-------
o
o
o
o
82
a
UJ
N
I-
cc
o
5
5 MOD
150 MOD
10 20 30
CHLORINE CONTACT TIME (MINUTES)
40
50
FIGURE 6. AMORTIZED CAPITAL COST FOR CHLORINATION SYSTEMS VERSUS CHLORINE
CONTACT TIME
12
-------
MOD
56789
INTEREST RATES (%)
FIGURE 7. AMORTIZED CAPITAL COST FOR CHLORINATION SYSTEMS VERSUS INTEREST RATE
13
-------
j 3
<
O
o
O
o
V)
82
a.
<
o
o
IXI
N
CC
O
5
1-
5 MOD
150 MGD
2.0
2.2
2.4 2.6
CONSTRUCTION COST INDEX (100)
2.8
3.0
FIGURE 8. AMORTIZED CAPITAL COST FOR CHLORINATIOIM SYSTEMS VERSUS
CONSTRUCTION COST INDEX
14
-------
o
o
o
o
V)
82
_i
<
E
o
LU
N
F 1
oc
O
1 MGD
150 MGD
0 10 15 20 25 30
AMORTIZATION PERIOD (YEARS @ 7% INTEREST RATE)
FIGURE 9. AMORTIZED CAPITAL COST FOR CHLORINATIOIM SYSTEMS VERSUS
AMORTIZATION PERIOD
15
-------
< 2
0
o
o
o
tf>
o
o
<*
O
1-
2345
CHLORINE (MG/L)
FIGURE 10. O&M COST FOR CHLORIIMATIOIM SYSTEMS VERSUS CHLORINE DOSAGE
16
-------
~ 3
O
o
o
o
O 2
O
O
LU
H 1
cc
o
5
MOD
5 MOD
150 MGD
2 3
CHLORINE DOSAGE (MG/L)
FIGURE 11. AMORTIZED CAPITAL COSTS FOR CHLORIIMATIOIM SYSTEMS VERSUS
CHLORINE DOSAGE
17
-------
BJ
O
iJ
—t
ra
4-1
0
H
•a; g
MI
e
O
LO
rH
L3
O
•H
cfl
jj
•H
O
vO
!~H
O
O
O
d
o
^o
i-H
cx (
CO
0
rH
bO
S
0
0
rH
00
6
O
r-H
-a
GO
£
m
13
bo
S
rH
nj
4J
o
H
S
O
rH
rO
4-1
•H
a
CO
4-1
o
H
E
o
rH
4-1
•H
CX
ctf
CO
4-1
O
S
^3
O
rH
CO
•H
ttj
CJ
rH
4-1
O
H
E
l£
0
rH
cO
4-J
>H
CX
cd
CJ
e
o
4J
M
'-O
rH
o
o
o
d
ON
rH
CO
CM
O
o
o
o"
CO
CM
en
o
o
o
d
P-,
o
CF\
O
o
o
d
o
rH
c
•H
to
PQ
O
^O
\o
CO
-a-
o
m
CM
vD
O
O
cn
m
rH
CO
m
0
r-
O
i —
CM
m
m
CM
CM
*
v£>
u~l
CO
cn
r-
rH
CM
^
CM
0
rH
CM
rH
i— t
e
0)
cn
CO
a>
r^
CM
1— (
0
^O
CM
m
-3-
O
CO
CM
CM
CM
in
in
m
rH
CO
^.
CO
0
rH
CM
ro
CO
m
CO
CO
rH
^0
m
CM
CO
^
o
ro
^
CM
0
rH
CO
m
0
CM
4-1
CO
O
c_>
rH
CO
•U
O
H
18
-------
2 NaClO? + Cl —> 2 C10? + 2 Nad
(1)
(181) (71) (135) (117)
1.3 mg/1 0.5 mg/1 0.9 mg/1 0.8 mg/1
Therefore, the chlorine feeding system and contact basins were estimated for
a 0.5 mg/1 dosage of chlorine with the rest of the standardized values fixed
at the levels shown in Table 1. The cost of sodium chlorite was estimated
as follows:
NaC102 cost (c/1000 gal) = ($0.70/lb)(13.34 Ib/mil gal)
= 0.934C/1000 gal
The NaC10» cost was added to the cost of chlorine (0.5 mg/1) to yield the
cost of a 1 mg/1 dosage of C10?. These values are shown in Table 3 for 1, 5,
10, 100, and 150 mgd plants. Figure 12 shows the cost of chlorine dioxide
versus treatment plant capacity. All of the factors which influence the
cost of C10? disinfection with the exception of NaC102 cost, would be the
same as those shown in the section on chlorination.
Figure 13 illustrates sensitivity in 0 & M cost due to changes in the
cost of NaC102- Amortized Capital cost sensitivity would be estimated by
examining the effect of changing the Cl_ dosage.
As can be seen, chlorine dioxide is more expensive than chlorination but
has one advantage in that it can be generated with relative ease in a system
with an existing chlorine feeding system. The only additional cost for such
an operation would be to the incremental cost for sodium chlorite, although
there are other mechanisms for generating chlorine dioxide, such as by the
use of sodium chlorate, a process commonly used in the pulp and paper industry.
None of these alternative methods are considered here because all of these
systems have been built on a scale much too large for municipal water supply
usage.
COST OF OZONATION
Another disinfectant which will be considered is ozone, although ozona-
tion does not produce a disinfectant residual to be carried throughout the
distribution system. Further, the reaction of ozone with organic matter
occurring in water is not known. For purposes of this analysis, the design
parameters listed in Table 4 have been assumed as standardized and a sensi-
tivity evaluation of the cost of ozonation based on these parameters has been
made for 1, 5, 10, 100, and 150 mgd plants operating at 70 percent capacity.
As ozone can be produced from both air and oxygen, both systems are evaluated.
Cost of Ozone from Air
Figure 14 depicts the total unit cost for ozone generated by air versus
plant capacity. The total unit costs are separated into 0 & M and Amortized
Capital costs in Figure 15. The impact of the variables which affect 0 & M
19
-------
H
S3
I
\ 4-1
o.
ffl
o
o
I-J
o
20
-------
o
o
o
821
o
K-
o
o
< 1-
o
'1510 20 40 60 80 100 120
PLANT SIZE (MGD)
140
160
180
200
FIGURE 12. TOTAL UNIT COST FOR CHLORINE DIOXIDE VERSUS PLANT SIZE
21
-------
3.5
3.0
.1
.3 .4 .5 6 .7
SODIUM CHLORITE COST (S/LB)
.8
.9
FIGURE 13. O&M COST FOR CHLORINE DIOXIDE SYSTEM VERSUS COST OF
SODIUM CHLORITE
1.0
22
-------
TABLE 4. DESIGN PARAMETERS FOR OZONATION
Design Parameters (Variable)
Ozone Dose
Ozone Contact Time
Cost of Oxygen
Construction Cost Index
Wholesale Price Index
Direct Hourly Wage Rate
Amortization Interest Rate
Amortization Period
Electric Power Cost
Design Parameter (Fixed)
Capacity Factor
Level
1 mg/1
20 min
0.046 $/lb
256.7
178.1
5.19 $/hr
7 percent
20 yr
$0.01/KWH
70 percent
23
-------
J-\ 5 10
100
PLANT SIZE (MGD)
150
FIGURE 14. TOTAL UNIT COSTS FOR OZONATION (AIR) VERSUS PLANT SIZE
24
-------
o
o
o
o
CAPITAL COST
O&M COST
01 510
100
PLANT SIZE (MGD)
150
FIGURE 15. AMORTIZED CAPITAL AND O&M COSTS FOR OZONATIOIM (AIR)
VERSUS PLANT SIZE
25
-------
cost are shown in Figures 16 through 18. These variables are as follows:
direct hourly wage rate, wholesale price index, and cost of electric power in
kilowatt hours.
Figures 19 through 22 illustrate the sensitivity of capital costs to
the following variables: ozone contact time, construction cost index, and
interest rate and amortization period. Ozone dose, as can be seen from
Figures 23 and 24, affects both Amortized Capital and 0 & M costs.
Table 5 summarizes the costs for 1, 5, 10, 100, and 150 mgd plants based
on standardized levels of the design variables in Table 4.
Cost of Ozone from Oxygen
Ozone can also be generated by using oxygen. Figures 25 and 26 show
the total unit costs and the disaggregated costs (0 & M and Amortized Capital),
respectively, versus plant capacity. Figures 27 and 28 illustrate the sensi-
tivity of the cost of ozonation (0 & M and Amortized Capital costs) to the
cost of liquid oxygen.
Table 6 summarizes the costs of 1, 5, 10, 100, and 150 mgd plants using
the standardized variables in Table 4.
COST OF AERATION
Aeration is frequently practiced for the removal of hydrogen sulfide and
reduced materials, such as ferrous iron and manganous manganese. In the
laboratory, aeration or purging is used as an analytic procedure to remove
trihalomethanes from water and it might therefore be used successfully as a
treatment technique. Experimentation has shown, however, that at typical
air-to-water ratios used in water treatment for removal of taste- and odor-
causing compounds (1:1) little removal of chloroform takes place. For this
analysis it was therefore assumed that the air-to-water ratio of 30 cu ft
of air to 1 cu ft of water would provide adequate removal of trihalomethanes,
which is consistent with laboratory results for effective chloroform removal.
Table 7 contains the standardized variables which were examined in the cost
analysis.
Figure 29 is a typical capital cost curve for an aeration basis as a
function of throughput in thousands of cubic feet. Figures 30 and 31 are
0 & M Amortized Capital cost curves, respectively, for the diffused aeration
system based on thousands of standard cubic feet per minute of air. Table 8
contains the cost per thousand gallons for a 1, 5, 10, 100, and 150 mgd
plant based on the standardized cost assumptions shown in Table 7.
COST OF GRANULAR ACTIVATED CARBON
Granular activated carbon (GAC) is not a substitute for chlorine
disinfection, but is well suited for the removal of various types of dissolved
organic materials including chloroform and other trihalomethanes. Most but
not all dissolved organics can be adsorbed, which actually removes them from
solution. Fresh, granular carbon has the following advantages for water
26
-------
34567
DIRECT HOURLY WAGE RATE (S/HR)
10
FIGURE 16. O&M COSTS FOR OZONATION (AIR) VERSUS DIRECT HOURLY WAGE RATE
27
-------
o
o
o
o
tO
o
o
52-
cS
o
100 MGD
OU MUU
.4
1.2 1.6 2.0 2.4 2.8
WHOLESALE PRICE INDEX (100)
3.2
3.6
4.0
FIGURE 17. O&M COST FOR OZONATION (AIR) VERSUS WHOLESALE PRICE INDEX
28
-------
(3
O
O
O
1 MGD
100MGD
=^^^^^
150 MGD
.005 .010 .015 .020 .025 .030 .035
COST OF ELECTRIC POWER ($/KWH)
.040
.045
.050
FIGURE 18. O&IW COST FOR OZONATION (AIR) VERSUS ELECTRIC POWER COST
29
-------
0
o
§2
O
o
El
0
Ul
N
OC
O
s
WOO
MOD
150
MOD
10 20 30
OZONE CONTACT TIME (MINUTES)
40
50
FIGURE 19. AMORTIZED CAPITAL COSTS FOR OZONATION (AIR) VERSUS OZONE
CONTACT TIME
30
-------
o
o
o
o
o
o
_J
<
a
o
o 1
LU
N
I-
oc
o
2.0
5 MOD
150MGD
2.2
2.4 2.6 2.8
CONSTRUCTION COST INDEX (100)
3.0
FIGURE 20. AMORTIZED CAPITAL COST FOR OZOIMATION (AIR) VERSUS CONSTRUCTION
COST INDEX
31
-------
3.5
3.0
:2.5-
O
O
O
«2.0-
-------
20 25
AMORTIZATION PERIOD (YEARS)
FIGURE 22. AMORTIZED CAPITAL COST FOR OZONATION (AIR) VERSUS AMORTIZATION PERIOD
33
-------
o
o
o
O
O
I 2-
O
1 MGD
5 MGD
10 MGD
100 MGD
150 MGD
1.0
OZONE DOSE (MG/L)
FIGURE 23. O&M COST FOR OZONATION (AIR) VERSUS OZONE DOSE
34
-------
u
o
o
°2
V)
o
o
a
LU
N
I-
ac
O
5
MOD
5 MOD
150 MOD
.5
1.0
OZONE DOSE (MG/L)
1.5
FIGURE 24. AMORTIZED CAPITAL COST FOR OZOIMATIOW (AIR) VERSUS OZONE DOSE
35
-------
o
H
O
O
o
w
U
f->
U
ES
O
OO
a
o
o
H
^
'cO
•P
O
H
j-
O
rH
4-J
•rH
CX
fj
rH
TD
60
S
0
rH
•a
B
m
T3
60
e
^
O
H
j-
<-3
O
rH
crj
•rH
ifl
rH
4J
0
H
V-
1,5
CD
rH
•H
TJ
O
rH
O
EH
;s
•.a
o
rH
cO
U
•H
D-
cB
U
cfl
CU
<
*>
rO CO
rH 0
O O
O
in so
CO OJ
CN CM
m m
rH O
0 0
0
O CM
•
N CO 0) O
O fe -5 O
CO
rH
m
rH
CO
CO
0
rH
1 —
&
CM
so
CN
rH
rH
rH
CM
rH
^
CO
0
rH
CO
CO
rH
rH
~d"
CN
sD
CO
CT-
r4
<3
cu
3 cy
4-1 W
•H >,
O co
0
0
o
0
0
0
o
o
0
o
o
o
o
o
o
o
0
o
o
o
o
o
0
o
o
0
0
o
0
o
o
o
o
o
o
o
0
o
o
0
0
o
0
o
0
o
o
o
CO
H
QJ
bO
CO
0
•U
CO
CN
o
o
CO
^
CO
CN
m
rH
SO
rH
rH
CN
^d"
CM
CM
CM
SD
CN
rH
rH
CO
rH
rH
O
-d-
CO
SO
^
!— .
CO
so
CN
_!_,
cn
o
rH
n)
4J
O
H
36
-------
5 10
100
PLANT SIZE (MGD)
150
FIGURE 25. TOTAL UNIT COST OF OZONATION (OXYGEN) VERSUS PLANT SIZE
37
-------
7-,
O 6.
o
o
o
C/5
I-
co
o
o
OB
o
Q
Z 3
(J
Q
UJ
N
I-
cc
o
AMORTIZED CAPITAL COST
5 10
100
PLANT SIZE (MOD)
150
FIGURE 26. AMORTIZED CAPITAL AND O&M COSTS FOR OZONATION
(OXYGEN) VERSUS PLANT SIZE
38
-------
o
§4
3
O
5
«s
o
1MGD
5MGD
10 MOD
34567
LIQUID OXYGEN COST (C/LB)
10
FIGURE 27. O&M COST FOR OZONATION (OXYGEN) VERSUS LIQUID OXYGEN COST
39
-------
5'
o
o
CO
O 3
O
O
Q
LU
N
o
5
1MGD
5MGD
m > ^_10 MGD
K 100MGD
150 MGD
01 23456789 10
LIQUID OXYGEN COST (C/LB)
FIGURE 28. AMORTIZED CAPITAL COST FOR OZOIMATION (OXYGEN) VERSUS
LIQUID OXYGEN COST
40
-------
t
W
g
-------
TABLE 7. DESIGN PARAMETERS FOR AERATION
Design Parameters (Variable)
Air to Water Ratio
Contact Time
Construction Cost Index
Wholesale Price Index
Direct Hourly Wage Rate
Amortization Interest Rate
Amortization Period
Electric Power Cost
Level
30 cu ft: 1 cu ft
20 min
256.7
178.1
5.19 $/hr
7 percent
20 yr
$0.01/KWH
Design Parameter (Fixed)
Capacity Factor
70 percent
42
-------
10
7_
CO
cc
-j
o
Q
O
O
105-
z
o
o
10
10 100
AERATION BASIN VOLUME IN CD FT (1000)
1000
FIGURE 29. CONSTRUCTION COST FOR AN AERATION BASIN
VERSUS VOLUME OF BASIN
43
-------
10'
(fl 6
EC 10b
o
Q
O
O
Z
Z
10'
10
10 100
STANDARD CUBIC FEET PER WIN (x 1000)
1000
FIGURE 30. ANNUAL O&M COSTS FOR AIR SUPPLY VERSUS
STANDARD CUBIC FEET PER MINUTE THROUGHPUT
44
-------
CO
cc
10
o
Q
10
CO
O
O
O
CO
z
o
o
10 100
STANDARD CU FT PER WIN (1000)
1000
FIGURE 31 CONSTRUCTION COST FOR AIR SUPPLY VERSUS
STANDARD CUBIC FEET PER MINUTE THROUGHPUT
45
-------
46
-------
treatment:
a. Adsorption of trihalomethanes that have been formed by chlorina-
tion practiced prior to GAG treatment;
b. Adsorption of most trihalomethane precursors so that chlorination
can be practiced after treatment with GAG without forming signifi-
cant quantities of trihalomethanes;
c. Reduction of possibility of producing hitherto unknown organic
byproducts during disinfection by reducing the amount of organic
matter available for reaction with any disinfectant; and
d. Reduction in the general level of organics, thereby increasing
the likelihood of removal of raw water organic contaminants that
may be of concern now or in the future.
Treating water with activated carbon involves two major and separate
process operations: filtration and reactivation. The water comes in contact
with the carbon by passing through a structure filled wither with carbon
granules or with a carbon slurry. Impurities are removed from the water by
adsorption when sufficient time is provided for this process. The structure
can be either a water treatment filter shell, in which the filter media has
been replaced with GAG or an independent carbon filtration system. The
separate carbon filtration system usually consists of a number of columns
or basins used as contactors that are connected to a reactivation system.
The primary focus of this economic analysis will be on the use of GAG as a
replacement for existing media in the filter shell. The economics of a
separate contactor system will also be examined.
After a period of use, the carbon's adsorptive capacity is exhausted and
it must then be taken out of service and reactivated by combustion of the
organic adsorbate. Fresh carbon is routinely added to the system to replace
that lost during hydraulic transport and reactivation. These losses include
both attrition due to physical deterioration and burning during the reacti-
vation process.
The approach taken in this analysis is first to evaluate the use of GAG
with an on-site reactivation system assuming that the GAG will replace the
media in the filter shell. Various levels of key design parameters will be
established at standard levels with the intent of evaluating their effect on
sensitivity of the cost of GAG systems. The "standard" system will consist
as in the previous analysis of fixing a given set of design variables at
predetermined levels. Secondly, an analysis will be made for the replacement
of GAG in the filter shell but with off-site or regional reactivation.
Finally, an evaluation will be made of the cost of a separate GAG contactor
system with on-site reactivation.
47
-------
The Cost of GAG as Filter Media Replacement
As mentioned previously, it was assumed that GAG would replace sand in
existing filters, thereby eliminating the need to consider the cost of
separate GAC contactors. For purposes of this analysis, a water treatment
plant is assumed to consist of an integral number of 1 mgd filters. For
example, a 10 mgd water treatment system is assumed to consist of ten 1 mgd
filters each with the following dimensions: 18.5' x 18.5' x 2.5', yielding
a total volume of 865 cu ft per filter.
The standard values and the design parameters chosen for examination
are shown in Table 9. All analyses perform will be based on the effect of
changing the design variables around these standard values.
Before examining sensitivities, the impact of three basic factors must
be considered: economies of scale, load factor, and reactivation frequency.
Figure 32 depicts the economies of scale associated with plant size for GAC
systems of 1, 5, 10, 100, and 150 mgd capacity, assuming the design variables
are held at the levels shown in Table 9. The unit cost for a 1 mgd plant is
approximately 440/1000 gal while the unit cost of a 150 mgd plant is close
to 5.5C/1000 gal. The cost curve rises sharply between 10 and 5 mgd, jumping
from 120/1000 gal to 15.5C/1000 gal. Figure 33 shows 0 & M and Amortized
Capital costs versus plant capacity.
Figure 34 depicts the cost for a 100 mgd plant, operating at a 70 per-
cent capacity factor, with the period between reactivation varying between
0.5 and 18 months. At might be expected, lengthening the time between
reactivation reduces the unit cost from 7.50/1000 gal at 0.5 months to
1.60/1000 gal at 18 months.
Figure 35 shows the interaction between capacity factor and reactiva-
tion frequency for a 100 mgd plant, in which it is assumed that the product
of reactivation period and load factor is 1, and that as capacity factor
decreases, the period between reactivations increases. For example, when
capacity factor is 100 percent, the reactivation frequency is assumed to be
one month, and when the capacity factor is 50 percent the reactivation
frequency is assumed to be two months. It can be seen that increasing the
time between reactivation periods reduces unit costs; however, this reduced
cost is offset by a reduced load factor which increases the unit cost. The
net effect is an increased cost from 5.30/1000 gal (100 percent load factor
@ one reactivation per month) to 6.20/1000 gal (50 percent load factor @
one reactivation every two months).
Having established the impact of these three variables (load factor,
reactivation frequency, and economies of scale), it is possible to examine
the sensitivity of cost to changes in the design parameters in Table 9.
Some of these variables influence only Operating and Maintenance cost, some
only Amortized Capital cost, and some of these variables affect both 0 & M
and Amortized Capital cost. The first group of variables to be examined that
influence 0 & M cost are as follows: hourly wage rate ($/hr), carbon loss
48
-------
TABLE 9. DESIGN PARAMETERS FOR GRANULAR ACTIVATED CARBON
Design Parameters (Variable)
Carbon Cost
Carbon Loss per Reactivation Cycle
Fuel Cost
Electrical Power Cost
Construction Cost Index
Wholesale Price Index
Direct Hourly Wage Rate
Amortization Rate
Amortization Period
Level
0.38c/lb
10 percent
1.26 $/mil BTU
O.Olc/KWH
256.7
178.1
5.19 $/hr
7 percent
20 yr
Design Parameters (Fixed)
Contact Time
Hydraulic Loading Rate
Volume per Filter (1 mgd)
Capacity Factor
Reactivation Frequency
Loss in Adsorptive Capacity
During Reactivation
4.5 min
2 gal/min/sq ft
865 cu ft
70 percent
1.4 months
0
49
-------
70,
60-
O
o
o
°40-
030-
O
z
13
20-
01 510 20
40 60 80 100 120
PLANT SIZE (MGD)
140
160
180
200
FIGURE 32. TOTAL UNIT COST VERSUS PLANT SIZE
50
-------
35
< 30
O
25
W
O
00
o
Q
I 15
Q
LU
N
I5
01 510 20 40 60 80 1OO 120
PLANT SIZE (MGD)
140
160
180
200
FIGURE 33. AMORTIZED CAPITAL AND O&M COSTS VERSUS PLANT SIZE
51
-------
o
§
CO
O 3^
O
3
-J
2
4 6 8 10 12 14
CARBON REACTIVATION FREQUENCY (MONTHS)
16
18
20
FIGURE 34. TOTAL UNIT COST FOR A 100 MGD PLANT VERSUS TIME BETWEEN
REACTIVATIONS IN MONTHS
52
-------
o
o
o
(A
O
o
1.0 1.2 1.4 1.6 1.8 2.0
100% 70% 50%*
•CARBON REACTIVATION FREQUENCY (MONTHS)
2.2
2.4
2.6
2.8
3.0"
•CAPACITY FACTOR (%)
FIGURE 35. TOTAL UNIT COST FOR A 100 MGD PLANT VERSUS THE PRODUCT OF TIME
BETWEEN REACTIVATIONS IN MONTHS AND CAPACITY FACTOR
53
-------
per reactivation cycle, fuel cost, wholesale price index, and electrical
power cost. Figures 36 through 40 illustrate the impact which these variables
have on cost.
Figure 36 shows that changes in hourly wage rate have a greater impact
on the cost of small plants than on large plants. For example, it can be
seen that as the hourly rate increased from 5.19 $/hr to 7 $/hr, the 0 & M
cost for 1 mgd plant increases from slightly over 21C/1000 gal to slightly
less than 28c/1000 gal. The same wage rate increase in a 150 mgd plant
increases the 0 & M cost from approximately 4C/1000 gal to 4.50/1000 gal.
Figure 37 shows the changes in 0 & M costs which result from increases
or decreases in carbon loss per reactivation cycle. Figures 37 through 40
show that 0 & M cost is very sensitive to changes in carbon loss but is
somewhat less sensitive to changes in fuel cost, wholesale price index, and
electric power cost.
The group of variables; that influence Amortized Capital cost are as
follows: Construction Cost Index (CCI), amortization interest rate, and
amortization period in years. Figure 41 illustrates the variable impact
that CCI has on Amortized Capital cost in C/1000 gal. The impact is great
for small plants, but decreases for larger plants. Figure 42 illustrates
the effects of increasing or decreasing interest rate on Amortized Capital
cost. As with CCI, the effect of changing this parameter is greater for
smaller plants than for larger plants. Figure 43 shows the same effect for
changes in amortization period.
Several of the design parameters listed in Table 9 influence both
Amortized Capital and 0 & M cost. These parameters are as follows:
activated carbon cost, carbon reactivation frequency, and the interaction
of carbon reactivation frequency and load factor. Figures 44 and 45 illus-
trate the influence that the cost of activated carbon will have on both
Amortized Capital and 0 & M cost. Figures 46, 47, 48, and 49 show these
same impacts for carbon reactivation frequency and for the interaction of
carbon reactivation frequency and load factor.
To illustrate how the sensitivity analysis can be applied to the
standard values in order to study the impact of local conditions on costs,
the following example has been constructed. If it were assumed that all of
the standardized values were held at the levels shown in Table 9, with the
exception of activated carbon loss, it would be possible to estimate the
impact that changes in its value would have on the system cost. Examining
Figure 37, it can be seen that as compared to the standardized values when
activated carbon loss is 15 percent for a 100 mgd plant the percent change
in 0 & M cost is + 29.5 percent, but when it is at 5 percent, the change is
- 14.7 percent. The standardized values yield an Amortized Capital cost of
1.5C/1000 gal and an 0 & M cost of 4.5C/1000 gal. Therefore, as carbon loss
affects only 0 & M cost, the change in total cost would be as follows:
GAG system cost (15 percent) = 1.5 + [4.5 + 4.5 (.295)] (2)
= 7.3C/1000 gal (3)
54
-------
35
30
< 25
0
O
O
O
5 20
(A
O
O
5
oO
O
15
10
150 MOD
34567
DIRECT HOURLY WAGE RATE ($/HR)
10
FIGURE 36. O&M COST VERSUS DIRECT HOURLY WAGE RATE
55
-------
35
30
25
020
o
o
o
2.15
o
(J
5 10
o9
O
1MGD
MOD
! 50 MOD
.02 .04 .06 .08 .10 .12 .14 .16
CARBON LOSS PER REACTIVATION CYCLE (%)
.18
.20
FIGURE 37. O&M COST VERSUS CARBON LOSS PER REACTIVATION CYCLE
56
-------
35
30
25
1 MGD
-•-
< 20
O
O
O
O
V)
O
O
5
<*
10
5 MGD
10 MGD
100 MGD
150 MGD
•02 .04 .06 .08 .10 .12 .14 .16 .18 .20
FUEL COST ($/100,000 BTU)
FIGURE 38. O&M COST VERSUS FUEL COST
57
-------
35
30
25
o
o
o
o .
t-
V)
O 15
0
5
«0
O
10
I I I
| 5 MGD
10 MGD
100 MGD
150 MGD
.5 1.0 1.5 2.0 2.5 3.0 3:5
WHOLESALE PRICE INDEX (1000)
FIGURE 39. O&M COST VERSUS WHOLESALE PRICE INDEX
4.0
4.5
5.0
58
-------
35
30
25
1 MGD
o
o
o
15
O
O
5
08
O
10
5-
=t=
5 MGD
10MGD
100 MGD
150 MGD
0 .005 .010 .015 .020 .025 .030 .035 .040 .045 .050
ELECTRICAL POWER COST (S/KWH)
FIGURE 40. O&M COST VERSUS ELECTRICAL POWER COST
59
-------
1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5
SEWAGE TREATMENT PLANT CONSTRUCTION COST INDEX (1000)
FIGURE 41. AMORTIZED CAPITAL COST VERSUS CONSTRUCTION COST INDEX
5.0
60
-------
35
30
O
025
o
20
O
til
N 10
5 MOD
.01 .02 .03 .04 .05 .06 .07
AMORTIZATION INTEREST RATE (FRACTION)
.08
.09
.10
FIGURE 42. AMORTIZED CAPITAL COST VERSUS AMORTIZATION INTEREST RATE
61
-------
35
30
O
o
§25
o
_l
<
o
Q
UJ
N
1C
O
10
MGD
10 15 20 25 30 35
AMORTIZATION PERIOD (YEARS)
40
45
50
FIGURE 43. AMORTIZED CAPITAL COST VERSUS AMORTIZATION PERIOD
62
-------
35
30
25
o
o
o
15
V)
o
O 10
08
O
0 .1 .2 .3 .4 .5 .6
CARBON COST (S/LB)
FIGURE 44. O&M COST VERSUS CARBON COST
.8
.9
1.0
63
-------
35
30
O
O
O
O
£20
O
O
t 15
O.
O
Q
U!
N
I-
DC
O
10
1 MOD
.4 .5 .6
CARBON COST ($/LB)
.8
.9
1.0
FIGURE 45. AMORTIZED CAPITAL COST VERSUS CARBON COST
64
-------
35i
30
25
O
O 20
o
o
H 15
(/>
O
o
510
o
MGD
150 MGD
0 .5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
CARBON REACTIVATION FREQUENCY (MONTHS)
FIGURE 46. O&M COST VERSUS REACTIVATION FREQUENCY
4.5
5.0
65
-------
35
-30
<
O
o
o
O 25
(A
820
1.MGD.
<
a.
o
o
HI
N
O
2
<
15
10
5.MGD
1.0 1.5 2.0 2.5 3.0 3.5
CARBON REACTIVATION FREQUENCY (MONTHS)
4.0
4.5
5.0
FIGURE 47. AMORTIZED CAPITAL COST VERSUS REACTIVATION FREQUENCY
66
-------
35
30
25
O
O 20
O
O
H 15
tf)
O
U
310
O
5
5 MOD
100 MGD
150 MGD
2.2
2.4
2.6
1.0 1.2 1.4 1.6 1.8 2.0
100% 70% 50%
CARBON REACTIVATION FREQUENCY (MONTHS) CAPACITY FACTOR (%)
2.8
3.0
FIGURE 48. O&M COST VERSUS INTERACTION BETWEEN REACTIVATION FREQUENCY
AND CAPACITY FACTOR
67
-------
35,
10 MGD
• i —
100 MGD
-
150 MGD
1.0 1.2 1.4 1.6 1.8 2.0
100% 70% 50%
CARBON REACTIVATION FREQUENCY (MONTHS) CAPACITY FACTOR (%)
FIGURE 49. AMORTIZED CAPITAL COST VERSUS INTERACTION BETWEEN
REACTIVATION FREQUENCY AND CAPACITY FACTOR
68
-------
GAG system cost (5 percent) = 1.5 + [4.5 - 4.5 (.147)] (4)
= 5.3C/1000 gal (5)
Figure 50 illustrates the percent change in cost for 1, 5, 10, 100, and
150 mgd systems that results from various activated carbon losses.
In the above equations, Amortized Capital cost remains constant as
activated carbon loss affects only 0 & M cost. Some of the parameters, such
as amortization period, have a multiplicative effect, as will be illustrated
below. Assuming that amortization period, which affects only Amortized
Capital cost, is in one case 10 years (150.9 percent) and in another case
30 years (85.4 percent), yields the following when compared with the
standardized value of l.Sc/1000 gal:
GAG system cost (10 years) = (1.5)(1.509) + 4.5 (6)
= 7.5C/1000 gal (7)
GAG system cost (30 years) = (1.5)(0.854) + 4.5 (8)
= 5.8C/1000 gal (9)
Equations 6 through 9 illustrate how the multiplicative factor affects
Amortized Capital cost.
Table 10 contains the percentage change in 0 & M cost that results from
setting the level for each design parameter at 50 percent, and at 150 percent
(for a 100 mgd plant), of standard values. Table 11 contains the same
information for Amortized Capital cost (for a 100 mgd plant). It should be
noted that some of the parameters, such as carbon cost, affect both Amortized
Capital and 0 & M cost.
The net effect of setting the design value for each parameter at the
high and low values is shown in Table 12. Using the values shown in Table 12
the 0 & M and Amortized Capital costs are calculated as shown below for a
100 mgd plant.
Additive Modifications High
Amortized Capital Cost (c/1000 gal): 1.5 + 1.5 (0.664)
Sum 2.5
0 & M (C/1000 gal): 4.5 + 4.5 (0.675)
Sum 7.5
Low
1.5 - 1.5 (0.730)
0.4
4.5 - 4.5 (.576)
1.91
Using the above values the total cost can be calculated as follows:
69
-------
+30.0-
+20.0.
O
0 +10.0-
a.
z o.oo-
lil
u
z
u
5?
-10.0'
-20.0'
-30.0-
-40.
0 2 4 6 8 10 12 14 16 18 20
% CARBON LOSS
FIGURE 50. PERCENT CHANGE IN PLANT COST VERSUS CARBON LOSS
70
-------
TABLE 10. DESIGN PARAMETERS AFFECTING 0 & M COSTS (100 mgd)
Parameters Affecting 0 & M Costs - Additive
Carbon Loss per Reactivation Cycle (percent)
Carbon Cost (c/lb)
Fuel Cost ($/mil BTU)
Power Cost (c/KWH)
Direct Hourly Wage Rate ($/hr)
Wholesale Price Index
Values
15
10
5
54
38
19
1.89
1.26
0.63
1.5
1.0
1.5
7.78
5.19
2.60
267
178
89
Percent (
29.6
0
14.7
16.9
0
-22.0
4.0
0
-3.8
0.6
0
-0.6
15.9
0
-15.9
6.0
0
-5.0
Parameters Affecting 0 & M Costs - Multiplicative
Reactivation Frequency (weeks between) 3 145.9
6 100.0
9 72.1
Capacity Factor (percent) 50 105.2
70 100.0
100 92.4
71
-------
TABLE 11. DESIGN PARAMETERS AFFECTING AMORTIZED CAPITAL COSTS (100 mgd)
Parameters Affecting Amortized
Capital Cost - Additive
Carbon Cost (c/lb)
Values Percent Change
54 16.9
38 0
19 -22.0
Construction Cost Index
385
257
125
49.5
0
-51.0
Parameters Affecting Amortized
Capital Cost - Multiplicative
Amortization Period (yr)
Interest Rate (percent)
Reactivation Frequency (weeks between)
Capacity Factor (percent)
10
20
30
10.5
7
3.5
3
6
9
50
70
100
150.9
100.0
85.4
127.3
100.0
73.0
121.5
100.0
91.5
128.9
100.0
76.4
72
-------
TABLE 12. NET EFFECT FOR SETTING DESIGN PARAMETERS AT HIGH AND LOW
LEVELS (100 mgd)
Additive Factors for 0 & M
Loss per Reactivation
Carbon Cost
Fuel Cost
Power Cost
Hourly Wage Rate
Wholesale Price Index
High (percent) Low (percent)
29.5
16.9
4.0
0.6
15.9
0.6
-14.7
-22.0
- 3.8
- 0.6
-15.9
- 0.6
Sum
+67.5
-57.6
Additive Factors for
Amortized Capital Cost
Carbon Cost
Construction Cost Index
16.9
49.5
-22.0
-51.0
Sum
+66.4
-73.0
Multiplicative Factors for 0 & M
Reactivation Frequency
Hydraulic Load
1.459
1.052
0.721
0.924
Product
Multiplicative Factors for
Amortized Capital Cost
Amortization Period
Interest Rate
Reactivation Frequency
Hydraulic Load Factor
1.535
0.666
1.509
1.273
1.215
1.289
0.854
0.730
0.915
0.764
Product
3.008
0.436
73
-------
Multiplicative Modifications High Low
Amortized Capital (c/1000 gal) (2.5)(3.008) (0.4)(0.436)
Product 7.5 0.17
0 & M (c/1000 gal) (7.5)(1.535) (1.91)(0.666)
Product 11.5 1.27
Sum 19C/1000 gal 1.440/1000 gal
Adding the final results for Amortized Capital and 0 & M costs yields a
high value of 19C/1000 gal and a low value of 1.44C/1000 gal. These results
illustrate the extremes which might result from localized conditions.
As can be seen from Figures 32 and 33, unit costs associated with
small treatment systems are extremely high. The bulk of the Amortized
Capital costs are for on-site reactivation facilities, which suggests the
possibility that for small plants some alternative to on-site reactivation
should be explored. One possibility would be to dispose of exhausted
activated carbon and to purchase new carbon. The cost of disposal for a
plant operating at 70 percent: capacity factor, with a period between reactiva-
tion of 1.4 months, is shown below:
(865 cu ft)(No. of filters)(30 lb)(8.57 reactivations)(38c/lb)
Disposal cost = cu ft y_r
(flow in mgd)(365 days/yr)(0.70)
Disposal cost = 33-lc/lOOO gal
The above value can be compared to on-site reactivation costs for a 1, 5, 10,
100, and 150 mgd plant operating at 0.7 load factor with once-per-1.4 months
reactivation (Figure 32). It can be seen from Figure 51 that disposing of
exhausted carbon is actually cheaper than on-site reactivation for small
plants (2 mgd or less) although it is obviously more expensive for larger
plants.
Figure 51 suggests that another option that needs to be explored is
that of regional reactivation. Regional reactivation consists of transport-
ing the exhausted carbon to a central site where a reactivation furnace is
located. This approach, which is particularly appropriate for small plants,
will be explored in the following section.
Regional Reactivation
For the purposes of this analysis, three sets of regional reactivation
conditions will be examined:
1. Regional reactivation systems consisting of off-site reactivation plants
capable of processing carbon from the equivalent of 31001b/day,
74
-------
DISPOSED CARBON COST
1 5 10
100
PLANT SIZE (MGD)
150
FIGURE 51. TOTAL UNIT COSTS VERSUS PLANT SIZE
75
-------
6200 Ib/day, 15,500 Ib/day, 31,000 Ib/day, and 62,000 Ib/day reactiva-
tion facilities. These systems will be designated RP , RP9, RP~, RP/»
and RP,., respectively.
2. Costs for individual plants shipping to these systems will be examined,
based on the assumption that a number of plants are sharing these
reactivation systems simultaneously. For example, the cost in c/1000 gal
for a 1 mgd plant shipping carbon to a RP.. and RP?, and a 10 mgd plant
transporting carbon to a RP, and RP- system will be calculated assuming
that the various regional off-site reactivation systems are being used
to capacity.
By transporting carbon to a regional reactivation center a small plant
is able to take advantage of the economies of scale inherent in a larger
reactivation furnace, although there is a debit associated with the trans-
portation cost required to gel: the carbon to the site. The assumptions
regarding the operation of the plants are the same as those in Table 9 (for
example, 70 percent load factor and 1.4 months between reactivation). The
costs associated with the water treatment plant will be as follows: the
initial activated carbon purchase (twice the capacity of the treatment plant,
as one batch of carbon is being reactivated while the other is in place)
and the make-up carbon (loss assumed at 10 percent per replacement cycle due
to handling); transportation costs, which will be assumed as $ . 10/ton-mile,
and a proportionate share of the off-site reactivation costs which will
consist of furnace capital and operating costs, assuming a 10 percent loss
of activated carbon during the reactivation process. Table 13 contains the
costs associated with the initial carbon cost, and the carbon loss as well
as the equivalent carbon reactivation requirements per day in Ib/day for
each plant size. Figures 52 and 53 show the total construction and operating
costs for an off-site reactivation furnace based on Ib/day of reactivation.
It is assumed in this analysis that the Amortized Capital and 0 & M costs for
reactivation system are divided equally among the number of plants shipping
carbon to it. For example, if five 1 mgd plants are shipping to an RP
system, the cost will be higher than if ten 1 mgd plants are shipping
carbon to RP,., system.
Transportation costs are calculated as follows for a 1 mgd plant
shipping carbon to a reactivation plant for a 30-mile round trip:
Transport (lOC/ton-mile) (865 cu ft) (30 miles) (30 Ib/cu ft) C-^^) (8.57 react/yr)
Cost = -- - • -- --
(365 days)(l mgd) (0.70)
= .1310/1000 gal (30-mile round trip)
On a per-gal-mile basis, the cost is
C /gal-mile = (.131C/1000 gal) (30 mile)
= . 0044C/1000 gal-mile
76
-------
TABLE 13. CARBON COSTS AND REACTIVATION REQUIREMENTS FOR REGIONAL
REACTIVATION SYSTEMS
Plant Size
(mgd)
1
5
10
100
150
Initial Carbon
Requirements
(lb)
51,900
259,500
519,000
5,190,000
7,785,000
Annual Cost
($)
1,861.4
9,307.1
18,614.1
186,141.3
279,212.0
Make-up
Carbon
($)
7,254
35,319
69,835
672,321
1,001,758
Reactivation
Requirements
(Ib/day)
617.86
3,089.29
6,178.57
61,785.71
92,678.56
77
-------
3500n
3000i
2500-
O
O
O 2000-
CO
O
01500-
z
o
H
O
= 1000-
h-
co
z
o
0 5001
10000
30000 50000
REACTIVATION RATE (LB/DAY)
70000
90000
FIGURE 52, CONSTRUCTION COST FOR CARBON REACTIVATION SYSTEM VERSUS
REACTIVATION RATE
78
-------
1000000.
CO
o
0
5100000-
08
o
10000-1
100
1000 1000O
REACTIVATION RATE (LB/DAY)
FIGURE 53. O&IVI COST FOR CARBON REACTIVATION SYSTEM
VERSUS REACTIVATION RATE
79
-------
The Amortized Capital cost and annual 0 & M cost for the off-site
reactivation systems are shown in Table 14. These costs can be assigned
equally to the water treatment plants served. For example, RP.. can serve
five 1 mgd treatment plants and the total cost is divided by five, but for
RP,.,, which can serve 10 1 mgd plants, the total annual cost is divided by 10.
Table 15 contains the flow in mil gal/yr and the total allocated cost plus
the initial activated carbon and makeup costs for each plant reactivation
configuration. As can be seen from Table 15, the unit cost for a 1 mgd plant
sending carbon to a regional reactivation furnace serving five plants is
higher than for a 1 mgd plant sending carbon to a system serving 10 plants
due to economies of scale in the reactivation system. Transportation costs
must also be considered as in the following discussion.
Figure 54 shows the distance-related costs associated with the regional
reactivation system for 1 mgd plants sending carbon to a RP and RP
reactivation system, as compared to on-site reactivation system, and the
slope of the curve shows that carbon can be transported for many miles before
an on-site system becomes cost effective. Figures 55 and 56 show similar
conditions for 5 mgd plants and 10 mgd plants transporting to RP_ and RP ,
and RP, and RP systems, respectively. It can be seen that for a 10 mgd
plant it also is cost effective to transport spent carbon over relatively
long distances, however, the gap between on-site and transporting off-site
narrows at this level. Figure 57 shows the impact of variations in trans-
portation cost on the total cost of a 10 mgd plant transporting waste to
a RP, system.
An alternative to replacing carbon in the filter shell is to build
separate carbon contactors as ah integral part of the treatment system.
A discussion of this option is presented in the following section.
Separate Contactor System
In the discussion to this point the costs presented have been based on
the assumption that carbon would replace sand in a filter plant. Therefore,
no Amortized Capital and 0 & M costs associated with separate carbon con-
tactors have been included in the analysis. It is very likely that operating
in such a manner is inconvenient and inefficient, causing higher carbon
losses due to excessive handling. A contactor system may be tailored specif-
ically for a given treatment plant operation. The assumptions used for the
contactor system analysis are as follows (Table 16): two contactors connected
in series, a contact time of nine minutes and a corresponding recycle
frequency of one-per-2.8 months, bed depths of 20 ft, and a carbon loss of
5 percent per reactivation cycle. Figure 58 compares the costs for a separate
contactor system versus replacement of carbon as filter media.
Replacing sand by carbon represents a short-term possibility for water
treatment plants with low capital investment but high operating costs. A
separate contactor system represents a longer term and permenent solution
with higher capital investment requirements but with lower operating costs
as shown in Table 17. These capital investment requirements are discussed
in the following section.
80
-------
TABLE 14. AMORTIZED CAPITAL AND OPERATING COSTS FOR OFF-SITE REACTIVATION
SYSTEMS
Reactivation
System
RP1
RP2
RP3
T?"P
A
c.
Reactivation
Requirement
(Ib/day)
3,089.27
6,178.57
15,446.35
30,892.85
61,785.71
Construction
Cost
($)
700,000
820,000
1,350,000
1,630,000
2,200,000
Amortized
Capital Cost
($)*
66,080
77,408
127,440
153.872
207,600
Annual
0 & M Cos
($)
180,000
240,000
460,000
750,000
1,130,000
* 7 percent interest, 20-yr amortization period.
81
-------
TABLE 15. REACTIVATION SYSTEMS COST FOR AN INDIVIDUAL PLANT
Regional Reactivation
..-.
Regional
Reactivation
Configuration
1 - RP
1 - RP2
C __ "Dp
5 - RP4
10 - RP.
4
10 - RP5
Total No.
of
Plants
Flow per Plant
(mil gal/yr)
5 225
10 225
5
10
1277.5
1277.5
5 2555.0
10
2555.0
Total Annual
Cost
($)
56,470.00
38,995.00
162,114.10
135,013.10
269,321.0
222,217.1
Unit Cost
(0/1000 gal)
25.1
17.3
12.7
10.6
10.5
8.7
82
-------
70
60
~ 50
O
o
2 40
8 30
o
=> 20
t-
z
10
ON SITE REACTIVATION COST
I-RP-I
• •
I-RP2
0 20 40 60 80 100 120 140 160 180 200
DISTANCE TRAVELED (MILES)
FIGURE 54. COST OF TRANSPORTING CARBON FROM A 1 MGD PLANT TO REGIONAL
REACTIVATION SITE VERSUS DISTANCE IN MILES
83
-------
70
60
50
o
o
o
40
i-
V)
o
o
t 30
z
ID
o 20
ON SITE REACTIVATION
10'
5-RP3
5-RP4
0 20 40 60 80 100 120 140 160 180 200
DISTANCE TRAVELED (MILES)
FIGURE 55. COST OF TRANSPORTING CARBON FROM A 5 MGD PLANT TO REGIONAL
REACTIVATION SITE VERSUS DISTANCE
84
-------
70
60
<50
O
O
o
o
7^40
o
"30-1
H
Z
ID
<20-|
O
ON SITE REACTIVATION COST
10
10-RP4 10.Rp5'
0 20 40 60 80 100 120 140 160 180 200
DISTANCE TRAVELED (MILES)
FIGURE 56. COST OF TRANSPORTING CARBON FROM A 10 MGD PLANT TO REGIONAL
REACTIVATION SITE VERSUS DISTANCE IN MILES
85
-------
ON SITE REACTIVATION
40 60 80 1OO 120 140 160 180 200
FIGURE 57. THE SENSITIVITY OF REACTIVATION COSTS TO TRANSPORTATION
COST VARIATIONS
86
-------
TABLE 16. ASSUMPTIONS FOR SEPARATE CONTACTOR SYSTEMS
Item
Number of Contactors
Hydraulic Loading (gal/min/sq ft)
Diameter Contactors (ft)
Depth of Contactors (ft)
Vol. of Granular Activated Carbon
per Contactor (cu ft)
Apparent Contact Time (min)
Plant Capacity (mgd)
1
2
4
8
13
653.1
9
5
4
.87 5.
12
13
1469.5
9
10
8
42 5
12
13
1469.5
9
100
28
.42 5.
20
14
4396.0
9
150
42
57 5.57
20
14
4396.0
9
Reactivation Frequency (months)
at 70 percent Capacity 2.8 2.8 2.8 2.8 2.8
Activated Carbon Loss/
Reactivation (percent) 55555
87
-------
70-,
60
o
o
o
40
CO
o
o
30-
20
10
CONTACTOR SYSTEM
FILTER MEDIA REPLACEMENT
20 40 60 80 100 120
PLANT SIZE (MGD)
140
160
180
200
FIGURE 58. COMPARISON OF COSTS BETWEEN CONTACTOR SYSTEM AND MEDIA
REPLACEMENT VERSUS PLANT CAPACITY
88
-------
TABLE 17. AMORTIZED CAPITAL AND 0 & M COSTS FOR CONTACTOR VERSUS FILTER
MEDIA REPLACEMENT (c/1000 gal)
System ' 1 mgd
Media Replacement 19 . 5
Contactors
Media Replacement
Contactors
Media Replacement
Contactors
30.2
21.5
16.1
41.1
46.3
5 mgd 10 mgd
Amortized Capital
5 3.5
10.2 8.2
100 mgd 150 mgd
Costs
1.5 1.1
4.3 4.1
Operating and Maintenance Costs
10.5 8.2
7.3 5.4
Total Cost
15.5 11.7
17.5 13.6
4.5 4.0
2.4 2.2
6.0 5.1
7.3 6.3
89
-------
Capital Investment
All of the cost data presented to this point in the analysis have been
in terms of unit costs (including Amortized Capital and 0 & M costs). It is
important to present a different perspective by examining total investment
costs. Separate contactor systems, as can be seen from Table 17, are more
capital intensive then replacing the filter media by activated carbon. To
build these systems, utilities must raise considerable amounts of initial
capital. Table 18 summarizes for 1, 10, and 100 mgd plants the principal
and total payback costs required for both types of GAG systems.
A major part of the capital investment for an on-site reactivation
system is the furnace. Table 19 summarizes the estimated cost of these types
of furnaces.
TABLE 19
ESTIMATED CONSTRUCTION COST OF GRANULAR ACTIVATED CARBON REACTIVATION FURNACES
Furnace Type Capacity Estimated Total Cost
Multiple-Hearth 5,000 Ib/hr $4.2 million
Infrared* 5,000 Ib/hr $0.8 million
Rotary Kiln 5,000 Ib/hr See note
Fluidized Bed* 5,000 Ib/hr $1.2 million
* Because furnaces of this size have not been manufactured, these estimates
are very preliminary.
Note: Insufficient information is available to estimate a cost for this
type of furnace.
Labor Costs for GAG Systems
The previous analysis points to one salient fact regarding the use of
granular activated carbon. Unit costs for small plants reactivating on-site
may be prohibitively expensive. It is obvious that plants in the 1 mgd
design capacity should consider off-site reactivation in a regional facility.
All of the previous cost evaluations have been made for critical design
conditions, such as a once-per-1.4 month reactivation cycle and capacity
factors below 100 percent. These data have been computed for isolated
systems. In a total treatment complex, however, there may be opportunities
to share labor among several activities. For example, the laborers assigned
90
-------
00
rH
W
o
•u
«
e
o
o
r—{
4J
U
CO
C
o
O
4J
C
0)
nj £3
•H cu
T3 O
0) CO
JS} rH
cx
0)
*"O
00
e
o
rH
O
O
CO
4->
G
O
U
4-1
C
(1)
cO B
•H 0)
T3 O
0) tO
>*Tl 1
ff4 1 1
P.
0)
PS
t-i
o
-O
00
B
,_i
4-1
CJ
tfl
C
o
o
4-1
c
CU
co B
•H 0)
13 O
CU CO
P.
B
4J
M
r^ ro
O r*^
CN O\
CN r-{
rH CN
r*^ LO
-
-------
to groundskeeping or general labor might be utilized in the reactivation
activity. Such a joint use of labor might realize genuine savings, particu-
larly in a small plant. Table 20 displays the percentage of total costs
for plants with on-site reactivation which is made up of labor costs. It can
be seen that for small plants with on-site reactivation, labor costs account
for over 40 percent of the total cost.
SUMMARY AND CONCLUSIONS
It is obvious from the data presented in this report that chlorination
is the cheapest of all of the treatment technologies that might be used for
disinfection. Table 21 summarizes the values for a 1, 5, 10, 100, and 150
mgd plant for all of the treatment alternatives examined in this report.
As chlorination under certain conditions causes chloroform, a potential
carcinogen, in drinking water, planning and operating agencies must examine
alternatives to the chlorination process. These alternatives might take the
form of disinfection techniques other than chlorination, or of trihalomethane
removel techniques such as aeration, or of organic removal techniques such
as granular activated carbon. Hopefully, this report will assist in making
these evaluations.
92
-------
TABLE 20. LABOR COSTS FOR 1, 10, and 100 mgd GAG SYSTEMS REACTIVATING
ON-SITE (FILTER SHELL REPLACEMENT)
Plant
Capacity
5
10
100
Capacity
Factor
-7
• i
.7
.1
Total Cost
$/yr
199,915.97
302,103.2
2,098,677.0
Labor Cost
$/yr
91,385
124,724
421,756
Percent
Labor Cost
46
41
20
93
-------
^~\
rH
CO
60
0
O
O
1
r™*l
•o-
x-^
CO
w
H
CO
CO
o
o O
O rH O O ON VO
CM 1-^ vO 00 OO P-.
• • • • • •
rH tH rH rH CM rH
rH rH
vo o co in vo m
• • • • • •
rH CM CM CM --^ *— ' O T3
•H Q O Q)
4J C C S
CO 0) O O C »•!>-'
C G -H -H O cfl
•H -H 4J 4-1 -H rH C
\-i t-> cfl cfl 4J 3 O
o o e c co c 42
rH rH O O t-l Cfl >-l
,n ft N N a) t-i co
o u o o <; o u
CO
vO
r--
vO
v£>
•
CO
rH
m
•
r^
i-H
CO
•
vO
"*
ff^
13 en
Q) rl
4J O
Cfl 4J
> 0
•H CO
4J 4J
a c
-------
REFERENCES
1. Breidenbach, Andrew W., "Regulations: Reactions and Resolutions,"
Journal of the American Water Works Association, Vol. 68, No. 2,
February 1976, pp. 77-82.
2. Bureau of Labor Statistics, "Chapter 11. Wholesale Prices," reprint
from the BLS Handbook of Methods (BLS Bulletin 1711), U. S. Department
of Labor, pp. 97-111.
3. Eilers, Richard G., and Smith, Robert, "Executive Digital Computer
Program for Preliminary Design of Wastewater Treatment Systems,"
November 1970, NTIS-PB222765 (report NTIS-PB222764 (card deck).
4. Fair, Gordon Maskew, and Geyer, John Charles, "Elements of Water Supply
and Waste Water Disposal," John Wiley & Sons, Inc., New York, pp. 480-481.
5. Federal Water Pollution Control Administration, "Sewer and Sewage
Treatment Plant Construction Cost Index," U. S. Department of the
Interior, Washington, D. C. 20242.
6. Finerty, Joseph M. (Editor), Employment and Earnings, April 1976,
U. S. Department of Labor, Bureau of Labor Statistics, Vol. 22, No. 10.
7. Love, 0. T., et al., "Treatment for the Prevention or Removal of
Chlorinated Organics in Drinking Water," submitted for publication to
the Journal of the American Water Works Association.
8. Miltner, R. J., "The Effect of Chlorine Dioxide on Trihalomethane in
Drinking Water," Master of Science Thesis, University of Cincinnati,
1976.
9. Patterson, W. L., and Banker, R. F., "Estimating Costs and Manpower
Requirements for Conventional Wastewater Treatment Facilities for the
Environmental Protection Agency," Black and Veatch, Consulting Engineers,
Kansas City, Missouri, 1971.
10. Quarles, John R., Jr., "Impact of the Safe Drinking Water Act,"
Journal of the American Water Works Association, Vol. 68, No. 2,
February 1976, pp. 69-70.
11. Suindell-Dressler, "Process Design Manual for Carbon Adsorption,"
U. S. Environmental Protection Agency, Technology Transfer, October 1973.
95
-------
12. Symons, James M., "Interim Treatment Guide for the Control of Chloroform
and Other Trihalomethanes," June 1976, Water Supply Research Division,
Municipal Environmental Research Laboratory, Office of Research and
Development, Cincinnati, Ohio 45268, pp. 4-6.
13. Ibid, pp. 1-4.
14. Ibid, pp. 6-30.
96
-------
TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1 REPORT NO.
EPA-600/1-77-008
3 RECIPIENT'S ACCESSION-NO.
4 TITLE AND SUBTITLE
THE COST OF REMOVING CHLOROFORM AND OTHER TRIHALO-
METHANES FROM DRINKING WATER SUPPLIES
5. REPORT DATE
March 1977 (Issuing Date)
6. PERFORMING ORGANIZATION CODE
7 AUTHOR(S)
Robert M. Clark, Daniel L. Guttman, John L. Crawford,
John A. Machisko
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Same as below
10. PROGRAM ELEMENT NO.
1CC614
11. CONTRACT/GRANT NO.
12. SPONSORING AGENCY NAME AND ADDRESS
Municipal Environmental Research Laboratory—Cin.,OH
Office of Research and Development
U. S. Environmental Protection Agency
Cincinnati. Ohio 4S?(SR __^
13. TYPE OF REPORT AND PERIOD COVERED
In-house
14. SPONSORING AGENCY CODE
EPA/600/14
15. SUPPLEMENTARY NOTES
16. ABSTRACT
This research effort was conducted to provide an in-depth examination of the costs
associated with the use of activated carbon, ozonation, aeration, and chlorine
dioxide for removal of trihalomethanes.
The costs presented in this report are intended for the development of planning
estimates only and not for the preparation of bid documents or detailed cost esti-
mates. Exact capital and operating costs are highly variable from location to
location within the United States, even for plants of the same size and design.
These costs are presented in such a way as to enable the planner to make adjustments
to the reported costs when local information in available. Standardized levels for
a selected set of design parameters are assumed and sensitivity analysis is performed
for the majority of the parameters.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.IDENTIFIERS/OPEN ENDED TERMS
c. COS AT I Field/Group
Activated carbon treatment; Aeration;
Chlorination; Chloroform; Economic Analys:
Filtration; Operating Costs; Regeneration
(Engineering)
Chlorine dioxide;
Capital costs; Ozona-
tion; Trihalomethane
removal; Unit process
costs.
13 B
14 A
13. DISTRIBUTION STATEMENT
Release to public
19. SECURITY CLASS (This Report)
Unclassified
21. NO. OF PAGES
116
20. SECURITY CLASS (This page)
Unclassified
22. PRICE
EPA Form 2220-1 (9-73)
97
U S GOVERNMtNl rmnnnu UMI..I. I3//-/57-056/5488 Region No. 5-1
-------