The rate of aeration needed to achieve this is about half of the BOD production. The higher the level, the more complete the mixing and the higher the percentage of aerobic decomposition. Table 1 summarizes this information for different livestock species. It pumps liquid laterally about 1.5 m below the liquid surface, and forces air through an aspiration tube at the point of pump discharge. It consists of a continuous open channel, or raceway, under a slatted floor.
Manure is kept moving down one side of the channel and back the other.
Air is mixed into the manure by an aeration rotor. This system is not common in Ontario, mainly because of high cost to install and the more serious consequences of potential foaming. Floating propeller-type surface aerator. Let's consider a feeder pig operation housing 800 pigs. Annual repair costs could be in the order of 10 percent of the initial cost.