SUDDEN HACKATHON: How to utilize nutrients contained in sewage sludge?

08.03.2023 | Blog

Well-managed nutrient recycling promotes self-sufficiency in our food systems and lessens its environmental impact. The phosphorus retained in sewage sludge have the potential to become a sustainable source of agricultural fertilizer. Still, along with nutrients and organic matter, sludge also contains pollutants harmful to the environment, plants, and organisms, including the residues of pharmaceuticals. Safe utilization of the sewage sludge based nutrients requires  more information on the occurrence of these potentially harmful substances and their removal. 

There are many steps and stakeholders between sludge production, handling and its end use: the value chain of sludge based nutrients, understood as a socio-technical system, consists of networks of actors (collective associations, individuals, business) and institutions (regulators, processors, technical and social norms and standards), along with technological artefacts and related knowledge. Hence reaching innovative solutions requires changes that are not only technological but also organisational, economic, institutional and socio-cultural. To ensure the acceptability of the end product, there is a consensus that responsibilities and regulations need to be better resolved.

This first hackathon organized by the SUDDEN project on January 25th brought together stakeholders throughout the whole value chain of sewage sludge, from operators of wastewater treatment plants to sludge processors, farmers’ representatives, grain buyers and regulators (see illustration). The event aimed at testing the basis for a multi-stakeholder approach for innovation under the conviction that a systemic, integrated and collaborative understanding of the whole value chain is essential to avoid cognitive biases and ideas segregation. This brief post reports on the central results of this dialogue.

Consensus that nutrients from sludge could be better utilized if offset by safety concerns

Sewage sludge based nutrients could be utilized better when done safely. There was a shared need among the participants to find a compromise and stick to it when considering all possible stakeholders related to the subject. Technical solutions are needed, but systemic implications are also of great concern. Hence the participants recognize the importance of bringing together the participation of social actors, institutions and researchers to address issues of agreement and contestation. This could be possible, e.g. through a multidisciplinary, solution-oriented task force that would link to decision-making in a formatted process. 

Uncertainties raised were related to safety. In Finland, contaminants, such as heavy metals and bacteria, are well monitored and managed.However, organic pollutants, including residues of pharmaceuticals, need a more comprehensive approach as their potential risks are not fully understood — biotoxicity being among the major concerns. Unless they can be removed from sludge, these pollutants may end up into the environment, degrading its integrity and affecting the soil environment and health of our food systems through agricultural crops. Participants agreed that to ensure safety, further scientific research should consider combined inputs from social, technical and environmental perspectives.

Potential for circularity motivates the work on risk removal

The uncertainties and risks related with sludge utilization certainly call for precaution. At the same time, precaution should not be an obstacle to innovation. The value of sludge has great potential to be transformed from a waste into a reusable nutrient with embedded ethical, economic and sustainability values, including carbon-positive effects and self-sufficiency in food production.

Increased cooperation and leadership among actors through the value chain, more than just technical innovation, are needed to overcome safety concerns. Thus, the hackathon participants considered together how to implement this into action.

Suggestions from the participants included:

  • Emphasis on communication and education to better understand systemic implications. Already this short event enabled stakeholders to increase their understanding through bringing together their views and experience across disciplines. The need for funding for multidisciplinary research was also highlighted.
  • Clarification of the roles and responsibilities of all the actors involved. Starting with a broader definition of the stakeholders, there is the need to better define and possibly regulate the shared responsibilities for the safety of the end product. Questions were brought up: Who is responsible for the safety? Is it water treatment plants, the producer of fertilizers, or the farmers? Should the pharmaceutical industry share responsibilities? Should the food industry and consumers demand safety?
  • Coordinated stakeholder working groups. It is relevant to recognize which actors, intermediaries and agencies are the most involved and have the potential to drive innovation. Collaboration among all stakeholders is key for setting priorities and defining actions, and there is an opportunity for creating strategies for more systematic involvement.

The safe utilization of the nutrients retained in sewage sludge is a clear example of how socio-technical and ecological systems are intertwined: the outcomes of the pharmaceutical or chemical industry have implications for agriculture, our food systems and the health of the environment. As such, systemic problems cannot reach sustainable solutions if efforts are restricted to disciplinary and professional silos working in isolation. Our first hackathon demonstrated the benefits of bringing together the most relevant actors from the local sewage sludge value chain in an attempt to set the base for further collaboration in the future.

The first SUDDEN hackathon was organized on January 25th in Helsinki. In addition to the SUDDEN research consortium, the Ministries of the Environment and of Agriculture, Natural Resources Center (LUKE), Finnish Environment Institute (Syke), farmers, food producers, waste management, and students of the field were represented at the event. The topic was how the nutrients retained in sewage sludge could be better utilized, for example, in agriculture, but also in other fields. At the beginning of the event, four keynotes were heard: Lauri Äystö (Syke, SUDDEN); Mari Unnbom (HY), Katri Senilä (UEF/Ely center) and Elina Tampio (LUKE).

The SUDDEN Hackathons continue in May 2023 with the topic of consumer behavior.