Biomethane Production as an Alternative Bioenergy Source from Codigesters Treating Municipal Sludge and Organic Fraction of Municipal Solid Wastes

Table 3

Transport fuel substitutes of the produced biomethane (PE = 100,000; X_PS = 61 g TS/PE·day; X_SS-OFMSW) = 50 g TS/PE·day) (adapted from Murphy et al. [21]).

Statement	Value	Unit
Replacement of diesel in heavy good vehicles (operating at 6 mpg on diesel 0.052 km/MJ)
Heavy good vehicle operating on CH4-enriched biogas, 90% efficiency of diesel	0.047	km/MJ
Potential travel distance powered by biogas: (2340 m^3/day × 330^(1) day/year × 35.9^(2)  MJ/m^3 × 0,047 km/MJ)	1,302,933	km/yr
Number of heavy good vehicles powered (50,000 km per year)	26	—
Diesel substituted of 1 m^3 enriched biogas: [2340 × 330 × 35.9 × (0.047/0.052)] ÷ (40.7^(3,4))	615,636 (~0.8)^(5)	L/yr (L/m^3)
Replacement of gasoline in cars (operating at 40 mpg on gasoline 0.439 km/MJ)
Car operating on CH4-enriched biogas, 90% efficiency of gasoline	0.396	km/MJ
Potential travel distance powered by biogas: (2340 m^3/day × 330^(1) day/year × 35.9^(2)  MJ/m^3 × 0.396 km/MJ)	10,977,904	km/yr
Number of cars powered (20,000 km per year)	549	—
Gasoline substituted of 1 m^3 enriched biogas: [2340 × 330 × 35.9 × (0.396/0.439)] ÷ (32.23^(3,4))	775,880 (~1.0)^(5)	L/yr (L/m^3)

⁽¹⁾Annual operation period of 330 days is assumed.
⁽²⁾Energy value of 1 m³ enriched biogas (95% CH₄) is 35.9 MJ.
⁽³⁾Energy value of oil 47.89 GJ/T; densities of diesel and gasoline are 850 and 673 kg/m³, respectively.
⁽⁴⁾Energy values of diesel and gasoline are 40.7 MJ/L (47.89 × 0.850) and 32.23 MJ/L (47.89 × 0.673), respectively.
⁽⁵⁾Since annual CH₄-enriched biogas production is 2340 m³/d × 330 d/yr ≅ 772,200 m³/yr, (615,636 ÷ 772,200) ≅ 0.8 L/m³ for diesel and (775,880 ÷ 772,200) ≅ 1.0 L/m³ for gasoline.