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Life cycle assessment of small-scale constructed wetland and extended aeration activated sludge wastewater treatment system
Lopsik, K.
Abstract
Wastewater treatment plants help to reduce
negative impact on the environment by improving the
quality of effluent. Different technologies are used in
wastewater treatment, and one of the tasks is to find the
most environmentally sound option, taking into account the
use of resources and energy during construction and
operation of the treatment system. The aim of the study is
to assess environmental impacts from two different types
of small-scale wastewater treatment systems, a constructed
wetland and extended aeration activated sludge treatment
system using Life Cycle Assessment method. The system
boundaries include construction and operation phases.
Assessment has been carried out using SimaPro software
and Impact 2002+ and ReCiPe assessment methods with
characterisation and normalisation stages. The results show
that the main negative impact of constructed wetland is
caused by the construction phase and use of lightweight
expanded clay aggregate to construct the hybrid filter.
Impacts from extended aeration activated sludge treatment
system are mainly caused from the use of electricity and
the quality of the effluent, therefore, the use phase has a
larger impact on the life cycle. Since a large amount of
energy is used to produce lightweight expanded clay
aggregate, the impact of 1 population equivalent of constructed wetland is larger than the impact of extended
aeration activated sludge treatment system. Constructed
wetland dominates in human toxicity, acidification, land
use, ozone layer depletion and the use of non-renewable
resources categories. Extended aeration activated sludge treatment system dominates in categories associated with
eutrophication and ecotoxicity
Keywords
Sewage; Light expanded clay aggregate; Environmental impact; Impact 2002+; ReCiPe
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