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在SBR中对自养环境下短程硝化过程动力学和维持初始DO质量浓度不变的条件下有机物对短程硝化的影响进行研究.结果表明,自养环境下,短程硝化过程动力学可以用Monod模型表示,NH4+-N对污泥的最大比氧化速率vmax为13.05mg·g1·h-1,NH4+-N半饱和常数Ks为21.98 mg·L-1.DO充足的条件下,低浓度有机物对短程硝化作用影响不大,系统中主要反应为短程硝化;高浓度有机环境下,氨氮降解速率略有下降,亚硝氮积累率降幅较大,TN有损失,系统中除了短程硝化外,还发生了同步硝化反硝化作用.动力学参数vmax随着有机物浓度的增加先变大后减小,在C/N体积比为0.6左右时,vmax达到最大值58.72 mg·g-1·h-1. 相似文献
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针对受硝酸盐污染的水源水,建立了以琼脂凝胶为反硝化菌的碳源和微生物载体的反应器,通过生物反硝化作用去除水源水中的硝酸盐.试验结果表明,在水源水自然接种的条件下,通过微生物的驯化培养可以顺利启动琼脂凝胶反应器;系统的反硝化效果受水力停留时间(HRT)和进水DO质量浓度的影响较明显,进水NO3-N质量浓度对系统的反硝化能力有一定的影响,同时改变进水方式可以进一步提高反硝化效率;在温度为21~23℃、进水NO3-N质量浓度为24.74mg·L-1、HRT为7.1 h、进水DO质量浓度不控制的条件下,NO3-N的去除率能达到76.25‰此时出水COD和NO2-N质量浓度分别为16.57mg·L-1和0.387mg·L-1.研究指出,琼脂凝胶生物反硝化系统能够有效地脱除水源水中的硝酸盐氮. 相似文献
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通过SBR短程硝化反硝化同步脱氮除磷工艺处理模拟啤酒生产综合废水,为达到稳定的COD、NH4+-N和TP的去除及NO2--N的积累,对该工艺的影响因素进行了研究.结果表明,工艺的稳定运行是由进水COD、pH、DO、温度和MLSS等因素共同作用的结果,其中控制较低的DO的质量浓度(<0.5 mg·L-1)是实现NO2--N积累的关键因素之一;过低或过高的进水pH、COD均会影响该工艺的正常运行.温度及MLSS含量会影响氨氧化过程与反硝化过程的反应速率,但不是系统稳定运行的决定因素.当DO的质量浓度为0.3~0.5 mg·L-1、进水COD低于1 100 mg· L-1、pH为7.2~8.4,在12~25℃可获得稳定的NO2--N积累. 相似文献
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同步除碳脱氮BAF快速启动中试研究 总被引:1,自引:1,他引:0
为缓解同步除碳脱氮曝气生物滤池(BAF)启动过程中异养菌对硝化菌的抑制作用,提高硝化菌的竞争优势,提出了BAF低强度反冲洗与高浓度硝化污泥接种相结合的启动方法.试验结果表明,通过第一阶段闷曝接种和第二阶段小流量连续进水后,COD去除率达到80%以上,平均出水COD低于50mg·L-1,满足污水排放一级A要求;而NH4+-N去除率仅为20%左右.通过第三阶段的低强度反冲洗与高浓度硝化污泥接种,经过5个周期后,NH4+-N去除率提高至85%以上,出水NH4+N质量浓度低至5mg·L-1以下,满足污水排放一级A标准.该方法能使BAF的启动周期缩短为30d左右,并能够保证其长期稳定运行,平均出水COD和NH4+-N质量浓度分别为35.4mg·L-1和3.48mg·L-1,均能满足污水排放一级A要求. 相似文献
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针对添加剂废水中含有少量乳链菌肽及高含量Cl-的特点,采用“光催化氧化-上流式厌氧污泥床-A/O”组合工艺对废水进行处理.经过5个月的调试,在系统进水COD为12 680 mg·L-1、BOD5为5 213 mg·L-1、NH3-N的质量浓度为121 mg·L-1的情况下,出水COD为97 mg· L-1、BOD5为27 mg· L-1、NH3-N的质量浓度为13 mg·L-1,去除率分别为99.2%、99.5%和89.3%,排水水质达到了GB 8978- 1996规定的第2类污染物最高允许排放一级标准. 相似文献
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洛阳石化PTA废水生物处理系统中活性污泥长期处于膨胀状态,严重影响系统的正常运行.对洛阳石化PTA废水生物处理流程的进水水质、容积负荷、污泥负荷以及氮磷质量浓度、生物相进行调查与分析.结果表明,PTA进水COD在1862-7568mg·L-1,之间,波动幅度很大;一级生化池常超负荷运行,而二级生化池负荷过低,各流程负荷失衡.进水氮组成中主要为NO3-N,质量浓度为80-165mg·L-1,经过一级生化处理后,硝酸盐几乎完全被反硝化,不能被微生物利用;而NH4+-N质量浓度仅25-42mg·L-1,进水磷约0.1-0.3mg·L-1.从C/N/P比来看,微生物生长所需氮磷浓度明显不足,这是引起污泥膨胀的主要原因.上游来水水质不稳定,特别是其中的有机胺类物质(环己胺),对下游生物处理系统造成冲击,并产生严重的跑泥现象. 相似文献
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采用两级UASB-A/O组合工艺处理实际高氨氮城市生活垃圾渗滤液,在获得稳定的有机物与氮同步去除的前提下,重点考察游离氨(FA)与游离亚硝酸(FNA)对短程硝化稳定性的影响。在UASB1中进行反硝化同时产甲烷以去除部分TN和部分COD,在UASB2通过产甲烷进一步去除COD,在A/O反应器中主要实现高氨氮的短程去除和剩余COD的降解。试验共进行104 d,历经短程硝化稳定、破坏和恢复3个阶段。结果表明,当最小FA浓度控制在3.1 mg.L-1以上时,系统可维持稳定的短程硝化,NH+4-N去除率、NO-2-N积累率、TN去除率分别可达到99%、95%和86%。当FA浓度小于0.6 mg.L-1时,在原水碱度充足且过曝气的条件下,仅依靠FA对NOB的抑制作用,难于维持短程硝化,NO-2-N积累率下降到29%。前两阶段的FNA浓度均低于0.011 mg.L-1,没有对NOB起到抑制作用,而在第3阶段,FA浓度仍维持在较低浓度,但系统FNA浓度通过降低pH值而大幅度提高(最大值为0.414 mg.L-1),从而利用FA和FNA的协同抑制作用迅速恢复并维持短程硝化,NO-2-N积累率升高到92%。可见FA与FNA是实现并维持城市生活垃圾渗滤液短程硝化的重要影响因素。 相似文献
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在常规外置MBR的基础上改变曝气方式,变鼓风曝气为间歇射流曝气;优化射流器和循环加压泵组合方式,并将其用于处理模拟生活污水.结果表明,改良后的间歇射流曝气可以代替鼓风机曝气并且提高了充氧效率.进水COD平均为407 mg·L-1,NH3-N、TN平均质量浓度为21.2 mg·L-1和41.5 mg·L-1时,出水COD为11.5~30.7 mg·L-1,去除率为93%~97%;出水NH3-N、TN质量浓度为3.9~10.2 mg·L-1和10.1~17.8 mg·L-1,去除率分别为52.2%~81.5%和57.1%~75.6%. 相似文献
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ONACCURACYOFANALYSISOFOFHYDROGEN1前言我公司目前应用的氢气纯度分析方法有两种,一种是爆炸反应法,另一种是焦性没食子酸吸收法。几年来,人们对两种分析方法的准确性曾有过褒贬不一的评论。这里我们也谈谈自己粗浅的观点。2爆炸法测定氢气纯度一定量的氢气样品与适量的空气之均匀混合物因反应后生成液体水而引起气体体积减少,减少的体积等于参加反应气体体积之和。其中l/3为氧气,2/3为氢气。根据氢气取样量和反应前后混气体体积之差,以及氢气在反应中的体积比例关系,可计算出样品的氢气纯度。计算公式式中:A一混… 相似文献
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P. P. Budnikoff 《Journal of the American Ceramic Society》1924,7(11):817-820
The different analytical methods proposed for the evaluation of gypsum have been subjected to an experimental test. A combination method, consisting of a fusion with KHCO3 and determination of CaO by KMnO4 titration, the SO3 by Andrews method of titration of BaCrO4 has been found to give very reliable results with the least consumption of time. 相似文献
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A model is developed for the sedimentation from a suspension of two particle species of unequal densities and of different sizes. The composition and the thickness of various layers in the sediments are predicted using graphical and analytical methods. The model predictions were in excellent agreement with experimental results, when the particle size ratio was ≥ 108. When size ratio of the particles was 2.60 and 4.31 the agreement occurred in about 50 percent of the cases. 相似文献
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A novel technique serves to monitor instantaneous rates of loss of a volatile solute from a suspended drop during drying. A highly sensitive electron capture detector is used to monitor concentrations of SF6 released into a flowing gas stream from a suspended, drying drop. Simultaneously, the appearance and morphological development of the drop are monitored with a video camera. This provides the wherewithal of relating instantaneous rates of loss of the volatile solute to particular events during the development of particle morphology.
Initial experiments have been carried out with drops of aqueous solutions of glucose, sucrose, maltodextrin and coffee extract. The results clearly display the onset of the volatiles-retentive selective diffusion phenomenon. There is also substantial loss of the volatile component later in the drying process, when the drops undergo repeated ex ansion, bursting and cratering due to the formation of internaf bubbles. These experiments appear to be the first quantitative demonstration of major losses accompanying changes in drop morphology. 相似文献
Initial experiments have been carried out with drops of aqueous solutions of glucose, sucrose, maltodextrin and coffee extract. The results clearly display the onset of the volatiles-retentive selective diffusion phenomenon. There is also substantial loss of the volatile component later in the drying process, when the drops undergo repeated ex ansion, bursting and cratering due to the formation of internaf bubbles. These experiments appear to be the first quantitative demonstration of major losses accompanying changes in drop morphology. 相似文献
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ANALYSIS OF RECENT MEASUREMENTS OF THE VISCOSITY OF GLASSES 总被引:5,自引:0,他引:5
Viscosity of Simple Soda-Silicate 500° to 1400°C Comparison of the results given by English with those of Washburn, Shelton and Libman, indicates a discrepancy in the absolute values of log10 viscosity amounting to 0.6, those of Washburn et al., being relatively too high. If correction for this is made, the isothermal curves of log10 viscosity as a function of soda content are smooth up to 50% Na2O, showing no inflection. The observations as a function of temperature T are all represented within accidental error by an equation of the type where all three constants vary regularly with the composition. Change of Viscosity of Glass (6SiO2, 2Na2O) due to Molecular Substitution of CaO, MgO and Al2O3 for Na2O The effect is clearly brought out by plotting (from the results of English) the change of log10η due to the substitution as a function of temperature. The curves each show a sharp bend at a temperature between 840° and 1050°C, which is designated the aggregation temperature Ta. If we divide these curves by the corresponding percentage substituted, we get curves for each oxide which are straight and parallel below the aggregation temperatures, the slopes (increase of change of log10η per 100°C) being −0.056 (CaO), −0.055 (MgO), −0.018 (A12O3) per per cent oxide substituted. For substitution of 1/2 molecule the slopes are −0.325 (CaO), −0.23 (MgO) and −0.18 (Al2O3) per 100°. At the aggregation temperature the change of log10η per per cent is a minimum, 0.03 to 0.06 for CaO, 0.12 for MgO, 0.07 for Al2O3. Evidence of Aggregation in Glasses, from viscosity Measurements The sharp bends in the plots of change of log10η due to substitution of an oxide for Na2O, suggest the beginning of molecular aggregation at these temperatures. These aggregation temperatures are close to the devitrification temperatures, but the effect on the viscosity curves cannot be due to actual devitrification since it does not change with time. Taking the aggregation temperatures as equal to devitrification temperatures, additional isotherms are roughly sketched into the equilibrium triangle of the system Na2O-CaO-SiO2. Change of Viscosity of Glass (4SiO2, 2Na2O) due to of Substitution of B2O3 for SiO2 The change of log10η (from the results of English) is plotted as a function of temperature, and also the change of log10η per per cent B2O3. The curves are more complex than for the substitution for Na2O. 相似文献
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面对日益激烈的市场竞争,摩托车油箱外观质量越来越成为影响销售的因素之一。文章介绍了改进工艺后的油箱涂装,该涂装体系提高了油箱外观的丰满度,降低了油箱涂装的生产成本。 相似文献
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用两个形状指数表征粉煤灰颗粒形貌的研究 总被引:5,自引:0,他引:5
引用两个形状指数表征颗粒形状的概念,即先将颗粒形状近似为椭圆,再将椭圆图像分离:以圆为基准的颗粒宏观形状指数δ;以光滑椭圆为基准的颗粒轮廓凹凸度,即微观形状指数ζ。分析和发展了近似椭圆模型。并运用图像分析仪对粉煤灰、水泥样品进行实验。结果表明,粉煤灰颗粒的两个形状指数δ和ζ都大于水泥颗粒。证明粉煤灰颗粒的球形度、表面光滑度优于水泥,而且,随着粒径增大,δ和ζ呈下降趋势,表明磨制颗粒越粗。(?)粒形状越不规则。文中还运用近似椭圆模型再现了颗粒的模拟图像。 相似文献