Used creosote-treated wood ties were thermally treated between 250 and 350 °C to recover preservative and upgrade the wood to provide an improved quality biomass for thermochemical processes. With thermal treatments ranging from 250 to 300 °C, the amounts of creosote, mostly consisting of polycyclic aromatic hydrocarbons (PAHs), recovered were from 47 to 79 % of total creosote present in the used ties. Thermal treatment at 350 °C recovered 97 % of total PAH compounds. Larger amounts of PAHs with higher molecular weights (HMWs) and lower vapor pressures (LVP) were recovered at elevated temperatures. Temperature above 300 °C decomposed the wood matrix, with a mass loss ranging between 50 to 63 wt% and produced large amounts of light organics, anhydrosugars, and phenolic compounds that would contaminate the recovered creosote. Our study concluded that thermal treatment ranging between 275 and 300 °C would be preferred to recover preservative for recycling and improve the wood quality,

A two-step thermal process, an initial thermal treatment at mild temperature followed by a fast pyrolysis step, was investigated to recover wood preservatives and produce preservatives-free wood for production of high quality bio-oil from used creosotetreated railroad ties. During the initial thermal treatment at temperature of 280 °C for 10 to 30 min, the treated wood ties underwent a 20-25 % weight loss with energy yield (77-83 %). Energy yield at 280 °C was lower than that at 200 and 250 °C (92-97 %) but higher than that at the 300 °C (64-74 %). Recovery level of creosote at 280 °C was comparable to that at 300 °C. Fast pyrolysis at 450 °C of the 280 °C-treated wood ties produced high amount of levoglucosan and phenolic compounds with a traceable amount (1.7-1.9 % of the total peak area) of creosote compounds.

A two-step thermochemical process combining a thermal desorption at 250–300 °C and a pyrolysis at 500 °C of used creosote-treated wooden railroad ties was carried out to recover preservative and produce a high quality bio-oil and biochar. Under optimal temperature between 280 and 300 °C, high preservative removal efficiency (70–74%) was achieved with a high proportion of polycyclic aromatic hydrocarbons (PAHs, 80–82%) and a large portion of the original wood mass (67–70%) was retained. This thermally treated biomass had higher heating value (HHV; 19.9–20 MJ/kg) than the starting material. The physical properties of the preservative, such as viscosity and density, and its toxic threshold against a common decay basidiomycete fungus were similar to those of commercially available P2-creosote. Pyrolysis of the thermally treated ties produced bio-oils with lower water content and total acid numbers, and a higher amount of lignin-derived compounds than that of untreated ties. Biochars derived from the thermally treated ties contained higher carbon content and lower amount of PAHs than biochars from untreated ties.

Subterranean termites are serious pests of wood in service in much of the world. One of the most popular techniques for monitoring and controlling termites is the use of in-ground monitoring stations. Different cellulosic matrices were evaluated in terms of mass loss, moisture content variation and termite presence, accounting for spatial coordinates and monitoring station conditional variables, including: type of cellulosic matrix, matrix treatment and meteorological conditions, during one year in field conditions, both in Portugal and in the USA. A multivariate redundancy analysis was performed resulting in 60.4% of data variability being explained by the variables considered in this analysis. Spatial variables were responsible for the highest amount of variance observed in the response variables monitored for the termite monitoring stations, followed by the type of cellulosic matrix, from which cellulose and Hevea brasiliensis were the most influential variables. The optimization of termite in-ground monitoring stations should be performed through correct evaluation of termite feeding preferences and decay resistance, in order to choose an adequate bait matrix and a proper bait design. The termite species biology and the geographical location where control programs will be applied should also be taken into account.

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