Estimation of the effective area of filtration for the determination of the specific resistance to filtration of sewage sludge

The specific resistance to filtration of a sewage sludge is a quantitative measure of the intrinsic filtration properties of a sewage sludge. A measure of this parameter is of considerable value if the dewatering of the sewage sludge is to be undertaken. Determination is normally undertaken on a filter paper supported by a Buchner funnel. There exists some uncertainty as to the effective area of filtration. In some studies the entire area appeared effective, whilst in others the peripheral area was only partially effective. In this study the area available for filtration was reduced by the use of waxed paper rings of various sizes. It was evident that the entire area of the filter bed was not effective in filtration.