纳米材料对低固相冲洗液性能影响的研究

低固相冲洗液是最适合绳索取心钻探工艺的冲洗液类型之一,但其防塌护壁能力和钻孔净化能力弱,阻碍了绳索取心钻探工艺在复杂地层的应用。本文通过实验研究,分析了纳米四氧化三铁、纳米氮化硼、纳米二氧化钛、多壁碳纳米管和纳米二氧化硅对低固相冲洗液的流变性能和滤失性能的影响规律。结果表明：纳米四氧化三铁、多壁碳纳米管和纳米氮化硼对低固相冲洗液的性能影响最明显,且具有增粘提切的作用。在此基础之上,通过正交实验分析了上述3种纳米材料复合后对低固相冲洗液性能的影响规律,得到性能优良的复合纳米低固相冲洗液体系优化配方：3%钠基膨润土+0.5%CMC-HV+0.3%纳米四氧化三铁+0.9%纳米氮化硼+0.9%多壁碳纳米管。最后,分析了纳米材料改善低固相冲洗液性能的作用机理。     

压滤技术在含氰尾矿处理工艺中的应用

应用压滤机处理含氰尾矿已有一些报道，作者在学习、借鉴基础上较系统地介绍了中试厂进行压滤试验，设备选型，流程设计及工业实践等情况，对中小型岩浆厂实施尾矿压滤工艺具有实用性和可操作性。     

The impact of well drawdowns on the mixing process of river water and groundwater and water quality in a riverside well field,Northeast China

Riverbank filtration (RBF) has been widely used throughout the world as an effective means to regulate surface water and groundwater resources and pretreat raw water for municipal water supply. The quality of the water from a riverside well field and the mixing ratios of surface water and groundwater is primarily impacted by the hydrodynamic processes in the RBF system. The RBF system is largely controlled by the water exploiting system in addition to the natural hydrologic condition of the river–aquifer system. As one of the most important design parameters of the riverside well field, the drawdown of groundwater level greatly determines the water head differences between the river water and groundwater as well as the field flow net, which subsequently impacts the mixing of river water and groundwater and water quality significantly. This study aimed to improve the understanding of the mixing process between the surface water and groundwater and estimate the impact of the RBF on the mixing ratio of surface water–groundwater and water quality quantitatively. A set of field pumping tests with various groundwater level drawdowns were carried out independently and successively at a riverside field with a single pumping well near the Songhua River in Northeast China in August 2017. During these tests, the water levels and hydrochemical parameters of the Songhua River, the adjacent aquifer, and the pumping well were monitored. The dynamic mixing process of the river water and groundwater and water quality under various drawdown conditions were analysed systematically using analytical methods. The results obtained from Dupuit method and the Mirror Image method in conjunction with the Hydrochemical Tracing method showed that the pumping water directly from the river water reached 60% ± 10% after a steady flow net was established. The larger the proportion of the pumping water captured from the river, the better quality of the pumping water was, because the quality of the river water (only limited to some water quality parameters monitored which were minority) was better than that of the groundwater. The results also showed that total Fe, TDS, total hardness, COD_Mn, and K⁺ were relatively sensitive to the changes of groundwater drawdown, and their concentrations decreased with an increase in the groundwater drawdown. It can be concluded that both the mixing ratio of the surface water and the groundwater and the water quality of the riverside well field can be regulated through adjusting the designed drawdown of the groundwater level, which is helpful for the design and the optimization of the riverside well water intake engineering.     

海水黄色物质吸收系数测量中的关键问题探讨

黄色物质是海洋中的有色可溶性有机物,是重要的水质参数之一。目前实验室黄色物质样品测量技术虽已有标准参考,但测量过程的一些重要变量对测量结果的定量影响仍未明确。基于2016年东印度洋南部水体综合调查所得的实测样品,分析了参比纯水是否过滤和过滤压力等因素对测量结果准确性的具体影响,发现:(1)参比纯水未过滤会使测量结果明显高估,ag(350)和ag(440)的高估程度分别为0.137 m~(-1)和0.114 m~(-1);(2)过滤压力的不同对测量结果影响较为明显,过滤压力越大,测得的吸收系数越大,对于a_g(350),150 mm Hg相对100 mm Hg的平均偏差为0.195 m~(-1),200 mm Hg相对150 mm Hg的平均偏差为0.058 m~(-1);对于ag(440),150 mm Hg相对100mm Hg的平均偏差为0.168 m~(-1),200 mm Hg相对150 mm Hg的平均偏差为0.064 m~(-1)。本文的实验研究可促进实验者对规范中黄色物质样品处理过程以及相关参数设置原因和意义的理解。     

极限保土状态下的反滤机制试验研究

提出了反滤系统极限保土状态的概念,分别采用4种不同孔径的钢丝编织网进行粉土反滤试验,研究反滤系统的极限保土状态。试验表明,当滤网孔径O和粉土特征粒径d85的比值等于12时,反滤系统才达到极限保土状态。极限保土状态下的反滤系统,在淹没式出流条件下,经往复水流作用26 h后改为单向水流,水力梯度从3.8逐渐增加到9.1,并在9.1的水力梯度下持续渗透453.25 h,反滤系统仍保持稳定,未发生失稳破坏;在非淹没式出流条件下,水力梯度从5.3逐渐增加到12.7期间,反滤系统保持稳定,但在维持12.7的水力梯度下持续渗透261.83 h后,反滤系统发生失稳破坏。对极限保土状态的研究有助于工程设计中更加合理地确定织物滤层孔径上限,减少淤堵。     

Seasonal and spatial distribution of redox zones during lake bank filtration in Berlin,Germany

Redox processes during bank filtration were evaluated in Berlin, where bank filtered water is abstracted for drinking water production. The investigations included the mapping of the infiltration zone, a column study and hydrochemical analyses of the groundwater sampled between lake and production well. The organic carbon content increased and the permeability of the lake sediments decreased with distance from the shoreline. The most important changes with regard to the redox state of the infiltrate occurred within the first metre of flow. Infiltration was mostly anoxic, as oxygen was rapidly consumed within the organic rich sediments. The infiltration zone revealed a vertical redox stratification with hydrochemical conditions becoming more reducing with depth rather than with distance from the lake. The redox zones were found to be very narrow below the lake and wider towards the production wells, suggesting that other than differing flow paths, reaeration after infiltration may also occur and possible mechanisms are presented. Redox conditions were influenced by strong annual temperature variations of the surface water affecting the microbial activity. Aerobic infiltration only took place close to the shore in winter.     

Soil-Column Test on Aniline Degradation in Riverbank Filtration under Denitrification Conditions

INTRODUCTION Riverbankfiltration(RBF)isaprocessbywhich surfacewaterissubjectedtogroundpassagebeforebe ingcollectedandusedasadrinkingwatersource(His cockandGrischek,2002;Rayetal.,2002;Doussanet al.,1997).Duringinfiltrationandtravelthroughthe riverbedandaquifersediments,surfacewaterissubjec tedtoacombinationofphysical,chemical,andbiologi calprocessesthatcansignificantlyimprovetherawwa terquality(HiscockandGrischek,2002).Thus,RBF hasbeenusedasapretreatedmethodtoimprovedrink ingwate…     

The effect of salinity on clearance rate in the suspension-feeding estuarine gastropod Crepipatella dilatata under natural and controlled conditions

The suspension-feeding gastropod Crepipatella dilatata occurs in estuaries in southern Chile that experience considerable fluctuations in salinity, driven by tidal and atmospheric forces. In the Quempillén estuary salinities as low as 9 psu may occur after severe rainstorms, and persist for several hours. In this study salinity was the major factor influencing the clearance rate of C. dilatata. At salinities below 20 psu, filtration ceased, whereas at high salinities (>22 psu) mean clearance rate was 0.24 l h⁻¹ standard animal⁻¹ (S.D. 0.18) for actively filtering individuals. This was confirmed by laboratory experiments under controlled conditions. Endoscopic observations were consistent with measurements of clearance rate, and showed that at salinity 25–30 psu the rate of transport along the gill filaments of particulate material embedded in mucus was 759 μm s⁻¹ (S.D. 480), but particle transport ceased at and below salinity 20 psu. Complete or partial isolation of the mantle cavity from the environment may be a mechanism to protect soft tissues and/or incubated egg capsules from osmotic stress.