Page 347 - Wastewater Solids Incineration Systems

308 Wastewater Solids Incineration Systems

Some of the questions frequently asked by WWTPs that practice incineration are

• How can I determine the actual cost to incinerate wastewater solids at my
plant?
• Which costs should be included in this analysis?
• How do my incineration costs compare to incineration costs at similar
WWTPs?

Appendix C provides a framework for WWTPs that practice incineration to accu-
rately determine their costs to incinerate.

1.0 COMPOSITION OF WASTEWATER SOLIDS
INCINERATION COSTS

Incineration costs consist of both amortized capital costs and operation and mainte-
nance (O&M) costs. The components of these two costs are as follows:
• Amortized capital cost
Initial construction costs and
Subsequent contractor-related replacement and repair costs.
• Operation and maintenance costs
Direct labor and benefits for WWTP incineration personnel;
Incineration-related electrical, natural gas, fuel oil, and scrubber water costs;
Maintenance work performed by WWTP personnel; and
Ash disposal costs.

2.0 STARTING POINT

Collecting accurate incineration-related wastewater solids management costs is a
daunting task that presents numerous challenges. The first step in this process is to
select a starting point in the solids processing train.
For the majority of WWTPs, the starting point can be assumed to be immediately
after dewatering because wastewater solids can either be incinerated, landfilled, land
applied (depending on quality), or placed in a surface disposal site.
Because incinerator ash is a byproduct of wastewater solids incineration, its reuse
and disposal cost is included in the overall incineration cost determination. The
starting point to determine the ash-related disposal cost is typically at the point the
ash leaves the incinerator.