土壤物理质量指标研究进展及在矿区环境中的应用展望

对土壤物理质量指标在国内外的研究进展进行了系统总结,在矿区环境中的应用进行了展望,构建了矿区环境土壤物理质量指标体系。常规指标的研究集中于耕作或人为干扰对指标影响的定量研究及物理、化学和生物学指标的相互影响。国外提出并应用了许多非常规指标来对土壤物理质量进行评价,结合常规指标,可以对自然或人为扰动情况下,土壤损伤及退化问题进行深入研究。采煤沉陷对土壤物理质量的影响是一个系统和复杂的过程,我国矿区土壤环境的研究,应该基于不同的研究目的,选择正确的常规和非常规指标来对矿区土壤物理质量进行系统的评价、表征及定量化。构建的矿区环境土壤物理质量指标体系,具有一定的参考和应用价值。     

COD测定仪法测定不同水样COD消解时间的差异性

通过实验证实COD测定仪法具有较好的精密度和准确性,与标准回流法的分析结果比较,相对误差为-3.37%~1.41%,具有替代标准回流法的可行性。由于水样性质不同,所需最佳消解时间不同,通过比较不同消解时间下COD测定的结果,得到COD测定仪法测定水中COD所需的最佳消解时间分别为:工业废水60 min,生活污水和地表水90 min。     

畜禽养殖废水生物处理剩余污泥臭氧减量过程中的重金属释放

采用臭氧氧化污泥减量法对畜禽养殖废水SBR中的剩余污泥进行处理。当臭氧反应时间控制在30min时，污泥的溶解比例在30％左右（以MLSS计）。上清液中一定量的SCOD溶出可为生物处理单元提供充足的碳源，同时在上清液中，TN、TP及水相重金属浓度增加有限，臭氧氧化后的污泥液回流污水处理系统后造成的N、P处理负荷较小，重金属对污泥微生物的活性抑制风险较低。若继续延长臭氧的反应时间，上清液SCOD、TN、TP以及重金属cu、Pb的释放速率明显增加，同时上清液的C／N降低，臭氧化后的污泥液回流反而不利于生物单元的脱氮处理。综合考虑TN、TP及水相重金属浓度增加的危害性，臭氧反应时间应控制在30min，臭氧实际投加量应为123．1mg O3／gSS。     

地面水力压裂对井下煤层瓦斯抽采影响分析

为了研究高河煤矿地面压裂钻井作业对井下煤层瓦斯抽采效果的影响，以3#煤层E2307工作面为主要考察对象，对水力压裂前后煤层渗透率、抽采瓦斯浓度和纯量进行统计分析。研究结果表明:地面压裂钻井水力压裂后煤层反演渗透率提高了13倍以上；压裂后瓦斯浓度最大增幅为122%，最小增幅为34%，平均增幅为71%，同样，瓦斯纯量也有大幅度的提高。研究认为高河煤矿地面水力压裂作业对其高瓦斯含量、低渗透性煤层具有良好的应用前景，对同类煤矿及煤层提高瓦斯抽采效率，预防井下瓦斯动力灾害具有积极的借鉴意义。     

臭氧-生物活性炭净水工艺处理苯酚污染的应急效果及影响因素分析

考虑到突发性水污染中有毒有机物的高频现率,选用苯酚为有毒有机物代表,通过模拟突发苯酚污染的情况,研究了臭氧-生物活性炭(O3-BAC)工艺对苯酚污染的应急处理效果,并且分析了工程中实际环境因素如空床接触时间(EBCT)、pH值对该应急能力的影响.研究表明,在突发性苯酚污染的应急处理中,0.6 mg/L的臭氧可将初始苯酚浓度5倍于达标浓度的进水处理至饮用水达标浓度,即低于0.002 mg/L,15.3 min的空床接触时间是判定其是否为该应急过程的关键因素的分界点,为了取得较好的应急效果,可适当提高进水pH值.     

Fracking and Framing: A Comparative Analysis of Media Coverage of Hydraulic Fracturing in Canadian and US Newspapers

Hydraulic fracturing, or fracking, is a controversial but popular method of extracting oil and gas in North America. There are a myriad of completing claims about the economic benefits and the environmental costs of the technology. This paper examines news media coverage of fracking in four Canadian and four American newspapers over a five-year period. A comparison is made at the national level as well as at a paired subnational level between jurisdictions where fracking is embraced and where fracking is banned. The paper demonstrates that in both countries the main storyline is about water quality, but beyond that differences emerge as Americans focus more on wildlife and public health and Canadians focus more on moratoriums and energy independence. Moreover, while there were similarities in media coverage of fracking in pro-fracking and anti-fracking jurisdictions, there were notable differences in attention to the topics of public health and economic benefits.     

Evaluating Flow Metric‐Based Stream Classification Systems to Support the Determination of Ecological Flows in North Carolina

Hydroecological classification systems are typically based on an assemblage of streamflow metrics and seek to divide streams into ecologically relevant classes. Assignment of streams to classes is suggested as an initial step in the process of establishing ecological flow standards. We used two distinct hydroecological river classification systems available within North Carolina to evaluate the ability of a hydrologic model to assign the same classes as those determined by observed streamflows and to assess the transferability of such systems to ungaged streams. Class assignments were examined by rate of overall matches, rate of class matches, spatial variability in matches, and time period used in class assignment. The findings of this study indicate assignments of stream class: (1) are inconsistent among different classification systems; (2) differ between observed and modeled data; and (3) are sensitive to the period of record within observed data. One clear source of inconsistency/sensitivity in class assignments lies with the use of threshold values for metrics that distinguish stream classes, such that even small changes in metric values can result in different class assignments. Because these two hydroecological classification systems are representative of other classification systems that rely on quantitative decision thresholds, it can be surmised that the use of such systems based on stream flow metrics is not a reliable approach for guiding ecological flow determinations.     

Butterfly community shifts over two centuries

Environmental changes strongly impact the distribution of species and subsequently the composition of species assemblages. Although most community ecology studies represent temporal snap shots, long‐term observations are rather rare. However, only such time series allow the identification of species composition shifts over several decades or even centuries. We analyzed changes in the species composition of a southeastern German butterfly and burnet moth community over nearly 2 centuries (1840–2013). We classified all species observed over this period according to their ecological tolerance, thereby assessing their degree of habitat specialisation. This classification was based on traits of the butterfly and burnet moth species and on their larval host plants. We collected data on temperature and precipitation for our study area over the same period. The number of species declined substantially from 1840 (117 species) to 2013 (71 species). The proportion of habitat specialists decreased, and most of these are currently endangered. In contrast, the proportion of habitat generalists increased. Species with restricted dispersal behavior and species in need of areas poor in soil nutrients had severe losses. Furthermore, our data indicated a decrease in species composition similarity between different decades over time. These data on species composition changes and the general trends of modifications may reflect effects from climate change and atmospheric nitrogen loads, as indicated by the ecological characteristics of host plant species and local changes in habitat configuration with increasing fragmentation. Our observation of major declines over time of currently threatened and protected species shows the importance of efficient conservation strategies.     

水力停留时间对MBR中溶解性微生物产物生成的影响

考察水力停留时间(HRT)对MBR中膜污染的主要污染物——溶解性微生物产物(SMP)生成的影响。结果表明,在装置稳定运行期间,MBR中SMP随运行时间出现累积。与HRT为8 h相比,HRT为12 h时,SMP在MBR中平均累积量要少10.1%,SMP中多糖含量平均高7 mg/L左右,而蛋白质含量平均低45.6%。SMP的平均粒径随装置运行呈下降趋势,并且HRT较短有利于粒径较小的SMP生成,从而堵塞膜孔;HRT较长有利于粒径较大的SMP生成,从而形成凝胶层,两种情况导致膜污染的机制不同。     

Modeling Changes to Streamflow,Sediment, and Nutrient Loading from Land Use Changes Due to Potential Natural Gas Development

Natural gas development using hydraulic fracturing has many potential environmental impacts, but among the most certain is the land disturbance required to build the well pads and other infrastructure required to drill and extract the gas. We used the Soil and Water Assessment Tool (SWAT) model to investigate how natural gas development could impact streamflow and sediment, total nitrogen (TN), and total phosphorous (TP) loadings in the upper Delaware River Basin (DRB), a relatively undeveloped watershed of 7,950 km² that lies above the Marcellus Shale formation. If gas development was permitted, our projections show the DRB could experience development of over 600 well pads to extract natural gas at build out, which, with supporting infrastructure (roads, gathering pipelines), could convert over 5,000 ha from existing land uses in the study area. In subbasins with development activity we found sediment, TN, and TP yields could increase by an average of 15, 0.08, and 0.03 kg/ha/yr, respectively (an increase of 2, 3, and 15%, respectively) for each one percent of subbasin land area converted into natural gas infrastructure. At the study area outlet on the Delaware River at Port Jervis, New York, we found increases in the annual average streamflow and sediment, nitrogen, and phosphorus loads of up to 0.01, 0.2, 0.2, and 1%, respectively, for a rapid development year, and 0.08, 1.3, 2.0, and 11%, respectively, for the full development scenario. Editor's note : This paper is part of the featured series on SWAT Applications for Emerging Hydrologic and Water Quality Challenges. See the February 2017 issue for the introduction and background to the series.