BIODEGRADATION OF NONIONIC SURFACTANTS AND EFFECTS OF OXIDATIVE PRETREATMENT

The aerobic biodegradability of nonionic, ethoxylated surfactants and model compounds, and the effect of advanced oxidation pretreatment on the biodegradability of the biorefractory surfactants were examined. B ioassays conducted using a mixed microbial seed showed that the linear primary alcohol ethoxylates, the fatty acid ethoxylates, and also pol yethylene glycol were all degradable. The biomineralization of the lin ear secondary alcohol ethoxylate, ethylene oxide/propylene oxide block copolymer, and alkylphenol ethoxylate was observed to be inhibited to varying degrees. Additional bioassays were conducted on model compoun ds to examine the effect of specific structural components oh biodegra dability. Advanced oxidation pretreatment using hydrogen peroxide in c ombination with ozone was highly effective at enhancing the biodegrada bility of both the linear secondary alcohol ethoxylate and the ethylen e oxide/propylene oxide surfactants. Advanced oxidation was not effect ive, however, at enhancing the biodegradability of alkylphenol ethoxyl ate with the oxidant dosages used.