Scaling up urine concentration technologies – what are the impacts?

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There is a growing trend for nutrient recovery from wastewater as part of the transition to a circular economy. Most nutrients in household wastewater originate from urine and one way to facilitate reuse of these nutrients is to concentrate the urine into fertilizer products. Urine concentration technologies are still in the development phase and not implemented at scale. The aim of this study was to provide guidance to technology developers and policymakers by assessing the environmental and societal impacts of urine concentration technologies. In particular, it includes practical aspects such as worker safety, space availability and local fertilizer needs that have not been included in previous studies.

“Although many nutrient recovery technologies are not yet mature, it is good to evaluate them now. First to understand if they contribute to the sustainability that we want to achieve and then to identify improvement opportunities within the technology. It gives us guidance both for technology development and our strategic system planning.” says Jennifer McConville, one of the researchers behind the study.

Future scenarios on implementing three different urine concentration technologies (alkaline dehydration, nitrification-distillation, ion-exchange with struvite precipitation) in a planned residential area in Malmö, Sweden, were developed. The technologies were evaluated using multi-criteria assessment (MCA), with environment, technical, economic and health sustainability criteria derived from the Sustainable Development Goals (SDGs). It was found that all urine concentration technologies performed well against many of the sustainability criteria examined and can contribute to achieving SDGs, especially regarding nitrogen recovery. Specific areas for further development were identified for each technology. In particular:

  • Alkaline urine dehydration requires optimization of energy demand, to reduce the energy consumption and costs.
  • Nitrification-distillation requires optimization of the nitrification rate and matching it to the distillation capacity, which can reduce space requirements and costs. Attention should also be given to risk factors for workers.
  • Ion-exchange with struvite precipitation can be improved with respect to costs and risk for workers, in particular regarding use of sulphuric acid in regeneration of the ion-exchanger.

An impact assessment on scaling up demonstrated that nitrogen emissions to surface water were significantly reduced when more than 60% of urine in Malmö city was subjected to urine concentration. Nitrogen and phosphorus recovered from recycling only 15–30% of urine in Malmö could supply 50% of Malmö municipality’s fertilizer demand.

In the study, the researchers also tested the potential for more large-scale production of fertilizer through a scenario where the technology was scaled up to cover larger parts of Malmö. An up-scaling resulted in significantly lower emissions of nitrogen to the surrounding surface water and if 15 – 30% of the urine in Malmö is collected and concentrated, 50% of the municipality’s need for fertilization can be met.

Read the follow article here:

Gunnarsson, Matilda, Cecilia Lalander, and Jennifer R. McConville. “Estimating environmental and societal impacts from scaling up urine concentration technologies.Journal of Cleaner Production 382 (2023): 135194.

New study on acceptance of human excreta derived fertilizers in Swedish grocery stores

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We have had several studies within the group looking at the acceptability of the use of fertilizers derived from human excreta. Most of them have focused on consumers or farmers. Acceptance among these groups is generally relatively high (or at least not low). Yet, a commonly cited barrier for use of these products is reluctance within the food industry. So we set out to fill this gap by targeting grocery stores in Sweden. The food retail sector, as an intermediary between producers and consumers, is an important actor with power to influence opinions and purchasing practices. In this study, we surveyed 127 food retailers (stores) and reviewed publicly available retailer sustainability policies to assess acceptance of the use of recycled fertilizers. We gauged acceptance of three products relevant for the Swedish market – struvite, phosphorus from ash, and dehydrated urine.




I key take-away from the survey was that food safety is a major concern for these actors. Acceptance of wastewater-derived fertilizers was largely dependent on perceived risks, especially the fate of pharmaceutical residues. Overall, most respondents felt that all three recovery techniques were unlikely to be harmful either to themselves or to the environment. It was more acceptable to use products further away from human consumption. In general, struvite and phosphorus from ash were perceived more positively than dehydrated urine. We speculate that this could be because of the word “urine” in the name or the fact that they are more worried about pharmaceuticals in the urine-derived product. While retailers in Sweden are not negative to reuse, they seem unlikely to provide strong support for nutrient recirculation from human excreta unless it becomes a greater concern for the public. So overall we do not see this sector as key drivers to support a transition to more circular nutrient use, but they are not likely to lobby against it either.

Read the whole paper here:

McConville, Jennifer R., Geneviève S. Metson, and Hugo Persson. “Acceptance of human excreta derived fertilizers in Swedish grocery stores.” City and Environment Interactions 17 (2023): 100096.

Jenna talks about urine on the Zuloo pōōdcast

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Jenna Senecal was interviewed for the Zuloo pōōdcast. While they often talk about the number two, poop, they were eager to learn about how urine can be used as a fertilizer while also limiting our impact on the environment. Welcome to their pōōdcast where they bring insightful news, impact stories and quirky humor to the important topic of sanitation (or lack thereof). Listen to it here or on the youtube clip below –

New JTI-funded project on removing micropollutants from dried urine fertiliser

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SLU has developed an innovative technology that converts human urine to high-quality solid fertiliser. On Gotland, we’ve also shown that urine can effectively fertilise barley, which can be processed further to produce beer. But there is concern about micropollutants that could be present in urine (e.g., pharmaceuticals). Through a three-year project and with funding from Stiftelsen Lantbruksforskning (Swedish farmers’ foundation for agricultural research), we aim to address this concern. First, we will do a baseline study to evaluate fate of micropollutants in the urine chain (fertiliser, barley & beer). Second, techniques will be developed to remove micropollutants so that only plant-essential nutrients are recycled back to farmland. Third, using social science methods and system dynamics modelling, support for recycling urine among food consumers will be assessed. Finally, all the evidence will be presented to stakeholders in the food industry.

Contact: Prithvi Simha

Final Policy Briefs from the SPANS project

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In October 2022, the SPANS project had its final seminar in Kampala, Uganda. The five-year project financed by the Swedish Research Council aimed to improve knowledge related to adaptation and innovation in Sanitation Planning. In particular it explores technical and societal readiness of Alternative Nutrient-recovery Systems. The seminar highlighted the outputs of the project in terms of building knowledge on technologies for resource-recovery, understanding opportunities for implementing such systems and developing a serious game to promote safe resource recovery. All project results can be found on the website: https://www.slu.se/en/departments/energy-technology/projects/kretslopp/spans/

The team also used the seminar to launch the three policy briefs that have been developed in the project:

Abdullah Al-Saadi writing his thesis on fate of urine organics

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My name is Abdullah Al-Saadi. I am originally from Iraq and I live in Finland. In Iraq, I have completed my bachelor degree in Chemical engineering. In Finland, I’m studying a Bachelor degree in Environmental engineering at the final stage. In SLU, I am doing my internship and Bachelor’s thesis project in urine treatment, which will focus on the fate of organic compounds in urine. I will work at SLU for the next 5 months.

Ali Mehaidli to work with fate of nitrogen during urine treatment

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My name is Ali Mehaidli. Prior to my arrival here, I was living in Finland, studying Environmental Engineering at Tampere University of Applied Sciences. At SLU, I will be working with the urine treatment research group. My focus will be on the fate and stability of nitrogen during urine dehydration treatment. My internship and thesis project began in January, and I will be here till early June.

Startup-meeting of the new Horizone Europe project P2Green

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Björn Vinnerås, Jenna Senecal and Jennifer McConville attended the startup-meeting in Hannover during the second week of January. Included in the project from SLU is also Prithvi Simha and two PhD students under employment. Our main work is within the “Swedish pilot region”, where we will focus on the upscaling of the urine dehydration process. Our focus is the first two work packages WP1 – Blue printing the regional clusters and WP2 – Monitoring and assessing the benefits. Jenna was presenting the Swedish pilot region with the full cycle of urine collection to food production. See more at the project home page https://p2green.eu/

Jenna Presenting the Swedish pilot region
Jenna Presenting the Swedish pilot region with the full cycle of fertiliser production from urine to the field and final food production.