Page 354 - Wastewater Solids Incineration Systems

Appendix C Determination of Wastewater Solids Incineration Related Costs 315

Because Westerly’s MHFs were originally constructed in 1978 and the significant
equipment had a service life of 20 years, the original construction costs are not
included in the 2004 cost determination. However, all costs associated with the 1994
to 1995 improvement program, with refractory replacement work—such as installa-
tion of two different sets of total hydrocarbon monitors and the purchase of ash
trucks—are included in the amortized capital cost calculation (see Table C.3 for
details). Amortized capital costs amounted to $251,697.

3.8 Incineration Cost Summary
Total incineration costs are listed below:

Total incineration costs (includes O&M and amortized capital costs) $1,154,658
Incineration O&M (does not include amortized capital costs) $902,961

3.9 Wastewater Solids Management Costs
Wastewater solids unit management costs are typically determined on an O&M wet
weight basis. However, these costs can also be determined on a total wet, total dry,
and O&M dry weight basis.

Wastewater solids incinerated in 2004: 16 441 wet tons (5426 dry tons)
Total unit disposal cost: $1,154,658/16 441 wet tons $70.23 per wet ton
$1,154,658/5426 dry tons $212.80 per dry ton
O&M unit disposal cost: $902,961/16 441 wet tons $54.92 per wet ton
$902,961/5426 dry tons $166.41 per wet ton
Note that 1 wet ton 0.907 metric tonne

4.0 BENCHMARKING—COMPARISON WITH
INCINERATION COSTS AT OTHER WASTEWATER
TREATMENT PLANTS
In a perfect world, comparing a WWTP’s total incineration related O&M costs
against a similar WWTP’s incineration-related O&M costs should reveal which is
more cost effectively incinerating its wastewater solids. However, because there are
several site-specific factors that can affect O&M costs, a direct WWTP-to-WWTP com-
parison simply is not realistic. For example,