Closing the nutrient loop between urban and rural areas: a case study analyzing the technical potential of recycling fertilizers from urban biorefineries

Marielle Trenkner; Andreas Kiesel; Andrea Bauerle; Christiane Chaumette; Valentin Schlecht; Johannes Kurz; Philipp Zeitner; Iris Lewandowski

doi:10.1002/bbb.2801

journal article Open Access Jun 09, 2025

Closing the nutrient loop between urban and rural areas: a case study analyzing the technical potential of recycling fertilizers from urban biorefineries

Marielle Trenkner

Andreas Kiesel

Andrea Bauerle

Christiane Chaumette Valentin Schlecht

Johannes Kurz Philipp Zeitner Iris Lewandowski

Biofuels, Bioproducts and Biorefining Vol. 19 No. 6 pp. 2025-2046 · Wiley

View at Publisher Save 10.1002/bbb.2801

Abstract

Abstract
The world’s population is expected to grow rapidly, with the vast majority of people living in urban areas. Closing nutrient loops is therefore increasingly important for food security and environmental stability. In Germany however, the current treatment of organic and green waste and sewage sludge (derived from wastewater) includes composting and co‐incineration, resulting in significant nutrient losses. This paper analyses the technical potential of novel urban biorefinery concepts for the recycling of plant nutrition minerals from waste streams and waste water in metropolitan regions. Using the Stuttgart region as a case study, four modular biorefinery concepts were assessed, including phosphorus precipitation, membrane gas absorption, and insect‐based bioconversion. These technologies produce valuable recycling fertilizers – such as ammonium sulfate, struvite, and organic NPK fertilizers – which meet legal requirements but differ in nutrient concentrations and availability to plants. The implementation of the evaluated biorefinery technologies has the potential to replace almost all conventional fertilizers used in the Stuttgart region with regionally produced recycling fertilizers, while mitigating environmental impacts and creating economic opportunities within a circular bioeconomy. In order to realize this potential, it is necessary to treat not only organic and green waste, but all urban wastewater streams in urban biorefineries. Finally, an urban biorefinery concept is proposed that optimally matches waste streams and specific biorefinery technologies, enabling nutrient recovery from organic waste and wastewater and supporting the development of regionally adapted circular strategies.

Topics

No keywords indexed for this article. Browse by subject →

References

87

[1]

Earth beyond six of nine planetary boundaries

Katherine Richardson, Will Steffen, Wolfgang Lucht et al.

Science Advances 10.1126/sciadv.adh2458

[2]

10.1038/nature01014

[3]

10.4337/9781788972727.00037

[4]

Planetary boundaries: Guiding human development on a changing planet

Will Steffen, Katherine Richardson, Johan Rockström et al.

Science 10.1126/science.1259855

[5]

10.3390/min11101137

[6]

From waste to resource: A systems dynamics and stakeholder analysis of phosphorus recycling from municipal wastewater in Europe

Claudiu-Eduard Nedelciu, Kristín Vala Ragnarsdottír, Ingrid Stjernquist

AMBIO: A Journal of the Human Environment 10.1007/s13280-018-1097-9

[7]

Fertilizer Effect of Phosphorus Recycling Products

Wilhelm Römer, Bernd Steingrobe

Sustainability 10.3390/su10041166

[8]

10.1038/s43016-023-00890-y

[9]

10.1007/s10230‐008‐0058‐0

[10]

10.1016/j.gloenvcha.2012.10.013

[11]

AbfKlärV. AbfKlärV [Internet]. BGBl. I S. 3465 2129–6–6 Sep 27 2017Available at:https://www.gesetze‐im‐internet.de/abfkl_rv_2017/AbfKl%C3%A4rV.pdf.

[12]

10.1016/j.jclepro.2015.05.130

[13]

10.1038/s43016-022-00659-9

[14]

10.2499/9780896294394_22

[15]

Prospects Group, Worldbank (2022)

[16]

IFA (2014)

[17]

10.1038/s41598‐022‐18773‐w

[18]

United Nations (2019)

[19]

10.1016/j.cacint.2023.100104

[20]

10.1016/j.proenv.2016.07.001

[21]

10.1016/s1164-5563(03)00026-8

[22]

10.1016/j.jclepro.2021.130130

[23]

Statistisches Bundesamt (2023)

[24]

Phosphorus speciation in sewage sludge and their ashes after incineration as a function of treatment processes

Charlotte Nilsson, Stefan Karlsson, Bert Allard et al.

Waste Management & Research: The Journal for a... 10.1177/0734242x241252913

[25]

10.1016/j.ecoleng.2015.04.033

[26]

10.1016/j.scitotenv.2016.07.019

[27]

10.1016/j.jclepro.2020.123015

[28]

10.1016/j.chemosphere.2021.130097

[29]

A state-of-the-art review of biowaste biorefinery

Aristotle T. Ubando, Aaron Jules R. Del Rosario, Wei-Hsin Chen et al.

Environmental Pollution 10.1016/j.envpol.2020.116149

[30]

10.1016/j.resconrec.2021.105693

[31]

10.1016/j.resconrec.2020.105218

[32]

10.1016/j.biortech.2019.122673

[33]

10.1016/j.cosust.2020.09.007

[34]

CrosserN Top 10 Most Impactful Bioproducts [Internet]. Ecotech Substack; 2023 Dez [cited February 5th 2024]. (Fifth Industrial)(2023). Available at:https://ecotech.substack.com/p/top‐10‐most‐impactful‐bioproducts.

[35]

Ministry of the Environment BW Nachhaltige Bioökonomie – EFRE‐Förderprogramm “Bioökonomie Bio‐Ab‐Cycling”: Fünf modulare Bioraffinerien erhalten Fördermittel der EU und des Landes [Internet](2022) [cited May 18th 2024]. Available at:https://um.baden‐wuerttemberg.de/de/presse‐service/presse/pressemitteilung/pid/efre‐foerderprogramm‐biooekonomie‐bio‐ab‐cycling‐fuenf‐modulare‐bioraffinerien‐erhalten‐foerdermittel.

[36]

10.9734/ijpss/2019/v31i230208

[37]

10.3390/soilsystems7040100

[38]

10.1016/j.scienta.2021.110855

[39]

Imane L "Fit‐gap analysis: pre‐fit‐gap analysis recommendations and decision support model" Int J Adv Comput Sci Appl (2022)

[40]

Sponagel C "Development of supply curves for biodiversity offsets on agricultural land – a case study from the Stuttgart region" Ger J Agric Econ (2021)

[41]

Landeshauptstadt Stuttgart (2024)

[42]

FAO (via WorldBank) Fertilizer consumption (kilograms per hectare of arable land) [Internet](2023) [cited February 1st 2024]. Available at:https://ourworldindata.org/grapher/fertilizer‐use‐in‐kg‐per‐hectare‐of‐arable‐land?tab=chart&country=~DEU.

[43]

Stadtentwässerung Stuttgart Kennzahlen Hauptklärwerk Mühlhausen [Internet](2020) [cited August 16th 2024]. Available at:https://www.stuttgart‐stadtentwaesserung.de/wp‐content/uploads/2020/09/2019_Kennzahlen‐Hauptkla%CC%88rwerk‐Mu%CC%88hlhausen.pdf.

[44]

Fraunhofer IGB Data on Waste Streams (Sewage Sludge Organic and Green Waste) from the City of Stuttgart(2023).

[45]

10.1016/j.cogsc.2023.100864

[46]

10.1016/j.apenergy.2020.114616

[47]

10.1016/j.seppur.2017.02.031

[48]

BuchnerGA StepputatKJ ZimmermannAWandSchomäckerR Specifying Technology Readiness Levels (TRL) for the Chemical Industry(2019).

[49]

10.1371/journal.pone.0234544

[50]

10.1088/1757-899x/971/5/052050

Showing 50 of 87 references

Metrics

1

Citations

87

References

Details

Published: Jun 09, 2025
Vol/Issue: 19(6)
Pages: 2025-2046
License: View

Authors

M

Marielle Trenkner

Biobased Resources in the Bioeconomy (340b), Institute of Crop Science University of Hohenheim Stuttgart Germany

A

Andreas Kiesel

Biobased Resources in the Bioeconomy (340b), Institute of Crop Science University of Hohenheim Stuttgart Germany

A

Andrea Bauerle

Biobased Resources in the Bioeconomy (340b), Institute of Crop Science University of Hohenheim Stuttgart Germany

C

Christiane Chaumette

Water and Wastewater Treatment Fraunhofer‐Institut für Grenzflächen‐ und Bioverfahrenstechnik IGB Stuttgart Germany

V

Valentin Schlecht

Biobased Resources in the Bioeconomy (340b), Institute of Crop Science University of Hohenheim Stuttgart Germany

J

Johannes Kurz

Biorefineries Initiative Umwelttechnik BW GmbH Stuttgart Germany

P

Philipp Zeitner

Water and Wastewater Treatment Fraunhofer‐Institut für Grenzflächen‐ und Bioverfahrenstechnik IGB Stuttgart Germany

I

Iris Lewandowski

Biobased Resources in the Bioeconomy (340b), Institute of Crop Science University of Hohenheim Stuttgart Germany

Cite This Article

Marielle Trenkner, Andreas Kiesel, Andrea Bauerle, et al. (2025). Closing the nutrient loop between urban and rural areas: a case study analyzing the technical potential of recycling fertilizers from urban biorefineries. Biofuels, Bioproducts and Biorefining, 19(6), 2025-2046. https://doi.org/10.1002/bbb.2801

Closing the nutrient loop between urban and rural areas: a case study analyzing the technical potential of recycling fertilizers from urban biorefineries

You May Also Like