Revista de biorremediación y biodegradación

Abstracto

Augmenting Composting Microbial Community with Thermophilic Cellulolytic Organisms for Enhanced Degradation of Phenolic Compoundsin Creosote Treated Wood Waste

Abdel E Ghaly, Deepika Dave and Bopeng Zhang

Creosote is widely used as a wood preservative in railway sleepers, utility poles, bridges, building foundations, fences, stakes for vegetables and fruits, garden furniture and outdoor recreational facilities. Contamination of soil and water and threat to human and animals health are the major constraints to disposal of creosote-treated wood waste. Composting provides a treatment option for creosote-treated wood waste and production of a value- added product. The aim of this study was to test the effectiveness of inoculating the composting process with three thermophilic-cellulolytic microorganisms ( T. curvata , T. aurantiacus and T. fusca ) in degrading phenols in creosote treated wood waste. Used cooking oil was added into the composting system as a bio-available carbon source. The temperature, pH, moisture content, solids, total carbon, nitrogen, phenols, cellulose and lignin were monitored. The temperature profiles showed that the thermophilic phase (>45 ?C) was achieved and successfully maintained due to the addition of used cooking oil. The moisture content decreased because the water produced by microbial respiration did not compensate for the water vapour lost with the exhaust gases. The breakdown of organic nitrogen to ammonium caused an initial increase in the pH which was then decreased due to the formation of organic acids from the decomposition of fats and the loss of ammonia with the exhaust gases. The inoculated experiments achieved higher reductions in volatile solids, total carbon, TKN, phenols, cellulose and lignin compared to the control. Different degradation rates were observed in the psychrophilic, mesophilic and thermophilic stages of composting. The product from the inoculated experiment had improved stability and phytotoxicity compared to that of the control (uninocualted). The inoculation of thermophilic-cellulolytic microorganisms ( T. curvata , T. aurantiacus and T. fusca ) accelerated the composting process and resulted in higher degradation of phenolic compounds, lignocellulose and lignin.