Boiler briquette coal versus raw coal: Part I--Stack gas emissions

Stack gas emissions were characterized for a steam-generating boiler commonly used in China. The boiler was tested when fired with a newly formulated boiler briquette coal (BB-coal) and when fired with conventional raw coal (R-coal). The stack gas emissions were analyzed to determine emission rates and emission factors and to develop chemical source profiles. A dilution source sampling system was used to collect PM on both Teflon membrane filters and quartz fiber filters. The Teflon filters were analyzed gravimetrically for PM10 and PM2.5 mass concentrations and by X-ray fluorescence (XRF) for trace elements. The quartz fiber filters were analyzed for organic carbon (OC) and elemental carbon (EC) using a thermal/optical reflectance technique. Sulfur dioxide was measured using the standard wet chemistry method. Carbon monoxide was measured using an Orsat combustion analyzer. The emission rates of the R-coal combustion (in kg/hr), determined using the measured stack gas concentrations and the stack gas emission rates, were 0.74 for PM10, 0.38 for PM2.5, 20.7 for SO2, and 6.8 for CO, while those of the BB-coal combustion were 0.95 for PM10, 0.30 for PM2.5, 7.5 for SO2, and 5.3 for CO. The fuel-mass-based emission factors (in g/kg) of the R-coal, determined using the emission rates and the fuel burn rates, were 1.68 for PM10, 0.87 for PM2.5, 46.7 for SO2, and 15 for CO, while those of the BB-coal were 2.51 for PM10, 0.79 for PM2.5, 19.9 for SO2, and 14 for CO. The task-based emission factors (in g/ton steam generated) of the R-coal, determined using the fuel-mass-based emission factors and the coal/steam conversion factors, were 0.23 for PM10, 0.12 for PM2.5, 6.4 for SO2, and 2.0 for CO, while those of the BB-coal were 0.30 for PM10, 0.094 for PM2.5, 2.4 for SO2, and 1.7 for CO. PM10 and PM2.5 elemental compositions are also presented for both types of coal tested in the study.     

电化学法去除有机污染物机理研究进展

电化学方法因其所具有的多功能性、操作简单、易于自动化并且具有环境兼容性等特点而倍受人们重视。近年来 ,国内外研究者对该方法在水处理中的应用进行了广泛的研究 ,并对有机污染物电化学降解机理提出了不同观点 ,本文对这些观点进行了分类 ,并对其中的主要观点进行论述     

中国环境税的研究与实践

阐述了国外（尤其是OECD国家）环境税的发展趋势，总结了我国环境税的研究和实践经验，指出中国目前还没有真正的环境税，只有几个与环境和资源有关的税种；政府和公众对环境保护认识的提高、环境问题的严重性以及环保投入的加大，将促使中国实施真正的环境税。     

珠江三角洲干线公路夏季臭氧污染特征

基于国家干线公路交通量信息,运用GIS的路网线性参考系统,计算珠三角地区夏季NO_x和VOCs排放量,使用最大增量反应活性（MIR）和经验公式,分别估算VOCs和NO_x的O₃生成及其强度的空间分布特征.结果表明,夏季VOCs的排放量占比总体上与各类型车辆数占比一致,而汽油车的NO_x排放量占比与车辆数差异较大;VOCs排放的分布与NO_x基本相似,广州市是NO_x和VOCs排放量最高的城市,珠海、中山和江门3个城市的排放量较小;NO_x的O₃生成总量与生成能力成反比,所有车型中烯烃和芳香烃对O₃生成贡献率都是最大的,而排放量较大的烷烃生成O₃量最低;路网密度大的广州市、深圳市,汽车排放的NO_x和VOCs量相对较高,其产生的O₃浓度也较高,对于路网密度较小的城市（如珠海市）,其O₃污染主要以交通干线为中心,向外扩散,O₃生成量较小.     

海洋牧场多水层溶解氧在线监测系统的构建及应用

为满足海洋牧场养殖区域多水层溶解氧（dissolved oxygen,DO）含量实时、在线、连续监测的需求,本文设计了一种剖面DO在线监测系统,系统集成自主研发的光学DO传感器,设计了链式DO剖面测量结构,开发了基于STM32单片机的数据采集与控制系统,通过无线传输模块与远程监控中心通信对接,实现了海洋牧场多水层DO监测数据的实时传输与可视化显示,方便用户查看当前海水DO及温度变化状况、历史数据及变化趋势。性能测试表明,本系统DO探头漂移可控制在3%范围内,整套系统的稳定性好、可靠性高。2016年至2018年,本系统在山东烟台的东方海洋云溪牧场进行了应用示范。观测数据显示:DO与温度表现出相似的变化规律,即表层>中层>底层;表层水DO浓度较高且变化幅度较小,中层海水DO变化幅度明显高于表层和底层,底层海水在未有明显的垂直混合作用下,DO呈持续走低趋势。观测期间,2016年和2017年海洋牧场底层海水均出现了长达18 d以上的低氧现象,且测试数据的时间序列变化趋势与天气变化相吻合,为海洋牧场的养殖企业提供了预警预报,减少了低氧灾害所带来的经济损失。     

Water uptake of multicomponent organic mixtures and their influence on hygroscopicity of inorganic salts

The hygroscopic behaviors of atmospherically relevant multicomponent water soluble organic compounds(WSOCs) and their effects on ammonium sulfate(AS) and sodium chloride were investigated using a hygroscopicity tandem differential mobility analyzer(HTDMA) in the relative humidity(RH) range of 5%–90%. The measured hygroscopic growth was compared with predictions from the Extended-Aerosol Inorganics Model(E-AIM) and Zdanovskii–Stokes–Robinson(ZSR) method. The equal mass multicomponent WSOCs mixture containing levoglucosan, succinic acid, phthalic acid and humic acid showed gradual water uptake without obvious phase change over the whole RH range. It was found that the organic content played an important role in the water uptake of mixed particles.When organic content was dominant in the mixture(75%), the measured hygroscopic growth was higher than predictions from the E-AIM or ZSR relation, especially under high RH conditions. For mass fractions of organics not larger than 50%, the hygroscopic growth of mixtures was in good agreement with model predictions. The influence of interactions between inorganic and organic components on the hygroscopicity of mixed particles was related to the salt type and organic content. These results could contribute to understanding of the hygroscopic behaviors of multicomponent aerosol particles.     

陕西省生态承载力供需平衡研究

陕西省经济发展主要依赖矿产资源的开发,尤其是煤炭资源的开发,随着全省经济的快速增长,生态环境问题也逐渐凸显,这一矛盾越来越引起人们的重视.为揭示陕西省生态环境破坏现状及生态环境承载能力,利用生态足迹理论,定量分析了陕西省生态承载能力及可利用空间.经过计算,2014年全省人均生态足迹1.3403 hm2,人均生态承载力1.9286 hm2,可利用人均生态承载力0.3569 hm2.结果表明,陕西省生态承载整体还有盈余,但草地、茶园和化石燃料用地均出现生态赤字,最后分析了产生生态赤字的原因.     

Toughening of Polyvinyl Alcohol Hydrogel Through Co-Crosslinking and its Wastewater Treatment Performance by Immobilizing with Microorganism

In order to improve the hydraulic impact resistance of the polyvinyl alcohol (PVA) hydrogel as microorganism immobilization carrier and meet the requirements of long-time aeration of sewage treatment, the toughening PVA hydrogel beads were prepared by co-crosslinking with polyoxypropylene triol (PPG) through the boric acid (H₃BO₃)-chemical crosslinking method. It was found that PPG could increase the consumption of H₃BO₃, participated and accelerated the crosslinking reaction of PVA, and the pore size of the surface layer and core layer of the hydrogel beads can be controlled. With increasing PPG content, the shear storage modulus (G’) and the effective network density (ν_e) increased first, reached maximum in presence of 2 wt% PPG, and decreased afterwards. A relatively low content of PPG could promote the formation of relatively uniform and dense network structure in PVA hydrogel, resulting in an improvement of the mechanical property and long-term hydraulic stability of the gel beads. By addition of PPG, the capillary water absorption capacity of PVA hydrogel can be enhanced and the high permeability can be kept well. When applying in waste water treatment, the value of the oxygen uptake rate (OUR) and COD removal rate of the PVA hydrogel immobilized with activated sludge had no obvious difference with addition of PPG, and a high microbial activity can be maintained.     

Nitrogen use efficiencies in Chinese agricultural systems and implications for food security and environmental protection

Regional Environmental Change - Nitrogen (N) use efficiency (NUE) is an important indicator to evaluate the performance of N use in agricultural systems. Understanding changes in NUE is crucial to...