Biosolids are the organic materials resulting from the physical, chemical, and biological treatment of municipal wastewater (sewage) in order to control odors and remove disease-causing organisms, toxins, and some heavy metals. About 17% of current production is landfilled, but most biosolids are recovered and used (mostly as fertilizer and some to produce energy). It is projected that by 2010, 8.2 million dry tons of biosolids will be generated.