Laboratory tests for the technological characterization of sewage sludge are catalogued and reviewed. Procedures presently being tested and evaluated by IRSA (Water Research Institute, C.N.R., Italy) are also discussed.
Major attention is addressed to the evaluation of sludge dewaterability, since this operation is both expensive and widely utilized in sludge management. In particular, a new procedure for estimating the full-scale filterpress cake concentration and the floc-strength method for evaluating sludge centrifugability are described. Further studies are, however, required for a better correlation with industrial-scale operations.
Other methodologies concern thickening, stabilization, final treatment and disposal: acceptable and simple tests are generally not available and in many cases it is difficult to interpret the data that are generated.
The discussion gives evidence of the laboratory tests now used for sludge characterization being specific to the method of treatment; tests yielding basic information about sludge are thus needed.
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Heide, B.A., Kampf, R. & Visser, M.A. (1982), Manual for the selection and use of polyelectrolytes in dewatering sludge with beltpresses, TNO Report A 124E. Delft, The Netherlands.
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Mininni, G., Santori, M. & Spinosa, L. (1982), Tecnologie e problemi della disidratazione dei fanghi (Technologies and problems of sludge dewatering), L'Agricoltura Italiana, 119, 130-146.
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20.
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21.
Spinosa, L., Mininni, G., Barile, G. & Lore', F. (1984), Study of belt-press operation for sludge dewatering . In Proceedings of the Conference Solids/Liquids Separation practice and the Influence of New Techniques, Leeds, U.K., 3-6 April 1984, pp. 85-96.
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