What does it mean if a water sample has more BOD?
BOD is simply means the amount of oxygen demand to convert the organic waste matter into simpler form ..
now, when the aerobic bacteria will degrade these organic matter into simple form , then they will consume the oxygen and will increase the DO (DEMAND OF OXYGEN )
so, the water sample has more BOD means the water sample is more polluted , as more demand of oxygen refers to more no of aerobic bacteria present and more aerobic bacteria present means more amount of waste matter ..
HOPE IT HELPS