Blackwater treatment and fate of pharmaceuticals and antibiotic resistance genes

Last changed: 17 January 2024
Sources of pharmaceuticals and antibiotic resistant genes such as medicines and household chemicals, the blackwater cleaning and a question mark indicating a possible risk for plants and recipients. Illustration.

This Formas project provided knowledge about the benefits and potential environmental risks associated with blackwater treatment and use as fertiliser in agriculture.

Treatment and the use of blackwater (faeces, urine, toilet flushing water) in agriculture has many benefits, such as the recovery of a nutrient-rich agricultural product and closing the nutrient cycle, and thereby reducing the need for artificial fertilisers. Nevertheless, blackwater may contain several pathogens, high levels of pharmaceuticals, active metabolites, as well as bacteria carrying antibiotic-resistant genes (ARGs).

Therefore, before using blackwater, appropriate treatment and sanitation (neutralising the pathogens) is needed to avoid the spread of harmful pollutants in the environment.

To use black water safely, this project evaluated state-of-the-art treatment techniques for black water. A particular focus was on pharmaceutical residues and antibiotic-resistant genes to determine if technological improvements are needed. The project carried out experiments and field studies at sites where blackwater, manure and sludge have been spread. A theoretical risk assessment was carried out to investigate whether black water reuse is a significant vector for the spread of these contaminants in the environment and to compare with environmental risks associated with traditional agricultural practices.

The results from the project are published: 

Lai, F.Y., Muziasari, W., Virta, M., Wiberg, K., Ahrens, L. (2021). Profiles of environmental antibiotic resistomes in the urban aquatic recipients of Sweden using high-throughput quantitative PCR analysis. Environmental Pollution, 287, 117651.

Gros, M., Ahrens, L., Levén, L., Koch, A., Dalahmeh, S., Ljung, E., Lundin, G., Jönsson, H., Eveborn, D., Wiberg, K. (2020). Pharmaceuticals in source separated sanitation systems: Fecal sludge and blackwater treatment. Science of The Total Environment, 703, 135530.



SLU: Foon Yin Lai, Lutz Ahrens, Karin Wiberg
ICRA, Girona, Spain: Meritxell Gros


Funding: Formas.