Experiments were conducted in finishing pig houses located in the Veneto Region (Po Valley, Northern Italy). The pig houses, which have fully slatted floor with slurry channels, are cleaned by means of a "vacuum system." On the bottom of the channels, pipe outlets are placed every 10 m2 and connected to a sewerage system. Slurry is discharged by opening a valve in the main slurry pipe, without any mechanical pump; a slight vacuum develops and allows the slurry to flow. Tests were carried out in order to assess the effectiveness of the vacuum system with different slurry levels in the channels (0.15 - 0.40 m) and different channel lengths (40 - 60 m). Discharge times, cleaning efficiency, and sludge settling were studied. Moreover, gaseous emissions (i.e., carbon dioxide, ammonia, methane, nitrous oxide) and odors were monitored before, during, and after the cleaning operations, in order to assess the environmental effects of the technique. Preliminary results show that the vacuum system with slurry levels higher than 0.30 m and once a week slurry removal was effective.
