THE EFFECT OF RESIDENTIAL DEVELOPMENT ON GROUND‐WATER QUALITY NEAR DETROIT,MICHIGAN1

ABSTRACT: Two water‐quality studies were done on the outskirts of the Detroit metropolitan area to determine how recent residential development has affected ground‐water quality. Pairs of monitor and domestic wells were sampled in areas where residential land use overlies glacial outwash deposits. Young, shallow waters had significantly higher median concentrations of nitrate, chloride, and dissolved solids than older, deeper waters. Analysis of chloride/bromide ratios indicates that elevated salinities are due to human activities rather than natural factors, such as upward migration of brine. Trace concentrations of volatile organic compounds were detected in samples from 97 percent of the monitor wells. Pesticides were detected infrequently even though they are routinely applied to lawns and roadways in the study area. The greatest influence on ground‐water quality appears to be from septic‐system effluent (domestic sewage, household solvents, water‐softener backwash) and infiltration of storm‐water runoff from paved surfaces (road salt, fuel residue). No health‐related drinking‐water standards were exceeded in samples from domestic wells. However, the effects of human activities are apparent in 76 percent of young waters, and at depths far below 25 feet, which is the current minimum well‐depth requirement.     

几种工业废水可生化性判定指标的验证与评价

测定了几种工业废水的可生化性指标BOD5/COD比值和相对耗氧速率,根据模拟生物氧化塘的动态运行试验结果,提出以耗氧速率(R％)作为可生化性的判定指标,它比BOD5/COD比值测定快速,方法简便,更接近实际,并得出两个指标与生物塘COD去除率之间相关性的线性回归方程,为选择废水生物塘处理方案、预估其对COD的去除效率提供了理论依据。      

BOD快速测定传感器的微生物膜固定方法研究

分别采用海藻酸钠包埋法、醋酸纤维素夹层法、戊二醛－牛血清白蛋白交联法等几种物理、化学方法制备固定化微生物膜,并采用自制的微生物ＢＯＤ传感器试验了各种膜对电极响应灵敏度,线性范围,响应时间,稳定性和寿命等性能的影响,比较了不同ｐＨ,温度和交联剂,包埋剂用量下该传感器的性能,获得了较满意的结果,实验表明,以交联法制备的传感器性能最佳,电极寿命达４０ｄ,测定ＢＯＤ值时间为１０－１５ｍｉｎ,方法的重视性和     

百脉泉泉群泉水氢氧稳定同位素时空变化特征

研究泉水氢氧稳定同位素时空变化特征,探究泉水的补给来源,对水资源管理及旅游业可持续发展具有重要指导意义。以百脉泉泉群为研究区,通过分析降水及泉水中的氢氧稳定同位素特征,获取了本地大气降水线、泉水同位素时空变化特征及蒸发线,并探究了百脉泉泉水的补给来源。结果表明：大气降水中δ²H的波动范围为-151.55‰δ¹⁸O—-4.28‰,δ¹⁸O的波动范围为-19.93‰δ¹⁸O—-0.52‰,δ²H和δ¹⁸O在时间上的分布规律相似,均呈现双峰状(“M”型),本地大气降水线(LMWL)为：δ²H=7.58×δ¹⁸O+4.17。百脉泉泉水的δ²H的波动范围为-65.23‰δ¹⁸O—-37.01‰,δ¹⁸O的波动范围为-8.99‰δ¹⁸O—-4.04‰。泉水δ²H—δ¹⁸O均落在本地大气降水线上或...     

模型公式法在确定BOD_5样品稀释系数中的应用

本文提出了一种利用以往监测数据计算ＢＯＤ５稀释系数的简易公式,为ＢＯＤ５测定中稀释系数的确定提供了一种科学准确的计算方法。本法不受经验因素的限制,并能确保ＢＯＤ５样品分析的可靠性与成功率,具有应用与推广价值。     

用开管法快速测定废水的COD

介绍了用硫酸锰代替硫酸银作催化剂快速开管测定废水COD的方法．最佳测定条件为：消解温度170℃,消解时间12min,酸度11mol／L,催化剂(硫酸锰)用量10g／L。该方法使试样的消解时间由标准法的2h缩短到12min,同时用硫酸锰代替价格昂贵的硫酸银可大大降低分析成本,而准确度和精密度与用硫酸银作催化剂的开管法基本相同,COD测定下限为65mg／L。该方法可同时消解多个试样．适用于大批量水样的测定。     

NiFe2O4直接分解二氧化碳成碳循环反应过程结构演变研究

用XRD Rietveld分析法,对共沉淀法制备的NiFe2O4在H2／CO2循环反应中的结构演变进行研究,发现随着循环反应次数的增加,NiFe2O4物相的含量逐渐降低,Fe2Ni1-x物相的含量及其(200)衍射的平均晶粒逐渐增大,并出现Fe3C物相,其含量增长较快．纯NiEe2O4经15次循环反应后,体系中NiFe2O4物相的含量只剩下5％左右,样品基本失去分解CO2的活性．NiFe2O4掺杂4％铬后,明显提高了NiFe2O4骨架结构的稳定性,虽经50次H2／CO2循环反应,体系中NiFe2O4物相含量仍然有20％,分解CO2的活性仍达到初始活性的40％．     

高海拔矿山掘进工作面局部供氧装置研究*

为缓解高海拔矿山掘进作业面低氧问题,将供氧管与环形空气幕相结合,空气幕在作业人员四周形成空气屏障,设计1种用于高海拔矿山掘进工作面的新型供氧装置。以中国云南某海拔3 400 m的铜矿为例,运用ANSYS Fluent软件建立掘进工作面空间模型,根据矿山实际情况确定边界条件,对比研究单一供氧管模式和新型供氧装置的富氧效果差异,并分析空气幕出风口形式、风量对富氧效果的影响。研究结果表明:新型供氧装置的富氧效果优于单一供氧管模式;环状缝隙出风口优于圆孔出风口,并且当环状缝隙宽度为0.010 m、风量为0.014 m3/s时,呼吸带平均氧气质量分数为27.59%,达到最佳富氧效果。新型供氧装置能有效提高作业人员周围呼吸带区域的氧气质量分数。     

新疆喀什三角洲地下水SO2-4化学特征及来源

"水质型"缺水问题是新疆喀什地区水资源紧缺的主要原因之一.位于喀什地区西部的喀什三角洲面积13 329 km~2,73. 2%面积的潜水和53. 2%面积的承压水SO_4~(2-)浓度超过地下水质量Ⅲ类标准,同时伴随有高TDS、高硬度等特征.运用δD、δ~(18)O-H_2O和δ~(34)S-SO_4~(2-)同位素等手段分析地下水SO_4~(2-)化学特征及来源.结果表明:①区内剥蚀山区钙质粉砂岩、钙质细砂岩和石膏等盐类矿物的溶解控制了流域水化学组成,形成了水化学类型以SO_4型为主的地表水和地下水.地下水化学类型演变方向为HCO_3·SO_4→SO_4→SO_4·Cl,山麓斜坡冲洪积砾质平原为溶滤-径流带,河流冲积平原为径流-累积带,上游至下游地下水化学成分趋向盐化;②区内地下水初始补给源主要为大气降水,且受一定蒸发作用影响.不同水文地质单元地下水δD和δ~(18)O分布特征明显,上游至下游,同位素值由低到富集,受蒸发作用由弱到强;冲积平原承压水同位素分布较离散,受到上覆潜水混合作用影响;③南部、北部山麓斜坡冲洪积砾质平原潜水SO_4~(2-)来源分别为海陆交互相和陆相蒸发岩的溶滤;河流冲积平原潜水SO_4~(2-)除了陆相蒸发岩溶滤来源外,还存在化肥淋滤的污染;承压水受蒸发岩溶滤外,还受到潜水的混合作用和细菌还原硫酸盐作用影响.     

Configuration influence in relation to fluid flow of venturi system

Due to its simplicity and accurately measuring the flow rate, the venturi system is a special kind of pipe that is widely used in various applied fluid mixtures. One of the venturi system's important applications is ejectors devices that accurately facilitate adding air to water to sustain oxygen demand target levels in many waterworks engineering systems. This study aims to improve venturi system measurement accuracy through experimental investigation and analytical analysis for the venturi system conditional configuration parameters effect on target aeration operational efficiency. In the experiment work, different runs are implemented to characterize the performance of such aerators by describing the impact of venturi characteristics and configurations, including water flow rate, air inlets orifices diameters, inlet velocities, throat lengths, inlet angles, outlets angles, and outlet diameters on aeration efficiency. Results show that the venturi air vent diameter is an important governing parameter for determining aeration performance value. Additionally, an indicated increase in aeration performance with an increasing throat length to its diameter ratio. Meanwhile, the results revealed a varying noted effect of the venturi system characteristics and configurations on aeration performance. Moreover, the equations that relate venturi system configuration and Reynolds numbers with the aeration operational performance are developed to facilitate the target accurate aeration efficiency estimation.