[Answer]-Celery SchedulingError: an integer is required

It just occurred to me what was going on. In my settings file, I had the following line:

BROKER_POOL_LIMIT = os.environ.get('BROKER_POOL_LIMIT', 1)

I should have forced that to be an integer:

BROKER_POOL_LIMIT = int(os.environ.get('BROKER_POOL_LIMIT', 1))