TY - BOOK AU - Sandar Cho AU - Visvanathan,C. AU - Hansen,Ian S. AU - Kamei,T. ED - Swiss Government, TI - Influence of organic acid on the flocculation process T2 - Thesis PY - 1995/// CY - Bangkok PB - Asian Institute of Technology KW - Sewage KW - Purification KW - Flocculation N1 - A thesis submitted in partial fulfillment of the requirement for the degree of faster of Science; Thesis (M. Sc.) - Asian Institute of Technology, 1995 N2 - Humic substances, originate from vegetative decay have potential effect on the human health. These substances can react with chlorine in the water treatment and form trihalomethane which pose a threat to human health. The present study has aimed to investigate the influence of humic acids in the flocculation process using alum and Cat-Floe Cl to observe the changes of the floe characteristics of the surface water because of the present of the organic substances. Present of the organic acid has highly influenced on the floe characteristics of the clay suspension. Clay floe forms compact structure, however, humic clay floe was found to be loose structure. Settling velocity of the clay floe was more faster at the present condition of organic matter in the surface water when coagulation-flocculation reaction take place. Humic substances seems to be adsorbed onto the clay particle and reduced its destabilization efficiency. Alum coagulation was effective method for removing of humic substances from natural water. However, Cat-Floe Cl was not effective for both organic removal and floe strength. But Cat-Floe Cl with alum 20 mg/L dose was found to be effective in acidic pH range for both organic removal and floe growth. The optimum pH for organic removal and effective floe growth was found to be around 5.5 UR - http://203.159.5.9/ait-thesis/detail.php?q=B15146 ER -