It has a greater ability to remove solids than does unseparated manure. Odor control - Farmers with separators are finding that the total level of odor from the solid and liquid manure storages is less than the level of odor would have been with no separation. To some farmers, this would be one of the most expensive parts of the manure system and it may be hard to justify the purchase. The mechanical systems are working in a material that is hard on machines. Regular maintenance is needed to avoid breakdowns.
Extra space is needed to accommodate the system.
Some of the mechanical units are compact and require very little extra space. Two separate manure handling systems are needed -one for liquid and one for solids. While a farmer may have spreading equipment for the liquids, he may have to hire someone to spread the solids or purchase his own spreading equipment. Some systems have high energy costs to operate. The different systems have widely varying energy needs.