Keywords

1 Introduction

Climate change on earth and the way people live on earth reduce the quality of drinking water sources. In some areas on the ground there is a large shortage of drinking water supplies (Chalchisa et al. 2017). According to Roy et al. (2015), in the US there has recently been a greater emphasis on quality supply of drinking water by water companies. Empirical research (Powell and Yurchenko 2019) points to a dynamic picture of the development of private security in urban drinking water.

Designing new and reconstruction existing water supply networks are based on water demand. In particular, the value of demand of drinking water by inhabitants and workers of industrial enterprises (daily water consumption of the residential sector) will influence the determination of optimal diameters of pipelines. Recently, Ukrainians are taking less water from water supply networks due to the increasing tariffs for centralized water supply and sewage. Most of the existing water supply networks in Ukraine are designed for a higher amount of water flow in the pipes, which causes a decrease in the velocity of water, an increase the duration of stay of water in the network and deterioration of water quality. The overheated diameters of the pipes of the distribution network are the reason for the deterioration of the hydraulic performance of its work (Matsiyevska 2015; Goyal and Patel 2015).

Reduction of water consumption and rational use of water is one of the priority tasks of humanity today. A comparison of the current norms of drinking water consumption in Ukraine 100–285 l/day per one inhabitant (SBN V.2.5-64 2012; SBN V.2.5-74 2013) with the previous 125–350 l/day per one inhabitant (SN&R 2.04.02-84*) indicates their decrease by about 25%. In other countries, the average value of specific water consumption in residential buildings fluctuates between 150 and 200 l/day per inhabitant (Novitska and Genich 2014). In particular, l/day per inhabitant: Norway – 175; Austria – 165; Latvija – 170; Estonia – 165; Finland – 151; Lithuania – 140; Spain – 126; Sweden – 194; Belgium – 108 (Maslak et al. 2014).

2 Aim

The aim of the research is to analyze the water demand for different categories of consumers in Ukraine and the Slovak Republic.

3 Method

The research methodology consisted of comparative analysis of the water demand for different categories of consumers in Ukraine and the Slovak Republic, and analysis of calculation results of the total daily water flow rate from the water supply network of the settlement (without taking into account the water demand for fire extinguishing).

4 Results

The values of the estimated daily water demand (average per year) for different consumers of the two countries are given in Tables 1 and 2.

Table 1. Drinking water daily demand (average per year), l/day per inhabitant
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Table 2. Estimated daily water demand (average for year) l/day per unit of measurement
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The daily drinking water demand is indicated in Table 1 in a certain range of values because the territory of Ukraine according to architectural and construction climatic conditions is divided into four districts (SSTU-N B V.1.1-27 2010). For further calculations, the northwestern architectural and construction climatic region of Ukraine (district I) has been selected.

In Ukraine the average daily rate of water consumption per inhabitant is 25–60 l/day for residential areas with water consumption from standpipe water supply point (SBN V.2.5-74 2013).

Some standards of water consumption of the Slovak Republic are not taken into account in Ukraine. The water demand can be reduced by 25% if the consumer lives in a mansion house, or water consumption is accounted for separately for each apartment, or a portion of the apartments is not connected to the sewage network. For apartments in a mansion house with over-standard sanitary equipment (for example, a swimming pool), the water demand is increased by 15% (Decree no. 684 2008).

The analysis of Table 1 shows that Ukrainian (taking into account the architecturally-structural and climatic regionalization of the territory of Ukraine) daily water demands (per year) exceed Slovakian by: up to 35% for residential houses with water supply and sewage without baths; from 11% to 74% for houses with local heaters of water; from 59% to 96.5% for houses with hot water supply.

In Ukraine, the demand of drinking water per worker at industrial enterprises is: ordinary (cold) industrial room, 25 l/shift; workshops with a heat output of more than 85 kJ per 1 m3/h (hot industrial room), 45 l/shift. In addition, for enterprises with a special sanitary regime, taking into account water consumption for one shower q = 500 l/h. It is believed that the employees of the enterprises shower for 45 min after the shift (SBN V.2.5-64 2012).

Some specific water needs for direct use in the Slovak Republic different from Ukrainian: 1 person: for drinking, 5 l/shift; for the kitchen, 25 l/shift. Specific demand in water for indirect use (washing, showering): simultaneously hot and dirty work, 220 l/shift; work with dirty operations and dusty operations or hot and clean operations, 120 l/shift; A company with a purely clean operation, 50 l/shift (Decree no. 684 2008).

Estimated water demands are shown in Table 2 for the main consumers and include all additional consumption (for maintenance staff, showers for maintenance staff, visitors, room cleaning, etc.). There are increasing coefficients with range from 1.1 to 1.2 for the 3rd and 4th climatic regions of Ukraine.

The analysis of Table 2 shows that the divergence of the values of estimated water daily demand (average for year) for the vast majority of consumers is not significant.

Output data and the results of calculating the total daily water consumption from the water supply network of the settlement (without water consumption for fire-fighting) are given in Tables 3, 4, 5 and 6. The calculations were carried out on the basis of normative documents for Ukraine (SBN V.2.5-64 2012) and the Slovak Republic (Decree no. 684 2008).

Table 3. Daily water consumption in residential buildings
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Table 4. Daily drinking water consumption in industrial enterprises
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Table 5. Daily water consumption on watering surface
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Table 6. Total daily water consumption from water supply networks
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Two levels of improvement of residential buildings in the settlement are adopted: (1) with water supply, sewage and baths with local water heaters; (2) with centralized hot water supply and baths with a length of more than 1500 mm. Output data and results of calculating the daily water consumption of the inhabitants of the city are shown in Table 3.

Industrial enterprises are within the territory of the city. We accept that the flow of water to the technological needs of industrial enterprises is constant throughout the year and the same for both Ukraine and the Slovak Republic. Therefore, in further calculations and comparisons it is not taken into account.

Output data and results of calculating the daily consumption of drinking water by industrial enterprises are shown in Table 4.

In the Slovak Republic, the average daily water demand is 45% lower than in Ukraine. Also, the maximum daily water requirement is 40% lower.

In selected industrial plants in Ukraine, the annual water demand is only 5.64% less than in the Slovak Republic.

Output data and calculated results of the daily consumption for irrigation of greenery and sprinkling of street surfaces are shown in Table 5.

For irrigation of greenery and sprinkling of street surfaces in Ukraine there is a yearly need of 42.86% more than in the Slovak Republic.

Total daily water consumption from water supply settlement networks are shown in Table 6.

From the results shown in Tables 3, 4, 5 and 6 we can state, that for the selected sample, the total average water demand in Ukraine is higher than in the Slovak Republic by 44.41%. The difference between results for two countries in total maximum water demand is 39.88%, in minimum water demand is 9.98%.

5 Scientific Novelty and Practical Significance

The obtained results outline directions for further research: studying the structure of water consumption for different needs; scientific substantiation of the drinking water demand for residents of houses and workers of industrial enterprises. At the same time, the main attention should be paid to the behavior of the consumer (Romano et al. 2014; Zadeh et al. 2014).

From a practical point of view the reduction of water consumption standards will reduce the diameters of water supply networks and, consequently, substantially reduce the material content of water supply systems and save raw materials and energy resources.

6 Conclusions

Ukrainian water demand (average daily per year) of drinking water is higher than Slovakian: up to 35% for residential houses with water supply and sanitation without baths; from 11% to 74% for houses with local water heaters; from 59% to 96.5% for houses with centralized hot water supply. For the majority of other consumers, the divergence of normative water consumption is insignificant. In the Slovak Republic, the average daily water demand is 45% lower than in Ukraine. Also, the maximum daily water requirement is 40% lower.

In selected industrial plants in Ukraine, the annual water demand is only 5.64% less than in the Slovak Republic.

For irrigation of greenery and sprinkling of street surfaces in Ukraine there is a yearly need of 42.86% more water than in the Slovak Republic.

From the results shown in Tables 3, 4, 5 and 6 we can state, that for the selected sample, the total average water demand in Ukraine is higher than in the Slovak Republic by 44.41%, maximum water demand by 39.88%, minimum water demand by 9.98%.