抄録
A method for tertiary treatment of night soil by chlorination with calcium and sodium hypochlorites was studied. Removal of ammonium-nitrogen by hypochlorite was not affected by pH. When an excess of hypochlorite to the break point was added, color and ammonium-nitrogen were completely removed. To eliminate the color, the most effective pH on chlorination was at 1-2. Colored substances in the secondary treated water of night soil, such as humic acid, fulvic acid, hymatomelonic acid, and methanol and water-soluble substances, were easily decolorized by chlorination. Orthophosphate was effectively removed by flocculation at pH 10 or above. Orthophosphate was completely removed by treatment with calcium hypochlorite. But, when sodium hypochlorite was used, calcium hydroxide must be added in order to eliminate orthophosphate. The two-stage pH adjustment method is the most effective for the tertiary treatment of night soil by chlorination.
