Federal and state environmental regulations, coupled with rising energy and waste disposal costs, have prompted many industrial plants to install waste-to-energy conversion systems to dispose of liquid and solid wastes. Properly selected and operated incinerators, when matched with efficient heat-recovery equipment, can provide an effective, economical solution to complex waste disposal problems. Energy can be recovered in the form of steam, hot water, or heated air; and the resulting savings in energy and waste disposal costs can pay for the equipment in a relatively short time. This article discusses basic design, economical, and environmental control considerations for such systems, including incinerator technology, waste characterization, energy requirements, and others.