生物堆修复多环芳烃类污染土壤研究进展及工业化应用初试

土壤的多环芳烃污染日益受到社会关注,经济有效的生物修复技术逐渐成为研究热点,生物堆即其中新兴的技术之一。本文先结合国内外运用生物堆技术修复多环芳烃污染土壤的案例,从生物堆技术简介、修复过程影响因子、修复过程机理简析等三个方面进行综合阐述。在此基础上于某工业污染场地现场建立处理能力为500m3的生物堆进行为期6个月的工业化应用初试。运行结束后,各采样点最终浓度均低于风险评估中所确定的修复目标值,土壤中2环至6环的PAHs降解率依次分别为78%,55%,45%,43%和22%。最后对该技术在"土十条"出台后的研究应用进行展望。     

河南省鹤壁市淇河流域（淇县段）农业非点源污染状况调查及评价研究

为了解淇县淇河流域农业非点源污染状况,采用资料搜集为主,现场监测补缺、核实为辅的方法,对淇县农业面源污染进行了调查。选取2013年淇县下辖的各乡镇各污染源排放的COD、氨氮、总氮、总磷为评价指标,用等标污染负荷法分区域、分来源进行了污染负荷评价。结果表明：淇县等标污染负荷总计42051.61×106 m3/a,其中,西岗镇最高,等标污染负荷为8189.42×106 m3/a,灵山办事处最低,等标污染负荷为987．98×106 m3/a;畜禽养殖业源等标污染负荷最高,为36384.95×106 m3/a,其次是种植业源,等标污染负荷为3023.92×106 m3/a。污染负荷比中总磷污染负荷比最高占61%,其次是总氮占27%。     

乳化油电破乳研究进展与物性参数优化

为获取不同物性参数对油水乳状液电破乳效率的联合作用规律,系统分析国内外电破乳油水分离的前沿成果,归纳含水率、温度、无机盐、酸碱等参数对电破乳的作用,并得到优化油水乳状液电破乳分离的物性参数:含水率过大易造成乳状液的电导率发生剧增,统筹考虑油水分离的电能耗,一般将含水率控制在25%为宜;避免升温分散液滴产生电分散,破乳剂达到浊点的影响,以及热负荷增加,油水乳状液的电破乳温度控制在70℃为佳;无机盐能显著降低油水乳状液的稳定性,但过高的含盐浓度,使得乳状液的电导率增加,能耗也有所上升;控制乳状液中固体微粒的粒径不小于几十微米,避免掺混与油湿润角小、具有亲油特性的固体微粒,易于电破乳的进程。     

Distribution of heavy metals in the water column, suspended particulate matters and the sediment under hydrodynamic conditions using an annular flume

Sediment resuspension plays an important role in the transport and fate of heavy metals in the aquatic environment. In the present study, the release and binding forms of Cr, Cu, Zn, Pb under hydrodynamic conditions were investigated using an annular flume. Two sediments located at YLZ and GBD from Liangshui River, Beijing were resuspended for 10 hr at 0.159 and 0.267 m/sec, respectively. The concentrations of suspended particulate matters of YLZ were higher than those of GBD during resuspension, indicating that the former sediment is more sensitive to the velocity. Cr in the dissolved phase stayed nearly constant at about 2.25 and 1.84 μg/L for YLZ and GBD, respectively, due to the high percentage of its stable binding fractions in both sediments, while Cu, Zn, and Pb showed a fast release in the initial period of time. However, their concentrations in SPM generally decreased with time and were higher at the lower velocity of 0.159 m/sec, which resulted from the entrainment and depressing effect of larger size particles with lower heavy metal content, commonly referred to as the "particle concentration effect". In addition, the binding form and heavy metal fractions were also found to vary during the resuspension event. A decrease in the sulphide/organic matters bounded form in GBD sediment was observed, whereas no visible changes were perceived in YLZ site samples. This phenomenon is due to the oxidation of heavy metal-sulphide binding forms, which originated from its high acid volatile sulphide content in GBD sediment.     

Uptake of isoprene, methacrylic acid and methyl methacrylate into aqueous solutions of sulfuric acid and hydrogen peroxide

Multiphase acid-catalyzed oxidation by hydrogen peroxide has been suggested to be a potential route to secondary organic aerosol formation from isoprene and its gas-phase oxidation products, but the lack of kinetics data significantly limited the evaluation of this process in the atmosphere. Here we report the first measurement of the uptake of isoprene, methacrylic acid and methyl methacrylate into aqueous solutions of sulfuric acid and hydrogen peroxide. Isoprene cannot readily partition into the solution because of its high volatility and low solubility, which hinders its further liquid-phase oxidation. Both methacrylic acid and methyl methacrylate can enter the solutions and be oxidized by hydrogen peroxide, and steady-state uptake was observed with the acidity of solution above 30 wt.% and 70 wt.%, respectively. The steady-state uptake coefficient of methacrylic acid is much larger than that of methyl methacrylate for a solution with same acidity. These observations can be explained by the different reactivity of these two compounds caused by the different electron-withdrawing conjugation between carboxyl and ester groups. The atmospheric lifetimes were estimated based on the calculated steady-state uptake coefficients. These results demonstrate that the multiphase acid-catalyzed oxidation of methacrylic acid plays a role in secondary organic aerosol formation, but for isoprene and methyl methacrylate, this process is not important in the troposphere.     

An enormous Jurassic turtle bone bed from the Turpan Basin of Xinjiang, China

A spectacular new terrestrial Konzentratlagerst?tte is introduced from the Turpan Basin of Xinjiang, China that probably belongs to the late Middle Jurassic Qigu Formation. It contains a mass accumulation of “xinjiangchelyid” turtles preliminarily identified as Annemys sp. In the zone with the highest turtle concentration, complete and articulated turtle skeletons are tightly packed at a density of up to 36 turtles per square meter. The fossiliferous layer is thickened here and shows an erosional base. This high concentration zone outcrops approximately 10?m in length and shows no decrease in turtle density after exposing 2?m of the layer into the hillside. Adjacent is a more expansive zone of at least 10?m by 30?m. In this region, the fossiliferous layer is evenly thick, and approximately five, fully disarticulated turtles are present per square meter. A conservatively estimated 1,800 turtles may, therefore, have been deposited at this site. It is likely that these aquatic turtles gathered in a retreating water hole in a riverine environment during a drought, much as some aquatic turtles will do today, but perished when the habitat dried up completely. A following catastrophic rainfall event caused a debris flow, possibly channelized in a dry river bed, which transported complete turtles, disarticulated turtles, and mudstone clasts and deposited them after a short distance. This taphonomic model is consistent with previous environmental reconstructions of the Turpan Basin during the late Middle Jurassic in predicting the episodic breakdown of regional monsoonal circulation resulting in a seasonally dry climate with severe episodic droughts.     

生物活性炭纤维处理小区生活污水的试验研究

为了实现小区生活污水再利用,进行以聚丙烯腈活性炭纤维(PAN-ACF)为载体的生物膜法处理小区生活污水的实验研究,以生活污水中COD、NH3-N、SS、浊度、pH等为检测指标来研究反应器的处理效果,实验结果表明该反应器对生活污水中COD、NH3-N、SS、浊度有非常高的去除效率,而且抗冲击负荷能力较强,以上指标出水均符合"城市污水再生利用城市杂用水水质标准"(GB/T18920-2002)中城市绿化规定的水质标准。此外,实验表明聚丙烯腈活性炭纤维(PAN-ACF)作为生物膜载体具有很好的生物亲和性。     

考虑车辆限速区间和风险公平性的危险品运输网络优化

针对有路段风险约束的危险品运输网络优化问题,讨论了不同路段上车辆限速区间的变化对危险品运输风险和成本的影响.基于最小最大准则构建了双层规划模型:上层规划表示政府部门通过对不同路段设置不同的限速区间来最小化最大运输网络总风险和路段最大风险的上界值,并通过增加路段最大风险的上界约束来实现风险分布的公平性;下层规划表示危险品运输商选择鲁棒成本最小的路径.为求解模型,设计了粒子群优化算法.根据算例分析发现,政府管理部门通过实施车辆限速区间策略,在考虑风险公平性的同时,可以有效地控制危险品运输网络的最大总风险.     

基于事故分析的公路限高门架警告标志优化设置*

为优化设置公路限高门架警告标志,利用Kruskal-Wallis检验与二元logistic回归分析,从工效学及人因工程学角度剖析事故原因,基于大型车辆驾驶员视认特征与道路交通环境特点,提出警告标志前置设置最低要求,构建考虑大型车辆驾驶员视认角度标志前置距离模型,并提出预防措施。结果表明:限高门架高度警示标志设置不规范,导致停车安全距离不足,标志视认能力下降;根据模型得出公路限高门架警告标志前置参考距离,验证模型有效性,并有针对性提出限高门架警示标志优化设置意见。研究结果可为公路限高门架警告标志设置提供参考和借鉴。     

Impact of maximum sustainable yield on independent populations

We investigate a community of independent logistically growing populations under a common harvesting effort which leads to the total maximum sustainable yield (TMSY). It is surprising that in the case of two populations with approximately equal carrying capacities, TMSY is reached while both populations persist, although their biotic potential may differ substantially. In general, however, TMSY with a common harvesting effort implies suboptimal fishing of some populations, overfishing of others and extinction of the rest of the populations. Since extinction of populations is a rule rather than an exception and since a community of independent populations is more robust than an ecosystem with multiple trophic levels, we call for urgent retraction of all legal documents advocating MSY in ecosystems.