Land application of sewage sludge seems justifiable mostly because of its phosphorus content. Depending on the distribution of cattle manure the total Danish supply of phosphorus could be provided by manure and sludge. Or sludge phosphorus could substitute from 30—100% of all imported raw phosphates utilized domestically for agricultural purposes.
Increased sludge phosphorus production would require extended waste water treatment. Due to increased costs of imported phosphorus such treatment may actually prove economically sound using well known technology. Furthermore it may reduce eutrofication of receiving waters.
Recent research shows that Danish sludge need not contribute more Cadmium to soil than chemical fertilizers, if both are applied only accordingly to plant phosphorus demand. Consequently, increased sewage sludge application in agriculture should be deemed favourable compared with present extensive use of chemical fertilizers.
Arvin, E. & Nielsen, M.K. (1983), Fosforfjernelse i rensningsanlæg (Phosphorus removal in sewage treatment plant), Stads- og Havneingeniøren, 5, 130-136,
2.
Aslyng, H.C. (1964), Phosphate potential and phosphate status of soils , Acta Agriculturœ Scandinavica, 14, 261-285.
3.
Catroux, G., Chassod, R., Gupta, S., Haan, S. de, Hall, J., Suess, A. & Williams, J.H. (1982), Nitrogen and Phosphorus Value of Sewage Sludges. Concerted Action. Report of a CEC working group (Cost project 68 Ter, group 4, Agricultural value of sludge).
4.
Cervenka, L. von & Timmermann, F. (1976), Phosphatfällungsprodukte aus biologisch geklärten Siedlungsabwässern und ihre Verwendungsmöglichkeit in der Landwirtschaft (Precipitates from phosphorus removal in biological waste water treatment plants and their use in agriculture), Landwirtschaftlische Forschung, 29, 299-308.
5.
Chang, A.C., Page, A.L., Sutherland, F.H. & Grgurevic, E. (1983), Fractionation of phosphorus in sludge-affected soils, Journal of Environmental Quality, 12, 286-290.
6.
Geering, J. (1965), Über den landwirtschaftlischen Nutzwert von AbfaHstoffen nach Ergebnissen von Gefässe- und Feldversuchen (Pot and field studies of the agricultural value of recycled waste), Schweizerische landwirtschaftliche Forschung, 3, 277-317.
7.
Gestring, W.D. & Jarrell, W.M. (1982), Plant availability of phosphorus and heavy metals in soils amended with chemically treated sewage sludge, Journal of Environmental Quality, 11, 699—675.
8.
Haan, S. de (1981), Sewage sludge as a phosphate fertilizer. Proceedings of the E.E.C. Seminar Phosphorus in Sewage Sludge and Animal Wastes, Groningen, The Netherlands, 12-13 June 1980, pp. 149-162. D. Reidel, Dordrecht, The Netherlands.
9.
Häni, H., Gupta, S.K. & Furrer, O.J. (1981), Availability of phosphorus fractions in sewage sludge. Proceedings of the E.E.C. Seminar Phosphorus in Sewage Sludge and Animal Wastes, Groningen, The Netherlands, 12-13 June 1980, pp. 177-189. D. Reidel, Dordrecht, The Netherlands.
10.
Hansen, J. & Tjell, J. Chr. (1981), Slammets jordbrugsanvendelse. Overblik (Land application of sewage sludge, an overview). Polyteknisk Forlag, Lyngby, Denmark.
11.
Koskela, I. (1981), Phosphorus in sewage sludge in Finland. Proceedings of the E.E.C. Seminar Phosphorus in Sewage Sludge and Animal Wastes, Groningen, The Netherlands, 12-13 June 1980, pp. 109-118. D. Reidel, Dordrecht, The Netherlands.
12.
Kuile, M., White, R.E.& Beckett, P. H. T, (1983), The availability to plants of phosphate in sludges precipitated from the effluent from sewage treatment, Water Pollution Control, 82, 582-589.
13.
Larsen, K. (1981), Phosphorus effect of animal manure and sewage sludge. Proceedings of the E.E. C. Seminar Phosphorus in Sewage Sludge and Animal Wastes, Groningen, The Netherlands, 12-13 June 1980, pp. 207-229. D. Reidel, Dordrecht, The Netherlands.
Norsk Hydro A/S (1984), Prices and consumption of phosphorus in fertilizers. Personal communication from P. Marcussen, Norsk Hydro A/S, Copenhagen, Denmark.
16.
Pauly, H. & Simonsen, A. (1973), 22 Danish Sewage Plants Sludge Analysed for 29 Elements. Mineralogical Institute, Technical University of Denmark, Lyngby, Denmark.
17.
Petterson, O. & Ericsson, J. (1979), Tungmetaller och avloppsslam i jordbruket (Heavy metals and sewage sludge in agriculture). Aktuelt från Lantbruksuniversitetet , 274, Uppsala , Sweden.
18.
Pommel, B. (1981), Phosphorus value of sludges related to their metal content. Proceedings of the E.E.C. Seminar Phosphorus in Sewage Sludge and Animal Wastes, Groningen, The Netherlands, 12-13 June 1980, pp. 137-148. D. Reidel, Dordrecht, The Netherlands.
19.
Skov, T. (1982), Koncentrationen af metaller i spildevandsslam er på vej ned (Heavy metals in sludge show downward trend), Stads- og Havneingeniøren, 12, 375-380.
20.
Sommers, L.E. (1977), Chemical composition of sewage sludges and analysis of their potential use as fertilizers, Journal of Environmental Quality, 6, 225-232.
21.
Soon, Y.K. & Bates, T.E. (1982), Extractability and Solubility of phosphate in soils amended with chemically treated sewage sludges, Soil Science, 134, 89-96.
22.
Superfos (1979), Cadmium i handelsgødninger på det danske marked (Cadmium in Danish chemical fertilizers). Personal communication from P. Eichner , Superfos, Vedbæk, Denmark.
23.
Timmerman, F., Cervenka, L. & Baran, E. (1981), Phosphatverfügbarkeit von Klärschlämmen aus der dritten Reinigungsstufe. I: Characterization, Treatment, and Use of Sewage Sludge. Proceedings of the Second European Symposium , Vienna, 21-23 October 1980, pp. 511-520. D. Reidel, London, U.K.
24.
U.S. Epa (1978), Cadmium Additions to Agricultural Lands Via Commercial Phosphatic Fertilizers, EPA Report SW-718. U.S. Environmental Protection Agency, Washington, D.C., U.S.A.
