Product Recovery and Flush Waste Minimization
Often products that remain trapped in process piping are flushed after transfer with a cleaning media or the next product in the campaign.  Disposal methods for the resulting flushed product can range from dumping down the sewer drain to collection for burning as hazardous waste disposal.  Pigging systems help by preventing this unnecessary waste stream from directly entering the environment or pollution from waste processing facilities. 
Every pound or gallon of waste product represents a consumption increase in a natural resource.  Pigging systems conserve natural resources by preventing the generation of product waste.