Abstract
A river model for measuring the biodegradability of organic materials was devised simulating the natural aquatic environments. Applying this model, the biodegradabilities of linear alkylate sulfonates (LAS) were determined by the methylene blue method and UV-spectrophotometry
1) LAS added to the concentration of 10ppm has shown to be removed almost completely in twenty days of operation from the water fractions and bottom sludge layers by determination with methylene blue method. The UV-spectrophotometry revealed, however, the residue of about 40% in water fractions and about 25% in bottom sludge lagers even after the experiment. The discrepancy of these biodegradabilities might be due to the difference between the principles of the determination methods.
2) Among the LAS compounds containing alkyl chains in the range from C10 to C14, the substrates having alkyl chains of C10 were degradated most slowly and the compounds with the chains of C14 disappeared most rapidly.
3) LAS compounds having phenyl radicals near the terminal part of the alkyl chains could be decomposed easily. On the contrary, it was difficult to attack them the phenyl radicals were bound to the inner part.
