Abstract
The shake culture method was adopted as the Testing Method for Biodegradability of Synthetic Detergent in the Japanese Industrial Standard in April 1967. Japanese Ministry of International Trade & Industry is executing its administrative recommendation toward the change-over to biodegradable detergents. Detergent industry is promoting the change-over by its own initiative prior that recomendation. The authors estimated that the proportion of biodegradable surf actants with straight alkyl chain was ca. 54% of the total anionic surfactants for use of household detergent and that of linear alkylate sulfonates within the alkylbenzene sulfonates used was ca. 38% in the middle of 1967, and that these proportions turned to ca. 61% and 48%, respectively, at the end of 1967.
At that turning stage, determinations of the content of linear alkylate self onates in total of the alkylbenzene sulfonates in raw municipal sewages, effluents from sewage treatment plants, and river waters were carried out in Aug.-Sept., 1967 and Feb.-March, 1968.
It was found that the content of linear alkylate sulfonates were <531% (Aug.-Sept., 1967) and <540% (Feb.-March, 1968). This rather higher figures of some 30 or 40% obtained with river waters indicate the direct discharge of domestic sewage into rivers and necessity for treating the sewage in sewage treatment plants. From those results, it is believed that remarkable effect of the change over is difficult to expect under the present situation, some 120% of pervasion of sewerage systems.
