Time series in M dimensions: The one-dimensional case: Pollution in the Chicago Sanitary and Ship Canal

A nonstationary time-series model is used to examine the changes occurring at sampling stations on the Chicago Sanitary and Ship Canal. Using data from upstream sampling sites, downstream levels of dissolved oxygen, total dissolved solids, nitrates and nitrites, and ammonia are accurately predicted. The method is simple, insensitive to extreme values, and responsive to changes in the system.     

Contamination of Oxygen-Consuming Organics in the Yellow River of China

Contamination of oxygen-consuming organics (OCOs) was one of the most serious problems in the Yellow River of China. This study was conducted to analyze monitoring of the data on OCOs contamination for the river in 1980 and during 1992–1999 as well as examining the effect of suspended solids (SS) on chemical oxygen demand (COD_Mn) and biochemical oxygen demand (BOD₅) of river water. Several significant results have arisen from the study. First, COD_Mn and BOD₅ of the river water showed an increasing trend from the upper to the lower reaches of the mainstream. BOD₅ values of river water in 1992 were significantly higher than those in 1980 and showed an increasing trend during 1992–1999. Second, OCOs in river water of the mainstream was attributed mainly to point sources; the ratio of point to non-point sources of BOD₅ was about 2.81. The load from point sources showed an increasing trend during 1992–1998. In contrast, the load from non-point sources manifested a decreasing trend during this period; this was caused by the decreasing trend of SS content in river water. The total load of BOD₅ from point and non-point sources displayed an increasing trend during 1992–1998. Third, as the humic substances in SS can hardly be biologically oxidized in natural conditions but can be oxidized by chemical oxidants such as potassium permanganate, COD_Mn was not suitable for being regarded as a parameter reflecting the pollution degree of OCOs in river water with a high SS content.     

风浪扰动对太湖水体中砷在水相-悬浮物相之间分配的影响

在太湖冬季不同风速下(0.8、1.8、2.7、3.2、4.0 m·s-1)采集了不同深度(水深0.1、1.0和1.8 m,分别记为上、中和下层)的水样,测定了水体和悬浮物中的砷含量及水质参数,计算了砷在两相之间的分配系数,以期了解在太湖生物活动最低的阶段,风浪扰动作用对砷在水相和悬浮物相之间分配的影响.结果显示,随着风浪作用的加强,水体总砷含量有所增加,相应的悬浮物总砷含量及砷的分配系数降低,说明风浪作用可以降低悬浮物吸附砷的能力,以至于促进砷从悬浮物中的释放,进而使水体中的溶解态砷增加.相关性分析及变化趋势比较分析发现,砷分配系数的降低与在风浪扰动的影响下悬浮物浓度和溶解氧的增加,以及叶绿素a浓度的下降有关.不同风速下各参数的垂向分布变化显示,风浪扰动对中下层的砷分配系数以及中层的悬浮物砷含量影响较大;风速变大时,中层溶解态砷含量升高,上层与下层溶解态砷含量降低;而风浪扰动作用对水体总砷的分层变化影响不大.悬浮物浓度、砷浓度及分配系数均在3~4 m·s-1风速下发生变化,且呈现与之前不同的分层特征.4 m·s-1可能是一个临界风速,在4 m·s-1以上的风速下风浪占主导作用,而4 m·s-1以下是湖流与风浪共同作用的结果.     

电吸附水处理技术(EST)对污水悬浮物去除效果研究

为了研究电吸附水处理技术(EST)对污水悬浮物的去除效果,本文采用电吸附水处理技术对生活污水中悬浮物进行处理分析,结果表明电吸附水处理系统对悬浮物的去除效果较好,去除率达到74.07%,而电吸附模块本身对悬浮物去除率仅为14.29%,氯离子、进水中悬浮物的浓度及进水中的硬度值均对悬浮物去除效率没有影响。因此,电吸附水处理技术可作为污水处理的一种新型有效方法。     

Surface clogging process modeling of suspended solids during urban stormwater aquifer recharge

Aquifer recharge,which uses urban stormwater,is an effective technique to control the negative effects of groundwater overexploitation,while clogging problems in infiltration systems remain the key restricting factor in broadening its practice.Quantitative understanding of the clogging process is still very poor.A laboratory study was conducted to understand surface physical clogging processes,with the primary aim of developing a model for predicting suspended solid clogging processes before aquifer recharge projects start.The experiments investigated the clogging characteristics of different suspended solid sizes in recharge water by using a series of one-dimensional fine quartz sand columns.The results showed that the smaller the suspended particles in recharge water,the farther the distance of movement and the larger the scope of clogging in porous media.Clogging extents in fine sand were 1 cm,for suspended particle size ranging from 0.075 to 0.0385 mm,and 2 cm,for particles less than 0.0385 mm.In addition,clogging development occurred more rapidly for smaller suspended solid particles.It took 48,42,and 36 hr respectively,for large-,medium-,and small-sized particles to reach pre-determined clogging standards.An empirical formula and iteration model for the surface clogging evolution process were derived.The verification results obtained from stormwater recharge into fine sand demonstrated that the model could reflect the real laws of the surface clogging process.     

可燃固体表面火蔓延行为研究进展与展望

固体可燃物表面火蔓延是森林火灾、建筑火灾以及工业火灾中普遍存在的燃烧现象,是火灾研究的基础问题。对固体可燃物表面火蔓延行为进行分类,评述国内外的固体可燃物表面火蔓延行为研究现状和目前存在的主要问题。总结固体可燃物表面火蔓延试验研究的技术手段,对比分析不同因素对建立固体可燃物表面火蔓延行为理论模型的影响。这些因素包括环境流场、化学反应动力学、热解气体组分和炭化过程等。概要介绍固体可燃物表面火蔓延计算模拟的优势。最后指出固体可燃物火蔓延行为研究的发展趋势,并提出未来若干重点研究方向。     

黄河不同粒径悬浮物中POC含量及输运特征研究

悬浮物(TSS)粒径与颗粒有机碳(POC)含量关系的研究,是河流POC形态变化及输送过程和输运通量研究的基础.本研究在沉降分级法基础上,结合激光粒度仪粒度测定和多元线性回归分析的数据处理方法,对2005-06-29黄河利津站、2005-09-27黄河口低盐度区以及2006年11月兰州、潼关、花园口各站TSS样品分析发现：黄河TSS中POC与其对应的中值粒径存在良好的负指数关系,POC的极限值为0.56%,普遍低于世界其它河流;黄河不同区段站位TSS性质不同使各样品相同粒级间POC存在明显的差异,黄河口站>花园口站>兰州站>潼关站>利津站,如<8 μm粒级TSS中POC依次是0.661%、 0.627%、 0.550%、 0.505%、 0.493%;黄河各粒级TSS所承载的POC量占样品POC总量的比例在不同区段各样品间极其相近,POC随TSS粒径增大显著递减, 80%以上的POC集中在<16 μm的TSS中,而粒径<32 μm的TSS承载了95%以上的POC.可见虽然黄河自西向东横跨5　000　km之多,落差达4　000　m以上,但POC的输运规律具有一致性,TSS粒径是控制POC输运特性的主要因素.     

3S技术在澳门邻近水域悬沙信息定量定位研究中的应用

遥感（ＲＳ）、地理信息系统（ＧＩＳ）和全球定位系统（ＧＰＳ）是空间信息定位和定量研究的强有力技术与方法．３Ｓ技术在其进行空间定位和定量研究中各有特点,本文综合各技术优势对澳门邻近水域悬浮泥沙信息进行了定位与定量研究．结果表明,澳门邻近水域的悬浮泥沙有明显的一个高浓度带和一个低浓度带,悬浮泥沙高浓度带分布在澳门地区的东南水域．悬浮泥沙的这一分布特点将对位于澳门半岛东南的澳门外港泥沙淤积有重要影响,这一结论对澳门外港的建设有一定指导意义．     

Hydrochemistry of drinking water sources and water purifiers in relation to epidemiological study in Hisar,North-West India

The concern related to the drinking of reverse osmosis (RO) water containing low levels of minerals is growing day by day. This study involves the analysis of water samples from various drinking water sources in a rural site, Mirchpur village, an Indus Valley civilization site (grid location: 29° 18′ 42.3″ N, 76° 10′ 33.0″ E) of Hisar, India, along with the health survey of human subjects. The hydrochemistry of water collected from hand pumps, river canals, tube wells, submersibles, and the RO systems installed in various homes was explored for pH, EC, TH, TDS, turbidity, cations (Na⁺, Ca²⁺, Mg²⁺), anions (CO₃²⁻, HCO₃⁻, Cl⁻, SO₄²⁻, NO₃⁻, F⁻), and elements (Fe, Pb, Se) employing the ion chromatography, flame photometry, and ICP-AES techniques. Lead (Pb) and Selenium (Se) were detected in trace amounts (0.30–2.6 μg L⁻¹; 0.10–4.1 μg L⁻¹, respectively) in all the samples, including the samples collected from RO purifiers, but Iron (Fe) was not detected in RO samples even in trace amounts. The F-levels in hand pump water (HPW) and submersible water (SW) (1.9  and 1.7 mg L⁻¹, respectively) and TDS levels in SW (3048 mg L⁻¹) were found to be above WHO and BIS safe limits. TDS levels in the river canal (900 mg L⁻¹), tube well (1104 mg L⁻¹), hand pump (1170 mg L⁻¹), and submersible samples (3048 mg L⁻¹) were found significantly higher as compared to the RO personal water (ROPW; 216 mg L⁻¹) and RO supply water (ROSW; 90 mg L⁻¹). The collected epidemiological data reveals that 21%, 19%, 13%, and 12% of natives reported skin, kidney, hair fall, liver, and stomach issues, respectively, suspecting the crucial role of high TDS and fluoride levels in the area. This study also provides a comparison between the quality of RO and the direct supply water, along with correlation matrices for different parameters, which gives a rationale for the limitations of drinking direct supply water without any purification and RO water containing low mineral content.     

生态清淤施工过程对巢湖水质影响的模拟

本研究以巢湖生态清淤为例,在水动力模型的基础上,采用平面二维恒定流和悬浮物扩散数学模型来描述生态清淤施工悬浮物的运动形态和排泥场尾水的影响。结果表明:生态清淤施工悬浮物扩散会给清淤区域内及周边约660 m范围的水体水质造成一定的影响。排泥场尾水排放口下游悬浮物最高浓度约4.8 mg/L,TN浓度最大增量约为0.164 mg/L,TP浓度最大增量约为0.004 mg/L。总体来说,尾水排放的SS、TN、TP对湖区的影响范围不大,其影响程度有限。