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

研究了非离子型有机聚合物（NOP）对高岭石粘土悬浮液的絮凝和直接过滤效果。在研究的前半部分，进行了一些罐子试验，以考察NOP对高岭石粘土悬浮液絮凝的影响。这些罐子测试的结果可以总结如下。1)在悬浮液中加入三种（阳离子、阴离子和非离子）有机聚合物中的一种或两种，在任何罐子试验中都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大致相同的浊度去除效果。粒子zeta电位的平均值也没有显著差异。3)每次进行罐子试验时，在烧杯底部都发现了一些絮凝程度很大的颗粒。这些絮团颗粒的密度比仅使用PAC时高5至10倍。在研究的后半部分，进行了带NOP和不带NOP的PAC直接过滤实验。得到了以下结果：1)在直接过滤中，NOP效果显著。2)随着NOP投加量的增加，滤水水头损失增大，滤水浊度降低，这是由于滤层上部去除了较多的絮凝颗粒。3)采用双层过滤器（上层为无烟煤过滤器，下层为硅砂过滤器）直接过滤时，由于絮团颗粒深入滤层，大大抑制了水头损失的发展。4)以上结果表明，与常规过滤相比，采用PAC + NOP对双层过滤器进行直接过滤是非常有用的。

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.