Carbon footprint of urban source separation for nutrient recovery

H Kjerstadius; A Bernstad Saraiva; J Spångberg; Å Davidsson

doi:10.1016/j.jenvman.2017.03.094

Carbon footprint of urban source separation for nutrient recovery

J Environ Manage. 2017 Jul 15:197:250-257. doi: 10.1016/j.jenvman.2017.03.094. Epub 2017 Apr 6.

Authors

H Kjerstadius¹, A Bernstad Saraiva², J Spångberg³, Å Davidsson⁴

Affiliations

¹ Water and Environmental Engineering, Department of Chemical Engineering, Lund University, P.O. Box 124, 221 00 Lund, Sweden. Electronic address: hamse.kjerstadius@chemeng.lth.se.
² SAGE/COPPE, UFRJ, Rio de Janeiro, Brazil; SAGE/COPPE, UFRJ, Centro de Gestão Tecnológica - CT2, Rua Moniz de Aragão, no. 360 - Bloco 2, Ilha do Fundão - Cidade. Universitária, Rio de Janeiro, RJ 21.941-972, Brazil.
³ Swedish University of Agricultural Sciences, Department of Energy and Technology, Box 7032, 750 07 Uppsala, Sweden.
⁴ Water and Environmental Engineering, Department of Chemical Engineering, Lund University, P.O. Box 124, 221 00 Lund, Sweden.

PMID: 28391098
DOI: 10.1016/j.jenvman.2017.03.094

Abstract

Source separation systems for the management of domestic wastewater and food waste has been suggested as more sustainable sanitation systems for urban areas. The present study used an attributional life cycle assessment to investigate the carbon footprint and potential for nutrient recovery of two sanitation systems for a hypothetical urban area in Southern Sweden. The systems represented a typical Swedish conventional system and a possible source separation system with increased nutrient recovery. The assessment included the management chain from household collection, transport, treatment and final return of nutrients to agriculture or disposal of the residuals. The results for carbon footprint and nutrient recovery (phosphorus and nitrogen) concluded that the source separation system could increase nutrient recovery (0.30-0.38 kg P capita^-1 year^-1 and 3.10-3.28 kg N capita^-1 year^-1), while decreasing the carbon footprint (-24 to -58 kg CO₂-eq. capita^-1 year^-1), compared to the conventional system. The nutrient recovery was increased by the use of struvite precipitation and ammonium stripping at the wastewater treatment plant. The carbon footprint decreased, mainly due to the increased biogas production, increased replacement of mineral fertilizer in agriculture and less emissions of nitrous oxide from wastewater treatment. In conclusion, the study showed that source separation systems could potentially be used to increase nutrient recovery from urban areas, while decreasing the climate impact.

Keywords: Carbon footprint; Food waste; Life cycle assessment; Nutrient recovery; Source separation; Wastewater management.

MeSH terms

Carbon Footprint*
Phosphorus
Sweden
Waste Disposal, Fluid*
Wastewater

Substances

Waste Water
Phosphorus