Variable Nature of Chemical Composition of Sewage Sludges1
- L. E. Sommers,
- D. W. Nelson and
- K. J. Yost2
Sewage sludge samples were collected over a 2-year period from eight Indiana cities and analyzed for C, N, P, K, Ca, Mg, Fe, Cd, Zn, Cu, Ni, and Pb. The sludges contained approximately 50% organic matter and 1–4% inorganic C. Organic and inorganic C, organic N, inorganic P, and Ca and Mg were found to be present in a given sludge at a relatively constant concentration with respect to sampling time. Inorganic N, organic P, K, and all metals were found to be quite variable with time for sewage sludge produced by a given city. In general, organic N and inorganic P constituted the majority of total N and P, respectively, in sludges. The largest deviations between the mean and median were found for Cd, Zn, Cu, Ni, and Pb. Variable nature of inorganic N and metal contents of sludges indicates that a sound sampling and analysis program is essential prior to formulating recommendations for rates of sewage sludge applications on soils used for crop production.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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