Addressing wastewater infrastructure needs in urban informal settlements must simultaneously address legacies of past failures, current aspirations and constraints, as well as increasingly changing needs related to global environmental change. This study applied the Sustainable System-of-Systems framework for ergonomics and human factors to gain a better understanding of how small in-situ constructed wetlands could be a form of greywater treatment infrastructure in an informal settlement. Using 24 months of interviews, surveys, workshops and photo-ethnographic observations, we identified that the rapidly changing nature of parent (e.g. residency transience and land ownership) and sibling (e.g. housing and drinking water) systems put pressure on the target wetland system to adapt, often decreasing its capacity to deliver the service of water cleaning. Greywater treatment was not a common goal among stakeholders involved in the nested hierarchy system which likely contributed to the constructed wetlands needing to adapt to remain relevant. Practitioner summary: The value of the Sustainable Systems-of-Systems framework for ergonomics/human factors professionals in determining the sustainability of an ergonomics/human factors intervention is demonstrated using a greywater treatment system case study for an urban informal settlement. Understanding the variety of stakeholder goals and the pace of change in related systems was key to a sustainable intervention.

This document accompanies an art & science collaborative exhibit exploring how urban agriculture can contribute to sustainable resource flows to support food production, recreation, and water quality.

Denna broschyr har tagits fram i anslutning till en utställning där en forskargrupp samverkar med en konstnär. Den utforskar hur stadsodling kan bidra till hållbara resursflöden och därigenom stödja produktion av livsmedel, rekreation och god vattenkvalitet.

Safe recycling of nutrients found in human excreta back to agriculture is an important component of a circular economy that can protect waterways and stabilize food prices. Although many technological advances for the recovery of these nutrients exist, large-scale implementation is lacking. A commonly cited barrier is a lack of acceptance of fertilizers from human excreta and for food products grown with such fertilizers. 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. 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. Acceptance of wastewater-derived fertilizers was largely dependent on perceived risks, especially the fate of pharmaceutical residues. 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.

There is a significant amount of evidence highlighting the health, wellbeing and social benefits of gardening during previous periods of crises. These benefits were also evident during the COVID-19 pandemic. This paper presents a narrative review exploring gardening during the early stages of the COVID-19 pandemic to understand the different forms of gardening that took place during this crisis and key elements of this activity. Research about gardening during the pandemic focused on food (in)security and disrupted food systems, the health and wellbeing benefits of gardening, and the social dimensions of gardening. We offer three vignettes of our own research to highlight key insights from local, national and international perspectives of gardening during the pandemic. The papers conclusion outlines how researchers, policy makers and public health practitioners can harness what has been learned from gardening during the pandemic to ensure these benefits are more widely available and do not exacerbate already entrenched health inequalities in society.

In this  study we have investigated the role of biogas solutions to support increased resource efficiency on the island Gotland,  including recovery and redistribution of nitrogen (N) and phosphorus (P) within the agricultural sector. First, we  analyzed the potential for  expanding energy and nutrient recovery from organic residues using biogas solutions. Our findings suggest that the biogas production could expand to 165 GWh, from the current 36 GWh (2020), with manure accounting for a potential  110 GWh biogas annually if all were digested. Comparing the nutrients contained in organic feedstock with the crop nutrient demand on Gotland showed that for N the  demand is 2.4 times higher than the supply. In contrast, the calculations showed a 137 tonnes P surplus, with distinct excess areas in the center and southern part of the island.

We then compared scenarios with different numbers (3 - 15) of biogas plants with respect to   efficient nutrient redistribution and transport costs. Spatial constraints for new plants, e.g. need for roads with a certain capacity  and permit issues, were accounted for by  adding local information to a national data set. We identified  104 potential locations (1 km$^2$ grid cells) and used an optimization model to identify the most suitable locations for minimized transport costs. Optimal  (meeting the crop demand with no excess) redistribution of all nutrients contained in the feedstock, as raw digestate from biogas plants, would result in an export of 127 tonnes of P from the island. The model results indicated that if all potential feedstock would be digested in three additional biogas plants and nutrients redistributed for optimal reuse, the total transport  cost would be 2.6 million SEK annually, excluding the costs for nutrient export from the island (3.7 million SEK). If instead 10 or 15 smaller plants would be built, the transport cost would drop to 1.8  million SEK, with the same amount of P being exported. Comparing the scenarios with different number of biogas plants (3 - 15), showed that some locations are more suitable than others in terms of distance to feedstock and

to fields with fertilizer demands. Finally, a preliminary analysis of the amount of crop residues indicated that this type of feedstock could add a substantial amount of biogas production, but more extensive analyses are needed to assess  the feasibility to realize part of that potential.

Urban agriculture has a high potential to contribute to local circular economies, for instance by using nitrogen, phosphorus, and potassium in city organic waste streams as fertilizer inputs. However, inefficient use of waste-derived fertilizers could contribute to local water quality impairment related to nitrogen and phosphorus losses. Organic waste derived fertilizers are particularly challenging from a nutrient stoichiometry perspective, making over- and under-application of a particular nutrient likely. Where, and under what conditions, urban agriculture acts as a net positive for a circular nutrient economy vs. a nutrient water quality risk remains unclear. Here we review empirical peer-reviewed studies (2000–2021) on soil- and ground-based urban agriculture with a stated concern for nutrient losses to water. Of the 20 publications retained and reviewed (out of 241 screened), only seven measured losses to waters. There were four experimental studies, of which three measured nutrient leachate losses under different garden management practices. Of the 16 studies done in real-world conditions, only four quantified losses to water as leachate; average losses spanned 0.005 to 6.5 kg ha−1 for phosphorus, and 0.05 to 140 kg ha−1 for nitrogen. 13 of the 16 non-experimental studies provided data on nutrient inputs and harvested crop outputs, which could be used to calculate garden nutrient balances—an indicator of nutrient use efficiency. Although the value ranges were large, most studied gardens showed nutrient surpluses (inputs > crop harvest) for nitrogen and phosphorus (but not potassium); these surpluses were identified as a risk for losses to water. Contextual factors such as different access to fertilizers and knowledge, along with regulations and environmental factors can help explain the wide range of balance values and nutrient losses observed. Although a large surplus of inputs was often linked to increased leachate losses, it was not always the case in the limited number of studies we identified. Our review suggests that more field studies that measure losses to waters, and document contextual factors, are needed to determine how urban agriculture may contribute to a sustainable circular economy for all three nutrients without nutrient-related water quality impairment.

Supporting low levels of animal product (meat, dairy, and eggs) consumption and food waste can significantly reduce the impacts of unsustainable phosphorus use. In addition, consuming products grown with good on-farm nutrient management practices, including phosphorus recycling can further reduce impacts. These changes can contribute to achieving multiple United Nations’ Sustainable Development Goals related to improving human and environmental health.

Biogas production through anaerobic digestion is an integral part of the transition toward a biobased and circular economy and its expansion is foreseen in many parts of the world as well as in Europe. In Sweden, a governmental inquiry suggested biogas production to be increased from about 2 TWh today to 7 TWh by 2030. This rapid expansion would require installation of several new biogas plants across the country. However, the location of biogas plants can greatly affect its business performance and there are several geographic and socio-political factors that would limit the choice of location. Through dialogue with existing biogas producing companies and a few other related actors, we identified 12 factors that are commonly considered in the site-selection of biogas plants in Sweden or are considered to be important in the years to come. These factors are grouped into those related to supply and demand (feedstock supply, biogas demand, digestate demand, and carbon dioxide demand), infrastructure and synergies (available infrastructure, adjacent existing industries), land-use and zoning (nearby housing, zoning, and historic preservation sites), and socio-political context (political strategies and goals, organizational capability, and local social acceptance). We discuss how these factors can be used under rapidly transforming conditions in Sweden through different site-selection logics and highlight the importance of spatially explicit analysis for individual or coordinated decision making in future. Our method of enquiry and analysis, and to a certain degree the factors, can be also relevant for other countries, particularly in Europe. This study paves the way for more in-depth investigation of the question of site-selection of biogas plants in Sweden; both in the direction of detailed analysis at the local level, or screening analysis on the regional or national level for improved coordinated actions.