EFFECT OF PETROCHEMICAL STRUCTURE ON METHANE FERMENTATION TOXICITY.

Wastewaters from petrochemical plants are commonly treated by energy intensive aerobic processes. Anaerobic digestion of such wastes would not only result in saving energy, but would also produce methane gas which could be utilized as fuel. The paper reports on a study to evaluate the effect of molecular structure on toxicity to methane fermentation. Fifty-two petrochemicals were assayed. Toxicity to unacclimated methane cultures developed on acetate substrate was assayed. The results showed definite correlations of molecular structure and toxicity. Chloro substitution, aldehydes, double bonds and benzene rings exhibited toxicity to unacclimated cultures. The addition of hydroxyl groups and increased carbon chain length decreased the toxicities. Acclimation to a toxic compound substantially reduced its toxicity in the case of aldehydes, double bonds and benzene rings.