斜发沸石对城市污水处理厂二级出水中氨氮的处理效果研究

通过静态实验,研究天然斜发沸石去除城市污水处理二级出水中氨氮的性能。研究结果表明,投加量越大,沸石对废水中氨氮的去除率越高,但是吸附容量越低;沸石对氨氮的去除具有短时间内快速吸附,然后缓慢平衡的特点;粉末状沸石对氨氮的去除效果明显好于颗粒状沸石;pH对氨氮去除率有显著影响,pH值为6时,沸石对氨氮的去除率最高。NaCl和NaOH溶液对沸石的改性具有明显的效果,HCl溶液对沸石的改性作用不明显。     

流化床生活垃圾焚烧炉污染物排放监控管理

依据生活垃圾循环流化床燃烧热电厂竣工环保验收及例行环保监测数据,提出了影响生活垃圾焚烧过程特征污染物排放的主要因素是炉温和燃烧过程的喷钙与脱氯,建议增加炉温在线监测为生活垃圾焚烧污染物排放的管理措施,在例行监测项目中增加粉煤灰钙含量监测,保证生活垃圾的完全燃烧、较高脱氯效率,降低二噁英的产生与排放。     

Eutrophication in the Yunnan Plateau lakes: the influence of lake morphology, watershed land use, and socioeconomic factors

Introduction  

Lakes play an important role in socioeconomic development and ecological balance in China, but their water quality has deteriorated considerably in recent decades. In this study, we investigated the spatial–temporal variations of eutrophication parameters (secchi depth, total nitrogen, total phosphorus, chemical oxygen demand, chlorophyll-a, trophic level index, and trophic state index) and their relationships with lake morphology, watershed land use, and socioeconomic factors in the Yunnan Plateau lakes.     

脉冲磁场对电厂循环冷却水中异养菌的灭活

为了控制微生物繁殖对电厂循环冷却水系统造成的危害,研究了脉冲电源发生器与线圈绕组相连产生的脉冲磁场对循环水中异养菌的灭活影响,并对灭活关键因素进行了分析。实验结果表明,脉冲磁场对电厂循环冷却水中的异养菌有灭活作用;灭活率对频率和输出电压有选择性,并且随着作用时间和温度的升高而升高;在扫频范围100～1000 Hz、输出电压3 V、单次作用时间为15 s,温度45℃时,异养菌灭活率达到78.8%。     

Contrasting effects of black carbon amendments on PAH bioaccumulation by Chironomus plumosus larvae in two distinct sediments: role of water absorption and particle ingestion

Two sediment matrices with different characteristics were amended with chars from different sources for bioaccumulation assay with filter-feeding Chironomus plumosus larvae. Chars greatly decreased porewater concentrations of PAHs (C_iw) measured using polyethylene devices in sediments. In organic rich sediment matrix-based systems where suspended char particles were absent, PAH concentrations in larvae (C_iB) were significantly correlated with C_iw, and there was no difference in water-based bioaccumulation factors (BAFs) between different treatments, suggesting that water absorption was the main contaminant uptake route for larvae. In organic poor sediment matrix-based systems where suspended char particles were present, poor Pearson correlation between C_iB and C_iw was found, but there was a significant linear increase of BAF values with char contents, which indicated that ingestion of suspended char particles could also be important for PAH bioaccumulation. Therefore, we need to rethink of the effectiveness and risks for the application of black carbon to sediment/soil remediation.     

Chemical composition of PM10 and PM2.5 collected at ground level and 100 meters during a strong winter-time pollution episode in Xi'an, China

An intensive sampling of aerosol particles from ground level and 100 m was conducted during a strong pollution episode during the winter in Xi'an, China. Concentrations of water-soluble inorganic ions, carbonaceous compounds, and trace elements were determined to compare the composition of particulate matter (PM) at the two heights. PM mass concentrations were high at both stations: PM10 (PM with aerodynamic diameter < or =10 microm) exceeded the China National Air Quality Standard Class II value on three occasions, and PM2.5 (PM with aerodynamic diameter < or =2.5 microm) exceeded the daily U.S. National Ambient Air Quality Standard more than 10 times. The PM10 organic carbon (OC) and elemental carbon (EC) were slightly lower at the ground than at 100 m, both in terms of concentration and percentage of total mass, but OC and EC in PM2.5 exhibited the opposite pattern. Major ionic species, such as sulfate and nitrate, showed vertical variations similar to the carbonaceous aerosols. High sulfate concentrations indicated that coal combustion dominated the PM mass both at the ground and 100 m. Correlations between K+ and OC and EC at 100 m imply a strong influence from suburban biomass burning, whereas coal combustion and motor vehicle exhaust had a greater influence on the ground PM. Stable atmospheric conditions apparently led to the accumulation of PM, especially at 100 m, and these conditions contributed to the similarities in PM at the two elevations. Low coefficient of divergence (CD) values reflect the similarities in the composition of the aerosol between sites, but higher CDs for fine particles compared with coarse ones were consistent with the differences in emission sources between the ground and 100 m.     

气相色谱-质谱法测定水中挥发性有机物的测量不确定度评定

根据测量不确定度评定与表示理论,采用气相色谱一质谱法测定水中挥发性有机物。以氯乙烯为例,通过计算和评定,得出当氯乙烯的测量结果为4．99μg／L时,取包含因子k=2（约95％置信概率）,扩展不确定度U=0．96μg／L。该不确定度评定方法在实际工作中具有较强的实用价值。     

江苏省不同营养状况湖泊底栖动物群落结构与多样性比较

为了解江苏省湖泊底栖动物群落结构和多样性并研究其对水环境质量变化的响应,于2012年春秋两季对江苏省16个湖泊51个采样点湖泊底栖动物群落结构与多样性以及湖泊综合营养状态指数进行调查,分析水质指标与底栖动物指数间Pearson相关关系。结果表明,江苏省16个湖泊营养状态指数范围为35.5~66.4,其中约81.2%的湖泊处于轻度-中度富营养状态,表明水质从好到中度污染;湖泊底栖动物优势种为寡毛类的霍甫水丝蚓(Limnodrilus hoffmeisteri),优势度为13.0%;香浓多样性指数(Shannon-Wiener diversity index)范围为0.00~2.20,级别范围由极贫乏到较丰富状态,表明水质污染程度从重度到轻度污染。从全省尺度看,水质评价结果与生物学(香浓多样性指数、Pielou均匀度指数和Biotic Index(BI)指数)评价结果存在一定差异。与历史数据相比,江苏省湖泊底栖动物清洁敏感物种减少甚至消失,总体群落结构趋于小型化。16个湖泊水体总氮和总磷与底栖动物密度呈显著负相关,而综合营养状态指数与底栖动物指数(香浓多样性指数、Pielou均匀度指数和BI指数)间关系不显著。上述研究结果表明综合营养状态指数无法完全客观反映湖泊水生态健康状况,因此需要综合水质、水文、水生生物、生境状况等因素发展新的评价指标体系。     

Preparation,characterization, and photocatalytic activity evaluation of Fe–N-codoped TiO2/fly ash cenospheres floating photocatalyst

Nitrogen-doped titanium dioxide (TiO₂) and Fe–N-codoped TiO₂ layers on fly ash cenospheres (FAC) as floating photocatalyst were successfully prepared through sol–gel method. Photocatalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), ultraviolet (UV)–Vis diffuse reflectance spectroscopy (DRS), and nitrogen adsorption analyses for Brunauer–Emmett–Teller (BET) specific surface area. Photocatalytic efficiency of the prepared catalyst was evaluated through using the decomposition of Rhodamine B (RhB) as a model compound under visible light irradiation. Photocatalytic activity and kinetics of catalyst under visible light were detected in details from different Fe/Ti mole ratios by detecting photodegradation of RhB. Experimental results show that when the calcination temperature was 550 °C, the dosage of FAC was 3.0 g, and the mole ratio of Fe/Ti was 0.71 %; the synthesized Fe–N-TiO₂/FAC photocatalyst presented as anatase phase and that N and Fe ions were doped into TiO₂ lattice. The material’s specific surface area was 34.027 m²/g, and UV–Vis diffuse reflectance spectroscopy shows that the edge of the photon absorption has been red shifted up to 400–500 nm. Fe–N-codoped titanium dioxide on FAC had excellent photocatalytic activity during the process of photodegradation of RhB under visible light irradiation.

     

环保型钻井液的研究应用现状及发展趋势

介绍与分析了现阶段国内外环保型钻井液及其处理剂的特点和研究现状。推荐了钻井液体系环保指标及毒性的评价方法。指出制约中国环保型钻井液技术开发的因素,对环保型钻井液技术研究的重点和发展趋势进行了分析。指出环保型钻井液的发展趋势,强调无毒性硅酸盐钻井液是今后研究的重点。