for negative effects is increased. In addition, the model can
be compared to other water supply system which offers
optimization opportunities.
The researched system is a multi-product system with
three products – tap water used in buildings, tap water used
for irrigation, and treated water used for irrigation. This
results in the necessity to allocate the expenditures to the
related product. In this study the environmental impacts for
undesired co-products or residues are not counted. The
functional unit is defined as 'water supply of the campus
with 6,200 permanent inhabitants at one summer day'. With
this definition the system is able to be compared to other
water supply systems. To carry out this assessment, the
whole life cycle (including groundwater catchment, storage,
distribution, consumption, disposal, and recycling) of the
product and the required energy and chlorine production is
also taken into account. The second model simulates a
lower water flow at campus. As a consequence, energy
consumption of the whole system and chlorine demand at
the treatment plant is recalculated. Finally, only the current
expenditures on the water supply system are included. The
lifecycle of the material required for construction activities
of the infrastructure has not been considered. The inventory
analysis and the impact assessment of both the models were
conducted in the software Umberto NXT LCA. The used
assessment method is ReCiPe 2008 which combines
midpoint and endpoint approaches.
To carry out the LCA of the system two models have
been constructed. The first model (Model 1) simulates the
current state of the water supply system with 2,056,742
litres of water pumped per day and a low treatment
efficiency of the sewage treatment plant due to overload.
The second model (Model 2) assumes a reduction in the
water consumption from almost 330 litres to 270 (national
average demand for India) litres per person per day and a
sewage treatment efficiency that meets the standards, which
are necessary to produce water to tap water quality. Model
1 represents the current demand and Model 2 represents the
demand considering national average demand for India. The
current demand for the water supply is higher than the
average national demand. The results of both the models are
compared to determine the intensity of the reduction of
environmental impacts due to the related optimization
ideas. The scope of this method is to find a base for
developing efficient optimization methods.