沙渗滤去除三家店水库水中有机污染物的试验研究

采用CODMn和BOD作为指标对沙渗滤系统去除三家店水库水中有机污染物的效果进行了评价.试验构建一个长约10m、宽2m、高2m的砖混结构渗滤池,渗滤池分隔为8个小渗滤池,选择3种不同的沙分别构建1m3见方的渗滤床.渗滤系统持续运行125d,经历高温的夏季和低温的冬季,试验结果表明,渗滤系统对三家店水库水中有机污染物能有效去除,CODMn去除率一般在20%～40%,BOD的去除率一般在20%～80%,CODMn、BOD的出水值分别小于4mg·L-1、3mg·L-1;渗滤层厚度的增加不能显著增加有机污染物的去除率;温度对CODMn和BOD的去除有明显的影响;3种渗滤介质对CODMn和BOD均能有效去除,建筑沙对去除有机质的效果相对好一点.     

改进地渗系统处理分散生活污水启动周期的研究

对传统型的地下渗滤系统进行了改进,建立了一套新型的地下渗滤试验装置.采用两种不同的进出水方式对此渗滤系统的启动周期进行了比较试验,结果表明:在进水CODCr为250～400 mg/L、氨氮为70～lOO mg/L时,初期采用间歇进水的方式可使启动周期缩短为18 d;稳定运行时HRT为6 h,COD去除率可达79%以上.此研究为新型地渗系统的设计提供了思路.     

Effects of Urban Development on Ant Communities: Implications for Ecosystem Services and Management

Abstract:  Research that connects the effects of urbanization on biodiversity and ecosystem services is lacking. Ants perform multifarious ecological functions that stabilize ecosystems and contribute to a number of ecosystem services. We studied responses of ant communities to urbanization in the Lake Tahoe basin by sampling sites along a gradient of urban land development. We sampled ant communities, measured vegetation characteristics, quantified human activities, and evaluated ant-community responses by grouping ants into service-providing units (SPUs), defined as a group of organisms and their populations that perform specific ecosystem services, to provide an understanding of urbanization impacts on biodiversity and their delivery of ecosystem services. Species richness and abundance peaked at intermediate levels of urban development, as did the richness of 3 types of ant SPUs (aerators, decomposers, and compilers). With increasing land development aerator and decomposer ants significantly declined in abundance, whereas compiler ants significantly increased in abundance. Competing models demonstrated that precipitation was frequently among the strongest influences on ant community structure; however, urban development and human activities also had a strong, negative influence on ants, appearing in most models with ΔAIC_c < 2 for species richness and abundance patterns of SPUs and generalists. Response diversity was observed within SPUs, which suggests that the corresponding ecosystem services were maintained until development reached 30–40%. Our data provide evidence that ecosystem functions, such as water infiltration and soil productivity, may be diminished at sites subject to greater levels of urbanization and that conserving ant communities and the ecosystem services they provide could be an important target in land-use planning and conservation efforts.     

降水入渗补给地下水过程分析

该文总结了降水入渗补给的模式,通过分析活塞式降水入渗、降水入渗补给的滞后和延迟、降水入渗优先补给等,研究了土壤不同岩性、不同埋深、不同降水时段与不同土壤含水量条件下的降水入渗补给过程．图5,表1,参8．     

渗灌——设施园艺先进的节水灌溉技术

渗灌具有降低室内湿度、改善土壤环境、节约灌溉用水、减少肥料用量、省工省时、价格适中等优点,是目前设施园艺先进的节水灌溉技术。详细介绍了渗灌系统的结构,渗灌管的种类以及使用维护方法。     

南亚热带丘陵土壤水分循环及其有效性的研究──Ⅲ.降雨入渗与地表径流

南亚热带高温多雨,年降雨量大而分布不均,台风雨季节降雨强度大,全年降雨多集中在4～9月,占全年的80％以上,因而大大地增加了降雨所引起的地表径流,径流也主要集中在多雨季节,特别是在5～8月,占全年降雨径流量的90％左右,形成了南亚热带坡地独特的地表径流特征．南亚热带的降雨入渗对表土层的影响较大,在暴雨过程中,0～30cm土层水分易产生饱和,因而易产生地表径流,从而减少水分入渗．这对作物生长产生不利的影响．     

Performance Assessment of Rain Gardens1

Abstract: The most widely used approach for evaluating the performance of stormwater best management practices (BMPs) such as rain gardens is monitoring, but this approach can involve a long time period to observe a sufficient number and variety of storm events, a high level of effort, and unavoidable uncertainty. In this paper, we describe the development and evaluation of three approaches for performance assessment of rain gardens: visual inspection, infiltration rate testing, and synthetic drawdown testing. Twelve rain gardens in Minnesota underwent visual inspection, with four determined to be nonfunctional based on one or more of the following criteria: (1) presence of ponded water, (2) presence of hydric soils, (3) presence of emergent (wetland) vegetation, and (4) failing vegetation. It is believed that these rain gardens failed due to a lack of maintenance. For the remaining eight rain gardens, an infiltrometer was used to determine the saturated hydraulic conductivity (K_sat) of the soil surface at several locations throughout each basin in what is termed infiltration rate testing. The median K_sat values for the rain gardens ranged from 3 to 72 cm/h. Synthetic drawdown testing was performed on three rain gardens by filling the basins with water to capacity where possible and recording water level over time. The observed drain times for two of those rain gardens were in good agreement with predictions based on the median of the infiltrometer measurements. The observed drain time for the third rain garden was much greater than predicted due to the presence of a restrictive soil layer beneath the topsoil. The assessment approaches developed in this research should prove useful for determining whether the construction of the rain garden was performed properly, a rain garden is functioning properly, and for developing maintenance tasks and schedules.     

生物填料地下渗滤系统处理生活污水的中试研究

以活性污泥等生物基质为填料.在不同的水力负荷和有机负荷条件下,研究了地下渗滤系统对生活污水的处理效果.中试结果表明:地下渗滤系统对COD、NH_4~+-N和TP有着良好的去除效果,在水力负荷为4 cm·d~(-1),污染负荷为280 mg·L~(-1)和320 mg·L~(-1)时.COD、NH_4~+-N和TP的去除去分别达到91.2%、97.2%、88.0%和90.6%、95.6%、90.4%;水力负荷达到450 mg·L~(-1)时,有机物及氨氮的去除率下降迅速,仅为83.2%和85.5%,TP的去除率略有提高,为91.7%;平均污染负荷为300 mg·L~(-1),水力负荷为4.0 cm·d~(-1)、6.5 cm·d~(-1)和8.1 cm·d~(-1)时,COD、NH+4_4~+-N和TP的去除率分别达到90.6%、97.4%、90.0%.87.3%、96.8%、84.0%和85.6%,96.3%,83.3%;适宜的生活污水处理条件是水力负荷为8.1 cm·d~(-1),污染负荷低于450 mg·L~(-1).在以上工况下的出水水质均优于生活杂用水水质标准(CJ251-89)和沈阳市污水处理中水回用标准,处理效果稳定;系统垂直方向的氨化细菌分布较均匀,硝化细菌在70 cm以上区域数量较多,反硝化细菌在70 cm以下区域数量较多;氨化细菌与COD、NH_4~+-N和TN的去除率的相关性显著,硝化及反硝化细菌与COD、NH_4~+-N和TN的去除率的相关性极显著;氨化、硝化和反硝化细菌与TP的去除率的相关性均不显著,说明生物作用不是TP脱除的主要途径.     

三级人工快渗系统脱氮效果及菌种分布分析

为了更有效地去除污水中的氮类污染物,采用三级串联人工快渗系统对高氨氮生活污水进行脱氮性研究,同时进行系统内菌种分布的特征分析,从微观角度对比传统人工快渗和新式三级串联人工快渗系统中微生物分布的区别。结果表明三级串联人工快渗系统对氨氮和总氮(TN)的去除率较常规人工快渗系统分别提高5%和21%。三级串联人工快渗系统内硝化细菌和反硝化细菌总数均大于传统人工快渗系统。反硝化细菌数量的显著提高是总氮(TN)去除提高的主要原因。同时发现三级串联人工快渗系统可以有效地缓解堵塞现象的发生。     

Projections of 21st Century Sierra Nevada Local Hydrologic Flow Components Using an Ensemble of General Circulation Models1

Abstract: Sierra Nevada snowmelt and runoff is a key source of water for many of California’s 38 million residents and nearly the entire population of western Nevada. The purpose of this study was to assess the impacts of expected 21st Century climatic changes in the Sierra Nevada at the subwatershed scale, for all hydrologic flow components, and for a suite of 16 General Circulation Models (GCMs) with two emission scenarios. The Soil and Water Assessment Tool (SWAT) was calibrated and validated at 35 unimpaired streamflow sites. Results show that temperatures are projected to increase throughout the Sierra Nevada, whereas precipitation projections vary between GCMs. These climatic changes drive a decrease in average annual streamflow and an advance of snowmelt and runoff by several weeks. The largest streamflow reductions were found in the mid‐range elevations due to less snow accumulation, whereas the higher elevation watersheds were more resilient due to colder temperatures. Simulation results showed that decreases in snowmelt affects not only streamflow, but evapotranspiration, surface, and subsurface flows, such that less water is available in spring and summer, thus potentially affecting aquatic and terrestrial ecosystems. Declining spring and summer flows did not equally affect all subwatersheds in the region, and the subwatershed perspective allowed for identification for the most sensitive basins throughout the Sierra Nevada.