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Release of Phosphorus from Waste-Activated Sludge
- Fine, P., Mingelgrin, U.
- Soil Science Society of America journal 1996 v.60 no.2 pp. 505-511
- sandy soils, calcareous soils, mixtures, phosphorus, organophosphorus compounds, solubility, kinetics, soil solution, nitrogen, nitrification, ammonification, calcium, soil pH, ionic strength, nitrate nitrogen, ammonium nitrogen, inorganic phosphorus, activated sludge
- The dynamics of Prelease from a primarily domestic waste-activated sludge was investigated. More than 70% of the P in the sludge was in mineral form. The inorganic rather than the organic fraction controlled the release of P. Phosphorus release from soil-sludge mixtures into soil solution during 100 d of incubation was measured with and without a corn (L.) crop, in both a calcareous and a noncalcareous sandy soil. The kinetics of inorganic P dissolution from the sludge was also measured in aqueous suspensions during 9 d of incubation. Sludge concentrations were 10 to 100 g kg in the soil-sludge mixtures and 1 and 10 g L in the P-dissolution experiments. The dissolution experiments revealed that up to 40% of the total sludge P dissolved, under the experimental conditions. A continuum of solubilities was displayed by the solid inorganic P components present in the sludge, ranging from that of hydroxyapatite to that of dicalcium phosphate dihydrate. Transformations of N compounds in the sludge-containing systems had strong effects on the dynamics of P dissolution, mainly through the influence of the ammonification and nitrification processes on the pH and the ionic strength and composition of the aqueous solution.