, UV–Vis,Raman and XPS techniques. The results showed that the catalytic activity of V2O5–WO3/TiO2 was greatly enhanced by Ce doping（molar ratio of Ce/Ti = 1/10） in the TiO2 support.The catalysts that were predominantly anatase TiO2 showed better catalytic performance than the catalysts that were predominantly fluorite CeO2. The Ce additive could enhance the surface adsorbed oxygen and accelerate the SCR reaction. The effects of O2 concentration, ratio of NH3/NO, space velocity and SO2 on the catalytic activity were also investigated. The presence of oxygen played an important role in NO reduction. The optimal ratio of NH3/NO was 1/1 and the catalyst had good resistance to SO2 poisoning.     

强化污水人工土快滤处理系统除氮效果的研究

传统的人工土处理系统对污水中氮的去除率较低,改进后的污水人工土处理系统由珍珠岩人工土硝化柱和原人工土反硝化柱构成。试验结果表明,硝化柱有较好的通气条件,对NH⁺₄－N的转化去除率为84％～98％;反硝化柱中碳氮比（BOD₅/NO^－_x－N）以3.0左右、水力停留时间为6h左右较适宜。原人工土快滤系统经强化处理后,对污水中氮的去除率有较大幅度的提高,全N去除率由45％提高到91％～96％,出水水质全N和NH⁺₄－N含量小于5mg/L,NO^－_x－N［（NO^－₃＋NO^－₂－N的含量远小于10mg/L。     

中国土壤对酸沉降的相对敏感性区划

以土壤类型,土地利用和湿度为生态因子,评价中国土壤对对酸沉降的相对敏感性,并利用地理信息系统的工具绘制了相对敏感性区划图。在评价土壤的缓能力时,除了以土壤的化学性质为指标外,还综合考虑了土壤质地和温度这２个重要因素使得评价方法更适合我国土壤理化性质差异大和南北温差大的特性,区划的结果表明,我国对酸沉降最敏感的地区主要分布在东北的大兴安岭地区,云南的南部和华南沿海地区,其交介东北地区,长江以南和青藏     

油田含油污泥与芦苇共热解实验研究

以北方某油田湿地芦苇与油田某污水处理厂剩余污泥为对象,利用同步热分析仪及静态热解炉研究油田含油污泥及含油污泥-芦苇混合物的热解特性,将静态热解过程数据与同步热分析TG(热重分析)、DTG(微分热重分析)、DSC(差示扫描量热分析)曲线结合,计算了终止温度、产物量等。结果表明:不同含油污泥样品其产物生成率差别不大,热解TG、DTG和DSC曲线有较大差别,添加一定比例的芦苇可以使含油污泥热解过程变得匀速缓和,5%(质量比)的芦苇添加量可以使热解残渣恒重温度降低约25℃。混掺芦苇的样品残渣呈分散颗粒状,无聚结现象,对热解结焦将产生一定抑制作用。     

Characteristics and source identification of fine particulate n-alkanes in Beijing, China

Ambient particulate n-alkanes were determined for fine particle (PM2:5) samples collected from Sep 2003 to July 2004 in Beijing, China. The average concentration of total n-alkanes (Pn-alkanes) from C11 to C34 was 425.72 ng/m3, ranged from 7.02 to 2893.28 ng/m3. The concentration distributions of n-alkanes homologues in this study exhibited peaks at C21 and C29 in heating season, and C29 in non-heating season. The average carbon preference index (CPI) value was 1.88 in the range of 1.18–3.88. The maximum CPI in summer indicated the contribution of biogenic origins such as plant wax; while the minimum CPI value in winter was probably a result of fossil fuel combustion. Preliminary estimation from these results showed that 59% of the n-alkanes in PM2:5 in Beijing summer originated from plant wax, while 74%–88% was from fossil fuel combustion in other three seasons. Source estimation was further performed using principal component analysis method. Two major components were yielded accounting for 57.3% and 30.9% of the total variance, which presented the fossil fuel and biogenic contribution, respectively.     

A novel four-way combining catalysts for simultaneous removal of exhaust pollutants from diesel engine

A novel four-way combining catalysts containing double layers was applied to simultaneously remove four kinds of exhaust pollutants(NOx,CO,HC and PM) emitted from diesel engine.The four-way catalysts were characterized using scanning electron microscope(SEM) and Ultraviolet visible diffuse reflectance spectroscopy(UV-Vis DRS).Their catalytic performances were evaluated by temperature-programmed reaction technology.The double layer catalysts could effectively remove the four main pollutants.The highest catalytic activity was given by the two-layered catalysts of La0.6K0.4CoO3/Al2O3 and W/HZSM-5.Under the simulated exhaust gases conditions,the peak temperature of the soot combustion was 421°C,the maximal conversion of NO to N2 was 74%,the temperature of the HC total conversion was 357°C,and the maximum conversion ratio of CO was 99%.