source images:
http://www.zerowaste.lacity.org/site/images/existing_facilities/CD%20Matl1.jpg
http://willyloman.files.wordpress.com/2009/08/debris_trucks1.jpg
http://www.momentousins.com/blog/wp-content/uploads/2012/05/iStock_000000542191Medium.jpg
http://www.fs.usda.gov/Internet/FSE_MEDIA/stelprdb5227101.jpg