EPA-600/2-77-090
May 1977
SODA ASH TREATMENT OF NEUTRALIZED MINE DRAINAGE
by
David A. Long, James L, Butler, and Michael J, Lenkevich
Gwin, Dobson & Foreman, Inc.
Altoona, Pennsylvania 16603
Grant 14010 ELB
Project Officer
Roger C. Wilmoth
Resource Extraction and Handling Division
Crown Mine Drainage Control Field Site
Rivesville, West Virginia 26588
INDUSTRIAL ENVIRONMENTAL RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OHIO 45268
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DISCLAIMER
This report has been reviewed by the Industrial Environmental Research
Laboratory, U.S. Environmental Protection Agency, and approved for publication.
Approval does not signify that the contents necessarily reflect the views and
policies of the U.S. Environmental Protection Agency, nor does mention of
trade names or commercial products constitute endorsement or recommendation
for use.
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FOREWORD
When energy and material resources are extracted, processed, converted,
and used, the related pollutional impacts on our environment and even on our
health often require that new and increasingly more efficient pollution
control methods be used. The Industrial Environmental Research Laboratory -
Cincinnati (IERL-Ci) assists in developing and demonstrating new and
improved methodologies that will meet these needs both efficiently and
economically.
This report is a product of the above efforts. It documents the
technical effectiveness and cost of full-scale treatment of a mildly
acidic mine drainage source by the lime/soda softening process to produce an
effluent suitable for augmenting the domestic and industrial water supply
for the City of Altoona, Pennsylvania. This was one of several projects
undertaken by IERL-CI to develop and demonstrate acid mine drainage
treatment and abatement processes to provide alternatives to government
and industry in the selection and design of treatment facilities to meet
the demands of the expanding extractive industry. Contact the Extraction
Technology Branch for further information.
David G. Stephan
Director
Industrial Environmental Research Laboratory
Cincinnati
m
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ABSTRACT
Utilization of acid mine drainage streams as a source of potable and
industrial water has become a major goal of several proposed acid mine drain-
age treatment schemes. From among the various schemes available, the lime
neutralization/soda ash softening process was selected for use at Altoona,
Pennsylvania.
The treatment plant, as constructed, has the capability of treating
waters from Kittanning Run (acid mine polluted) alone or in combination with
waters from other city sources to achieve: (1) neutralization and iron re-
moval to levels satisfactory for stream release, (2) softening to approxi-
mately 100 mg/1 CaCOs hardness for municipal use, and (3) softening to a
hardness of 200 mg/1 CaCOs or higher to meet industrial use requirements.
The objective of this study was to evaluate the technical and economic
feasibility of softening neutralized acid mine drainage waters by means of
the cold lime/soda ash process. The study was conducted full-scale at the
Altoona Treatment Plant located near the Horseshoe Curve area of Altoona,
Pennsylvania. Unit processes employed at the plant consisted of lime
neutralization, aeration, settling, soda ash softening, recarbonation, and
filtration.
The study was conducted over a 5-month period from August to December
1974 and for a short time in 1975. The results generally indicated that
the desired quality could be achieved. Effluent quality of 100 mg/1 hardness
cost 10 cents/cu m (37 cents/1000 gal); treatment to 200 mg/1 hardness cost
9 cents/cu m (33 cents/1000 gal).
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CONTENTS
Page
Foreword * i i i
Abstract iv
List of Figures vi
List of Tables vii
Acknowledgments vii'i
I Introduction 1
II Conclusions 2
III Recommendations 5
IV Process Description 7
V Process Engineering and Operation 10
VI Economic Evaluation 38
VII References 42
VIII Appendices 43
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FIGURES
No. Page
1 Diagrammatic of Treatment System 9
2 Probability Plot of Raw Water pH 14
3 Probability of Neutralization Stage Effluent pH 14
4 Probability of Raw Water Total Iron 15
5 Probability Plot of Total Iron Concentration:
Neutralization Stage Effluent 15
6 Probability Plot of Hardness MWSQ: Softener Effluent 18
7 Probability Plot of Total Iron Concentration MWSQ:
Softener Effluent 20
8 Probability Plot of Total and Dissolved Mn-MWSQ:
Softener Effluent 20
9 Probability Plot of Hardness, IWUQ: Softener Effluent 23
10 Probability Plot of Total Dissolved Solids:
Softener Effluent 23
11 Probability Plot of Sulfates: Softener Effluent 24
12 Probability Plot: Raw Water Sulfates 33
13 Softener Effluent Hardness vs. Soda Ash Usage 35
14. Lime Demand vs. pH 36
A-l Polyvalent Metal Ion Concentrations at Various pH's 44
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TABLES
No. Page
1 Typical Blended Raw Water Characteristics 12
2 Process Control Conditions: Municipal Water Quality Phase 17
3 Water Quality Data Comparison with EPA Proposed Standards 21
4 Process Control Conditions: Industrial Water Quality Phase 22
5 Summary of Chemical Feed Data 26
6 Comparison of Weighted Mean Values for Chemical Feed Data 28
7 Summary of Performance Data 29
8 Residual Hardness Observed at Different Temperatures 32
9 Chemical Utilization Efficiency 34
10 Summary of Cost Data: Power, Chemicals and Maintenance 40
11 Summary of Treatment Costs 41
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ACKNOWLEDGMENTS
The physical plant which was the subject of this study was constructed
with "Operation Scarlift" funds, the $500 million conservation bond issue
program administered by the Commonwealth of Pennsylvania through the Depart-
ment of Environmental Resources. The actual study was performed for DER under
grant agreement with the U.S. Environmental Protection Agency. Support of the
project by these agencies is gratefully acknowledged.
Data collection, evaluations and the preparation of this report were
under the direct supervision of technical staff of Gwin, Dobson & Foreman, Inc.
and Mr. David A. Long, Associate Professor of Civil Engineering at Pennsyl-
vania State University.
We wish also to acknowledge the splendid cooperation provided by the
City of Altoona Treatment Plant Employees and their supervisor, Mr. David
Barr in collecting samples, exercising the operational control, and, in
general, providing the overall work effort essential to conducting a project
of this type.
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SECTION I
INTRODUCTION
Lime neutralization of coal mine drainage is a well known and widely
applied process for upgrading stream water quality. When a significant
portion of the watershed available to a municipality for water supply is
affected by mine drainage pollutants, the question as to whether or not
neutralized mine drainage can be economically treated to a more beneficial
use level becomes a logical consideration. The $4.8 million water treatment
plant at Altoona, located in south-central Pennsylvania, was constructed
with "Operation Scarlift" funds* with a view to addressing both of these
problems, i.e., stream pollution abatement and municipal water supply.
The watershed involved drains a portion of the mountainous area to the
southwest of Altoona in the vicinity of Penn Central Railroad's well-known
Horseshoe Curve. The after effects of deep mining coal in this region has
rendered two streams acid, -- Glen White Run and Kittanning Run. The latter,
with only half the drainage area, is about seven times more acid than Glen
White Run. Early in Altoona's history, a series of three raw water reser-
voirs, together with transmission lines, were constructed to provide a water
supply for the City during periods when the high quality source (Mill Run
Reservoir) became depleted. Under normal conditions, the backup reservoir
system in the Horseshoe Curve Area consisted primarily of the better source,
Glen White, with Kittanning Run bypassing the impoundments altogether.
During severe drought, however, there were times when the highest reservoir
(Kittanning Point) was fed by the Kittanning Run source, and this poor
quality of water was the only one available to City consumers.
The rationale for the new treatment plant was to provide two levels of
treatment: 1) lime neutralization of Kittanning Run to meet stream release
standards (pH 6.0 to 9.0 and iron 7.0 mg/1), and 2) lime neutralization and
lime/soda ash softening of the reservoir system supply, fed by the Glen
White source, to meet recommended (USPHS) potable water standards. Our study
was prompted by the question, would it be technically and economically
feasible to treat the Kittanning Run raw water source to a more beneficial-
use quality? It was the main objective of this project to develop the basis
for considering this question within the limits imposed by the available
treatment units.
*Pennsylvania bond issue money ($500 million),
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SECTION II
CONCLUSIONS
A basic requirement of the study method utilized was that a relatively
constant hydraulic 13,200 cu m/day (3.5 mgd) and mineral loading should be
applied to the treatment process. In this regard, certain qualifying factors
should be mentioned prior to discussing the major findings of the study.
First, since the Kittanning Run (K.R,) source is an open channel flow, weather
(rainfall) caused some variation in raw water quality. This condition could
be controlled using K.R. exclusively or by blending the total flow in K.R.
with constant quality Impounding Dam (I.D.) water, a fairly successful pro-
cedure so long as K.R. flow did not exceed the maximum 13,200 cu m/day
(3.5 mgd). Temperature, however, was a parameter which could not be control-
led.
Another equally important factor was the inability to obtain consistent
softener operation with reaction zone solids and good clarification, This
situation was a two-edged problem inasmuch as it was necessary to evaluate
nontypical process performance of the unit as well as delay filter startup
because of this condition. Data collection of this process was thereby
limited for fear of prematurely fouling the filter media. The following
conclusions were drawn from the study:
1. Coal mine drainage (average characteristics of pH 3.0, acidity
160 mg/1, iron 14.5 mg/1, and manganese 4,5 mg/1) was treated
by the neutralization and lime/soda ash process to produce a
finished water quality that will generally meet the EPA National
Interim Primary Drinking Water Regulations.
2. The cost of producing a water suitable for blending with a
potable supply from the subject drainage source is about 10
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was present as filterable suspended solids with only 0.1 mg/1
dissolved iron.
5. The light fragile iron hydroxide floe formed intheslow mix and
aeration tanks was easily broken up by turbulent flow caused by
the fall from the aeration tank effluent weir into the collection
trough. Settling and iron removal were adversely affected by
this condition. Adding coagulant aid (cationic polymer) to the
sedimentation basin influent significantly improved settling and
resulted in a more compact sludge.
6. The most effective removal of manganese was accomplished by the
addition of potassium permanganate to the raw water influent line
ahead of the neutralization stage. If no potassium permanganate
was used, the most effective manganese removal was observed at
pH 11.0.
7. Magnesium removal (raw water magnesium 18 mg/1) in the neutralization
stage was pH dependent according to the following schedule: pH 7.0
resulted in very little reduction, pH 9.0 to 9.5 caused a reduction
of about 50%, and pH 11.0 to 11.5 resulted in removal of practically
all of the magnesium (1 mg/1 remaining).
8. The total aluminum applied to the softening stage was fairly constant,
averaging 2.5 mg/1. Soluble aluminum,however, varied with pH in the
sedimentation basin effluent from 1 mg/1 at pH 7,0 to 2.5 mg/1 at
pH 11.0.
9. The softener unit operation employed was of the solids contact type
that requires the return of settled solids to the reaction zone for
intimate mixing of previously formed floe with the applied flow and
chemical addition. The buildup of reaction zone solids (10-15%
settleable solids by volume in 15 minutes) was a prerequisite for
efficient reaction and effective clarification according to the
manufacturer. With the exception of approximately 3 weeks during
the study, it was impossible to obtain the recommended type of
softener operation. The reason for failure of the unit to buildup
solids is not understood.
10. The operating conditions under which reaction zone solids could be
generated required a pH of 11.0 or higher. During these test periods
the neutralization stage pH was 7.0 to 8.0. Heavy floe carryover
from the sedimentation basin was characteristic of this first-stage
operation. It was determined, however, that good softener operation
at pH 11.3 also could be obtained without the presence of heavy
floe carryover from the first stage. The favorable softener opera-
tion with a desired level of reaction zone solids was accomplished
during periods when the water temperature was above 12°C. At water
temperatures below 10°C, the desired softener process operation could
not be reproduced.
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11. The general appearance of the softener effluent for the most part
could be characterized as a turbid, homogeneous quality of water
containing a finely divided precipitate. Samples drawn from various
levels and zones within the tank failed to show any distinct differ-
entiation in the liquid contents which would indicate significant
solids buildup.
12. The use of alum and/or coagulant aids (CA 233 and CA 253) was not
effective in improving the coagulation - flocculation process in the
softener.
13. The capacity of the recarbonation unit was not sufficient to lower
the pH of the softener effluent below 9.5 when the softener process
was operated at a pH in excess of 11,0. The carbon dioxide feed
capacity was 682 kg/day (1500 lb/day) or about 51 g/cu m (428 Ib/MG)
of water to be treated.
14. A severe filter plugging problem was experienced during the period
from October 23 to 28. It was suspected that the cause for this con-
dition was due, at least in part, to coagulant aid fouling of the
top 10to 15 cm (4 to 6 in) of the filter media.
15. Settled solids in the thickener could not be effectively moved to the
center collection well. The fluid characteristics of the sludge
resulted in a condition whereby the solids accumulated in a ring
approximately one third to half way from the periphery of the tank.
Air lancing was partially successful in moving the sludge to the
tank-center. Ultimately, it was necessary to lower the level in
the thickener and hose the solids toward the middle sump.
16. The total amount of metered lime fed to the process could be accounted
for based on theoretical lime requirements and observed results.
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SECTION III
RECOMMENDATIONS
It should be clearly understood that the treatment units and the process
discussed in this report were not designed or intended to treat the Kittan-
ning Run source of mine drainage to a degree better than that required for
stream release,i.e.,pH 6.0 - 9,0 and iron 7.0 mg/1 or less. However, having
the opportunity to observe the complete system with Kittanning Run as the raw
water source has provided valuable operating experience relative to applying
better treatment if the need arises. It is in reference to this possible
application, as well as other general problem areas, that the following
recommendations are made:
1. Conventional design criteria will generally apply to the softening
process (lime/soda ash) so long as the water temperature remains
above 54°F (12°C). It is assumed that if Kittanning Run or a
similar quality of raw water were to be treated, impoundment would
be provided, so in all probability, temperature below this threshold
level would not be experienced.
2. Turbulence should be avoided at transfer points in the system after
mixing and particularly ahead of the clarifier to minimize floe
breakup.
3. The use of potassium permanganate should be limited to head-end
of the plant application. This study indicated that the addition
point ahead of neutralization (7 hours before the softening unit)
was best. Potassium permanganate feed directly to the softener
was very difficult, if not impossible, to control.
4. Application of the particular solids contact type of softener unit
used in this study appears questionable.
5. Design of the thickener unit operation for handling a mixture of iron
hydroxide/calcium carbonate solids should take into consideration
the tendency of this type of sludge to "doughnut," or resist movement
to the tank center. The bottom slope in the unit available for the
study was about 14.5%. Increasing the floor slope would facilitate
sludge removal and solids control.
6. Provision should be made for feeding coagulant aid to the sedimenta-
tion basin (ahead of softening) inlet line. This capability is
important because of the characteristic light iron hydroxide floe
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formed in the neutralization stage. In general, flexibility in
chemical addition points is most desirable.
Our data analysis indicates that though on occasion a softener
effluent hardness of less than 100 mg/1 CaCOs was obtained, we
could not expect an average of much less than 120 mg/1, regardless
of the amount of soda ash fed. This result must be interpreted
with some caution because the process condition did not afford
control of temperature, softener reaction zone solids, or continuous
filter operation. Where a specific application of this treatment
process is being considered, it would be advisable to determine
this minimum achievable hardness level in the laboratory.
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SECTION IV
PROCESS DESCRIPTION
The treatment system available for study under this project is shown
diagrammatically in Figure 1, The operational units employed are grouped
together according to the major process objectives, neutralization, softening
and sludge handling. The first stage, or neutralization process, consists
of the flash mix, slow mix, aeration and sedimentation units, Detention times
in this flow-through sequence are 25 seconds, 25 min, 1.1 hr, and 6.17 hr
respectively based on a flow of 13,200 cu m/day (3,5 mgd). Settled solids
are pumped from the sedimentation basin at a controlled rate to the flash
mix (recycled sludge) and to the thickener clarifier (waste solids). Lime
slurry is fed to the flash mix in a controlled amount to maintain the pH
called for in the slow mix tank. In addition, as a result of this investi-
gation, provision has been made to feed potassium permanganate into the
influent raw water line.
Effluent from the first stage sedimentation basin meets stream release
water quality and, in the case of Kittanning Run, would normally be discharged
from the plant. For purposes of this study, however, the effluent was directed
to the mix box where lime can be added prior to softening and recarbonation.
The softener unit is a circular tank arranged with separate compartments to
provide zones for rapid mix, flocculation, and clarification (Walker Process
Clariflow Unit). In theory, the unit is designed to pump settled solids
from the bottom-center of the tank back to the reaction zone. Chemicals
(soda ash, alum, coagulant aid, and potassium permanganate) can also be fed
at this point to allow for mixing of the applied flow with previously formed
floe and chemicals so that the required reactions, coagulation, and floc-
culation can occur. Theoretical residence times for the reactor and settling
zones are 25 minutes and 83 minutes respectively. Flow from the softener is
to the recarbonation chamber 12.2m x 2.4m x 3.0m (40'x 8'x 10') where carbon
dioxide is added. Recarbonation detention time for the 13,200 cu m/day
(3.5 mgd) flow is 10 minutes. The effluent from the recarbonation unit is
filtered prior to clearwell storage and chlorination.
The major components of the sludge handling process are the thickener
clarifier, holding tank and vacuum filters. For purposes of this discussion
the backwash lagoons, which receive backwash water from the filters,
filtrate from the vacuum filter, and thickener overflow, also are included
in the solids handling operation. The thickener receives underflow solids
from the first stage (sedimentation basin) and the second stage (softener).
Thickened sludge is pumped to a holding tank and from there to the vacuum
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filters as required. The vacuum filters are elevated so that the sludge
cake can be conveyed to a hopper and periodically loaded on a truck for
hauling to final disposal.
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NEUTRALIZATION PROCESS
AERATION
TANK
SLOW MIX
LIME POTASSIUM
I PERMANGANATE
FLASH _ I
MIX _
RAW
WATER
SLUDGE HANDLING PROCESS
SOFTENING PROCESS
RECARBONATION
CHAMBER
CARBON
DIOXIDE
TREATED
WATER
FIGURE I. DIAGRAM OF THE ALTOONA TREATMENT SYSTEM
ILLUSTRATING UNIT PROCESSES
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SECTION V
PROCESS ENGINEERING AND OPERATION
PROJECT PLAN
The project was divided into major phases. The first phase was designed
to achieve an effluent quality which would meet the requirements of the 1962
Public Health Service Drinking Water Standards (1), except for sulfate content.
Specific objectives were to produce a finished water with e'iproximately 100
mg/1 CaCOs hardness and containing no more than the permissible 0.3 mg/1 and
.05 mg/1 of iron and manganese respectively. This product water was designa-
ted as "municipal water supply quality" (MWSQ). The 1962 Standards were
selected as the basis for process control because the interim regulations
being developed under the "Safe Drinking Water Act" (2) by the Environmental
Protection Agency do not include "secondary standards" for those parameters
of concern in this study.
The second major phase of the project was intended to study the produc-
tion of an effluent designated as "industrial water use quality" (IWUQ). The
effluent target hardness for this phase was 200 mg/1 CaC03- Iron and
manganese levels were to be the same as for the municipal supply quality
phase.
In addition to the two major phases described, project data were to be
analyzed to determine the ability of the first stage process, i.e., aeration
and neutralization, to produce an effluent that would be suitable for stream
release under the Commonwealth of Pennsylvania, Department of Environmental
Resources regulations (3). In order to meet these requirements (pH 6.0 to
9.0, Fe less than 7.0 mg/1, and alkalinity greater than acidity), the process
would be operated somewhat differently than was done for the two major phases
described above.
It was possible, however, to analyze the data collected and to predict
the ability of the first-stage process to meet the requirements indicated.
Finally, although not a major consideration in this study, some
information on sludge production was generated and will be evaluated briefly
in a later section.
During each phase of the study, operational parameters were varied in
an attempt to determine the optimum operating conditions to produce the
desired effluent quality for that phase of the study. The primary parameters
which were varied were pH, amount of chemicals added, and the point of
chemical application. Various pH's were set at different stages in the over-
10
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all treatment process to see which scheme would minimize operating problems
while producing an acceptable effluent polity. To clarify this further,
during parts of the study the desired process pH was achieved initially in
the neutralization stage and then was carried right on through the softening
stage while in other parts the pH's were varied in the first stage unit as
a pre-treatment (iron and manganese oxidation stage) and the pH's for the
softening reactions were regulated in the reactor-clarifier unit.
While it would have been highly desirable to have been able to obtain
filter operating data for the duration of the project, it was not possible
to do so under the operating conditions encountered. Therefore, the majority
of the data analysis presented will be in terms of the softener and recarb-
onation basin effluent characteristics only. Filtration of the recarbonation
basin effluent would undoubtably yield effluents with somewhat different
characteristics than those reported herein but it was impossible to gather
such data during this study other than for a limited period during the second
phase. Generally, filtration would be expected to produce water with lower
hardness, iron,and manganese than reported due to "seasoning" of the filters.
The specific goals of the study were as follows:
1. Determination of the chemical dosages required to yield a finished
water which will meet specific water use criteria including:
(a) stream quality standards
(b) municipal water supply meeting the USPHS recommended limits
(100 mg/1 hardness), and
(c) industrial usage water use quality, 200 mg/1 hardness,
2. Evaluate operational problems associated with the process.
3. Determine the operating costs relevant to obtaining various
qualities of product water.
4. Evaluate the feasibility and economics of utilizing the lime/soda
ash treatment process for municipal and industrial uses on acid
mine drainage.
RAW WATER QUALITY
Raw water for the study was a blend of Kittanning Run (K.R.), a moderate
acid mine drainage affected source, and Impounding Dam (I,D.)» a better qual-
ity water. Design flow through the portion of the plant used for the study
was 13,200 cu m/day (3.5 mgd). Because the sustained yield of Kittanning Run
is less than 13,200 cu m/day (3.5 mgd), it was necessary to blend the two
sources as indicated in order to achieve the design flow. Table 1 shows the
blended water characteristics for a blend typical of that treated during the
study, i.e. , 5680 cu m/day (1.5 mgd) of K.R. plus 7570 cu m/day (2.0 mgd) of
I.D.
11
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TABLE 1. TYPICAL BLENDED RAW WATER CHARACTERISTICS
KITTANNING RUN : IMPOUNDING DAM = 1 : 1.33
Parameter Value
pH 3.0
Acidity, mg/1 as CaC03 170
Calcium, mg/1 28
Magnesium, mg/1 18
Iron, mg/1 17
Manganese, mg/1 4.5
Aluminum, mg/1 13
Sodium, mg/1 1.8
Hardness, mg/1 as CaC03* 260
Sulfates, mg/1 270
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obvious error in sampling or laboratory analysis. It was felt the data could
be presented best in the text of the report by means of probability plots that
show the statistical correlation of the data. Summaries of the complete
operating data are presented in Appendix B.
Data analysis for the preparation of the probability plots was done in
accordance with the procedures outlined in the Handbook for Monitoring
Industrial Wastewater (6). Data which are normally distributed yield a
straight line when plotted on probability paper. In some instances, abnormal
breaks in the data are observed on such plots. This observation indicates
that some change in operating conditions occurred which resulted in data
being obtained from a different distribution and hence, they do not plot along
the original straight line. These data may, however, plot on a different
straight line showing a normal distribution of data obtained under the
changed operating conditions.
STREAM RELEASE QUALITY RESULTS
As previously indicated, the requirements for stream discharge of acid
impregnated water are: (1) pH between 6.0 and 9.0 and (2) dissolved iron
not to exceed 7.0 mg/1. Only the first stage of the plant (neutralization
process, Figure 1) would be required to achieve the necessary degree of
treatment for stream release. Because the plant was not operated solely
to produce stream release quality effluent during the study, however, the
neutralization stage was operated as a pretreatment step to the softening
operation. As will be discussed in more detail in later sections, the pH in
the neutralization stage was varied from 7.0 to 11.0 to investigate the
effect of this parameter on the subsequent softening operation. The data
obtained during the study, therefore, do not reflect operating conditions
comparable to those which would be employed for acid mine drainage treatment
only.
Figures 2 and 3 are probability plots of the raw water pH and the
sedimentation basin effluent pH from the neutralization stage respectively.
Figures 4 and 5 are similar plots for total iron. As can be seen from
Figure 3, the stream release quality goal of a minimum pH of 6.0 was met
95 percent of the time. The upper pH limit of 9.0 would not be of concern
if the treatment plant was operated only to meet stream release quality
criteria. The high pH's used in this study were necessary for the softening
processes used to meet the other water quality goals. Accurate control of
pH in the range of 7.0 to 9.5 was impossible during the study so all data
for target pH's in this range were treated together for use in preparing
Figure 3. Control was much better for a target pH of 11.0 as shown by the
lesser scatter for these data in Figure 3. No definite reason for the break
in the curve for the raw water iron concentration as shown in Figure 4 was
apparent, although it may have been related to flow fluctuations with result-
ing dilution and concentration of iron in Kittanning Run. Figure 5 shows
the stream release quality goal of 7.0 mg/1 of iron was met 100 percent of
the time.
13
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40
I
tt 3.5
10
25
2.0
}.l 0.5 I 2 5 10 20 30 40 50 60 TO 80 90 95 98 99
PERCENT OF TIME ACTUAL VALUE IS EQUAL TO OR LESS THAN GRAPH VALUE
FIGURE 2-- RAW WATER pH PROBABILITY PLOT
99.9
I2X>
I l.O
PH=I
9.0
£ 8.0
TARGE
PH =
7.C
-9
|,0
111
1 6.0
8
(A
l 05 I 2 5 10 2030409060 70 80 9095 9899
PERCENT OF TIME ACTUAL VALUE IS EQUAL TO OR LESS THAN GRAPH VALUE
FIGURE 3' SEQ BASIN EFFLUENT pH PROBABILITY PLOT
99.9
14
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OS I 2 5 10 20304050607080 9099 9899
PERCENT OF TIME ACTUAL VALUE IS EQUAL TO OR LESS THAN GRAPH VALUE
FIGURE 4: RAW WATER TOTAL IRON PROBABILITY PLOT
99.9
l«fcU
12.0
10.0
c
E 8JO
o
a:
~ 6JO
L
zo
°a
^
>^
^«
^-^
«^^
f**
^
^~
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^
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1 O3 I 2 5 10 20 SO 40 90 6O 70 80 9095 9899 99.
PERCENT OF TIME ACTUAL VALUE IS EQUAL TO OR LESS THAN GRAPH VALUE
FIGURE 5'. SED. BASIN EFFLUENT TOTAL IRON PROBABILITY PLOT
15
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Optimization of the neutralization stage to meet stream release require-
ments would have to be done independently of the softening operation in order
to develop the most cost effective mode of operation. It was observed that
when the pH in the neutralization stage was maintained at approximately 7.0
there was some carryover of large floe particles from the first stage sedi-
mentation basin. An attempt was made to reduce this floe carryover in order
to determine its effect on the operation. Any such reduction in floe
carryover should result in lower total iron residuals in the effluent
from this stage and hence would be advantageous in meeting the stream dis-
charge requirements. An attempt was made to improve solids separation in
the first stage by partially closing the valve in the sedimentation basin
inlet line. This change was made to maintain a higher water level in this
effluent channel from the aeration basin. Floe breakup should have been
reduced under these operating conditions because free fall into the effluent
weir trough was eliminated. This modification in operating conditions did
not reduce the floe carryover significantly. In a further attempt to
improve clarification, a coagulant aid (Calgon 233) was added into the
sedimentation basin influent line while operating under the two conditions
described above. The dosage of CA 233 was set at 1 mg/1, the maximum con-
centration permitted by EPA ( 7 ) . Some improvement in clarification was
noted but not enough data were collected to make a comparative analysis of
its effect on total iron removal.
MUNICIPAL WATER SUPPLY QUALITY RESULTS
For the purposes of this project, municipal water supply quality was
defined as treated water having a total dissolved solids (TDS) content of
less than 500 mg/1. Further, the target hardness for the treated water
during this portion of the study was 100 mg CaC03/l. Also, as indicated
earlier, effluent limits for iron and manganese were 0.3 mg/1 and 0.05
mg/1, respectively.
During this phase of the study, data were collected over a total of
74 days which were divided into 11 different operating periods. Process
control conditions for these periods are summarized in Table 2. Because
of operating problems with the softening unit, which will be discussed in
more detail later, it was deemed advisable to vary pH's and other operating
parameters as shown in an attempt to improve performance of the softening
unit.
16
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Examination of the characteristics of the typical blended raw water in
Table 1 indicates that about 28 percent of the total hardness (TH) is due to
magnesium (73 of 255 mg/1 as CaC03). The target hardness of 100 mg CaC03/l,
therefore, should have been achievable by leaving most of the magnesium in
the water and by removing calcium hardness down to its minimum practical
solubility of 30 to 40 mg CaC03/l. One concern, however, with this approach
is the potential problem of magnesium silicate scaling in the high temperature
service, such as boiler feedwater application, when the magnesium hardness
exceeds 40 mg CaCOo/1 (8). Assuming magnesium hardness of approximately 70
mg CaC03/l is acceptable, the desired hardness should have been achieved by
maintaining the softener pH at approximately 9.5 and by using conventional
lime/soda ash softening operational parameters. Soda ash addition to remove
non-carbonate hardness (NCH) could then be used to control the effluent
total hardness.
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Oi O.S I 2k 5 C 20304090607080 9O 95 9699 99.9
PERCENT OT TIME ACTUAL VALUE IS EQUAL TO OR LESS THAN GRAPH VALUE
FIGURE 6 SOFTENER EFFLUENT TOTAL HARDNESS MUNICIPAL
WATER SUPPLY QUALITY PROBABILITY PLOT
Figure 6 is a probability plot of the softener effluent total hardness
for all data collected during this phase of the study, As indicated by this
figure, the target hardness of 100 mg CaC03/l was achieved only approximately
30 percent of the time. Effluent hardnesses of 125 mg CaC03/l or less were
obtained approximately 70 percent of the time and 85 percent of the time the
effluent hardness was 150 mg CaC03/l or less. It is believed the primary
reason for the poor performance of the softening operation was the inability
to adequately build up and retain solids in the reaction zone of the Clari-
flow unit. Successful solids-contact softener operation is highly dependent
upon having enough preformed crystals in the reaction zone to increase the
rate of chemical reactions in the process. This point will be discussed
further in a later section. The problem of maintaining pH control in the
18
-------
range of 7.0 to 9.5 discussed previously made proper control of the softening
process difficult and this lack of control may be part of the reason for poor
overall performance. Because of the inability of the recarbonation unit to
reduce the pH to desired levels during some operating conditions it was not
possible to fully evaluate the effect of recarbonation on effluent hardness.
As was discussed earlier, it was not possible to operate the filters during
this portion of the study so the effect of filtration of the softener effluent
was not obtained.
Figure 7 is a probability plot of the softener effluent total iron data
collected during this phase of the study. This plot shows that the drinking
water standard of 0.5 mg/1 was achieved only 70 percent of the time. All
dissolved iron values, however, were less than 0.2 mg/1 and a total of
61 out of 72 data points for dissolved iron showed less than 0.1 mg/1 of iron
so effective filter operation should yield an effluent that would meet the
standards without any difficulty.
Softener effluent total and dissolved manganese probability plots are
shown in Figure 8. As can be seen from these plots, the drinking water
standard limit of 0.05 mg/1 was achieved 65 or 80 percent of the time de-
pending on whether total or dissolved values were used. Manganese oxidation,
which is normally the rate limiting step in the removal of manganese from
potable water, proceeds rather slowly at phi's between 8.5 to 9.5. During
those periods of the study when the neutralization stage was being operated
at pH's less than 8.5 and because of the poor pH control achieved,
effluent manganese values were often too high to meet the standards. It is
entirely possible that filter effluent manganese values would be significant-
ly lower than those observed due to the catalyzing effect of "seasoned"
filters on manganese removal. As stated previously, however, it was not
possible to evaluate this during the study.
Data were not collected routinely for those substances listed in the
national interim primary drinking water regulations developed by EPA (9),
but the results of one set of analyses (reported in Table 3) indicate that
effluent from the plant could be expected to meet the standards for those
substances that were measured. Not all of the substances included in the
proposed standards were included in the analyses performed.
INDUSTRIAL WATER USE QUALITY RESULTS
As was indicated earlier, for the purposes of this study, industrial use
quality water was defined as treated water with total dissolved solids in
excess of 500 mg/1 and a hardness of approximately 200 mg CaC03/l. Effluent
limits for iron and manganese were the same as for the municipal water
supply quality phase. This phase of the study was divided into six different
operating periods which included a total of 34 days of operation and data
collection. The process control conditions for these periods are summarized
in Table 4. As noted in the table, the major changes in operation compared
with that used for the first phase of the study were: 1) the addition of
potassium permanganate to facilitate oxidation of manganese and 2) the
operation of the filters for the major portion of this phase. Of course,
the soda ash dosage was reduced from that used in Phase I in order to achieve
19
-------
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12
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the desired high effluent hardness.
TABLE 3. WATER QUALITY DATA COMPARISON WITH EPA NATIONAL
INTERIM PRIMARY DRINKING WATER REGULATIONS
Parameter (1
Arsenic
Barium
Cadmium
Chromium
Cyanide
Lead
Mercury
Nitrate
Selenium
Silver
Fluoride
Copper
Zinc
Raw
) Kitt.
Run
0.030
0.05
0.004
0.010
0.005
0.030
--
--
0.010
--
0.33
0.3
1.1
water
Imp. Neutralization
Dam stage
0.030
0.05
0.004
0.010
0.005
0.030
--
--
0.010
--
0.19
0.020
0.15
0.030
0.05
0.004
0.010
0.005
0.030
--
0.010
--
0.29
0.010
0.070
Recarb. basin
eff.
0.030
0.05
0.004
0.010
0.005
0.030
--
0.010
--
0.29
0.010
0.030
Proposed (8)
int. Primary
standards
0.05
1.
0.010
0.05
0.2
0.05
0.002
10.0
0.01
0.05
1.4 - 2.4
1.0*
5.0*
NOTE: All values are mg/1; the test results are from Reference 10
1962 USPHS Drinking Water Standards.
21
-------
TABLE 4. PROCESS CONTROL CONDITIONS FOR
INDUSTRIAL WATER USE QUALITY PHASE
Target pH
Period Neut. Stage Soft Stage Comments
Oct. 17-22 9.5 11.4 No recarbonation, filtration.
Calgon 253 added @ 1 mg/1
Oct. 28 - Oct. 31 8.5-9.0 11.3 Recarbonation; no filtration
Nov. 1-10 8-5-9.0 11.3 Recarbonation and filtration
Nov. 11-17 8.5 11.3 Recarbonation (4 days), filtra-
tion; KMn04 feed (10 mg/1) into
I.D. Influent line.
Nov. 18-21 8.5 10.5 No recarbonation, filtration,
KMn04 feed (10 mg/1) into I.D.
influent line
Nov. 22-24 8.5 10.5 Recarbonation (2 days) filtration
Figure 9 is a probability plot of the softener effluent total hardness
for all of the data collected during this phase of the study. As can be seen
from this figure, the target hardness of 200 mg CaC03/l was achieved approxi-
mately 65 percent of the time with an effluent hardness of 225 mg CaC03/l or
less approximately 90 percent of the time. Comparison of filter effluent
(clearwell) data with the softener effluent data for that portion of Phase II
when the filters were in operation showed approximately 4.5 percent reduction
in hardness through the filters (192 mg CaC03/l in the clearwell compared
with 201 mg CaC03/l in the softener effluent based on weighted mean values).
Iron and manganese data obtained for this phase of the study were quite
similar to those obtained during the municipal water supply quality phase and
presented earlier. All values for dissolved iron in the softener effluent
were below 0.1 mg/1. The weighted mean value for total iron in the softener
effluent during the period the filters were in operation was 0.55 mg/1 as
compared to 0.18 mg/1 in the filter effluent. These values show that filtra-
tion resulted in a 67.3% reduction in total iron and resulted in levels well
below the drinking water goal of 0.3 mg/1. Only two values for dissolved
manganese exceeded 0.05 mg/1 during this period of data collection. Filtra-
tion of the softener effluent resulted in appreciably lower values for total
manganese as evidenced by the weighted mean value of 0.03 mg/1 for filter
effluent as compared with 0.19 mg/1 for the softener effluent; an 84.2
percent reduction.
Figures 10 and 11 are probability plots of the total dissolved solids
and sulfates for all data collected during the entire study. These figures
show the softener effluent met USPHS drinking water standards for these
22
-------
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1 as 12 5 O 20304050607080 9095*9899 99.9
PERCENT OF TIME ACTUAL VALUE IS EQUAL TO OR LESS THAN GRAPH VALUE
FIGURE 9 : SOFTENER EFFLUENT TOTAL HARDNESS INDUSTRIAL
WATER USE QUALITY PROBABILITY PLOT
TOTAL DISSOLVED SOLIDS - mg/l
M * © OB O f\) J
f* O O O O O O t
p° o o o o o o c
ML
NIC
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PERCENT OF TIME ACTUAL VALUE IS EQUAL TO OR LESS THAN GRAPH VALUE
FIGURE 10 : SOFTENER EFFLUENT TOTAL DISSOLVED SOLIDS
PROBABILITY PLOT
23
-------
constituents most of the time irrespective of whether the operational
target was municipal water supply quality or industrial water use quality
No appreciable removal of sulfates were anticipated with the processes used.
It should be pointed out again, however, that the raw water was not taken
solely from Kittanning Run, the acid mine drainage impregnated stream, and
hence, the raw water was lower in total dissolved solids and sulfates than
had been anticipated.
SLUDGE PRODUCTION CONSIDERATION
Because the major emphasis in this study was directed towards effluent
quality, chemical usage, operational considerations, and cost, only general
data on sludge production was collected. The process flow diagram of the
TOO
0.1 0.5 12 5 10 20304090607080 90999699
PERCENT OF TIME ACTUAL VALUE IS EQUAL TO OR LESS THAN GRAPH VALUE
FIGURE II SOFTENER EFFLUENT SULFATES PROBABILITY PLOT
99.9
plant shown in Figure 1 schematically illustrates the sludge handling pro-
cedures utilized. Underflow from both the neutralization stage sedimentation
units and the Clariflow softener units was thickened in a gravity thickener.
Thickened sludge was then vacuum filtered and the resulting sludge cake was
landfilled.
It was decided that the best estimate of the amount of sludge produced
and handled from the neutralization and softening stages could be obtained
from a tally of the number of truck loads of filtered sludge hauled out for
disposal. It was estimated from a limited amount of data on filter cake
characteristics that each truck load contained approximately 2600 Kg (5700
Ibs) of dewatered cake (approximately 25-percent total solids). A total
of 390 truck loads of sludge were hauled out over the duration of the study
24
-------
(Aug 12 - Dec. 8, 1974). The estimated sludge production from the overall
process, therefore, was 690 kg (1520 Ibs) of dewatered cake per 1000 cu m
(.264 MG) of water processed. It was not possible to determine what fraction
of the total sludge came from the neutralization stage and how much was
generated in the softening operation. From the limited data available,
vacuum filter yields ranged from approximately 37 kg (82 Ibs) to 57 kg (126
Ibs) of dewatered cake per square meter (10.8 ft) per hour. The sludge
filtered well and no unusual operating problems were encountered.
CHEMICAL FEED CONSIDERATIONS
A complete discussion of the theoretical requirements for lime and soda
ash for both the neutralization and softening stages is presented in Appendix
A. All equation numbers used below refer to the chemical reactions presented
therein. A summary of the chemical feed data is presented in Table 5.
The neutralization stage lime feed data presented in Table 5 was calcu-
lated in three different ways for comparison as follows:
1. Theoretical. The theoretical lime requirement is based on the
chemical reactions (1), (2) and (4), assuming these proceed to
completion.
2. Needed. The difference between the total metal ion concentration
in the raw water and the dissolved metal ion concentration in the
first stage sedimentation basin is multiplied by the appropriate
lime demand calculated from the assumed reactions using equations
(1), (2), (4), (6), and (7). The total "needed" lime demand is the
sum of the demand for the individual reactions.
3. Observed. The observed lime demand calculations were based on the
amount of calcium increase observed from data collected during the
study.
Analysis and comparison of the results computed by the different methods,
together with an observed decrease in sulfate concentration in the first stage,
suggests that some calcium was removed from the first stage as a precipitated
calcium sulfoaluminate in accordance with the following reaction:
CaO + CaS04 + 2 Al (OH)3 H20_ 3 CaS04 A1203 CaO ' XH20
This equation was used to correct the observed values calculated in
accordance with method 3 above, based on observed sulfate loss to yield the
corrected observed values in Table 5.
The softener lime feed was calculated similarly in three ways as
follows:
1. Theoretical. The amount of lime required based on reactions
(6) and (7).
2. Needed. The amount of lime required based on observed results
25
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26
-------
for free carbon dioxide, carbonate hardness, magnesium and
manganese using equations (9), (12), and (7) respectively.
3. Observed. The observed lime demand calculations were based on the
observed calcium increase in the mix box ahead of the softener.
Soda ash dosages were also calculated in several different ways as
follows:
Method 1. The soda ash required based on the metered lime feed using
equation (13).
Method 2. This method was the same as Method 1 except the theoretical
lime requirement as defined above was used as the basis for
calculation.
Method 3. The amount of soda ash required based on observed results
using equations (14), (15), and (16).
Method 4. This method used the observed increase in sodium as the
basis for calculation and hence is similar to the method
defined as observed in the discussion on lime feed calcu-
lations.
Treatment plant records were used to determine the metered chemical usage
for both lime and soda ash. For comparative purposes, the weighted mean values
for the various methods of calculating the chemical feed requirements and the
metered values are given in Table 6. These comparisons will be discussed in
detail in the following section.
DISCUSSION
The following discussion will summarize observations made during the study
and will concentrate on operational problems encountered. Table 7 presents
summary performance data for the total study together with brief comments on
operational observations.
Neutralization Stage
As has been indicated earlier, it was not possible to optimize the neu-
tralization stage operation for the production of stream release quality water
during the study. The collected data show the effluent requirements for stream
release were easily met, however, it should be pointed out that the design
capacity of the neutralization stage facilities is 28,400 cu m/day (7.5 MGD)
although the actual flow during the study was only 13,200 cu m/day (3.5 MGD).
It is not anticipated that there would be any difficulty in meeting the
Department of Environmental Resource's requirements at the design flow even
though the detention time in the first stage clarifiers is pnly 3.08 hours.
The light fragile hydrous iron floe formed in the slow mix and aeration
basin was easily broken up as the water fell from the aeration basin effluent
weir into the collection trough leading to the sedimentation basin. Floe
27
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breakup undoubtedly resulted in reduced settling basin efficiency which is
very important if stream release quality water is being produced. As indi-
cated earlier, some modification in operating conditions did not appreciably
reduce the amount of iron floe carryover from the sedimentation basins.
Addition of a cationic polymer (Calgon 233) to the sedimentation basin
influent, however, significantly improved settling and resulted in a more
dense sludge. Optimization of the first stage sedimentation step by evaluat-
ing different coagulant aids could be done in a separate study prior to
commencing operation for the sole purpose of meeting stream release quality
objectives.
The primary function of the neutralization stage during this study was to
remove iron and manganese prior to the softening step. Iron removal did not
present any particular problems as evidenced by the stream release quality
data analysis. In fact, some carryover of iron floe from the first stage to
the softener may have improved clarification in the softening step. On the
other hand, manganese oxidation is highly dependent upon pH and the USPHS
limits on manganese were not achieved during portions of the study. Four pre-
softening stage conditions were investigated to determine the manganese removal
capabilities of the system. Summary results for the different control con-
ditions were as follows:
Manganese, mg/1
Control condition Total Dissolved
Neutralization to pH 7.0 3.90 2.80
Neutralization to pH 9.0 .50 .08
Neutralization to pH 11.1 .20 .01
Neut. to pH 7.0 (10 mg/1 KMn04) .86 .10
The addition of potassium permanganate to the raw water influent line
ahead of the neutralization stage is recommended in order to consistently
assure oxidation of the manganese and its subsequent removal.
Magnesium removal in the first stage also was highly dependent upon pH
as expected. Very little reduction in raw water magnesium (average value
approximately 18 mg/1) was noted when the first stage pH was set at 7.0.
Operation of the first stage at pH 9.0 to 9.5 resulted in a magnesium reduc-
tion of approximately 50 percent whereas operation at a pH 11.0 to 11.5
resulted in removal of nearly all of the magnesium.
Lime addition to the neutralization process did not contribute an equiva-
lent amount of calcium hardness in the sedimentation basin effluent. Some
calcium (approximately 15 mg/1) was apparently precipitated as calcium
sulfate, as further evidenced by a comparable sulfate loss in the neutraliza-
tion stage. This effect is of interest since it would tend to reduce effluent
sulfate values and this would be particularly desirable for potable water use.
31
-------
Softening Stage
Successful operation of a solids-contact softening unit of the type
employed in this study requires the recycle of settled solids back to the
reaction zone for intimate mixing of previously formed floe with the applied
flow and added chemicals. The manufacturer's instructions called for con-
trolling the slurry concentration at 5 to 10 percent by weight in the bottom
of the basin in order to achieve optimal process operation (11). Except for
a period of about three weeks during the study, however, it was not possible
to maintain the slurry at the desired concentration. The general appearance
of the softener effluent, for the most part, could be characterized as a
turbid water containing a finely divided precipitate. Generally, samples
drawn from various levels and zones within the softening unit failed to show
any differential in the solids concentration which would indicate the desired
solids buildup was occurring. It was possible to build the reaction zone
solids up to the desired levels for brief periods when the pH in the softener
was approximately 11.3 and the temperature of the water being treated was
12°C or higher. It was not possible to obtain good clarification when water
temperatures were below 12°C. Likewise, good clarification was not obtained
at pH 9.6 even when the water temperature was approximately 17°C. The reason
for the good clarification only at the extremely high pH (11.3±) is not under-
stood but it may be due to the virtually complete precipitation of magnesium
as the hydroxide at that pH.
Even when good clarification was being achieved, the municipal water
supply hardness objective of 100 mg CaC03/l was not realized with the desired
consistency. Several possible reasons for this higher-than-expected effluent
hardness exist. Temperature-time relationships are significant in lime-soda
ash softening. The theoretical reaction zone retention time for the softening
unit used in the study was 25 minutes although actual retention times may have
been less than that. No definitive retention time studies were made during
the project, however, which would permit specific conclusions on this point.
Assuming the actual retention time in the reaction zone was approximately 25
minutes, water temperatures should be at least 10°C in order to achieve the
desired effluent hardness of 100. The following table shows the influence of
temperature and time on effluent hardness for given chemical dosages:
TABLE 8. RESIDUAL HARDNESS OBSERVED AT DIFFERENT TEMPERATURES
(mg/1 as
Time (min.)
30
60
90
120
Temperature -
2
124
82
71
75
10
84
71
67
62
OC
20
64
46
46
_ _
32
-------
Water temperatures of less than 10°C would be experienced in the plant
studied commonly during winter months when Kittanning Run is being used as a
source and hence, slow reaction times in the softener would make it impossible
to achieve the desired effluent hardness of 100 mg CaCOa/l at the design flow
of 13,200 cu m/day (3.5 MGD) per unit. Impoundment of this water source would
tend to moderate and stabilize the temperature somewhat and should result in
improved performance of all the treatment units.
Sulfate ion has been shown to have a major effect in slowing the rate of
reaction and formation of calcium carbonate when less than 1000 mg/1 (0.1%)
of preformed calcium carbonate is present (12). The water being treated in
this study contained relatively high sulfates (See Fig. 12) and no bicarbo-
nates. Hence, all the initial hardness to be removed was non-carbonate
hardness (NCH). As indicated above, it was virtually impossible to maintain
the desired level of reaction zone solids in the softener unit, even with
internal sludge recycle, so that the condition necessary to effect optimum
softening with this high sulfate water simply did not exist.
Furthermore, according to Symons (13), formation of complex magnesium
salts may be a problem with waters containing high NCH. These complex salts
are more soluble than magnesium hydroxide; hence, theoretical hardness re-
duction may not be obtainable. The soda ash typically used to remove NCH in
the lime-soda ash process tends to cause formation of basic carbonate complex
salts such as Mg4 (OH)2(C03J2.
700
0.1
0512 5 10 X) 30 40 90 60 TO 80 9096 9899
PERCENT OF TIME ACTUAL VALUE IS EQUAL TO OR LESS THAN GRAPH VALUE
FIGURE 12 RAW WATER SULFATES PROBABILITY PLOT
99.9
33
-------
Under some conditions (temperature, presence of anions, complex salt
formation, etc.) the precipitated salts formed in the softener may remain
in collodial form. This observation may account partially for the observed
difficulty in obtaining good clarification during most of the study. In this
study however, use of alum and polymers did not noticeably improve softener
operation.
Chemical Utilization
Using the weighted mean chemical feed data presented in Table 6, it is
possible to make some observations concerning chemical utilization efficiency
(CUE) for the operating conditions of the study. For the purposes of these
observations, chemical utilization efficiency is defined as:
CUE/o/x = Observed chemical usages , 10Q
v°' Theoretical chemical requirement
a) See definitions 5 and 9, Table 5
b) See definitions 3 and 7, Table 5
Table 9 summarizes the results of the chemical utilization efficiency for
the two phases of the study.
TABLE 9. CHEMICAL UTILIZATION EFFICIENCY
(Percent)
Process Stage
Neutralization
Softening
Phase I
Lime Soda Ash
77.0
79.5 115.
Lime
100.
128.
Phase II
Soda Ash
99.1
The results from Phase I indicate that the neutralization of the influent
water together with the desired pH adjustment for softening only required
approximately 80 percent of the theoretical lime requirement. On the other
hand, the soda ash requirement was approximately 15 percent greater than the
theoretical demand. This observation is particularly significant as it shows
that even with a 15-percent excess of soda ash, it was not possible to achieve
the desired effluent hardness of 100 mg CaC03/l. Possibly, if this excess
were increased, some additional hardness removal could be achieved but it could
increase the chemical costs significantly.
The Phase II data indicates that the observed chemical usage was essential-
ly equal to the theoretical requirements except of the lime utilization in the
softening stage. No explanation of the reason for the considerably higher
lime use in the softening stage was apparent in the data.
34
-------
Figure 13 shows the relationship between softener effluent hardness and
the soda ash dosage for the data collected during the study. Although there
is some scatter in the plotted points, the trend lines shown indicate the
minimum attainable hardness under the conditions of the study was approxi-
mately 120 mg CaC03/l regardless of the soda ash dosage. As indicated
earlier, waters containing appreciable amounts of NCH are difficult to
soften and the data from this study support this observation.
-T, EFFLUENT HARDNESS- mfl./l. CaC03
go 53 8 8 8 S
\
\
\
\
\
^V
\
\.
\
\
\
\
100 200 300 400 500
SODA ASH USAGE- g./cu. m.
RE 13 EFFLUENT HARDNESS AS A FUNCTION OF SODA AS USAGE
35
-------
Figure 14 shows the raw water lime demand required to achieve a given pH.
the additional lime dosage required to raise the pH to 11.3, the optimum point
for best clarification in this study, amount to 21 g/cu m (173 lbs/MG) when
compared to that required to raise the raw water pH to 10.6, a common target
pH for magnesium removal. If compared to a common target pH of 9.6 for cal-
cium removal, this required differential is 37 g/cu m (311 lbs/MG)- It was
impossible to determine whether the high pH required during the study was due
to the raw water characteristics only or was due to a combination of the water
to be treated and the softening unit used. It is felt, however, that it is
primarily related to the high NCH water source, typical of acid mine waters.
200
180
160
140
O I2O
o
o
u_
o
IOO
80
60
40
20
9.6
10.6
11.3
8
PH
IO
12
13
FIGURE 14= RAW WATER LIME DEMAND FOR pH INCREASE
36
-------
The data and curves previously presented reflect operating conditions and
results for the particular blend of waters from Impounding Dam and Kittanning
Run used in the study. Different raw water sources or an appreciable change
in the ratio of I.D. to K.R. would likely change the results obtained. Any
such waters would probably be difficult to soften to low hardness.
Filter Operation
It is unfortunate that it was only possible to obtain filter operating
data for approximately one month during the study. Data collected during this
period generally indicated satisfactory performance with filter runs of 20 to
54 hours being observed (See Table 7). Filtration had little observable
effect on hardness reduction but in several instances, it did significantly
improve manganese removal. It was not possible, with the limited duration
of the filtration study, to determine the long term effects of the poor
clarifier performance on possible calcium carbonate buildup on the filter
media, etc.; nor was it possible to fully evaluate the effect of filter
"seasoning" on the removal of iron and manganese.
One major operating problem developed in the period October 16 to 22
when the filters first were placed in operation during a time when a polymer
(Calgon 253) was being used in an attempt to improve softener clarification.
The filters "fouled" very rapidly with a gelatinous material that coated the
media. The filters were taken out of service and a variety of measures were
taken to restore the media when normal backwash procedures failed to clean
the media. The filters were again placed in operation after cleaning and
operated for approximately one month with no evidence of fouling. It is
believed the filter clogging, therefore, was directly a result of the
polymer addition.
37
-------
SECTION VI
ECONOMIC EVALUATION
CAPITAL INVESTMENT COSTS
The complete water supply system consists of at least three main cost
elements which must be considered in an economic evaluation. They are:
1) the production of raw water, 2) treatment, and 3) transmission of treated
water to storage and distribution. Only the second of these items, treatment
of raw water, will be addressed in this report from the standpoint of capital,
operating and maintenance costs. The type of treatment relative to producing
a finished water of stream release quality is simply lime neutralization,
followed by mixing, aeration and settling. Costs for producing a higher grade
of effluent will be based on a treatment process consisting of iron removal
(neutralization), manganese removal, softening, and, in the case of a munici-
pal supply, chlorination.
Capital investment costs required to provide the unit operations
(concrete tankage, mechanical equipment, instrumentation, etc.) and control
building necessary for the treatment described above, cannot be directly
related to the total cost of the Altoona facility. The principal reason for
this is that the nearly $5 million expenditure for the Altoona plant includes
the capacity to treat 15 mgd through the neutralization stage, in addition to
7.0 mgd in the softening stage. In order to resolve this inconsistency and
include the initial dollar investment for a treatment plant pertinent to our
economic evaluation, the actual costs of the Altoona plant were adjusted to
reflect the capital cost for a 7.0 mgd facility (neutralization through
softening). Conversion to 1975 dollars was accomplished by using a suitable
factor based on construction cost indexes for 1970 (actual plant cost) and
1975 as reported by the Engineering News-Record. Accordingly, the capital
outlay required to provide the treatment levels discussed in this report
would be $1.8 million for the neutralization plant, and $3.8 million for the
neutralization/softening plant. Land and rights-of-way costs are not
included and, as previously mentioned, costs involving water source develop-
ment, transmission mains, storage and distribution systems are not considered.
By way of explanation, with regard to the rather high cost of the neutrali-
zation plant, it should be pointed out that a more sophisticated system
than might be required was provided because of the two-stage nature of the
treatment process and the need for more refined operational control.
Annual payments for these two facilities over twenty-five (25) years at
7% interest amount to $154,440 for the neutralization plant, and $326,040.00
for the neutralization/softening plant - or approximately 1.6
-------
OPERATING AND MAINTENANCE COSTS
Personnel, chemicals and power were the major items of cost considered
under operating expense. Personnel costs were based on the actual manpower
requirements at the Altoona plant. The workforce needed to operate a two-
stage process (neutralization and softening) consisted of a plant supervisor,
four plant operators, four assistant operators and 1/2 chemist. The total
annual cost for personnel was determined to be $135,200.00, or based on water
production, about 1.4<£/cu m (5.2<£/1000 gallons). The personnel costs for
operating a plant strictly for neutralization to meet a stream release dis-
charge quality would not be nearly as much. In our judgment this operation
could be adequately handled by two, or possibly three people at a cost of not
more than $50,000.00/year. In this case the personnel operating expense is
about .5
-------
TABLE 10. SUMMARY OF COST DATAPOWER, CHEMICALS, AND MAINTENANCE
Chemicals
Lime
g/cu m
lb/1000 gal
<£/cu m
-------
TABLE 11. SUMMARY OF TREATMENT COSTS
Neutral!zation Only Neutralization and Softening
stream release quality Hard(120mg/1) Hard(200mg/TT
Capital Investment
-------
SECTION VII
REFERENCES
1. "Public Health Service, Drinking Water Standards, 1962," U.S. Dept. of
Health, Education, and Welfare, Public Health Service, Washington, D.C.
20025.
2. "Safe Drinking Water Act," P.L. 93-523
3. "Industrial Waste Manual," Bureau of Water Quality Management Publication
No. 14, Pa. Dept. of Environmental Resources, 1971.
4. "Methods for Chemical Analysis of Water and Wastes," Environmental Pro-
tection Agency, 1974.
5. "Standard Methods for the Examination of Water and Wastewater," American
Public Health Association, 13th Edition, 1971.
6. "Handbook for Monitoring Industrial Wastewater," U.S. Environmental
Protection Agency, Technology Transfer, Washington D.C., August 1973.
7. "EPA, Report on Coagulant Aids for Water Treatment," Water & Sewage Works
Reference Number 1974, April 30, 1974, pp. R178-R180.
8. Larson, T.E., Lane, R.W., and Neff, C.H., "Stabilization of Magnesium
Hydroxide in the Solids-Contact Process," Journal of American Water
Works Assn, Vol. 51, No. 12, December 1959, pp. 1551-1558.
9. "National Interim Primary Drinking Water Regulations," Federal Register,
Vol. 40, No. 248, Part IV, EPA Water Programs, December 24, 1975, pp.
59566-59588.
10. Penn Environmental Consultants, Inc., Pittsburgh, Pennsylvania, unpub-
lished data.
11. "General Operating Instructions, Walker HC ClariFlow Series,"
No. 6-330-1172, P.L. 6060, Walker Process Equipment.
12. Calise, V.J., Duff, J., and Dvorin, R., "Chemical Reactions in Hot and
Cold Treatment Units," Journal of American Water Works Assn., Vol. 47,
No. 7, July 1955, pp. 665-674.
13. Symons, 6.E., "Water Softening - Part 2 - The Lime-Soda Process, Water &
Sewage Works," Vol. 104, Nov. 1957, pp. 496-503.
42
-------
SECTION VIII
APPENDICES
APPENDIX A. THEORETICAL CONSIDERATIONS : CHEMICAL FEED DATA
Calculation of Neutralization Lime Need
Two general processes will cause a lime demand during the neutralization
stage. The first process is the neutralization of the free acid present.
(1) H2S04 + CaO - *- CaS04 + H20
This reaction shows that one mole of lime will neutralize two moles of free
acid. Therefore at a pH of 3.0, the average pH of the raw water, the amount
of lime required to neutralize the free acid would be 28.0 mg/1 CaO.
The second process that will exert a time demand is the neutralization
of the acid produced by the hydrolysis of the polyvalent metal ions present
in the raw water. The reactions and corresponding lime demand can be
summarized as follows:
(2) Fe2(S04)3 + 3 CaO H2°» 2 Fe (OH)3 + 3CaS04 1 mg/1 Fe+3 requires 1.51
mg/1 CaO
(3) FeS04 + CaO 2 Fe(OH)2 + CaS04 1 mg/1 Fe+2 requires 1.00 mg/1 CaO
(4) Al2(S04)3 + 3CaO H2°>. 2 A1(OH)3 + 3CaS04 1 mg/1 Al+3 requires 3.12
mg/1 CaO
+2
(5) 2 A1(OH)3 + CaO + S04~2 2 2 A102" + CaS04 1 mg/1 Al requires
1.04 mg/1 CaO
(6) MgS04 + CaO H2°... Mg(OH)2 + CaS04 1 mg/1 Mg+2 requires 2.31 mg/1 CaO
(7) MnS04 + CaO_Mn(OH)2 + CaS04 1 mg/1 Mn+2 requires 1.02 mg/1 CaO
Theoretically in order for precipitation to occur the ion product,
[Metal ][OH~], must exceed the solubility product, Ksp, for the compound.
From solubility products, a graph of polyvalent metal ion concentration
at various pH's has been constructed (see Figure A-l).
43
-------
CO
"r
a
to
«I
.o
z
o
UJ
O
o
o
o
8
o
0)
o
00
3 8 ^- to
NOI1V8J.N30NOO
O
CM
UJ
O
a.
oc
44
-------
This graph shows that precipitation of ferric iron will occur completely
when the pH is raised to 4 or above during the neutralization stage. The
precipitation of ferrous hydroxide does not occur until a much higher pH is
attained. However, in the raw water ferric iron predominates, therefore
equation (3) and its corresponding lime demand is insignificant.
Aluminum hydroxide precipitation (4) is essentially complete when the pH
is above 5, however, aluminum is amphoteric. When the hydroxide ion [OH"]
concentration is elevated, the aluminum reacts further (5) and will cause
an additional lime demand. This demand is slight because of insignificant
aluminum concentrations in the sed. basin and can be ignored in all test
periods except for August 12-19.
Theoretically, the precipitation of manganous hydroxide and magnesium
hydroxide in the raw water will occur at pH's of 9.5 and 10.0 respectively
and will be essentially complete at pH's of 10.1 and 10.8.
The neutralization lime feed presented in Table 5, Summary Chemical Feed
Data (see Page 26) was calculated three ways.
1. Theoretical - the theoretical lime requirement is based only on
reactions (1), (2), and (4) assuming these proceed to completion.
2. Needed - the required amount of lime based on observed results.
The difference between the total metal ion concentration in the
raw water and the dissolved metal ion concentration from the
sedimentation basin is multiplied by the appropriate lime demand
Equations (1), (2), (4), (6), and (7) as needed. These demands
are then added to get the total needed lime demand.
3. Observed - amount of lime needed based on calcium increase.
The observed lime feed is lower in most cases than the needed lime feed. We
believe this is due to lime-calcium sulfate reactions with precipitated
aluminum hydroxides as further evidenced by sulfate loss in the neutraliza-
tion stage.
(8) CaO + 3CaS04 + 2A1 (OH)3 _Jj?°__ 3CaS04 . A1203 . CaO . XH20
When this reaction is taken into account, the corrected observed and needed
lime feeds compare more favorably.
Calculation of Softener Lime Need
Lime required on the first stage of softening is related to free carbon
dioxide, carbonate hardness, manganese, Mn+2, and magnesium, Mg+2, contents.
The free carbon dioxide reaction and lime demand is
(9) C02 + CaO-CaC03 1 mg/1 C02 requires 1.27 mg/1 CaO
45
-------
For carbonate hardness the reactions are
(10) Ca+2 + 2HC03 + CaO 2CaC03
(11) Mg+2 + 2HC03 + CaO _ llziL CaC03 + Mg+2 + C03 =
Since carbonate hardness and alkalinity are numerically equal when ex-
pressed as CaC03 the calculation for its lime requirement would be
(12) Alkalinity (Sed. basin in mg/1) x 0.56 = mg/1 CaO
Manganese and magnesium reactions and lime demands would be the same as
in the proceeding section -- equations (6) & (7).
The softener lime feed was calculated three ways.
1. Theoretical - amount of lime needed based on reactions (6) & (7)
2. Needed - the required amount of lime based on observed results.
The lime demand due to the free carbon dioxide (9), carbonate
hardness (12), magnesium (6) and manganese (7) contents.
3. Observed - the lime feed calculated from calcium increase in the
mix box.
Calculation of Softener Soda Ash Need
Soda ash is added to the mix box effluent to remove noncarbonate calcium
hardness. Precipitation of calcium as calcium carbonate occurs according to
the reaction:
(13) Ca+2 + Na2C03 - »-CaC03 + 2Na+
For precipitation to occur, the pH must be about 9.5 or above. The soda ash
demand is 2.64 mg/1 Na,,C03 for each mg/1 Ca+2 precipitated.
If insufficient lime is added in the first stage of softening, the
manganese and magnesium ions in solution will react with the soda ash before
the soda ash can react with the calcium. The equations are:
(14) Mn+2 + 2Na2C03 H2° , Mn(OH)2 + 2HC03 + 4 Na+
(15) Mg+2 + ZNayCOa H20 Mg(OH)2 + 2HCO§ + 4 Na+
The soda ash demands for the above reactions are:
+2
1 mg/1 Mn precipitated requires 3.86 mg/1 Na2C03
+2
1 mg/1 Mg precipitated requires 8.72 mg/1 Na9COo
Cm 0
46
-------
The softener soda ash feed was calculated two ways:
1. Needed - amount of soda ash required for observed results. In most
cases this was calculated by the following formula:
(16) (S.B. - Soft + SLF) x 2.64 = N
Where
S.B. = sed. basin effluent - total Ca value
Soft = softener effluent - dissolved Ca value
SLF = softener lime feed in mg/1 Ca
N = needed soda ash
For 5 test periods; 9/16-19, 9/26-29, 11/18-21, 11/22-24, and 11/25-30
insufficient lime was added in the first stage of softening. Therefore,
equations (14) and (15) with their soda ash demand were used in addition
to the soda ash needed to precipitate the noncarbonate calcium hardness.
2. Observed - the soda ash feed calculated from the sodium increase in
the reaction clarifier.
47
-------
APPENDIX B. SUMMARY OF OPERATIONAL DATA
PERIOD: August 12 - 19, 1974
PROCESS OBJECTIVES: Neutralization Stage pH = 11.0
Softening Stage pH =11.0
Hardness Objective = 100 rng/1
CHEMICAL FEED: Lime, Neutralization stage, kg/cu m = 0.183
Lime, softening stage, kg/cu m = 0
Soda Ash, soft stage, kg/cu m = 0.315
Carbon Dioxide, recarb., kg/cu m = 0.051
REMARKS: No build up of solids in softener reaction zone. Clarification
zone turbid with finely divided precipitate present. Average
operating temperature 21°C. No filter operation.
AVERAGE PERFORMANCE DATA*
Parameter
Flow, mgd.
Flow, cu m/day
pH Units
Acid, tot.
Alk, tot.
Alk, "P"
Ca, tot.
Ca, diss.
Mg, tot.
Mg, diss.
Fe, tot.
Fe, diss.
Mn, tot.
Mn, diss.
Al, tot.
Al, diss.
Na
Hard, (calc.)
S04
Sp. C. umhos/cm^
TSS
TDS
Raw
water
3.5
13,248
3.0
173
0
0
27.7
17.7
17
--
4.5
13.4
1.8
255
273
821
--
--
Sed. basin
effluent
3.5
13,248
11.0
0
105
85
141
132
1.1
0.4
0.8
0.2
0.2
0.1
2.7
2.5
1.8
358
242
929
--
Softener
effluent
3.5
13,248
10.8
0
109
84
41
42
0.4
0.3
0.3
0.1
.05
.01
2.5
2.5
138
119
223
1010
--
--
Recarb.
effluent
3.5
13,248
9.2
0
74
19
33
32
0.4
0.3
0.3
0.1
.06
.01
2.4
1.4
136
87
220
785
--
*Uhless otherwise noted, all results are expressed in mg/1 of the constituent
indicated. Dissolved values were determined on samples filtered through a
borosilicate microfiber glass filter. Acidity, alkalinity, and hardness are
expressed as calcium carbonate equivalent values.
48
-------
PERIOD: September 1 - 15, 1974
PROCESS OBJECTIVES:
Neutralization Stage pH = 9.5
Softening Stage pH = 10.5-11.0
Hardness Objective = 100 mg/1
CHEMICAL FEED:
Lime, neutralization stage, kg/cu m
Lime, softening stage, kg/cu m
Soda Ash, soft stage, kg/cu m
Alum, soft stage, kg/cu m
Carbon Dioxide, recarb., kg/cu m
0.11
0.044
0.213
0.02
0.096 (9/2 & 9/4 only)
REMARKS: No softener reaction zone solids build up. Clarity of softener
effluent poor. Alum feed (20 mg/1) did not help, Recarb. pH
could not be reduced to much under 10.0 with maximum C02 feed.
Average operating temperature 18°C. No filter operation.
AVERAGE PERFORMANCE DATA*
Parameter
Flow, mgd.
Flow, cu m/day
pH units
Acid, tot.
Alk, tot.
Alk, "P"
Ca, tot.
Ca, diss.
Mg, tot.
Mg, diss.
Fe, tot.
Fe, diss.
Mn, tot.
Mn, diss.
Al, tot.
Al , diss.
Na
Hard, (calc.)
S04
Sp. C. umhos/cm2
TSS
TDS
Raw
water
3.5
13,248
3.0
159
--
--
31
18
--
12.4
--
4.7
--
11.4
--
2.1
245
242
823
--
--
Sed. basin
effluent
3.5
13,248
8.6
--
17
2
92
91
8.6
7.5
1.5
0.1
.45
.06
3.0
1.9
2.4
269
211
592
--
--
Softener
effluent
3.5
13,248
10.8
--
80
62
79
50
8.0
0.9
.28
0.1
.08
.01
3.1
2.2
95
141
260
885
--
--
Recarb.
effluent
3.5
13,248
10.0
--
73
39
76
48
1.6
0.9
.17
.1
.06
.01
2.4
1.7
94
133
211
679
--
--
*Unless otherwise noted, all results are expressed in mg/1 of the constituent
indicated. Dissolved values were determined on samples filtered through a
borosilicate microfiber glass filter. Acidity, alkalinity, and hardness are
expressed as calcium carbonate equivalent values.
49
-------
PERIOD: September 16 - 19, 1974
PROCESS OBJECTIVES: Neutralization Stage pH = 7.0
Softening Stage pH = 10.5 - 11.0
Hardness Objective = 100 mg/1
CHEMICAL FEED:
Lime, neutralization stage, kg/cu m = 0.086
Lime, softening stage, kg/cu m = 0.034
Soda Ash, soft stage, kg/cu m = 0.243
REMARKS: Could not build up softener reaction zone solids, poor effluent
clarity. No filter operation. Average operating temperature
18°C. Heavy floe carry over in sedimentation basin effluent.
AVERAGE PERFORMANCE DATA*
Parameter
Flow, mgd.
Flow, cu m/day
pH units
Acid, tot.
Alk, tot.
Alk, "P"
Ca, tot.
Ca, diss.
Mg, tot.
Mg, diss.
Fe, tot.
Fe, diss.
Mn, tot.
Mn, diss.
Al, tot.
Al, diss.
Na
Hard, (calc.)
S04
Sp. C. umhos/cm2
TSS
TDS
Raw
water
3.5
13,248
3.0
190
30
19
--
15
5.0
14
1.9
265
273
897
"*
Sed. basin
effluent
3.5
13,248
7.7
--
16
0
73
69
22
20
2.7
0.1
3.4
2.0
2.1
0.1
3.3
258
240
607
~ ~
Softener
effluent
3.5
13,248
10.2
--
53
28
37
28
14
12
.3
.1
.38
.26
.3
.16
109
119
233
742
--
Recarb.
effluent
3.5
13,248
9.9
--
54
23
37
25
12
12
.3
.1
.42
.16
.2
.13
109
109
231
735
_..
*Unless otherwise noted, all results are expressed in mg/1 of the constituent
indicated. Dissolved values were determined on samples filtered through a
borosilicate microfiber glass filter. Acidity, alkalinity, and hardness are
expressed as calcium carbonate equivalent values.
50
-------
PERIOD: September 20 - 25, 1974
PROCESS OBJECTIVES: Neutralization Stage pH = 7.0
Softening Stage pH =11.4
Hardness Objective = 100 mg/1
CHEMICAL FEED:
Lime, neutralization stage, kg/cu m = 0.086
Lime, softening stage, kg/cu m = 0.064
Soda Ash, soft stage, kg/cu m = 0.231
REMARKS: Heavy, large floe carryover in sedimentation basin effluent.
Softener reaction zone solids were generated at 11.4 pH. Floe
settled well resulting in a clear softener clarification zone.
Average operating temperature 15.6°C. Manganese removal was not
satisfactory.
AVERAGE PERFORMANCE DATA*
Parameters
Flow, mgd
Flow, cu m/day
pH, units
Acid, tot.
Alk. tot.
Alk, "P"
Ca, tot.
Ca, diss.
Mg, tot.
Mg, diss.
Fe, tot.
Fe, diss.
Mn, tot.
Mn, diss.
Al, tot.
Al , diss.
Na
Hard, (calc.)
s°4 ,
Sp. C. umhos/cirr
TSS
TDS
Raw
water
3.5
13,248
2.9
162
--
--
30
--
19
14
4.6
13
2.1
258
267
891
--
Sed. basin
effluent
3.5
13,248
7.5
--
19
--
72
71
20
19
3.7
.2
4.5
3.6
2.9
.2
2.4
260
232
620
--
Softener
effluent
3.5
13,248
11.2
--
67
59
50
50
3
2.6
.2
.1
.16
.30
.2
.3
103
128
236
882
--
Recarb.
effluent
3.5
13,248
9.1
--
55
3
47
40
3
2.8
.2
.1
.16
.26
.2
.1
99
112
223
700
31
*Unless otherwise noted, all results are expressed in mg/1 of the constituent
indicated. Dissolved values were determined on samples filtered through a
borosilicate microfiber glass filter. Acidity, alkalinity, and hardness are
expressed as calcium carbonate equivalent values.
51
-------
PERIOD: September 26 - 30, 1974
PROCESS OBJECTIVES: Neutralization Stage pH = 7.0
Softening Stage pH = 10.5 - 11.0
Hardness Objective = 100 tng/1
CHEMICAL FEED: Lime, neutralization stage, kg/cu m = 0.102
Lime, softening stage, kg/cu m = 0.043
Soda Ash, soft stage, kg/cu m =0.22
REMARKS: Softener effluent poor in clarity. Manganese too high.
Average operating temperature 15.7°C.
AVERAGE PERFORMANCE DATA*
Parameter
Flow, mgd.
Flow, cu m/day
pH Units
Acid, tot.
Alk, tot.
Alk, "P"
Ca, tot.
Ca, diss.
Mg, tot.
Mg, diss.
Fe, tot.
Fe, diss.
Mn, tot.
Mn, diss.
Al, tot.
Al , diss.
Na
Hard, (calc.)
s°4
Sp. C umhos/cnr
TSS
TDS
Raw
water
3.5
13,248
3.1
176
--
30
--
20
19
5.0
14
--
2.1
277
289
974
Sed. basin
effluent
3.5
13,248
6.7
--
25
73
73
23
22
3.7
0.1
5.2
4.2
2.9
0.2
2.4
278
235
640
--
Softener
effluent
3.5
13,248
10.6
--
41
31
29
15
14
0.5
0.1
.23
.28
.4
.3
98
112
240
729
Recarb.
effluent
3.5
13,248
8.0
--
60
28
30
10
10
.6
.1
.3
.4
.5
.3
99
no
229
735
*Unless otherwise noted, all results are expressed in mg/1 of the constituent
indicated. Dissolved values were determined on samples filtered through a
borosilicate microfiber glass filter. Acidity, alkalinity, and hardness are
expressed as calcium carbonate equivalent values.
52
-------
PERIOD: October 1 - 4, 1974
PROCESS OBJECTIVES: Neutralization Stage pH = 7.0
Softening Stage pH = 11.4
Hardness objective = 100 mg/1
Controlling level in aeration tank and regulating aerator
operation (2 hrs/shift) to reduce floe breakup and im-
prove solids removal in sedmintation basin.
CHEMICAL FEED:
Lime, neutralization stage, kg/cu m = 0.102
Lime, softening stage, kg/cu m = 0.061
Soda Ash, soft stage, kg/cu m = 0.234
REMARKS: Excellent softener operation, 14% by volume settleable reaction zone
solids (5 min. test). No significant improvement in sed. basin
solids removal. Average operating temperature 12.1°C in softener.
AVERAGE PERFORMANCE DATA*
Parameter
Flow, mgd
Flow, cu m/day
pH units
Acid, tot.
Alk, tot.
Alk, "P"
Ca, tot.
Ca, diss.
Mg, tot.
Mg, diss.
Fe, tot.
Fe, diss.
Mn, tot.
Mn, diss.
Al, tot.
Al , diss.
Na
Hard, (calc.)
S04
Sp. C. umhos/cm^
TSS
TDS
Raw
water
3.5
13,248
2.9
178
--
31
19
15
--
4.8
--
13
2.2
267
278
948
--
Sed. basin
effluent
3.5
13,248
7.0
--
25
--
78
77
21
19
4.0
0.1
4.9
4.0
3.0
0.1
2.5
277
231
610
Recarb.
effluent
3.5
13,248
11.4
58
--
44
41
2.0
2.8
0.1
0.1
.08
--
0.1
0.1
104
112
228
840
4
*Unless otherwise noted, all results are expressed in mg/1 of the constituent
indicated. Dissolved values were determined on samples filtered through a
borosilicate microfiber glass filter. Acidity, alkalinity, and hardness are
expressed as calcium carbonate equivalent values.
53
-------
PERIOD: October 5 - 7, 1974
PROCESS OBJECTIVE:
CHEMICAL FEED:
REMARKS:
Neutralization Stage pH = 7.0
Softening Stage pH = 11.5
Hardness Objective = 100 mg/1
Coagulant aid addition (1 mg/1) to sed. basin to
improve solids removal
Lime, Neutralization stage, kg/cu m = 0.113
Lime, softening stage, kg/cu m = Q.053
Soda Ash, soft stage, kg/cu m =0.217
Coag. Aid, sed. basin, kg/cu m = 0.001
Excellent softener operation, 13% (by volume) settleable reaction
zone solids. Coagulant aid improved sed. basin solids removal.
Average operating temperature 12.5°C.
AVERAGE PERFORMANCE DATA*
Parameter
Flow, mgd.
Flow, cu m/day
pH units
Acid, tot.
Alk, tot.
Alk, "P"
Ca, tot.
Ca, diss.
Mg, tot.
Mg, diss.
Fe, tot.
Fe, diss.
Mn, tot.
Mn, diss.
Al, tot.
Al , diss.
Na
Hard, (calc.)
S04
Sp. C. umhos/cm2
TSS
TDS
Raw
water
3.5
13,248
2.9
186
--
32
20
17
--
5.0
13
2.0
276
293
963
Sed. basin
effluent
3.5
13,248
7.0
--
14
--
78
78
20
18
1.6
0.1
3.7
3.3
1.7
0.1
2.5
272
230
595
8
--
Recarb.
effluent
3.5
13,248
11.4
--
84
80
52
48
1.8
2.1
0.1
0.1
.04
0.1
0.1
97
127
225
990
3
--
*Unless otherwise noted, all results are expressed in mg/1 of the constituent
indicated. Dissolved values were determined on samples filtered through a
borosilicate microfiber glass filter. Acidity, alkalinity, and hardness are
expressed as calcium carbonate equivalent values.
54
-------
PERIOD: October 8 - 10, 1974
PROCESS OBJECTIVES: Neutralization Stage pH = 7.0
Softening Stage pH = 11.3
Hardness Objective = 100 mg/1
Feeding 6.3 mg/1 potassium permanganate to softener for
manganese oxidation.
CHEMICAL FEED: Lime, Neutralization stage, kg/cu m = 0.108
Lime, softening stage, kg/cu m = 0.053
Soda Ash, soft stage, kg/cu m = 0.204
Potass. Perm., soft stage, kg/cu m = 0.006
REMARKS: Good softener operation, but unable to reduce manganese to
acceptable level. Average operating temperature 12.5°C.
12% by volume settleable reaction zone solids.
AVERAGE PERFORMANCE DATA*
Parameter
Flow, mgd.
Flow, cu m/day
pH units
Acid, tot.
Alk, tot.
Alk, "P"
Ca, tot.
Ca, diss.
Mg, tot.
Mg, diss.
Fe, tot.
Fe, diss.
Mn, tot.
Mn, diss.
Als tot.
Al , diss.
Na
Hard, (calc)
S04
Sp. C. umhos/cm2
TSS
TDS
Raw
water
3.5
13,248
3.0
179
--
31
20
--
15
--
48
--
14
--
2.3
268
277
902
--
Sed. basin
effluent
3.5
13,248
7.3
--
14
72
70
19
18
3.0
0.2
4.2
3.9
2.3
0.1
2.5
257
212
550
12
Recarb.
effluent
3.5
13,248
11.3
__
54
41
51
47
2.0
3.1
0.1
0.1
0.27
0.27
0.2
0.2
88
123
199
773
5
--
*Unless otherwise noted, all results are expressed in mg/1 of the constituent
indicated. Dissolved values were determined on samples filtered through a
borosilicate microfiber glass filter. Acidity, alkalinity, and hardness are
expressed as calcium carbonate equivalent values.
55
-------
PERIOD: October 12 - 16, 1974
PROCESS OBJECTIVES: Neutralization Stage pH = 9.5
Softening Stage pH = 11.3
Hardness Objective = 100 mg/1
CHEMICAL FEED: Lime, neutralization stage, kg/cu m = 0.119
Lime, softening stage, kg/cu m = 0.023
Soda Ash, soft stage, kg/cu m = 0.222
REMARKS: Poor softener operation, no reaction zone solids. Average operating
temperature 13.6°C. (Note: lower magnesium and manganese levels in
sed. basin effluent)
AVERAGE PERFORMANCE DATA*
Parameter
Flow, mgd.
Flow, cu m/day
pH units
Acid, tot.
Alk, tot.
Alk, "P"
Ca, tot.
Ca, diss.
Mg, tot.
Mg, diss.
Fe, tot.
Fe, diss.
Mn, tot.
Mn, diss.
Al, tot.
Al , diss.
Na
Hard, (calc.)
S04
Sp. C umhos/cirr
TSS
TDS
Raw
water
3.5
13,248
3.1
160
31
--
17
13
--
4.5
--
13
2.1
244
247
794
--
Sed. basin
effluent
3.5
13,248
9.7
--
18
--
89
89
7.5
6.8
1.5
0.1
.29
.08
2.9
1.2
2.4
259
198
546
--
--
Recarb.
effluent
3.5
13,248
11.3
--
67
46
60
45
2.6
2.0
0.1
0.1
.09
.01
1.8
1.0
99
126
198
799
49
*Unless otherwise noted, all results are expressed in mg/1 of the constituent
indicated. Dissolved values were determined on samples filtered through a
borosilicate microfiber glass filter. Acidity, alkalinity, and hardness are
expressed as calcium carbonate equivalent values.
56
-------
PERIOD: October 17 - 22, 1974
PROCESS OBJECTIVES: Neutralization Stage pH = 9.5
Softening Stage pH =11.4
Hardness Objective = 200 mg/1
CHEMICAL FEED: Lime, neutralization stage, kg/cu m = 0.087
Lime, softening stage, kg/cu m = 0.027
Soda Ash, soft stage, kg/cu m = 0.137
Coag. Aid, soft stage, kg.cu m =0.001
REMARKS: No reaction zone solids build up in softener, effluent clarity
poor. Average operating temperature 10°C. No improvement with the
use of coagulant aid.
AVERAGE PERFORMANCE DATA*
Parameter
Flow, mgd.
Flow, cu m/day
pH units
Acid, tot.
Alk, tot.
Alk, "P"
Ca, tot.
Ca, diss.
Mg, tot.
Mg, diss.
Fe, tot.
Fe, diss.
Mn, tot.
Mn, diss.
Al, tot.
Al, diss.
Na
Hard, (calc.)
S04
Sp. C. umhos/cm2
TSS
TDS
Raw
water
3.5
13,248
3.1
160
--
--
30
17
--
11.6
--
4.2
--
10.5
--
2.4
226
224
746
Sed. basin
effluent
3.5
13,248
9.3
15
--
82
82
14
11.3
2.2
0.1
.69
.10
2.8
1.0
2.6
256
206
555
--
Recarb.
effluent
3.5
13,248
11.1
--
70
56
90
76
3.9
3.7
0.1
0.1
.04
.02
0.2
0.2
62
207
207
834
39
__
*Unless otherwise noted, all results are expressed in mg/1 of the constituent
indicated. Dissolved values were determined on samples filtered through a
borosilicate microfiber glass filter. Acidity, alkalinity, and hardness are
expressed as calcium carbonate equivalent values.
57
-------
PERIOD: October 28 - November 11, 1974
PROCESS OBJECTIVES: Neutralization Stage pH = 8.5 - 9.0
Softening Stage pH =11.3
Hardness Objective = 200 mg/1
CHEMICAL FEED:
Lime, neutralization stage, kg/cu m = 0.072
Lime, softening stage, kg/cu m = 0.036
Soda Ash, soft stage, kg/cu m =0.112
REMARKS: Average operating temperature (softener) 11°C. Flow to filters
limited to 2.0 mgd applied to one-fourth of the filter capacity.
In this way, performance could be evaluated at the hydraulic design
loading.
AVERAGE PERFORMANCE DATA*
Parameters
Flow, mgd
Flow, cu m/day
pH, units
Acid, tot.
Alk, tot.
Alk, "P"
Ca, tot.
Ca, diss.
Mg, tot.
Mg, diss.
Fe, tot.
Fe, diss.
Mn, tot.
Mn, diss.
Al, tot.
Al , diss.
Na
Hard, (calc.)
S04
Sp. C umhos/cm^
TSS
TDS
Raw
water
3.5
13,248
3.0
143
--
31
--
16
--
13
__
4.3
10.4
__
2.4
228
226
774
--
Sed. basin
effluent
3.5
13,248
7.2
--
15
--
76
75
15
15
2.1
0.1
1.4
0.8
2.2
0.6
2.6
253
215
572
--
-
Mix Box
3.5
13,248
10.7
--
90
35
112
14
1.9
--
1.19
--
1.9
2.8
357
211
630
--
Softener
effluent
3.5
13,248
10.7
--
39
33
73
65
4.3
4.3
0.1
0.1
.08
.08
0.1
.07
51
182
211
670
8
--
Filter
effluent
2.0
7,570
7.9
--
53
65
3.8
0.1
--
.03
0.1
--
46
176
197
623
--
--
*Unless otherwise noted, all results are expressed in mg/1 of the constituent
indicated. Dissolved values were determined on samples filtered through a
borosilicate microfiber glass filter. Acidity, alkalinity, and hardness are
expressed as calcium carbonate equivalent values.
58
-------
PERIOD: November 11 - 17, 1974 (6 days, 11/21/75 omitted, see remarks below)
PROCESS OBJECTIVES: Neutralization Stage pH = 8.5 - 9.0
Softening Stage pH =11.3
Hardness Objective = 200 mg/1
Demanganization by feeding potassium permanganate
(TO IRQ/I) to the influent raw water line.
CHEMICAL FEED: Lime, neutralization stage, kg/cu m = 0.088
Lime, softening stage, kg/cu m = 0.026
Soda Ash, softening stage, kg/cu m = 0.084
Potass, perm., influ. line, kg/cu m = 0.041
REMARKS: Heavy rainfall occurred on November 12 causing a 5.0 mgd flow
through the plant for a short period. This hydraulic overload
upset the softener operation. Average softener operating tempera-
ture 6.4°C. Filter runs were 54 hours.
AVERAGE PERFORMANCE DATA*
Parameter
Raw Sed. Basin Mi R Softener Recarb. Filter
water effluent effluent effluent effluent
Flow, mgd
Flow, cu m /day
pH, units
Acid, tot.
Alk, tot.
Alk, "P"
Ca, tot.
Ca, diss.
Mg, tot.
Mg, diss.
Fe, tot.
Fe, diss.
Mn, tot.
Mn, diss.
Al, tot.
Al, diss.
Na
Hard. (Calc.)
S04
Sp. C umhos/cm2
TSS
TDS
3.5
13,248
3.1
103
--
28
--
14
--
6
--
3.4
8.7
--
3.3
194
183
638
--
3.5
13,248
7.0
14
__
80
80
16
15
1.8
0.2
.74
.16
1.9
0.5
3.2
264
233
627
3.5
13,248
10.5
80
20
m
16
1.8
.67
--
1.9
--
3.2
356
233
702
--
3.5
13,248
10.5
--
35
27
80
77
6.6
6.6
0.2
0.1
.08
.03
0.2
0.1
39
221
234
714
42
3.5
13,248
8.4
--
49
--
74
--
6.8
0.2
--
.06
--
0.2
41
216
225
691
""
2.0
7,570
8.1
46
--
74
--
6.6
--
0.1
--
.02
0.1
--
40
214
225
683
--
*Unless otherwise noted, all results are expressed in mg/1 of the constituent
indicated. Dissolved values were determined on samples filtered through a
borosilicate microfiber glass filter. Acidity, alkalinity, and hardness are
expressed as calcium carbonate equivalent values.
59
-------
PERIOD: November 18-21, 1974 (4 days)
PROCESS OBJECTIVES: Neutralization Stage pH = 8.5 - 9.0
Softening Stage pH =10.5
Hardness Objective = 200 mg/1
CHEMICAL FEED: Lime, neutralization stage, kg/cu m = 0.11
Lime, softening stage, kg/cu m = 0.016
Soda Ash, soft stage, kg/cu m = 0.10
Potass, perm., influ. line kg/cu m =0.01
REMARKS: Softener clarification poor with brown floe carry over.
Average operating temperature 5.3°C. Filter runs 30 hours.
AVERAGE PERFORMANCE DATA*
Dav,,mQtQ₯, Raw Sed. Basin M. . Softener Recarb. Filter
parameter water effluent nix. box effluent effluent effluent
Flow, mgd
Flow, cu m/day
pH, units
Acid, tot.
Alk, tot.
Alk, "P"
Ca, tot.
Ca, diss.
Mg, tot.
Mg, diss.
Fe, tot.
Fe, diss.
Mn, tot.
Mn, diss.
Al.tot.
Al, diss.
Na
Hard, (calc.)
S04
Sp. C. umhos/cm^
TSS
TDS
3.5
13,248
2.8
193
--
--
30
__
18
15
4.6
--
15
--
2.7
270
275
919
3.5
13,248
7.8
14
--
92
85
16
16
3.4
0.1
.98
.04
2.6
0.6
3.1
284
245
610
--
--
3.5
13,248 13
9.4
--
46
3
96
--
17
2.9
.86
2.3
--
4.7
329
247
616
--
--
3.5
,248
9.2
--
24
2
70
64
16
13
1.8
0.1
.48
.03
1.2
0.3
46
218
244
645
--
__
3.5
13,248
7.7
--
41
--
64
--
13
1.2
0.4
0.8
--
46
223
229
680
26
--
2.0
7,570
6.9
--
43
--
63
--
13
--
0.3
--
.04
0.1
--
46
212
240
675
460
*Unless otherwise noted, all results are expressed in mg/1 of the constituent
indicated. Dissolved values were determined on samples filtered through a
borosilicate microfiber glass filter. Acidity, alkalinity, and hardness are
expressed as calcium carbonate equivalent values.
60
-------
PERIOD: November 22 - 24, 1974 (3 days)
PROCESS OBJECTIVES: Neutralization Stage pH = 8.5 - 9.0
Softening Stage, pH = 10.5
Hardness Objective = 200 mg/1
CHEMICAL FEED: Lime, neutralization stage, kg/cu m = 0.104
Lime, softening stage, kg/cu m =0.018
Soda Ash, soft stage, kg/cu m = 0.166
Carbon dioxide, recarb., kg/cu m = 0.044
REMARKS: Softener clarification poor. Average operating temperature 5°C
Filter runs 20 hours.
AVERAGE PERFORMANCE DATA*
Parameter
Flow, mgd
Flow, cu m/day
pH, units
Acid, tot.
Alk, tot.
Alk, "P"
Ca, tot.
Ca, diss.
Mg, tot.
Mg, diss.
Fe, tot.
Fe, diss.
Mn, tot.
Mn, diss.
Al, tot.
Al, diss.
Na
Hard, (calc.)
S04
Sp. C. umhos/cm2
TSS
TDS
Raw
water
3.5
13,248
3.0
175
--
29
--
18
--
18
--
4.4
15
--
2.9
269
260
893
--
~
Sed. basin
effluent
3.5
13,248
7.0
--
14
94
86
16
16
3.5
0.1
1.5
.36
2.7
0.4
3.6
287
244
613
--
--
Mix box
3.5
13,248
9.5
--
38
3
88
--
18
--
3.0
1.2
--
2.5
--
315
245
617
--
-
Softener
effluent
3.5
13,248
9.7
--
103
9
67
43
13
12
1.5
0.1
.46
.04
1.2
0.4
75
159
239
697
--
Recarb.
effluent
3.5
13,248
8.3
--
105
0
59
12
--
1.3
--
.52
--
1.0
--
73
--
233
767
46
~
Filter
effluent
2.0
7,570
7.9
--
84
--
45
--
12
--
0.2
.04
--
0.1
--
73
165
231
757
--
747
*Unless otherwise noted, all results are expressed in mg/1 of the constituent
indicated. Dissolved values were determined on samples filtered through a
borosilicate microfiber glass filter. Acidity, alkalinity, and hardness are
expressed as calcium carbonate equivalent values.
61
-------
PERIOD: November 25 - 30, 1974 (6 days)
PROCESS OBJECTIVES: Neutralization Stage pH = 8.5-9.0
Softening Stage pH = 10.5
Hardness Objective = 106 mg/1
CHEMICAL FEED: Lime, Neutralization stage, kg/cu m = 0.098
Lime, softening stage, kg/cu m = 0.037
Soda Ash, soft stage, kg/cu m = 0.33
Carbon dioxide, recarb., kg/cu m = 0.075 (11/25 & 11/26
only)
REMARKS: Poor softener clarification - 20 hour filter runs. Average
operating temperature 2.3°C.
AVERAGE PERFORMANCE DATA*
Parameter
Flow, mgd
Flow, cu m/day
pH, units
Acid, tot.
Alk, tot.
Alk, "P"
Ca, tot.
Ca, diss.
Mg, tot.
Mg, diss.
Fe, tot.
Fe, diss.
Mn, tot.
Mn, diss.
Al, tot.
Al , diss.
Na
Hard, (calc.)
S04
Sp. C umhos/cm2
TSS
TDS
Raw
water
3.5
13,248
2.9
173
--
27
17
24
4.2
15
2.3
272
262
890
Sed. basin
effluent
3.5
13,248
7.4
24
94
88
18
18
3.2
0.1
2.2
1.2
2.7
0.5
2.8
297
257
646
Mix box
3.5
13,248
9.4
91
6
104
--
18
2.9
--
2.0
--
2.4
--
2.4
359
254
734
Softener
effluent
3.5
13,248
10.4
153
43
44
28
9.9
9.4
0.7
0.1
.44
.08
0.5
0.2
146
112
254
941
Recarb.
effluent
3.5
13,248
8.2
--
177
0
38
--
9.8
0.7
--
.34
0.4
137
139
234
917
53
Filter
effluent
2.0
7,470
8.4
--
160
2
25
--
9.3
--
0.1
--
.08
--
0.1
--
141
103
235
867
*Unless otherwise noted, all results are expressed in mg/1 of the constituent
indicated. Dissolved values were determined on samples filtered through a
borosilicate microfiber glass filter. Acidity, alkalinity, and hardness are
expressed as calcium carbonate equivalent values.
62
-------
PERIOD: December 3 - 8, 1974 (6 days)
PROCESS OBJECTIVES: Neutralization Stage pH = 7.0-7.5
Softening Stage pH = 11.3
Hardness Objective = 100 mg/1
CHEMICAL FEED: Lime, Neutralization stage, kg/cu m = 0.098
Lime, softening stage, kg/cu m = 0.053
Soda Ash, soft stage, kg/cu m = 0.317
Carbon dioxide, recarb., kg/cu m = 0.18 (12/5 - 12/8)
REMARKS: Poor softener clarification. Filter runs 20 hours. Average
operating temperature 1.5°C.
AVERAGE PERFORMANCE DATA*
Parameter
Flow, mgd
Flow cu m/day
pH Units
Acid, tot.
Alk., tot.
Alk., "P"
Ca, totl.
Ca, diss.
Mg, tot.
Mg, diss.
Fe, tot.
Fe, diss.
Mn, tot.
Mn, diss.
Al, tot.
Al, diss.
Na
Hard.(calc.)
S04
Sp.C umhos/cm2
TSS
TDS
Raw
water
3.5
13,248
2.9
190
26
--
16
26
4.0
16
2.0
268
268
915
--
Sed. basin
effluent
3.5
13,248
7.1
24
96
90
19
18
3.7
0.2
7.7
4.8
2.4
0.1
2.0
312
274
682
--
--
Mix box
3.5
13,248
10.2
--
106
18
130
16
2.4
--
7.2
1.9
2.7
426
270
755
--
Softener
ef f 1 uent
3.5
13,248
10.6
--
175
34
64
40
7.6
5.6
1.1
0.1
.98
.37
0.2
0.1
140
133
271
945
--
--
Recarb.
effluent
3.5
13,248
7.8
96
0
62
--
6.7
0.5
.33
0.2
Ill
258
853
41
--
Filter
effluent
2.0
7,570
7.6
--
96
54
7.3
--
0.1
.19
0.1
116
--
292
922
--
*Unless otherwise noted, all results are expressed in mg/1 of the constituent
indicated. Dissolved values were determined on samples filtered through a
borosilicate microfiber glass filter. Acidity, alkalinity, and hardness are
expressed as calcium carbonate equivalent values.
63
-------
PERIOD: June 16-26, 1975 (10 days)
PROCESS OBJECTIVES: Neutralization Stage pH = 9.0
Softening Stage pH =9.6
Hardness Objective = 100 mg/1
Recarbonation effluent pH = 8.5
CHEMICAL FEED: Lime Neutralization stage, kg/cu m = 0.138
Lime, softening stage, kg/cu m = 0
Soda Ash, soft, stage, kg/cu m = 0.334
Coag. Aid., Sed. Basin, kg/cu m = 0.0004
Carbon Dioxide, recarb., kg/cu m = 0.029
REMARKS: Temperature ranged in softener from 12°-20"C (Avg. 17°C)
Clarification zone was hazy/turbid with finely divided precipitate
in suspension. Hardness objective (100 mg/1) was not met.
AVERAGE PERFORMANCE DATA*
Parameter
Flow, mgd
Flow cu m/day
pH, units
Acid, tot.
Alk., tot.
Alk, "P"
Ca, tot.
Ca, diss.
Mg, tot.
Mg, diss.
Fe, tot.
Fe, diss.
Mn, tot.
Mn, diss.
Al , tot.
Al , diss.
Na
Hard. (calc. )
S0d
LL f\
Sp. C umhos/crrr-
TSS
TDS
Raw
water
3.5
13,248
2.1
191
--
28
20
--
23
4.9
--
17
--
2.9
252
339
807
~
Sed. basin
effluent
3.5
13,248
7.5
--
-1
10
113
111
16
16
1.4
.07
1.8
0.9
2.5
1.5
1.6
364
322
618
--
Softener
effluent
3.5
13,248
9.4
53
9
40
32
12
11
.29
.03
.43
.04
1.2
.7
138
127
315
814
--
Recarb.
effluent
3.5
13,248
8.7
82
3
39
31
12
11
0.3
.06
.32
.07
1.2
0.5
136
124
305
825
--
573
*Unless otherwise noted, all results are expressed in mg/1 of the constituent
indicated. Dissolved values were determined on samples filtered through a
borosilicate microfiber glass filter. Acidity, alkalinity, and hardness are
expressed as calcium carbonate equivalent values.
64
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1. REPORT NO.
EPA-600/2-77-090
3. RECIPIENT'S ACCESSIOf*NO.
4. TITLE AND SUBTITLE
SODA ASH TREATMENT OF NEUTRALIZED MINE DRAINAGE
5. REPORT DATE
May 1977 issuing date
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
8. PERFORMING ORGANIZATION REPORT NO.
David A. Long, James L, Butler, & Michael J. Lenkevich
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Commonwealth of Pennsylvania*
Department of Environmental Resources
Harrisburg, Pennsylvania 17102
10. PROGRAM ELEMENT NO.
TRBfil 0
11. CONTRACT/GRANT NO.
1^010 ELB
12. SPONSORING AGENCY NAME AND ADDRESS
Industrial Environmental Research Laboratory- Gin., OH
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, Ohio U5268
13. TYPE OF REPORT AND PERIOD COVERED
Final 6/70 - 12/75
14. SPONSORING AGENCY CODE
EPA/600/12
15. SUPPLEMENTARY NOTES
*Research work was performed and authors employed by Gwin, Dobson , and Foreman, Inc.,
Altoona, Pennsylvania 16603
16. ABSTRACT
Utilization of acid mine drainage (AMD) streams as a source of potable and indus-
trial water has become a major goal of several proposed AMD treatment schemes. From
among the various schemes available, the lime neutralization/soda ash softening pro-
cess was selected for use at Altoona, Pennsylvania.
The treatment plant, as constructed, has the capability of treating waters from
Kittanning Run (acid mine polluted) alone or in combination with waters from other
city sources to achieve: (l) neutralization and iron removal to levels satisfactory
for stream release, (2) softening to approximately 100 mg/1 CaCO~ hardness for munic-
ipal use, and (3) softening to a hardness of 200 mg/1 CaCO or higher to meet indus-
trial use requirements.
The objective of this study was to evaluate the technical and economic feasibility
of softening neutralized AMD waters by means of the cold lime/soda ash process. The
study was conducted full-scale at the Altoona Treatment Plant located near the
Horseshoe Curve area of Altoona, Pennsylvania. Unit processes employed at the plant
consisted of lime neutralization, aeration, settling, soda ash softening, recarbon-
ation, and filtration.
The results generally indicated that the desired quality could be achieved.
Effluent quality of 100 mg/1 hardness cost 10 cents/cu m (37 cents/1000 gal); treat-
ment-, t.o PPn Tng/1 nngf. Q opnt.H/r-ii m ( ^ pp-ntH/IPOD gRl 1 .
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.IDENTIFIERS/OPEN ENDED TERMS C. COS AT I Field/Group
Calcium hydroxides
Coal mines
Drainage
Neutralizing
pH control
Softening
Sodium carbonates
Acid mine drainage
Pennsylvania
13B
18. DISTRIBUTION STATEMENT
Release to public
19. SECURITY CLASS (This Report)
TInr-1 a.Rgi f i prl
21. NO. OF PAGES
73
20. SECURITY CLASS (Thispage)
T In r> 1 QQQ'1 "Pi Q rl
22. PRICE
EPA Form 2220-1 (9-73)
65
ftUS GOVERNMENT PRINTING OFFICE 1977757-056/6464
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