The objective of this study was to compare the effects of different dewatering processes on the phosphorus (P) availability of an FeCl3‐precipitated and lime‐conditioned sludge having an initial dry matter content (DMC) of 4%. The sludge was dewatered by either drying (D), freezing/thawing (FT) or centrifugation (C) until a DMC of about 15% was reached. Thereafter the FT and D sludges were gently dried to obtain a DMC increasing up to 50 to 60%. The plant‐available sludge P was assessed by the change in the isotopic dilution of P taken up by ryegrass (Lolium perenne[L]) after sludge amendments to one soil. After the plant experiment, the soil‐to‐solution transfer of P ions and bicarbonate‐and ammonium lactate‐extractable P were determined in selected soil samples. The amount of plant‐available P (L‐value) and the contribution of sludge P to plant nutrition (%Pdfsl) in soil amended with non‐dewatered sludge (ND) were not significantly different from the L and percentage Pdfsl values of soils amended with FT, D and C sludges. Nor did the subsequent drying of D and FT sludges significantly change the L and percentage Pdfsl values. Hence, the dewatering processes did not significantly alter the initial sludge P availability. The soil‐to‐solution transfer of P ions and the chemically extracted P did not significantly differ between the different sludge‐amended soil samples. The percentage Pdfsl values can be predicted by percentage ΔE1, since the overall average relative increase (%ΔE1) in the immediate soil‐to‐solution transfer of P ions did not significantly differ from the percentage Pdfsl values.

We explore an idea of transferring some classic measures of global dependence between random variables , , ,

No abstract

The objective of this study was to compare the effects of different dewatering processes on the phosphorus (P) availability of an FeCl3-precipitated and lime-conditioned sludge having an initial dry matter content (DMC) of 4%. The sludge was dewatered by either drying (D), freezing/ thawing (FT) or centrifugation (C) until a DMC of about 15% was reached. Thereafter the FT and D sludges were gently dried to obtain a DMC increasing up to 50 to 60%. The plant-available sludge P was assessed by the change in the isotopic dilution of P taken up by ryegrass (Lolium perenne [L]) after sludge amendments to one soil. After the plant experiment, the soil-to-solution transfer of P ions and bicarbonate-and ammonium lactate-extractable P were determined in selected soil samples. The amount of plant-available P (L-value) and the contribution of sludge P to plant nutrition (% Pdfsl) in soil amended with non-dewatered sludge (ND) were not significantly different from the L and percentage Pdfsl values of soils amended with FT, D and C sludges. Nor did the subsequent drying of D and FT sludges significantly change the L and percentage Pdfsl values. Hence, the dewatering processes did not significantly alter the initial sludge P availability. The soil-to-solution transfer of P ions and the chemically extracted P did not significantly differ between the different sludge-amended soil samples. The percentage Pdfsl values can be predicted by percentage Δ E1, since the overall average relative increase (%Δ E1) in the immediate soil-to-solution transfer of P ions did not significantly differ from the percentage Pdfsl values.

No abstract