Degradation of Phenolic Compounds in Creosote Treated Wood Waste by A Mixed Microbial Culture Augmented with Cellulolytic- Thermophilic Actinomaycets Thermobifida fusca

Abstract

Creosote is used for preservation of railway ties and timbers, electric utility poles, marine and foundation piling, fences and garden furniture. Creosote-treated wood waste may cause potential contamination of soil and water if they are not disposed properly. Creosote contains over 300 organic compounds including polycyclic aromatic hydrocarbons, pheno-lic compounds and heterocyclic organic compounds, many of which are toxic to human and can cause damage to kidney, liver, eyes and skin. The feasibility of using a composting technique inoculated with the cellulose degrading actinomy-cetes Thermobifida fusca as a mesophilic/thermophilic bioremediation option to degrade phenolic compounds in creo-sote treated wood waste was evaluated. The temperature profile of bioremediation process clearly identified mesophilic and thermophilic phases in both experiments. Different degradation rates were observed in the mesophilic and thermo-philic phases. Fluctuations of pH was observed in both experiment as the result of the breakdown of organic nitrogen to ammonium in the first week and the formation of organic acids and the loss of ammonium with the exhaust gases in the latter stage. The moisture content decreased in both trials because of the net loss of water with the exhaust gas. Both experiments achieved similar reductions in total carbon and TKN, volatile solids and phenolic compounds, cellulose and lignin indicating similar levels of microbial activities during the composting process. The stability and maturity of the final products were also similar. The inoculation of the cellu-lolytic-thermophilicactinomycetes Thermobifida fusca did not manifest observable differences in degrading cellulose, lignin and phenolic compounds compared with the con-trol.