Retin-A (tretinoin) is a form of vitamin A that helps the skin renew itself. The Retin-A and Avita brands of tretinoin are used to treat acne. The Renova brand of tretinoin is used to reduce the appearance of fine wrinkles and mottled skin discoloration, and to make rough facial skin feel smoother. Retin-A may also be used for purposes not listed in this medication guide.
Waste Stream. The total flow of solid waste from homes, businesses, institutions, and manufacturing plants that is recycled, burned, or disposed of in landfills, or segments thereof such as the residential waste stream or the recyclable waste stream..
In modern plumbing, a drain-waste-vent (or DWV) is part of a system that removes sewage and greywater from a building, and regulates air pressure in the waste-system pipes to aid free flow.