| Rotary drums The "Dano" drum was developed by Dano Ltd. in Denmark about 1933 for composting refuse. The reactor is a rotating drum and it is slightly inclined from the horizontal, 2 to 4 meters in diameter and up to 45 meters long. The drum is kept about 70 % full of refuse and rotates at 0.2 to 2 rpm. |
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As the drum rotates, the waste move in a helical path towards the outlet at teh end of the drum and are mixed and granulated by abrasion. Typical digestion is 1 to 3 days in the drum and is usually followed by screening and static pile curing (see windrow turner). Water and nutrients can be added to the drum and forced aeration is usually provided. |
| The rotary drum has become one of the most popular reactor processes for municipal solid wastes, with several hundred installations worldwide. |  |
