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Research article - Peer-reviewed, 2014

Phosphorus in soil treatment systems: Accumulation and mobility

Eveborn, David; Gustafsson, Jon-Petter; Gustafsson, Jon Petter; Elmefors, Elin; Yu, Lin; Eriksson, Ann Kristin; Ljung, Emelie; Renman, Gunno


Septic tanks with subsequent soil treatment systems (STS) are a common treatment technique for domestic wastewater in rural areas. Phosphorus (P) leakage from such systems may pose a risk to water quality (especially if they are located relatively close to surface waters). In this study, six STS in Sweden (11-28 years old) were examined. Samples taken from the unsaturated subsoil beneath the distribution pipes were investigated by means of batch and column experiments, and accumulated phosphorus were characterized through X-ray absorption near edge structure ()CANES) analysis. At all sites the wastewater had clearly influenced the soil. This was observed through decreased pH, increased amounts of oxalate extractable metals and at some sites altered P sorption properties. The amount of accumulated P in the STS were found to be between 0.32 and 0.87 kg m(-3), which in most cases was just a fraction of the estimated P load (<30%). Column studies revealed that high P concentrations (up to 6 mg L-1) were leached from the material when deionized water was applied. However, the response to deionized water varied between the sites. As evidenced by XANES analysis, aluminium phosphates or P adsorbed to aluminium (hydr)oxides, as well as organically bound P, were important sinks for P. Generally soils with a high content of oxalate-extractable Al were also less vulnerable to P leakage. (C) 2014 Elsevier Ltd. All rights reserved.


On-site wastewater treatment; Septic system; Phosphorus leakage; Column studies; Removal mechanisms; X-ray absorption spectroscopy

Published in

Water Research
2014, volume: 64, pages: 42-52

Authors' information

Eveborn, David
Royal Institute of Technology (KTH)
Swedish University of Agricultural Sciences, Department of Soil and Environment
Gustafsson, Jon Petter (Gustafsson, Jon-Petter)
Royal Institute of Technology (KTH)
Elmefors, Elin
Swedish Institute of Agricultural and Environmental Engineering (JTI)
Yu, Lin
Lund University
Eriksson, Ann Kristin
Swedish University of Agricultural Sciences, Department of Soil and Environment
Ljung, Emelie
Swedish Institute of Agricultural and Environmental Engineering (JTI)
Renman, Gunno
Royal Institute of Technology (KTH)

UKÄ Subject classification

Other Environmental Engineering
Environmental Sciences

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