The blue and grey water footprint of industry and domestic water supply : The blue and grey water footprint of all industrial sectors and domestic water supply for each country annually in the period 1960-2015

At this moment, two-thirds of the global population live under conditions of severe water scarcity at least 1 month a year and half a billion people in the world face severe water scarcity all year round. Increasing knowledge of freshwater abstraction and consumption could contribute to awareness, change, or a solution to the increasing freshwater abstraction and consumption worldwide. An indicator of the direct and indirect freshwater consumption of a consumer or producer is the water footprint. The water footprint is defined as the total volume of freshwater consumed to produce goods or services. Water consumption is defined as the blue water footprint and water pollution as the grey water footprint.The blue and grey water footprint of all industrial commodities and domestic water supply are treated as two whole sectors for a ten-year period in current literature. These sectors contribute approximately 8% of the total water footprint. It does not show annual variations or trends in time. However, the grey water footprint of the industry is grossly underestimated because of conservative assumptions that were made due to the lack of appropriate data on the pollutants discharged in industrial effluents. The objective of this research is to estimate the blue and grey water footprint of industrial sectors and the domestic water supply sector per country annually for the period 1960-2015. The industry is classified in different industrial sectors and divisions - Mining and quarrying, manufacturing, electricity, and construction. The domestic water supply sector is defined and treated as a whole. The blue water footprint is estimated by estimating the water consumption per current US dollar of an industrial sector and multiply it by its gross added value per country and year. For the missing data, interpolation and extrapolation based on the GDP of that country are used to complete the data for the whole period. The blue water footprint of the electricity sector is estimated by using a water consumption to MWh ratio. It turned out this sector has the largest blue water footprint and therefore the blue water footprint of the divisions within this sector are also estimated. The domestic water supply sectors are estimated by multiplying the water consumption to withdrawal ratio of 15% with the water withdrawal in this sector per country and year. The grey water footprint of both industrial and domestic sectors is estimated by multiplying new estimated dilution factors with the effluent of the sectors. These estimations are based on contaminants found in effluents of the sectors or environment around these sectors. The new dilution factors can be up to five times larger than the conservative dilution factor 1 used in other literature, which results in higher grey water footprint. The total industry had a global blue water footprint of 3.86 *1010 m3 in 1960 which increased to 3.02*1011 m3 in 2015. The construction sector had a global blue water footprint of 5.07 *106 m3 in 1960 and 2.97*108 m3 in 2015. The global blue water footprint of the manufacturing industry increased from 1.22*108 m3 in 1960 to 3.70*1010 m3 in 2015. The mining and quarrying sector had a global blue water footprint of 4.23*108 m3 in 1960 and increased to 1.92*1010 m3 in 2015. The electricity generation sector has the largest global blue water footprint every year, it was 3.72*1010 m3 in 1960 and increased to 2.42*1011 m3 in 2015 which is by far the largest blue water footprint of all industrial sectors. The global grey water footprint of the industry was 1.56*1012 m3 in 1960 and increased to 3.18*1013 m3 in 2015. The construction sector had the smallest global grey water footprint with 1.60*109 m3 in 1960 which increased to 7.87*1010 m3 in 2015. The global grey water footprint of manufacturing industry increased from 9.18*109 m3 to 3.97*1011 m3 in 2015. In 1960 the mining and quarrying industry had a global grey water footprint of 4.39*1011 m3 which increased and became the largest global grey water footprint in 1975 and eventually in 2015 it was 1.99*1013 m3. The global grey water footprint of the electricity sector was 5.52*1011 m3 in 1960 which was 5.69*1012 m3 in 2015. The domestic water supply sector had a global blue water footprint of 5.92*109 m3. This is increased to 1.10*1011 m3. The global grey water footprint of the domestic water supply is 1.53*1013 m3 in 1960 and 4.24*1013 m3 in 2015. This study contributes to science by making a distinction between blue and grey water footprint of sectors within the industry for a long period. It contributes to the discussion about the share per industrial sector to the total blue and grey water. The quantities per industrial sector and differences between industrial sectors can be seen for the first time. The method used in this study results in larger global blue and grey water footprint of the industry than other literature. The blue and grey water footprint is specified per country, industrial sector, and domestic water supply and, per year since 1960. The hydroelectricity division is according to this study responsible for a significant blue water footprint but is often not accounted for in other research. It can be concluded that this study used a more detailed analysis than before in quantifying the water footprint of different industrial sectors and the domestic water supply per country for a longer period and gives an insight in differences between industrial sectors, countries and years.