The mean daily air temperatures are used to calculate the AT value. The calculations take account of thaw periods, and a new sludge application is not made until the previous layer has frozen completely. One day is then allowed for a new sludge application and cooling, and calculations with Equation 9.3 are repeated to again determine the freezing time. The procedure is repeated through the end of the winter season. A tabular summary is recommended for the data and calculation results. This procedure can be easily programmed for rapid calculations with a spreadsheet or desktop calculator.
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