powders of specific particle size, high productivity and versatile applications. By definition, âSpray drying is the transformation of feed from a fluid state into a dried. particulate form by spraying the feed into a hot drying medium.â (Masters, 1991) A spray dryer operates on convection mode.
Sometimes the grounds and maintenance department of a town or county creates mulch from trees that have been cut down and they make it available to the public. To lay a 4-inch-deep spread of bark mulch in a 300-square-foot area, a landscape or garden service will charge $425, which includes the material and labor. You can buy the mulch for $85 and do it yourself, and pocket a 80 percent saving.
1 The cost for this type of mulch is about $10 per 2 cubic feet. 2  Oyster Shells-If you live in an area where oyster shells are readily available, they may be free for the taking. 3  They make a pretty mulch around plants, are semi-permeable and can also be used for paths and walkways. Rubber mulch also comes in a variety of colors to suit anyone's taste. 2  The cost for a bag of black or red rubber mulch is comparable to that of wood chips or nuggets-approximately $12 per 2-cubic feet. 3  Colored rubber mulch, such as purple or yellow, may be a few dollars more.