压裂返排液处理技术现状及展望

针对页岩气压裂返排液的特点、危害,综述了氧化-絮凝-过滤/吸附联合处理工艺、氧化-絮凝-电解-过滤/吸附联合处理工艺、氧化-絮凝-电解-过滤/吸附-生化联合处理工艺的特点、适用性及处理效果,经过多种工艺处理后,压裂返排液中COD等污染物可以有效去除,出水可以达标。并对压裂返排液处理技术的发展前景进行展望,认为回收重复利用是未来压裂返排液处理的发展趋势。     

Quantitative analysis of riparian herbaceous community in Liaohe River Conservation Area and its tributaries北大核心CSCD

Research on community characteristics of riparian herbs is an important scientific basis of riparian vegetation rehabilitation. This study aimed to investigate the species diversity and quantitative characteristics of riparian herbs in Liaohe River Conservation Area and its tributaries. Herbaceous communities were investigated by sample line method. Group average clustering analysis and detrended correspondence analysis (DCA) were used to find the major environmental factors affecting the distribution pattern of riparian herbaceous communities. The result showed altogether 154 herbaceous species, belonging to 40 families and 96 genera. The riparian herbaceous species diversity was found to be correlated to river slope, sinuosity and stream order, being lower in rivers of mountain area than in rivers of plain area, and higher in tributaries than in Liaohe River Conservation Area. Clustering analysis classified the herbaceous communities into 23 types, being dominated by hygrophytes including communities of Echinochloa crusgalli, Oenanthe javanica, Polygonum hydropiper, Murdannia keisak, Artemisia selengensis, Scirpus triqueter, Heleocharis soloniensis, Pycreus sanguinolentus, Cyperus fuscus, Phragmites australis, Polygonum amphibium, Carex diandra + Artemisia selengensis and Carex diandra + Rorippa islandica. Correlation analysis between DCA ordination axes and environmental factors showed that the altitude, river slope, sinuosity and stream level were the major environmental factors affecting the distribution pattern of herbaceous communities in the riparian zone of Liaohe River Conservation Area and its tributaries. The results of CCA showed that the contribution ratio of stream level was the highest, followed by altitude and slope, with sinuosity the last. The results suggested that riparian herbaceous characteristics are affected by the comprehensive force of altitude, river slope, sinuosity and stream order, and that Calamagrostis epigeios, Triarrhena sacchariflora and Phragmites australis are suitable species for riparian vegetation rehabilitation.     

沿海城市多灾种耦合危险性评估的初步研究——以福建泉州为例

如何处理区域内多灾种之间的相互作用关系是当前多灾种综合风险评估研究的热点和难点之一。在梳理沿海城市多灾种之间相互作用关系的基础上,提出一种基于触发关系的多灾种耦合危险性评估方法。首先选取多指标建立单灾种分级方案,计算单灾种初始危险性指数;然后构建基于触发关系的多灾种耦合规则,结合GIS技术进行空间耦合,计算耦合后的危险性指数;最后对耦合后的多灾种危险性的综合进行了探讨。以福建省泉州市为例进行了案例研究,结果表明:该方法在多灾种耦合危险性评估中具有可行性,为后续多脆弱性和多灾种综合风险的研究提供支持,为决策者进行科学风险管理提供依据。     

应用概率物种敏感度分布法研究太湖重金属水生生物水质基准

目前广泛使用的水质基准推导方法—物种敏感度分布法存在曲线拟合模型不确定、曲线拟合效果不佳、种内差异欠考虑、基准值不准确等诸多问题,概率物种敏感度分布法可有效解决上述问题。应用概率物种敏感度分布法构建了太湖水体中5种重金属Ag、Pb、Cd、Hg和Zn的概率物种敏感度分布曲线,在此基础上得到了保护水生生物的急性水质基准分别为1.079μg·L~(-1)、637.973μg·L~(-1)、19.465μg·L~(-1)、8.729μg·L~(-1)和105.506μg·L~(-1),慢性水质基准分别为0.108μg·L~(-1)、63.797μg·L~(-1)、1.947μg·L~(-1)、2.340μg·L~(-1)和52.753μg·L~(-1);不同类群间生物对重金属的敏感度存在差异,不同重金属对同一类群生物的毒性也存在差异;通过与国内外已有的重金属水质基准值比较,发现水质基准具有明显的区域性,目前基于国外水质基准或我国整体水域特点来制定的太湖水质标准,往往造成对太湖水生生物欠保护或过保护的状况。     

Molecular diversity of arbuscular mycorrhizal fungi at a large-scale antimony mining area in southern China

Arbuscular mycorrhizal fungi (AMF) have great potential for assisting heavy metal hyperaccumulators in the remediation of contaminated soils. However, little information is available about the community composition of AMF under natural conditions in soils contaminated by antimony (Sb). The objective of this study was to investigate the characteristics of AMF molecular diversity, and to explore the effects of Sb content and soil properties on the AMF community structure in an Sb mining area. Four Sb mine spoils and one adjacent reference area were selected from around the Xikuangshan mine in southern China. The association of AMF molecular diversity and community composition with the rhizosphere soils of the dominant plant species was studied by Polymerase Chain Reaction-Denaturing Gradient Gel Electrophoresis (PCR-DGGE). Results from all five studied sites showed that the diversity of AMF decreased with increasing Sb concentration. Principal component analysis (PCA) indicated that the AMF community structure was markedly different among these groups. Further redundancy analysis (RDA) showed that Sb contaminationwas the dominating factor influencing the AMF community structure in the Sb mine area. However, the multivariate analysis showed that, apart from the soil Sb content, extractable nitrogen content and organic matter content also attributed to AMF sequence distribution type. Some AMF sequences were only found in the highly contaminated area and these might be ideal candidates for improving phytoremediation efficiency in Sb mining regions. Gene sequencing analysis revealed that most species were affiliated with Glomus, suggesting that Glomus was the dominant AMF genus in the studied Sb mining area.     

Leaching-induced migration and compositional form change of Cu,Zn, and Cd from sludge to loess

Land utilization of sewage sludge has become one of the major issues in environmental mitigation in China. This is particularly important in the Loess Plateau of Northwest China. Sludge enriched with organic matter and nutrients might effectively help to resolve the problems of silty loess soils as evidenced by porosity defect, structural alterations and absence of fertility. After sludge flows into the loess, irrigation water contains heavy metals that leach and migrate into sludge and consequently related human health risks may occur that raise concerns; and this situation needs to be rectified. The characteristics of the vertical migration and composition form change of Cu, Zn, and Cd from composted sludge to loess, and corresponding influencing factors, were investigated by performing a soil column simulation test under the leaching treatment of a one-year irrigation water capacity. Results demonstrated that: (1) composted sludge significantly improved loess fertility, and irrigation leaching transported only a small quantity of organic matter in sludge in the plough layer; (2) although some of the Cu, Zn, and Cd in composted sludge migrated to and concentrated in the middle and upper layers of the soil column during leaching, these metals were mostly retained in the plough layer; and (3) after the leaching treatment of the one-year irrigation water capacity, the compositions of Cu, Zn, and Cd (particularly Cu and Zn) in both plough layer and loess began to stabilize with low concentrations in the exudate. These findings confirmed the applicability of composted sludge in loess regions. This study provided a new insight into the sludge reuse in alkaline soils in arid and semi-arid region.     

Response to environmental flows in the lower Tarim River, Xinjiang, China: ground water

In China's west since the 1950s large-scale ecosystem degeneration has occurred through water diversions for agricultural purposes. Since 2000, 1038 x 10(6) m(3) of water have been released into the Tarim River with the result that water reached the terminal Taitema Lake for the first time in 30 years. This environmental flow raised water-table levels along 350 km of the river. To assess the response of the water-table, a comparison "pristine" site is compared with downstream monitored sites. The results show huge changes in water-table levels. The study verifies that the water-table is extremely responsive to environmental flows, that strong internal similarities exist along the length of the river, and that the effect on the water-table and hence likely riparian vegetation recovery can be tentatively predicted. The actual impacts of the restoration strategy are less than those originally expected politically, socially and within the scientific community. We make recommendations on more effective release strategies.     

我国沿海地区水污染区域治理探讨

本文分析了我国当前水污染区域治理的难度，沿海地区水污染的主要问题，探讨了污染区域治理的基本原则，提出了水污染治理的重点区域和水污染区域治理的主要途径，并以浑河流域沈阳地区２０００年水污染物总量控制为例，概述总量控制方法和目标     

开发和建设西南能源基地是解决我国能源短缺的重要途径

西南地区是我国第二大能源基地，水能蕴藏可开发年发电量１．０３万亿ｋｗ·ｈ，占全国的５４％，煤炭保有储量７７０亿ｔ左右，占全国的１０％。和以山西为中心的能源基地一起，形成了“北煤南运”和“西电东送”两个格局。但是西南能源基地的水能资源开发程度很低，按发电量计算，仅占水电可开发总量的１．３％。目前能源短缺已成为我国工业发展中的突出问题。因此，合理布局、综合开发和建设西南能源基地，是解决我国能源短缺的重要途径。     

涟水县农业区域开发规划

搞好综合开发是建设现代化农业的战略措施之一,而要搞好综合开发,必先搞好农业区域开发规划。本文根据涟水地区的自然资源、社会经济条件和市场对农副产品及其制品需求出发,把涟水县域划分为2个开发区域,从分析开发的潜力入手,通过投资和效益的分析,提出了区域近、远期的开发目标、步骤和相应的开发措施。