Model Development for Biotrickling Filter Treatment of Graywater Simulant and Waste Gas. I

A mathematical model was developed to simulate a biotrickling filter capable of simultaneous treatment of graywater simulant and waste gas contaminated with ammonia and hydrogen sulfide. The model accounts for mass transfer of gas phase contaminants into the liquid phase and subsequent transfer into a biofilm where microbial conversions of contaminants are modeled by Monod kinetics. A set of laboratory experiments was conducted to estimate parameters for each of the two components of the model. Separation of parameter estimation both decreased the total number of parameters estimated simultaneously and ensured that each component of the system was adequately represented. Process performance, as predicted by the calibrated model, was compared to results from the operation of bench-scale reactors. The model was capable of accurately predicting contaminant removal and thus was used to make a preliminary assessment on the feasibility of a proposed dual treatment biotrickling filter system. This model is a valuable tool not only to describe and predict process performance, but also to identify relevant design parameters.     

Effect of Biotrickling Filter Operating Parameters on Chlorobenzenes Degradation

In this paper the effect of operating parameters on biotrickling filter performance degrading chlorobenzene and o-dichlorobenzene mixture were studied. The large laboratory scale biofilter, total volume 40 L, filled with inert packing material was used. The biomass adaptation and cultivation were performed in a batch fermentor and were used to inoculate the biotrickling filter. After a starting period, the influence of the substrate load increase, liquid recirculation flow rate, and empty bed retention time on elimination capacity and removal efficiency were found. The most important recirculation liquid parameters were analyzed every day, that is: concentration of metabolites, dissolved organic carbon, nitrate, chloride, and biomass. A good correlation was found between intermediate concentration and the removal efficiency of the biotrickling filter. The measurements of the absorbance, very easy and rapid, can be used as a control parameter of the biofiltration efficiency.     

Model Sensitivity Analysis for Biotrickling Filter Treatment of Graywater Simulant and Waste Gas. II

A detailed sensitivity analysis was conducted to identify key parameters for a biotrickling filter simultaneously treating graywater and waste gas containing ammonia and hydrogen sulfide contaminants. Sampling-based approaches were applied to quantitatively assess the sensitivity of both design and intrinsic model parameters. Specifically, the sensitivity of contaminant removal rates under system conditions was investigated. Results suggested that contaminant removal rates can be substantially improved by increasing the fraction of wetted area in a biotrickling filter. Although recirculation flow rate is insensitive when considering liquid contaminant removal, increasing this parameter improves gas removal efficiency and also increases wetted area within the biotrickling filter. Reactor performance can also be improved by increasing gas and liquid residence times. Contaminant diffusivity through the biofilm is an important parameter and should be accurately assessed. This study differentiated key from insignificant biotrickling filter reactor design parameters for the biotrickling filter and provides guidance for similar research applications.     

Behavior of Field-Scale Biotrickling Filter under Nonsteady State Conditions

The performance of a field-scale biotrickling filter was investigated for the treatment of styrene vapors released from a bathtub manufacturing process. The two-stage biotrickling filter was operated in series with an average gas flow rate of 350 m3?h?1 corresponding to an overall empty bed gas contact time of 84 s. Daily average values of styrene removal efficiency varied from 40 to 90% with inlet concentrations ranging between 0.4 and 1.7 g?m?3. System performance was not significantly affected by changes in temperature and was moderately susceptible to 3-day starvation or complete system shutdown. After 7 months of styrene treatment, toluene contaminated air was fed to the system and experiments were performed in which styrene and toluene were fed alternately at 3-h intervals. While styrene elimination remained unchanged over the cycles, the elimination capacity of toluene increased with the number of cycles, indicating some adaptation of the process culture to the new contaminant. Overall, the results suggest that biotrickling filters for air pollution control can be successful even under greatly varying operating conditions.     

有色金属冶炼废渣综合治理

本文简要叙述了葫芦岛锌厂竖罐蒸馏残渣、湿法炼锌浸出渣、煤气发生炉渣及精馏过程产出的铝铁锌渣的综合利用情况。     

矿渣钢渣复合微粉技术

随着国家对冶金固体废弃物循环再利用的力度不断加大,对冶金废物再利用的研究也在不断深入。文章阐述了冶金行业固体废弃物矿渣、钢铁渣的利用,分析了钢渣矿渣复合微粉的化学成份和矿物组成,并对复合微粉的易磨性、安定性、活性进行定性、定量分析,做了水泥参合试验,实验证明矿渣、钢铁渣可以充分利用,现已进行工业生产,降低水泥生产成本。     

陶瓷膜过滤器在连铸废水处理中的应用

根据钢铁企业炼钢连铸机二冷水对水质的要求,在某工程的净化浊环水处理系统的过滤设施改造和设计中经过方案比选采用陶瓷膜过滤器代替传统砂滤器。工程实践证明:采用陶瓷膜过滤器处理后的出水水质较好,运行成本低、操作维修方便,减少连铸机二冷喷嘴的堵塞机率,提高喷嘴使用寿命,该设备可以广泛应用于连铸机净化浊环水处理系统中。     

Processing Converter Slags with Total Utilization of All Components

Metallurgist - Currently, almost all plants converted to autogenous smelting of copper-containing concentrates use flotation of converter slags (CS) while leaving 0.55–0.90% Cu in tailings...     

利用钢渣、炼铁除尘灰生产氧化锌

文章介绍了以钢铁生产中产生的固废冶金渣及收尘系统产生的尘灰为原料,通过回收其中的有用成份锌,实现了对固体废物的资源化和综合利用的方法和工艺,产生了良好的经济效益,减轻了环境污染。     

精炼渣系的发泡性能

针对CaO－MgO－Al₂O₃、SiO₂－CaF₂五元精炼渣系进行了有关发泡性能的实验.实验结果表明：（1）随着吹气量的增加,炉渣相对发泡高度相应增加,两者之间存在着较好的线性关系;（2）当炉渣碱度<2.5时,炉渣中MgO质量分数在11%左右对炉渣发泡有利,而在高碱度操作时MgO质量分数则应该低一些;（3）对于低碱度渣,控制Al₂O₃为15%;（MgO）＋（Al₂O₃）为20%～26%较好;（4）炉渣碱度对发泡性能的影响比较复杂,在特定的MgO,Al₂O₃,CaF₂成分范围内,炉渣碱度B在1.9左右发泡性能最好.     

Water Vapour Solubility in Tundish Slags

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熔渣中氧传递机理的研究

介绍了熔渣中氧的扩散系数以及气-渣、气-渣-金及渣-金体系中氧的传递现象,分析了电子电导对熔渣中氧传递的影响,总结了熔渣中氧的传递机理,并认为改变电化学因素可以控制渣相中氧离子的迁移。     

Stabilization of Ladle-Treatment Slags in Steel Production

Ladle-treatment slags are primary wastes from steel production. Slag utilization is prevented by its spontaneous decomposition as a result of polymorphic transformation of dicalcium silicate with decrease in slag temperature. At OOO NLMK-Kaluga, the slag is stabilized by the introduction of boron oxide in the high–magnesia flux during ladle treatment. Industrial tests indicate stabilization of the slag and the formation of a protective layer on the lining, preventing slag corrosion.     

Li_2O对低氧化性钢包渣改性处理的实验研究

通过模拟低氧化性钢包渣组成 ,采用CaO -SiO2 -Fe2 O3-MnO2 (2 % ) -MgO(6 % ) -P2 O5(3 % )系熔剂 ,在CaO/SiO2 ≤ 2 .5 ,Fe2 O3≤ 5 %的范围内 ,用Li2 O替代熔剂中CaO ,测定Li2 O对熔剂熔点和熔剂控制钢液回磷能力的影响