Answer. The Federal Water Pollution Control Act Amendments of 1972 require adoption of at least secondary treatment and, in some cases, advanced wastewater treatment technologies. Upgrading of municipal sewage treatment to secondary treatment will approximately double the amount of treatment solids (sludge) produced. Incorporaion of advanced wastewater treatment technology (tertiary treatment) can effectively double or even quadruple the amount of sludge produced by secondary treatment. It has been estimated that the U.S. currently generates about five million dry tons (100 liquid tons) of sewage sludge. This generation is expected to approach twelve million dry tons (240 liquid tons) of sewage sludge in 1980. The Act also requires industries to pretreat their wastewater streams prior to discharge to a receiving stream or to a municipal sewage treatment plant. Industrial wastewater pretreatment will produce a large variety of sludges, depending upon the composition of the wastewater and the treatment technology employed. In the case of air pollution laws, the major impact is the requirement for the gas desulfurization equipment on fossil fueled electric generating plants. This equipment removes sulfur dioxide from a plant's gaseous effluent. The technology for accomplishing SO, removal generates large quantities of sulfur oxide throwaway sludges. Installation of these flue gas desulfurization (FGD) systems on the Nation's power plants may result in the generation of more than 60 million dry tons of these residual wastes annually by 1980. Question 17a. Does disposal of sewage sludge in sanitary landfills constitute a serious problem for groundwater pollution? Answer. At this time, there have been no reported cases of groundwater pollution as a result of sewage sludge disposal in a sanitary landfill. This is not to say that the potential for pollution is not present. The fact that sewage sludge disposal in a sanitary landfill will increase the moisture in the fill would lead one to expect leachate from the fill sooner than a similar fill not accepting sewage sludge. The existence of heavy metals and persistent organics in sludges indicate that serious water pollution could result should leachate containing these constituents reach groundwater. Question 17b. If they are not "hazardous", do air and water residuals otherwise present a significant environmental or health problem? Answer. At present, we think the hazardous portion of the air water residuals will amount to about ten percent of the total waste load and, as such, would fall within the purview of the proposed "Hazardous Waste Management Act." The remaining 90 percent will present a significant environmental problem by virtue of sheer volume. A recent study by Ralph Stone and Company asserts that in 1985, over % of all solid waste (excluding mining waste) will be from air and water residuals, or about four times the amount generated by the same waste streams in 1971. Also, we can assume these wastes will present the same kind of land disposal problems as we have described for municipal solid waste. If disposed in landfills, these sludges will leach because of their high moisture content. Heavy metals and chemicals from the sludges probably will be concentrated in the leachate in hazardous quantities, and the leachate will require both containment and treatment at the site. Question 18. What percentages of waste steel, glass, ferrous metals, and aluminum and paper in post-consumer wastes are now recovered? What are the maximum practicable rates of recovery that have been estimated by industry, EPA, or others? Answer. Appropriate post-consumer recycling rates, i.e., the ratio of post-consumer recovery to post-consumer discards from municipal solid waste, are as follows for 1972: Maximum practical recovery levels can only be estimated, based on numerous assumptions relative to technology developments, markets, etc. Going to the upper end of practical recovery maximums for post-consumer recovery would suggest recovery levels of 50 percent for metals and glass and 35 percent for paper. ENVIRONMENT GENCY S PROTECTION UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 10 1974 Honorable Jennings Randolph rited States Senate Washington, 1.C. 20512 bear Senator Randolph. The Pesource Recovery ivision of the huvironmental The study presents some estimates of energy conservation potential that could result from source reduction, energy recovery. recycling and improved collection. It also presents an overview of energy recovery methods and a survey of energy recovery activity throughout the country. The consideration of energy conservation and energy recovery legislation makes this report particularly timely. I hope you find it to be useful during your deliberations. |