REMAINING LIFE OF GRANULAR ACTIVATED CARBON FILTER

由于对天然有机化合物和合成有机化合物的严格饮用水标准，颗粒活性炭（GAC）过滤器被用作减轻这种污染的屏障。去除农药和其他合成有机化学品（SOCs）是GAC吸附器的重要处理目标之一。然而在实际应用中，由于背景有机物（BOM）和soc的共存，GAC的设计和操作仍然很复杂。本研究的目的是预测GAC的性能，并确定GAC过滤器的剩余寿命。本研究报告共分6章。第一章讨论了用高压微柱技术快速评价固定床吸附器突破模式的实验方法。根据吸附动力学和平衡公式推导出的基于无因次数的相似规则设计微柱。在相似规则下，微柱与大柱的突破剖面基本一致。观察到的微小差异归因于吸附能力或生物降解的差异。第2章的目的是确定吸附的腐殖质物质如何影响典型合成有机化学品的吸附行为。微柱试验结果表明，当腐殖质存在时，合成有机物的吸附效率明显降低。而腐殖质的吸附效率不受有机合成物的影响。间歇式等温线和柱式等温线研究表明，天然腐殖质预压碳随着腐殖质浓度的增加，其对合成有机化学品的吸附能力降低。辛和二嗪的碳容量的减少比四氯乙烯和四氯化氢显著。预加载活性炭也降低了吸附率。第三章采用微柱技术研究了GAC吸附器对6种不同类型有机农药的吸附性能。水溶性较低的农药具有较高的吸附能力。当腐殖物质作为背景存在时，这种趋势就很明显。第四章采用微柱法研究了预载BOM的颗粒活性炭床对间歇施用农药的去除效果。预加载BOM降低了农药的去除效率。GAC吸附腐殖质越多，对农药的去除率越低。去除率与吸附BOM的量有关，但与农药的浓度无关。采用理想吸附溶液理论（IAST）和颗粒表面扩散的线性驱动力表达式的建模方法充分模拟了这些现象。第五章采用超滤处理过的Kiso河和琵瓦湖水，对4种商用活性炭进行了中试和微柱试验研究。在相同的粒径和SV条件下，对天然有机物的脱除效果几乎相同。手术20个月间断性加药西玛嗪清除效果良好，但亲水性农药阿苏兰出现突破。微柱试验对天然有机物的突破模式与中试植物滤池基本一致，但对农药的突破模式不一致。天然有机物共存下的农药去除对各种GAC粒径和SV可归一化为标准粒径和SV。第六章提出了从多组分组成的角度预测总背景有机物吸附行为的方法。总的有机物被分成几种假想的成分。采用塞流均匀表面扩散模型计算各组分的突破曲线。通过简化的IAST（理想吸附溶液理论）-Freundlich表达式描述的吸附等温线来解释竞争效应。该程序在混凝处理前后对一家夜土处理厂的泥炭水和生物工艺废水进行了验证。少

Due to the strict drinking water standards for hologenated natural organic compounds and synthetic organic compounds, granular activated carbon (GAC) filters are being employed as a barrier to abate such pollution. Removal of pesticides as well as other synthetic organic chemicals (SOCs) is one of the important treatment objectives of GAC adsorbers. In practice, however, the design and operation of GAC remain complicated because of the coexistence of background organic matter (BOM) and SOCs. The objective of this study is to predict GAC performance and to determine remaining life of GAC filter. The research report consists of 6 chapters.The chapter 1 deals with a rapid experimental method for evaluating breakthrough pattern from fixed bed adsorbers by way of a high pressure micro-column technique. The design of micro-column was made on a similarity rule based upon nondimentional number derived from formula of adsorption kinetics and equilibrium. An almost identical breakthrough profile … More is obtainable in the experiments between the micro-column and lager column on the similarity rule. A little discrepancy observed was attributed to a difference of adsorption capacity or biodegradation.The objective of chapter 2 is to determine how adsorbed humic substances affect the adsorption behavior of typical synthetic organic chemicals. From micro column tests, the adsorption effeciency of synthetic organic substances are markedly reduced when humic substances are presented. However the adsorption efficiency of humic substances are not influenced by the presence of synthetic organic chemicals. Batch and column isotherm studies show that preloading carbon with natural humic substances decreases its capacity for a synthetic organic chemicals with increasing the concentration of humic substances. The reduction in carbon capacity for simazine and diazinon is remarkable than tetrachloroethelen and tetrachloride. Preloading activated carbon also reduces adsorption rate.In chapter 3, adsorption capacities of various types of six organic pesticides on GAC adsorber were studied by micro column technique. Pesticides of lower water solubility has higher adsorption capacity. This tendency is pronounced when humic substances are present as background.In chapter 4, the removal efficiency of intermittently applied pesticides by a granular activated carbon bed preloaded with BOM was examined using the micro column test. Preloading with BOM decreased the removal efficiency of the pesticides. The more GAC adsoebs humics, removal efficiency of pesticide decreases. The removal efficiency was a function of the amount of BOM adsorbed, but was unrelated to the influent concentration of the pesticide. A modeling approach employing the Ideal Adsorbed Solution Theory (IAST) and a linear-driving force expression for intraparticle surface diffusion adequately simulated these phenomena.In chapter 5, pilot plant and micro column test studies for 4 commercial GACs were conducted using ultrafiltration treated water of Kiso river and Lake Biwa. Almost identical breakthrough performances for natural organics removal were observed when their particle size and SV were the same. Intermittently spiked simazine during 20 months operation were well removed but hydrophilic pesticide, asulam, showed breakthrough. For micro column test, almost identical breakthrough patterns to pilot plant filter were obtained for natural organics but not for pesticides. Pesticide removal under the coexistence of natural organics for various GAC particle size and SV can be normalized to an standard particle size and SV.In chapter 6, a procedure to predict the adsorption behavior of the total backgeound organics from a view point of multicomponent composition was presented. The total organics were categorized into a few hypothetical components. The plug flow homogeneous surface diffusion model was used to calculate the breakthrough curve for each component. The competitive effect was accounted for through the adsorption isotherms described by a simplified IAST (Ideal Adsorbed Solution Theory) -Freundlich expression. This procedure was validated for a peat water and biological process effluents of a night soil treatment plant before and after coagulation treatment. Less