For this case we have the following question:
A disinfectant drum contains 4/5 of its capacity, today 1/3 of the disinfectant it contained has been consumed. What fraction of the capacity of the container has been consumed?
So, we have:
Initial disinfectant content:
of its capacity
Consuming
of disinfectant means:

Thus,
of its capacity was consumed.
Answer:
of its capacity was consumed.