Environmental engineering: Energy value of replacing waste disposal with resource recovery

Although in the past, environmental engineering has been primarily concerne d with waste disposal, the focus of the field is now shifting toward viewin g wastes as potential resources. Because reclamation usually consumes Less energy than producing new materials, increasing reclamation not only reduce s pollution but saves energy. Technological innovations contributing to thi s shift are summarized here, and are variously classified as emerging techn ologies or research topics, as either new departures or incremental improve ments, and as opportunistic innovations, or examples of a unifying strategy . Both liquid and solid waste examples are given, such as a recent discover y of effects in disinfecting microfiltered reclaimed wastewater with ultrav iolet light. In addition to its value in reducing pollution and conserving energy, this reorientation of environmental engineering could contribute to a more general shift toward greater cooperation among organizations dealin g with the environment.