Table 4 Comparisons of operating costs in three scenarios with an annual plant capacity of 50,000 tons
Manufacturing costs | |||
|---|---|---|---|
Item | Annual cost (MM$/year) | ||
Variable operating costs-raw materials | Scenario #1 | Scenario #2 | Scenario #3 |
Gaseous feedstock | 24.71 | 30.32 | 17.61 |
Ammonia | 2.41 | 2.28 | 3.24 |
Flocculant | 12.75 | 12.84 | 13.05 |
Sludge disposal cost | 13.13 | 14.30 | 14.44 |
Makeup water | 0.18 | 0.15 | 0.20 |
Cooling tower chems | 0.06 | 0.06 | 0.06 |
Electricity | 0.00 | 2.34 | 0.00 |
Sum of variable operating cost of raw materials | 53.23 | 62.29 | 48.60 |
Variable operating costs-byproduct credits | |||
 AD sludge N credit | 1.13 | 0.96 | 1.27 |
 CO2 credit | 1.35 | 4.77 | 0.00 |
 Grid electricity | 0.82 | 0.00 | 1.44 |
 Sum of byproduct credits | 3.30 | 5.73 | 2.71 |
 Total variable operating costs (VOC) | 49.93 | 56.56 | 45.89 |
Fixed operating costs | |||
 Salaries | 2.33 | 2.33 | 2.33 |
 Labor burden | 1.40 | 1.40 | 1.40 |
 Facility maintenance | 4.00 | 4.50 | 3.58 |
 Property insurance and tax | 2.29 | 2.30 | 1.89 |
 Sum of fixed operating costs (FOC) | 10.02 | 10.53 | 9.20 |
 Total operating cost (VOC + FOC) | 59.95 | 67.09 | 55.09 |