-------
Table 6 shows the averages calculated for the 1-min "before" and "after" samples
I ,
{samples beginning with CR-X1-) collected during the three runs. A t-test was performed based on
the averages and standard deviations of the data. Differences between the "before" andinafter"
samples were examined at the 95% significance level. Suspended solids levels in the "before"
samples were relatively high, but were significantly reduced by the cartridge filter installed before
the resin tank. Iron and total chromium levels decreased significantly after ion exchange.; Iron
removal may be due either to removal of ferrous suspended particles on the cartridge filter or to
deposition of complexed iron on the resin. As in thfe cadmium tests, dissolved solids mass
decreased significantly, whereas conductivity (current-carrying capacity) remained relatively
constant after ion exchange. This is due to the heavier chromates in the rinsewater being replaced
with lighter hydroxide ions.
PRODUCT QUALITY ASSESSMENT . I
On the cadmium line, the full scale ion exchange system effectively reduced contami-
nants in the ion exchange discharge to levels comparable to those in the fresh tap water blank.
Dissolved solids and conductivity in the recycled rinsewater were slightly higher than in the field
{tap water) blank, but typical of those found in the rinse tanks during continuous production. A.
conductivity sensor monitored the conductivity in Rinse 2 tank. Fresh water could have been
introduced if conductivity became too high. Fresh water was also added periodically to make up
i
for dragout losses. The flow rate of 5 gal/min through the ion exchange unit (containing 94 Ibs of
resin with a total capacity of 5 Ibs of cadmium) appears sufficient to maintain contaminarits at
acceptable levels throughout the day under normal processing. A conductivity sensor in Rinse 2
tank monitored ion build-up in the rinsewater. The small volume of fresh make-up water was
added periodically primarily to compensate for dragout losses, not to lower conductivity.
In the three months following this testing, Torrington has not noticed any decline in the
quality of the parts processed through the cadmium rinse. For this testing, the rinsewater on the
chromium line was processed through a pilot unit « 1 gal/min). Contaminant levels were reduced
significantly by ion exchange, to levels slightly above those found in the tap water blank.!
Torrington plans to further reduce total chromium concentrations in the rinsewater by adding a
cation resin to remove any trivalent chrome in the rinsewater.
14
-------
Z
O
H
_l
^
ft
s
5
O
DC
O
DC
O
U.
HI
U
z
o
SIGNIFI
_1
U
p
, STATIS
(0
in
u
~
w =d
Q 0)
H E
w =i
w o>
I- E
E
0
c «
o o
0 1
3
"
_1
(J) '
u. 1
6 ^?
_o
1
s
C/3
E
0}
CO
CO
O)
0>
CO
ps
o
CD
*'
00
o
CO
00
en
.
P
0}
T3
cn
O)
oi
CO
in
IV
r_
CD
1
O
00
CD
CO
1
CO
in
CO
CN
3
to
^
Q
~ T3
CO
(0
O CO
y= o>
11
w o
o
c
significant
increase
V3
.j
significan
decrease
significant
decrease
s
1
~x
c
o
"o
tJ
£
CO
c>i
>*-
ID
U
O
ID
O
-a
o
ro
Q.
£
,9
-values are <
4-*
in
O
0
"o
0}
o
JO
o
'c.
^TO
is
CD
_
C
O
TJ
0)
ID
m
"to
15
-------
SECTION 3
POLLUTION PREVENTION POTENTIAL
The pollution prevention potential of the ion exchange technology was evaluated in terms
of waste volume reduction and pollutant reduction. Waste volume reduction addressed the gross
wastestream (e.g., Ibs of wastewater treatment sludge) and environmental resources expended
during disposal (e.g., landfill space). Pollutant reduction addressed the specific pollutants |in the
wastestream (e.g., chromium in the sludge). ', .
WASTE VOLUME REDUCTION
Table 7, which is based on Torrington's plant records, shows the fresh water flow rates
through the rinses before installing the ion exchange system (counter flow rinse only) and after
installing the ion exchange system. On the cadmium line, without ion exchange, Torringtoh was
maintaining 3 gal/min flow through Rinse 2, which overflowed into Rinse 1. An additional !5 gal/min
of fresh water was also run through Rinse 1. On the chromium line, without a full-scale ion
exchange system, Torrington ran a counter flow of 1 gal/min through Rinse 2, which overflowed
into Rinse 1. Rinse 1 also had an independent supply of 1 gal/min. These continuous flows
generated large amounts of wastewater that had to be treated on-site. With the ion exchange
system on the cadmium line, Torrington required only 50 gal/day (for 2 shifts, or 16 hr of operation)
to make up for dragout losses. A similar make-up amount is expected on the chromium line.
The wastewater generated each year by the rinsing operation is shown in Table 8. These
annual numbers are based on the flow rates in Table 7 and an annual operating time of 16' hr/day
(2 shifts), 5 days/week, and 50 weeks/yr. These numbers are typical of the influent volumes to
Torrington's on-site treatment plant. By using ion exchange, wastewater as a wastestream
requiring treatment is virtually eliminated.
The ion exchange operation generated small volumes of other wastestreams, namely,
spent filters and the regenerant. On the cadmium line, Torrington changed the filter cartridge once
in two months. On the chromium line, the cartridge change is expected to occur more frequently,
possibly once a month. ,
16
-------
TABLE 7. FRESH RINSEWATER FLOW RATES
Rinsewater
Cadmium System
Rinse 1
Rinse 2
Chromium System
Rinse 1
Rinse 2
Flow
Without
Ion Exchange"1'
5 gal/min
3 gal/min
1 gal/min
1 gal/min
Rate"1
With
Ion Exchange'0'
0
50 gal/day
0
50 gal/day
(a) With or without ion exchange, water from Rinse 2 overflows into
Rinse 1.
(b) Continuous flow 16 hr per day as per Torrington's normal operating
schedule.
(c) Intermittent flow; make-up water daily average measured by
Torrington.
On the cadmium line, the resin is scheduled to be regenerated about once a month when
the line is operating at full capacity. Each regeneration consists of 8 gal of 50% NaOH in 12 gal of
water, plus an additional 35 gal of water for rinsing the column (55 gal/regeneration, or 660 gal of
regenerant/yr). The regenerant will be subjected to electrolytic metal recovery (EMR) to recover
cadmium, and the rest will be sent to the on-site wastewater treatment plant.
TABLE 8. WASTE VOLUME REDUCTION
Without Ion Exchange With Ion Exchange
Amount Amount;
Waste Generated per Waste Generated per
Description year"" Description year""
Cadmium System
Wastewater 1,920,000 gal Wastewater 0 gal
Regenerant 660 gal
Filter cartridges 6
Chromium System
Wastewater . 480,000 gal Wastewater 0 gal
Regenerant 840 gal
Filter cartridges 12 ,
(a) Based on Table 7 values at 16 hr/day, 5 days/week, 50 weeks/yr.
(b) Based on pilot tests conducted by Torrington and resin capacity.
17
-------
The full-scale chromium ion exchange unit is expected to generate 70 gal of regenerarit
{20 gal of 50% NaOH in 50 gal of water) once a month, for a total of 840 gal of regenerant. The
regenerant will be passed through a cation exchange resin to convert sodium chromate to: chromic
acid.
POLLUTANT REDUCTION I
The pollutants of interest on the cadmium line are cadmium and cyanide. Without ion
exchange, the cadmium in the rinsewater is lost to wastewater. This wastewater is sent to the
I
on-site wastewater treatment plant. In a steel cyanide treatment tank, the wastewater is treated
using chlorine gas, sodium hypochlorite, calcium hypochlorite, and sodium hydroxide to oxidize the
cyanide. The wastewater then flows by gravity to another tank for neutralization. The cadmium
and other metals form hydroxides that settle in the clarifier as sludge. This sludge is hauled off site
for disposal. The treated water is discharged to the municipal sewer under a permit.
The average cadmium and cyanide concentrations in the wastewater when the cadmium
line is operating at full capacity are 4.31 and 17.60 mg/L, respectively (see Table 3, samp'le
CD-X30-B1). Without ion exchange, the annual generation of wastewater at full capacity :is
1,920,000 gal (Table 8). Therefore, approximately 69 Ibs of cadmium and 281 Ibs of cyaiiide are
lost annually. With ion exchange, most of the cadmium and cyanide are captured on the resin,
which is regenerated with NaOH. The regenerant is then subjected to EMR. At the time of the
on-site visit, the resin on the full-scale system was not yet exhausted (and had not been regener-
i
ated) due to reduced operation on the cadmium line at Torrington during that period. HoWever,
Torrington later regenerated the resin and demonstrated good recovery of cadmium by ElvjR on the
cathode (see Appendix A). During the EMR operation, some of the cyanide also decomposed. The
cathode (with the plated cadmium) in the EMR operation was then transferred to the cadmium
plating tank, where it functions as a cadmium anode. The rest of the regenerant was then sent to
the wastewater treatment plant. !
On the chromium line, without ion exchange, the rinse wastewater is sent to a fiberglass
tank, where it is mixed with sodium metabisulfite and sulfuric acid to reduce the hexavalent
chrome to trivalent chrome. The wastewater is then sent to another tank for neutralization. Here
!
the trivalent chrome forms a hydroxide that settles in the clarifier as sludge. The sludge is hauled
offsite for disposal and the treated water is discharged to the municipal sewer under a permit.
The average chromium concentration in the rinse wastewater when the chromium line is
operating at full capacity is 19.9 mg/L (Table 5, sample CR-X2-B1). Without ion exchange,
18
-------
480,000 gal of wastewater is generated^ peryear at full capacity {Table 8). Therefore,
approximately 80 Ibs of chromium is lost annually. WitrTion exchange, most of the chromium is
captured on the resin, which is regenerated with NaOH. The regenerant is then passed through a
cation exchange resin to convert sodium chromate to chromic acid. When this recovery was
performed during the pilot unit testing, the final regenerant liquid still showed a PH of 13.08.
Other parameters measured in the final regenerant were total chromium (14.6 mg/L), iron
(0.28 mg/L), dissolved solids (14,111 mg/L), conductivity (68,800,/mhos/cm), suspended solids
(2 mg/L), and sodium (7,010 mg/L). This indicates that sodium chromate had not been converted
to chromic acid, in which case the pH would have been much lower. This may be due to the fact
that (a) an excess of NaOH was used to regenerate the resin and/or (b) there was insufficient resin
to exchange all the sodium in the regenerant. Further testing is required to determine the feasibility
of the chromic acid recovery process.
POLLUTION PREVENTION POTENTIAL ASSESSMENT
By using ion exchange, large volumes of water are prevented from going to waste. This
water (an important resource) can be reused as a rinse on the cadmium and chromium lines. Virtu-
ally eliminating the wastewater stream also eliminates the hazardous sludge (containing cadmium or
chromium) that must be handled, transported, and disposed. Cadmium and chromium are hazard-
ous chemicals on EPA's Toxics Release Inventory. Both metals are also on the list of 17 priority pol-
lutants targeted in the EPA Administrator's 33/50 Program for 50% reduction in releases by 1995.
With ion exchange, small volumes of regenerant and a few spent filter cartridges are
generated that eventually have to be treated or disposed. The quantities of regenerant and filters
are, however, much smaller than the volumes of wastewater and sludge generated when ion
exchange is not used.
On the cadmium line, most of the cadmium that deposits on the resin can be recovered
and reused in the plating bath. Some of the cyanide on the resin is destroyed during cadmium
recovery (EMR) and the rest is destroyed in the on-site treatment plant. Therefore, cyanide is not a
recoverable resource.
On the chromium line, further testing is necessary to determine the feasibility of recover-
ing chromic acid for reuse in the plating bath.
19
-------
SECTION 4 !
ECONOMIC EVALUATION !
The economic evaluation involves a comparison of the costs of the ion exchange
operation versus the former practice (counterflow rinse). !
MAJOR OPERATING COSTS
Both cadmium and chromium lines are assumed to operate at full capacity for 16 hr/day,
5 days/week, and 50 weeks per year. Based on Torrington's plant records. Table 9 summarizes
the major annual operating costs for the cadmium rinsewater line with and without ion exchange.
Without ion exchange, the operating costs involved are for fresh water usage and wastewater
treatment. Fresh water (city supply) at Torrington costs $0.70 per 1000 gal. The annual usage of
water is 1,920,000 gal (Table 8). Most of this water ends up as wastewater. Wastewater
treatment costs for the cadmium line were based on an average cost of $22 per 1000 gal, of
wastewater, which includes cost of treatment chemicals, sludge disposal, municipal sewer
discharge fee, and treatment plant labor (see Appendix B). ;
With ion exchange, the operating costs in Table 9 were based on the following:
« Fresh water requirement of 50 gal/day (make up) at $0.70/1000 gal.
Energy costs were based on continuous operation of the ion exchange
0.5 hp circulation pump over a year and an EMR consumption of 6 kW hr
for each regeneration (12 regenerations per year); electricity costs
$0.075/kW-hr at Torrington. |
Labor cost was based on 0.5 hr of operator involvement per day during
normal operation, plus 4 hr operator time during each regeneration
(12 regenerations per year). The average labor rate for the system
operators is $7/hr.
Routine maintenance costs were based on replacement of the filter \
cartridge ($5 each, six times per year), replacement of EMR anode plates \
($30 each, one per year) and EMR cathode plates ($30 each, 12 per year),
and maintenance labor of 24 hr/yr at $7/hr). ;
20
-------
TABLE 9. OPERATING COSTS COMPARISO^ FOR CADMIUM SYSTEM
Item
Without Ion Exchange
Freshwater
Wastewater treatment
With Ion Exchange
Freshwater
Chemicals (50% NaOH)
Energy
Labor
Routine maintenance
- filter cartridges
- EMR anode plates
- EMR cathode plates
- labor
Waste Disposal
- regenerant
- filters
Amount
used
per year
1 ,920,000 gal
1,920,000 gal
12,500 gal
96 gal
1 564 kW hr
173 hr
6
1
12
24 hr
660 gal
6
Unit
cost
$ 0.70/1 000 gal
$ 22/1 000 gal
Total
$0.70/1 000 gal
$1.50/gal
$0.075/kW hr
$7/hr
$5
$30
$30
$7/hr
$22/1 000 gal
$400/36 units
Total
Total Annual
Cost
$ 1,344
$42,240
$43,584
$9
$144
$117
$1,211
$30
$30
$360
$168
$15
$67
$2,151
Waste disposal costs due to ion exchange were based on regenerant
disposal (660 gal/yr by on-site wastewater treatment at $22/1000 gal) and
disposal of spent filter cartridges (6 per year, off-site disposal at $400 per
36 filters).
As Table 9 depicts, operating costs for ion exchange recovery are much lower than those
for counter flow rinse alone. The main cost saving is the reduction in wastewater treatment costs.
In addition to operating cost savings, the recovered cadmium has value because it is reused in the
plating bath as a cadmium anode. The cost of cadmium anodes is approximately $15/Ib. For the
69 Ibs/yr of cadmium that is deposited on the ion exchange resin, the resulting value recovered is
approximately $1,036/yr.
Based on Torrington's plant records. Table 10 summarizes the major operating costs for
the chromium rinsewater line with and without ion exchange. Without ion exchange, the operating
costs involved are for fresh water usage and wastewater treatment. Fresh water (city supply) at
Torrington costs $0.70 per 1000 gal. The annual water usage is 720,000 gal (Table 8). Most of
this water ends up as wastewater. Wastewater treatment costs for the cadmium line were based
21
-------
TABLE 10. OPERATING COSTS COMPARISON FOR CHROMIUM SYSTEM
Item
Amount
used
per year
Unit
cost
Total Annual
Cost
Without Ion Exchange
Freshwater 480,000 gal
Wastewater treatment 480,000 gal
With Ion Exchange
Freshwater 12,500 gal
Chemicals (50% NaOH) 240 gal
Energy 1492 kW hr
Labor 149hr
Routine maintenance
- filters 12
- labor 24
Waste Disposal
- regenerant 840 gal
- filters 6
$ 0.70/1000 gal
$ 15/1000 gal
Total
$0.70/1000 gal
$1.50/gal
0.075/kW hr
$7/hr
$5
$7/hr
$15/1000 gal
$400/36 units
Total
$ 336
$7,200
$7,5i36
:$9
$112
$1,043
$60
$168
$1,832
on an average cost of $15 per 1000 gal of wastewater, which includes cost of treatment
chemicals, sludge disposal, municipal sewer discharge fee, and treatment plant labor (see
Appendix B). '
With ion exchange, the operating costs in Table 9 were based on the following: i
Fresh water requirement of 50 gal/day (make up) at $0.70/1000 gal. >
i
» Energy costs were based on continuous operation of the ion exchange j
0.5 hp circulation pump over a year; electricity costs $0.075/kW hr at '
Torrington. '. ':
i
Labor cost was based on 0.5 hr of operator involvement per day during
normal operation, plus 2 hr operator time during each regeneration
(12 regenerations per year). The average labor rate for the system i
operators is $7/hr. '
Routine maintenance costs were base'd on replacement of the filter cartridge
($5 each, six times per year) and maintenance labor of 24 hr/yr at $7/hr).
Waste disposal costs due to ion exchange were based on regenerant ;
disposal (840 gal/yr by on-site wastewater treatment at $15/1000 gal) and
disposal of spent filter cartridges (6 per year, off-site disposal at $400 per
36 filters).
22
-------
As shown in Table 10, operating costs for ion exchange recovery are much lower than
those for counter current rinse alone. The main cost saving is the reduction in wastewater
treatment costs. In addition to operating cost savings, the chromium deposited on the ion
exchange resin has value if it can be successfully recovered as chromic acid. The cost of chromic
acid is approximately $2.50/|b. Approximately 80 Ibs/yr of chromium metal is deposited on the ion
exchange resin. This corresponds to about 154 Ibs of chromic acid (CrO3). However, further
testing is required to establish the feasibility of chromic acid recovery from the chromium in the
regenerant.
CAPITAL COSTS
According to Torrington's plant records, the purchase price of the cadmium ion exchange
system was $8,100 (including ion exchange resin column, pumps, and collection tanks). The EMR
equipment price was $4,125 (including rectifier, pump, anodes, cathodes, and solution tank).
Installation cost at Torrington, including materials (piping, etc.) and labor, was approximately
$3,500. To approximate the cost of in-house pilot testing used to determine specifications for the
individual plant, $5,000 was added to this figure.
The purchase price of the chromium ion exchange system (based on vendor information)
is estimated to be $8,200 (including ion exchange resin column, pumps, and tanks). Installation
cost at Torrington is expected to be $3,500, including materials (piping, etc.) and labor. The
approximate cost of $5,000 for in-house testing is also added for this unit.
RETURN ON INVESTMENT
A rough estimate of the payback period can be obtained by the following formula:
Payback, yrs = . capital cost
operating cost savings + recovery value
For the cadmium ion exchange system, total capital costs are $20,725 (purchase price,
pilot testing, and installation), savings in annual operating costs are $41,433 (difference in total
operating costs between "with" and "without" ion exchange as per Table 9), and the recycled
cadmium value is $1,036. This gives a payback period of less than a year.
23
-------
For the chromium system, the estimated total capital costs are $16,700 (purchase price,
pilot testing and installation) and savings in operating costs are $5,704 (see Table 10). Because
chromic acid recovery from the regenerant is yet to be established, no recycled chromium value is
assumed. This results in a payback period of approximately 3 years.
The difference in payback periods between the ion exchange systems on the cadmium
and chromium lines is primarily because, under former practice (without ion exchange), the water
flow rate through the cadmium rinse tanks was much higher than in the chromium tanks. In
addition, the unit cost of wastewater treatment for the cadmium rinsewater was also higher than
that for chromium rinsewater. Because the operating costs for both cadmium and chromium ion
exchange systems are similar, there is a greater annual operating cost savings for the cadpiium
line. . !
The above payback period estimation is a 'simple calculation that does not take into
account such factors as cost of capital, inflation, etc. A more complete economic analysis is
presented in Appendix C (cadmium line) and Appendix D (chromium line). The worksheets provided
in the Facility Pollution Prevention Guide (U.S. EPA, 1992) were used for the calculations. Based
on a detailed economic analysis, the cadmium ion exchange system still shows a payback period of
less than 1 year. On the chromium line, a positive return on investment (ROD occurs in year five
(break-even point on the original capital investment). If a cost of capital of 15% is to be recovered,
however, the payback period is 8 yrs (ROI > 15%). :
24
-------
SECTION 5
QUALITY ASSURANCE
Quality Assurance Project Plans (QAPP) were prepared and approved by EPA before
testing began (Battelle, 1992a and b). This QAPP contains a detailed design for conducting this
study. The experimental design, field testing procedures, and laboratory analytical procedures are
covered. The QA objectives outlined in this QAPP are discussed below.
ON-SITE TESTING
On-site testing for the cadmium ion exchange system was conducted as planned, except
for the EMR test. Because the full scale system was installed a few days before on-site testing and
because the workload on Torrington's cadmium line was somewhat reduced, the resin had not
reached exhaustion and could not be regenerated during the on-site visit. However, Torrington
subsequently performed the regeneration of the resin and EMR to demonstrate the recovery of
cadmium in a reusable form. The resulting data are presented in Appendix A.
On-site testing for the chromium system was affected by the fact that a full-scale system
was not installed in time for testing. A pilot system that had enough capacity to run for an hour
was tested instead. Samples from the two rinse tanks that were planned to be collected in the
morning, afternoon, and evening to monitor rinsewater quality over the entire day could not be
collected. In the pilot unit, the regenerant could not be isolated between the primary'ion (anion)
exchange column and the auxiliary cation exchange column. Hence, a regenerant sample before
cation exchange could not be obtained. Only the final regenerant sample after cation exchange
was obtained. Figures 1 and 2 in Section 1 have been slightly modified (from those in the QAPP)
to eliminate the collection tank from the loop. In both cases, the regenerant goes directly to the
next step.
All other samples were collected as planned. The 2-hr continuous composite was
changed to a 30-min composite because of the reduced scale of operation, and because the racks
were being processed continuously rather than every 2 hr.
25
-------
LABORATORY ANALYSIS ;
Appendix E lists the standard methods used for analyzing each parameter. Analysis was
performed as planned on the cadmium and chromium samples collected. Holding time for! pH,
which had been set at 2 days, was exceeded by a day; however, this is not expected to have any
significant effect on the results because the samples were on ice and pH of rinsewater is fairly
stable. __,., i .
The precision and accuracy of the analyses are listed in Tables 11 and 12, respectively.
The regular sample and duplicate values listed in this table are based on pre-made dilutionis of the
original samples prepared by the analytical laboratory. Table 11 also gives the detection limits for
each parameter. All laboratory blanks had very low or undetected values. Precision of the total
dissolved solids analysis for the chromium system was slightly out of range (>25%). However,
there was a wide enough difference (statistically) between the dissolved solids results for the
"before" and "after" samples for this to be of any consequence. Sodium in the field blank
(CR-FB-1) was measured at 2.63 mg/L. Sodium analysis was intended to be indicative of
conversion of sodium chromate to chromic acid. However, because a regenerant sample bould not
be isolated before cation exchange, only the final regenerant was analyzed. The resulting sodium
TABLE 11. PRECISION DATA FOR RINSEWATER CHARACTERIZATION
Parameter
Cadmium Study
Cadmium
Cyanide
Iron
PH
Conductivity
TDS
TSS
Chromium Study
Chromium
Sodium
Iron
pH
Conductivity
TDS
TSS
Sample
No.
CD-R1-B2
CD-R1-B3
CD-R1-B3
CR-X1-B3
CR-X1-B3
CR-X1-B3
CR-X1-B3
CR-X1-B2
CR-CX-A1
CR-X1-B2
CR-X1-B2
CR-X1-B2
CR-X1-B2
CR-X1-B2
Regular
Sample""
941
247
410
11.48
936
205
<1
728
28.04
855
4.67
104
99
8
Duplicate'"1
982
256 :
408
11.48
940 ;
202
<1
733
32.76
852
4.70
104
98
6
Precision
(% RPD)
4.3
3.6
-0.5
0.0
0.4
- 1 .5
0.0
0.7
1 5.5
-0.4
0.6
0.0
-1.0
-28.6
Detection Limit
10ug/L
10ug/L
50 ug/L
0.01 S.U.
1 .00 //mhos/cm
1 mg/L
0.1 mg/L
20/jg/L
0.5 mg/L
50 //g/L
0.01 S.U.
1 .00 //mhos/cm
1 mg/L
0.1 mg/L
i
Laboratory
Blanks'31
,
<10
<10
<;50
5.35
2.45
<1
4
i
<20
<0.5
<50
5.35
! 2.45
<1
4
(a) Units of measurement for each parameter are given in the "Detection Limit" column.
26
-------
TABLE 12. ACCURACY DATA FOR RINSEWATER CHARACTERIZATION
Parameter
Cadmium Study
Cadmium
Cyanide
Iron
Chromium Study
Chromium
Sodium
Iron
Sample No.
CD-R1-B2
CD-R1-B3
CD-R1-B3
CR-X1-B2
CX-CX-A1
CR-X1-B2
Regular
, Sample
(ug/L)
941
109.8
410
728
28,040
855
Matrix
Spike Level
(ug/L)
1 ,000
300
1,000
1,000
5,000
1,000
Matrix Spike
Measured
(ug/L)
1,953
422.3
1,317
1,693
32,760
1,972
Accuracy %
Recovery
101
104
91
97
94
112
concentration is discussed in Section 3 under the heading "Pollutant Reduction." Based on the above
discussion, completeness percentages are listed in Appendix F.
LIMITATIONS AND QUALIFICATIONS
Based on the above QA data, the results of the on-site and laboratory testing on the cadmium
line can be considered a valid basis for drawing conclusions about product quality, pollution prevention
potential, and economics. Economic and waste reduction information was obtained from Torrington's
plant records over the past year.
On the chromium line, water quality in the rinse tanks could not be monitored over a period
of one day of operation because of the small resin size. However, the contaminant removal in the
chromium rinsewater samples actually collected follows the same pattern as in the cadmium samples.
Given the chromium removal in the "after" samples exiting the ion exchange, it is expected that an
appropriately sized ion exchange system would maintain good water quality in the rinse tanks. The
unresolved issue in the pollution prevention evaluation on the chromium system is the feasibility of
recovering chromic acid that can be returned to the plating bath. The on-site tests were unable to recover
the chromium as chromic acid. More tests need to be performed to prevent chromium loss through the
regenerant. Economically however, there is sufficient data to show that, even without the final recovery
of chromium as chromic acid, the system results in cost savings for the user.
27
-------
SECTION 6 j
l
CONCLUSIONS AND DISCUSSION '
The evaluation showed that rinsewater on both the cadmium and chromium lines at
Torrington Company can be reused after subjecting the water to filtration and ion exchange to
remove impurities. Large volumes of water are thus prevented from going to waste. Disposal of
large amounts of hazardous metals sludge in the environment is also prevented. The sidestreams
from ion exchange are negligible compared to the wastewater and sludge wastestreams generated
in the absence of ion exchange. The ion exchange resin can be regenerated with sodium 'hydrox-
ide. On the cadmium line, the regenerant can be subjected to EMR and the cadmium recovered on
the cathode. This electrode, with the deposited cadmium, is then inserted in the plating tank as a
cadmium anode. In this way, a hazardous pollutant, cadmium, is reused. On the chromium line,
further testing is necessary to establish the feasibility of recovering chromium as chromic 'acid for
reuse in the bath.
Without ion exchange, the rinsewater is subjected to an expensive wastewater treatment
process. The cost of operating the ion exchange unit is more than offset by the savings in waste-
water treatment costs and by the value of the recovered product. On the cadmium line, this cost
saving and recovery value result in a payback period of less than a year for the ion exchahge sys-
tem. On the chromium line, even without considering any recovered metal value, the wastewater
treatment cost saving alone offsets the operating costs of the ion exchange, affording a payback
period of eight years. The large difference in payback periods on the cadmium and chromium lines
Is due to rinsewater consumption (without ion exchange) of the cadmium line being much greater
than that of the chromium line. With ion exchange, the resulting savings are greater for the
cadmium line.
In addition to the direct economic benefits, the ion exchange system also reduces the
potential liability of Torrington Company as a potentially responsible party (PRP) by virtually
eliminating the risk involved during off-site transport and disposal of hazardous sludge. Torrington
is also testing other means of pollution prevention (not part of this evaluation) on the cadmium and
chromium electroplating lines. To remove carbonates from the plating tank and increase bath life, a
chiller has been installed on the cadmium line. The EMR unit evaluated in this study is also being
tested for removing cadmium from the dragout tank water. A scrubber is being installed on the
28
-------
chromium line to capture chromium mists over the plating tank. The scrubber liquid is then passed
through a separate ion exchange column to recover the chromium.
29
-------
SECTIO;N 7
REFERENCES
Battelle. Quality Assurance Project Plan (QAPP) for Cadmium Recovery from Electroplating
Rinsewater by ton Exchange. Columbus, Ohio, 1992a.
Battelle. Quality Assurance Project Plan (QAPP) for Chromium Recovery from Electroplating
Rinsewater by Ion Exchange. Columbus, Ohio, 1992b.
i
U.S. Environmental Protection Agency (EPA). Facility Pollution Prevention Guide.
EPA/600/R-92/088, May 1992. |
30
-------
APPENDIX A
EMR TEST RESULTS
Regenerant used was 8 gal of 50% NaOH in 12 gal of water. After regeneration, the
column was rinsed with 35 gal of water, to give a total regenerant volume of 55 gal. This 55 gal
was analyzed to contain 2.5 ppm cadmium and 400 ppm cyanide. Fifteen gal of water from the
dragout (still rinse) tank was added to the regenerant. This dragout water contained 2000 ppm of
cyanide and 250 ppm of cadmium, and was added to the regenerant before performing the EMR
operation. The dragout water represents an additional wastestream that Torrington is trying to
minimize.
The EMR used 4 volts, 40 amps in a 36-hr operation. The final regenerant solution (after
EMR) contained only 13 ppm of cadmium, indicating that most of the cadmium had been recovered
on the cathode. Some cyanide decomposed during the EMR operation, to a level of 1100 ppm.
The exact mechanism of cyanide destruction by EMR is not known.
31
-------
APPENDIX B
I '
WASTEWATER TREATMENT COSTS
The wastewater treatment costs for the waste rinsewater on the cadmium line are based
on the following plant information over the past year: ;
« Annual wastewater influent from theicadmium rinse is 1,920,000 gal/yr based on
continuous production of 16hr/day, 5 days/week, and 50 weeks/yr
Chemical usage based on
- 172,000 Ibs/yr of 25% NaOH at $0.09/lb i
- 3,660 gal/yr of 50% NaOH at $1.50/gal
- 11 tons/yr of chlorine gas at $550/ton cylinder ;
- 5000 gal/yr of sodium hypochlorite at $0.58/gal ;
- 1500 Ibs/yr of calcium hypochlorite at $1.11/lb ,
« Labor cost of 2 hr/day of operating time at $7/hr.
« Municipal sewer discharge fee of $1,47/1000 gal of treated water
Sludge disposal cost based on 21,000 Ibs/yr of cadmium sludge hauled away at
$0.20/lb. i
This gives an average cost of cadmium wastewater treatment of $22/1000 gal.
Wastewater treatment costs for waste rinsewater on the chromium line were based
on the following plant information over the last one year:
i *
« Annual wastewater influent of 2,205,000 gal/yr. This influent consists not only of
rinsewater from the chromium plating line, but also of rinsewater from the '<
chromating line. However, all calculations are finally converted to a unit cost
($/1,000 gal), which then applies to the 480,000 gal/yr from the chromium plating
rinsewater line.
Chemical costs are based on: ;
- 7,200 gal/yr of 30% sulfuric acid at $0.78/gal '.
- 21,000 Ibs/yr of sodium metabisulfite at $0.25/lb
- 1,000 gal/yr of 50% sodium hydroxide at $1.50/gal
Labor costs based on 2 hr/day of operating time at $7/hr
32
-------
Municipal sewer discharge fee of $1.47/1,000 gal of treated water
84,000 Ibs/yr of chromium sludge hauled away at $0.20/lb.
Therefore, the average wastewater treatment cost on the chromium rinsewater line is
approximately $15/1,000 gal.
33
-------
-------
APPENDIX C
ECONOMIC ANALYSIS OF CADMIUM RINSEWATER ION EXCHANGE
A more detailed economic analysis than the one presented in Section 4 of this report is
described here. Worksheets provided in the Facility Pollution Prevention Guide (U.S. EPA 1992)
were used for the calculations. In addition to the cadmium rinsewater data listed in Section 4, the
following values were used:
H Capital Cost (Table C-1)
- Total equipment cost of $12,225 (including ion exchange and EMR) plus
10% tax
- Total installation costs of $3,500 in Section 4 were broken down into
$1,500 for materials and $2,000 for installation (labor)
- Plant engineering and contractor engineering costs were $3,000 and
$2,000 based on the pilot ion exchange unit leasing and testing that
was conducted prior to full-scale installation
- Contingency costs of 5% of fixed capital (i.e, sum of all the above)
- Working capital based on 1 month's cost of water, energy, and filters
cost from Section 4
- 100% equity (i.e., no loan taken)
- Depreciation period of 10 yrs
- Income tax rate of 34%
- Escalation (inflation) rate of 5% -
- Cost of capital of 15%
" Table C-2 describes increased revenue, increased operating costs, reduced
waste disposal costs of ion exchange (entered as positive numbers).
Decreased revenue, decreased operating costs, and increased waste
disposal costs due to ion exchange entered as negative values denoted by
parentheses around the number).
- Cadmium recovery value of $1,036/yr
r Increase in utilities costs based on electricity and water consumption
from Section 4
- Reduction in disposal costs based on wastewater (including sludge),
regenerant, and filters treatment/disposal costs
- Increase in operating labor based on Section 4 data
- Increase in operating supplies based on NaOH required for regeneration
- Increase in maintenance costs based on labor and materials as in Section 4
- Supervision costs are 10 % of O&M labor
- Overhead costs are a percentage of O&M labor and supervision
34
-------
Table C-3 shows the revenues (recovered value) and operating savings resulting from use of ion
exchange for the first three years. Table C-4 shows the return on investment (ROI). In the first
year, the ROI exceeds 15%, which is the cost of capital (see Table C-1). Therefore, the payback
period is less than 1 year. > ;
TABLE C-1. CAPITAL COSTS FOR CADMIUM ION EXCHANGE
INPUT
CAPITAL COST
Capital Cost
Equipment
Materials
Installation
Plant Engineering
Contractor/Engineering
Permitting Costs
Contingency
Working Capital
Start-up Costs
% Equity
% Debt
Interest Rate on Debt, %
Debt Repayment years
Depreciation period
Income Tax Rate, %
Escalation Rates, %
Cost of Capital
$13,448
$1,500
$2,000
$3,000
$2,000
$0
$1,000
$45
$2,000
100%
0%
10.00%
0
10
34.00%
5.0%
15.00%
OUTPUT
CAPITAL REQUIREMENT |
Construction Year
Capital Expenditures
Equipment
Materials
Installation
Plant Engineering
Contractor/Engineering
Permitting Costs
Contingency
Start-up Costs
Depreciable Capital
Working Capital
Subtotal
Interest on Debt
Total Capital Requirement
Equity Investment
Debt Principal
Interest on Debt
Total Financing
1
j,
$13,448
$1 ,500
$2,000
$3,000
$2,000
$0
$1,000
$2,000
$24,948
$45
$24,993
$0
$24,993
I
I
$24,993
$0
$0
$24,993
- ;
35
-------
TABLE C-2. OPERATING COSTS FOR CADMIUM ION EXCHANGE
Operating Cost/Revenue , "
Marketable By products
Cadmium
Total $/yr.
Utilities
Electric
Water
Total $/yr.
Raw Materials
Chemicals
Water
Total
Decreased Waste Disposal
Water treatment
Ion X regenerant
Ion -X filters . .
I ransportation, $
Storage Drums $
Total Disposal $
$1,036
$1,036
$117
($1 ,335'
($1,218'
$0
$0
$0
$42,240
'($15]
($671
$0
$0
$42,158
Operating Labor
Operator hrs
Wage rate, $/hr.
Total $/yr.
Operating Supplies
Chemicals
Maintenance Costs
Labor
Materials
Supervision
(% of O&M Labor)
Overhead Costs
173
$7.00
$1,211
$144
$168
$420
10.0%
(% of O&M Labor + Supervision}
Plant Overhead
Home Office
Labor Burden
25 0%
20.0%
28.0%
TABLE C-3. OPERATING SAVINGS USING CADMIUM ION EXCHANGE
REVENUE AND COST FACTORS-CADMIUM STUDY
Operating Year Number
Escalation Factor
INCREASED REVENUES
Increased Production
Marketable By products
Annual Revenue
1.000
1
1.050
$0
$1 ,088
$1 ,088
2
1.103
$0
$1,142
$1,142
3
1.158
$0
$1,199
$1,199
OPERATING SAVINGS (Numbers in parentheses indicate net expense) :
Raw Materials
Disposal Costs
Maintenance Labor
Maintenance Supplies
Operating Labor
Operating Supplies
Utilities
Supervision
Labor Burden
Plant Overhead
Home Office Overhead
Total Operating Savings
$0
$44,266
C$176'
($441
($1,272
($151
$1 ,279
($145'
($446'
($398'
($319'
$42,197
$0
$46,479
($185)
($463)
($1 ,335)
($159)
$1,343
($152)
($468)
($418)
($334)
$44,307
$0
$48,803
($194)
($486)
($1,402)
($167)
$1,410
($160)
($492)
($439)
($351)
$46,522
36
-------
TABLE C-4. RETURN ON INVESTMENT FOR THE CADMIUM ION EXCHANGE SYSTEM
RETURN ON INVESTMENT-CADMIUM STUDY ;
Construction Year
Operating Year
Book Value
Depreciation (by straight- lin
Depreciation (by double DB
Depreciation
Cash Flows
Construction Year
Operating Year
Revenues
+ Operating Savings
Net Revenues
Depreciation
Taxable Income
Income Tax
Profit after Tax
+ Depreciation
After-Tax Cash Flow
Cash Flow for ROI
Net Present Value
Return on Investment
i
1
$24,948
3)
'
1
r
i
($24,993)
($24,993]
1
$19,958
$2,495
$4,990
$4,990
1
$1 ,088
$42,197
$43,285
$4,990
$38,295
$13,020
$25,275
$4,990
$30,265
$30,265
$1,324
21 .09%
2
$15,967
$2,495
$3,992
$3,992
2
$1,142
$44,307
$45,449
$3,992
$41 ,458
$14,096
$27,362
$3,992
$31 ,354
$31 ,354
$25,032
87.87%
3
$12,773
$2,495
$3,193
$3.193
3
$1,199
$46,522
$47,722
$3,193
$44,528
$15,140
$29,389
$3,193
$32,582
$32,582
$46,455
110.25%
37;
-------
APPENDIX D
ECONOMIC ANALYSIS OF CHROMIUM RINSEWATER ION EXCHANGE
A more detailed economic analysis than the one presented in Section 4 of this report is
described here. Worksheets provided in the Facility Pollution Prevention Guide (U.S. EPA 1992)
were used for the calculations. In addition to the chromium rinsewater data listed in Section 4, the
following values were used:
Capital Cost (Table D-1)
- Total equipment cost of $8,200 plus 10% tax
- Total installation costs of $3,500 in Section 4 were broken down into
$1,500 for materials and $2,000 for installation (labor)
- Plant engineering and contractor engineering costs were $3,000 and
$2,000 based on the pilot ion exchange unit leasing and testing that
was conducted prior to full-scale installation
- Contingency costs of 5% of fixed capital (i.e, sum of all the above)
- Working capital based on 1 month's cost of water, energy, and filters
cost from Section 4
- 100% equity (i.e., no loan taken)
- Depreciation period of 10 yrs
- Income tax rate of 34%
- Escalation (inflation) rate of 5%
- Cost of capital of 15%
Table D-2 describes increased revenue, increased operating costs, reduced waste
disposal costs of ion exchange (entered as positive numbers). Decreased revenue,
decreased operating costs, and increased waste disposal costs due to ion exchange
entered as negative values denoted by parentheses around the number).
- Cadmium recovery value of $1,036/yr
- Increase in utilities costs based on electricity and water consumption
from Section 4
- Reduction in disposal costs based on wastewater (including sludge),
regenerant, and filters treatment/disposal costs
- Increase in operating labor based on Section 4 data
- Increase in operating supplies based on NaOH required for regeneration
- Increase in maintenance costs based on labor and materials as in Section 4
- Supervision costs are 10% of O&M labor
- Overhead costs are a percentage of O&M labor and supervision
38
-------
Table D-3 shows the revenues (recovered value) and operating savings resulting from use of ion
exchange for the first three years. Table D-4 shows the return on investment (ROI). In the eighth
year, the ROI exceeds 15%, which is the cost of capital (see Table D-1). Therefore, the payback
period is approximately 8 years.
TABLE D-1. CAPITAL COSTS FOR CHROMIUM ION EXCHANGE
INPUT
CAPITAL COST
Capital Cost
Equipment
Materials
Installation
Plant Engineering
Contractor/Engineering
Permitting Costs
Contingency
Working Capital
Start-up Costs
% Equity
% Debt
Interest Rate on Debt, %
Debt Repayment, years
Depreciation period-
income Tax Rate, %
Escalation Rates, %
Cost of Capital
$9,000
$1,500
$2,000
- $3,000
$2,000
$0
$875
$15
$1,750
100%
0%
1 0.00%
0
10
34.00% i
5.0%
15.00%
OUTPUT :
CAPITAL REQUIREMENT
Construction Year '
Capjtal Expenditures
Equipment
Materials
Installation
Plant Engineering
Contractor/Engineering
Permitting Costs
Contingency
Start-up Costs
Depreciable Capital
Working Capital
Subtotal
Interest on Debt
Total Capital Requirement
Equity Investment
Debt Principal
Interest on Debt
Total Financing
: 1
«
$9,000
$1,500
$2,000
$3,000
$2,000
$0
$875
$1,750
$20,125
$15
$20,140
$0
$20,140
'
$20,140
$0
$0
$20,-140
' l
39
-------
TABLE D-2. OPERATING COSTS FOR CHROMIUM ION EXCHANGE
Operating Cost/Revenue
Marketable By products
Chromium
Total $/yr.
Utilities
Electric
Water
Total $/yr.
Raw Materials
Chemicals
Water
Total '
,
Decreased Waste Disposal
Water treatment
Ion X regenerant
Ion -X filters
Transportation, $
Storage Drums $
Total Disposal $
$0
$0
$112
($327
($215
$0
$0
$0
$7,200
($131
($67]
$0
$0
$7,120
Operating Labor
Operator hrs
Wage rate, $/hr.
Total $/yr.
Operating Supplies
Chemicals
Maintenance Costs
Labor
Materials
Supervision
(% of O&M Labor)
Overhead Costs
149
$7.00
$1,043
$360
$168
$60
10.0%
(% of O&M Labor + Supervision)
Plant Overhead
Home Office
Labor Burden
25.0%
20.0%
28.0%
40
-------
UJ
O
U
&
z
o
o
cc
o
o
V)
in
o
<
CO
i
UJ
CL
O
Q
UJ
r*^
=
o
a:
X
o
1
CO
DC
0
' ^
<
REVENUE AND COST f
co
^
»
CO
f-
Disposal Costs
CO
CM
+^*
CO
CO
CM
CM
"-_-*
CM
W*
I
3
in
co
£
%t
Maintenance Labor
I
00
o
CO
fc
CO
'cn
CO
CO
co
^
CO
co
""
Maintenance Supplies
TICO
inlm
s
CO
co
s
CO
§
ti
CO
CO
T
CO
fe
CM_
'
0
in
3t
cn
0
Q
Q
O
tO
U)
w
CD
a
2*
§
1
cn
in
t&
CO
CO
69-
1
^^
O^
CO
CO
^
Operating Supplies
CO
CO
w*
1
y*
§
CM
CM
69-
CO
CM
«
O)
CM
CO
CM
69-
CO
CM
CM
«>
CO
CD
3
£
^2
^^
tit
§
in
in
T
^O"
^*»
O
T
C?)
<&
CM
^
Supervision
5
in
in
***
§
fp
^^
<&
s
CM
CO
^
co
§"
W1
s
T
CO
W
*
IS
CO
§
s-
w-
CO
§
cn
Inl'S
COICM
1
1
s
cn
^
Plant Overhead
o
CO
CM
<«
Home Office Overhead
CM
S
CO
M
co
CO
CO
6S-
CO
in
&»
in"
coi
col
ml
CO
m
o
in
49-
i
4£.
U)
O)
_C
CO
0)
i
CD
Q.
O
ca
"5
41:
-------
UJ
(9
O
X
ui
z>
i
o
(£.
I
O
cc
o
LL.
H
LU
CO
01
&
z
o
cc
3
t
o
Ul
CO
<
D
CO
2
O
X
J
1
".
01
^
t
LU
RETURN ON INV
Construction Yea
CO
CO
in
CO
CM
T~
fe
CD
!?
i5
5
a
ta
CO
&
CM
ta
cc
cv
ta-
S3
CO
ta-
Si
co~
ta-
CO
^
c
CO
CM
8
CO
t»
in
o"
M
ta-
CD
3
5
£
Q
C'J
O
CM"
C'J
c
CM
ta-
cc
o
CM
ta-
CO
0
CM
ta-
CO
o
CM"
ta-
CO
o_
CM
ta-
CO
Q
CM
CO
O
CM
*~*
C.
^51
J.
n>
3
i/)
a_
5
|
Q
u=
>s
«
cc
ta-
CO
Si
t»
CD
s
ta-
cvi
CO
(.M
ta-
CM
CO
ta-
in
M
ta-
ff?
CO
J2
J
Q
T3
Q
0
S
D
I
!co
O
CM
CO
0
c\
CO
o
c\
CO
o
CM
ta-
s
C\i
CO
«*
s
CO
ta
in
ta-
Depreciation
"
1
1
!
<3
D
5
3
2
o
5
co
CO
in
CO
CM
~
1
35
1
5
Q.
y
;S
O
ta
&
c
o
£
0
o
Revenues
5
CD"
fe
cc
cc
CO
fs.
cc
i
in
ta-
if.
§
in
CO
co
o
in
ta-
I
-a-
O)
O5
i
CO
o
2
CO
a.
CM
co
' co"
a
cc
CO
CO
ta-
S
CO
IT
§
CO
1C
8
in
ta-
CO
g
in
ta-
I
rj-
Net Revenues
CO
o
'CM
ta
CO
o
c\
CO
o
CM
ta-
CO
o
c\
§
c\
CO
LO
CM
t»
1
CO
ta-
b
^"
i
3
CJ
D
1
D
1
Ol
ta-
V,
CO
CO
ta-
CM
CO
ta-
CO
s
co
ta-
S
CM
ta-
CO
CO
CO
CO
5
ta-
D
I
CO
1
CM
8
ta
OJ
in
CO
i
X
CO
CO
"
in
1
ta-
co
CO
CO
ta-
-
ta-
- Income Tax
CO
co
oo
CO
in
a
CM
ta-
IT
c\
in
18
CM
ta-
O)
CO
cc
0,
CM
C\J
CO
£
0
CO
CJ
ta-
co
in
ta-
1
CD
S
I
CO
o
CM
ta
CO
c
CM
ta
CO
o
CV
ta-
CO
o
cv
i
CV
ta
o
a
CM
ta-
1
co"
ta-
rt
f
ta-
5
3
|
Q
CC
in
ta
cc
if.
cv
ta-
cc
5
Oi
O
cc
ta-
i
ta-
rt
ta-
rt
in
ta-
y.
6
LU
35
ca
i
§
<
o
co
in
ta
cc
V.
cv
«r
ta-
§
in
ta-
C3)
ta-
CO
§
ta-
1
ta-
CO
n
ta-
o'
r\\
ta-
D
5
Z
L.
S
8
T
ta
CO
S
«
s
CO
«
en
o,
IT
*«
o
o
'T
w
in
O3
O)
ta-
o
CM"
:M"
-------
APPENDIX E
STANDARD ANALYTICAL METHODS FOR RINSEWATER ANALYSIS
Analyte
Cadmium
Chromium
Iron
Cyanide
pH
Total dissolved solids
Total suspended solids
Sodium
Conductivity
Standard
EPA 3010, EPA 6010
EPA 3010, EPA 6010
EPA 3010, EPA 6010
EPA 335.3
EPA 150.1
EPA 160.1
EPA 160.2
EPA 3010, EPA 6010
EPA 120.1
43i
-------
APPENDIX F
COMPLETENESS
Sampling completeness is the percentage of samples actually collected out of those
proposed in the QAPP. Analytical completeness is the percentage of valid results obtained from
the collected samples. Tables F-1 and F-2 list the sampling and analytical completeness for the
samples on the cadmium and chromium lines respectively. Wherever completeness was less than
100%, the impact is discussed in Section 5 of this report.
44
-------
TABLE F-1. COMPLETENESS FOR CADMIUM ION EXCHANGE SAMPLES
Sampling Completeness (%)/Analytical Completeness (%)
Sample Category
Conductivity TSS
TDS Cadmium Cyanide
PH
Iron
"Before" and "after"
ion-x samples
Baseline (beginning,
middle, and end of
day)
Spikes "before" and
"after" ion-x
Regenerant "before"
and "after" EMR
Field blank
100/100 100/100 100/100 100/100 100/100 100/0"" i 100/100
100/100 100/100 100/100 100/100 100/100 100/0(a) i 100/100
NRW
NR
NR NR 100/100 100/100 NR' ;. NR
NR NR 100/100 100/100 NR NR
100/100 100/100 100/100 100/100 100/100 100/0(al i 100/100
(a) Holding time for pH exceeded by a day.
(b) NR = not required.
TABLE F-2. COMPLETENESS FOR CHROMIUM ION EXCHANGE SAMPLES
Sampling Completeness (%)/Analytical Completeness (%)
Sample Category Chromium pH Conductivity TSS
TDS"
Iron
Sodium
"Before" and "after" 100/100 100/100
ion-x samples
Baseline (beginning, 0/0 0/0
middle, and end of
day)*1
Spikes "before" and 100/100 NR
"after" ion-x
Regenerant(cl 50/100 50/100
"before" and "after"
EMR
100/100 100/100 100/0
0/0'
NR
NR
0/0 0/0
NR
NR
NR 50/0
100/100 | NR
0/0 NR
NR NR
50/100 50/100
Field blank
100/100 100/100 100/100 100/100 100/0 100/100 100/100
(a) Precision for TDS was slightly out of range.
(b) No baseline samples were collected because the capacity of the resin was too small.
(c) Regenerant "before" cation-x could not be isolated for collection.
45
-------