An option of curation is to configure tasks to run in workflow. There is an optional queueing feature to the workflow configuration. It is documented in the workflow-curation.xml, but not in the documentation manual for DSpace. It works much the same as the rest of the workflow curation, but there is an optional attribute, queue, to the flowstep tag in the workflow-curation.xml. The value assigned to the queue attribute should be the name of the directory where the queue for that flowstep will appear. By default, it is configured from the point of ctqueues.
If a queue is configured for that flowstep, the submission will remain in workflow until the queue has been curated, and the item has passed that flowstep.