From Table 3.2, the total manure and wasted water produced per AU per day is 6.8 ft3/AU/day. Calculate the manure volume per day as follows: 118.8 AU/building x 6.8 ft3 / AU / day x 7 days = 5655 ft3 of manure/building. Step 3. The volume in gallons is 5655 ft3/day x 7.48 gal/ft3 = 42,299 gal/building.