基于卫星数据的灰霾污染遥感监测方法及系统设计

以中分辨率成像光谱仪为例,建立了卫星遥感参数和空气污染指标之间的联系,提出了基于卫星遥感的气溶胶光学厚度数据获得灰霾指数和灰霾污染时空气质量指数(AQI)等级的方法和相关的监测系统设计。结合在华北地区的监测结果,可以看出卫星遥感可以较好地反映灰霾污染程度的变化,有助于发现可能的传输通道,获得宏观的灰霾空间分布状况。在研究时段内,与地面空气质量监测站相比,88%的卫星遥感监测结果误差不大于1个AQI等级,平均的AQI等级偏差为0.7级,并分析了卫星遥感与地面监测之间差异的原因。     

加强环境监测点位管理的思考——以江苏省“十二五”环境监测网络调整为例

基于江苏省"十二五"环境质量监测网络优化调整工作,指出监测点位设置和管理工作中存在的问题,讨论了点位优化调整的原则和思路,总结监测网络调整结果,并开展点位优化调整的成效分析,提出进一步优化监测网络设置的建议。     

太湖湖风指数阈值的计算

根据2012年8月17—23日的太湖湖风加密观测实验结果,将湖岸3个常规气象站和湖面2个浮标站观测的风速和气温资料代入经典的湖风指数公式,通过Fisher二级判别法和历史拟合率最大法确定了太湖湖风指数的阈值为3.0。该结论为研究太湖湖风的发生频率及其对蓝藻水华全湖输移的影响提供了理论依据。     

南京市臭氧、VOCs和PANs污染特征及变化趋势

对2013—2016年基于国家环境空气质量监测站以及省建大气多参数站所获取的南京市O_3、NO_2、CO、VOCs、PANs观测结果进行综合评价,结果表明:2016年南京市O_3第90百分位日最大8 h平均质量浓度比2013年上升33.3%,超标天数中O_3引起的超标占比增至32.0%。南京市区大气中非甲烷总烃冬季浓度高于夏季,含氧挥发性有机物则与之相反;在5—9月,含氧挥发性有机物组分在日变化过程中出现峰值的时间先后顺序依次为醚、醛、酮类,且O_3和过氧乙酰硝酸酯(PANs)生成存在有一定的线性关系。VOCs/NOx比值表明南京市处于VOCs控制区,因此对NO_2浓度下降不敏感,植物源挥发性有机物连续3年上升,夏季大气光化学反应活性未显著下降,这些现象是城市O_3浓度维持在较高水平的重要因素。     

TiO2光催化-微滤膜分离深度净化亚甲基蓝印染废水

采用悬浮式TiO2光催化膜反应器深度净化纺织工业园区含亚甲基蓝印染废水经生物处理二级出水,利用中空纤维微滤膜进行催化剂截留分离,研究催化剂投加量、运行时间、溶解氧、搅拌方式对出水水质及膜通量的影响。结果表明:光催化会消耗体系溶解氧,鼓风曝气搅拌可同时为系统供氧,优于机械搅拌;该耦合体系的催化剂最佳投加量为1 g/L,经光催化氧化-膜组合工艺处理后水质优于GB 4287-1992《纺织染整工业污染物排放标准》的I级标准,符合建设部颁布的《生活杂用水水质标准》(CJ/T 48-1999)。     

城市污水厂污泥化学调理深度脱水机理

城市污水厂剩余污泥脱水是当前实际生产中亟待解决的问题。考察了厦门市集美污水厂剩余污泥经FeCl3和CaO,投加量分别为污泥质量分数的0.5%～0.7%和1.0%～1.5%化学调理前后污泥粒度、形态及胞外聚合物(extracellular polymeric substances,EPS)的变化。结果表明,调理后污泥比阻降低86%,污泥颗粒之间细碎紧密,细菌表面变得粗糙,经板框压滤后含水率低于60%。由三维荧光光谱(three-dimensional emission and excitation matrixs,EEM)光谱分析可知,LB-EPS(loosely bound-EPS)同TB-EPS(Tightly bound-EPS)的荧光峰整体发生红移,出现位于IV区域的色氨酸类蛋白质荧光峰Ex/Em=313/380 nm。FeCl3和CaO的加入一方面破坏了污泥颗粒的细胞结构,使EPS大量溶出,细胞结合水变成表面吸附水;另一方面Fe3+和CaO水解,中和污泥负电荷,通过压缩双电层作用破坏污泥胶体颗粒的稳定,去除表面吸附水,大幅提高了污泥的脱水性能,利于进一步板框压滤脱水。     

硫化物对污水处理厂硝化菌活性的抑制作用

建于城市远郊区的污水处理厂由于长距离管道输送污水中通常含有一定浓度的硫化物。通过郊区和城区污水处理厂硝化菌最大比增长速率常数（μA）的测定和硫化物抑制实验研究了硫化物对硝化菌活性的影响。经测定,位于郊区的白龙港污水处理厂15、20和25℃下μA值分别为0.19 d-1、0.50 d-1和0.72 d-1,而15℃和20℃下位于市区的曲阳厂μA值分别为0.41 d-1和0.80 d-1。通过向曲阳厂污泥中加入硫化钠和氯化钠的实验发现,低浓度钠离子对硝化菌活性没有明显的抑制作用;而硫化物在曝气条件下直接与污泥接触对硝化菌活性几乎没有影响,但不曝气混合接触后再曝气则硝化菌μA值将下降50%左右。硫化物的抑制作用很可能是白龙港厂硝化菌μA值明显低于曲阳厂实测值和文献报道值的原因。     

曝气对生物促生剂修复城市黑臭河道水体的影响

在实验室条件下研究了曝气对生物促生剂修复城市黑臭河道水体效果的影响,并通过控制曝气时间及强度考察处理效果以确定曝气方式和曝气量。结果表明：在生物促生剂修复城市河道黑臭水体过程中使用曝气协同作用可大大增强生物促生剂的修复作用,加快修复速度。使用间歇曝气协同生物促生剂作用时效果与连续曝气相近,且可以降低运行成本。实验60d后,上覆水COD、NH3-N和TP去除率分别达46．8％、98．7％和73．3％,上覆水pH由7．61提高至7．92;底泥削减达5．49cm,底泥有机质削减率达10．5％。     

Control strategies of atmospheric mercury emissions from coal-fired power plants in China

Atmospheric mercury (Hg) emission from coal is one of the primary sources of anthropogenic discharge and pollution. China is one of the few countries in the world whose coal consumption constitutes about 70% of total primary energy, and over half of coals are burned directly for electricity generation. Atmospheric emissions of Hg and its speciation from coal-fired power plants are of great concern owing to their negative impacts on regional human health and ecosystem risks, as well as long-distance transport. In this paper, recent trends of atmospheric Hg emissions and its species split from coal-fired power plants in China during the period of 2000-2007 are evaluated, by integrating each plant's coal consumption and emission factors, which are classified by different subcategories of boilers, particulate matter (PM) and sulfur dioxide (SO2) control devices. Our results show that the total Hg emissions from coal-fired power plants have begun to decrease from the peak value of 139.19 t in 2005 to 134.55 t in 2007, though coal consumption growing steadily from 1213.8 to 1532.4 Mt, which can be mainly attributed to the co-benefit Hg reduction by electrostatic precipitators/fabric filters (ESPs/FFs) and wet flue gas desulfurization (WFGD), especially the sharp growth in installation of WFGD both in the new and existing power plants since 2005. In the coming 12th five-year-plan, more and more plants will be mandated to install De-NO(x) (nitrogen oxides) systems (mainly selective catalytic reduction [SCR] and selective noncatalytic reduction [SNCR]) for minimizing NO(x) emission, thus the specific Hg emission rate per ton of coal will decline further owing to the much higher co-benefit removal efficiency by the combination of SCR + ESPs/FFs + WFGD systems. Consequently, SCR + ESPs/FFs + WFGD configuration will be the main path to abate Hg discharge from coal-fired power plants in China in the near future. However advanced specific Hg removal technologies are necessary for further reduction of elemental Hg discharge in the long-term.     

Bioaccessibility of arsenic in various types of rice in an in vitro gastrointestinal fluid system

Rice can be a major contributor to dietary arsenic exposure because of the relatively high total arsenic concentration compared to other grains, especially for people whose main staple is rice. This study employed in vitro gastrointestinal fluid digestion to determine bioaccessible or gastrointestinal fluid extractable arsenic concentration in rice. Thirty-one rice samples, of which 60 % were grown in the United States, were purchased from food stores in New York City. Total arsenic concentrations in these samples ranged from 0.090 ± 0.004 to 0.85 ± 0.03 mg/kg with a mean value of 0.275 ± 0.161 mg/kg (n = 31). Rice samples with relatively high total arsenic (>0.20 mg/kg, n = 18) were treated by in vitro artificial gastrointestinal fluid digestion, and the extractable arsenic ranged from 53 % to 102 %. The bioaccessibility of arsenic in rice decreases in the general order of extra long grain, long grain, long grain parboiled, to brown rices.