Summary
Thiobacillus thiooxidans is capable of oxidizing sulfur in digested sludge, while decreasing the pH value from about 5.5 to, say, 1.0 to 1.5. Insoluble metal sulfides can be solubilized through this acidification. Thiobacillus ferrooxidans oxidises pyritic ore in the presence of 6% centrifuged sludge if the pH value is adjusted to about 2.5. When mixing T. thiooxidans and T. ferrooxidans with sludge and 1% sulfur, the former acidifies the sludge and the latter oxidizes metal sulfides; together they solubilize more metal than T. thiooxidans alone. The following metals solubilized from their sulfides have been investigated so far: iron, copper, zinc, nickel, and cadmium. The possibility of recycling metals from sewage sludge with this method is discussed.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Eggersdorfer, R., Müller, U., Oberbacher, B., Schönborn, W. (1973). Abwassertechn. 5, I-III and 6, V-III
Gaul, D., Scholl, W., Strauch, D., Müller, W., Miersch, K. (1975). Kompost aus Klärschlamm. In: Hohenheimer Arbeiten, G. Alleweldt, ed., 78, pp 1–75 Stuttgart: Eugen Ulmer
Mosey, F.E., Swanwick, J.D., Hughes, D.A. (1971). Water Pollut. Control 70, 668–680
Pings, W.B. (1968). Colorado School of Mines, Mineral Ind. Bull. Vol. II 3, 1–19
Schönborn, W., Hartmann, H. Gas-Wasserfach (in preparation)
Schwartz, W. (1972). Mineral Deposita (Berl.) 7, 25–30
Silverman, M.P., Ehrlich, H.L. (1964). Adv. appl. Microbiol. 6, (1964) 153–206
Torma, A.E., Tabi, M. (1973). L'Ingénieur 59, 2–8
Tuovinen, O.H., Kelly, D.P. (1972). Zschr. Allg. Mikrobiol. 12, 311–346