Employing Input-Output Model to Assess …
177
high emission volume and huge damage to the water resource in China. The dilution
water for each pollutant is estimated as follows:
DW dilution = L/(C max − C nat )
where DW dilution is the direct dilution water(m
3 ); L is the discharge amount of
the studied water pollutant(g);C max is the maximum allowable concentration of the
studied water pollutant set by regulation (g/m
3 ); and C nat is the concentration of the
studied water pollutant in the natural water body (g/m
3 ). The pollutants of COD,
AN, PE, and VP are allowed to have the maximum concentrations of 20, 1, 0.05, and
0.005 mg/L, respectively, based on this standard.
LC W grey = max
LC W dilution,1 , LC W dilution,2 , LC W dilution,3 , LC W dilution,4
where LC W grey is the gray water footprint of the life cycle; LC W dilution is the life
cycle dilution water of each pollutant.
5.2 Results
First of all, it can be seen from Table 5 that comparing the five products, coal consumes
and withdraws the lowest amount of water, so end-user coal is superior to other fuels
in terms of saving water. Secondly, crude oil and natural gas use more water than
coal, and upgraded fuels, including coke and petroleum products, consume more
water due to energy loss during the upgrade process.
Second, we identified the pollutants that have the greatest impact on water quality
as shown in Fig. 1. We found that first, the water pollution of coke and petroleum
products extracted from coal and crude oil is always heavier than that of raw fuel
and produces a large amount of VP dilution water. Meanwhile, PE produces a large
amount of dilution water for all fossil fuels and becomes a decisive factor in the gray
water footprint of coal, crude oil, natural gas, and petroleum products. Another thing
worth noting is that although COD has the highest emissions in the fossil energy
industry, reaching 5–16 kg/TJ as shown in Fig. 1a, its allowable concentration is
Table 5 Water consumption, water withdrawal, wastewater discharge, and gray water footprint in
the life cycle production of fossil fuels (Unit: m 3 per TJ)
Items
Coal
Crude oil
Natural gas
Petroleum products
Coke
Water consumption
39
121
97
91
220
Water withdrawal
142
479
381
456
717
Wastewater discharge
123
358
284
385
498
Gray water footprint
1374
4780
1018
15084
6152
177
high emission volume and huge damage to the water resource in China. The dilution
water for each pollutant is estimated as follows:
DW dilution = L/(C max − C nat )
where DW dilution is the direct dilution water(m
3 ); L is the discharge amount of
the studied water pollutant(g);C max is the maximum allowable concentration of the
studied water pollutant set by regulation (g/m
3 ); and C nat is the concentration of the
studied water pollutant in the natural water body (g/m
3 ). The pollutants of COD,
AN, PE, and VP are allowed to have the maximum concentrations of 20, 1, 0.05, and
0.005 mg/L, respectively, based on this standard.
LC W grey = max
LC W dilution,1 , LC W dilution,2 , LC W dilution,3 , LC W dilution,4
where LC W grey is the gray water footprint of the life cycle; LC W dilution is the life
cycle dilution water of each pollutant.
5.2 Results
First of all, it can be seen from Table 5 that comparing the five products, coal consumes
and withdraws the lowest amount of water, so end-user coal is superior to other fuels
in terms of saving water. Secondly, crude oil and natural gas use more water than
coal, and upgraded fuels, including coke and petroleum products, consume more
water due to energy loss during the upgrade process.
Second, we identified the pollutants that have the greatest impact on water quality
as shown in Fig. 1. We found that first, the water pollution of coke and petroleum
products extracted from coal and crude oil is always heavier than that of raw fuel
and produces a large amount of VP dilution water. Meanwhile, PE produces a large
amount of dilution water for all fossil fuels and becomes a decisive factor in the gray
water footprint of coal, crude oil, natural gas, and petroleum products. Another thing
worth noting is that although COD has the highest emissions in the fossil energy
industry, reaching 5–16 kg/TJ as shown in Fig. 1a, its allowable concentration is
Table 5 Water consumption, water withdrawal, wastewater discharge, and gray water footprint in
the life cycle production of fossil fuels (Unit: m 3 per TJ)
Items
Coal
Crude oil
Natural gas
Petroleum products
Coke
Water consumption
39
121
97
91
220
Water withdrawal
142
479
381
456
717
Wastewater discharge
123
358
284
385
498
Gray water footprint
1374
4780
1018
15084
6152