Factors influencing actors at the interface between the socio-technical and the ecological systems: The case of on-site sewage systems and eutrophication

Abstract: Eutrophication, caused by nutrient loading, is a global environmental problem, particularly severe for the Baltic Sea. Long-term solutions rely on the ability of society to respond effectively. This involves, for example, instigating actors who have the capability to directly influence nutrient loads to take action. In Sweden, one of the substantial sources of nutrients is on-site sewage systems (OSS), that is, wastewater treatment systems for one or a few households. The aim of this thesis is to increase the knowledge about factors influencing actors that directly and indirectly influence nutrient loads from Swedish OSS by (1) Identify factors influencing homeowners’ to change OSS, and (2) Investigate the relative strength of these factors. Semi-structured interviews with homeowners and authority inspectors were used to elicit tentative conceptualizations of influencing factors. The results together with literature on pro-environmental and compliance behavior were used in the construction of a questionnaire, directed at Swedish homeowners with OSS. The analysis involved statistical methods, including principal components analysis to identify underlying motivational factors, and regression analysis to investigate the relative strength of these factors, while controlling for government and authority interventions. The result shows that authority interventions are needed to make homeowners change OSS. Informal means, such as information, will not likely lead to a large-scale transformation of OSS. They may, however, be effective in combination with more deterrent means of regulatory enforcement, such as injunctions. Such interventions are needed because of the high costs and no, or very low, benefits of changing OSS from the homeowner point of view. Furthermore, the awareness about the need to change OSS from an environmental point of view seems to be low. In this situation, homeowners are most inclined to defend their self-interest and do not act based on environmental concerns. Homeowners are more inclined to change OSS under the condition that other homeowners are cooperating.