Research and development related to the recovery and reuse of nutrients in human excreta and municipal wastewater has intensified over the past years, continuously unfolding new knowledge and technologies. The messy and sprawling nature of existing knowledge is one of the obstacles to taking full advantage of the potential for nutrient recovery and reuse. The goal of the project was to co-create an online evidence platform to support and encourage acceptance, implementation and upscaling of innovative and sustainable solutions to recirculate nutrients from human excreta and municipal wastewater to agriculture.

Sustaining agricultural productivity requires that nutrients taken up by crops are replenished. Recycling nutrients in human excreta to agriculture can make important contributions to more circular nutrient flows and improved food security. This research provided an overview over available nutrient recovery technologies, proposed to frame nutrient recycling from human excrta as part of the food system rather than waste management, and explored a novel way to analyze the circularity of nutrient flows in food systems.

Risk assessment (RA) and life cycle assessment (LCA) are two analytical tools commonly used to support decision making in sewage sludge management and other contexts. RA and LCA were initially developed and used by largely separate groups of specialists, but there is scope for blending elements of the two tools. This research reviewed environmental assessment case studies blending elements of RA and LCA and identified a range of opportunities and pitfalls. The work also featured an attempt to build a Life Cycle Impact Assessment (LCIA) model for human toxicity inspired by quantitative chemical risk assessment (QCRA).

Human health risks associated with the exposure to pathogens in urban water infrastructure are of common concern but had not been accounted for in life cycle assessment (LCA). This research explored the possibility to include pathogen risk in LCA. The work drew heavily from quantitative microbial risk assessment (QMRA) and helped identifying opportunities and unresolved issues when attempting to include pathogen risk in LCA.

The study of household metabolism - stocks and flows of energy, matter, and information at the household scale - seeks to support pro-environmental behaviour. This research explored ways to quantify goods purchases and waste generation at the level of individual households. This research also contributed to mapping contributions and perspectives of a various research traditions that have an interface with household metabolism, highlighting a number of controversial issues.

Phosphorus (P) is a plant nutrient of paramount importance for food security. Many current agricultural and waste management practices lead to a dispersion of phosphorus to different sinks. There is a growing awareness of the need for better P management and more circular P flows. This research mapped flows and sinks of P in Gothenburg, Sweden, for the urban water infrastructure in place in the year 2009, and for a range of possible future scenarios.

In conventional sewer networks water is used to convey human excreta to sewage treatment plants (STPs). Municipal sewer systems commonly also serve industry and hospitals, sometimes even stormwater is drained through the same pipes. It has long been proposed that separating streams at the source would provide greater opportunities for resource recovery by finding ways to minimise dilution and contamination of human excreta. This researched explored and mapped the potential for separate collection and transport of black water in the existing building infrastructure.