LANDFILLS, THE 1977 FATE OF AIR AND WATERBORNE WASTES
Authors: Williams Roy E. 
Published: July 2006

This paper is designed to provide technical data supporting the concepts presented in the guest editorial of William H. Walker, Chairman, NWWA Technical Division, as presented in Ground Water, Vol. 12, No. 5, September‐October 1974. The guest editorial was entitled, “Our Buried Resource, May It Rest in Peace.”

The Federal Water Pollution Control Act Amendment of 1972 (Public Law 92‐500) will necessitate a significant expansion of landfill facilities and operations throughout the United States by 1977. The nature of the additional materials to be introduced into landfills as a consequence of this law will require additional precautionary measures if pollution of ground water by lixiviation is to be precluded. Recent studies of the waste production characteristics of the aluminum industry contain documentary evidence for this conclusion. The aluminum industry is representative of conditions in the iron and steel industry, the ferroalloy industry, and the copper, lead and zinc industries (see Williams, 1975). Mr. Walker discussed only the fossil fuel power production industry.

Public Law 92‐500 specifies July 1, 1977, as the deadline date for application of the “Best Control Technology Currently Available” to point source waste water discharges from essentially all U.S. industries. In many cases these industries convert airborne wastes to waterborne wastes by utilization of wet or semi‐wet air pollution control techniques. In the majority of these cases the best control technology currently available consists of converting these waterborne wastes to solid wastes by some combination of pH control, precipitation and coagulation. Where recycle is impossible, these solid wastes must be discarded in sanitary landfills or similar solid waste disposal sites.

In primary aluminum plants wherein dry fume scrubbing is not employed, effluents from wet scrubbers used for air pollution control constitute the major waste water. The major contaminants in this water are soluble fluorides, suspended solids and organic constituents. These wastes (initially airborne) result from the production of fluoride compounds during the electrolytic process and the consumption of coke and petroleum products as anode materials. Fluoride content ranges from 10 to 30 mg/l in various waste streams. Bleed streams from wet scrubbers must be neutralized for precipitation of fluoride as calcium fluoride or sodium aluminate can be added to precipitate fluoride as cryolite. Complete recycle of scrubber effluent is precluded by sulfate buildup. The precipitated fluoride compounds are contaminated by other compounds and frequently are too impure for recycle; thus they must be landfilled. Because many of these compounds are subject to lixiviation under acid conditions extreme care will be required if pollution of ground water is to be precluded. A similar situation exists in the secondary aluminum recovery industry.

The primary and secondary aluminum recovery industries constitute examples of industries wherein compliance with Public Law 92‐500 should include preparation and planning for additional landfill sites if ground‐water pollution is to be precluded.