Correction to the method of Talmadge and Fitch

The method of Talmadge and Fitch used for calculating thickener areas was published in 1955. Although in the United States, this method has largely been superseded by the solids flux method, there are other parts in the world that use this method even up to the present. The method, however, is erroneous and this needs to be known to potential users. The error lies in the assumption that the underflow concentration, Cu, and the time of thickening, tu, in a continuous-flow thickener can be obtained from data obtained in a single batch settling test. This paper will show that this assumption is incorrect. (author)