Some systems have high energy costs to operate. The different systems have widely varying energy needs. Some may require no energy inputs while others may require several kilowatts of power. There is an increased management requirement. An extra step has been added to the manure handling system.
Someone has to take time to make sure the system is operating properly.
Again, this will vary depending on the type of separator. It involves a settling pond or basin. The flow of the liquid is slowed down to a point where solid particles settle. The liquid portion usually spills over or is pumped to a separate storage. A fairly high percentage of solids can be removed from the manure using this system.