有机废气中VOC的回收方法

介绍了炭吸附法、冷凝法和膜分离法回胥机废报中ＶＯＤ的原理、工艺流程和工业应用情况，并对这些方法进行了比较，指出了适用范围。     

模拟降雨径流作用下红壤坡面侵蚀水动力学机制

土壤侵蚀过程受控于侵蚀外营力和土壤抗侵蚀性能,深入理解坡面流水动力学特性及其侵蚀动力是研究土壤侵蚀动力学机制的基础。利用可变坡土槽,通过不同雨强(60、90和120 mm/h)和径流冲刷(10、15和20 L/min)组合模拟试验,研究了第四纪黏土红壤坡面水流的水动力学特征参数及其与土壤侵蚀量间的关系。结果显示:降雨和径流冲刷影响了坡面产流产沙过程和坡面流水力学特性,其中平均流速v、平均水深h、雷诺数Re和水流功率ω均随降雨强度和上方来水流量的增加而增大,相对水深曼宁糙率n/h则减小,其水力学他参数(弗如德数Fr、阻力系数f和水流剪切力τ)变化规律不明显。坡面水流平均速度取值范围为0.21~0.45 m/s,平均水深取值范围为5.6~9.4 mm,在试验条件下红壤坡面侵蚀水流流态大部分均处于"紊流-急流区"。不论从径流角度看或是从泥沙角度分析,由相对水深和曼宁糙率系数两种水动力因子共同组成的复合水动力特征参数-相对水深曼宁糙率,是表征不同上方来水流量和降雨强度条件下第四纪粘土红壤坡面侵蚀特征的水动力参数。     

Carbon dioxide emissions from cities in China based on high resolution emission gridded data

Based on the China high resolution emission gridded data (1 km spatial resolution), this article is aimed to create a Chinese city carbon dioxide (CO₂) emission data set using consolidated data sources as well as normalized and standardized data processing methods. Standard methods were used to calculate city CO₂ emissions, including scope 1 and scope 2. Cities with higher CO₂ emissions are mostly in north, northeast, and eastern coastal areas. Cities with lower CO₂ emissions are in the western region. Cites with higher CO₂ emissions are clustered in the Jing-Jin-Ji Region (such as Beijing, Tianjin, and Tangshan), and the Yangtze River Delta region (such as Shanghai and Suzhou). The city per capita CO₂ emission is larger in the north than the south. There are obvious aggregations of cities with high per capita CO₂ emission in the north. Four cities among the top 10 per capita emissions (Erdos, Wuhai, Shizuishan, and Yinchuan) cluster in the main coal production areas of northern China. This indicates the significant impact of coal resources endowment on city industry and CO₂ emissions. The majority (77%) of cities have annual CO₂ emissions below 50 million tons. The mean annual emission, among all cities, is 37 million tons. Emissions from service-based cities, which include the smallest number of cities, are the highest. Industrial cities are the largest category and the emission distribution from these cities is close to the normal distribution. Emissions and degree of dispersion, in the other cities (excluding industrial cities and service-based cities), are in the lowest level. Per capita CO₂ emissions in these cities are generally below 20 t/person (89%) with a mean value of 11 t/person. The distribution interval of per capita CO₂ emission within industrial cities is the largest among the three city categories. This indicates greater differences among per capita CO₂ emissions of industrial cities. The distribution interval of per capita CO₂ emission of other cities is the lowest, indicating smaller differences of per capita CO₂ emissions among this city category. Three policy suggestions are proposed: first, city CO₂ emission inventory data in China should be increased, especially for prefecture level cities. Second, city responsibility for emission reduction, and partitioning the national goal should be established, using a bottom-up approach based on specific CO₂ emission levels and potential for emission reductions in each city. Third, comparative and benchmarking research on city CO₂ emissions should be conducted, and a Top Runner system of city CO₂ emission reduction should be established.     

Does Including Soil Moisture Observations Improve Operational Streamflow Forecasts in Snow‐Dominated Watersheds?

Changing climate and growing water demand are increasing the need for robust streamflow forecasts. Historically, operational streamflow forecasts made by the Natural Resources Conservation Service have relied on precipitation and snow water equivalent observations from Snow Telemetry (SNOTEL) sites. We investigate whether also including SNOTEL soil moisture observations improve April‐July streamflow volume forecast accuracy at 0, 1, 2, and 3‐month lead times at 12 watersheds in Utah and California. We found statistically significant improvement in 0 and 3‐month lead time accuracy in 8 of 12 watersheds and 10 of 12 watersheds for 1 and 2‐month lead times. Surprisingly, these improvements were insensitive to soil moisture metrics derived from soil physical properties. Forecasts were made with volumetric water content (VWC) averaged from October 1 to the forecast date. By including VWC at the 0‐month lead time the forecasts explained 7.3% more variability and increased the streamflow volume accuracy by 8.4% on average compared to standard forecasts that already explained an average 77% of the variability. At 1 to 3‐month lead times, the inclusion of soil moisture explained 12.3‐26.3% more variability than the standard forecast on average. Our findings indicate including soil moisture observations increased statistical streamflow forecast accuracy and thus, could potentially improve water supply reliability in regions affected by changing snowpacks.     

Volatile Organic Compounds from Coal Tar and Soil Vapor Samples at MGP Sites

This study characterized organic compounds found in New York State manufactured gas plant (MGP) coal tar vapors using controlled laboratory experiments from four separate MGP sites. In addition, a limited number of deep (0.3–1.2 m above coal tar) and shallow (1.2–2.4 m above coal tar) soil vapor samples were collected above the in situ coal tar source at three of these sites. A total of 29 compounds were consistently detected in the laboratory-generated coal tar vapors at 50°C, whereas 24 compounds were detected at 10°C. The compounds detected in the field sample results were inconsistent with the compounds found in the laboratory-generated samples. Concentrations of compounds in the shallow soil vapor sample were either non-detectable or substantially lower than those found in deeper samples, suggesting attenuation in the vadose zone. Laboratory-generated data at 50°C compared the (% non-aromatic)/(% aromatic) ratio and indicated that this ratio may provide good discrimination between coal tar vapor and common petroleum distillates.     

基于白碳黑的水化硅酸钙制备及其磷回收特性简

以白碳黑、硅灰、硅藻土和硅胶筛选硅质原料,并与钙质原料电石渣制备了水化硅酸钙。借助XRF、BET、FTIR等表征手段,通过多次重复除磷实验,研究了硅质原料特性对水化硅酸钙回收磷性能的影响。结果表明,白碳黑具有极高的反应活性,因此可作为制备具有磷回收特性的水化硅酸钙的硅质原料。结合XRD等表征发现,白碳黑的有效利用率是影响水化硅酸钙回收磷性能的关键,该利用率取决于白碳黑与电石渣的摩尔配比以及水热反应温度。当电石渣与白碳黑的摩尔比为1.6：1,反应温度为170℃时,白碳黑具有最佳的利用效率。该条件制备的水化硅酸钙可作为晶种,在其表面结晶形成羟基磷灰石,从而达到磷回收的目的,磷回收后固体物质中的磷含量为19.05%。     

微波再生载苯酚活性炭过程中再生产物分析

研究了载氮气和无载气2种条件下,微波再生载苯酚活性炭过程中再生产物的成分和苯酚随再生过程的去向分布。结果表明,无载气时,微波功率越高,再生反应器内温度越高,吸附质的高温裂解反应越彻底,再生产物以挥发性气体为主,有机质种类很少;而当微波功率较低或载氮气再生时,反应器内温度相对较低,苯酚难以被彻底分解,再生产物中含多种复杂的链状或环状有机物。此外,载氮气时,经气提、挥发而去除的苯酚量约占总吸附量的一半,再生炭上无苯酚残留,活性炭吸附性能可完全恢复乃至优化;无载气时,经挥发而去除的苯酚量只有19.9%,其余大量苯酚则在微波作用下裂解或缩合为其他物质随尾气而去除,且再生炭上仍有少量苯酚未被解吸出来。因此,前者活性炭再生的效果优于后者。     

5种植物材料的水解释碳性能及反硝化效率

碳源在硝酸盐去除过程中起电子供体的作用,是生物反硝化反应的关键物质之一。为解决污水处理脱氮时碳源不足抑制反硝化反应造成脱氮效率低的问题,本研究选取风车草、甘蔗渣、芦竹、美人蕉和稻草秆5种植物材料作为反硝化碳源,探讨不同植物材料的水解释碳能力和释放规律;并进一步以其水解液作为外加碳源,探讨其对反硝化脱氮效率的影响。研究结果表明,植物材料水解释碳过程符合二级动力学反应规律,不同植物材料的释碳能力具有显著性差异,以甘蔗渣在固液比1∶80时COD释放当量最大,为45.45 mg/L;添加植物水解液可显著提高反硝化脱氮效率,以芦竹水解液脱氮效果最好,达到71.9%。此外,碳氮比是影响脱氮效率的重要因素之一,以碳氮比为9时反硝化脱氮效果最佳。     

A full-scale sequencing batch reactor system for swine wastewater treatment

A full-scale sequencing batch reactor (SBR) system was evaluated for its ability to remove carbon and nitrogen from swine wastewater. The SBR was operated on four, six-hour cycles each day, with each cycle consisting of 4.5 hours of “React,” 0.75 hours of “Settling”, 0.75 hours for “Draw” and “Fill.” Within each cycle, an amount of wastewater equivalent to about 5% of the reactor volume (5,500 litres) was removed and added. The SBR system was able to remove 82% of biochemical oxygen demand (BOD) and more than 75% of nitrogen. Even though the SBR effluent, with an average effluent BOD₅ of about 588 mg L^{? 1}, did not meet the discharge criteria, it enabled a reduction of the land base required for land application of swine wastewater by about 75%. Results indicated that the SBR system was a viable method for the treatment of swine wastewater.     

Application of a permethrin immunosorbent assay method to residential soil and dust samples

A low-cost, high throughput bioanalytical screening method was developed for monitoring cis/trans-permethrin in dust and soil samples. The method consisted of a simple sample preparation procedure [sonication with dichloromethane followed by a solvent exchange into methanol:water (1:1)] with bioanalytical detection using a magnetic particle enzyme-linked immunosorbent assay (ELISA). Quantitative recoveries (83–126 %) of cis/trans-permethrin were obtained for spiked soil and dust samples. The percent difference of duplicate ELISA analyses was within ± 20 % for standards and ± 35 % for samples. Similar sample preparation procedures were used for the conventional gas chromatography/mass spectrometry (GC/MS) analysis except that additional cleanup steps were required. Recoveries of cis/trans-permethrin ranged from 81 to 108 % for spiked soil and dust samples by GC/MS. The ELISA-derived permethrin concentrations were highly correlated with the GC/MS-derived sum of cis/trans-permethrin concentrations with a correlation coefficient (r) of 0.986. The ELISA method provided a rapid qualitative screen for cis/trans-permethrin in soil and dust while providing a higher sample throughput with a lower cost as compared to the GC/MS method. The ELISA can be applied as a complementary, low-cost screening tool to prioritize and rank samples prior to instrumental analysis for exposure studies.