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

Abstract

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 valueadded 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.

Bacterial and fungal communities and contribution of physicochemical factors during cattle farm waste composting

“…It is known that water is the medium for nutrient transportation and metabolic reactions in microorganisms. Nutrient availability is affected by the water content in the microenvironment of the microbes, especially in the thin liquid layers on particle surfaces (Ghaly, Dave, & Zhang, ). However, no significant correlation between moisture and fungal community composition was obtained in this research, indicating that bacterial communities may be more sensitive to fluctuations in moisture content than fungal communities.…”

Contamination of Soils and Substrates in Horticulture

“…Depending on the source of the wood chips, they may contain toxic chemicals, which pollute soil and ground water. It has been found that some of the recycled waste wood used for making landscape mulch products is contaminated with various chemicals, such as creosote, chromium copper arsenate or lead-based paints used for wood preservation against fungi and insects [83][84][85].…”