Abstract
The Biodegradation test method of anionic surfactants was established in 1967 and revised in 1968 as JIS K-3363. This method is only applicable to synthetic detergents primarily composed of alkyl benzene self onates, alkyl sulfate, alkyl polyoxyethylene ether sulfate, alkane sulf ovate and alkenyl self ovate. Establishment of the test method for nonionic surfactants was also desired at that time and is now under progress by the Biodegradation Sub-committee of the Society.
This report covers present situation developed in the past two years in our sub-committee as interim report
Biodegradation of several typical nonionic surfactants such as nonyl-phenol ethoxylate, lauryl alcohol ethoxylate, lauroyl di-ethanol amide, nonyl-phenol polypropylene ether as well as dodecene-1 derived LAS as a standard sample, was evaluated by physical and chemical analysis using shake culture and semi-continuous procedure.
Test results indicate that polyoxyethylene group is degradable as shown by foam reduction, cobalt thiocyanate method and GLC observation of residue.
This may suggest as long as foam pollution is concerned, nonionic surfactants such as nonyl-phenol ethoxylate are biodegradable.
Further study is being conducted to elucidate pathways of degradation in connection with complete degradation.
