Environmental impact of sewage sludge ash assessed through leaching

Authors

  • Domagoj Nakić University of Zagreb, Faculty of Civil Engineering http://orcid.org/0000-0003-1747-5451
  • Dražen Vouk Water Research Department, Faculty of Civil Engineering University of Zagreb
  • Shane Donatello Institute for Prospective Technological Studies, Joint Research Centre
  • Aleksandra Anić Vučinić Faculty of Geotechnical Engineering, University of Zagreb

Keywords:

sewage sludge ash (SSA), heavy metals, leaching, landfill, cement mortar

Abstract

As part of a wider feasibility study on the possible reuse potential of Croatian sewage sludge ash, ash has been produced by laboratory incineration of sewage sludge from two Croatian wastewater treatment plants. The Croatian sewage sludge ash was tested for soluble heavy metals according to EN 12457 and results considered in the context of EU landfill Waste Acceptance Criteria. With sewage sludge ash alone, the main soluble elements/ions of concern were (in decreasing order): Mo, SO4, Cr and Cl. When obtained ash was incorporated into cement mortars at cement replacement rates of 20%, EN 12457 leaching of the crushed mortars demonstrated compliance with the strictest limits for inert landfill Waste Acceptance Criteria and well within other limits specified for use in road bases. However, much of the reduction in leaching levels can be attributed to the dilution effect of sand used in mortars. In the cases of Se, Cr, F and Cl, results imply that the cement used in the mortars actually represents a more significant source of soluble Se, Cr, F and Cl than the produced ash. Regardless, the overall results reveal that leaching of heavy metals and other ions is not a significant concern that would prevent the potential reuse of Croatian sewage sludge ash in cement mortars or concretes should Croatian wastewater treatment plants opt for sewage sludge incineration as an alternative sludge disposal and management option.

Author Biography

Domagoj Nakić, University of Zagreb, Faculty of Civil Engineering

Water Research Department, Phd Student, Professional Assistant

Downloads

Published

2017-05-22

Issue

Engineering Review, Vol. 37, No. 2

Section

Articles

License

Engineering review uses the Creative Commons Attribution-NonCommercial-NoDerivatives (CC-BY-NC-ND) 4.0 International License, which governs the use, publishing and distribution of articles by authors, publishers and the wider general public.

The authors are allowed to post a digital file of the published article, or the link to the published article (Enginering Review web page) may be made publicly available on websites or repositories, such as the Author’s personal website, preprint servers, university networks or primary employer’s institutional websites, third party institutional or subject-based repositories, and conference websites that feature presentations by the Author(s) based on the published article, under the condition that the article is posted in its unaltered Engineering Review form, exclusively for non-commercial purposes.

The journal Engineering Review’s publishing procedure is performed in accordance with the publishing ethics statements, defined within the Publishing Ethics Resource Kit. The Ethics statement is available in the document Ethics Policies.