OPTIMIZATION OF REGIONAL ADVANCED DRINKING WATER TREATMENT SYSTEM BASED ON THE CHARACTERIZATION OF HUMIC SUBSTANCES

本研究旨在从含有腐殖质特性的原水到区域，制定深度饮用水处理系统的优化程序。通过对水生腐殖质的吸附、改性天然材料、氧化和生物处理等方法对腐殖质进行了表征。具体结论如下：(1)米纳加水库腐殖质具有疏水性、分子结构和大小的特征。臭氧氧化后的生物处理减少了疏水性有机物，增加了不可生物降解有机物。反复臭氧氧化/高级氧化-生物处理可去除水中腐殖质。(2)以菲律宾产辣木种子为原料，研制了新型混凝剂。开发了一种简单的纯化工艺，该混凝剂的性能与工业上的相近。以萃取物中的网状结构物质为基础进行混凝处理。(3)在广岛市水岸水库建立了常规饮用水处理系统--活性碳处理-臭氧氧化的中试装置，研究了水生腐殖质的行为。低分子水生腐殖质和水中钙降低了活性碳对痕量有机物的吸附能力。然而，即使在生物活性碳中，也需要5年以上的时间才能达到饱和，表明稳定的去除。

This study was carried out to develop optimization procedure for advanced drinking water treatment system from raw water containing humic substances characteristic to regions. Aquatic humic substances were characterized based on adsorption to activated carbon, modified natural materials, oxidation, and biological treatment. Specific conclusions are as follows ;(1) Humic substances in Minaga Reservoir were characterized by hydrophobicity, molecular structure and size. Ozonation followed by biological treatment reduced hydrophobic organics and increased non-biodegradable organics. Repeated ozonation/advanced oxidation followed by biological treatment could remove humic substances in water.(2) New coagulant was developed from seeds of Moringa oleifera produced in Philippines. Simple purification procedure was developed and the coagulant showed similar performance as those in commercial ones. The coagulation was based on the net-structured substances in the extract.(3) A pilot plant with conventional drinking water treatment system followed by activated carbon treatment and ozonation was constructed in Minaga Reservoir, Hiroshima, and behavior of aquatic humic substances was studied. Low molecular aquatic humic substances and calcium in water reduced adsorption capacity of trace organic substances by activated carbon. However, it took more than 5 years for saturation indicating stable removal even in biological activated carbon.