**3. Drinking water consumption in Cracow: an assessment from sustainable development perspective**

In this case, the AHP method is used to assess, from a sustainable development perspective, the current consumption model for drinking water in Cracow. It assesses the economic consequences for the average city resident who decides to drink bottled water. The total energy demand for the production, distribution and consumption of bottled water is estimated and is compared to the household energy consumption.

The healthy lifestyle trends and the lack of trust in the quality of tap water result in mass consumption of bottled water. The problem is particularly significant in rich cities, which are visited by large numbers of tourists and also in academic cities, populated by young people who are trend setters, like Cracow. Such a behavior also has consequences from the sustainable development perspective.

The general goal of this case study is to develop a tool for the municipal decision makers to measure the efficiency of policy toward bottled water drinkers.

The environmental impact for the current water consumption model in Cracow is estimated by summing the waste reaching landfills, energy consumption, carbon dioxide emission, and Eco-indicator 99 H/A points. These estimates were calculated based on the data in the reviewed literature revised for the actual quantities of consumed bottled water and bottle recycling levels in Cracow. The potential environmental savings for the city related to an annual reduction of one liter of bottled water consumed by an average resident is also calculated. The different water consumption scenarios are assessed using the AHP to see how compliant they are with sustainable development.

The concept of sustainable development can be considered on three levels: ecological, social and economic. However, a problem arises with how to measure sustainable development for such an activity when the negative effects on an economic and ecological level are partially compensated for on a social level. Russel [25] suggests that energy-intensity and materialintensity of comparable products or processes serve as sustainability indicators. Life-cycle assessment (LCA) is a tool which enables an assessment of material and energy intensity of tap and bottled water preparation as well as an assessment of the impact on an ecological level. In this case, the authors tried to quantify how much bottled water is drunk in Cracow and then using American and Swiss LCA analysis, assess the actual environmental costs of such consumption for the city and its residents. Thanks to LCA, it is also possible to estimate how the environment and economy will change if an average resident reduces his/her consumption of bottled water by one liter annually. A total assessment method is also presented from the perspective of sustainable development for each of the water consumption scenarios. For the total assessment, the multicriteria AHP was used.

#### **3.1. Economic consequences for the present water consumption model**

Generally, the sensitivity analysis shows that the biggest impact on the final score have the weights assigned at the top level of hierarchy (natural environment, manmade environment,

The AHP method combined with the IWM-1 model allowed the broad and thorough compar‐ ison of two different waste disposal systems. In this case, the system based on incineration looks like a better solution and shows superior environmental performance. This good environmental performance is the result of "avoided emissions," thanks to material and energy recovery. The economic performance of the traditional landfilling system is better than the performance of system based on incineration. The overall evaluation shows that the city should build the incinerator and implement advanced recycling programs. These conclusions are in tune with the common trends and regulations. Thanks to the integration of the AHP and IWM-1, the obtained results are clear and detailed simultaneously. This is a quality very much

**3. Drinking water consumption in Cracow: an assessment from sustainable**

In this case, the AHP method is used to assess, from a sustainable development perspective, the current consumption model for drinking water in Cracow. It assesses the economic consequences for the average city resident who decides to drink bottled water. The total energy demand for the production, distribution and consumption of bottled water is estimated and

The healthy lifestyle trends and the lack of trust in the quality of tap water result in mass consumption of bottled water. The problem is particularly significant in rich cities, which are visited by large numbers of tourists and also in academic cities, populated by young people who are trend setters, like Cracow. Such a behavior also has consequences from the sustainable

The general goal of this case study is to develop a tool for the municipal decision makers to

The environmental impact for the current water consumption model in Cracow is estimated by summing the waste reaching landfills, energy consumption, carbon dioxide emission, and Eco-indicator 99 H/A points. These estimates were calculated based on the data in the reviewed literature revised for the actual quantities of consumed bottled water and bottle recycling levels in Cracow. The potential environmental savings for the city related to an annual reduction of one liter of bottled water consumed by an average resident is also calculated. The different water consumption scenarios are assessed using the AHP to see how compliant they are with

The concept of sustainable development can be considered on three levels: ecological, social and economic. However, a problem arises with how to measure sustainable development for such an activity when the negative effects on an economic and ecological level are partially

economic impact) and the weights assigned to category "impact on soil."

66 Applications and Theory of Analytic Hierarchy Process - Decision Making for Strategic Decisions

sought by the decision makers.

**development perspective**

development perspective.

sustainable development.

is compared to the household energy consumption.

measure the efficiency of policy toward bottled water drinkers.

An average Polish citizen drinks 72.4 liters of bottled mineral water annually [26]. Since most people who drink bottled water have a secondary or university education and reside in cities [27], it can be assumed that a resident in Cracow annually drinks 80 liters of bottled water.

A survey of water prices carried out in one of the supermarkets in Cracow showed that bottled water is about 500 times more expensive than tap water. Considering that a person should drink 1.5 liters of water daily, a resident of Cracow drinks approximately 548 liters of water annually, of which bottled water amounts to at least 80 liters (15%). Consequently, a resident of Cracow pays between 53 zloty and 24.22 zloty annually for bottled water whilst the remaining 85% of water drunk costs just 1.60 zloty.

#### **3.2. The effect of bottled water consumption on the natural environment**

One of the main burdens on the natural environment associated with the consumption of bottled water is its energy-intensity and the waste produced. Currently 95% of the bottled water sold in the USA and over 90% in Poland is in bottles manufactured from PET [28].

Energy is required for PET and bottle manufacture, water treatment, transportation of bottled water, chilling the water, and maintaining it at low temperature. The energy demand for bottle production depends on bottle size. For a one liter bottle weighing 38 grams, about 4 MJ of energy is required [28]. The energy required for the treatment of drinking water depends on the technology and the degree of pollution. For example, ultraviolet disinfection requires only 10 kWh/million liters, but the energy required for reverse osmosis can reach up to 1600 kWh/ million liters or more as in the case of sea water desalination [29].

The transportation's energy demand depends on two factors: distance and means of transport. The vehicles used in Poland have a medium energy demand between 3.5 and 6.8 J/(kg km) [29]. **Table 5** shows the total estimated energy demand for bottled water [28].

In this analysis, the energy requirements for the long-distance transportation of water through the pipeline or from deep boreholes have not been taken into account. It is assumed that water is first treated and then poured into plastic PET bottles, capped, labeled, and packed in a bottling plant. Then it is distributed into shops and chilled before consumption. Based on these assumptions, the total energy required for bottled water varies between 5.6 and 10.2 MJ/liter. For comparison, tap water requires on average 0.005 MJ/liter for treatment and distribution [29]. This means consumption of bottled water is between one and two thousand times more energy intensive compared to that of tap water.


**Table 5.** Total energy demand for the production and consumption of one liter of bottled water.

#### **3.3. Waste**

It is estimated that between 100,000 and 150,000 tons of PET packaging is manufactured in Poland annually [28]. Some of it is recycled, but most ends up in a landfill. According to the estimates of Organizacja Odzysku REKOPOL (Warszawa) (REKOPOL Recovery Organisation S.A. Warsaw) currently about 40,000 tons of PET waste is collected annually [30]. Other sources estimate that 28% of plastic PET bottles are recycled in Poland [31]. In 2010, 73% of packaging waste was recycled in some form in Cracow [32]. Based on these data, one can assume that the average resident of Cracow, drinking 80 liters of bottled water in 1.5 liter bottles annually, uses 53 bottles of which 39 bottles are recycled whilst the remaining 14 end up in a landfill occupying 0.019 m3 (density of compressed plastic PET bottles is 44 kg/m3 [33] and an average bottle weighs 60 grams). For the whole of Cracow, this means 14,000 m3 of waste being sent to landfill annually.

#### **3.4. Adapting LCA analysis for the consumption of bottled water in Cracow**

To more accurately assess the effect of drinking water consumption on the environment in Cracow, two reports on a similar subject were studied: an LCA report on drinking water systems in the state of Oregon, USA [34] and a similar report for the water supply for Swiss regions [35]. In the reports, various drinking water supply scenarios were analyzed ranging from unboiled tap water to bottled water transported over long distances. Taken into account were various types of packaging (tap water, bidons, bottles), transportation (different sizes of vehicles, shipping), consumption (boiled, unboiled, chilled) and packaging waste disposal policy. Forty-eight different scenarios were analyzed in the American report and 19 in the Swiss report. It was eventually decided that the conditions in Cracow were best reflected by the scenarios in the Swiss report.


bottling plant. Then it is distributed into shops and chilled before consumption. Based on these assumptions, the total energy required for bottled water varies between 5.6 and 10.2 MJ/liter. For comparison, tap water requires on average 0.005 MJ/liter for treatment and distribution [29]. This means consumption of bottled water is between one and two thousand times more

68 Applications and Theory of Analytic Hierarchy Process - Decision Making for Strategic Decisions

**Stage Energy demand (MJth) Percentage** Manufacture of plastic PET bottle 4 39–71% Water treatment 0.0001–0.02 0–0.3% Bottling and labeling 0.01 0–0.1% Transport—dependent on distance and type 1.4–5.8 25–57% Chilling 0.2–0.4 3–9% Total 5.6–10.2 100%

It is estimated that between 100,000 and 150,000 tons of PET packaging is manufactured in Poland annually [28]. Some of it is recycled, but most ends up in a landfill. According to the estimates of Organizacja Odzysku REKOPOL (Warszawa) (REKOPOL Recovery Organisation S.A. Warsaw) currently about 40,000 tons of PET waste is collected annually [30]. Other sources estimate that 28% of plastic PET bottles are recycled in Poland [31]. In 2010, 73% of packaging waste was recycled in some form in Cracow [32]. Based on these data, one can assume that the average resident of Cracow, drinking 80 liters of bottled water in 1.5 liter bottles annually, uses 53 bottles of which 39 bottles are recycled whilst the remaining 14 end up in a landfill occupying

(density of compressed plastic PET bottles is 44 kg/m3 [33] and an average bottle

To more accurately assess the effect of drinking water consumption on the environment in Cracow, two reports on a similar subject were studied: an LCA report on drinking water systems in the state of Oregon, USA [34] and a similar report for the water supply for Swiss regions [35]. In the reports, various drinking water supply scenarios were analyzed ranging from unboiled tap water to bottled water transported over long distances. Taken into account were various types of packaging (tap water, bidons, bottles), transportation (different sizes of vehicles, shipping), consumption (boiled, unboiled, chilled) and packaging waste disposal policy. Forty-eight different scenarios were analyzed in the American report and 19 in the Swiss report. It was eventually decided that the conditions in Cracow were best reflected by

of waste being sent to landfill

**Table 5.** Total energy demand for the production and consumption of one liter of bottled water.

weighs 60 grams). For the whole of Cracow, this means 14,000 m3

**3.4. Adapting LCA analysis for the consumption of bottled water in Cracow**

energy intensive compared to that of tap water.

**3.3. Waste**

0.019 m3

annually.

the scenarios in the Swiss report.

**Table 6.** Energy consumption and greenhouse gas (GHG) emissions for different water consumption scenarios for Cracow.

This report envisages nine tap water supply scenarios, out of which four assume water consumed directly from the tap, without chilling or carbonation. The differences between these scenarios are related to the source of the water and consequently to its treatment. The scenarios cover water from abstraction intakes typical for Switzerland (Kr.1), Europe (Kr.2), Swiss rural areas (Kr.3) and Swiss urban areas (Kr.4). In Cracow, each abstraction intake uses different water treatment technology [36]. They all have coagulation, sedimentation and disinfection stages. Since surface water is the source for both Zurich and Cracow, i.e., water having similar parameters, it can be assumed that the water treatment processes have a similar burden on the natural environment in both cities. As for bottled water, the Swiss report assumes 10 scenarios depending on the location where the water is produced (Switzerland, Europe), vehicle transportation distance (from 50 to 1000 km), the distribution method to the households (from 0 to 10 km by delivery van), the type of water (carbonated, still), drinking temperature (chilled, not chilled), packaging (1.5 liter PET, 18.9 liter demijohn for recycling, 1 liter glass bottle for recycling). The But.5 scenario seems to be a good choice for the water consumption model for Cracow. Based on unit indicators estimated in the Swiss report and assuming that 756,186 residents drink 1.5 liters of water daily, the annual consumption of primary energy and greenhouse gas emissions has been estimated (see **Table 6**).

**Figure 8.** Economic and environmental impact for different drinking water consumption scenarios in Cracow.

**Table 6** shows that the environmental impact depends on the water consumption scenario.

areas (Kr.3) and Swiss urban areas (Kr.4). In Cracow, each abstraction intake uses different water treatment technology [36]. They all have coagulation, sedimentation and disinfection stages. Since surface water is the source for both Zurich and Cracow, i.e., water having similar parameters, it can be assumed that the water treatment processes have a similar burden on the natural environment in both cities. As for bottled water, the Swiss report assumes 10 scenarios depending on the location where the water is produced (Switzerland, Europe), vehicle transportation distance (from 50 to 1000 km), the distribution method to the households (from 0 to 10 km by delivery van), the type of water (carbonated, still), drinking temperature (chilled, not chilled), packaging (1.5 liter PET, 18.9 liter demijohn for recycling, 1 liter glass bottle for recycling). The But.5 scenario seems to be a good choice for the water consumption model for Cracow. Based on unit indicators estimated in the Swiss report and assuming that 756,186 residents drink 1.5 liters of water daily, the annual consumption of primary energy and

70 Applications and Theory of Analytic Hierarchy Process - Decision Making for Strategic Decisions

**Figure 8.** Economic and environmental impact for different drinking water consumption scenarios in Cracow.

greenhouse gas emissions has been estimated (see **Table 6**).

In reality, water consumption in Cracow is a mixture of scenarios. About 15% of water (80 liters annually) is drunk as bottled water, which approximately corresponds to scenario But. 5, whilst the remainder is drunk as tap water which corresponds to scenario Kr.4 or Kr.6. Using scenarios Kr.4 and But.5 as the base, the impacts of the intermediate scenarios on the environ‐ ment were estimated. The results are shown in **Figure 8**.

**Figure 8** shows the environmental impact of different bottled water scenarios. If the bottled water consumption increases, all the environmental impact parameters increase very sharply. These charts can be helpful in estimating the expected impacts when changes to the water consumption model are made. The impact of reducing consumption of bottled water by one liter on the global environment and the city was also estimated. These estimates are both citywide and for one resident. The results are shown in **Table 7**.

**Table 7** shows, for example, that the municipal policy which reduces the bottled water consumption by one litter per person results in 3202 GJ energy savings and saves 181 m3 of the landfill's space. The impact on the environment is measured using Eco-indicator 99 H/A points. Eco-indicator 99 H/A points are used primarily to compare different scenarios and 1000 points have been defined as the annual environmental load of an average European citizen. It is estimated that the impact on the environment is 3.93 × 10−5 points when consuming 1 liter of tap water. However, for bottled water it is 463 times greater at 1.82 × 10−2 points.


**Table 7.** Environmental impact of a one liter reduction in the consumption of bottled water.

#### **3.5. Evaluation of the water consumption model in Cracow from a sustainable development perspective**

The evaluation of individual water consumption models, from a sustainable development perspective, requires an analysis of these models with consideration to their effect on society, the natural environment and economic impact [37, 38]. The next stage is to work out the individual criteria and select the comparison method. The AHP is one of the universal comparison methods which can be used to compare products or processes from a sustainable development perspective [39].

**Figure 9.** Hierarchical tree of criteria for AHP analysis.

In the case of water consumption in Cracow, four potential scenarios were considered by the authors of the report [4], each differing in the percentage of bottled water of the total water consumed. Scenarios where bottled water constituted, 0%, 15%, 20% and 50% of the water drunk were analyzed. On the basis of the available criteria, a hierarchical tree of criteria (**Figure 9**) was constructed and using the described method earlier, the degree of compliance with individual criteria for each scenario was evaluated (**Table 8**). Minimum and maximum values in each category were assigned to the scenario where bottled water consumption was 0 and 100%, respectively. As a social criterion, the taste of water was assigned between 0 and 10 points. The same satisfaction level from drinking water was assigned to all scenarios since in reality both professionals and amateurs find it difficult to distinguish the source the water originates from [28]. The authors of the article assigned the weightings to individual criterion in accordance with the AHP procedure, comparing individual criteria pair-wise. The process of assigning was the result of experts' discussion. The Web-HIPRE application supplied by the Helsinki University of Technology was used for analyses [24].


**Table 8.** Degree of compliance for individual criterion for various water consumption scenarios.


#### **Table 9** and **Figure 10** show the results for the AHP analysis.

**Figure 9.** Hierarchical tree of criteria for AHP analysis.

Helsinki University of Technology was used for analyses [24].

**Criteria Unit Scenarios analyzed (% of bottled water**

Eco-indicator 99 H/A points

Energy consumption

Waste m3

Environmental impact

**consumed)** 

**Table 8.** Degree of compliance for individual criterion for various water consumption scenarios.

**0% 15% 20% 50%**

GHG emissions kg CO2/capita 0.22 16.03 21.86 54.31 0.22 108.41

Cost PLN/capita 1.88 134.94 184.00 457.19 1.88 912.50

Taste points 5.00 5.00 5.00 5.00 0.00 10.00

MJ eq/capita 7.45 356.00 485.57 1 202.75 7.45 2398.05

/capita 0.00 0.02 0.03 0.07 0.00 0.13

0.02 1.47 2.01 4.99 0.02 9.96

**Minimum Maximum**

In the case of water consumption in Cracow, four potential scenarios were considered by the authors of the report [4], each differing in the percentage of bottled water of the total water consumed. Scenarios where bottled water constituted, 0%, 15%, 20% and 50% of the water drunk were analyzed. On the basis of the available criteria, a hierarchical tree of criteria (**Figure 9**) was constructed and using the described method earlier, the degree of compliance with individual criteria for each scenario was evaluated (**Table 8**). Minimum and maximum values in each category were assigned to the scenario where bottled water consumption was 0 and 100%, respectively. As a social criterion, the taste of water was assigned between 0 and 10 points. The same satisfaction level from drinking water was assigned to all scenarios since in reality both professionals and amateurs find it difficult to distinguish the source the water originates from [28]. The authors of the article assigned the weightings to individual criterion in accordance with the AHP procedure, comparing individual criteria pair-wise. The process of assigning was the result of experts' discussion. The Web-HIPRE application supplied by the

72 Applications and Theory of Analytic Hierarchy Process - Decision Making for Strategic Decisions

**Table 9.** AHP scores for the drinking water problem in Cracow according to sustainable development criteria.

**Figure 10.** AHP scores for the drinking water problem in Cracow according to sustainable development criteria.

In accordance with the accepted procedure, the scenario which assumes drinking only unboiled tap water has an overall score of 0.953 where the maximum score is 1. This is almost a perfect solution. However, the scenario where 50% of water drunk comes from plastic PET bottles scores 0.495. A sensitivity analysis shows that when the weightings are changed, the overall score for the individual scenarios also changes, but their relative ranking remains unchanged [4]. The current water consumption scenario for Cracow has an overall score of 0.820 and is 14% worse than the best scenario from the sustainable development perspective. The environmental impact, particularly when measured using Eco-indicator 99 H/A points is the most important criterion for Level I.

It is obvious that drinking safe tap water and not bottled water is superior to the person's economy and to the environment. The conducted AHP analysis shows measurably the size of this superiority. It also shows how much progress can be achieved in the city if tap water drinking becomes more common. This is particularly important in town such as Cracow which plans to organize big social events such as the World Youth Day in 2016 or the Olympic Games in the future. Thanks to the AHP, the impact of water drinking pattern is precisely measured in all selected criteria. This allows individuals and decision makers to compare the results of very different municipal policies. For example, the energy savings obtained, thanks to municipal program of building insulation, can be compared with the results of the bottled water consumption reduction program. The results of the conducted analysis can be used by the decision makers to estimate results and to make appropriate proposals on policy actions toward bottled water drinkers.
