Each year a large number of wooden pallets are disposed of in US landfills, representing a significant portion of total wood usage. The purpose of this research was to gain an understanding of the numbers of pallets reaching landfills, specifically Municipal Solid Waste (MSW) and Construction & Demolition (C&D) landfills. Also, the research was conducted to determine what, if anything, was done with the pallets once they were received by landfills.Mail questionnaires were sent to every state licensed MSW and C&D landfill identified in the US, except Alaska. Alaska was omitted because it is known to have many small landfills each representing a single small village. It was thought that these small landfills could skew the results. The questionnaire mailed to the landfills was based on a questionnaire used in a Virginia Tech study of landfills in 1995. Only minor changes were made to the previously used questionnaire so that the data collected would be comparable to previous results.This study found that, on average, MSW landfills received 138,000 tons of waste and C&D landfills received 36,000 tons of waste in 1998. This amounted to a total of 239 million tons of waste at MSW facilities and 40 million tons of waste at C&D facilities. Average tipping fees at MSW and C&D landfills were $29.31 and $16.84 per ton, respectively. Pallets represented 2.8 percent of waste at MSW facilities and 3.3 percent of waste at C&D facilities. This amounts to 138 million pallets reaching MSW landfills and 40 million pallets reaching C&D landfills in 1998. Of these pallets reaching landfills 22 million were recovered from MSW landfills and 16 million were recovered from C&D landfills. Recovered pallets from both types of landfills were typically ground and used for mulch, animal bedding, compost or boiler fuel. Infrequently, pallets were used as-is. But this was infrequent. When pallet material was sold by MSW and C&D facilities, it received between ten and twenty dollars per ton depending on end use and region of the country. / Master of Science

Each year a large number of wooden pallets are manufactured, recycled, and disposed of during the transportation of goods throughout the United States. The production of these pallets consumes a significant amount of wood and a large number of pallets also end up in landfills at the end of their useful life cycle. However, these pallets can be recovered through repair, broken apart into components, ground into mulch, fuel, animal bedding, or used by landfills for day to day operations. The purpose of this research was to investigate the total number of pallets and crates reaching landfills in the United States as well as to gain a better understanding of the overall waste stream. This was done by surveying all licensed Municipal Solid Waste (MSW) and Construction and Demolition (CandD) landfills in the continental United States. A questionnaire was sent to these landfills, and this entire study was intended to build upon previous Virginia Tech landfill surveys conducted in 1995 and 1998 with some changes made after careful review. Overall, it was found the average MSW facility in the United States received 185,077 tons of waste and the average CandD facility received 74,911 tons. This results in a total national estimate of 253 million tons of MSW and 76.9 million tons of CandD waste. Approximately 18.3 million pallets were landfilled and an additional 13.8 million were recovered, repurposed, or reused at MSW facilities. At CandD facilities, approximately 19.2 million pallets were landfilled while 38.3 million were recovered. / Master of Science

Wood pallets are heavily used throughout the United States and the World to transport, store, and protect goods. During a lifecycle, pallets typically experience various stresses from warehouse storage racks, materials handling equipment, and floor stacking situations. The components within the pallet interact to withstand load and impact forces. Every year product damage and human injury/death result from improperly designed pallets, non-reliable packaging systems, and careless materials handling methods. In use wood pallets are exposed to a variety of loads and support conditions. This research investigates the effect of different pallet designs and support conditions on pallet stiffness. Uniform loads were applied to pallet designs containing thick or thin components and three, four, or five non-notched and notched stringers. The pallets were supported using racked across the length, racked across the width, fork truck tine, and floor stack support conditions. Structural analysis was used to determine the test loads for each pallet bending test. Pallet deflections were measured in specific locations for each bending test. Pallet test results indicated that heavy duty pallets are 6.5 times stiffer than light duty pallets tested in the racked across width (RAW) support condition. Non-notched pallets tested are 51% stiffer than notched pallets in the racked across length (RAL) support condition. Test results also indicated that a wider fork tine support span decreases average pallet stiffness by 29% and 49% for 4 and 5 stringer pallets, compared to 3 stringer. The heavy duty pallets tested are, on average, 48.3% stiffer than light duty pallets in the fork tine support condition. For the notched fork tine support condition, the average pallet stiffness decreased by 29% and 3% for four and five stringer pallets, compared to three stringer. Pallet joints were tested to measure joint stiffness. Joint rotation tests were conducted to determine rotation modulus and joint withdrawal tests were conducted to determine joint withdrawal stiffness. The joint stiffness measurements were used as spring constants in structural analysis based on semi-rigid joint performance. Heavy duty pallet joints were approximately half as stiff (6758 in-lbs/radian) in rotation as light duty pallet joints (12907 in-lbs/radian). Light duty pallet joints were less stiff (44008 lbs/in) in withdrawal than heavy duty pallet joints (57823 in/lbs). The results from this research were used to compare with results from ANSYS (Version 11) structural model estimates. The average predicted error for all pallet bending tests was 13% (heavy duty) and 3% (light duty). / Master of Science

This study investigates use of the organosilane 3-(trimethoxysilyl) propyldimethyl octadecyl ammonium chloride (Si-Quat) as a wood treatment to impart residual moisture and organism control on wood substrates. Study 1, which utilized experimental testing procedures to evaluate mold growth after standardized heat treatment, indicated less surface mold on treated samples. Study 2, which utilized standardized testing procedures to evaluate Si-Quat treated wood’s resistance to subterranean termite attack, indicated greater termite mortality and less feeding on treated wood, as well as increased termite feeding preference for untreated wood. Study 3, which utilized standardized testing procedures to evaluate water repellency, indicated significantly reduced moisture gain at higher silane-based treatment levels in comparison to untreated wood. It is concluded that a silane based treatment utilized in this study can be effective for organism control and the possible supplementation to current phytosanitation of wood packaging materials.