石油烃厌氧生物降解代谢产物研究进展

石油烃厌氧生物降解代谢产物的分析对于石油烃厌氧降解机制的研究、功能微生物的筛选以及微生物活动的原位监测具有指示性作用.综述了近年来石油烃厌氧生物降解代谢产物的研究进展.石油烃厌氧降解的初始活化方式主要包括脱氢羟基化、加延胡索酸以及羧化等.其中,加延胡索酸是不同种类的微生物通常采用的代谢方式.同时,将代谢产物按照气体、无机离子和有机酸进行分类,并针对各类物质特别是瞬时性、低浓度的有机酸类产物常采用的分析方法进行归纳.通过实例强调了代谢产物作为潜在生物标记物的应用,并对石油烃厌氧降解代谢产物分析方法的发展提出展望.图3参58     

Water Supply and Stormwater Management Benefits of Residential Rainwater Harvesting in U.S. Cities

This article presents an analysis of the projected performance of urban residential rainwater harvesting systems in the United States (U.S.). The objectives are to quantify for 23 cities in seven climatic regions (1) water supply provided from rainwater harvested at a residential parcel and (2) stormwater runoff reduction from a residential drainage catchment. Water‐saving efficiency is determined using a water‐balance approach applied at a daily time step for a range of rainwater cistern sizes. The results show that performance is a function of cistern size and climatic pattern. A single rain barrel (190 l [50 gal]) installed at a residential parcel is able to provide approximately 50% water‐saving efficiency for the nonpotable indoor water demand scenario in cities of the East Coast, Southeast, Midwest, and Pacific Northwest, but <30% water‐saving efficiency in cities of the Mountain West, Southwest, and most of California. Stormwater management benefits are quantified using the U.S. Environmental Protection Agency Storm Water Management Model. The results indicate that rainwater harvesting can reduce stormwater runoff volume up to 20% in semiarid regions, and less in regions receiving greater rainfall amounts for a long‐term simulation. Overall, the results suggest that U.S. cities and individual residents can benefit from implementing rainwater harvesting as a stormwater control measure and as an alternative source of water.     

SO_2体积分数对ZL50活性炭吸附脱硫行为的影响和动力学分析

通过动态吸附烟气脱硫实验,考察了烟气中不同SO2体积分数对ZL50脱硫脱硝活性炭脱硫行为的影响,并进行了动力学分析.随着烟气中SO2体积分数增大,脱硫率和ZL50脱硫脱硝活性炭的活性度下降;SO2吸附量和吸附速率增大.模拟结果表明,Bangham模型模拟效果最优,SO2的催化氧化反应对化学吸附有重要影响;Lagergren准一级吸附速率常数随SO2进口体积分数的增加而增大,表明SO2的催化氧化反应在吸附前期可能为速控步骤.推导和定义了Lagergren模型和Bangham模型的初始吸附速率;推导了文献上的Ho模型和Elovich模型的初始速率式。定义的Bangham初始吸附速率与初始吸附速率实验值吻合最好;建立的Bangham吸附反应动力学模型能较好地描述SO2动态吸附速率.结果表明,SO2的初始反应速率分级数为1或接近1,而O2和水蒸气的初始速率分级数分别为0.15～0.20和0.45～0.50之间的常数.     

城市雨洪资源利用经济价值评价研究

对城市雨洪的合理利用,有助于城市防止内涝、减少灾害、改善水环境,同时能够解决城市水资源短缺,有助于实现水资源可持续利用。文章通过对西安市雨洪资源量的分析,建立了雨洪资源利用的经济效益评价指标,同时,通过分析雨洪资源的利用对国民经济的促进作用,构建了雨洪资源利用的经济价值评价模型,确定了1998～2007年西安市雨洪资源利用对国民经济的贡献量,为下一步建立系统动力学模型分析资源与经济的相互影响奠定了基础。同时,利用该模型测算出2007年西安市雨水利用量约为234万m3,2006年雨洪资源的合理利用推动GDP增长104607.9万元,2007年雨洪资源的合理利用推动GDP增长125787.2万元,但同时尚有76556.61万m3的雨洪资源未得到合理利用。     

Role of the reduction site in the fluorinated or sulfated TiO2 photocatalytic process

In this article,the effects of TiO_2 surface fluorination and sulfation,on the active oxygen species formed at the reduction site in the photocatalytic process,namely O_2~(?) and H_2O_2,were investigated from a new perspective.The superoxide radical,(O_2~(?)),was determined by colorimetry of nitroblue tetrazolium,a prominent O_2~(?) scavenger.Hydrogen peroxide (H_2O_2) was estimated by using the iodide-starch method.In the naked TiO_2 photocatalysis,O_2~(?) though less reactive,was a very important intermediate.When the TiO_2 surface was fluorinated,more O_2~(?) and H_2O_2 were produced,which indicated that the surface modification could greatly reduce the recombination of photogenerated electrons and holes,thus enhancing the photocatalytic rate.In the sulfated system,photocatalysis proceeded with a more complicated mechanism.These results added support to the view of fluoride-induced enhancement and sulfide's nonappreciable inhibition effect.     

2,2’,4,4’—四溴联苯醚对2种赤潮微藻种间竞争的影响

基于Logistic种群增长模型,研究了2,2’,4,4’—四溴联苯醚(BDE-47)的亚急性毒性胁迫对不同初始接种生物量比的赤潮异弯藻(Heterosigmaakashiwo)和米氏凯伦藻(Kareniamikimotoi)种间作用的影响.结果发现:不同的初始接种生物量比影响微藻间的竞争.加入0.05、0.25 mg/LBDE-47后,对于K. mikimotoi而言,不同初始生物量比的处理组表现出高浓度组的最大环境容纳量、种群瞬时增长率均大于低浓度组(P<0.05),而H. akashiwo高浓度组的最大环境容纳量、种群瞬时增长率均小于低浓度组(P<0.05).微藻之间的竞争表现出向着对K. mikimotoi有益方向发展的规律,因此一定浓度下的BDE-47干扰了两种微藻之间的竞争.     

共青生态小区雨水资源化系统规划设计

文章介绍了共青数字生态城中生态小区雨水资源化利用的设计规划过程。以B小区为例,对该小区的雨水截污措施、屋面雨水收集、道路雨水收集、绿地收集及雨水处理、雨水综合利用等方面的规划设计进行了分析说明。将雨水作为一种资源再生后加以利用,是社会、经济持续发展的必然选择,具有较好的环境效益和社会效益。     

Cation exchange resin supported nanoscale zero-valent iron for removal of phosphorus in rainwater runoff

Self-made cation exchange resin supported nanoscale zero-valent iron （R-nZVI） was used to remove phosphorus in rainwater runoff. 80% of phosphorus in rainwater runoff from grassland was removed with an initial concentration of 0.72 mg. L-1 phosphorus when the dosage of R-nZVl is 8 g per liter rainwater, while only 26% of phosphorus was removed when using cation exchange resin without supported nanoscale zero-valent iron under the same condition. The adsorption capacity of R-nZVI increased up to 185 times of that of the cation exchange resin at a saturated equilibrium phosphorous concentration of 0.42 mg. L-1. Various techniques were implemented to characterize the R-nZVI and explore the mechanism of its removal of phosphate. Scanning electron microscopy （SEM） indicated that new crystal had been formed on the surface of R-nZVI. The result from inductive coupled plasma （ICP） indicated that 2.1% of nZVI was loaded on the support material. The specific surface area was increased after the load of nanoscale zero-valent iron （nZVI）, according to the measurement of BET-N2 method. The result of specific surface area analysis also proved that phosphorus was removed mainly through chemical adsorption process. X-ray photoelectron spectroscopy （XPS） analysis showed that the new product obtained from chemical reaction between phosphate and iron was ferrous phosphate.     

Acid Deposition in the Tuscan Appennines During the Dry Period 1988-89

The typical parameters of acid precipitation are evaluated in the forest of Vallombrosa (Tuscan Appennines) during the dry period 1988-89. Individual rain events (dry and wet deposition) were sampled in a clearing of the forest and below the canopy of an evergreen tree as well as a deciduous broadleaf tree.

In atmospheric precipitation the pH values usually vary around 4.4, with neutralization in the hot season due to calcareous material from distant sources. Relatively large concentrations of Pb and Cd are found in rain, but only in a small amount in canopy leachate. Aluminium, manganese and iron are more significantly washed off than Pb and Cd.     

Sustainable design of sanitation system based on material and value flow analysis for urban slum in Indonesia

Material flow analysis (MFA) and value flow analysis (VFA) were applied to the sanitation system in an urban slum in Indonesia. Based on the results of the MFA and VFA, garbage and excreta disposal costs were evaluated to be 0.7% and 1.1%, respectively, of per capita income. Such value flows seem reasonable in light of the recognized affordability to pay (ATP) standard. However, current excreta disposal methods create negative impacts on downstream populations. Because such disadvantages do not go back to disposers, but passed to downstream, the current value flow structure does not motivate individual toilet users to install treatment facility. Based on current material and value flow structures, a resource recycling sanitation system scenario was examined. Based on VFA, an affordable initial cost for such a system was calculated; this was found to be comparable in price to a cheaper composting toilet that is currently available in the market.