Before the passage of the Federal Water Pollution Control Act (FWPCA) in 1972, sludge management was viewed primarily as a problem of dewatering and physical removal of sewage treatment plant residues. There was little concern with the broader implications of processing alternatives and disposal options. With the enactment of FWPCA, planning for sludge disposal became a required part of general wastewater treatment facility planning. In the ensuing years, planners have become increasingly aware that sludge management is a technically difficult and very costly element in controlling water pollution.