内置渗透墙型生态塘处理农村生活污水的研究

通过在传统的生态塘中增设了一道活性渗透墙而改造成的内置渗透墙型生态塘。结果表明,内置渗透墙型生态塘对生活污水具有良好的处理效果,在水力负荷为0．05～0．1m^3／m^2·d之间时,即水力停留时间在10d～20d时,它对COD的去除率在60％以上,对TN的去除率在50％以上,对TP的去除率在75％以上。大大减轻了后序工艺的负担,减少了后序处理设施。从而缩小了整个生态塘系统的占地面积,节省了基建投资,是一种高效的适合农村生活污水处理的技术。     

Al-Cu双金属体系对活性艳红X-3B的脱色研究

以典型偶氮染料活性艳红X-3B为模型污染物,采用测定染料去除率、TOC去除率、苯胺生成量的方法及添加EDTA的对照试验,考察Al-Cu双金属体系对偶氮染料废水的脱色机理和脱色动力学.结果表明,在近中性条件下处理30min后脱色率就可达到83%左右;处理120min后脱色率高达96.4%,其中约为34%的色度去除是由于活性艳红X-3B被还原为苯胺,约为20%和30%的色度去除是由于铝离子混凝和铝刨花表面吸附.染料废水脱色是一个先大量吸附再进行内电解还原逐步降解的过程,铝离子的絮凝-吸附作用能有效促进色度的去除.脱色反应可视为表观一级反应,提高反应温度可以加快脱色速率.     

酸化污泥膨润土颗粒对染料活性翠蓝的脱色研究

以污泥和膨润土为原料,硫酸为酸化剂制备了酸化污泥膨润土颗粒.对制得的样品进行了比表面积和SEM等表征,并用于染料活性翠蓝的脱色.考察了pH值、投加量、反应时间和反应温度的影响,并进行了方程的拟合,计算了热力学参数(ΔH⁰、ΔS⁰、ΔG)和吸附活化能E_a.结果表明,酸化污泥膨润土颗粒对活性翠蓝的吸附量随温度和初始浓度的增加而增大,吸附等温线符合Langmuir吸附模型,其吸附动力学更适于伪二级动力学方程所述规律,吸附速率大小为313　K>303　K>293　K;吸附活化能较低,为5.52 kJ·mol^-1,说明吸附过程以物理吸附为主.同时ΔH⁰>TΔS⁰和ΔG>0表明整个吸附过程活化焓的影响大于活化熵,且属于非自发反应.     

等离子体协同改性凹凸棒石催化脱除NOx的研究

采用等离子体协同改性凹凸棒石催化脱除NOx,研究了等离子体反应器输入电压和凹凸棒石煅烧温度对NO和NOx脱除率的影响规律.结果表明,当反应器输入电压30kV时,NO和NOx脱除率随等离子体输入电压增加而增大.凹凸棒石煅烧温度对催化活性也具有显著影响,当煅烧温度600℃时,部分凹凸棒石被烧结熔融, NO和NOx脱除率都不高;当煅烧温度为400~600℃时,凹凸棒石活性较高, NO和NOx脱除率可达最大值.本实验条件下最佳工艺参数为等离子体输入电压>30kV, 凹凸棒石煅烧温度为400~600℃,NOx最大脱除率可达89.6%.     

活性嫩黄染料废水的臭氧降解研究

以活性嫩黄X-7G模拟染料废水为研究对象,观察了臭氧氧化过程中染料溶液的pH、电导以及吸光度的变化,利用离子色谱仪对染料溶液中Cl-、SO42-、NO3-和NH4+的生成过程进行了分析。结果表明臭氧对染料的降解符合一级反应动力学,20min内对染料的脱色率达96.7%以上,染料分子中的Cl和S在反应40min后分别有97.2%和73.5%被氧化为Cl-、SO42-,偶氮键被臭氧化为N2,-NH2部分质子化形成NH4+,新生成的NO3-来源于NH4+和其他含N基团的氧化。     

Application of machine learning technique for optimizing roadside design to decrease barrier crash costs,a quantile regression model approach

Introduction: In-transport vehicles often leave the travel lane and encroach onto natural objects on the roadsides. These types of crashes are called run-off the road crashes (ROR). Such crashes accounts for a significant proportion of fatalities and severe crashes. Roadside barrier installation would be warranted if they could reduce the severity of these types of crashes. However, roadside barriers still account for a significant proportion of severe crashes in Wyoming. The impact of the crash severity would be higher if barriers are poorly designed, which could result in override or underride barrier crashes. Several studies have been conducted to identify optimum values of barrier height. However, limited studies have investigated the monetary benefit associated with adjusting the barrier heights to the optimal values. In addition, few studies have been conducted to model barrier crash cost. This is because the crash cost is a heavily skewed distribution, and well-known distributions such as linear or poison models are incapable of capturing the distribution. A semi-parametric distribution such as asymmetric Laplace distribution can be used to account for this type of sparse distribution. Method: Interaction between different predictors were considered in the analysis. Also, to account for exposure effects across various barriers, barrier lengths and traffic volumes were incorporated in the models. This study is conducted by using a novel machine-learning-based cost-benefit optimization to provide an efficient guideline for decision makers. This method was used for predicting barrier crash costs without barrier enhancement. Subsequently the benefit was obtained by optimizing traffic barrier height and recalculating the benefit and cost. The trained model was used for crash cost prediction on barriers with and without crashes. Results: The results of optimization clearly demonstrated the benefit of optimizing the heights of road barriers around the state. Practical Applications: The findings can be utilized by the Wyoming Department of Transportation (WYDOT) to determine the heights of which barriers should be optimized first. Other states can follow the procedure described in this paper to upgrade their roadside barriers.     

污泥屏障氧化缓冲容量与重金属再溶出关系研究

借助微生物厌氧活动特别是硫酸盐还原反应,污泥屏障可用来固定尾矿堆场重金属.针对尾矿风化淋滤形成的酸性采矿废水(AMD)与污泥之间发生的氧化还原反应导致的重金属溶出问题,通过氧化滴定实验研究了不同污泥悬液的氧化缓冲容量及其与重金属浓度的关系.结果表明,污泥悬液的氧化缓冲容量随着悬液固液比的增大略有减小,但随着悬液厌氧培养时间的延长而增加.污泥的氧化缓冲容量主要来自Eh≤-150mV的强烈还原区间,可达氧化缓冲容量的50%以上.氧化滴定过程中发现,当Eh≥-150mV时,Zn首先明显溶出;当Eh≥150mV时,Cu和Pb明显溶出.基于实验结果,建立了污泥屏障在AMD渗流条件下氧化缓冲容量消耗的数学模型.模拟计算结果表明,当AMD水头高度为10m时,厚度2m的污泥屏障经历AMD溶液38787a的渗透氧化,仍可保持原有的强烈还原状态,具备对重金属的固定效果.     

欧盟WEEE指令及其最新进展

本文以欧盟WEEE指令为中心,研究了该指令及其最新进展,对其与贸易壁垒的关系及对我国的影响和启示进行了探讨。     

微波诱导催化剂MnO/MgO的制备及其活性研究

采用均匀沉淀法制备了微波诱导催化剂MnO/MgO,通过实验确定催化剂的制备条件并对催化剂的形貌进行了SEM表征。实验结果表明,在微波功率900 W,微波时间8 min,催化剂投加量0.6 g/L的条件下,利用微波诱导氧化技术处理50 mL浓度为50 mg/L的活性艳蓝,活性艳蓝的脱色率达到了96%,H2O2的加入能提高脱色效率,缩短反应时间。     

酸缓冲容量对污泥屏障重金属再溶出控制研究

借助污泥中的厌氧微生物活动,污泥屏障可用来固定尾矿堆场的重金属.针对尾矿风化淋滤形成的酸性采矿废水(acidmine drainage,AMD)与污泥屏障相互作用,可能会引起已固定重金属再次溶出问题,通过酸滴定实验,研究了不同厌氧培养时间的污泥悬液的酸缓冲容量及其对重金属再溶出的影响.结果表明,污泥悬液酸缓冲容量与悬液固液比成正比,并随着厌氧还原程度的加深而增加.碳酸盐缓冲体系和有机质缓冲体系对污泥悬液酸缓冲有重要意义.酸滴定实验发现,随着pH降至6.2以下,重金属Zn、Pb和Cu开始快速溶解释放,且释放量符合ZnCuPb.基于实验结果,建立了污泥屏障在AMD渗透条件下酸缓冲容量消耗的数学模型.模拟计算结果表明,对于厚度2.0 m的污泥屏障,即使在10.0 m水头的AMD渗透酸化条件下,有效酸缓冲容量经历666 a之后才能被耗尽,在此时间内污泥屏障具备对重金属的生物化学固定能力.