地理信息系统在累积影响评价中的应用

累积影响评价是在可持续发展目标要求下环境影响评价的一种新类型,但目前进行累积影响评价的方法和工具仍较缺乏。文章分析了利用地理信息系统进行累积影响评价的能力,结果表明：地理信息系统能改善对发展行为和环境状况的监测和跟踪,能较好地分析环境影响的时、空累积特征,是进行累积影响评价的有效工具;但是,其对环境影响累积过程的本质考虑有限,需要与能反映累积过程的子模式相结合。     

Effects of sulfur on variations in the chemical speciation of heavy metals from fly ash glass

● A higher sulfur content reduced the curing rate of Cr in glass. ● Depolymerization increased the amounts of heavy metals in the carbonate bound state. ● Reducing the CaO/SiO₂ ratio increased the proportion of stable heavy metals. This work designed a new CaO-Al₂O₃-SiO₂-SO₃ glass for the immobilization of multiple heavy metals found in dechlorinated fly ash having high amounts of calcium and sulfur. Increasing the (CaO + SO₃)/SiO₂ mass ratio (M(CS/S)) from 0.28 to 0.85 was found to lower the proportions of Mn, Ni and Zn in an unstable state, while an M(CS/S) ratio of 0.51 gave the lowest proportions of unstable Cr and Pb. Decreasing the degree of polymerization of the glassy network increased the proportions of Mn, Cr, Ni, Pb and Zn in the carbonate bound state. The leaching out of metals in this state was the primary cause of degradation of Q³ structural units in the glassy network. The amount of Mn in the iron-manganese oxide bound state was increased by increasing the number of Q² units in the silicate network. Decreasing the CaO/SiO₂ mass ratio (M(C/S)) raised the proportions of Mn, Ni and Zn in the unstable state. An M(C/S) value of 0.43 lowered the proportions of unstable Cr and Pb. A principal components analysis determined that the leaching of toxic heavy metals from the glass was primarily related to the proportions of these metals in the unstable state while there were no evident correlations between leaching and the proportions in stable states.     

真空紫外灯动态降解空气中低浓度甲醛的研究

以集中空调中处理室内可挥发性有机物(VOCs)为应用背景,搭建了试验台.实验研究了真空紫外灯(主波长254 nm,185 nm)降解甲醛的影响因素以及产生O3的情况.研究表明,在产生的O3浓度低于室内空气质量标准(0.16mg/m3)的情况下,真空紫外灯也能够高效地降解空气中低浓度甲醛(＜1 mg/m3);甲醛降解率与反应器空气流速及甲醛初始浓度成反比;降解速率与甲醛初始浓度成正比,与反应器空气的流速成反比;绝对湿度对真空紫外灯降解甲醛有一定的影响;反应器空间大小对甲醛降解影响比较显著.应用于集中空调系统净化室内空气中VOCs,取得了很好的效果.     

The excessive enrichment of trace elements in migratory and breeding red-crowned cranes (Grus japonensis) in China

Environmental Science and Pollution Research - The excessive enrichment of trace elements, such as Pb and Cd, from food may contribute to the decline of migratory red-crowned cranes (Grus...     

基于动态聚类分析和盲数理论的综合营养状态指数评价模型

考虑到常用水质富营养化评价模型的单一、确定性缺点,尝试将动态聚类分析与盲数耦合理论引入水环境富营养化评价领域,建立了改进的综合营养状态指数评价模型,最后借助克里格插值法对评价结果的可信度进行空间可视化表征。利用改进模型对2009年洞庭湖区域的水环境空间的富营养化状况进行了评价,结果表明,东洞庭湖、扁山、鹿角富营养化程度相对严重,隶属于富营养化的可信度分别达到了0.5444、0.5318和0.5260。与确定性评价模型对比分析表明,所建改进模型更充分地考虑到被观察个体的差异,集成了更全面的样本信息,并可同时计算出了各采样点综合营养状态指数的区间数与其相对应的可信度水平,从而有效地提高了评价模型的可分辨性。     

污泥厌氧消化的人工神经网络模型

基于污泥固体停留时间(SRT)为20 d的污泥中温厌氧消化实验,建立一个3层BP神经网络,以前1～20 d的进泥挥发性悬浮固体(VSS)、当天消化罐pH值和碱度共22个参数为输入,预测污泥消化系统日产气量,结果表明,网络具有良好的学习能力、泛化能力和辨识能力,能够较为准确地预测出系统日产气量.此外,根据进泥VSS不同,利用网络预测能力,调节pH值和碱度到合适的值,系统日产气量有明显提高,进一步证明了网络具有良好的预测能力和实用性.     

330MW机组锅炉后墙水平刚性梁振动原因分析及处理

大唐略阳发电有限责任公司1 018t/h锅炉的锅炉平台、扶梯、刚性梁有非常明显的振动,需及时处理,以免长期振动造成对锅炉设备的破坏.通过对锅炉振动原因的分析,从3个方面进行治理,取得了较好效果,对于同类型锅炉的振动具有借鉴作用.     

螯合沉淀法处理电镀废水的工业实践

介绍了一个采用螯合沉淀法处理电镀废水的典型工业实例.在工业装置上,进行了氢氧化钠、硫化钠和DT-CR去除重金属离子效果的对比,讨论了DTCR的加入量与处理成本的关系和pH值对DTCR用量的影响.结果表明,将废水的pH值调至8.0～8.5后再加DTCR,可以使DTCR的使用量最少,处理成本最低;此法对重金属离子的去除效果远优于传统化学沉淀法.     

具有可见光活性的氮掺杂TiO_2光催化剂的制备及光催化性能

采用浓氨水处理Ti(SO4)2溶液,然后经过滤、干燥、煅烧制备了一种氮掺杂TiO2光催化剂TiO2-XNX,其最佳煅烧温度为400℃。对该光催化剂的XRD谱图进行分析,结果表明,TiO2-XNX的晶型为锐钛矿相。紫外—可见吸收光谱表明,该光催化剂在可见光区具有明显的吸收。甲基橙溶液的降解实验结果表明,制备的TiO2-XNX光催化剂具有可见光(波长λ400nm)活性。     

Variation of spatio-temporal distribution of on-road vehicle emissions based on real-time RFID data

High-resolution vehicular emissions inventories are important for managing vehicular pollution and improving urban air quality. This study developed a vehicular emission inventory with high spatio-temporal resolution in the main urban area of Chongqing, based on real-time traffic data from 820 RFID detectors covering 454 roads, and the differences in spatio-temporal emission characteristics between inner and outer districts were analysed. The result showed that the daily vehicular emission intensities of CO, hydrocarbons, PM_2.5, PM₁₀, and NOx were 30.24, 3.83, 0.18, 0.20, and 8.65 kg/km per day, respectively, in the study area during 2018. The pollutants emission intensities in inner district were higher than those in outer district. Light passenger cars (LPCs) were the main contributors of all-day CO emissions in the inner and outer districts, from which the contributors of NOx emissions were different. Diesel and natural gas buses were major contributors of daytime NOx emissions in inner districts, accounting for 40.40%, but buses and heavy duty trucks (HDTs) were major contributors in outer districts. At nighttime, due to the lifting of truck restrictions and suspension of buses, HDTs become the main NOx contributor in both inner and outer districts, and its three NOx emission peak hours were found, which are different to the peak hours of total NOx emission by all vehicles. Unlike most other cities, bridges and connecting channels are always emission hotspots due to long-time traffic congestion. This knowledge will help fully understand vehicular emissions characteristics and is useful for policymakers to design precise prevention and control measures.