固体碳源生物膜处理地下水硝酸盐污染的脱氮性能研究

采用聚己内酯(PCL)为固体碳源和生物膜载体,研究填充率和水力停留时间(HRT)对生物膜反应器脱氮的影响。结果表明:(1)40%(体积分数)的填充率较合适,4h为最佳HRT。此时反应器硝酸盐氮去除率为88%,出水硝酸盐氮质量浓度平均值为8.80mg/L。(2)丛毛单胞菌属(Comamonas)、热单胞菌属(Thermomonas)、固氮螺菌属(Azospira)和长绳菌属(Longilinea)为反应器的主要菌属,且填充率40%的反应器以上菌属相对丰度总和最高(70%)。     

PM2.5中典型水溶性离子在线观测标准曲线优化研究

为了研究在线离子色谱法测定大气PM2.5中NH4^+、NO3^-、SO4^2-的不确定性来源,探讨了标准曲线的浓度范围及浓度梯度设置对离子浓度结果的影响,并对标准曲线设定方案进行了优化。结果表明:不同浓度范围的标准曲线对于NH4+的浓度结果有较大的影响,存在1. 87%~14. 91%的偏差,对于NO3^-、SO4^2-的影响较小,相对偏差分别为2. 94%和2. 82%;非均匀布点和均匀布点标准曲线定量NH4+的结果存在4. 15%~4. 25%的偏差,对于NO3^-和SO4^2-,相对偏差分别为0. 10%和5. 99%。对于二次拟合的NH4^+,在样品浓度波动较大时,可以将样品划分为低浓度范围和高浓度范围,分别选用低浓度段标准曲线和高浓度段标准曲线,以期得到更合理的浓度结果。     

基于平衡坡降原理的膏体尾矿堆积坡度测算方法

为准确测算尾矿膏体排放的堆积坡度,在已有研究的基础上,分析了膏体坡面明渠流动的自适应变化过程,提出膏体恒定均匀流动时的平衡坡降等同堆积坡度。研究平衡坡降状态下,明渠流动断面、临界流速以及阻力系数的确定方法,建立堆积坡度测算的基本流程和方法。以某铜矿为背景,测算不同质量分数及排放流量条件下膏体的堆积坡度,结果表明:流量一定,质量分数越高堆积坡度越大;质量分数一定,排放流量越大堆积坡度越小;推荐该矿排放质量分数70%,排量150 m3/h,此时堆积坡度为5.34%,尾矿库占地面积较原湿式排放降低27%。     

氧化铜活化过硫酸盐的界面反应机理

本文以苯酚为降解对象,系统性研究了氧化铜(CuO)活化过二硫酸盐(PDS)与过一硫酸盐(PMS)降解苯酚的界面反应机理.结果表明,CuO可高效活化PDS和PMS降解苯酚,电子顺磁共振(EPR)结果表明CuO/PDS体系中的活性物种有SO_4~(·-)、·OH和O_2~(·-),而CuO/PMS体系中主要存在O_~(·-)和~1O_2,猝灭实验结果表明CuO/PMS体系中O_2~(·-)起到了关键作用. CuO/PDS和CuO/PMS体系均可选择性降解具有给电子官能团的有机物.在CuO/PDS体系中,主要活化机理为富电子有机物通过取代表面羟基吸附于CuO表面,与CuO发生电子传递产生苯氧自由基,进一步可活化PDS和O_2产生SO_4~(·-)、·OH、O_2~(·-)等活性物种实现对有机物的降解.而在CuO/PMS体系中,PMS通过取代CuO表面羟基产生亚稳态中间体,与PMS及O_2~(·-)反应生成~1O_2实现对苯酚的降解,虽然体系中也存在与CuO/PDS体系中类似的苯氧自由基活化过程,但其对有机物降解的贡献较小.     

钻井废液的超临界水氧化处理及动力学分析

在反应温度为500～600℃、压力为25～30 MPa、停留时间为30～600 s的条件下,在连续式反应器中研究了钻井废液的超临界水氧化反应.结果表明:钻井废液的COD去除率可达90.00%以上;在600℃、停留时间为600 s时,钻井废液氧化后,剩余收集液的COD＜120 mg/L,满足《污水综合排放标准》(GB 8978-1996)中的二级标准.用幂函数方程描述了氧化剂过量时钻井废液超临界水氧化的反应动力学规律,反应速率常数与温度的关系符合Arrhenius公式,随停留时间的增加、温度的升高,有机物的去除率显著增加;反应速率常数随压力升高而增加,但反应速率常数的增幅随压力的升高而减小,反应活化体积不是常数.在25 MPa时,反应活化能和频率因子分别为(17 745.430 40±1 114.983 42)kJ/mol和1.152 3×10-4s-1模型计算值与实验值的误差在±15%以内.     

Modeling of spatial and temporal variations of ozone-NOx-VOC sensitivity based on photochemical indicators in China

Comprehensive air quality model with extensions (CAMx)-decoupled direct method (DDM) was used to simulate ozone-NO_x-VOCs sensitivity of for May–November in 2016–2018 in China. Based on the relationship between the simulated ozone (O₃) sensitivity values and the ratio of formaldehyde (HCHO) to NO₂ (FNR) and the ratio of production rate of hydrogen peroxide (H₂O₂) to production rate of nitric acid (HNO₃) ($P_{{\mathrm{H}}_2{\mathrm{O}}_2}/P_{\text{HN}{\mathrm{O}}_3}$), the localized range of FNR and $P_{{\mathrm{H}}_2{\mathrm{O}}_2}/P_{\text{HN}{\mathrm{O}}_3}$ thresholds in different regions in China were obtained. The overall simulated FNR values are about 1.640–2.520, and $P_{{\mathrm{H}}_2{\mathrm{O}}_2}/P_{\text{HN}{\mathrm{O}}_3}$ values are about 0.540–0.830 for the transition regime. Model simulated O₃ sensitivities or region specific FNR or $P_{{\mathrm{H}}_2{\mathrm{O}}_2}/P_{\text{HN}{\mathrm{O}}_3}$ thresholds should be applied to ensure the accurate local O₃ sensitivity regimes. Using the tropospheric column FNR values from ozone monitoring instrument (OMI) satellite data as an indicator with the simulated threshold values, the spatial distributions of O₃ formation regimes in China are determined. The O₃ sensitivity regimes from eastern to central China are gradually from VOC-limited, transition to NO_x-limited spatially, and moving toward to transition or NO_x-limited regime from 2005 to 2019 temporally.     

中亚五国气溶胶光学厚度时空分布特征研究

气溶胶时空变化是影响气溶胶气候效应不确定性的主要因素之一.在生态环境脆弱的中亚五国(哈萨克斯坦、乌兹别克斯坦、土库曼斯坦、吉尔吉斯斯坦和塔吉克斯坦)研究气溶胶光学厚度(Aerosol Optical Depth,AOD)的时空变化对中亚地区及全球生态环境和气候变化具有重要意义.基于2002-2019年MODIS 04_...     

Effect of Mn2+ on the phosphorus removal and bioflocculation under anoxic condition

Manganese ion (Mn²⁺) generated from metallurgical, steel making and chemical industries enters sewage treatment plants and affects the sludge activity and flocculation. The effect of Mn²⁺ on the removal of chemical oxygen demand (COD) and total phosphorus (TP) and sludge activity were investigated in anoxic zone of an anaerobic/anoxic/oxic (A²O) process. The compositions and structures of extracellular polymeric substances (EPS) were characterized using three-dimensional excitation emission matrix fluorescence spectroscopy (3D-EEM), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR) to reveal the relationship among Mn²⁺, EPS and sludge flocculation.The results showed that low concentration of Mn²⁺ (<5 mg/L) improved removal efficiencies of COD and TP and increased the activity of alkaline phosphatase, acid phosphatase and dehydrogenase. Meanwhile, the addition of Mn²⁺ increased total EPS, sludge contact angle, Zeta potential and sludge particle size, and thus enhanced sludge flocculation. However, high concentration of Mn²⁺ (>10 mg/L) hindered microbial flocculation and reduced removal efficiencies of the pollutants. When Mn²⁺was 5 mg/L, removal efficiencies of COD and TP reached 65% and 90%, respectively. Sludge flocculation was the best and SVI was 70.56 mL/g. The changes of Mn²⁺ concentration caused deviation of groups’ compositions in LB-EPS and TB-EPS, where the main components were always protein (PN) and polysaccharide (PS). The addition of Mn²⁺ resulted in the degradation of humic acids. However, it did not give rise to significant morphology changes of EPS.     

A review on reactive transport model and porosity evolution in the porous media

Environmental Science and Pollution Research - This work comprehensively reviews the equations governing multicomponent flow and reactive transport in porous media on the pore-scale, mesoscale and...     

活动式大罐收气装置及油气混输新工艺的应用

为了解决东营地区油罐每天都向大气排放工业废气，对环境造成污染的问题，研制了“活动式大罐收气装置”新工艺，用于回收联合站储油罐挥发气。该装置通过玻璃钢管线与油罐连接，油罐挥发气沿玻璃钢管线输至机房内气液分离器，分离出气中的水和轻质油，由天然气压缩机加压，经流量计计量后进入油田天然气气管网。该工艺推广后，经监测结果表明，所有采样点总烃含量低于国家标准２．０ｍｇ／ｍ３。目前全油田３０个联合站安装了此设施，每年回收天然气５１２５万ｍ３，轻质油７０００ｔ。