University of Vaasa - Vaasan yliopisto

A Vision For 2015
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The vision to be tested through the sustainability LCA comparison is: households,
companies and other organizations all over the world turn their sewage into biofuels
instead of discharging it into the environment by 2015.
This would solve two global problems at once:
1. Carbon Dioxide (CO2) emissions from fossil fuels contributing to climate
change;
2. Over-Fertilization of waterways causing sea, lake and river deaths.
In the following sections the feasibility of Tarja Ketola’s vision is tested by Tiina
Myllylä’s comparisons of expert views of the sustainability impacts of different ways
of producing, consuming and recycling biofuels.
Findings from Interviews: Biofuel Sustainability Compared
For the purposes of the empirical study, biofuels were divided into five categories:
(1) Biogases: waste;
(2) Bioliquids: different plant oils;
(3) Field biomasses: farming waste, fields and swamps;
(4) Turf: organic material;
(5) Wood-based biomasses: industrial wood residue and industrial by products.
Some of these categories overlap, but this division gives a fair picture of the different
kinds of available biofuels. The environmental, social, cultural and economic impacts
of each biofuel category will be discussed on the basis of the interviews.
Biogases
Biogases refer to constituents like methane and carbon dioxide that are produced by
the anaerobic fermentation of biological materials. Biogases are most commonly
produced from agricultural and organic waste. Sewage gas is produced through
sludge digestion in the tanks of sewage treatment plants. Landfill gas is produced
from organic residues in garbage tips (GE Energy 2009). An example of this is from
Vaasa, Finland, where the regional waste management company, Stormossen, has
converted 100% of biogas into energy (Stormossen 2007). Table 1 summarizes the
interviewees’ opinions about the environmental, social, cultural and economic
impacts of biogases at different stages of their life cycles.