苏锡常地区PM2.5污染特征及其潜在源区分析

利用2014年12月—2015年11月苏锡常地区国控大气环境质量监测站发布的逐时数据,分析了研究区PM_(2.5)浓度的季节变化和空间分布特征,并利用HYSPLIT模型分析了大气污染物的输送路径及苏锡常地区PM_(2.5)的潜在源区.结果表明,苏锡常地区PM_(2.5)浓度日均值变化趋势基本一致,均呈现冬季高、夏季低的规律.PM_(2.5)浓度四季空间差异显著,不同监测站之间的差异较小.四季PM_(2.5)浓度与其它污染物之间相关性显著.单位面积污染物排放量与空气质量分布的空间错位,表明该地区PM_(2.5)污染与区域性污染物迁移有较大关系.苏锡常地区气流后向轨迹季节变化特征明显,冬、春、秋季的气流主要来自西北内陆地区,夏季气流以东南和西南方向输入居多.聚类分析表明,来自内陆的污染气流和来自海洋的清洁气流是苏锡常地区两种主要输送类型,外源污染气流不仅直接输送颗粒物,还贡献了大量的气态污染物.山东南部、江苏西部、安徽东部、浙江北部及江西西北地区对苏锡常冬季PM_(2.5)浓度贡献较大,春、夏、秋季的潜在源区主要分布在苏锡常本地和周边城市.     

温度对SBR生物脱氮效能及胞外聚合物的影响

本实验以人工模拟废水为研究对象,采用3组SBR反应器(R_(15℃)、R_(25℃)、R_(35℃)),重点考察了温度对生物脱氮效能、胞外聚合物(EPS)含量及其组分[蛋白质(PN)、多糖(PS)和核酸(DNA)]的影响.结果表明,高温条件有利于促进亚硝酸型生物脱氮体系的建立,显著提高氨氮去除性能.温度对EPS及其组分具有显著影响.随着温度的升高,EPS和TB-EPS含量逐渐降低,而LB-EPS含量逐渐升高,EPS以TB-EPS为主(占69.0%~79.5%),但TB-EPS/LB-EPS比值随着温度升高逐渐降低[3.8(15℃)→3.6(25℃)→2.2(35℃)].在EPS,LB-EPS和TB-EPS中PN和DNA含量随着温度升高而降低,LB-EPS和EPS中PS含量随温度升高而增加.而TB-EPS中PS含量随温度升高而降低,且25℃是各组分浓度变化重要折点.在15℃和25℃时,PN为TB-EPS和LB-EPS的主要成分,PS次之,DNA最少,35℃时,PS成为主要成分,PN次之,DNA最少.此外,本研究也发现,在15℃和25℃时,EPS含量在硝化过程中逐渐增大,反硝化过程中逐渐降低.     

通过剖析达钢二次能源综合利用分析钢铁行业节能减排潜力

二次能源综合利用是我国钢铁行业完成节能减排既定目标的技术关键.本文通过对达钢二次能源综合利用的剖析,评述了钢铁行业节能减排的潜力.     

Source apportionment of ambient PM10 in urban areas of Wuxi, China

A total of 168 PM₁₀ samples were collected during the year of 2005 at eight sites in the city of Wuxi in China. Fifteen chemical elements, three water-soluble ions, total carbon and organic carbon were analyzed. Six source categories were identified and their contributions to ambient PM₁₀ in Wuxi were estimated using a nested chemical mass balance method that reduces the effects of colinearity on the chemical mass balance model. In addition, the concentrations of secondary aerosols, such as secondary organic carbon, sulfate and nitrate, were quantified. The spatially averaged PM₁₀ was high in the spring and winter (123 ??g·m^?3 and low in the summer-fall (90 ??g·m^?3). According to the result of source apportionment, resuspended dust was the largest contributor to ambient PM₁₀, accounting for more than 50% of the PM₁₀ mass. Coal combustion (14.6%) and vehicle exhaust (9.4%) were also significant source categories of ambient PM₁₀. Construction and cement dust, sulfates, secondary organic carbon, and nitrates made contributions ranging between 4.1% and 4.9%. Other source categories such as steel manufacturing dust and soil dust made low contributions to ambient PM₁₀.     

胶束强化超滤处理阿特拉津的研究

常规处理工艺并不能有效去除水中的环境内分泌干扰物质。研究采用十二烷基硫酸钠(SDS)为表面活性剂对阿特拉津进行增溶,并采用聚砜超滤膜和SDS胶束强化超滤处理阿特拉津。考察了SDS浓度、操作压力、无机盐、β-环糊精和烷基多苷(APG)等因素对工艺的影响。结果表明,胶束强化超滤对阿特拉津的去除率可达80%以上,无机盐、β-环糊精、APG和SDS的复配可以提高阿特拉津的去除率。     

Influence of fuel mass load, oxygen supply and burning rate on emission factor and size distribution of carbonaceous particulate matter from indoor corn straw burning

The uncertainty in emission estimation is strongly associated with the variation in emission factor (EF),which could be influenced by a variety of factors such as fuel properties,stove type,fire management and even methods used in measurements.The impacts of these factors are complicated and often interact with each other.Controlled burning experiments were conducted to investigate the influences of fuel mass load,air supply and burning rate on the emissions and size distributions of carbonaceous particulate matter (PM) from indoor corn straw burning in a cooking stove.The results showed that the EFs of PM (EFPM),organic carbon (EFOC) and elemental carbon (EFEC) were independent of the fuel mass load.The differences among them under different burning rates or air supply amounts were also found to be insignificant (p > 0.05) in the tested circumstances.PM from the indoor corn straw burning was dominated by fine PM with diameter less than 2.1 μm,contributing 86.4%±3.9% of the total.The size distribution of PM was influenced by the burning rate and air supply conditions.On average,EF PM,EF OC and EF EC for corn straw burned in a residential cooking stove were (3.84±1.02),(0.846±0.895) and (0.391±0.350) g/kg,respectively.EF PM,EF OC and EF EC were found to be positively correlated with each other (p < 0.05),but they were not significantly correlated with the EF of co-emitted CO,suggesting that special attention should be paid to the use of CO as a surrogate for other incomplete combustion pollutants.     

不同氮浓度冲击对颗粒污泥脱氮过程中N2 O产生量的影响

采用好氧-缺氧SBR污水生物处理系统,考察不同进水NH4+-N浓度冲击对同步硝化反硝化型颗粒污泥脱氮过中N2O的释放规律和脱氮效果的影响.结果表明,当进水NH4+-N浓度分别从稳定的30 mg·L-1突然提高到40、60和80 mg·L-1时,氨氮去除率从80.04%降至61.40%、39.65%和31.02%,但氨氮的去除量变化不大,都在25 mg·L-1左右;另外,N2O产生量受进水NH4+-N冲击较小,在4个不同的进水NH4+-N浓度下,典型周期N2O产生量分别为3.019、3.489、3.271和3.490 mg·m-3,而且N2O释放速率都在0.004 5 mg·(m3·min)-1左右.同步硝化反硝化型颗粒污泥系统的好氧阶段和缺氧阶段均有N2O产生.不同的NH4+-N浓度冲击下,同步硝化反硝化型颗粒污泥系统对NH4+-N的去除量没有变化,但由于进水NH4+-N浓度的提高引起系统脱氮率显著下降.     

Using sediment resuspension to immobilize sedimentary phosphorus

Environmental Science and Pollution Research - The response of the transformation of internal phosphorus (P) to resuspended sediment was investigated in the sediment-water system under different...     

The relationship between maternal perfluoroalkylated substances exposure and low birth weight of offspring: a systematic review and meta-analysis

Environmental Science and Pollution Research - Some studies have shown that maternal perfluoroalkylated substances (PFAS) exposure may be associated with low birth weight (LBW) of offspring. We...     

断路器欠压脱扣器抗冲击设计

主要应用于舰船等有冲击场合的断路器，其抗冲击性能要求很高。介绍了断路器欠压脱扣器在抗冲击方面的设计方法，此方法可以有效地削弱冲击力对欠压脱扣器的影响。