STS - conferences, IST2012

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Institutional changes and technological dependencies as drivers and barriers to decreasing environmental pressures from decentralized large technical systems – the case of Swedish on-site sewage systems
Are Wallin, Mathias Zannakis

Last modified: 2012-03-26


The case of on-site sewage systems (OSSs) is an example of a decentralized large technical system and one of many policy-areas facing challenges on how to achieve technology transformation towards decreasing environmental pressures. In Sweden, the 700.000 OSSs are of great concern because they contribute substantially to Swedish nutrient loads and the potential for reductions in nutrient loads from OSSs is large. This paper analyzes the historical development of OSSs in Sweden, by contrasting the building up of institutions, technological change and the resulting environmental outcome in terms of the nutrient capture capability of Swedish OSS.

The development of Swedish OSSs is described as following three trajectories. First, in 1945–1960 hygiene concerns, large-scale home improvement programs and aspirations for higher living standards led to a large-scale transformation of OSSs. During this period almost half of all countryside homes got piped water and wastewater and changed from dry toilets to water closet. Thus, most of the transformation of OSSs occurred during a period when the water-based sewage systems were not constructed to achieve environmental protection. Second, environmental concerns and the strengthening of environmental legislation led to stricter regulations and slowly increasing nutrient capabilities in the late 1960s (institutional displacement). Third, since the late 1960s and onwards the OSS field has been characterized by institutional layering, meaning that new rules have been attached to existing ones. Although this has implied the strengthening of regulation, both homeowners and environmental inspectors have had problems interpreting and relating to these rules, and homeowners have not changed OSSs at a large-scale. Consequently, nutrient capture capabilities of OSS are low compared to what is necessary from an environmental perspective. We suggest that this is partly due to unintended environmental consequences of the early transformation, and the succeeding lack of effective mitigation measures because of institutional layering.