典型炼化企业温室气体甲烷排放特征

温室气体排放是造成全球变暖和气候恶化的重要根源.甲烷是仅次于二氧化碳的温室气体组分.石油加工过程是潜在的甲烷排放源.本文以我国广西某炼化企业为样本,通过现场采样和离线分析的方法,识别出炼化企业潜在的甲烷排放源,核算了不同排放源的甲烷排放量,分析了炼化企业的甲烷排放特征.研究表明,甲烷是炼化企业排放废气中的重要成分;烟气、污水收集和处理系统、储罐和油品装卸过程等均是重要的甲烷排放源项,其中烟气和储罐对甲烷排放总量贡献占比超过70%;不同源项甲烷排放特征各异,油品装载过程产生废气甲烷浓度最高;污水处理过程废气的甲烷浓度主要受常减压装置污水影响;该炼化企业每万吨原油对应的甲烷排放速率估算值为72.6 kg.     

郴州市大气PM2.5碳组分污染特征及其来源分析

为研究郴州市PM_2.5中碳组分的污染特征及来源,于2016年7月-2017年4月分4个季度典型时段采集郴州市环境大气中的PM_2.5,测定了样品中OC（有机碳）和EC（元素碳）的质量浓度,对碳气溶胶污染水平、时空分布、SOC（二次有机碳）以及OC和EC相关性等特征进行了分析,并分析了碳组分的来源.结果表明:郴州市ρ（PM_2.5）年均值为（40.2±19.0）μg/m3,ρ（OC）、ρ（EC）占比分别为15.7%和7.2%;ρ（OC）与ρ（EC）相关性分析显示二者来源较为一致,但春季、夏季差异相对较大;ρ（SOC）全年估算值为1.84 μg/m3,占ρ（OC）的29.11%,夏季较高的温度和较低的相对湿度导致夏季ρ（SOC）的估算偏低.结合碳组分丰度分析、PCA（主成分分析）和PMF（正矩阵因子分解分析）结果发现,燃煤/道路尘、机动车排放和生物质燃烧对PM_2.5中TC（总碳）的影响最为明显,贡献率分别为49.25%~56.71%、19.79%~25.36%和9.35%~13.69%.反向轨迹聚类结果显示,广东珠三角区域的汽油车排放、道路尘和生物质燃烧对郴州市PM_2.5中碳组分有较大的影响,而燃煤和柴油车的贡献主要来源于本地.研究显示,郴州市PM_2.5中碳组分污染较为严重,应重点加强本地燃煤和柴油车的控制.      

高纯二聚酸清洁生产技术分析

以一个利用高真空三级分子蒸馏技术生产高纯二聚酸的大型新建项目为例，对其原料、产品、工艺和设备进行了分析。以从棉籽油下脚料中提取的粗二聚酸为原料，自主开发了高真空三级分子蒸馏技术并改进了设备及控制条件，使二聚酸的纯度最高可达98％，水、蒸汽及能源的消耗均比原工艺有所下降。对在高纯二聚酸生产中推行清洁生产提出了建议和措施。     

基于GIS的土地利用类型分形维数及稳定性研究——以滇池流域为例

应用GIS技术及分形理论,以云南省滇池流域为研究区,将土地利用类型划分为5类：耕地、林地、草地、水域及城乡工矿居民用地,并进行各土地利用类型图斑分形维数分析。结果表明：土地利用类型的分布具有分形结构,各土地利用类型分维值介于1.09～1.35之间,总分维值1.146。根据分维值对各土地利用类型稳定性排序：林地〉草地〉耕地〉水域〉城乡工矿居民用地。若不考虑水域影响,稳定性指数均介于0.2～0.5之间的土地利用类型面积占研究区土地总面积的80.18%,总体稳定性良好。说明在人为规划影响下,滇池流域土地利用总的发展比较稳定,人为因素、人工措施的实施比较合理。分维值能较好反映各土地利用类型复杂程度及稳定性。     

基于DEM的太湖流域水文特征提取

文章选取太湖流域作为研究对象,采用1：25万中比例尺DEM作为基础数据,应用ESRI公司开发的ArcGIS地理信息系统软件进行流域水文特征提取,得到了研究区域水流流向、汇流栅格生成、河网水系、子流域边界等流域特征信息,经与标准河流水系特征对照,认为基于DEM提取的太湖流域水文特征信息是合理的,可作为基础信息,为太湖流域生态环境治理实践及理论研究提供数据支撑。     

Immobilization of NZVI in polydopamine surface-modified biochar for adsorption and degradation of tetracycline in aqueous solution

Polydopamine/NZVI@biochar composite (PDA/NZVI@BC) with high removal efficiency of tetracycline (TC) in aqueous solutions was successfully synthesized. The resultant composite demonstrated high reactivity, excellent stability and reusability over the reaction course. Such excellent performance can be attributed to the presence of the huge surface area on biochar (BC), which could enhance NZVI dispersion and prolong its longevity. The carbonyl group contained on the surface of biochar could combine with the amino group on polydopamine(PDA). The hydroxyl groups in PDA is able to enhance the dispersion and loading of NZVI on BC. Being modified by PDA, the hydrophilicity of biochar was improved. Among BC, pristine NZVI and PDA/NZVI@BC, PDA/ NZVI@BC exhibited the highest activity for removal of TC. Compared with NZVI, the removal efficiency of TC could be increased by 55.9% by using PDA/NZVI@BC under the same conditions. The optimal modification time of PDA was 8h, and the ratio of NZVI to BC was 1:2. In addition, the possible degradation mechanism of TC was proposed, which was based on the analysis of degraded products by LC-MS. Different important factors impacting on TC removal (including mass ratio of NZVI to BC/PDA, initial concentration, pH value and the initial temperature of the solution) were investigated as well. Overall, this study provides a promising alternative material and environmental pollution management option for antibiotic wastewater treatment.

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人工土壤渗滤对颗粒COD的吸附及堵塞

生活污水中颗粒COD占到总COD的30%~60%,砂滤试验证实,非生物参与的单纯过滤仅能去除总COD的20%~35%。人工土壤渗滤对颗粒COD的吸附是通过系统介质表层的快速接触-吸附完成的,通常80%以上吸附量集中在表层20 cm之内。对颗粒COD的吸附是人工土壤渗滤系统堵塞的主要原因,微生物增长量占到系统孔隙率的3.7%~5.3%。通过对系统入渗及恢复试验,得到系统干湿交替运行的合适配搭,对人工土壤渗滤防堵塞和长期稳定运行提供了有益探索。     

渤海环流对近岸海域无机氮分布特征的影响

基于2017年渤海近岸海域无机氮监测数据和HYCOM数值模拟结果,分析了渤海环流对无机氮污染分布特征的影响,结果表明渤海无机氮的空间分布特征与其环流结构密切相关:受渤海环流的影响,在春、夏、秋季,无机氮含量高值区呈现不同的强度和范围;在辽东湾,与春季相比,夏季环流结构与春季相反、速度大于春季,盘锦、营口近岸海域夏季无机氮污染范围缩小、含量降低,在锦州近岸海域亦出现高值;在渤海湾、莱州湾,与春季相比,夏季和秋季无机氮含量高值区范围缩小,无机氮含量等值线均随环流向高值中心扩展。     

添加剩余活性污泥无害化处理含油钻屑

采用剩余活性污泥对废弃含油钻屑进行无害化处理。考察了加入剩余活性污泥后混合物料中微生物浓度、碱解氮含量、有效磷含量、总石油烃(TPH)含量和组分的变化,并对降解后混合物料的生物毒性进行了评价。实验结果表明:加入剩余活性污泥后,总细菌浓度保持在较高水平;碱解氮含量逐渐减少后保持稳定,有效磷含量在一定范围内波动,整体略有增加;剩余活性污泥的加入量为20%～60%(w)时, TPH去除率均达到74%以上,远高于未添加剩余活性污泥的对照组(28.8%);剩余活性污泥的添加能有效促进微生物对含油钻屑中TPH的降解及氮元素的转化,添加50%(w)以上的剩余活性污泥能使处理后含油钻屑的生物毒性更低,更有利于含油钻屑的无害化处理。     

Sorption of chlorimuron-ethyl on montmorillonite clays: effects of exchangeable cations,pH, and ionic strength

Sorption interaction of chlorimuron-ethyl with montmorillonite clays was investigated under varied types of exchangeable cation, pH, and ionic strength conditions. Chlorimuron-ethyl sorption on bentonites exhibited pronounced cation dependency, and the sorption ability increased as the sequence Ca²⁺- < Na⁺- < Al³⁺- < Fe³⁺-bentonite, due to different sorption mechanisms, whereas the cation dependency was influenced by the clay type and much weaker for montmorillonites. The decrease of pH at the range of 4.0–6.0 prominently increased sorption of chlorimuron-ethyl on all cation-exchanged montmorillonite clays, and nearly a neglected sorption (about 2 %) can be observed at pH over 7.0. In the presence of CaCl₂, sorption of chlorimuron-ethyl on Fe³⁺-bentonite was promoted because of complexion of Ca²⁺ and the surface of Fe³⁺-bentonite. However, as the concentration of CaCl₂ increased, chlorimuron-ethyl sorption on Ca²⁺- and Fe³⁺-exchanged bentonite decreased, suggesting that Ca bridging was not the prevailing mechanism for sorption of chlorimuron-ethyl on these clays. Furthermore, chlorimuron-ethyl sorption was relatively sensitive to pH, and the change of pH may obscure effect of other factors on the sorption, so it was quite necessary to control pH at a constant value when the effect of other factor was being studied.