Page 357 - Wastewater Solids Incineration Systems

318 Wastewater Solids Incineration Systems

TABLE C.5 Factors that might be used to amortize capital costs.

Useful life 3.0% 3.5% 4.0% 4.5% 5.0% 5.5% 6.0%
5 0.218 0.221 0.225 0.228 0.231 0.234 0.237
10 0.117 0.120 0.123 0.126 0.130 0.133 0.136
15 0.084 0.087 0.090 0.093 0.096 0.100 0.103
20 0.067 0.070 0.074 0.077 0.080 0.084 0.087
25 0.057 0.061 0.064 0.067 0.071 0.075 0.078
30 0.051 0.054 0.058 0.061 0.065 0.069 0.073
40 0.043 0.047 0.051 0.054 0.058 0.062 0.066
50 0.039 0.043 0.047 0.051 0.055 0.059 0.063
Example: Installed cost $1,000,000 useful life 10 years interest rate 4.5%
$1,000,000 0.126 $126,000 annual amortized capital cost

Depending on the intended use of the incineration cost information, it may be
appropriate to include interest when amortizing capital costs. If a facility is using cost
information to track wastewater solids management costs or compare the cost of var-
ious technologies, it is acceptable to exclude interest costs and calculate amortized
capital costs as described above. However, if a facility is using cost analysis as part of
an annual budget presentation, it may be preferable to acknowledge that bond
interest is indeed part of the total financial cost of wastewater solids incinerators.
Table C.5 presents some factors that might be used to amortize capital costs in a
manner that includes interest expense.

5.0 REFERENCE

Dominak, R. P.; et al. (2005) Long-Term Residuals Management Plan for the Northeast
Ohio Regional Sewer District; Northeast Ohio Regional Sewer District: Cleve-
land, Ohio.

6.0 SUGGESTED READINGS
Harder, S.; Dominak, R. P. (2006) Biosolids Economics: A Case For Careful
Analysis. Proceedings of Water Environment Federation Residuals & Biosolids Man-
agement Conference [CD-ROM]; Cincinnati, Ohio, March; Water Environment
Federation: Alexandria, Virginia.