WASTEWATER TREATMENT AND SOLIDS HANDLING
EPA-STP index value for December, 1983 of 370.
A-1. The costs included herein have been
This construction cost index value is a national
related to average wastewater flow so that they
average, and may be adjusted to a specific
may be readily usable for preliminary cost esti-
geographical location in accordance with AR
mating purposes without requiring a preliminary
A-5. It must be recognized that costs obtained
A-2. In order to relate all costs to a v e r a g e
from these costs curves are sufficiently accurate
wastewater flow, certain assumptions were made.
for preliminary, planning construction cost esti-
These assumptions are specifically listed on the
mation only. For preliminary cost comparisons,
applicable cost curves and are categorized as
additional costs should be included for items such
as engineering, legal, administration, and contin-
a. Influent waste and wastewater consider-
gency factors. More detailed cost estimates
ations. These include peak to average wastewater
should be prepared as outlined in TM 5-800-2.
flow ratios, influent BOD concentrations, average
quantities of sludge produced by specific pro-
A-6. Costs for lagoons, landfills, land treatment
cesses, average efficiencies of upstream treatment
and similar land-intensive systems are not pre-
sented due to the extremely wide variations in
b. Unit loading rates. These include total dy-
costs that can be experienced at a given location.
namic pumping head, hydraulic detention times,
cubic feed of air per pound of BOD, gallons of
include land cost and availability y, soil type and
wastewater per square foot per day, etc.
c. Additional units included in the treatment
A-7. Because of uncertainties regarding econo-
system package. For example, diffused air aera-
mies of scale, and in view of the lack of published
tion system costs are included with the total
date concerning costs for treatment plants with
activated sludge system costs, and carbon regen-
design flows less than 1.0 mgd, the curves are
eration costs are included in the total carbon
presented as broken lines between 0.1 mgd and
adsorption system cost.
1.0 mgd. In this range, the curves should be used
A-3. The peaking factors and design parame-
with discretion, realizing that the costs are based
ters used for cost development are taken f r o m
technical manuals, standard engineering text-
A-8. Figures A-1 through A-15 provide ap-
books and other references.
p r o x i m a t e costs of unit processes related to
A-4. Construction costs are related to a
system flow rate.