某炼铁厂炉顶除尘系统的风量调整与仿真分析研究

某炼铁厂炉顶除尘设备运行中各吸尘点风量失衡,造成除尘系统不能发挥应有的作用.通过对除尘系统各吸尘点风量及阻力、除尘器性能、风机性能等参数进行测试,并利用Fluent对系统内流场分布进行仿真与评估、对系统阻力平衡点进行分析,重新调整各个调节阀的开度,优化系统各吸尘点风量分布.调整后,不仅使系统达到现有条件下最佳除尘效果,而且找出了除尘系统设计及运行缺陷,提出了可行的解决方案.     

活性炭吸附二硫化碳解析气相色谱法测定废气中乙酸乙酯和乙酸丁酯研究

采用活性炭管吸附废气中的乙酸乙酯和乙酸丁酯,经二硫化碳萃取解析,使用DM-1色谱柱分离后FID检测.实验结果表明:(1)采用活性炭管吸附废气中的目标组份,富集效率良好,二硫化碳解析率可达92％以上;(2)当乙酸乙酯和乙酸丁酯的含量为6.8～102 ng时,测定结果的相对标准偏差分别在1.8％ ～4.2％和3.2％ ～6.1％之间(n=6);(3)当样品采集量为30 L时,方法检出限分别为0.02 mg·m-3和0.02 mg·m-3.因此,方法能满足实验对空气废气中的乙酸乙酯和乙酸丁酯的检测要求.     

烟台市环境空气自动监测中PM10与PM2.5数据异常情况分析研究

根据2014年烟台市范围内全部环境空气自动监测点位的PM 10和PM2.5数据,分析了不同监测仪器组合下PM10和PM2.5的倒挂情况,选取了倒挂率较高的4种监测仪器组合,将监测数据分为不同季节和时段比较分析,结果表明:大气湿度较高的季节倒挂率高于其他季节,夜间倒挂率高于昼间,雾霾等重污染天气时高于其他时段.数据采集频率、监测方法、监测仪器、采样管加热方式不同以及测量误差等都是产生倒挂现象的因素.     

基于无线通讯技术的起重机抬吊同步控制系统改进

本文介绍了基于无线工业以太网通讯的可编程同步检测系统结构和设计方法、同步功能的检测原理及实现方法、调试和操作方法。通过在控制系统中加入信号反馈,将两台起重机的控制执行器信号和末端机械传动的差异值进行反馈跟踪,组成具有反馈功能的抬吊控制系统,在监測到执行器异步或末端传动异步现象时及时控制两车同步停止,从而避免吊物坠落等吊运事故的发生。     

Species identification and mutation breeding of silicon-activating bacteria isolated from electrolytic manganese residue

Environmental Science and Pollution Research - A strain of silicon-activating bacteria was isolated from electrolytic manganese residue (EMR); identified as a species of Ochrobactrum by integrated...     

Simultaneous measurements of arsenic and sulfide using diffusive gradients in thin films technique (DGT)

Diffusive gradients in thin films technique (DGT) is a dynamically passive sampling technique which has been applied increasingly to the environmental monitoring field. In the preliminary period, the DGT with zirconium hydroxide-silver iodide as the binding phase (ZrO-AgI DGT) has been developed for the determination of sulfide (S(II)). On this basis, this paper developed its determination method for inorganic arsenite (As(III)) to further realize the simultaneous and high-resolution measurements of labile inorganic As and S(II) in sediments. ZrO-AgI binding gel had a strong ability in adsorbing and fixing As(III), showing a linear increase in the initial 12.5 min. After saturation of S(II) on ZrO-AgI binding gel, the adsorption rate and adsorption capacity of As(III) reduced by 8 and 14%, respectively. A stable elution rate (89.1 ± 2.2%) was obtained by extraction of As(III) on the binding gel using a mixture solution of 1.0 M NaOH and 1.0 M H₂O₂ (1:1). The DGT capacity of As(III) determined by the ZrO-AgI DGT was 23.6 μg cm^?2. DGT uptakes of As(III) were independent of pH (4.0–9.0) and ionic strength (0.01–100 mM), and they did not interfere with each other during the uptake process. Simultaneous measurements of labile As and S(II) in four sediment cores of Taihu Lake (China) with ZrO-AgI DGT showed that they had similarly vertical distributions in the top 16-mm layer in one core and in the whole profile up to the 35 mm depth in two cores. It likely reflected a simultaneous release of As and S(II) in sediments by synchronous reduction of As-hosted oxidized iron and sulfate, respectively. The simultaneous decreases of labile As and S(II) from their co-precipitation (e.g., As₂S₃) were not obvious in deeper sediment layer through the measurement with ZrO-AgI DGT.     

浸水条件下环氧微表处与沥青路面层间抗剪性能的试验研究∗

微表处在工程应用过程中受水与车辆荷载作用,容易产生推移或整片剥落。为此,在微表处中添加适量不同种类的水性环氧树脂(Water-borne Epoxy Resin,WER)形成环氧微表处,通过拉伸试验和自主设计的45°斜剪试验,研究WER对环氧微表处在浸水条件下层间抗剪性能的影响。试验结果表明:胶结料在掺入刚性较大的WER后,随浸水时间增加,胶结料塑性变形能力削弱,弹塑性阶段与塑性阶段减短,脆性增加,而掺加柔性的WER,塑性阶段持续时间较长;浸水状态下,环氧微表处与沥青路面的层间抗剪强度影响因素主次顺序为油石比WER掺量WER掺加方式,而切向变形率的影响因素主次顺序为WER掺量WER掺加方式油石比。在工程应用中,建议采用油石比7%、WER掺量8%～12%且将环氧树脂与固化剂预先调和后加入水中,然后与集料进行拌合。     

Treatment of mature landfill leachate by biofilters and Fenton oxidation

A series of processes by biofilter and Fenton oxidation to treat mature landfill leachate has been devised. At a hydraulic loading rate of 20 l m^?3 d^?1, a biofilter packed with aged refuse is found to remove 80% of chemical oxygen demand (COD), 89% of ammonia nitrogen and 96% of total phosphorus (TP). Particularly, TP levels dropped below 1 mg l^?1. The optimal condition for Fenton oxidation was selected to be an initial pH of 5, a dosage of 0.01 and 0.02 mol l^?1 of FeSO₄ and H₂O₂, respectively, and a duration of 3 h, where COD removal efficiency reaches 58.6%, and BOD₅/COD ratio is raised from 0.05 to 0.20. Subsequent treatment by a biofilter packed with slag reduces COD, ammonia nitrogen levels to less than 100, 25 mg l^?1, respectively. A pilot scale experiment conducted in situ demonstrates that this series of processes exhibits a high efficiency in removing pollutants from mature landfill leachate and it is viable for application.     

北京官厅水库周边土壤DDTs和HCHs暴露特征与风险评价

围绕北京水源地官厅水库周边2～10km范围于2009年系统布点,利用超声-振荡提取技术,使用气相色谱-电子捕获检测器(GC-ECD)分析方法测定了样品中的DDTs和HCHs含量.并利用GIS技术和地统计分析方法,研究其空间变异特征.结果表明,2009年官厅水库周边土壤中HCHs和DDTs的含量分别为n.d.～14.97ng·g-1(平均值0.73ng·g-1)、n.d.～64.91ng·g-1(平均值6.46ng·g-1).HCHs的残留以β-HCH为主,占总量的94.5%,DDTs的残留以p,p′-DDE为主,占总量的78.5%.不同土地利用类型中有机氯农药残留也不同,表现为果园农田荒地的趋势.Levene'sTest齐性检验结果显示,3种土地利用方式下HCHs和DDTs的残留差异并不显著.空间分析表明,其暴露格局受土地利用方式的影响,基本呈库北高于库南的趋势,高风险区集中在东部延庆县、中部的北辛堡镇以及西部的怀来县城附近.通过与我国土壤环境质量标准及荷兰土壤修复标准对比,并结合单因子污染指数法评价,本地区土壤中农药类POPs暴露仍处于较低的水平,环境风险较小.