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，进行了一些烧杯试验，以检查NOP对高岭土悬浮液的絮凝效果。结果表明：1）三种类型中的一种或两种不能充分去除高岭石粘土（阳离子、阴离子和非离子）的有机聚合物。2）在使用明矾混凝剂（PAC）和作为助凝剂的NOP的烧杯试验中，可以获得与仅使用PAC时大致相同的浊度去除。3）每次烧杯试验时，在烧杯底部均发现一对絮凝颗粒。这些絮凝物颗粒显示出比仅使用PAC时高5至10倍的密度。在研究的后半部分，进行了PAC加NOP和不加NOP的直接过滤试验。结果表明：1）直接过滤时，NOP的去除效果显著; 2）随着NOP投加量的增加，水头损失增大，滤后水浊度降低。3）在采用双层过滤器的直接过滤中，（无烟煤（上层）和硅砂（下层）），随着絮体颗粒深入过滤层，水头损失的发展在很大程度上受到抑制。4）如上所述，与常规过滤相比，使用PAC和NOP的双层过滤器的直接过滤可以被认为是更有用的。

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.