Research on polyhydroxyalkanoates and glycogen transformations: Key aspects to biologic nitrogen and phosphorus removal in low dissolved oxygen systems

In this paper, a study was conducted on the effect of polyhydroxyalkanoates (PHA) and glycogen transformations on biologic nitrogen and phosphorus removal in low dissolved oxygen (DO) systems. Two laboratory-scale sequencing batch reactors (SBR1 and SBR2) were operating with anaerobic/aerobic (low DO, 0.15–0.45 mg·L^-1) configurations, which cultured a propionic to acetic acid ratio (molar carbon ratio) of 1.0 and 2.0, respectively. Fewer poly-3-hydroxybutyrate (PHB), total PHA, and glycogen transformations were observed with the increase of propionic/acetic acid, along with more poly-3-hydroxyvalerate (PHV) and poly-3-hydroxy-2-methyvalerate (PH2MV) shifts. The total nitrogen (TN) removal efficiency was 68% and 82% in SBR1 and SBR2, respectively. In the two SBRs, the soluble ortho-phosphate (SOP) removal efficiency was 94% and 99%, and the average sludge polyphosphate (poly-P) content (g·g-MLVSS^-1) was 8.3% and 10.2%, respectively. Thus, the propionic to acetic acid ratio of the influent greatly influenced the PHA form and quantity, glycogen transformation, and poly-P contained in activated sludge and further determined TN and SOP removal efficiency. Moreover, significant correlations between the SOP removal rate and the (PHV+ PH2MV)/PHA ratio were observed (R²>0.99). Accordingly, PHA and glycogen transformations should be taken into account as key components for optimizing anaerobic/aerobic (low DO) biologic nitrogen and phosphorus removal systems.     

浙江省火电厂脱硫旁路开启现状及取消对策

介绍了浙江省火电厂应对旁路铅封采取的措施,比对了铅封前后旁路开启的情况和造成的影响,对造成旁路开启的原因进行了分析,提出了实施取消旁路应关注的要点。     

Dissolution behavior of metals from particulate matter emissions

Exposure to air particulate matter (PM) is linked to numerous health effects. In order to improve the understanding of the role of its metallic components, their solubility was examined by using serial short-contact dissolutions totalling 1?h and additional sequential contact periods of 1, 4, and 8 days. The dissolution experiments were performed in solutions containing the main biological electrolytes. ICPMS determinations were used to quantify the dissolved metals. The total compositions were determined after closed vessel microwave digestion. Large variations in the rate and completeness of the dissolutions were observed. Fast and extensive dissolutions within the short-contact time (e.g., Zn, Cd) as well as slow dissolutions persisting during the last contact period (e.g., Ni, Cu, Sb, Pb) were found for smelting emissions. The multi-element determinations also made it possible to identify relationships between dissolution of different metals and define gradual composition changes of residual PM. When comparing with dissolutions performed in de-ionized water, similar major fractions were observed at short-contact time for minor components of smelting or combustion emissions (e.g., V, Ni, Cd), suggesting a preponderance of easily available forms at the surface of the relatively inert particle cores. The use of these time sequential methods may help in (1) modeling metal partitioning in biological media and (2) investigating the causes of adverse effects attributed to air PM.     

Polycyclic aromatic hydrocarbons in surface sediments held in experimental mesocosms

Sediment was collected from three locations along a pollution gradient in Narragansett Bay and transplanted to controlled mesocosms. Total hydrocarbons and eleven individual polycyclic aromatic hydrocarbons (PAHs) were measured in these sediments over a period of 394 days. Total hydrocarbon concentrations increased in the “relatively uncontaminated”; (Rhode Island Sound) sediment that was held in the mesocosms, but did not change in the two other sediments. The concentrations of four PAHs: naphthalene, 2‐methyl naphthalene, 1‐methyl naphthalene and biphenyl, decreased in the “contaminated”; (Providence River) sediment during the experiment and the calculated half‐lives for these compounds were 287, 353, 321 and 333 days, respectively.     

改进型ABR+复合生物反应器处理糕点残渣废水

介绍了改进型ABR+复合生物反应器在糕点残渣废水处理工程实例中的应用,运行结果表明:该工艺运行稳定、操作简便、运行成本低,处理糕点残渣废水可获得良好的效果,出水水质达GB 8978—1996《污水综合排放标准》中的一级排放标准。     

液氮冻融破碎生物污泥制备生物絮凝剂

利用城市剩余生物污泥,采用液氮冻融破碎、提取液提取的方法制备了生物污泥絮凝剂。对絮凝剂的制备条件及其絮凝性能进行了研究,结果表明:采用液氮冻融破碎,pH为1.0的稀盐酸溶液作为提取液提取所制备的絮凝剂,对高岭土悬浮液的絮凝效率可达98.5%。液氮冻融破碎的次数对絮凝剂制备没有明显影响。同时考察了絮凝剂投加量以及絮凝体系的pH对絮凝剂絮凝活性的影响。     

Use of biomarkers in zooplankton for assessment of the ‘health status’ of marine and brackish environments: a short overview

The biomarker approach has been used for 25 years to study the environmental quality of marine, brackish and freshwater ecosystems. Biomarkers may indicate health status and can be applied to organisms of all zoological phyla by destructive or non destructive methods. For 5 years we have been using this approach in zooplankton to detect ecotoxicological alterations at low levels of the food chain due to contaminants. Here we review our approach to validate and apply biomarker techniques in zooplankton. We discuss advantages, limitations, some results and future research. We indicate that biomarkers in zooplankton can be used as new indices of trophic status and ecological integrity of Italian marine coastal and lagoon environments, to be included among the tools specified by Italian law D.Lgs. 152/2006.     

不同生境薇甘菊土壤种子库与幼苗库的特征

通过野外定点取样与萌发试验相结合的方法,研究云南德宏州陇川县不同生境薇甘菊入侵地区的土壤种子库与幼苗库的特征.结果表明,根据土壤种子库萌发后的植物鉴定结果,橡胶林、林地、灌丛、草地和河岸边这5种生境共统计到40种植物,隶属18科.不同生境薇甘菊入侵群落的物种组成、种子萌发特性与空间分布及其幼苗库存在明显差异,橡胶林、林地、灌丛、草地和河岸边的薇甘菊种子密度分别为75、109、165、124和53粒·m-2,且各生境间差异显著(P＜0.05).室内萌发试验表明,薇甘菊土壤种子库萌发时间持续8周,其中第3～5周的萌发速度最快;土壤垂直方向上,0～2、＞2～5、＞5～10 cm深度土层薇甘菊种子分别占0～10 cm土层种子总数的81％、17％和2％.野外薇甘菊土壤幼苗库萌发时间持续6个月(5-10月),其中6-8月萌发速度较快.     

水体沉积物质量基准研究现状

沉积物质量基准是对水质基准的补充,对水质管理具有重要意义。目前国际上沉积物质量基准计算方法有十几种。对各种方法的理论基础、数据需求、适用范围等方面进行了概述之后,综合分析了各种方法的理论基础。研究结果认为,应将建立沉积物质量基准的方法分为以生物效应数据为基础的生物效应数据库法和以相平衡分配原理为依据的相平衡分配法。而根据统计方法不同,生物效应数据库法又分为单值基准、双值基准和三轴图法。同时还对美国、加拿大、荷兰、英国、澳大利亚和新西兰的沉积物质量基准研究发展和应用概况进行了分析。结合我国实际情况认为,依赖于大量生物效应数据的生物效应数据库法,目前在我国的适用范围有限,只能用于推导少数几种污染物的基准值。相平衡分配法具有可靠的理论基础而且不需要大量的生物效应数据,具有很大的发展潜力。因此,对于目前沉积物质量基准研究处于初级阶段的我国,更适合使用相平衡分配法计算污染物沉积物质量基准。     

中部6省生态足迹的测算与比较分析

生态足迹方法是区域可持续发展研究的一种重要方法,在中部6省大区域框架下,运用生态足迹模型对中部6省1989—2011年的生态足迹进行了测算和对比研究。研究结果表明:中部6省1989—2011年的生态承载力较为平稳,其中江西、河南、湖北和湖南4省的生态承载力略有上升,而山西、安徽两省的生态承载力有下降趋势。中部6省的社会经济活动对生态系统的消耗远大于生态系统本身的承载能力,并且这种差距正在不断增大,导致生态赤字不断增大。考察期间,山西省生态赤字的绝对值最小,平均生态赤字为0.49 hm2 cap-1,湖北省生态赤字最大,平均值为1.15 hm2 cap-1,其次为河南和湖南,生态赤字增长最快的是山西省和河南省,增长倍数分别达到了7.38和4.27倍。中部6省6种生态生产性土地的生态足迹均呈现出上升趋势,平均来看,6类生态生产性土地在中部6省总的生态足迹中所占比重由高到低依次为耕地、化石能源地、草地、建筑用地、水域、林地。耕地生态足迹是生态足迹中最重要的组成部分,在总的生态足迹中所占比重最大,中部6省耕地的生态足迹时间序列数据比较平稳,在考察时间内从1989年的0.4241上涨到2011年的0.5851,上升趋势较平稳,但由于耕地生态足迹所占比重大,尽管增长速度缓慢,但对中部6省生态足迹总的影响较大。建筑用地和林地生态足迹虽然增长幅度较大,但由于基数小,因此建筑生态足迹和林地生态足迹对中部6省生态足迹总的影响较小。草地、水域和化石能源用地生态足迹基数大,增长幅度也大,加上耕地生态足迹,共同决定了中部6省人均生态足迹的逐年上升趋势。