5. Results
The results of LCA states that the energy consumed for groundwater extraction is maximum while energy required for the re-distribution of the treated water is minimum. This is due to the decreasing mass flow of water throughout the phases. The results of the endpoint approach are shown in figure 1.
Model 1 has 707.83 points in total while Model 2 has 638.03 points. As compared to Model 1, in Model 2, impacts are decreased as follows – 10 % of points in the category ‘Resources’, 11 % in ‘Human health’ and 9 % in ‘Ecosystem quality’.
The results of the midpoint approach are shown in figure 2(a-e). It shows that the global warming potential of the university resident is 1.34 KgCo2Eq for water consumption. In all five categories the indicators of Model 2 are smaller than the ones of Model 1. The global warming potential decreased around 9% while there is a lower heating value of 11%. In addition, the hazard-weighted concentration was reduced by 16% and the hazard-weighted dose by 20%.
Another finding is that most impacts are caused by the product tap water used in buildings. The tap water in the buildings denotes the fresh water used by the end-users in the academic and residential areas. The impacts of the tap water used for irrigation (fresh water used for the irrigation for gardening activities) and the impact of the treated water used for irrigation is negligible. Fig. 3 shows followed by that tap water has maximum global warming potential in disposal (35.86%) followed by water extraction (35.08%) and distribution phase (29.07%). The effect of irrigation water during distribution on global warming potential is 45.38% and for extraction phase the value is 56.42% as the irrigation water goes to the earth therefore the recycling value is zero. Figure 4 shows the impact of ‘tap water used in buildings’, ‘fresh water used for irrigation’ and ‘the treated water’. It clearly shows that the impact of treated water on global warming potential is negligible and the impact of fresh tap water has 77% impact. Treated water used for irrigation is the origin of 0.01 % of the impacts only
This statement is valid for the three endpoint categories and for the two midpoint categories Climate change and Fossil depletion in both models.
As a final step, the distribution of impacts due to the life cycle phases is examined. An example of the allocation of impacts to the life cycle phases for the global warming potential of model 1 is shown in figure 4.