The report describes a procedure for designing an effective monitoring program for fossil-fueled power plant ash pond effluents. Factors that influence effluent characteristics and are important in designing such a monitoring program were determined following a review of plant operating characteristics and ash pond effluent characteristics of TVA's fossil-fueled power plant system. A statistical procedure for determining the sampling frequency of chemical characteristics in ash pond effluents was then developed. Two ways to determine precision are described: Method 1 involves selecting a precision value to estimate the population mean within a given percentage; Method 2 involves calculating a precision value by subtracting an estimate of the population mean from either the ash pond effluent limitation established by EPA or a desirable water quality criterion. Method 2 gives the number of samples required to show that the effluent is in compliance with the effluent limitation or below the water quality criteria. The method chosen to compute the precision depends on the purpose of the monitoring program. The procedure was demonstrated for two TVA ash pond systems.

Prepared for U.S. Environmental Protection Agency, Office of Research and Development, Industrial Environmental Research Laboratory by Tennessee Valley Authority, Office of Power, Division of Energy Demonstrations and Technology. Contract Number: IAG-D5-E-721 November 1979. Bibliography: page 178.