M. Lundin et al., Life cycle assessment of wastewater systems: Influence of system boundaries and scale on calculated environmental loads, ENV SCI TEC, 34(1), 2000, pp. 180-186
Citations number
26
Categorie Soggetti
Environment/Ecology,"Environmental Engineering & Energy
Life cycle assessment (LCA) methodology was used to compare the environment
al loads from wastewater systems with different technical solutions. This s
tudy compared proposed conventional wastewater systems, both large and smal
l scale, with separation systems: one in which urine is handled separately
and one in which black water is treated in a liquid composting process. The
study showed that large economies of scale, in environmental terms, could
be gained both for the operation and for the construction phase. The separa
tion systems outperformed the conventional systems by showing lower emissio
ns to water and more efficient recycling of nutrients to agriculture, espec
ially of nitrogen but also of phosphorus. This implies that the use of sepa
ration systems could significantly reduce the need for, and hence the produ
ction of, mineral fertilizers and thus reduce the overall use of energy and
phosphate minerals. The combination of large-scale wastewater treatment an
d urine separation was found to be especially advantageous in these respect
s. It is concluded that some of the most important environmental advantages
of separation systems emerge only when models of wastewater systems are ex
panded to also include potential effects on the production of fertilizers.