长江口及其邻近水域溶解无机氮的分布变化特征

根据2004年4个航次的调查资料,研究了长江口及其邻近水域溶解无机氮的分布变化特征。结果表明,高浓度溶解无机氮集中分布在河口附近。一般来讲,近岸硝酸盐浓度上层高于下层,远岸与之相反。由于生物和化学作用的影响,亚硝酸盐和铵盐垂直断面分布较为复杂。随着长江径流量的增加与减小、冲淡水势力范围的扩大与缩小,硝酸盐季节分布随之变化,然而,亚硝酸盐春季浓度较高,铵盐冬季浓度远大于其它季节。各月DIN/PO4-P比值远高于Redfield比值。与1985~1986年相比,20余年溶解无机氮增加了2.2倍,DIN/PO4-P比值升高了1.4倍,这主要取决于溶解无机氮浓度的增加。溶解无机氮在河口的转移除了生物活动的影响外,主要受海水稀释作用的控制。     

硫氮比对废水脱氮与沼气脱硫耦联功能茵的影响

从废水脱氮与沼气脱硫耦联反应器中分离到了2株同步脱氮除硫功能菌--荧光假单胞菌(Pseudomonas fluorescens)和铜绿假单胞菌(Pseudomonas aeruginosa).在pH 7.0,温度30℃,无供氧,培养时间2 d的条件下进行了2株功能菌纯培养的同步脱氮除硫效果试验,研究了不同硫氮比对同步脱...     

Catalytic oxidation of benzene over nanostructured porous Co3O4-CeO2 composite catalysts

The three-dimensional structured Co₃O₄-CeO₂ oxides with Co/Ce molar ratio 16:1 gave the highest catalytic activity, which provided more surface hydroxyl groups and more surface oxygenated species.     

改良UCT分段进水工艺处理生活污水性能优化研究

在某大型污水处理厂采用中试规模的改良UCT分段进水脱氮除磷工艺处理低COD/N生活污水,重点研究了流量分配比和原水营养元素比（COD/N、COD/P和TN/P）对工艺脱氮除磷性能的影响,目的是分析探索工艺对有机物和氮磷去除机制和污泥特性.连续运行试验表明,该工艺取得稳定高效的去除性能.在进水COD负荷为0.79～0.9...     

不同碳氮磷源改良剂对铅锌尾矿废弃地植被与土壤性质的影响

开展野外田间试验,在铅锌尾矿废弃地上添加不同碳氮磷源改良剂进行植被重建,从植物生长、营养元素、土壤酶活性、尾矿及植物重金属含量等方面研究其对铅锌尾矿废弃地的改良效果.结果表明:①添加不同碳氮磷源改良剂促进了植物在尾矿上定居和生长,植被盖度从6个月的2. 0%～20. 0%增长到30个月的62. 5%～98. 5%;生物量从6个月的9. 4～115g·m-2增长到30个月的389. 0～2 358. 3 g·m-2.②添加不同碳氮磷源改良剂增加了尾矿营养元素含量(有机碳、水溶性碳、硝态氮和有效磷分别增加了6. 0%～93. 3%、1. 3%～49. 3%、12. 3%～214. 7%和2. 7%～81. 3%)和提高了土壤酶活性(脱氢酶、β-葡萄糖苷酶、脲酶和磷酸酶活性分别提高了0. 3～2. 8、0. 1～1. 4、0. 1～0. 6和0. 1～0. 5倍).③添加不同碳氮磷源改良剂不同程度地降低了尾矿中重金属有效态含量(DTPA-Cd、DTPA-Cu、DTPA-Pb和DTPA-Zn分别下降了2. 5%～40. 2%、1. 4%～25. 6%、1. 4%～15. 2%和0. 4%～24. 9%)和植物体内重金属(Cd、Cu、Pb和Zn分别下降了12. 1%～58. 7%、6. 4%～46. 0%、20. 2%～68. 0%和11. 7%～58. 1%)含量.④Pearson相关性分析表明,植被盖度、生物量与尾矿营养元素和土壤酶活性呈显著正相关,与尾矿重金属有效态含量呈显著负相关;植物地上部分重金属含量与尾矿重金属有效态含量、营养元素和土壤酶活性相关性不明显.综合分析表明,碳氮磷源改良剂是铅锌尾矿废弃地植被恢复良好的改良材料.     

5种结构障碍物对火焰传播影响的试验研究

为了研究障碍物结构对预混甲烷管道内火焰传播速度和峰值超压的影响,自行设计一套火焰加速系统。在火焰加速管道上安装光电传感器和压力传感器分别测定火焰传播速度和超压,试验中选取5种结构障碍物,即平板、长方体、三棱柱、四棱柱和圆柱,其阻塞比分别为20%,40%和60%3种。研究结果表明:初始阶段障碍物阻碍火焰传播,当火焰越过障碍物后,障碍物能显著加速火焰传播。随着阻塞比增加,相同结构障碍物的火焰传播速度总体上不断增加,而峰值超压先变大后减小。相同阻塞比下,平板、三棱柱对火焰传播速度和超压影响相对较大;长方体居中;圆柱、四棱柱对增加火焰传播速度和超压作用相对较小。较小阻塞比障碍物管道内超压与无障碍物管道中的超压相比显著增加,但此后,管道中超压随阻塞比变化不明显。     

短程反硝化的启动及多参数优化下NO2--N积累特性

采用本实验室长期培养的厌氧（S-A）、好氧（S-O）和交替厌氧/好氧（S-A/O）活性污泥为种泥,分别启动短程反硝化SBR反应器R1、R2和R3,控制进水C/N比为3,缺氧搅拌时间为1h时,在第15d、7d和4d亚硝酸盐积累率（NAR）分别达到75.34%、84.51%和86.23%.选取C/N比、初始pH值、缺氧搅拌时间和初始NO₃^--N浓度对NAR进行四因素三水平响应面实验,方差分析结果表明,以上因素对NAR均有显著影响（P<0.05）,模型R²为0.983.通过模型预测得最佳运行条件：C/N比为3.16,初始pH值为8.51,缺氧搅拌时间为1.27h,初始NO₃^--N浓度为60mg/L的条件下,NAR高达91.32%.     

Total Lead and Stable Lead Isotopes in Stockholm Sediments

Lead (Pb) in the environment is derived from both naturaland anthropogenic sources. The aim of this study is to estimate the isotopic signature of anthropogenic Pb in sediments from a highly contaminated area (Stockholm), to discuss the influence of different sources on this signature, and to suggest natural Pb background concentrations. Also distribution patterns and differences between different water areas in Stockholm have been studied, both by total Pb and stable Pb isotopes. In 1993, sediment samples were collected at 24 stations in the Stockholm area and analysed for total Pb, zirconium (Zr), scandium (Sc) and stable Pb isotopes (^{204, 206-208}Pb). Total Pb data show that the Stockholm sediments are severely contaminated by Pb. The contamination seems to be rather local since the small lakes surrounding the central parts of Stockholm are much less effected than the central parts. Stockholm is clearly influenced by anthropogenic and natural sources, but in some of the small lakes also by Pb in zircons from the geological basement. The anthropogenic Pb in Stockholm has typical ²⁰⁷Pb/²⁰⁶Pb ratios of 0.85–0.89 and ²⁰⁸Pb/²⁰⁴Pb ratios of 36–38, which are distinct from natural sources. Pb/Sc ratios suggest that the natural background Pb concentration is 10–20 mg kg^-1 d.w.     

Re-examining the water affordability: A comparison of alternative measures

Water affordability is determined by the percentage of income households that must allocate to municipal water services, while factoring in essential or basic needs water use. With the rise in water prices reported in most areas of the country along with somewhat stagnant income growth—a combination that suggests ceteris paribus—more of a household's disposable income is being spent on water services. This paper adds to the discussion in three ways. First, given the lack of a consistent definition for “affordability” and the subjective connotation associated with such a term, we develop and compare five different water expenditure ratios, including two different measures of water for essential needs, as well as measures for indoor, efficient, and actual water use. Second, because of the granularity of our data, we illustrate how such “affordability” measures can vary significantly within a water district and thus highlight how using district- or county-level income measures can mask the degree to which affordability is an issue for households living in low-income block groups. Our results indicate that the choice of income measure and type of water service use can influence affordability measures substantially.