INFLUENCE OF NONIONIC POLYELECTROLYTE ON FLOCCULATION AND DIRECT FILTRATION OF KAOLINITE CLAY SUSPENSION

本研究旨在评价非离子型有机聚合物(NOP)对高岭土悬浮液絮凝和直接过滤的影响。在研究的前半部分，进行了大量的烧杯试验，以考察NOP对高岭土悬浮液的絮凝效果。这些罐子试验的结果可以概括如下：1)在任何将一种或两种(阳离子、阴离子和非离子)有机聚合物加入悬浮液的罐子试验中，不能充分去除高岭石粘土。2)在使用明矾混凝剂(PAC)和NOP作为助凝剂的罐子试验中，可以获得与仅使用PAC时大致相同的浊度去除效果。此外，颗粒Zeta电位的平均值也没有显著差异。3)在每次烧杯试验时，都会在烧杯底部发现几个大量絮凝的颗粒。这些絮体颗粒的密度是单独使用PAC时的5~10倍。在研究的后半部分，进行了PAC加NOP和不加NOP的直接过滤实验。结果表明：1)在直接过滤中，NOP的效果显著。2)随着NOP投加量的增加，由于滤层上部去除了大量的絮体颗粒，水头损失越大，出水浊度越低。3)在采用双层过滤器(无烟煤(上层)和硅砂(下层))的直接过滤中，随着絮体颗粒深入滤层，水头损失的发展在很大程度上得到了抑制。4)如上所述，与常规过滤相比，采用PAC和NOP直接过滤双层滤料具有更大的实用价值。

The purpose ot this research was to evaluate the effect of nonionic type of organic polymer (NOP) on flocculation and direct filtration of kaolinite clay suspension. In the first half of the research, a number of jar tests were conducted to examine the effect of NOP on flocculation of the kaolinite clay suspension. The results of these jar tests may be summarized as follows.1) Sufficient removal of kaolinite clay could not be performed in any jar test in which one or two of three types (cationic, anionic and nonionic) of organic polymers were put into the suspension.2) In the jar test in which alum coagulant (PAC) and NOP as a coagulant aid were used, approximately the same turbidity removal as that in only PAC use could be obtained. Also, no significant difference in the mean value of particle zeta potential could be measured.3) At every time of the jar test, a couple of largely flocculated particles were found at the bottom of a beaker. These floc particles showed 5 to 10 times higher density than that in only PAC use. In the latter half of the research, direct iltration experiments using PAC with or without NOP were made. The following results were obtained.1) In the direct filtration, the remarkable effect of NOP was observed.2) As the dosage of NOP was increasing, the higher head loss developed and the lower turbidity of the filtered water was obtained, because of removing much floc particles at the upper part of the filter layer.3) In the direct filtration adopting the double layers filter (anthracite (the upper layer) and silica sand (the lower layer)), development of the head loss was depressed to a great extent, as floc particles went into the filter layer deeply.4) As the above results have howed, the direct filtration of double layers filter using PAC with NOP can be considered much useful as compared with the conventional filtration.