Place a large skillet over medium heat, and add sausage. Cook, stirring, until sausage is browned, about 5 minutes. Drain fat, and transfer sausage to slow cooker.
Stir the black beans, onion, celery, green pepper, water, tomato sauce, garlic, thyme, bullion granules, white pepper, cayenne pepper, and bay leaves into the sausage in the slow cooker. Cover, and cook on Low until vegetables are tender, about 6 hours. Remove bay leaves before serving.
