Freeman, the Dallas-based exhibition services giant, has recycled more than 1 million square yards of used aisle carpet as part of a pilot program begun last July. The trade show carpet will be made into drainage pipes for septic systems. Among Freeman's other green steps: signs mounted on pre-used materials such as PVC, natural gas fuel used for forklifts and other vehicles, and use of sustainable products such as biodegradable wastebasket liners.