Hydraulic Approach to Flush Systems for Dairy Manure Removal

The following note aims at characterizing the hydraulic behavior of the removing wastes method from alleys through the flush system in dairy freestall barns. The flush system guarantees the moving, the conveyance and the removal of wastes from the alleys flooring, through the passage of the manure flux. The application of an experimental hydraulic approach to the analysis of the manure flux allowed the identification of descriptive parameters of the functioning scheme of the alleys in a freestall barn, localized in the Reggio Emilia in the North of Italy, which has been using this cleaning system since some years. Differences in the quantity and type of solid materials laying on the floor have been found to strongly influence the roughness of the alley and then variation on the velocity values. Velocity measurements collected during flush operations both on the already cleaned alley and on the alley enriched with manure allowed to investigate the Manning’s coefficient variations depending on the manure presence on the alleys. Differences on measured and calculated velocity values obtained through the application of the Chezy formula are attributed to the choice of the Manning coefficient n value equal to 0.02. The calculated velocity values were always less than those measured, giving then an under-estimation of the velocity and then a minor cleaning actions.