火焰原子吸收法测定水中铜的不确定度评定

详细叙述了火焰原子吸收法测定水中铜含量的操作步骤及标准曲线绘制的操作步骤,根据操作步骤建立火焰原子吸收法测定水中铜含量不确定度的数学模型,分别对配制标准使用液、取样过程、样品重复性测定、绘制标准曲线引入的不确定度分量进行了详细的分析和计算,得出扩展不确定度。通过不确定度的计算分析得出绘制标准曲线引入的不确定度分量和样品测量重复性引入的不确定度分量对测量结果产生主要影响,因此,提高方法的灵敏度和准确度的关键步骤是提高操作技能,增加标准曲线测量次数和被测样品测量次数。     

外源物质添加对东北黑土氨基酸矿化的影响

采用间歇淋洗好气培养法研究了东北黑土中氨基酸的矿化过程以及添加葡萄糖和葡萄糖与氮肥配施对其质量分数的影响。结果表明：土壤中氨基酸质量分数的变化受到外源物质添加的影响。与对照处理相比,葡萄糖以及葡萄糖与氮肥配施均能促进土壤氨基酸质量分数的积累,并且2种外源物质对氨基酸质量分数的影响相差不多。土壤不同种类的氨基酸具有不同的矿化特征,其中异亮氨酸的矿化速率最快,其次是赖氨酸、缬氨酸、组氨酸和亮氨酸,而精氨酸、甘氨酸和酪氨酸矿化速率较低。此外,土壤中每种氨基酸矿化对总氨基酸矿化的贡献与其在土壤中的质量分数有关,一般来说,氨基酸质量分数高则其矿化的贡献也大。     

游离亚硝酸对好氧/延长闲置序批式反应器除磷性能的影响

以合成废水为研究对象,在好氧/延长闲置序批式反应器中研究不同浓度游离亚硝酸对系统除磷性能的影响.通过分析闲置期聚磷水解及微生物体内各储能物质的变化及不同反应器的除磷效果,探究其可能存在的影响机理.结果表明,游离亚硝酸浓度为5.13×10-5mg·L-1时对反应器除磷效果及沉降能力抑制不明显,而当游离亚硝酸浓度达到5.13×10-4mg·L-1时,磷的平均去除率降至40.5%,反应器中出现严重的污泥膨胀,污泥沉降指数值最高达310 mL·g-1.典型周期分析表明,游离亚硝酸可影响聚磷菌对碳源的吸收和胞内聚羟基脂肪酸酯的合成,进而影响好氧吸磷及闲置期聚磷水解.恢复试验表明,当游离亚硝酸浓度高于2.57×10-4mg·L-1时,撤销影响后系统的除磷能力和沉降性能虽有明显回升,但无法恢复至初始水平.     

中线式尾矿库洪水漫顶溃坝演化规律模拟研究

为了解中线式尾矿库洪水漫顶溃坝的过程和机理,并提出可行的工程措施,以某中线式尾矿库及下游周边环境为研究对象,采用物理模型试验和数值模拟法对中线式与上游式尾矿库安全性进行对比研究。研究结果表明:由于中线式尾矿库外坝坡堆积粗尾砂的渗透系数偏大,其较上游式尾矿库溃口发展的速率更快,溃坝过程持续时间约14.5 h,坝顶被泄流冲刷形成的溃口宽约289 m,尾矿库下游沟道研究范围内尾矿淤积约871万m3,大量的尾矿仍滞留在库内;采用数值模拟得出的演化趋势与物理模型试验基本一致,但数值模拟计算的尾砂流动速度较快;在拦砂坝下游修建应急拦砂坝工程,物理模型试验表明拦滞尾矿洪水时间约38 min,数值模拟结果表明拦滞尾矿洪水时间约16 min,因此应急拦砂坝措施可有效延长应急逃生时间,减轻溃坝对下游居民的影响。     

Analysis of Environmental and Socio-economic Determinants Affecting Population Longevity Level at County Level in China

Abstract

Based on the current literature, this paper is mainly intended to test whether environmental factors and socio-economic factors will have direct effect on the longevity at county level in China in order to determine the major determinants affecting local longevity level. Using the multi-regression model, we find the result that factors such as temperature, climate, longitude, type of soils, as well as type of agricultural food production play a major role in shaping the longevity at county level, and that socioeconomic factors like infant mortality and gross death rate also have some direct impact on longevity, but the degree of impact is not as strong as the above environmental factors.     

Circulating fluidized bed biological reactor for nutrients removal

A new biological nitrogen removal process, which is named herein “The circulating fluidized bed bioreactor (CFBBR)”, was developed for simultaneous removal of nitrogen and organic matter. This process was composed of an anaerobic bed (Riser), aerobic bed (Downer) and connecting device. Influent and nitrified liquid from the aerobic bed enters the anaerobic bed from the bottom of the anaerobic bed, completing the removal of nitrogen and organic matter. The system performance under the conditions of different inflow loadings and nitrified liquid recirculation rates ranging from 200% to 600% was examined. From a technical and economic point of view, the optimum nitrified liquid recirculation ratewas 400%. With a shortest total retention time of 2.5 h (0.8 h in the anaerobic bed and 1.5 h in the aerobic bed) and a nitrified liquid recirculation rate of 400% based on the influent flow rate, the average removal efficiencies of total nitrogen (TN) and soluble chemical oxygen demand (SCOD) were found to be 88% and 95%, respectively. The average effluent concentrations of TN and SCOD were 3.5 mg/L and 16 mg/L, respectively. The volatile suspended solid (VSS) concentration, nitrification rate and denitrification rate in the system were less than 1.0 g/L, 0.026-0.1 g NH₄ ⁺-N/g VSS·d, and 0.016–0.074 g NO_x ⁻-N/g VSS·d, respectively. __________ Translated from Environmental Engineering, 2007, 25(6): 2, 7–10 [译自: 环境工程]     

氯乙烯储罐注水堵漏腐蚀风险的预测方法研究*

为更好地解决氯乙烯储罐注水堵漏可能导致储罐发生腐蚀泄漏的实际问题,提出1种基于ASPEN和神经网络的氯乙烯储罐注水堵漏腐蚀风险的预测方法。运用ASPEN流程模拟软件,对氯乙烯储罐注水堵漏工艺进行模拟,得到不同泄漏孔径下注水速率和HCl浓度的关系;以HCl浓度作为导致腐蚀的主要影响因素,对不同种钢材进行挂片腐蚀实验;结合神经网络分析,得出HCl浓度与腐蚀速率之间的拟合式,预测储罐腐蚀情况。结果表明:神经网络预测结果平均相对误差7.63%,随注水速率的提高,HCl浓度变化呈下降趋势,腐蚀速率变化呈下降趋势;在等效泄漏孔径24 mm、注水速率0.87 m/s时,Q345R腐蚀速率13.93 mm/a,20#腐蚀速率10.48 mm/a,201不锈钢腐蚀速率7.09 mm/a为3者中最低,但此工况下,201不锈钢有点蚀倾向,储罐易发生穿孔,故201不锈钢不宜用作氯乙烯储罐母材,并提出对《石油化工企业设计防火标准(2018年版)》的修订建议。     

中国“厕所革命”的现状、问题及其对策思考

"厕所革命"是涉及厕所污染物的收集、贮存、运输、处理、处置、利用等过程的生态链工程,强调物质、能量系统、污染物处理、污水回用的闭路循环,已成为我国乡村振兴、旅游发展、智能化产业战略的重要组成部分;目前,全世界范围内厕所卫生状况不容乐观,特别是一些农村地区和欠发达地区。在充分研究国内外"厕所革命"现状的基础上,结合我国国情以及未来发展规划,深入分析目前我国卫生厕所所面临的各种问题和挑战,并提出相对应的对策。     

Hydrogels for the removal of the methylene blue dye from wastewater: a review

Environmental Chemistry Letters - Water pollution is a major environmental issue with the rapid development of industry. Therefore, advanced technologies and materials are needed to remove...