中国淘汰滴滴涕的环境影响分析

目前中国仍在生产滴滴涕(DDT),并以其为原料生产三氯杀螨醇作为杀虫剂使用.为评价淘汰DDT对于中国生态环境的影响,采用情景分析的方法,估算了在采取不同的淘汰策略下土壤中DDT残留浓度的变化,以此来评价淘汰DDT的环境影响.与基线情景相比,三种控制情景下DDT的累积生产量都有不同程度的减少,相应土壤中的残留浓度也有不同的下降,且淘汰的速度越快土壤中DDT浓度下降的幅度越大.     

低温等离子体治理H2S污染的实验研究

低温等离子体技术是一种高效、快速的污染消除技术，国内外都在对其进行广泛而深入的研究。采用脉冲电晕放电等离子体对空气中的硫化氢进行降解研究，探索了、脉冲峰压、脉冲频率、气体流量以及气体初始浓度对净化效果的影响，气体浓度由气相色谱仪测定。结果表明，脉冲电晕放电可以有效消除硫化氢污染，净化率随脉冲峰压和脉冲频率的增加而提高，随气体初始浓度和流量的增加而下降，且在初始浓度360mg／m^2、流量1200mL／min、脉冲峰压30kV、脉冲频率80Hz的条件下，处理后的气体中已检测不到H2S，根据色谱检测限（0．29mg／m^3）计算出的净化率≥99．92％。采用离子色谱对产物进行了定性分析，发现H2S经放电处理后主要产物为SO2和SO3。     

Effect of formaldehyde on biofilm activity and morphology in an ultracompact biofilm reactor for carbonaceous wastewater treatment.

The effects of formaldehyde on biofilm morphology and biomass activity were investigated in an ultracompact biofilm reactor (UCBR) for carbonaceous wastewater treatment. The wastewater contained a fixed amount of glucose (with a chemical oxygen demand concentration of 600 mg/L) and an increasing concentration of formaldehyde (ranging from 21.4 to 271.1 mg/L). An influent formaldehyde concentration higher than 75 mg/L could facilitate filamentous growth (on biofilm) control and lead to a higher biofilm density, which is desirable as it enhanced the UCBR performance stability. However, at an influent formaldehyde concentration higher than 214.4 mg/L, biomass production was inhibited and deteriorations of biofilm morphology and biomass activity were observed. This study showed that it was desirable to maintain an influent formaldehyde concentration lower than 202.2 mg/L, as this concentration could achieve a good biofilm morphology while not inhibiting its microbial activity.     

聚苯乙烯基离子交换纤维去除铅离子的应用研究

聚苯乙烯其离子交换纤维是一种理想的离子交换材料。它的特殊的物理形态决定它对一些有害气体如铅烟、颗粒铅等具有很好的净化作用，铅烟净化效率可达８０％；对水溶液中毒性铅离子去除率可达８６％。该纤维可做为治理毒性铅离子的材料。     

Longitudinal emissions evaluation of mixed (cooperative) adaptive cruise control traffic flow and its relationship with stability

ABSTRACT

Cooperative adaptive cruise control (CACC) vehicles need vehicle-to-vehicle (V2 V) communication to achieve CACC function. When a CACC vehicle follows a manual-driven vehicle (MDV) without V2 V communication, it needs degenerate to adaptive cruise control (ACC). By using real experiments, California PATH program indicated that ACC vehicles are apt to be unstable, which may have negative influence on fuel consumption and traffic emissions. Hence, this paper studies the impacts of the mixed CACC-MDV traffic on fuel consumption and emissions, by taking into consideration partial degenerations from stable CACC vehicles to unstable ACC vehicles. To deal with this, microscopic simulations were adopted by using car-following models. Then, an appropriate emission model was used for evaluating the emission impacts under different CACC market penetration rates (MPRs). In order to obtain reliable evaluation results, the models validated by PATH program using real experimental data were employed as the CACC and ACC car-following models. In addition, we also analytically investigated stability of the mixed traffic flow under different CACC MPRs, in order to explore its relationship with the emission impacts. The results show that the fuel consumption and emissions firstly increase and then decrease with the increase of the CACC MPR. This means the mixed traffic under some ranges of CACC MPRs will produce more fuel consumption and emissions, compared with the full MDVs traffic. It indicates that stability situations of the mixed traffic qualitatively influence the impact trend of CACC MPRs on fuel consumption and emissions. Then, V2 V communication equipments on MDVs are not only encouraging but also essential to avoid the deterioration of fuel consumption and emissions of the mixed traffic flow.     

Effect of surfactants at low concentrations on the sorption of atrazine by natural sediment.

A series of experiments were carried out to determine the effect of surfactants at low concentrations on the sorption of atrazine by natural sediments. With surfactant concentrations ranging from 0 to 20 mg/ L, anionic and cationic surfactants appreciably reduce the adsorption of atrazine, while nonionic surfactant decreases the adsorption of atrazine at concentrations equal to or less than 1 mg/L and increases adsorption at higher concentrations. Desorption of atrazine in the presence of different sodium dodecylbenzene sulfonate (SDBS) concentrations shows that a portion of the bound pesticide resists desorption in the SDBS free system. However, the addition of SDBS accelerates the desorption of atrazine. Furthermore, the nature of sediment and the contacting sequence of SDBS, at 10 mg/L, with the sediment, also influence the adsorption of atrazine. The conclusions in this study could be explained partially by the effect of the type and concentration of surfactants and the characteristics of sediments.     

Levels of PCDDs and PCDFs in Korean river sediments and their detection by biomarkers

Polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) are a group of toxic halogenated aryl hydrocarbons inducing various physiological disorders against biological organisms. Here, we investigated their levels in sediment samples taken from 12 different rivers in Korea. The levels of PCDD/PCDFs in sediment samples were expressed as concentrations and international TEQ values. Among 17 PCDD/PCDFs selected as target compounds in this study, the 1,2,3,4,7,8-HxCDD and OCDD were found in all river sediments with significant variation in various congener profiles of PCDD/PCDFs in sediments. PCDD/PCDFs could be monitored by sensitive biomarkers using insect immune system. Out of 12 river sediment samples, the biomarkers reported four spots (up, middle, and down Singil sites and Ansan) as putative contamination areas. When comparing both chemical and biological monitoring results, two methods agreed three spots of Singil as contamination areas (above 10ppt levels) as well as six river sediment samples as relatively less-contaminated areas, but differed in the results in Ansan and Miho, probably due to relative non-specificity of biomarkers. Despite some disparity between bio- and chemical monitoring results, the biomarkers can be recommended as a device warning the contamination of dioxins in the environment because of a fast and inexpensive detection method.     

生物质固体废物厌氧发酵过程中HS对产CH4作用研究进展

针对生物质固体废物量大面广,具有污染和资源利用双重特性,厌氧发酵能源化可促进其污染控制,且过程中部分有机成分在微生物作用下转化成腐殖质（HS）.通过分析厌氧发酵过程中HS转化规律、HS结构特征与氧化还原性能、腐殖质还原菌与产甲烷菌活性、产CH₄效率之间的响应关系和作用机制研究进展,总结凝练出生物质厌氧发酵系统内HS对CH₄的调控原理,为减少厌氧发酵系统内HS对产CH₄途径的抑制作用,提高发酵效率的技术研究提供理论支撑.     

长江表层土壤多氯联苯污染特征及风险评价

采用气质联用仪（GC-MS）对长江流域13个干流断面及18个支流断面处沿岸表层土壤样品中的多氯联苯（PCBs）进行测定,分析其残留特征、污染来源和健康风险.结果表明,长江流域表层土中ΣPCBs的含量范围为：1.05~50.11ng/g dw,平均值为5.71ng/g dw,含量处于较低污染水平.干流的PCBs含量从上游到下游呈现逐渐增大的趋势,且PCBs在宜昌、岳阳、武汉、重庆等二三线城市总含量较高.PCB 17,PCB 18,PCB 44,PCB 74,PCB 87的检出率较高,三氯联苯、四氯联苯是主要的同系物,表明长江流域表层土壤主要以低氯联苯污染为主.主成分分析表明研究区域PCBs主要来自于1号国产变压器油、Aorclor 1242、1248、大气沉降及地表径流的混合污染源;对长江流域表层土壤健康风险评价表明,PCBs存在较小健康风险,呼吸摄入潜在风险低于经口摄入及皮肤接触.     

火山岩填料曝气生物滤池的SNAD工艺启动特性及功能菌丰度演替

为研究同步亚硝化、厌氧氨氧化耦合反硝化(SNAD)工艺在浸没式生物滤池反应器(SBAF)内的运行特性,同时接种亚硝化污泥和富集ANAMMOX的填料启动SNAD反应器.结果表明在60 mg·L~(-1)有机物浓度下,自养脱氮和反硝化实现较好的耦合,并在该浓度下稳定运行了67 d,其总氮去除率最高可达92.0%,COD去除率最高达82.9%,最高总氮去除负荷为2.3 kg·(m~3·d)~(-1).与全程自养脱氮(CANON)工艺相比,SNAD工艺的平均总氮去除率提高了12.6%.荧光定量PCR结果显示,系统启动后AOB菌的丰度有所增长,ANAMMOX菌的丰度增长了1个数量级,而NOB菌和反硝化菌的数量维持在较低水平(小于10~7 copies·g~(-1)),表明以火山岩为填料的浸没式生物滤池反应器有利于ANAMMOX和AOB的协同生长,可快速实现SAND工艺的启动.