美国炼油厂循环冷却水处理与污水回用现状

介绍了美国炼油厂循环冷却水系统的水质指标及常用的水质稳定技术,简述了美国炼油厂污水回用于循环冷却水的水源和水质要求,论述了市政污水回用的深度处理技术,分析了回用水对炼油厂循环冷却水系统的影响及相应的水处理工艺的调整方法,为我国炼油厂循环冷却水处理及污水回用提供借鉴。     

丹江口水库蓄水后汉江中下游水文时空变化的#br# 定量评估及其生态影响

采用变化范围法（RVA）定量研究了丹江口水库蓄水后汉江中下游水文情势的时空变化,评估出汉江干流变化度最大的江段和水文特征指标类别,分析了其对应的生态影响,并针对汉江流域的四大家鱼和水华问题进行了敏感水文指标的变化度分析。结果显示:丹江口大坝蓄水后,汉江下游河道流量是中变化度占主导,比例范围为47～63%;水位是高变化度占主导,襄阳站和皇庄站高变化度的水文指标所占比例远大于其它站点,依次为53% 和75%,各站水位较蓄水前下降了1～2 m。黄家港站高/低流量脉冲出现的频率减少（变化度为-0.49和 -0.62）,且持续的时间变短（变化度为-0.87和 -0.74）。皇庄站和襄阳站流量和水位的月均值和极值较蓄水前减少,逆转次数在高RVA范围内较蓄水前增加（变化度为1.82）。四大家鱼产卵的敏感水文指标出现频率较蓄水前减少,且为中高变化度。下游河道枯水期流量和水位减小,增加了水华发生几率。     

再生水回用循环冷却系统药剂HJ-01阻垢机理

针对再生水回用于循环冷却系统中引起的结垢问题,进行了碳酸钙沉积实验和旋转挂片腐蚀实验,对所得的结垢产物的微观形态、元素组成以及化合物构成,分别采用扫描电子显微镜、X射线能谱仪和X射线衍射仪进行分析,探究复配药剂HJ-01在阻垢过程中的机理,并深入分析该药剂结构中官能团的阻垢特性。实验结果表明,药剂HJ-01可以通过在挂片表面形成具有保护作用的薄膜而阻垢,其阻垢机理包括晶格畸变、螯合增溶和分散作用;其中膦酸基(—PO3H2)和羟基(—OH)官能团引起晶格畸变作用;羧基(—COOH)官能团引起螯合增溶作用;而阻垢剂中的链状结构导致分散作用的产生。     

影响旁路净化含油循环水达标时间的主要因素

基于循环冷却水旁路净化含油水的模拟装置,研究了旁路流速、各次料水比、旁路吸附塔填料换料时间间隔、吸附塔填料填装形式、系统温度对系统含油水浓度达标时间的影响.结果表明:净化达标时间随旁路流速的增加呈先减少后增加趋势,旁路流速为1.68 ×10-3 m/s时,净化达标时间最短;选择适当的各次料水比1/2 400,保证较短的净化达标时间和较低的经济成本;换料时间间隔为△tn+1=1.2nh时,较其他方式更有效合理;吸油填料的填装形式为混合式,系统运行温度为35℃时,净化达标时间最短.     

长江上游大型水库群对宜昌站水文情势影响分析

近年来,长江上游已建成一批大型水库,其运行调度必然会对下游的径流产生影响。水文变化指标法(IHA)和水文变化幅度法(RVA)是以水流的量、时间、频率、延时和变化率5种基本特征为基础,对建坝前后的河道水文情势变化进行定量分析的方法。根据长江流域大型水库群建设的实际情况,利用Mann-Kendall秩次相关检验法划分了宜昌站建库前后的流量序列,用来评估长江上游大型水库群对宜昌站水文情势的改变情况。M-K相关检验发现,宜昌站的年最小流量已经在2000年发生了显著性地变化;IHA和RVA分析成果表明,宜昌站的水文情势已经发生了中等程度的改变,主要是与小流量相关的一些因子,如1~3月平均流量、最小流量六个因子、低脉冲发生次数及持续时间等;随着以三峡水库为核心的上游大型水库群建成并投入运行,未来长江下游河道径流还将发生进一步的改变。     

偶氮二甲酰胺发泡剂清洁生产评价模型

提出了针对不同工艺的偶氮二甲酰胺（ADC）发泡剂生产企业的清洁生产综合评价方案。利用逐层序关系分析法确定各指标的影响因子,采用极差标准化法对正逆向指标数据进行初步处理,使用主成分分析法对ADC发泡剂生产企业进行排名。该研究为ADC发泡剂清洁生产评价提供了一个更加客观和精确的方案。     

Determination of indicator polychlorinated biphenyls (PCBs) by gas chromatography–electron capture detector

An effective method for determination of indicator polychlorinated biphenyls (PCBs) has been validated using gas chromatography (GC) equipped with electron capture detector (ECD). The GC–ECD method was validated by determining the linear range (working range) for determination of the compounds, minimum detectable quantities (MDQ), the precision and accuracy of the method for the analysis of the compounds. MDQ obtained for the compounds ranges from 0.0005 to 0.002 ng. Indeed the method was found to be more sensitive as the number of chlorine atoms attached to the biphenyl increases. The precision and accuracy of the GC method validated ranges from 2.4% to 14.5% and −7.0% to 14.6% respectively. Coefficient of variation associated with the repeatability of the retention times and corresponding peak areas was found to be 0.0001–0.0007 for the retention times and 0.0014–0.059 for the peak areas. Percentage recoveries for the compounds were in the range of 95.7–101.0%. The validated method was then applied to determine levels of indicator PCBs in sediments sampled from eleven sampling points along the Lake Bosuntwi in Ghana and the highest PCB load of 19.17 ng g⁻¹ was recorded at Pipie No. 2. PCB 52 and PCB 101 were found to be the most ubiquitous indicator PCBs in the study area, both with 90.91% occurrence.     

铁路交通噪声对鸟类生态环境的影响预测评价

由于鸟类的听觉频率范围与人类不同,以往基于A计权声压级的噪声测量方法,用于鸟类声环境的监测评价并不准确。以广东省江门市新会区“小鸟天堂”风景名胜区为例,开展铁路交通噪声对鸟类生态环境的影响研究。首先,通过实地调查,对鸟类生态区的多个监测点进行声环境线性频谱测量;其次,根据新茂铁路新会段的规划布局,采用模式预测法计算铁路运行期间在监测点产生的交通噪声频谱,并与铁路运行前实地测量的现状频谱叠加;在此基础上,进一步探讨铁路交通噪声对鸟类生态区声环境的影响以及预防措施。研究结果表明,列车运行时在鸟类良好听觉频率范围的噪声增量可达10~30dB,将严重影响鸟类声环境;当采取全封闭声屏障防护措施之后,可有效降低“小鸟天堂”景区范围的噪声。     

城市二级处理后污水直接回用作工业循环冷却水的阻垢研究

采用碳酸盐沉积法及动态模拟试验研究了将城市污水处理厂二级出水直接回用作工业循环冷却水时,污水中的悬浮物、COD、浓缩倍数等因素对系统的结垢和药剂阻垢效率的影响。     

Region-wide retreats from lower elevations of range-restricted birds across the Northern Andes

Local studies show upslope shifts in the distribution of tropical birds in response to warming temperatures. Unanswered is whether these upward shifts occur regionally across many species. We considered a nearly 2000-km length of the Northern Andes, where deforestation, temperature, and extreme weather events have increased during the past decades. Range-restricted bird species are particularly vulnerable to such events and occur in exceptionally high numbers in this region. Using abundant crowd-sourced data from the Cornell Lab of Ornithology database, eBird, and the Global Biodiversity Information Facility, we documented distributions of nearly 200 such species. We examined whether species shifted their elevational ranges over time by comparing observed versus expected occurrences below a low elevational threshold and above a high elevational threshold for 2 periods: before and after 2005. We predicted fewer observations at lower elevations (those below the threshold) and more at upper elevations (those above the threshold) after 2005. We also tested for deforestation effects at lower elevations within each species’ distribution ranges. We compared relative forest loss with the differences between observed and expected occurrences across the elevational range. Species’ retreats from lower elevations were ubiquitous and involved a 23–40% decline in prevalence at the lowest elevations. Increases at higher elevations were not consistent. The retreats occurred across a broad spectrum of species, from predominantly lowland to predominantly highland. Because deforestation showed no relationship with species retreats, we contend that a warming climate is the most parsimonious explanation for such shifts.