Category: English

Red containers at Campus

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Two treatment modules in form of modified shipping containers (6m x 2,4m x 2,5m) have arrived at Campus Ultuna and will house the larvae production for our animal feed projects.

One module (=first container) is designed to process the feed for the BSF larvae. This module consists of an area for milling and storing the feed stuff and washing the used treatment boxes. In the same module also the harvesting, washing and drying of the larvae is taking place.

The other module (=second container) is holding the treatment units, 22 racks with 11 boxes each. Each box itself can yield up to 2kg larval biomass reared on feedgraded organic sidestreams. The containers are well insulated against the current outdoor conditions of up to -15°C and a strong ventilation keeps the indoor environment at optimal conditions.

In future, the two modules can be moved and placed to any area with high waste generation. The modules each need a connection to electricity (32 amp) but only one of the modules need a connection to water and sewage.

The aim is to produce feed for our 5FiskiDisk project, rearing the larvae on bread and vegetable waste. For the chicken project, we will continue one of our projects from summer 2020 and will provide a total of 320 kg live larvae to the hens.

The project will use larvae provided by the fly colony at the SLU campus.

Tobias Eisert – new intern in the Black Soldier Fly lab

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My name is Tobias Eisert. Since August 2020 am I in Uppsala as an exchange student. At my home university in Kassel/Germany am I studying Ecological Agriculture Sciences and I am about to finish my bachelor’s degree. One of my main interests regarding my studies are sustainable agriculture practices. For me, a functioning nutrient cycle is an important part of improved sustainability in the agricultural sector. The two-month long internship in the Black Soldier Fly Larvae lab gives me the opportunity to get some insights into this specific topic of BSFL composting but also more general in data collection, planning and carrying out of experiments.

Dried urine fertilizer applied with seeder!

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We are making history! Our dried urine was applied with a seeder while planting barley. This could be the first time that urine fertilizer was applied in such a way. The fact that we are able to produce a urine based fertilizer that is usable with conventional farming equipment is very exciting. We have three treatments: no fertilizer, conventional fertilizer and urine fertilizer. The urine fertilizer has 7.2 % nitrogen and we applied 100 kg N per ha.

Closing the cycle with our new toilet system

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At VA SYD’s head office, our innovative toilet system is now being installed to dry the urine to solid fertilizer, directly under the toilet. By sorting out the urine, most of the nutrients can be recycled from the sewage. We, researchers, at the Swedish University of Agricultural Sciences (SLU) have been developing the new technology, which will be tested in Malmö and Lund, within the REWAISE project.

Continue reading Closing the cycle with our new toilet system

Using MgO for Alkaline Dehydration of Human Urine Collected in Source-Separated Sanitation Systems

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We recently published a new paper on the use of Magnesium Oxide as an alkaline substrate for dehydrating urine in the journal Frontiers in Environmental Science.

https://www.frontiersin.org/articles/10.3389/fenvs.2020.619901/full

Abstract: Fresh human urine, after it is alkalized to prevent the enzymatic hydrolysis of urea, can be dehydrated to reduce its volume and to produce a solid fertilizer. In this study, we investigated the suitability of MgO to alkalize and dehydrate urine. We selected MgO due to its low solubility (<2 gL−1) and relatively high saturation pH (9.9 ± 0.2) in urine. Using a laboratory-scale setup, we dehydrated urine added to pure MgO and MgO mixed with co-substrates (biochar, wheat bran, or calcium hydroxide) at a temperature of 50°C. We found that, dehydrating urine added to a mixture of MgO (25% w/w), biochar, and wheat bran resulted in a mass reduction of >90% and N recovery of 80%, and yielded products with high concentrations of macronutrients (7.8% N, 0.7% P and 3.9% K). By modeling the chemical speciation in urine, we also showed that ammonia stripping rather than urea hydrolysis limited the N recovery, since the urine used in our study was partially hydrolyzed. To maximize the recovery of N during alkaline urine dehydration using MgO, we recommend treating fresh/un-hydrolysed urine a temperature <40°C, tailoring the drying substrate to capture NH+4 as struvite, and using co-substrates to limit the molecular diffusion of ammonia. Treating fresh urine by alkaline dehydration requires only 3.6 kg MgO cap−1y−1 and a cost of US$ 1.1 cap−1y−1. Therefore, the use of sparingly soluble alkaline compounds like MgO in urine-diverting sanitation systems holds much promise.

Contact: Prithvi Simha

Global survey of food consumer attitudes towards urine recycling

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The findings from our multinational study that surveyed the attitudes of about 3800 people from 16 different countries, are now published in Science of the Total Environment and available here:  https://doi.org/10.1016/j.scitotenv.2020.144438.

Highlights:

– Cross-cultural & country-level factors explanatory of respondent attitudes identified
– Respondents had positive intention overall but were unwilling to pay price premiums
– Social norms and cognitive awareness of urine’s benefits & risks featured strongly
– Building consumer trust via context-specific messaging can improve acceptance

Our main findings are best summarised by this picture below, which shows the strengths of association for factors explaining attitude of food consumers towards human urine as fertiliser. Factors are grouped by demographics, social norms, benefit/risk perception, substances that respondents believed are normally excreted in urine, and environmental outlooks. Dots are proportional and indicate the strength of association (Cramér’s V values); dashes indicate categories that could not be analysed due to insufficient data.

Picture inserted shortly.

Contact: Prithvi Simha

New project: beer production fertilised with urine!

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The Urine Drying team at SLU (together with Sanitation360, Spiran and Gotlands Bryggeri) have been awarded 2.9 MSEK from JTI to test using our dehydrated urine as a fertilizer for barley destined for beer production.  The objective of the project is to produce a tailored dry fertilizer from urine and a new, more sustainably produced, beer that tastes exactly the same as conventional produced beer. 

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Guide to Sanitation Resource Recovery Products & Technologies published!

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We are very pleased to share with you the 1st edition of the Guide to Sanitation Resource Recovery Products & Technologies. The Guide is a popular science publication that gives an overview of the possible resources that can be recovered and provides guidance on treatment processes to achieve safe products for reuse. The specific objectives of this document are:

  1. To expose the user to a broad range of recovered sanitation products and innovative treatment technologies.
  2. To help the user to design functional solutions for resource recovery by illustrating the linkages between sanitation inputs, treatment technology and the recoverable products.
  3. To provide an overview of basic information regarding design aspects, operational requirements, and health, safety and social considerations related to resource recovery technologies and products.
  4. Describe and fairly present technology-specific advantages and disadvantages.

The Guide to Sanitation Resource Recovery Products and Technologies is primarily a reference book. It is intended to be used by engineers, planners, end-users, researchers, technology developers, sanitation entrepreneurs, non-governmental organisation (NGO) staff and students who are interested in creating circular systems for resource use. It aims to support and enable decision making for increased resource recovery by providing information on key decision criteria for a range of recovered products and treatment technologies, thus highlighting the diversity of options available for resource recovery.

Links to download the guide:

https://pub.epsilon.slu.se/21284/

https://www.susana.org/en/knowledge-hub/resources-and-publications/library/details/4008

Continue reading Guide to Sanitation Resource Recovery Products & Technologies published!

Chea Eliyan’s one year follow-up seminar

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On the 9th of December, Chea Eliyan had her one-year follow-up seminar. She presented her research about resource recovery from faecal sludge in Phnom Penh, focusing on the results from the first two studies about faecal sludge characterization and quantification. She preliminary concluded that faecal sludge generation in Phnom Penh is at the increasing trend. The two natural wetlands around the city play a key role as a faecal sludge receiving reservoir before discharging to the rivers. Nutrients and organic matters level in faecal sludge is correlated with the connectedness of containment to the drainage but not by the type of containment. She also included the proposed approaches for her next two studies. The seminar ended with many interesting questions about sanitation challenges in Phnom Penh and the research.

Following the stricter recommendations about Covid-19, there were only four persons in a large room, and around 22 more participated online via Zoom.