Factors influencing the recovery of organic nitrogen from fresh human urine dosed with organic/inorganic acids and concentrated by evaporation in ambient conditions

Published

Can we evaporate water from acidified fresh human urine to produce a solid fertiliser? Yes, we can! In our latest article in Science of the Total Environment (STOTEN), my colleagues (Anastasija Vasiljev, Dyllon Randall and Bjorn Vinneras) and I show how human urine can be treated to produce fertilisers with nutrient content similar to that of blended synthetic/mineral fertilisers sold on the market. In fact, we can produce a fully #biobased #urine #fertiliser containing more than 20% nitrogen by dosing fresh urine with organic acids and dehydrating it in ambient conditions. So dig into our article if you’re as fascinated by #urinechemistry as we are, because we also attempt to understand the factors that affect the recovery of nitrogen-containing organic compounds in urine.

Producing fertilisers from urine-derived nutrients is highly relevant in today’s context, where globally the increase in fertiliser prices is affecting food production and causing more global hunger. On the other hand, segregating urine at source and safely #recycling it also one “beyond the business as usual” approach to achieving the sustainable development goal on water and sanitation #SDG6, a goal whose targets we are in serious risk of not meeting by 2030.

We therefore hope to transfer results from our paper to exciting projects such as P2GreeN and REWAISE EU project where urine recycling systems are being piloted in real-world settings!

Hybrid PhD course on Safe nutrient recycling and management

Published

We at Kretsloppsteknik are currently giving a hybrid (onsite/online) course on Safe nutrient recycling and management (10 credit) within the
research school Sustainable systems for food, energy and biomaterials (SSFEB). The aim of the course is to give the student knowledge in current waste and wastewater management techniques, with focus on technologies for plant nutrient recovery and reuse. Today, 75% of all biodegradable solid waste is landfilled or dumped and 90% of all wastewater generated is either not treated or only partially treated. In cases when the waste is treated, treatments are not focused on recycling, but rather removal, of plant nutrients, as they can otherwise risk to pollute the environment. If the plant nutrients in the waste and wastewater were collected they could replace 25-50% of the virgin resources used for production of chemical fertilizers used in agriculture. Looking at waste and wastewater as resources is a paradigm shift, and for this shift to happen new technologies and management systems are required. When closing the loop of nutrients there is a risk of recycling unwanted substances as well, e.g. heavy metals and pathogens. Upon completion of the course the student should know the flow of waste and wastewater in society, possible treatment methods for closing the loop of nutrients and the risks associated with closed loop systems, as well as methods for mitigating circulation of unwanted substances.

 

Picture from our last seminar, with two participants being onsite and four participants joining online from India, China and Rwanda.

Recent study on faecal sludge qualities and quantities and potential for resource recovery in Phnom Penh, Cambodia

Published

At the current progress rate, there will probably still be 2.8 billion people world-wide without safely managed sanitation by 2030. Faecal sludge treatment is crucial for safely managed sanitation. To incentivize and increase implementation of sustainable faecal sludge management (FSM), especially in the cities of low and middle-income countries like Phnom Penh, Cambodia, there should be radial shift in viewing human waste as a resource. However, planning data, e.g. on qualities, quantities and fate of faecal sludge after leaving households are, inadequate and lack of accuracy. This study aimed to provide baseline data for effective FSM planning by sanitation stakeholders in Phnom Penh. This was done by characterizing the physical and chemical properties of faecal sludge in Phnom Penh, identifying sources of variation in faecal sludge composition, quantifying sludge volomes generated, transport logistics and resoruce recovery potential to incentivize sustainable management. In total, 194 faecal sludge samples collected during containment unit emptying were analyzed for physicochemical parameters. Interviews were conducted with users and emptying and transportation contractors, together with collection of technical data about on-site sanitation systems. Geographical coordinates of household sampling locations and disposal sites were also mapped.

The results showed that the concentation of many faecal sludge parameters such as nutrients and organic matter are at the lower end of the range reported for other similar cities worldwide, but still higher than the permissible Cambodian wastewater discharge level. The three predictors influencing faecal sludge characteristics included the addition of water during emptying, connection to the urban drainage network and the type of wastewater captured by household containment system. Cheung Ek and Kob Srov wetlands are the main recipients of faecal sludge collected in Phnom Penh with the amount of 18,800m3 and 13,700m3 annually (Figure 1), respectively. The analysis showed that faecal sludge in Phnom Penh contains valuable resources such as nitrogen (6 tons), phosphorus (13 tons) and energy (148-165 GWh) annually. The baseline data would be useful inputs for decision makers and planners in developing action plan for FSM in Phnom Penh and similar cities.



Read the whole papers:

Eliyan, C., Vinnerås, B., Zurbrügg, C., Koottatep, T., Sothea, K., and McConville, J. (2022). Factors Influencing Physicochemical Characteristics of Faecal Sludge in Phnom Penh, Cambodia. J. Water Sanitation Hyg. Development. 12 (1), 129–140. doi:10.2166/washdev.2021.193

Eliyan C, McConville JR, ZurbrĂĽgg C, Koottatep T, Sothea K and VinnerĂĄs B (2022) Generation and Management of Faecal Sludge Quantities and Potential for Resource Recovery in Phnom Penh, Cambodia. Front. Environ. Sci. 10:869009.
doi: 10.3389/fenvs.2022.869009

Funding from the Kamprad Foundation will help address issues with mineral precipitation in urine collection systems

Published

Håkan Jönsson and Prithvi Simha were very pleased to hear last week that the Kamprad Family Foundation decided to grant them #funding for a two-year project that will address issues with #precipitation of minerals in #sanitation systems that separately collect #urine. Together with Dyllon Randall (an August T Larsson Guest Researcher at Swedish University of Agricultural Sciences (SLU)), they will develop techniques for preventative maintenance/cleaning of toilets. They also plan to develop technologies that capture mineral precipitates at the toilet, thereby preventing their deposits along wastewater pipes. Much of the work in the project will be done in #collaboration with two housing associations in Stockholm, BRF Understenshöjden and BRF Gebers, where urine-separating toilets were installed more than 20 years ago!

Rich Earth Institute/Brightwater Tools visits SLU

Published

 

Kim Nace and Ryan Homeyer of the Rich Earth Institute/Brightwater Tools visited Prithvi at SLU last month during their European tour of organizations that research and implement source-separation and nutrient recovery. They met over lunch and had discussions on a wide range of urine-related topics – how we collect urine, how we treat urine using our technologies (urine dehydration/SLU and freeze concentration/Rich Earth), our spin-off companies (Sanitation360 and Brightwater Tools), and how we operate in different contexts (Sweden versus the US; where regulations, funding and support are all different). But more importantly, the discussions really showed how similar our organisations are. For instance, our motivation with creating the spin-off companies are similar (to channel funding back to our research institutes rather than to make profit). It seems that organisations and people working with urine recycling could achieve more by joining hands and collaborating. So we really look forward to continuing the dialogue with the folks at Rich Earth Institute/Brightwater Tools.

Open position postdoctoral research fellow for studies on hygienisation in fly larvae composting

Published

We are looking for a postdoctoral research fellow for our research in fly larvae composting, with a focus on the hygiene of the process as well as of the larvae and the treatment residue (frass-compost) from the treatment of society’s biodegradable waste. The work will be conducted in close collaboration with researchers and doctoral candidates in the group who work on related issues. The focus is to evaluate the degradation of various biological infectious agents such as bacteria (also spore-forming), bacteriophages and prions. The postdoctoral fellow is expected to pursue the following studies: 1) fate of prions in fly larvae composting; 2) fate of anaerobic spore-forming bacteria in fly larvae composting, and 3) study of mechanisms for killing salmonella in fly larvae composting.

Click here for more information.

Visit from CompoCloset founders to discuss urine treatment

Published

The co-founders of CompoCloset, Erica Pugh and Richard Peter, visited SLU to discuss ways in which source-separated urine can be treated on-site. They have developed a composting toilet, Cuddy, that is specifically designed for vanlife that fits in small places like vans, tiny homes, cabins, and boats. They had nice discussions with Prithvi about ways in which SLU, Sanitation360 and CompoCloset could work together; e.g., by integrating SLU/S360’s urine dehydration technology with the Cuddy toilet.  

The Cuddy toilet. PC: Erica Pugh

Scaling up urine concentration technologies – what are the impacts?

Published

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

Published

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 pĹŤĹŤdcast

Published

Jenna Senecal was interviewed for the Zuloo pĹŤĹŤdcast. 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 pĹŤĹŤdcast 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 –