Increased interaction between scientists and the social environment is considered to be one of the characteristics of modern science. This interaction can occur through collaboration between different sectors in society. In connection to this, the Triple Helix model claims that interaction between university, industry and public sectors, is key to modern innovation development. So far, cross-sector interaction between actors in environmental science has been scarcely studied in a scientific manner. Most studies carried out in the area have disregarded the actual practice of such collaborations and what happens in projects where these sectors interact. As this has become a common way to solve environmental problems, it is of considerable importance to gain more knowledge about this process. The objective of this research was to study and explain cross-sector collaboration. Using the interactive research method, characterised by joint learning and interaction with the participants, this was explored through two case studies. The method was well suited for studying ongoing interactions between the university, industry and public sectors. The first case was an international collaboration between representatives of the Triple Helix sectors. Here, olive-mill wastewater in Greece was the focus. The Triple Helix framework was used both on the intended analytical level and at a management level closer to the actor level of the participants. The second case was a three-year environmental research project in the Kalmar region where strong university-industry collaboration was carried out in order to find wastewater treatment solutions in the wood industry. This collaboration was extended to include more actors in the region during the process. The actual practice of these cases showed the importance of a dialogue between participants. Triple Helix can be used as an initial framework for such a dialogue through which the model is redefined by input from all sectors.

Increased interaction between science and society is recognised as one of the characteristics of contemporary science. Solving the complex environmental problems of our day also necessitate such interactions. In this thesis, theories of knowledge production and innovation, including the triple helix and Mode 2, were used to analyse and assess environmental science critically. The triple helix model claims that interaction between university, industry, and government, is essential for innovation development. The Mode 2 of science emphasises the social embeddedness of science. These theories of knowledge production are situated on a macro level. Most studies carried out about this have disregarded the interactions in practice between science and society. The aim of the thesis was to explore how these theories manifest themselves in practice. Further, the aim was to contribute to knowledge about cross-sector interactions in environmental research collaboration. Interactive research was conducted in three environmental research projects. One survey was also conducted on a national level. Results are distributed in five research papers. Firstly, the results showed that the triple helix became somethings else on a project level. Further, when working in a triple helix-based collaboration participants encountered boundaries and which could be crossed using boundary-spanning means. The use of dialogue arenas in interactive research, meaning research oriented workshops and seminars, aided both participants and the researcher to cross disciplinary and cross-sector boundaries. Solving environmental problems, using cross-sector research collaboration, necessitated the recognition of the collaborative process itself. An abstract environmental idea such as the circular economy was also found to contribute to bridging the gaps between research and society. Lastly, the research showed that environmental scientists reflect upon the relevance of their research. The scientists felt the need to provide society with relevant research and adjust their research choices due to this. This thesis ends up with a discussion about a Mode 3 of knowledge production where the democratisation of research is crucial. Here a fourth helix represents the further inclusion of society in general. A fifth helix includes the natural environment as a driver for collaboration, forming a quintuple helix which incorporates the environmental relevance into collaboration. This thesis contributes to knowledge about theories of knowledge production, cross-sector research collaboration and the role of environmental science in society.