In Wisconsin alone, over 150,000 tons of pallets are land-filled each year. They are expensive to dispose of in large quantities. The following companies take these for grinding:
Specialty Pallet and Crate
205 East Street
Boyceville, WI 54725
Consider reusing your pallets instead of disposing them. Pallets can be reused in a wide variety of ways. A little creativity and some time on Pinterest will provide numerous options.