Removal of potentially toxic metals from sewage sludge using EDTA


  • Anela KAURIN Univerza v Ljubljani, Biotehniška fakulteta, Oddelek za agronomijo, Slovenija
  • Juan Francisco MORALES ARTEAGA Univerza v Ljubljani, Biotehniška fakulteta, Oddelek za agronomijo, Slovenija
  • Domen LEŠTAN Univerza v Ljubljani, Biotehniška fakulteta, Oddelek za agronomijo ENVIT, okoljske tehnologije in inženiring, Slovenija



EDTA, toxic metals, remediation, sewage sludge, wastewater treatment plants, aerobic biological treatment, anaerobic biological treatmen


Sewage sludge has the potential to be used as a fertilizer in agriculture because of its high nutritional value, but it is often contaminated with toxic metals (TM). This study investigated whether ReSoil® technology, based on the use of EDTA (50, 70, and 100 mmol l-1), efficiently removes TM from sewage sludge collected after aerobic (blato1) and anaerobic (blato2) treatment. The highest removal efficiency of Pb was achieved in blato1 (up to 60 %) and of Zn and Cu in blato2 (up to 55 and 29 %, respectively). The content of nutrients did not change significantly after remediation, only available phosphorus decreased up to 1.7-times in blato2, but its content remained high (489-510 mg 100-1 g-1). After remediation, the concentration of all metals, except Zn, in the leachates was below the limit for non-hazardous substances. To demonstrate the possibility of recycling process solutions and EDTA, blato2 was washed in 5 consecutive batches with 50 mmol l-1 washing solution, removing on average 28 % Pb, 48 % Zn, 35 % Cu, 30 % Mn, and 10 % Fe. ReSoil® technology removes metals from sludge and preserves its nutritional value. However, the efficiency of the technology depends on the treatment process used in the wastewater treatment plant.

Author Biographies

  • Anela KAURIN, Univerza v Ljubljani, Biotehniška fakulteta, Oddelek za agronomijo, Slovenija
    Oddelek za agronomijo
  • Juan Francisco MORALES ARTEAGA, Univerza v Ljubljani, Biotehniška fakulteta, Oddelek za agronomijo, Slovenija
    Oddelek za agronomijo
  • Domen LEŠTAN, Univerza v Ljubljani, Biotehniška fakulteta, Oddelek za agronomijo ENVIT, okoljske tehnologije in inženiring, Slovenija
    Oddelek za agronomijo


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30. 12. 2022



Original Scientific Article

How to Cite

KAURIN, A., MORALES ARTEAGA, J. F., & LEŠTAN, D. (2022). Removal of potentially toxic metals from sewage sludge using EDTA. Acta Agriculturae Slovenica, 118(4), 1–14.

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