WATER POLLUTION CONTROL RESEARCH SERIES • 14010 DM 05/71
Rotary Precoat Filtration
Of Sludge From
Acid Mine Drainage Neutralization
ENVIRONMENTAL PROTECTION AGENCY • WATER QUALITY OFFI
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MATER POLLUTION CONTROL RESEARCH SERIES
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Rotary P re coat Filtration
Of Sludge From
Acid Mine Drainage Neutralization
Johns-Manville Products Corporation
Research & Engineering Center
Manville, New Jersey 08835
for the
Commonwealth of Pennsylvania
Coal Research Board
and
Water Quality Office
Environmental Protection Agency
Program Number
Grant 14010 DII
May, 1971
For sale by the Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402 - Price $1.25
Stock Number 5501-0096
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EPA Review Notice
This report has been reviewed by the Water Quality
Office, Environmental Protection Agency and approved
for publication. Approval does not signify that the
contents necessarily reflect the views and policies
of the Water Quality Office, Environmental Protection
Agency, nor does mention of trade names or commercial
products constitute endorsement or recommendation for
use.
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ABSTRACT
Rotary vacuum precoat filtration was investigated as a means for de-
watering sludge produced by the neutralization of mine drainage at
four locations in Pennsylvania during 1969 and 1970.
The process used at these sites consisted of neutralization, aeration,
sedimentation, and filtration. The alkalies investigated were lime-
stone, limestone with hydrated lime, calcined magnesite, partially and
fully calcined dolomite, and hydrated lime. Filter aids tested included
HYFLO © SUPER-CEL ® , CELITE ® 501, CELITE 503, and CELITE'545. Work
at the first three locations indicated that limestone and hydrated lime
were the preferred alkalies and that CELITE 501 was the preferred filter
aid.
A more extensive program was conducted at the fourth site. A 27 run
factorial experiment was conducted investigating the effect of flow rate,
limestone feed level, aeration level, and sludge recirculation on equip-
ment operation and on process cost. The significant variables affecting
process coat were found to be sludge solids content, the filtration rate,
and sludge recirculation. A detailed economic analysis of the process is
included in the report.
This report was submitted in fulfillment of Project No. 14010 DII under
the sponsorship of the Water Quality Office, Environmental Protection
Agency and the Commonwealth of Pennsylvania Coal Research Board.
Key Words: Mine Drainage, Neutralization, Lime, Limestone, Sludge,
Rotary Precoat Filtration, Dewater, Economics, Pennsyl-
vania.
Registered trademarks for Johns-Manville Products Corporation
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TABLE OF CONTENTS
Page
ABSTRACT .........................................
TABLE OF CONTENTS ................................
LIST OF FIGURES ..................................
LIST OF TABLES ................................... v
Section
I CONCLUSIONS .............................. . ....... 1
II RECOMMENDATIONS .................................. 3
III INTRODUCTION ..................................... 5
IV DISCUSSION ....................................... 15
V ACKNOWLEDGMENTS .................................. 19
VI REFERENCES ....................................... 21
VII APPENDICES
-A Dark Water Mine, St. Clair, Pennsylvania .... 23
-B Rushton Mining Company, Osceola Mills,
Pennsylvania ................................ 33
-C Bennett Branch, Hollywood, Pennsylvania ..... 47
-D Proctor No. 2, Hollywood, Pennsylvania ...... 57
-E Economic Analysis ........................... Ill
ii
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LIST OF FIGURES
Page
FIGURE 1: Rotary Vacuum Precoat Filter - Side View 7
FIGURE 2: Rotary Vacuum Precoat Filter Knife Cut 8
FIGURE 3: Tube Mill 9
FIGURE A: Original System Flow Diagram 11
FIGURE 5: Proctor No. 2 System Flow Diagram 12
FIGURE 6: Precoat Test Leaf 13
FIGURE 7: Overflow Turbidity as a Function of Time 27
FIGURE 8: Knife Advance Curve - CELITE 501 29
FIGURE 9: Knife Advance Curve - CELITE 545 30
FIGURE 10: Knife Advance Curve - CELITE 503 31
FIGURE 11: Knife Advance Curve - Lime and Magnesite with
Aeration 37
FIGURE 12: Knife Advance Curve - Lime and Magnesite without
Aeration 38
FIGURE 13: Knife Advance Curve - Limestone and Magnesite ... 39
FIGURE 14: Knife Advance Curve - Limestone and Lime 40
FIGURE 15: Flow Rate - 24 Hour Run - Limestone and
Magnesite 43
FIGURE 16: Flow Rate - 24 Hour Run - Limestone with
Aeration 44
FIGURE 17: Knife Advance Curve - Limestone and Magnesite ... 51
FIGURE 18: Knife Advance Curve - Limestone Slurry and Lime . 52
FIGURE 19: Knife Advance Curve - Limestone Dust and Fully
Calcined Dolomite 53
FIGURE 20: Knife Advance Curve - Limestone Slurry and
Partially Calcined Dolomite 54
iii
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LIST OF FIGURES
FIGURE 21:
FIGURE 22:
FIGURE 23:
FIGURE 24:
FIGURE 25:
FIGURE 26:
FIGURE 27:
FIGURE 28:
FIGURE 29:
FIGURE 30:
FIGURE 31:
Filtration Performance of Limestone Slurry
and Rock Dust
pH vs Limestone Addition
Filtered Free Mineral Acidity vs Limestone
Addition <
Filtration Characteristics - Level 19 Sludge ..,
Filtration Characteristics - Level 19 Sludge ..,
Filtration Characteristics - Level 23 Sludge ..,
Filtration Characteristics - Level 23 Sludge ..,
Effect of Sludge Solids on Filtration Rate
Effect of Sludge Solids on Filter Station Cost ,
Thickener Area Requirement - Level 23 Sludge ..,
Effect of Sludge Solids on Thickener and Filter
Station Cost
FIGURE 32: Effect of Plant Size on Operating Cost
Pace
55
59
61
98
99
100
101
105
106
107
108
119
iv
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LIST OF TABLES
Pace
TABLE I: Typical Operating Costs for a 1.5 MGD
Plant 16
TABLE II: Typical Flow Rates for Various Filter
Aids 17
TABLE III: Typical Raw Water Analysis - Dark Water
Discharge 24
TABLE IV: Particle Size Distribution - Limestone
Slurry 25
TABbE V: Typical Raw Water Analysis - Rushton
Mining Company 34
TABLE VI: Filter Aid Comparisons 35
TABLE VII: Alkali Combination Summary 36
TABLE VIII: Data From 24 Hour Runs 42
TABLE IX: Typical Raw Water Analysis - Bennett Branch 48
TABLE X: Data from Preliminary Test Runs 50
TABLE XI: Particle Size Distribution - Pulverized
Limestone (Rock Dust) 56
TABLE XII: Average Raw Water Analysis - Proctor No. 2 . 58
TABLE XIII: Particle Size Distribution - Air-jet Milled
Limestone 62
TABLE XIV: Experimental Program 63
TABLES XV.1-27: Run Data Summaries - Levels 1 through 27 ... 66-92
TABLES XVI.1-2: Run Data Summaries - Air-jet Milled
Limestone 93-94
TABLE XVII: Run Data Summary - Lime Only 95
TABLE XVIII: Run Data Summary - Polyelectrolyte
Conditioning 96
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LIST OF TABLES
Page
TABLE IXX: Composite Analysis - 24 Hour Run 103
TABLE XX: Material Balance - 24 Hour Run 104
TABLE XXI: Capital Cost Estimate - Rushton Mining
Company 112
TABLE XXII: Operating Cost Estimate - Rushton Mining
Company 113
TABLE XXIII: Capital Cost Estimate - Bennett Branch 115
TABLE XXIV: Operating Cost Estimate - Bennett Branch ... 116
TABLE XXV: Capital Cost Estimate - Proctor No. 2
Limestone-Lime Process 117
TABLE XXVI: Operating Cost Estimate - Proctor No. 2
Limestone-Lime Process 118
TABLE XXVII: Capital Cost Estimate - Proctor No. 2
Lime Only 120
TABLE XXVIII: Operating Cost Estimate - Proctor No. 2
Lime Only 121
vi
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SECTION I
CONCLUSIONS
1. The sedimentation and filtration unit processes were found to be
the major factors contributing to treatment costs for systems
using chemical neutralization followed by solids concentration
and dewatering via rotary vacuum precoat filtration.
2. The optimum economic system design for a given chemical process
can be found by optimizing the individual unit processes with
the exception of the sedimentation and filtration processes. Due
to the interaction between these processes, they should be con-
sidered as a single unit process in optimizing the design of the
system.
3. The use of polyelectrolytes appeared to offer an economic means
of increasing sludge concentration, thereby reducing the sludge
volume and the respective filtration costs.
4. The presence of unreacted limestone appeared to enhance the
settleability and filterability of the sludge.
5. Chemical neutralization with a combination of limestone and lime
offers a definite cost advantage over lime alone and operational
advantages over limestone alone.
6. Production of a fine limestone slurry by attrition of rock in a
wet mill on-site appeared to be the most economical method for
feeding limestone.
7. Optimum conditions for operation of the rotary vacuum precoat
filter are a drum speed of one revolution per minute, 30 per
cent submergence, a CELITE 501 precoat, and a knife advance of
0.001 inches per drum revolution.
-1-
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SECTION II
RECOMMENDATIONS
The tests were inconclusive in determining the optimum chemical addi-
tion levels for treatment of mine drainage with limestone and lime in
a combined process. There was also a degree of uncertainty in the
optimization calculations for design of the sedimentation and filtra-
tion equipment. It is recommended that a designed experimental program
to evaluate relationships between limestone dosage, lime dosage, sludge
settling rates as a function of solids concentration, and filtration
rates as a function of solids concentration be undertaken to confirm and
expand on the relationships developed under this program. This could be
accomplished on a bench-scale using batch operations. The data could be
analyzed using the computerized design and cost estimating techniques
developed under this program to optimize the important variables in the
limestone-lime neutralization process.
-3-
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SECTION III
INTRODUCTION
The discharge of acidic waters containing high concentrations of
ferrous iron has resulted in a serious pollution problem in numerous
streams and other waterways in Appalachia. The polluted conditions of
these discharges from both active and inactive coal mining operations
is caused by the oxidation of sulfur-bearing minerals, primarily the
pyrites associated with most coal seams, in the presence of water to
produce sulfuric acid. The acid subsequently dissolves minerals with
which it comes in contact resulting in a highly mineralized acidic
discharge. The acid present can be disastrous to living matter in the
streams as evidenced by \the massive fish kills in recent years. The
Environmental Protection Agency and the Commonwealth of Pennsylvania,
as part of their programs to investigate techniques of mine drainage
pollution abatement, have jointly sponsored a project undertaken by
Johns-Manville Products Corporation to develop and optimize chemical
techniques in conjunction with sludge dewatering via rotary vacuum
precoat filtration for the treatment of coal mine drainage.
The treatment of this type of waste involves four unit operations:
Neutralization, aeration, sedimentation, and sludge dewatering or
concentration. The neutralization step is accomplished via addition
of one or more chemical alkalies to the discharge water in an agitated
vessel. Aeration is used to promote the oxidation of ferrous iron to
the more readily precipitated ferric state. Sedimentation removes the
precipitated iron from the discharge resulting in two streams, an
overflow of quality acceptable for discharge to waterways and a con-
centrated underflow. The underflow is then further concentrated by
dewatering on a rotary vacuum precoat filter so that the solids may
be disposed of in an acceptable manner such as by use in land fill
operations.
Chemical alkalies are used to neutralize the sulfuric acid present
in the discharges as well as the acidity resulting from the hydrolysis
reactions of ferrous and ferric iron. Since both of the hydrolysis
reactions are equilibrium reactions, it is essential to neutralize the
generated acidity to promote the continued formation of the iron
hydroxides. It has been reported(1) that ferric hydroxide will form
at a pH of around 5.5 whereas ferrous hydroxide does not form until a
pH of 9.5 to. 10 is reached. The range of acceptable pH for discharge
in Pennsylvania is 6 to 9. Aeration is therefore utilized to oxidize
the ferrous iron to ferric resulting in precipitation of the iron at a
lower pH so that the standards for iron (less than 7 mg/1) and pH can
be met.
references refer to the bibliography.
-5-
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One of the most common methods for removal of solids from liquid streams
is sedimentation. Unfortunately, sedimentation equipment often performs
unsatisfactorily due to failure to consider all of the fundamental factors
involved in designing the system. Poor design gives rise to the problem
of solids escaping with the effluent. In the cylindrical clarifier/
thickener utilized during the test work, the major difficulties encountered
were with uniform flow distribution and upflow velocities exceeding the
settling rate of the solids. When the latter condition exists, the solids
are carried over with the overflow.
The rotary vacuum precoat filter (Figures 1 and 2) is a modification of
the rotary vacuum filter that combines the feature of almost continuous
operation while eliminating the primary maintenance difficulty of a
plugged filter septum. In operation, a thick precoat of filter aid, two
to four inches thick, is applied from clean liquid to the surface of the
filter drum. Once the precoat is in place, the precoating liquid is dis-
placed from the filter bowl by the sludge to be filtered. The drum is
continuously rotated with from 30 to 50 per cent of the surface submerged
in the sludge. As the drum rotates, three phases of operation are per-
formed during each revolution. These are solids deposition, solids
dewatering, and solids removal. The solids are deposited by straining
action as the liquid is drawn through the precoat into the vacuum system.
As the drum rotates out of the sludge, air is drawn through the solids
and the precoat dislodging the water from the deposited solids. A knife
controlled by an automatic advance mechanism removes the solids along with
a small amount of the precoat on each revolution of the drum, thus ex-
posing a clean surface for filtration. This type of filter can handle
extremely difficult filtration problems because of the features of
continuous solids removal and exposure of a fresh surface of the precpat
on each revolution of the drum.
Pilot Plant System
The pilot plant treatment system was fabricated from the following equip-
ment :
1. The U.S. Bureau of Mines' 4-foot diameter by 24-foot long tube
mill(2) which was used to produce a fine limestone slurry from
one-half inch to two inch rock. This mill is shown in Figure 3.
2. The Pennsylvania Department of Environmental Resources' Operation
Yellowboy Trailer. This trailer contains a variable capacity feed
pump, a 50-gallon flash mixer with agitator and screw feeder, a
1200-gallon agitated aerator tank with a 17-cfm blower-sprayer
unit, a 1000-gallon thickener, and a variable speed sludge recycle/
discharge pump.
-6-
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FIGURE 1 - ROTARY PRECOAT FILTER
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I
00
I
FIGURE 2- ROTARY PRECOAT FILTER - CUTTI NG
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VD
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FIGURE 3 - TUBE MILL
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3. Johns-Manville's 6-inch face by 36-inch diameter rotary vacuum precoat
filter with a variable speed drum drive, variable speed knife advance
and 30 and 50 per cent submergence ports in the filter bowl.
A flow diagram of this system as set up at the first three sites is pre-
sented in Figure 4. In an attempt to increase the limestone efficiency,
a slightly different setup was used at the fourth site. This is pre-
sented in Figure 5. The theory behind this was to allow the limestone
time to react in the presence of a high acidity before adding the
additional alkali.
All alkali feeds, with the exception of the limestone slurry, were made
using dry feeders. The limestone slurry was produced by attritio.n^of
limestone rock in a tube mill as described by E. A. Mihok et al.
Experimental Procedures
The work at the first site was limited to production of sludge for use
in making filtration runs. The neutralization and sedimentation equip-
ment was operated at throughput rates varying from 10 to 30 gallons per
minute with intermittent sludge draw off. Limestone addition was adjusted
so that the effluent pH was at least 7. The rotary vacuum precoat filter
was operated at a constant drum speed of one revolution per minute with
50 per cent submergence. The knife advance rate and filter aid grade
were varied and the filtration rate and discharge cake solids content
measured.
The second and third sites were used to evaluate the use of different
chemical alkalies in combination with either limestone or lime. Con-
stant flow conditions consisting of 20 gallons per minute raw flow
rate and a continuous sludge draw of 2 gallons per minute were used.
The primary variables measured to evaluate the performance of the
neutralization and sedimentation equipment were overflow pH, iron
concentration, turbidity, and acidity and the sludge solids con-
centration. The filter was operated under the same conditions used
at the first site.
The work at the last site concentrated on developing data regarding
the effects of different operating variables on performance of the
neutralization and sedimentation unit processes for a process that
attempted to use a combination of limestone and lime more efficiently
than at the other sites. A statistically designed experiment was used
to study the relative effects of these variables on the economics of
the process. During this portion of the test work, sludge filtera-
bility tests were conducted on the Johns-Manville 0.1 square foot
rotary vacuum precoat test leaf, which is shown in Figure 6.
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OTHER ___ (—T
ALKALI ~A I I
FLASH
MIXER
MINE
WATER
LIMESTONE
SLURRY
TANK
AERATOR
THICKENER
I SLUDGE
THICKENER OVERFLOW
PRECOAT
FILTER
FILTER
CAKE
TO STREAM
FIGURE 4 - ORIGINAL SYSTEM
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MINE
WATER
FLASH
MIXER
Y
LIMESTONE
FEED
AERATOR
LIME
FEED
&•
THICKENER
SLUDGE
THICKENER OVERFLOW
SLUDGE
RECYCLE
I
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FIGURE 6 - PRECOAT TEST LEAF
-13-
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The filtration work at this last site was expanded to evaluate the
effects of varying drum speed at both 30 and 50 per cent submergences.
CELITE 501 was used for precoating and the knife advance rate was varied
at all conditions.
Detailed analysis of the results obtained at each of the sites are
presented in Appendixes A through D. Appendix E describes the results
of economic analysis that were made for the different processes.
-14-
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SECTION IV
DISCUSSION
The use of limestone in neutralization of the acidity in mine water
appears to offer advantages to the economics of treatment. The bene-
fits are derived from the lower cost of limestone as compared with lime
and the better settling and filtration characteristics of solids con-
taining unreacted limestone. There are also some disadvantages that may
actually result in higher costs. These must be taken into consideration
when designing a treatment system using limestone. Limestone is an
extremely inefficient neutrallzer. Tests Indicate that only about 35 per
cent of the limestone is actually reactive in neutralizing mine water.
There has been work done'-*) that has shown that the efficiency of lime-
stone is dependent on particle size, calcium and magnesium content, and
surface area. The above efficiency was based on a slurry with a volume
average diameter of 6 microns. Use of a commercially available pulverized
limestone with a volume average diameter of 46 microns gave an efficiency
of 25 per cent. The use of finer limestone is therefore desirable based
on operating criteria. However, the costs of reducing the particle size
can result in a material costing more than lime. The use of on-site
production of a fine limestone slurry from rock in some sort of wet mill
appears to be the most economical method of supply.
The use of an additional alkali with limestone such as lime or magnesite
to produce higher final effluent pH's also appeared to improve the
settleability characteristics of the solids without adversely affecting
the filtration characteristics. The main objective of the preliminary
work had been to replace a portion of the excess limestone with the
additional alkali. Since the costs did not appear to be overly increased,
further optimization of the ratio of limestone and other alkali resulting
in better economics was a possibility. Typical estimated operating costs
are given in Table I. A statistically designed experiment was utilized
to attempt to define the effects of various operating variables on the
economics of a limestone and lime process. Unfortunately, the effects
of either limestone or lime dosages were found to be insignificant for
the system studied because of the high costs of the filter installation
and operation. The results of these tests are further described in
Appendix D. The indication of the significant part played by filtration
in the economics of the treatment system places considerably importance
on optimizing this unit process.
CELITE 501 was the best suited filter aid grade based on tests run at
three of the four sites. A typical comparison is given in Table II.
No comparative tests were conducted at the fourth site. The optimum
knife advance in all cases was in the range of 0.0010 to 0.0015 inches
-15-
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TABLE I
Typical Operating Costs
for a 1.5 MGD Plant
Neutralization Cost per 100 Ib Acidity
Lime $8.00
Limestone-Lime $5.30-$6.50+
Limestone $5.00-$5.20*
^Depends on ratio used. Lower figure is based on process
used at Proctor 2.
Quality of effluents is questionable.
-16-
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TABLE II
Typical Flow Rates
for Various Filter Aids
Filter Aid
Grade
HYFLO
CELITE 501
CELITE 503
CELITE 545
Knife Advance
mil/min
1.3
1.3
1.3
1.3
Flow Rate
gsfm
0.58
0.60
0.55
0.55
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per drum revolution. In comparing the differences between operation at
50 and 30 per cent submergences, it must be considered that a 20 per
cent savings on equipment cost will be realized with the 30 per cent
submergence unit., In addition, the cost to maintain the seals on a
50 per cent submergence unit will represent a significant cost factor.
For these reasons, most filter manufacturers do not recommend the use
of a 50 per cent submergence unit. The economics of lower capital cost
and higher filter aid requirements appear to be offsetting. Consequently,
the use of a 30 per cent submergence unit with a knife advance of 0.001
inches per revolution and a CELITE 501 precoat appears to offer the best
performance.
The factors that would govern the size of the filter unit should also
be considered. The data obtained at the last site indicated a somewhat
inverse linear relationship between filtration rate and solids con-
centration of the sludge. For a given feed concentration, the higher
solids concentrations are associated with lower sludge volumes. An
optimization calculation indicated that a solids concentration of 1.1
per cent resulted in the least cost. However, as indicated in Appen-
dixes D and E, when the cost of a thickener to produce the desired
sludge concentration is also considered, the optimum concentration
becomes considerably reduced. This thus places that major responsibility
for the bulk of the economics of treatment on both the sedimentation
and dewatering processes. Optimization of one cannot be attempted
without considering the effects on the other. Some techniques that
could be useful in reducing the costs of treatment would be the use of
polyelectrolytes to aid in the thickening of the sludge. A run
conducted at the last site using a polyelectrolyte significantly in-
creased the sludge solids concentration. The filterability of the
sludge did not contradict the characteristics that would be expected
if no polyelectrolyte were used. The use of a multiple step clarifi-
cation and thickening process may also offer an economic solution.
The type of neutralization process utilized may also have an effect
on these costs. The difference in flow rates obtained at the first
three sites as opposed to the last site may have been the result of
the presence of large amounts of unreacted limestone in the sludge.
Further data would be needed to verify this conclusion.
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SECTION V
ACKNOWLEDGMENTS
The work summarized in this report was jointly sponsored by the Coal
Research Board, Commonwealth of Pennsylvania and the Water Quality
Office, Environmental Protection Agency. The guidance and assistance
of Dr. David Maneval of the Pennsylvania Department of Environmental
Resources and Mr. Ronald Hill of the Water Quality Office, Environ-
mental Protection Agency is acknowledged with sincere thanks.
The assistance of the following groups from the Johns-Manville
Research & Engineering Center is gratefully acknowledged: The
Celite Filtration Section for operation of the pilot plant, the
Analytical Chemistry Section for sample analysis, and the Physics
Section for assistance in statistical design and data evaluation.
Acknowledgment is also given with sincere thanks to the Reading
Anthracite Company, the Rushton Mining Company, and Pennsylvania
State University for furnishing test sites and to Dr. Lovell of the
Pennsylvania State University for his assistance.
-19-
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SECTION VI
REFERENCES
1. Holland, C.T., Berkshire, R.C., and Golden, D.F., "An Experi-
mental Investigation of the Treatment of Acid Mine Water
Containing High Concentrations of Ferrous Iron with Limestone,"
3rd Symposium on Coal Mine Drainage Research Preprints,
Pittsburgh, Pa., pp 52-65 (1970).
2. Mihok, E.A., Deul, M., Chamberlain, C.E., and Selmeczi, J.G.,
"Mine Water Research—The Limestone Neutralization Process,"
U.S. Bureau of Mines Report of Investigation 7191 (1968).
3. Bituminous Coal Research, Inc., "Studies on Limestone Treatment
of Acid Mine Drainage," Federal Water Quality Administration
Report 14010-EIZ 01/70 (1970).
4. Wilmouth, R.C., and Scott, R.B., "Neutralization of High
Ferric Iron Acid Mine Drainage," 3rd Symposium on Coal Mine
Drainage Research Preprints, Pittsburgh, Pa., pp 66-93 (1970).
5. Office of Saline Water, "A Standardized Procedure of Estimating
Costs of Saline Water Conversion," Report PB161375 (1956).
6. Dick, R.I., "Fundamental Aspects of Sedimentation," Water and
Wastes Engineering. 6, No. 2, pp 47-50 (February 1969) and 6,
No. 3, pp 44-45 (March 1969).
7. Olmsted, B.C., and Partak, R., "Precoat Filtration of Con-
centrated Sludges from Nine Mine Waters from Western
Pennsylvania Bureau of Mines Contract 14-09-0050-2931,"
Johns-Manville Research & Engineering Center Report E412-
8014-S1 (March 15, 1967).
8. Dorr-Oliver, Inc., "Operation Yellowboy," Report Submitted
to the Pennsylvania Coal Research Board (June 1966).
-21-
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APPENDIX A
DARK WATER DISCHARGE MINE. ST. CLAIR, PENNSYLVANIA
Site Description
The raw water was obtained from the natural overflow discharge of
the Dark Water Discharge Mine in St. Clair, Pennsylvania operated
by the Reading Anthracite Company. The discharge was a low iron
water with all iron present in the ferrous state. A typical analy-
sis of this discharge is given in Table III. The test program was
conducted during May and June 19b9.
Test Program Description
The pilot plant system is described in the main body of this report.
Due to the low sludge volumes produced by neutralization of the feed
water, the sedimentation equipment was operated primarily to produce
enough sludge to allow operation of the pilot filter unit. A lime-
stone slurry, produced by passing a stream of water through a tube
mill as described by E. A. Mihok et al(^) was used for neutralization.
The tube mill initially contained 7000 pounds of 98.6 per cent cal-
cium carbonate limestone purchased from the Appalachian Stone Division
of the Martin-Marietta Corporation. The tube mill was periodically
replenished by addition of unregulated amounts of the rock.
The average flow rate through the system was 25 gallons per minute,
alhtough runs were made ranging from 10 to 30 gallons per minute.
The limestone slurry feed rate averaged 1.2 gallons per minute
averaging 48.4 grams of calcium carbonate per gallon of slurry.
The sludge was withdrawn from the thickener intermittently and stored.
The rotary vacuum precoat filter was operated only when there was
sufficient sludge stored to allow a meaningful run.
Discussion
The limestone neutralization process was performed using a dosage of
488.5 mg/1. No attempts were made to optimize this dosage. Using
the free mineral acidity analysis of 108 mg/1, this represents a
usage efficiency of 22.2 per cent. This resulted in an overflow with
a pH in the range of 6.9 to 7.5. A sample of the limestone slurry
was analyzed for particle size distribution by the Coulter Counter
method. The results are presented in Table IV.
The aerator was operated to provide two basic operations. The first
was removal of carbon dioxide generated by the neutralization reaction.
-23-
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TABLE III
Typical Raw Water Analysis
St. Clair, Pennsylvania
pH
Total Acidity
Free Mineral Acidity
Total Iron
Ferrous Iron
Sulfates
Calcium
Magnesium
5.7
8 mg/1 (as CaCO,,)
108 mg/1 (as CaCO-j)
25 mg/1
25 mg/1
620 mg/1
250 mg/1 (as CaCO-j)
400 mg/1 (as CaCO-j)
-24-
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TABLE IV
The following table Is a Coulter Counter analysis of the limestone
slurry coming from the rotary neutralizer and being fed to the flash
mixer.
Weight Distribution
Average Particle Difference
Volume Diam. %
22511.60
11255.80
5627.90
2813.95
1406.98
703.49
t
351.74
175.87
87.94
43.97
21.98
10.99
5.50
2.75
1.37
0.69
0.34
34.58
27.44
21.78
17.29
13.72
10.89
8.65
6.86
5.45
4.32
3.43
2.72
2.16
1.72
1.36
1.10
0.87
0.0
2.49
0.0
1.87
3.11
5.76
7.16
10.55
12.80
13.93
12.99
10.79
10.78
4.57
2.20
0.69
0.24
Less Than
%
100.00
97.51
97.51
95.64
92.53
86.77
79.61
69.06
56.27
42.34
29.35
18.56
7.78
3.20
1.00
0.31
0.07
Number Distribution
Difference
%
0.0
0.0
0.0
0.01
0.02
0.09
0.22
0.66
1.61
3.50
6.53
10.84
21.67
18.38
17.72
11.16
7.58
Less Than
%
100.00
100.00
100.00
99.99
99.97
99.88
99.65
98.99
97.38
93.88
87.35
76.51
54.84
36.46
18.74
7.58
0.0
Volume average diameter is 5.79 microns. Area average diameter
3.72 microns. Length average diameter is 2.66 microns.
is
-25-
-------
The carbon dioxide would otherwise have the effect of buffering the
solution thus inhibiting the iron precipitation reaction and reducing
the efficiency of limestone usage. The second function was to oxidize
iron from the ferrous to the ferric state. Analyses showed that almost
total oxidation occurred. This result would be expected because only
2.36 grams per minute of ferrous iron was being fed. The "Operation
Yellowboy"(8) report stated that the aerator was deisnged to provide at
17 cfm sufficient oxygen to oxidize 121 grams per minute (assuming 100
per cent efficiency) of ferrous iron to the ferric state.
The aeration and sedimentation equipment was operated at throughput rates
ranging from 10 to 30 gallons per minute. The effect of varying the flow
rate in the aerator was primarily a change in detention time.
The effect of flow rate on operation of the thickener is very significant.
Since the thickener was operated with only intermittent sludge draws, a
change in the raw flow rate was a direct change in the overflow rate,
assuming an even distribution of upward flow in the annular clarification
region of the thickener. Thus, the upflow velocity range during these
tests would ideally have been 3.17 feet per hour at 10 gallons per minute
to 9.52 feet per hour at 30 gallons per minute. For efficient clarifi-
cation, the settling rates would therefore have to exceed these upflow
velocities. The settling rates could not be measured by the standard
settling tests using 1 liter graduated cylinders because of the extremely
low volumes of sludge produced. The average solids concentration in the
thickener influent was on the order of 330 mg/1.
The only qualitative analysis of the thickener function that could be
obtained was by examining the operation of this unit. The overflow
clarity was found to deteriorate with time at the 10 gallon per minute
flow rate (Figure 7). This would indicate that as the sludge blanket
built up towards the level of the feed distributor, a greater portion
of the solids were carried into the clarification zone and out with
the overflow. Thus, it can be concluded that the settling rate of the
solids was less than 3.17 feet per hour.
Some attempts were made to improve the efficiency of operation of the
thickener by increasing the settling rate of the solids. Calcined
magnesite was known to produce a faster settling iron floc.^'' Addition
of a concentrated slurry to the distribution zone of the thickener was
unsuccessful. Recycling of sludge to the distribution zone, thus
effectively increasing the solids concentration of the feed, was also
unsuccessful. The use of polyelectrolytes to promote formation of a
denser and therefore faster settling floe was also attempted. Jar tests
using Catfloc (Calgon) and Magna Floe 985 N (American Cyanamid) showed
some improvement. Again, however, qualitative settling tests could not
be run due to low sludge volumes. A run at a feed rate of 25 gallons per
-26-
-------
TOO
80
60
40
03
at
20
FIGURE 7
OVERFLOW TURBIDITY AS A FUNCTION OF TIME
FLOW RATE 10 GPM
20
40 60 80 100
TIME FROM START - MINUTES
120 140
-------
minute (overflow velocity of 7.93 feet per hour) using Purifloc 601 (Dow)
was also unsuccessful. Since the primary purpose of operation at this point
had become to produce sufficient sludge for operation of the filter unit, no
qualitative analysis of the effects of these methods was attempted.
Rotary vacuum precoat filtration did an excellent job in dewatering the
sludges produced. Figure 8 shows the relationship between knife advance,
sludge solids concentration and filtrate flow rate for CELITE 501. The
sludge solids concentration does not appear to have a significant effect
based on this data. The optimum knife advance appears to be somewhere
between 0.001 and 0.002 inches per drum revolution. Filtrate clarities on
the order of 5 JTU and iron concentrations less than 1 mg/1 were obtained.
Figures 9 and 10 present the knife advance/filtrate flow rate relationship
for filter aid grades CELITE 545 and 503. The CELITE 545 gave approxi-
mately the same filtrate flow rate as CELITE 501 and would therefore be ruled
out on the basis of economics. CELITE 503 gave lower filtrate rates and was
therefore ruled out. CELITE 501 was thus the optimum filter aid grade used
at this site. The cake discharge averaged 64 per cent dry solids.
Conclusions
The operation of a standard neutralization, aeration, sedimentation, and
sludge dewatering system on a source water of this nature caused consid-
erable problems in operation. Due to the extremely low volume of sludge
produced, the controlling design factor for the sedimentation unit would
be the overflow velocity. This would result in a unit capable of handling
a solids volume much larger than actually present.
An economic alternative to the above process could be a two-step process
involving chemical pretreatment followed by filtration of the entire stream
using standard diatomite pressure or vacuum filters. The techniques for
this process have been well developed by Johns-Manville for use on potable
and industrial feed waters. An iron concentration similar to the St. Clair
water has been encountered by Johns-Manville in work done at the DuPont
Plant in Deepwater, New Jersey. The cake discharge using this process
could be either wet or dry.
-28-
-------
1.0
FIGURE 8
KNIFE ADVANCE.CURVE
0.8
z
i
h-
u.
x 0.6
o
i
0.4
0.2
8
SLUDGE SOLIDS
X 1.12%
O 0.72%
Q 0.66%
CONDITIONS
FILTER AID- CELITE^SOl
SUBMERGENCE-50%
DRUM SPEED - 1MIN/REV
0.002 0.004
KNIFE ADVANCE- INCHES/MINUTE
0.006
-------
1.0
0.8
£ 0.6
o
I
UJ
O
0.4
0.2
FIGURE 9
KNIFE ADVANCE CURVE
i
o
CONDITIONS
FILTER AID - CELITE^45
SUBMERGENCE-50 %
DRUM SPEED - 1 MIN/REV
SLUDGE SOLIDS - 1.08%
0.002 0.004
KNIFE ADVANCE- INCHES f MINUTE
0.006
-------
FIGURE 10
KNIFE ADVANCE CURVE
i
u>
0.8
? 0.6
M
? 0.4
0.2
CONDITIONS s^
FILTER AID - CE LITERS03
SUBMERGENCE -50%
DRUM SPEED - 1 MIN/REV
SLUDGE SOLIDS -1.32%
0.002 0.004
KNIFE ADVANCE' INCHES/ MINUTE
0.006
-------
APPENDIX B
RUSHTON MINING COMPANY, OSCEOLA MILLS. PENNSYLVANIA
Site Description
The raw water was obtained from the holding pond receiving mine discharge
at the Rushton Mining Company mine located at Osceola Mills, Pennsylvania.
The flow to the pond was intermittent, the pumps being controlled by level
probes in the mine. An average analysis of the mine water is presented in
Table V. The test work at this site was performed in July and August 1969.
Test Program Description
Tests were conducted to evaluate various techniques of chemical neutrali-
zation from both the operational and economic viewpoints. In all, four
combinations of alkalies were used in the neutralization step. These
included limestone with magnesite, limestone with lime, lime with magne-
site, and limestone alone. With the exception of the limestone, chemicals
were fed by dry feeders. The limestone was fed as a slurry produced by
attrition of limestone rock in a tube mill.^ '
Four filter aid grades (HYFLO SUPER-GEL, CELITE 501, CELITE 503 and CELITE
545) were evaluated while using the limestone with magnesite neutralization,
The grade with the best balance of flow rate per unit area and usage was
used in evaluating the other neutralization processes.
Discussion
The tests run for the purpose of evaluating the four filter aid grades are
summarized in Table VI. At the optimum knife advance of 0.0013 inches per
revolution, CELITE 501 exhibited the highest flow rate. It was therefore
chosen for use in the subsequent tests.
The initial tests involved a comparison of the three chemical neutrali-
zation techniques utilizing a combination of two chemical alkalies. The
purpose of the dual chemical feeds was to utilize limestone (lime in the
case of the lime-magnesite combination) as the primary neutralizing agent
with the additional alkali provided as a sort of polishing step. The
limestone feed rate was controlled by the pH of the feed to the flash
mixer. A pH of 6 was the goal. All chemical feeds were made prior to the
aerator. The additional alkali was added to produce an effluent with pH
between 7.5 and 8.5. No attempts were made to optimize the additions of
the two alkalies. The results of these tests are summarized in Table VII,
and the filtration data is presented in Figures 11 to 14. Since all testa
were run under constant flow conditions, a 20 gallon per minute feed and
-33-
-------
TABLE V
Typical Raw Water Analysis
Osceola Mills, Pennsylvania
pH
Ferrous Iron
Total Iron
Calcium
Magnesium
Silica
Sulfates
Free Mineral Acidity
Total Acidity
Total Solids
3.3
45 mg/1
159 mg/1
410 mg/1 (as CaC03)
270 mg/1 (as CaC03>
31 mg/1
2665 mg/1
356 mg/1 (as CaCO-j)
367 mg/1 (as CaCO.j)
1420 mg/1
-34-
-------
TABLE VI
Filter Aid Comparisons
Filter Aid
Filtrate
pH
Total Iron, mg/1
Turbidity, JTU
HYFLO 501 503 545
7.8 8.9 8.9 8.3
0.3 1.4 0.2 4.0
2.8 2.1 1.5 3.7
Cake
Per Cent Solids 35.4 42.3 48.8
Optimum Knife Advance, mils/min 1.30 1.30 1.30 1.30
Flow Rate, gsfm 0.575 0.600 0.550 0.550
-35-
-------
TABLE VII
Data From Preliminary Test Runs
Filter Aid - CELITE 501
Limestone
Magnesite
Clarifier Overflow
pH 8.5
Total Iron, mg/1 5.1
Calcium, mg/1 621
Total Hardness, mg/1 1073
Suspended Solids, mg/1 51
Total Solids, mg/1 1700
Clarifier Underflow 5921
Suspended Solids, mg/1
Filtrate
pH 8.9
Total Iron, mg/1 1.4
Turbidity, JTU 2.1
Filter Cake Per Cent Solids 42.3
Limestone
Lime
7.6
2.9
856
1030
32
1450
7089
7.8
0.1
1.6
29.6
Lime
Magnesite
7.
4.
686
988
53
1644
7.
0.
2.
24.
5
7
-
6
2
1
8
-36-
-------
0.8
O
i 0.4
0.2
FIGURE 11
KNIFE ADVANCE CURVE
LIME & MAGNESITE WITH AERATION
CONDITIONS
FILTER AID
SUBMEGENCE
DRUM SPEED
CELITE 501
50%
1 MINX REV
0.002 0.004
KNIFE ADVANCE - INCHES / MINUTE
0.006
-------
FIGURE 12
KNIFE ADVANCE CURVE
LIME & MAGNESITE WITHOUT AERATION
0.8
o.*
i
CO
<
O
0.4
O
0.2
CONDITIONS
FILTER AID
SUBMERGENCE
DRUM SPEED
501
CELITE
50
1 MIN/REV
JL
J.
0.002 0.004
KNIFE ADVANCE -INCHES'MINUTE
0.006
-------
i
OJ
vo
0.8
£ 0.6
V
O
i
0.4
0.2
FIGURE 13
KNIFE ADVANCE CURVE
LIMESTONES, MAGNESITE
CONDITIONS
FILTER AID
SUBMERGENCE
DRUM SPEED
CEL1TE~501
50%
1 MIN / REV
0.002 0.004
KNIFE ADVANCE - INCHES/ MINUTE
0.006
-------
0.8
I 0.6
?0.4
FIGURE 14
KNIFE ADVANCE CURVE
LIMESTONE & LIME
I
o
0.2
CONDITIONS p.
FILTER AID CELITE^SOl
SUBMERGENCE 50 %
DRUM SPEED 1 MIN/REV
0.002 0.004
KNIFE ADVANCE-INCHES/MINUTE
0.006
-------
a continuous 2 gallon per minute sludge draw, the 18 gallon per minute
overflow rate (ideal upflow velocity of 5.7 feet per hour) did not appear
excessive for any of the three techniques. Based on the analysis of the
overflow and underflow suspended solids concentrations, the limestone-
lime combination resulted in the best settling sludge while lime-magnesite
produced the worst settling characteristics. The limestone-magnesite
combination, however, produced the sludge with the best filtration
characteristics, giving the highest filtrate flow rate and per cent solids
in the discharged cake. Based on the high capital and operating costs of
the filter station, the limestone-magnesite combination was selected for
comparison with limestone only neutralization during round-the-clock
operation of the system.
The data obtained during round-the-clock operation of the system is
summarized in Table VIII and Figures 15 and 16. The use of straight
limestone neutralization appeared to give marginal results in operation
of the thickener at the 18 gallon per minute overflow rate. It would
therefore be desirable to design for a lower overflow rate in process
scale-up. The limestone-magnesite would appear to be a better choice
based on overflow quality, higher filtrate flow rate, and higher filter
cake solids content. The high cost of magnesite may be, however, an
offsetting factor. Economic analysis is presented in a separate part
of the report. In the straight limestone technique, a usage efficiency
of 34 per cent was obtained.
The use of aeration at this site did not appear to be as beneficial as
at other sites. Due to the low ratio of ferrous iron to total iron in
the raw water, the oxidation of ferrous to ferric iron is of minor
importance as this reaction had occurred primarily in the holding pond
prior to being fed to the experimental system. The use of aeration to
strip carbon dioxide generated by the limestone reaction was probably
of some benefit. The use of air in the aerator also served to increase
the degree of agitation present in this vessel. Operationally, this
increased agitation appeared to do more harm than good. It appeared
that excessive floe breakdown resulted which, in turn, produced a poorer
settling sludge in the thickener feed. Examination of Figures 11 and 12
would indicate that the filterability of the resultant concentrated sludge
may also be affected.
Conclusions
At a site where significant oxidation of ferrous to ferric iron occurs
prior to the neutralization step, the use of additional aeration seems
to produce mostly an increase in the degree of agitation in the aeration
vessel which was detrimental. The aeration required to remove carbon
dioxide generated by the reaction with limestone is probably considerably
less than was used during these tests.
-41-
-------
TABLE VIII
Data From 24-Hour Runs
Raw Sample Average
pH
Ferrous Iron, mg/1
Total Iron, mg/1
Calcium, mg/1
Total Hardness, mg/1
Clarifier Overflow
PH
Total Iron, mg/1
Calcium, mg/1
Total Hardness, mg/1
Sludge
% Solids
Filtrate
pH
Total Iron, mg/1
Calcium, mg/1
Total Hardness, mg/1
Filter Cake
% Solids
3.1
48
165
440
784
Limestone-Magnesite
8.0
6.0
703
1180
0.5
Limestone
7.0
7.0
848
1098
0.3
8.1
0.3
598
1069
7.3
0.2
744
1100
45
32
-42-
-------
FIGURE 15
FLOW RATE - 24 HOUR RUN
LIMESTONE & MAGNESITE
0.8
z
5 0.6
ex
I i-
•P- u.
V N
<
O
, 0.4
LLJ
H>
IK
5
0
"" 0.2
0
-
O
o
o
0 AVERAGE
^ _O _O _ __
(7 T> 0
o °° 0 ooooo
o o o
•
CONDITIONS p.
FILTER AID CELITE^SOI
SUBMERGENCE 50
DRUM SPEED 1 MINX REV
10 15
TIME - HOURS
20
-------
0.8
FIGURE 16
FLOW RATE - 24 HOUR RUN
LIMESTONE WITH AERATION
z
< 0.6
<
O
0.4
xxxxx
A
X X
X AVERAGE
0.2
CONDITIONS
FILTER AID
SUBMERGENCE
DRUM SPEED
CELITE
50%
1 MINXREV
501
10 15
TIME - HOURS
20
-------
The use of a second alkali in combination with limestone appears to be
beneficial from two standpoints. The final pH obtainable can be in-
creased, thereby insuring complete precipitation of all iron present.
In addition, precipitated floes appear to have faster settling rates•
-45-
-------
APPENDIX C
BENNETT BRANCH. HOLLYWOOD. PENNSYLVANIA
Site Description
The raw water was obtained from Bennett Branch adjacent to the pumping
station feeding the experimental treatment facility operated by the
Pennsylvania State University. A typical analysis of this waterway is
given in Table IX. The work at this site was performed in September 1969.
Test Program Description
The system was operated at a throughput of 20 gallons per minute using
seven different techniques for neutralization. The techniques consisted
of various combinations of chemical alkalies as follows:
1. Limestone slurry with magnesite
2. Limestone slurry with lime
3. Limestone rock dust with magnesite
4. Limestone rock dust with fully calcined dolomite
5. Limestone slurry with partially calcined dolomite
6. Limestone slurry
7. Limestone rock dust
The test work performed at this site was limited because of a deadline
for removal of the equipment to avoid interferring with the shakedown
of the treatment facility equipment. The tests were run using a CELITE
501 precoat on the rotary vacuum precoat filter. One duplicate run using
a CELITE 545 precoat was also made.
All chemicals were fed by means of a dry feeder with the exception of the
limestone slurry. The limestone slurry was produced by attrition of lime-
stone rock in a tube mill.^ '
Discussion
Sludge flow rates were controlled as well as possible in the range of
2-4 gallons per minute. It was the intention during these tests to
-47-
-------
TABLE IX
Typical Raw Water Analysis
Bennett Branch
Hollywood, Pennsylvania
pH
Ferrous Iron
Total Iron
Calcium
Magnesium
Silica
Sulfates
Free Mineral Acidity
Total Acidity
Total Solids
3.3
58 mg/1
67 mg/1
185 mg/1 (as CaCO-j)
70 mg/1 (as CaCO-j)
30 mg/1
1480 mg/1
311 mg/1 (as CaC03)
337 mg/1 (as CaCO-j)
1060 mg/1
-48-
-------
maintain steady flow rate conditions. Under these conditions, the over-
flow rate was in the range of 16-18 gallons per minute (ideal upflow
velocity of 5.1 to 5.7 feet per hour). Analysis of the data presented
in Table X shows that only the limestone slurry, limestone rock dust,
and limestone with partially calcined dolomite techniques failed to
produce a satisfactory thickener overflow under these conditions. Due
to inaccuracies in the analytical method used in the field to determine
iron above 6 mg/1, the actual iron concentration could have been between
7 mg/1 and 35 mg/1 for any of these runs. In any case, the high iron
concentration was due to excessive carryover of precipitated iron floe.
The results of the filtration tests for the seven techniques are pre-
sented in Figures 17 to 21. The limestone slurry with partially calcined
dolomite appeared to give the best filtration characteristics. The only
combination, however, that did not produce filtration characteristics
fairly close to that of the limestone-partially calcined dolomite run
was the limestone rock dust with fully calcined dolomite. The overflow
pH during this run was a clear indication that an excessive dosage of the
fully calcined dolomite was being used. What effect optimizing this
dosage would have on the filterability characteristics is not known.
The comparison of the filtration tests for the runs using limestone slurry
and limestone rock dust is given in Figure 21. There is no distinct dif-
ference, although, referring to Table X, the limestone slurry sludge was
dewatered to a higher per cent solids in the cake. In neutralization,
however, the limestone slurry was found to be more efficiently utilized,
36.4 per cent as opposed to 26.6 per cent. The primary reason for this
would be the difference in particle size distributions. An earlier
particle size analysis of the limestone slurry (Table IV) showed it to
have a mean particle size approximately one-tenth of the limestone rock
dust (Table XI).
Conclusions
The use of either technique involving limestone alone or the limestone-
partially calcined dolomite combination would require a larger thickener
area than the other techniques. The similarity in filtration character-
istics would thus suggest that one of the techniques which produced a
satisfactory overflow would be economically desirable from capital costs
considerations.
The comparison between the limestone slurry produced by the rotary neu-
tralizer and the commerically available rock dust indicates that the finer
particle sizes in the slurry are considerably more efficient. Economically,
this says that the less expensive limestone rock would gain an even greater
advantage over the dust. The aeration requirements when utilizing limestone
dust could become a factor if a primarily ferric raw water is used. Some
aeration is provided for when using rock by the very nature of the attrition
process in the tube mill.
-49-
-------
TABLE X. Data From Preliminary Test Runs
Sample Source and Analysis
Raw
PH
Ferrous Iron, mg/1
Total Iron, mg/1
Calcium, mg/1
Total Hardness, mg/1
Free Mineral Acidity, mg/1
Total Acidity, mg/1
Sulfate, mg/1
Silica, mg/1
Total Solids, mg/1
Clarifier Overflow
PH
Total Iron, mg/1
Calcium, mg/1
Total Hardness, mg/1
Sulfate, mg/1
Silica, mg/1
Suspended Solids, mg/1
Total Solids, mg/1
Sludge - Per Cent Solids
Filtrate
pH
Total Iron, mg/1
Turbidity, JTU
Calcium, mg/1
Total Hardness, mg/1
Sulfates, mg/1
Silica, mg/1
Total Solids, mg/1
Suspended Solids, mg/1
Limestone Limestone Limestone
Limestone Limestone Dust Dust, Full Part. Calc,
Magnesite Lime Magnesite Calc. Pol. Dol.
Limestone Limestone
Dust
3.4
60.9
67.7
292
433
336
352
1799
31
1400
7.9
4.0
617
1017
1874
5
N.D.
N.D.
3.4
59.8
62.9
180
296
314
318
1384
32
1000
7.9
5.0
528
544
N.D.
7
28
900
3.3
58.6
67.6
164
276
298
330
1352
30
900
8.1
1.5
208
580
1536
4
23
1000
3.5
60.8
73.6
156
224
296
346
1386
28
1000
12
1.5
1244
1284
1338
N.D.
N.D.
1100
3.4
54.7
59.2
156
180
N.D.
N.D.
N.D.
N.D.
1000
7.5
7.5
540
700
N.D.
N.D.
N.D.
1200
3.1
55.8
68.1
172
188
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
7.0
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
3.1
55.8
68.1
172
188
N.D.
N.D.
N.D.
N.D.
N.D.
7.5
7.0
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
i
o
m
I
0.655
0.398
0.861
1.164
1.370
8.2
0.1
2.1
444
668
1838
4.5
550
20
7.7
0.1
2.3
472
500
1194
N.D.
N.D.
14
8.0
0.1
3.7
216
512
1446
2
900
7
11.9
0.1
4.2
1016
1032
1728
2
1100
N.D.
8.0
0.2
3.5
500
620
N.D
N.D
800
N.D
0.153
N.D.
0.1
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
0.105
N.D.
0.4
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
Cake - Per Cent Solids
37.0
30.7
43.3
27.6
44.7
49.9
38.2
-------
FIGURE 17
KNIFE ADVANCE CURVE
LIMESTONE & MAGNESITE
SUBMERGENCE 50%
DRUM SPEED 1MIN/REV
0 0.002 0.004 0.006
KNIFE ADVANCE-INCHES/MINUTE
-51-
-------
FIGURE 18
KNIFE ADVANCE CURVE
LIMESTONE SLURRY & LIME
0.8
<
o
I
CN1
LO
I
0.4
0.2
CONDITIONS
FILTER AID
SUBMERGENCE
DRUM SPEED
CELITE
50%
1 MIN/ REV
501
0
0.002 0.004
KNIFE ADVANCE- INCHES / MINUTE
0.006
-------
FIGUR.E 19
LIMESTONE DUST&FULLY CALCINED
DOLOMI TE
i
Ln
0.8
0.6
o
i 0.4
0.2
CONDIT IONS
F I LTER AlD
SUBMERGENCE
DRUM SPEED
501
CELITE
50 %
1 MIN/REV
.002 .004
KNIFE ADVANCE-INCHES/MINUTE
.006
-------
FIGURE 20
LI MESTONE SLURRY &
PARTIALLY CALCINED DOLOMITE
501
CONDITIONS
FILTER AID CELIT
SUBMERGENCE 5O%
DRUM SPEED 1 MIN/REV
0.002 0.004 0.006
KNIFE ADVANCE-INCHES/MINUTE
-54-
-------
FIGURE 21
FILTRATION PERFOMANCE OF
LIMESTONE SLURRY & ROCK DUST
1.0
0.8
CN
<
o
0.6
"L 0.4
0.2
DUST
CONDITIONS ^-v
FILTER AID- CELITE^SOl
SUBMERGENCE -50%
DRUM SPEED- 1 MIN/REV
0.002 0.004 0.006
KNIFE ADVANCE- INCHES / MINUTE
-55-
-------
TABLE XI
The following table is a Coulter Counter analysis of the Warner #80
rock dust used on the Bennett Branch water at Hollywood, Pennsylvania,
Weight Distribution
Average
Volume
1028915
771686
385843
192922
96461
48230
24115
12058
6029
3014
1507
754
377
188
94
Particle
Diam.
125.23
112.31
89.14
70.75
56.16
44.57
35.38
28.08
22.29
17.69
14.04
11.15
8.85
7.02
5.57
Difference
%
0.0
5.97
8.96
13.44
17.55
4.11
7.85
9.07
6.62
7.33
4.85
5.36
3.83
2.94
2.12
Less Than
%
100.00
94.03
85.07
71.63
54.07
49.97
42.12
33.05
26.43
19.11
14.25
8.90
5.06
2.12
0.0
Number Distribution
Difference
%
0.0
0.01
0.04
0.11
0.29
0.13
0.51
1.18
1.73
3.82
5.06
11.18
15.99
24.54
35.42
Less Than
%
100.00
99.99
99.95
99.84
99.56
99.42
98.91
97.73
96.00
92.18
87-12
75.94
59.96
35.42
0.0
Volume average diameter is 45.92 microns. Area average diameter is
24.60 microns. Length average diameter is 13.06 microns.
-56-
-------
APPENDIX D
PROCTOR 2. HOLLYWOOD. PENNSYLVANIA
Site Description
The raw water was obtained from the pump well of the Proctor 2 pumping
station feeding the Hollywood, Pennsylvania experimental mine drainage
treatment facility. The water was very high in both iron and acidity
compared to the other three sites. An average analysis is presented in
Table XII.
Experimental Program Description
The test work at this site concentrated on developing data on a process
utilizing a limestone with lime neutralization different from the pro-
cesses used at any of the other sites. It had been shown' ' that the
efficiency of limestone utilization decreased drastically above a pH of
6. It was felt that better economics might result if the limestone
addition was limited to a level where a higher utilization efficiency
would be realized and using lime to complete the neutralization.
The test program was broken down into four phases:
1. Jar tests to determine limestone dosage range that would include
the optimum dosage based on efficiency.
2. A statistically designed experimental program to investigate the
effects on plant cost of several controlled and uncontrolled
variables that would effect operating efficiency of the various
unit processes.
3. A detailed study of the effects of various operating variables on
the operation of the rotary vacuum precoat filter used for sludge
dewatering. The variables studied were submergence, drum speed,
and knife advance rate.
4. Operation on a round-the-clock basis to confirm the previously
collected data.
Discussion
A plot of pH versus limestone dosage for both pulverized limestone and
air-jet milled pulverized limestone is presented in Figure 22. The
-57-
-------
T/BLE XII
Average Raw Water Analysis
Proctor #2
Hollywood, Pennsylvania
pH
Total Iron
Ferrous Iron
Total Acidity
Free Mineral Acidity
Calcium
Magnesium
3.0
653 mg/1
445 mg/1
1560 mg/1 (as CaC03)
1740 mg/1 (as CaC03)
233 mg/1 (as CaC03)
168 mg/1 (as CaCO-j)
Total Solids
4110 mg/1
-58-
-------
FIGURE 22
PH VS LIMESTONE ADDITIONS
i
Ul
VO
I
Q.
AIR-JET MILLED
REGULAR PULVERIZED
III
500
1,000 1,500
LIMESTONE ADDITION- MG / I
2,000
-------
procedure for these tests was to add measured aliquots of a standard lime
stone slurry to 500 milliliter samples of the raw water and continuously
agitate for one-half hour before measuring the pH. Aliquots of the super-
natant collected after a one-half hour settling period were analyzed for
free mineral acidity. These results are presented in Figure 23. From
these tests, standard dosages of 1500 mg/1 for the air-jet milled pulver-
ized limestone and 1800 mg/1 for the pulverized limestone were selected.
Particle size analysis for these two materials were made by use of Coulter
Counter techniques. The results for the pulverized limestone were presented
in Table XI. The results for the air-jet milled pulverized limestone are
presented in Table XIII. The results would indicate the higher efficiencies
are associated with lower average particle size.
The setup of the designed experiment is presented in Table XIV and a dia-
gram of the system in Figure 5. The standard limestone dosage referred
to is the 1800 mg/1 dosage determined above. For purposes of the ex-
periment, the limestone dosage was varied higher and lower by 25 per
cent of the standard dosage. During these runs, the lime dosage was
adjusted to attempt to obtain an acceptable iron analysis on a filtered
sample of the clarifier feed. Due to the high ferrous iron content of
the raw water and insufficient aeration capacity in the pilot plant,
the resulting pH in the clarifier overflow was necessarily in the range
of pH 9.0 to 10.0. Use of sufficient aeration would probably result in
acceptable iron concentrations below pH 8.0. The data that was recorded
or calcualted for use in the statistical analysis were:
Level number
Raw flow rate - gallons per minute
Air flow rate - cubic feet per minute
Per cent sludge recirculation
Limestone dosage - pounds per gallon
Sludge volume as per cent of raw flow
Filtration rate - gallons per hour per square foot
Overflow velocity - feet per hour
Settling velocity - feet per hour
Solids loading - pounds per hour per square foot
Unit Relative Cost
Sludge solids concentration - per cent
-60-
-------
FIGURE 23
FFMA VS LIMESTONE ADDITION
1,200
CO
8
O
u
in
O
5
i
± 1,000
Q
Of
m
Z
O
LU
800
REGULAR PULVERIZED
600
I I I I > •
600
1,000 1,500
LIMESTONE ADDITION - MG s L
2,000
-61-
-------
TABLE XIII
Coulter Counter Analysis
of Air-jet Milled Pulverized Limestone
Weizht Distribution
Average
Volume
231997
173998
86999
43499
21750
10875
5437
2719
1359
680
340
170
85
42
21
11
Particle
Diam.
76.22
68.36
54.25
43.06
34.18
27.13
21.53
17.09
13.56
10.76
8.54
6.78
5.38
4.27
3.39
2.69
Differential
%
0.00
11.99
3.99
3.99
6.49
10.74
7.62
9.12
6.62
7.59
5.73
5.24
5.59
5.70
5.68
3.81
%
Less than
100.00
88.00
84.00
80.00
73.50
62.75
55.13
46.00
39.37
31.78
26.04
20.80
15.20
9.49
3.81
0.00
Number Distribution
Differential
%
0.00
0.00
0.00
0.01
0.03
0.11
0.15
0.37
0.54
1.24
1.88
3.44
7.34
14.98
29.82
40.03
%
Less than
100.00
99.99
99.98
99.97
99.94
99.83
99.67
99.30
98.75
97.51
95.63
92.18
84.84
69.85
40.03
0.00
Volume average diameter is 23.83 microns. Area average diameter is
10.07 microns. Length average diameter is 5.23 microns.
-62-
-------
TABLE XIV
Statistically Designed Experimental Program
Levels
Run
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
Raw
Feed Rate
J?pm
5
10
15
5
10
15
5
10
15
5
10
15
5
10
15
5
10
15
5
10
15
5
10
15
5
10
15
5
10
15
Aeration
Rate
cfm
0
10
17
0
17
10
0
17
10
0
17
10
10
0
17
10
0
17
10
0
17
17
10
0
17
10
0
17
10
0
Sludge
Recirculation
%
0
20
50
0
20
50
50
0
20
20
50
0
0
20
50
50
0
20
20
50
0
0
20
50
50
0
20
20
50
0
Limestone
Feed
-25%
Standard
+25%
-25
+25
Standard
Standard
-25
+25
+25
Standard
-25
+25
Standard
-25
-25
+25
Standard
Standard
-25
+25
Standard
-25
+25
+25
Standard
-25
-25
+25
Standard
-63-
-------
The first four items after level number were the controlled variables
in the experiment. The sludge volume was calculated from the flow rate
required to obtain a balance of filterable solids in and out of the
thickener. The filtration rate was measured during filterability tests
using the Johns-Manville 0.1 square foot rotary vacuum precoat test leaf,
Overflow velocity was calculated from the overflow rate and the cross-
sectional area of the clarification zone in the thickener. Settling
velocity was calculated from the relationship
Q(F - D)
R ~ PA
where R • settling rate - feet per hour
Q - solids feed rate - pounds per hour
F » feed concentration - pounds liquid/pound solids
D - sludge concentration - pounds liquid/pound solids
P « density of solution - pounds per cubic foot
A = cross-sectional area - square feet.
Solids loading was calculated based on the feed solids concentra-
tion, the overflow rate, and the cross-sectional area of the
clarification zone. To calculate the Unit Relative Cost, the cost
of equipment that would vary with different conditions was estimated.
This included the blowers required, the thickener, and the filter
unit. These costs were amortized on the basis of 20 year life with
straight-line depreciation. Cost of capital was neglected. A unit
cost computed from the amortization and the chemical costs were
calculated. The lowest cost was used as the basis, and the costs
at other conditions computed as a factor relative to it.
The statistical analysis of the data proudced the following
equation relating process variables to Unit Relative Cost (URC):
URC =• 1.667 + 0.02298 x (per cent sludge)
- 5.319 x (filtration rate, gal./ft2 - min)
+ 6.492 x 10~5 x (per cent recirculation)2
Eighty per cent of the total observed variation in the URC was
accounted for by this expression. Higher URC was associated with
higher volumes of sludge, higher recirculation rates, and lower
filtration rates. The data were examined to determine what
relationships might exist among them. The results were:
-64-
-------
1. Sludge solids concentration and filtration rate were inversely
related.
2. Sludge solids concentration and raw flow rate were inversely
related.
3. Raw flow was related with overflow velocity.
4. Raw flow was related with settling velocity.
5. Raw flow was related very closely with solids loading.
6. Sludge volume was related inversely with sludge solids" concen-
tration.
7. Sludge volume was related inversely with settling velocity.
8. Overflow velocity was related with settling velocity.
9. Overflow velocity was related with solids loading.
10. Settling velocity was related with solids loading.
The analytical data from each of the runs is presented in Tables XV.1
to XV.27. The iron reported in the clarifier feed stream was deter-
mined by analysis of a filtered sample to represent the unprecipitated
iron at this point in the process. The chemical usage efficiency for
the limestone was calculated as the acidity reduction in the aerator
over the dosage. The chemical usage efficiency for lime was similarly
computed based on acidity reduction between aerator overflow and
clarifier overflow. Due to the problem of supply of air-jet milled
pulverized limestone, pulverized limestone was used during the
twenty-seven levels of the designed experiment. Two additional runs
were made using the air-jet milled material. The analysis of these
runs is presented in Tables XVI.1 and XVI.2. A run was made using
lime only and the results are presented in Table XVII. One run at
the high flow rate was made using the standard limestone dosage with
lime and one milligram per liter of ATLASEP 1A1, a weakly anionic
polyelectrolyte. The results are presented in Table XVIII.
The effects of reducing the particle size distribution by air-jet
milling operationally appeared to offer significant advantages.
Comparing the first run using air-Jet milled material with the level
14 run, approximately 55 per cent less air-jet milled limestone gave
about the same neutralization results, indicating a considerably
greater efficiency from the air-Jet milled material. Better settling
characteristics due partially to a lower solids loading were obtained
with the finer material as indicated by the improved quality overflow
-65-
-------
TABLE XV.1
Level No. 1
Designed Conditions;
Raw Flow - 5 gal./min
Aeration - 0 cu ft/min
Recycle - 0 per cent
Limestone (Fraction of Standard)
- 0.75
Chemical Analysis (as mg/1)
pH
Total Iron
Ferrous Iron
Total Acidity
Free Mineral Acidity
Calcium
Magnesium
Filterable Solids
Total Solids
Total Alkalinity
Phenol Alkalinity
Solids Balance (as Ib/hr)
Flow Conditions
Clarifier Overflow, gal./min
Clarifier Underflow, gal./min
Sludge Recycle, gal./min
Clarifier Solids Loading, Ib/sq ft-hr
Chemical Usage Efficiencies
Feed, mg/1
Efficiency, per cent
Raw
2.9
637.0
413.0
1670.0
1700.0
190.0
170.0
3720.0
Aerator
Overflow
5.1
436.0
385.0
770.0
900.0
Clarifier
Feed
10.0
1.0
1.0
3963.0
Clarifier Clarifier
Overflow Underflow
10,2
6.0
0.0
1600.0
0.0
10208.0
3200.0
36.0
22.0
Filtrate
6.2
0.0
20.0
1590.0
0.0
3000.0
4.0
0.0
9.9
6.1
Operating
Equilibrium
3.8
1.2
0.0
0.29
Limestone
1320.0
70.4
3.0
1.9
0.0
0.23
Lime
1272.0
60.5
I
sO
-------
TABLE XV.2
Level No. 2
Designed Conditions;
Raw Flow - 10 gal./min
Aeration - 17 cu ft/min
Recycle - 20 per cent
Limestone (Fraction of Standard)
- 1.25
Chemical Analysis (as mg/1)
Total Iron
Ferrous Iron
Total Acidity
Free Mineral Acidity
Calcium
Magnesium
Filterable Solids
Total Solids
Total Alkalinity
Phenol Alkalinity
Solids Balance (as Ib/hr)
Flow Conditions
Clarifier Overflow, gal./min
Clarifier Underflow, gal./min
Sludge Recycle, gal./min
Clarifier Solids Loading, Ib/sq ft-hr
Chemical Usage Efficiencies
Feed, mg/1
Efficiency, per cent
Raw
2.9
564.0
419.0
1440.0
1690.0
230.0
160.0
3840.0
Aerator
Overflow
6.1
452.0
385.0
710.0
1680.0
Clarifier
Feed
9.8
0.0
0.0
3300.0
Clarifier
Overflow
10.3
2.0
0.0
1440.0
120.0
3120.0
48.0
32.0
Clarifier
Underflow Filtrate
6.6
1.0
5.0
1540.0
0.0
6250.0
2920.0
10.0
0.0
15.2
12.5
Operating
Equilibrium
6.0
4.0
0.9
0.39
Limestone
2304
42.5
5.1
4.8
0.9
0.33
Lime
1296
54.7
-------
TABLE XV. 3
Level No. 3
Designed Conditions:
Raw Flow - 15 gal./min
Aeration - 10 cu ft/min
Recycle - 50 per cent
Limestone (Fraction of Standard) - 1.00
Chemical Analysis (as mg/1)
PH
Total Iron
Ferrous Iron
Total Acidity
Free Mineral Acidity
Calcium
Magnesium
Filterable Solids
Total Solids
Total Alkalinity
Phenol Alkalinity
Solids Balance (as Ib/hr)
Flow Conditions
Clarifier Overflow, gal./min
Clarifier Underflow, gal./min
Sludge Recycle, gal./min
Clarifier Solids Loading, Ib/sq ft-hr
Chemical Usage Efficiencies
Feed, mg/1
Efficiency, per cent
Raw
3.0
590.0
446.0
1350.0
1350.0
250.0
220.0
0.0
Aerator
Overflow
6.0
430.0
279.0
890.0
1440.0
Clarifier
Feed
6.5
0.0
0.0
3240.0
Clarifier
Overflow
6.8
11.0
70.0
1340.0
230.0
0.0
0.0
Clarifier
Underflow Filtrate
6.8
1.0
20.0
1550.0
0.0
8440.0
0.0
0.0
20.2
Operating
11.5
3.5
1.6
0.73
Limestone
1728
26.6
0.0
Equilibrium
10.2
4.7
1.6
14.8
0.65
Lime
0.0
I
CO
-------
TABLE XV.4
Level No. 4
Designed Conditions;
Raw Flow - 5 gal./min
Aeration - 0 cu ft/min
Recycle - 50 per cent
Limestone (Fraction of Standard) - 1.00
Chemical Analysis (as mg/1)
pH
Total Iron
Ferrous Iron
Total Acidity
Free Mineral Acidity
Calcium
Magnesium
Filterable Solids
Total Solids
Total Alkalinity
Phenol Alkalinity
Solids Balance (as Ib/hr)
Flow Conditions
Clarifier Overflow, gal./min
Clarifier Underflow, gal./min
Sludge Recycle, gal./min
Clarifier Solids Loading, Ib/sq ft-hr
Chemical Usage Efficiencies
Feed, mg/1
Efficiency, per cent
Raw
3.0
626.0
480.0
1450.0
1450.0
290.0
210.0
4120.0
Aerator
Overflow
5.6
420.0
409.0
640.0
1296.0
Clarifier
Feed
8.2
1.0
0.0
4348.0
Clarifier
Overflow
9.4
5.0
0.0
1580.0
0.0
3280.0
0.0
0.0
Clarifier
Underflow Filtrate
7.0
1.0
30.0
1560.0
0.0
6976.0
3160.0
0.0
0.0
9.7
6.6
Operating
Equilibrium
3.1
1.9
0.9
0.26
Limes tone
1775
45.6
2
2
0
0
Lime
1152
55
.2
.7
.9
.19
.5
-------
TABLE XV.5
Level No. 5
Designed Conditions:
Raw Flow - 10 gal./min
Aeration - 17 cu ft/min
Recycle - 0 per cent
Limestone (Fraction of Standard)
- 0.75
Chemical Analysis (as mg/1)
PH
Total Iron
Ferrous Iron
Total Acidity
Free Mineral Acidity
Calcium
Magnesium
Filterable Solids
Total Solids
Total Alkalinity
Phenol Alkalinity
Solids Balance (as Ib/hr)
Flow Conditions
Clarifier Overflow, gal./min
Clarifier Underflow, gal./min
Sludge Recycle, gal./min
Clarifier Solids Loading, Ib/sq ft-hr
Chemical Usage Efficiencies
Feed, mg/1
Efficiency, per cent
Raw
2.7
660.0
444.0
1500.0
1650.0
290.0
210.0
3800.0
Aerator
Overflow
5.5
503.0
430.0
730.0
1644.0
Clarifier
Feed
10.6
1.0
0.0
3400.0
Clarifier
Overflow
9.7
22.0
0.0
1630.0
0.0
3480.0
0.0
0.0
Clarifier
Underflow Filtrate
7.9
1.0
30.0
1630.0
0.0
5788.0
3200.0
0.0
0.0
17.0
10.4
Operating
6.4
3.6
0.0
0.43
Limestone
1380
55.7
Equilibrium
4.1
5.8
0.0
0.27
Lime
1104
66.1
o
-------
TABLE XV.6
Level No. 6
Designed Conditions;
Raw Flow - 15 gal./min
Aeration - 10 cu ft/tnin
Recycle - 20 per cent
Limestone (Fraction of Standard)
- 1.25
Chemical Analysis (as mg/1)
pH
Total Iron
Ferrous Iron
Total Acidity
Free Mineral Acidity
Calcium
Magnesium
Filterable Solids
Total Solids
Total Alkalinity
Phenol Alkalinity
Solids Balance (as Ib/hr)
Flow Conditions
Clarifier Overflow, gal./min
Clarifier Underflow, gal./min
Sludge Recycle, gal./min
Clarifier Solids Loading, Ib/sq ft-hr
Chemical Usage Efficiencies
Feed, mg/1
Efficiency, per cent
Raw
3.1
675.0
441.0
1450.0
1600.0
270.0
210.0
3800.0
Aerator
Overflow
6.4
460.0
408.0
820.0
1672.0
Clarifier
Feed
8.6
1.0
0.0
3348.0
Clarifier
Overflow
9.0
9.0
0.0
1560.0
70.0
3400.0
0.0
0.0
Clarifier
Underflow Filtrate
8.5
1.0
10.0
1620.0
60.0
7992.0
3360.0
0.0
0.0
21.9
24.8
Operating
Equilibrium
8.8
6.2
1.4
0.58
Limes Cone
2256
27.9
9.5
5.4
1.4
0.63
Lime
984
83.3
-------
Level No. 7
TABLE XV.7
Designed Conditions:
Raw Flow - 5 gal./min
Aeration - 0 cu ft/min
Recycle - 20 per cent
Limestone (Fraction of Standard)
- 1.25
Chemical Analysis (as mg/1)
pH
Total Iron
Ferrous Iron
Total Acidity
Free Mineral Acidity
Calcium
Magnesium
Filterable Solids
Total Solids
Total Alkalinity
Phenol Alkalinity
Solids Balance (as Ib/hr)
Flow Conditions
Clarifier Overflow, gal./min
Clarifier Underflow, gal./min
Sludge Recycle, gal./min
Clarifier Solids Loading, Ib/sq ft-hr
Chemical Usage Efficiencies
Feed, mg/1
Efficiency, per cent
Raw
3.0
697.0
440.0
1490.0
1670.0
280.0
310.0
3800.0
Aerator
Overflow
5.7
468.0
403.0
830.0
1360.0
Clarifier
Feed
9.6
1.0
0.0
5252.0
Clarifier
Overflow
8.3
12.0
0.0
1590.0
270.0
3360.0
0.0
0.0
Clarifier
Underflow Filtrate
8.5
1.0
40.0
1690.0
0.0
12832.0
3600.0
0.0
0.0
11.6
12.2
Operating
3.1
1.9
0.4
0.32
Limestone
1752
37.6
Equilibrium
3.1
1.8
0.4
0.33
Lime
960
86.4
I
CM
-------
TABLE XV.8
I
-J
U)
Level No. 8
Designed Conditions:
Raw Flow - 10 gal./min
Aeration - 10 cu ft/min
Recycle - 50 per cent
Limestone (Fraction of Standard) - 1.00
Chemical Analysis (as mg/1)
PH
Total Iron
Ferrous Iron
Total Acidity
Free Mineral Acidity
Calcium
Magnesium
Filterable Solids
Total Solids
Total Alkalinity
Phenol Alkalinity
Solids Balance (as Ib/hr)
Flow Conditions
Clarifier Overflow, gal./min
Clarifier Underflow, gal./min
Sludge Recycle, gal./min
Clarifier Solids Loading, Ib/sq ft-hr
Chemical Usage Efficiencies
Feed, mg/1
Efficiency, per cent
Raw
3.0
627.0
427.0
1490.0
1650.0
270.0
250.0
3020.0
Aerator
Overflow
6.0
452.0
407.0
850.0
1980.0
Clarifier
Feed
9.3
0.0
0.0
5976.0
Clarifier
Overflow
9.9
5.0
0.0
1650.0
10.0
2920.0
0.0
0.0
Clarifier
Underflow Filtrate
8.6
0.0
20.0
1630.0
10.0
7390.0
3280.0
0.0
0.0
28.5
14.8
Operating
Equilibrium
6.0
4.0
2.0
0.70
Limestone
1775
36.0
2
7
2
0
Li me
899
94
.2
.7
.0
.26
.4
-------
TABLE XV.9
Level No. 9
Designed Conditions:
Raw Flow - 15 gal./rain
Aeration - 10 cu ft/min
Recycle - 0 per cent
Limestone (Fraction of Standard)
- 0.75
Chemical Analysis (as mg/1)
PH
Total Iron
Ferrous Iron
Total Acidity
Free Mineral Acidity
Calcium
Magnesium
Filterable Solids
Total Solids
Total Alkalinity
Phenol Alkalinity
Solids Balance (as Ib/hr)
Flow Conditions
Clarifier Overflow, gal./min
Clarifler Underflow, gal./min
Sludge Recycle, gal./min
Clarifier Solids Loading, Ib/sq ft-hr
Chemical Usage Efficiencies
Feed, mg/1
Efficiency, per cent
Raw
3.0
575.0
424.0
1490.0
1680.0
280.0
220.0
3800.0
Aerator
Overflow
4.9
445.0
421.0
820.0
1328.0
Clarifier
Feed
9.9
1.0
0.0
3896.0
Clarifier
Overflow
9.4
12.0
0.0
1610.0
80.0
3360.0
0.0
0.0
Clarifier
Underflow Filtrate
8.3
0.0
0.0
1690.0
10.0
5696.0
3360.0
0.0
0.0
i
sf
r-
1
29.3
17.1
Operating
9.0
6.0
0.0
0.69
Limestone
1232
54.3
Equilibrium
4.7
10.2
0.0
0.36
Lime
-------
TABLE XV.10
Ln
I
Level No. 10
Designed Conditions:
Raw Flow - 5 gal./min
Aeration - 10 cu ft/min
Recycle •* 0 per cent
Limestone (Fraction of Standard)
- 1.25
Chemical Analysis (as mg/1)
PH
Total Iron
Ferrous Iron
Total Acidity
Free Mineral Acidity
Calcium
Magnesium
Filterable Solids
Total Solids
Total Alkalinity
Phenol Alkalinity
Solids Balance (as Ib/hr)
Flow Conditions
Clarifier Overflow, gal./min
Clarifier Underflow, gal./min
Sludge Recycle, gal./min
Clarifier Solids Loading, Ib/sq ft-hr
Chemical Usage Efficiencies
Feed, mg/1
Efficiency, per cent
Raw
3.0
536.0
430.0
1510.0
1680.0
290.0
180.0
3840.0
Aerator
Overflow
6.2
417.0
362.0
810.0
1520.0
Clarifier
Feed
9.4
0.0
0.0
3832.0
Clarifier
Overflow
9.5
4.0
20.0
1580.0
60.0
3320.0
0.0
0.0
Clarifier
Underflow Filtrate
9.1
0.0
30.0
1620.0
0.0
9476.0
3160.0
0.0
0.0
9.6
8.1
Operating
Equilibrium
3.3
1.7
0.0
0.25
Limestone
2064
33.9
2.
2.
0.
0,
Lime
696
100,
.9
.0
.0
.22
,0
-------
TABLE XV.11
Level No. 11
Designed Conditions:
Raw Flow - 10 gal./min
Aeration - 0 cu ft/min
Recycle - 20 per cent
Limestone (Fraction of Standard) - 1.00
Chemical Analysis (as mg/1)
pH
Total Iron
Ferrous Iron
Total Acidity
Free Mineral Acidity
Calcium
Magnesium
Filterable Solids
Total Solids
Total Alkalinity
Phenol Alkalinity
Solids Balance (as Ib/hr)
Flow Conditions
Clarifier Overflow, gal./min
Clarifier Underflow, gal./min
Sludge Recycle, gal./min
Clarifier Solids Loading, Ib/sq ft-hr
Chemical Usage Efficiencies
Feed, mg/1
Efficiency, per cent
Raw
3.0
675.0
374.0
1420.0
1690.0
300.0
150.0
3880.0
Aerator
Overflow
5.5
385.0
348.0
520.0
2000.0
Clarifier
Feed
8.9
1.0
0.0
4470.0
Clarifier
Overflow
7.8
10.0
0.0
1600.0
50.0
3360.0
99.0
0.0
Clarifier
Underflow Filtrate
7.6
0.0
0.0
1680.0
80.0
6000.0
3400.0
0.0
0.0
21.8
12.0
Operating
6.0
4.0
0.8
0.53
Limestone
1704
52.8
Equilibrium
2.7
7.2
0.8
0.24
i
vO
-------
TABLE XV.12
Level No. 12
Designed Conditions;
Raw Flow - 15 gal./min
Aeration - 17 cu ft/min
Recycle - 50 per cent
Limestone (Fraction of Standard) - 0.75
Chemical Analysis (as mg/1)
PH
Total Iron
Ferrous Iron
Total Acidity
Free Mineral Acidity
Calcium
Magnesium
Filterable Solids
Total Solids
Total Alkalinity
Phenol Alkalinity
Solids Balance (as Ib/hr)
Flow Conditions
Clarifier Overflow, gal./min
Clarifier Underflow, gal./min
Sludge Recycle, gal./min
Clarifier Solids Loading, Ib/sq ft-hr
Chemical Usage Efficiencies
Feed, mg/1
Efficiency, per cent
Raw
2.9
619.0
374.0
1430.0
1420.0
260.0
160.0
3920.0
Aerator
Overflow
4.9
402.0
357.0
640.0
2240.0
Clartfier
Feed
10.8
1.0
0.0
3480.0
Clarif ier
Overflow
8.5
2.0
0.0
1560.0
40.0
4560.0
24.0
0.0
Clarifier
Underflow Filtrate
7.8
1.0
40.0
1670.0
20.0
5410.0
3680.0
10.0
0.0
23.2
16.3
Operating
Equilibrium
9.0
6.0
3.0
0.61
Limestone
1328
59.4
6.4
8.5
3.0
0.44
Lime
1000
64.0
-------
Level No. 13
TABLE XV.13
Designed Conditions:
Raw Flow - 5 gal./min
Aeration - 10 cu ft/min
Recycle - 50 per cent
Limestone (Fraction of Standard)
- 0.75
Chemical Analysis (as mg/1)
pH
Total Iron
Ferrous Iron
Total Acidity
Free Mineral Acidity
Calcium
Magnesium
Filterable Solids
Total Solids
Total Alkalinity
Phenol Alkalinity
Solids Balance (as Ib/hr)
Flow Conditions
Clarifier Overflow, gal./min
Clarifier Underflow, gal./min
Sludge Recycle, gal./min
Clarifier Solids Loading, Ib/sq ft-hr
Chemical Usage Efficiencies
Feed, mg/1
Efficiency, per cent
Raw
2.9
564.0
385.0
1450.0
1490.0
260.0
80.0
5000.0
Aerator
Overflow
5.6
0.0
357.0
510.0
2800.0
Clarifier
Feed
10.9
1.0
0.0
5760.0
Clarifier
Overflow
10.1
1.0
20.0
1540.0
40.0
3650.0
20.0
8.0
Clarifier
Underflow Filtrate
7.5
0.0
40.0
1550.0
0.0
6800.0
3000.0
8.0
0.0
13.9
6.8
Operating
3.0
2.0
1.0
0,34
Limestone
1320
71.2
Equilibrium
0.9
4.0
1.0
0.10
Lime
744
68.5
I
00
-------
TABLE XV.14
Level No. 14
Designed Conditions:
Raw Flow - 10 gal./min
Aeration - 0 cu ft/min
Recycle - 0 per cent
Limestone (Fraction of Standard)
- 1.25
Chemical Analysis (as mg/1)
pH
Total Iron
Ferrous Iron
Total Acidity
Free Mineral Acidity
Calcium
Magnesium
Filterable Solids
Total Solids
Total Alkalinity
Phenol Alkalinity
Solids Balance (as Ib/hr)
Flow Conditions
Clarifier Overflow, gal./min
Clarifier Underflow, gal./min
Sludge Recycle, gal./min
Clarifier Solids Loading, Ib/sq ft-hr
Chemical Usage Efficiencies
Feed, mg/1
Efficiency, per cent
Raw
2.9
705.0
441.0
1680.0
1890.0
220.0
80.0
4680.0
Aerator
Overflow
5.5
447.0
408.0
640.0
1600.0
Clarifier
Feed
8.0
8.0
8.0
2960.0
Clarifier
Overflow
7.6
10.0
0.0
1710.0
150.0
3640.0
88.0
0.0
Clarifier
Underflow Filtrate
7.7
0.0
0.0
1690.0
200.0
5200.0
3720.0
64.0
4.0
14.8
14.8
Operating
Equilibrium
4.3
5.7
0.0
0.25
Limestone
2256
46.0
4.2
5.7
0.0
0.25
Lime
1008
63.4
-------
Level No. 15
TABLE XV.15
Designed Conditions:
Raw Flow - 15 gal./rain
Aeration - 17 cu ft/min
Recycle - 20 per cent
Limestone (Fraction of Standard) - 1.00
Chemical Analysis (as mg/1)
PH
Total Iron
Ferrous Iron
Total Acidity
Free Mineral Acidity
Calcium
Magnesium
Filterable Solids
Total Solids
Total Alkalinity
Phenol Alkalinity
Solids Balance (as Ib/hr)
Flow Conditions
Clarifier Overflow, gal./min
Clarifier Underflow, gal./min
Sludge Recycle, gal./min
Clarifier Solids Loading, Ib/sq ft-hr
Chemical Usage Efficiencies
Feed, mg/1
Efficiency, per cent
Raw
2.9
610.0
441.0
1700.0
1840.0
280.0
110.0
4160.0
Aerator
Overflow
5.2
513.0
430.0
720.0
1520.0
Clarifier
Feed
7.5
12.0
12.0
2360.0
Clarifier
Overflow
7.9
3.0
10.0
1670.0
160.0
3600.0
28.0
0.0
Clarifier
Underflow Filtrate
7.2
1.0
10.0
1670.0
200.0
4080.0
3600.0
30.0
0.0
o
OO
1
16.3
22.5
Operating
4.0
11.0
1.6
0.18
Limestone
1800
54.4
Equilibrium
6.9
8.0
1.6
0.32
Lime
808
89.1
-------
TABLE XV.16
i
00
Level No. 16
Designed Conditions:
Raw Flow - 5 gal./min
Aeration - 10 cu ft/min
Recycle - 20 per cent
Limestone (Fraction of Standard) - 1.00
Chemical Analysis (as mg/1)
PH
Total Iron
Ferrous Iron
Total Acidity
Free Mineral Acidity
Calcium
Magnesium
Filterable Solids
Total Solids
Total Alkalinity
Phenol Alkalinity
Solids Balance (as Ib/hr)
Flow Conditions
Clarifier Overflow, gal./min
Clarifier Underflow, gal./min
Sludge Recycle, gal./min
Clarifier Solids Loading, Ib/sq ft-hr
Chemical Usage Efficiencies
Feed, mg/1
Efficiency, per cent
Raw
2.9
580.0
446.0
1730.0
1910.0
200.0
140.0
4200.0
Aerator
Overflow
5.8
486.0
424.0
710.0
1300.0
Clarifier
Feed
10.1
0.0
0.0
4120.0
Clarifier
Overflow
7.3
7.0
20.0
1660.0
120.0
3560.0
26.0
0.0
Clarifier
Underflow Filtrate
8.4
0.0
20.0
1800.0
100.0
7528.0
3640.0
24.0
2.0
9.5
6.8
Operating
Equilibrium
3.2
1.8
0.5
0.26
Limes tone
1799
56,6
2.4
2.5
0.5
0.20
Lime
528
100
-------
Level No. 17
TABLE XV.17
Designed Conditions:
Raw Flow - 10 gal./min
Aeration - 0 cu ft/min
Recycle - 50 per cent
Limestone (Fraction of Standard)
- 0.75
Chemical Analysis (as mg/1)
pH
Total Iron
Ferrous Iron
Total Acidity
Free Mineral Acidity
Calcium
Magnesium
Filterable Solids
Total Solids
Total Alkalinity
Phenol Alkalinity
Solids Balance (as Ib/hr)
Flow Conditions
Clarifier Overflow, gal./min
Clarifier Underflow, gal./min
Sludge Recycle, gal./min
Clarifier Solids Loading, Ib/sq ft-hr
Chemical Usage Efficiencies
Feed, mg/1
Efficiency, per cent
Raw
2.9
591.0
446.0
1640.0
1820.0
250.0
90.0
4120.0
Aerator
Overflow
4.8
530.0
446.0
820.0
1692.0
Clarifier
Feed
7.6
0.0
0.0
3240.0
Clarifier
Overflow
7.3
18.0
0.0
1670.0
210.0
3640.0
94.0
0.0
Clarifier
Underflow Filtrate
7.1
9.0
0.0
1720.0
160.0
3592.0
3640.0
99.0
0.0
i
CM
CO
1
15.6
12.9
Operating
2.8
7.2
3.5
0.17
Limestone
1356
60.4
Equilibrium
1.2
8.7
3.5
0.08
Lime
-------
TABLE XV.18
t
oo
Level No. 18
Designed Conditions:
Raw Flow - 15 gal./min
Aeration - 17 cu ft/min
Recycle - 0 per cent
Limestone (Fraction of Standard)
- 1.25
Chemical Analysis (as me/1)
pH
Total Iron
Ferrous Iron
Total Acidity
Free Mineral Acidity
Calcium
Magnesium
Filterable Solids
Total Solids
Total Alkalinity
Phenol Alkalinity
Solids Balance (as Ib/hr)
Flow Conditions
Clarifier Overflow, gal./min
Clarifier Underflow, gal./min
Sludge Recycle, gal./min
Clarifier Solids Loading, Ib/sq ft-hr
Chemical Usage Efficiencies
Feed, mg/1
Efficiency, per cent
Raw
2.9
591.0
453.0
1660.0
1860.0
250.0
120.0
4240.0
Aerator
Overflow
5.2
525.0
446.0
750.0
2340.0
Clarifier
Feed
9.9
0.0
0.0
3100.0
Clarifier
Overflow
8.2
18.0
30.0
1640.0
190.0
3640.0
44.0
0.0
Clarifier
Underflow Filtrate
8.4
0.0
10.0
1730.0
160.0
3562.0
3640.0
32.0
4.0
23.3
16.1
Operating
Equilibrium
6.0
9.0
0.0
0.36
Limestone
2256
40.3
1.9
13.0
0.0
0.11
Lime
800
93.7
-------
TABLE XV.19
Level No. 19
Designed Conditions:
Raw Flow - 5 gal./min
Aeration - 17 cu ft/min
Recycle - 0 per cent
Limestone (Fraction of Standard) - 1.00
Chemical Analysis (as mg/1)
PH
Total Iron
Ferrous Iron
Total Acidity
Free Mineral Acidity
Calcium
Magnesium
Filterable Solids
Total Solids
Total Alkalinity
Phenol Alkalinity
Solids Balance (as Ib/hr)
Flow Conditions
Clarifier Overflow, gal./min
Clarifier Underflow, gal./min
Sludge Recycle, gal./min
Clarifier Solids Loading, Ib/sq ft-hr
Chemical Usage Efficiencies
Feed, mg/1
Efficiency, per cent
Raw
2.9
591.0
458.0
1680.0
1910.0
174.0
152.0
4120.0
Aerator
Overflow
5.9
480.0
419.0
700.0
1764.0
Clarifier
Feed
6.9
18.0
0.0
3004.0
Clarifier
Overflow
6.7
22.0
130.0
1630.0
140.0
3480.0
16.0
0.0
Clarifier
Underflow Filtrate
8.3
0.0
30.0
1800.0
80.0
10832.0
3640.0
18.0
2.0
i
oo
7.5
9.2
Operating
3.3
1.7
0.0
0.19
Limestone
1799
54.4
Equilibrium
3.6
1.3
0.0
0.21
Lime
528
100.0
-------
TABLE XV.20
i
CO
Level No. 20
Designed Conditions:
Raw Flow - 10 gal./min
Aeration - 10 cu ft/min
Recycle - 20 per cent
Limestone (Fraction of Standard)
- 0.75
Chemical Analysis (as mg/1)
pH
Total Iron
Ferrous Iron
Total Acidity
Free Mineral Acidity
Calcium
Magnesium
Filterable Solids
Total Solids
Total Alkalinity
Phenol Alkalinity
Solids Balance (as Ib/hr)
Flow Conditions
Clarifier Overflow, gal./min
Clarifier Underflow, gal./min
Sludge Recycle, gal./min
Clarifier Solids Loading, Ib/sq ft-hr
Chemical Usage Efficiencies
Feed, mg/1
Efficiency, per cent
Raw
2.9
616.0
458.0
1650.0
1970.0
220.0
120.0
4280.0
Aerator
Overflow
5.2
531.0
442.0
750.0
1368.0
Clarifier
Feed
7.6
120.0
0.0
2780.0
Clarifier
Overflow
9.4
5.0
10.0
1730.0
80.0
3440.0
42.0
14.0
Clarifier
Underflow Filtrate
8.6
0.0
30.0
1780.0
50.0
4884.0
3320.0
20.0
4.0
12.4
13.2
Operating
Equilibrium
4.6
5.4
1.4
0.25
Limestone
1356
66.3
4.8
5.1
1.4
0.26
Lime
744
100.0
-------
TABLE XV.21
Level No. 21
Designed Conditions:
Raw Flow - 15 gal./min
Aeration - 0 cu ft/min
Recycle - 50 per cent
Limestone (Fraction of Standard)
- 1.25
Chemical Analysis (as mg/1)
pH
Total Iron
Ferrous Iron
Total Acidity
Free Mineral Acidity
Calcium
Magnesium
Filterable Solids
Total Solids
Total Alkalinity
Phenol Alkalinity
Solids Balance (as Ib/hr)
Flow Conditions
Clarifier Overflow - gal./min
Clarifier Underflow - gal./min
Sludge Recycle - gal./min
Clarifier Solids Loading - Ib/sq ft-hr
Chemical Usage Efficiencies
Feed, mg/1
Efficiency, per cent
Raw
3.2
745.0
490.0
1580.0
1840.0
180.0
180.0
4336.0
Aerator
Overflow
5.6
690.0
490.0
450.0
1520.0
Clarifier
Feed
6.7
178.0
0.0
2732.0
Clarifier
Overflow
6.7
28.0
0.0
1660.0
140.0
3932.0
90.0
0.0
Clarifier
Underflow Filtrate
6.8
30.0
0.0
1726.0
294.0
5552.0
3940.0
56.0
0.0
i
sO
CO
1
16.7
16.7
Operating
9.0
6.0
2.7
0.48
Limestone
2200
51.3
Equilibrium
8.9
6.0
2.7
0.48
Lime
832
54.0
-------
TABLE XV.22
oo
-vl
I
Level No. 22
Designed Conditions;
Raw Flow - 5 gal./rain
Aeration - 17 cu ft/min
Recycle - 50 per cent
Limestone (Fraction of Standard)
- 1.25
Chemical Analysis (as mg/1)
pH
Total Iron
Ferrous Iron
Total Acidity
Free Mineral Acidity
Calcium
Magnesium
Filterable Solids
Total Solids
Total Alkalinity
Phenol Alkalinity
Solids Balance (as Ib/hr)
Flow Conditions
Clarifier Overflow, gal./min
Clarifier Underflow, gal./min
Sludge Recycle, gal./min
Clarifier Solids Loading, Ib/sq ft-hr
Chemical Usage Efficiencies
Feed, mg/1
Raw
3.0
692.0
510.0
1550.0
1850.0
180.0
160.0
4524.0
Aerator
Overflow
5.7
812.0
458.0
2056.0
Clarifier
Feed
9.2
0.0
0.0
3900.0
Clarifier
Overflow
8.3
2.0
70.0
1720.0
100.0
3593.0
12.0
4.0
Clarifier
Underflow Filtrate
8.3
0.0
70.0
1800.0
170.0
7236.0
3972.0
14.0
0.0
8.1
7.2
Operating
3.0
2.0
1.0
0.23
Limes tone
2280
Equilibrium
2.7
2.2
1.0
0.21
Lime
648
-------
Level No. 23
TABLE XV.23
Designed Conditions:
Raw Flow - 10 gal./min
Aeration - 10 cu ft/min
Recycle - 0 per cent
Limestone (Fraction of Standard) - 1.00
Chemical Analysis (as mg/1)
pH
Total Iron
Ferrous Iron
Total Acidity
Free Mineral Acidity
Calcium
Magnesium
Filterable Solids
Total Solids
Total Alkalinity
Phenol Alkalinity
Solids Balance (as Ib/hr)
Flow Conditions
Clarifier Overflow, gal./min
Clarifier Underflow, gal./min
Sludge Recycle, gal./min
Clarifier Solids Loading, Ib/sq ft-hr
Chemical Usage Efficiencies
Feed, mg/1
Efficiency, per cent
Raw
2.9
683.0
527.0
1590.0
1870.0
190.0
120.0
4256.0
Aerator
Overflow
5.4
855.0
490.0
250.0
1756.0
Clarifier
Feed
9.1
1.0
0.0
3208.0
Clarifier
Overflow
7.6
12.0
50.0
1720.0
130.0
3576.0
12.0
0.0
Clarifier
Underflow Filtrate
7.4
1.0
40.0
1820.0
110.0
8096.0
3668.0
10.0
0.0
i
oo
CO
'
16.1
24.7
Operating
3.9
6.1
0.0
0.24
Limestone
1799
74.4
Equilibrium
6.0
3.9
0.0
0.38
Lime
840
29.7
-------
TABLE XV.24
i
00
vO
I
Level No. 24
Designed Conditions;
Raw Flow - 15 gal./min
Aeration - 0 cu ft/mtn
Recycle - 20 per cent
Limestone (Fraction of Standard)
- 0.75
Chemical Analysis (as mg/1)
pH
Total Iron
Ferrous Iron
Total Acidity
Free Mineral Acidity
Calcium
Magnesium
Filterable Solids
Total Solids
Total Alkalinity
Phenol Alkalinity
Solids Balance (as Ib/hr)
Flow Conditions
Clarifier Overflow, gaL/min
Clarifier Underflow, gal./min
Sludge Recycle, gal./min
Clarifier Solids Loading, Ib/sq ft-hr
Chemical Usage Efficiencies
Feed, mg/1
Efficiency, per cent
Raw
2.9
849.0
505.0
1620.0
1880.0
170.0
130.0
4372.0
Aerator
Overflow
4.9
818.0
504.0
680.0
2988.0
Clarifier
Feed
7.2
50.0
0.0
2852.0
Clarifier
Overflow
7.0
50.0
70.0
1580.0
210.0
3844.0
9.0
0.0
Clarifier
Underflow Filtrate
7.3
5.0
0.0
2220.0
0.0
4092.0
3768.0
9.0
0.0
20.7
20.5
Operating
5.0
10.0
1.1
0.28
Limestone
1360
69.1
Equilibrium
4.8
10.1
1.1
0.27
Lime
1008
67.4
-------
Level No. 25
TABLE XV.25
Designed Conditions:
Raw Flow - 5 gal./min
Aeration - 17 cu ft/min
Recycle - 20 per cent
Limestone (Fraction of Standard)
- 0.75
Chemical Analysis (as mg/1)
pH
Total Iron
Ferrous Iron
Total Acidity
Free Mineral Acidity
Calcium
Magnesium
Filterable Solids
Total Solids
Total Alkalinity
Phenol Alkalinity
Solids Balance (as Ib/hr)
Flow Conditions
Clarifier Overflow, gal./min
Clarifier Underflow, gal./min
Sludge Recycle, gal./min
Clarifier Solids Loading, Ib/sq ft-hr
Chemical Usage Efficiencies
Feed, mg/1
Efficiency, per cent
Raw
3.0
832.0
504.0
1600.0
1890.0
220.0
200.0
4492.0
Aerator
Overflow
5.4
755.0
625.0
670.0
1704.0
Clarifier
Feed
10.1
1.0
0.0
3416.0
Clarifier
Overflow
9.5
2.0
30.0
2270.0
180.0
3624.0
20.0
6.0
Clarifier
Underflow Filtrate
8.2
1.0
90.0
2360.0
60.0
4912.0
3360.0
18.0
0.0
o
o\
1
8.1
7.6
Operating
1.9
3.1
0.6
0.12
Limestone
1320
70.4
Equilibrium
1.6
3.3
0.6
0.11
Lime
840
79.7
-------
TABLE XV.26
I
V0
Level No. 26
Designed Conditions:
Raw Flow - 10 gal./min
Aeration - 10 cu ft/min
Recycle - 50 per cent
Limestone (Fraction of Standard)
- 1.25
Chemical Analysis (as mg/1)
PH
Total Iron
Ferrous Iron
Total Acidity
Free Mineral Acidity
Calcium
Magnesium
Filterable Solids
Total Solids
Total Alkalinity
Phenol Alkalinity
Solids Balance (as Ib/hr)
Flow Conditions
Clarifier Overflow, gal./min
Clarifier Underflow, gal./min
Sludge Recycle, gal./min
Clarifier Solids Loading, Ib/sq ft-hr
Chemical Usage Efficiencies
Feed, mg/1
Efficiency, per cent
Raw
3.1
780.0
513.0
1540.0
1800.0
170.0
200.0
4300.0
Aerator
Overflow
6.0
725.0
500.0
370.0
1328.0
Clarifier
Feed
11.3
8.0
0.0
4024.0
Clarifier
Overflow
9.4
1.0
40.0
2300.0
260.0
3436.0
20.0
8.0
Clarifier
Underflow Filtrate
8.4
0.0
50.0
2300.0
250.0
5356.0
3486 . 0
12.0
1.0
17.7
16.6
Operating
Equilibrium
3.8
6.2
3.6
0.30
Limestone
2256
51.8
3.3
6.6
3.6
0.26
Lime
971
38.0
-------
TABLE XV.27
Level No. 27
Designed Conditions:
Raw Flow - 15 gal./rain
Aeration - 0 cu ft/min
Recycle - 0 per cent
Limestone (Fraction of Standard) - 1.00
Chemical Analysis (as mg/1)
pH
Total Iron
Ferrous Iron
Total Acidity
Free Mineral Acidity
Calcium
Magnesium
Filterable Solids
Total Solids
Total Alkalinity
Phenol Alkalinity
Solids Balance (as Ib/hr)
Flow Conditions
Clarifier Overflow, gal./min
Clarifier Underflow, gal./min
Sludge Recycle, gal./min
Clarifier Solids Loading, Ib/sq ft-hr
Chemical Usage Efficiencies
Feed, mg/1
Efficiency, per cent
Raw
3.0
830.0
480.0
1600.0
1830.0
250.0
190.0
4196.0
Aerator
Overflow
5.2
717.0
497.0
420.0
912.0
Clarifier
Feed
7.2
55.0
0.0
3520.0
Clarifier
Overflow
7.4
55.0
30.0
2150.0
320.0
3860.0
90.0
0.0
Clarifier
Underflow Filtrate
7.0
10.0
0.0
2440.0
350.0
7088.0
3920.0
84.0
0.0
26.4
20.2
Operating
9.3
5.7
0.0
0.64
Limestone
1800
65.5
Equilibrium
7.5
7.4
0.0
0.52
Lime
880
47.7
I
CM
-------
I
vO
u>
I
TABLE XVI. 1
Air-jet Milled Pulverized Limestone
Designed Conditions: Raw Flow
Aeration
Recycle
Limestone
Chemical Analysis (as mg/1)
pH
Total Iron
Ferrous Iron
Total Acidity
Free Mineral Acidity
Calcium
Magnesium
Filterable Solids
Total Solids
Total Alkalinity
Phenol Alkalinity
Solids Balance (as Ib/hr)
Flow Conditions
Clarifier Overflow, gal/min
Clarifier Underflow, gal/min
Sludge Recycle, gal/min
- 10 gal/min
- 0 cu ft/min
0 per cent
(Fraction of Standard) - 0.75
Raw Aerator Clarifier
Overflow Feed
3.1 5.6 7.6
620.0
382.0
1700.0
1700.0
208.0
252.0
952.0 1180,0
4000.0
5.9
Operating
7.8
2.2
0.0
Clarifier Solids Loading, Ib/sq ft-hr 0.18
Chemical Usage
Feed, mg/1
Limestone
1020
Clarifier Clarifier
Overflow Underflow
8.9
4.0
0.0
1640.0
0.0
11240.0
3400.0
40.0
2.0
12.4
Equilibrium
8.9
1..0
0.0
0.20
Lime
118ft
Filtrate
7.6
1.0
0.0
1520.0
40.0
3200.0
18.0
0.0
-------
TABLE XVI.2
Air-jet Milled Pulverized" Limestone
Designed Conditions:
Raw Flow - 15 gal./min
Aeration - 0 cu ft/min
Recycle - 0 per cent
Limestone (Fraction of Standard) - 1.00
Chemical Analysis (as mg/1)
pH
Total Iron
Ferrous Iron
Total Acidity
Free Mineral Acidity
Calcium
Magnesium
Filterable Solids
Total Solids
Total Alkalinity
Phenol Alkalinity
Solids Balance (as Ib/hr)
Flow Conditions
Clarifier Overflow, gal./min
Clarlfler Underflow, gal./min
Sludge Recycle, gal./min
Clarlfler Solids Loading, Ib/sq ft-hr
Chemical Usage
Feed, mg/1
Raw
2.9
676.0
408.0
1680.0
1700.0
250.0
80.0
4400.0
Aerator
Overflow
5.7
385.0
374.0
1340.0
Clarifier
Feed
9.1
1.0
0.0
3580.0
Clarifier
Overflow
7.0
55.0
0.0
1600.0
80.0
3480.0
99.0
0.0
Clarifier Filtrate
Underflow
7.7
0.0
0.0 ^
o>
i
1490.0
120.0
10000.0
3360.0
32.0
0.0
26.9
15.0
Operating
12.0
3.0
0.0
0.85
Limestone
1504
Equilibrium
9.6
5.3
0.0
0.68
Lime
968
-------
TABLE
Lime
XVII
Only
Designed Conditions: Raw Flow - 10 gal/min
Aeration - 0 cu ft
Recycle -
Chemical Analysis (as mg/1)
pH
Total Iron
Ferrous Iron
Total Acidity
Free Mineral Acidity
Calcium
Magnesium
Filterable Solids
Total Solids
Total Alkalinity
Phenol Alkalinity
Solids Balance (as Ib/hr)
Flow Conditions
Clarifier Overflow, gal/min
Clarifier Underflow, gal/min
Sludge Recycle, gal/min
Clarifier Solids Loading, Ib/sq
Chemical Usage
Feed, mg/1
0 per cent
Raw
3.0
561.0
392.0
1530.0
1890.0
130.0
300.0
4040.0
ft-hr
Clarifier
Feed
8.7
55.0
0.0
1960.0
9.8
Operating
5.0
5.0
0.0
0.19
Limestone
0.0
Clarifier Clarifier Filtrate
Overflow Underflow
7.0 7.0
55.0 0.0
0.0
1660.0
0.0
2700.0
3750.0
14.0
0.0
6.8
Equilibrium
2.7
7.2
0.0
0. 10
Lime
1512
-------
TABLE XVIII
Polyelectrolyte Run
Designed Conditions: Raw Flow -
Aeration -
Recycle -
Limestone
Chemical Analysis (as mg/1)
PH
Total Iron
Filterable Solids
Solids Balance (as Ib/hr)
Flow Conditions
Clarifier Overflow, gal./min
Clarifier Underflow, gal. /mitt
Sludge Recycle, gal./min
15 gal./min
17 cu ft/min
0 per cent
(Fraction of Standard) -
Aerator Clarifier
Overflow Feed
5.1 8.9
55.0
2596.0
19.5
Operating
9.0
6.0
0.0
Clarifier Solids Loading, Ib/sq ft-hr 0.46
Chemical Usage
Feed, mg/1
Limestone
1800
1.00
Clarifier Clarifier
Overflow Underflow
8.0
15.0
5284.0
15.9
Equilibrium
7.6
7.3
0.0
0.39
Lime
768
Filtrate
6.6
5.0
vO
-------
and the denser sludge. Comparing the second run using air-jet milled
material with level 27, approximately 15 per cent less air-jet milled
limestone resulted in more neutralization as indicated by the aerator
overflow pH. The solids loading was about the same, but again a denser
sludge was obtained. The cost incurred in obtaining air-Jet milled
material and possibly the availability may, however, more than offset
the benefits of lower usage requirements due to increased efficiency.
The use of on-site wet grinding as provided in the tube mill described
by E. A. Mihok et al and used at the three previous sites appears to
offer a very promising alternative. The economics of this will be
discussed in the appendix on economics of the various treatment
processes.
The use of lime only in the neutralization step resulted in consid-
erable increases in costs for a number of reasons. The solids
produced, although lower in quantity than from the combined lime with
limestone process, have considerably poorer settling characteristics
offering problems in both clarification and thickening. The filtra-
tion rate of the sludge is also much lower than for an equally
concentrated sludge from the combined lime with limestone process.
The use of the ATLASEP 1A1 polyelectrolyte resulted in a denser sludge
that appeared to have about the same filterability as the other sludges
produced during the designed experiment. As discussed later, this may
be an extremely beneficial result.
The analysis of the data to select the best conditions for use in the
last two phases of the program was made before the statistical analysis
was done. The two levels with the lowest unit relative cost that were
felt to be capable of producing a satisfactory effluent were selected.
Most of the low unit relative cost levels were eliminated because
excessive solids carryover in the overflow had occurred at those
conditions. Levels 19 and 23 were selected as those levels that were
felt could best produce the desired results.
The results of the filtration tests are presented in Figures 24 to 27.
The 30 per cent submergence and one revolution per minute conditions
were selected for further tests because of the consideration that about
a 20 per cent reduction in cost of the filter unit as opposed to a 50
per cent submergence unit would result and the maintenance costs would
be significantly lower. Based on these tests using level 23 conditions,
a flow rate of 0.19 to 0.20 gallons per minute per square foot at a
knife advance of 0.001 inches per revolution was expected. A CELITE
501 precoat was used for all tests.
The round-the-clock operation was made at level 23 conditions. The
system was operated for approximately 33 hours during which time two
precoats were applied to the filter. The first precoat had a usable
thickness of about 0.6 inches. At an average knife advance of 0.0010
-97-
-------
FIGURE 24
FILTRATION CHARACTERISTICS
LEVEL 19 SLUDGE
0.3
z
i
DRUM SPEED
MIN'REV
1.00
0.2
o
I
0.1
i
oo
OX
I
CONDITIONS f*.
FILTER AID CELITE^SOl
SUBMERGENCE 50%
SLUDGE SOLIDS 0.8%
0.002 0.004
KNIFE ADVANCE -INCHES/ REV
0.006
-------
i
\D
VO
I
0.3
CN
o
I 0.2
0.1
FIGURE 25
FILTRATION CHARACTERISTICS
LEVEL 19 SLUDGE
DRUM SPEED
MIN/REV
1.00
FILTER AID CELITE>
SUBMERGENCE 30%
SLUDGE SOLIDS 1.0%
'501
0.002 0.004
KNIFE ADVANCE- INCHES/ REV
0.006
-------
FIGURE 26
FILTRATION CHARACTERISTICS
LEVEL 23 SLUDGE
0.3
DRUM SPEED
MIN/REV
1.00
z
i
CONDITIONS f-
FILTER AID CELITE^
SUBMERGENCE 50
SLUDGE SOLIDS 0.7
501
o
• 0.2
0.1
i
o
o
0.00 0.004
KNIFE ADVANCE- INCHES/REV
0.006
-------
FIGURE 27
FILTRATION CHARACTERISTICS
IEVEL 23 SLUDGE
0.3
i
t—•
o
i—•
i
<
o
0.2
0.1
DRUM SPEED
M IN/REV
1.00
1.56
CONDITIONS Q.
FILTER AID CELITE 501
SUBMERGENCE 30 %
SLUDGE SOLIDS 0.7%
0.002
KNIFE ADVANCE - INCHES/ REV
0.004
-------
inches per revolution, an average flow rate of 0.195 gallons per minute
per square foot was obtained. The second precoat had a usable thickness
of 1.1 inches. The filter was initially operated with an average knife
advance of 0.0011 inches per revolution and an average filtration rate
of 0.165 gallons per minute per square foot was obtained. During this
period, however, the cake appeared to be undergoing compression with
the filtration rate steadily increasing from 0.13 to 0.20 gallons per
minute per square foot. The knife advance was increased so that an
average advance of 0.0017 inches per revolution was obtained. The opti-
mum knife advance thus appears to be 0.001 inches per drum revolution.
The average filtration rate during this period was 0.205 gallons per
minute per square foot. No indication of precoat penetration and blinding
was observed during either run.
The analysis of composite samples from the round-the-clock run are pre-
sented in Table IXX. A material balance based on these figures is found
in Table XX. Difficulty was encountered with both feeding systems during
the round-the-clock run. Measurements indicated that the limestone feed
rate was 0.011 pounds per gallon rather than the 0.015 pounds per gallon
level desired. In addition, difficulty was encountered in maintaining
a pH between 8.5 and 9 in the thickener overflow that would insure
sufficient precipitation of the ferrous iron.
The relationship indicated by the statistical analysis between sludge
solids and filtration rate was used in making optimization calculations
for the process based on level 23 conditions. A plot of the filtration
rate versus the sludge solids concentration is presented in Figure 28.
A linear regression was made on the data to obtain an equation describing
the filtrate rate as a function of the sludge solids concentration. Using
this relationship and a material balance around the sedimentation uiiit,
the cost for a rotary vacuum precoat filter unit at various sludge solids
concentrations was calculated. The results are presented in Figure 29.
In addition, settling tests had been run for various concentrations of
the solids obtained during the round-the-clock operation that was analyzed
to give a log-log relationship between settling rate and solids concentra-
tion. Using the methods described by R. I. Dick^ and the above
relationship, the cost of a thickener to produce the various sludge solids
concentrations was calculated. The results are presented in Figure 30.
For concentrations above 6000 mg/1, the cost of the thickener was cal-
culated from values extrapolated beyond the range of the original data.
In costing the filter unit, the values above 12,000 mg/1 were based on
extrapolated flow rates. Combining the above two calculations, an
optimization curve for the combined sedimentation-sludge dewatering
process was obtained. This is presented in Figure 31.
A series of tests planned to confirm the extrapolated values in the
above calcualtions had to be canceled because of a drastic change in the
quality of the Proctor 2 water at the time they were scheduled. The
quality change may have been the result of dilution of the water in the
mine caused by heavy rains.
-102-
-------
o
OJ
i
TABLE IXX
24 Hour Run Composite Sample Analysis
Aerator Clarifier
Fluids
pH
Total Solids, mg/1
Free Mineral Acidity, mg/1 (as CaC03)
Total Acidity, mg/1 (as CaC03)
Sulfate, mg/1 (as 804)
Chloride, mg/1 (as Cl)
Iron, mg/1 (as Fe)
Calcium, mg/1 (as CaC03)
Magnesium, mg/1 (as CaC03)
Aluminum, mg/1 (as Al)
Silica, mg/1 (as Si02)
Filter Cake
Moisture, %
Carbonates (as % C02 - dry basis)
Silica (as % Si02 - dry basis)
Iron (as % Fe20-j - dry basis)
Calcium (as % CaC03 - dry basis)
Raw
2.6
3891
1668
1560
2230
2.7
470
432
334
171
75
Overflow
4.85
4327
668
460
2180
5.4
495
1493
346
158
72
0.001 in. /rain
79.7
4.6
18.1
32.8
14.8
Feed
8.30
5194
0
1
2150
5.6
480
2686
402
154
7
cut
Sludge
8.40
8677
0
0
2190
4.4
1270
3464
803
336
280
0.0017
Filtrate
7.20
3454
2
8
2150
2.4
1
2033
289
7
22
in./min cut
78.5
4.3
26.4
27.2
14.3
Clarifier
Overflow
7.65
3237
2
4
2530
2.7
10.5
1908
289
3
81
-------
TABLE XX
Material Balances
Flows: Raw - 10 gpra
Sludge Draw - 4 gpm
Overflow - 6 gpm
Quantities (Ib/hr)
Total Solids
Free Mineral Acidity
Total Acidity
Sulfate
Chloride
Iron
Calcium
Magnesium
Aluminum
Silica
Material Balance at Clarifier (Ib/hr)
Total Solids
Free Mineral Acidity
Total Acidity
Sulfate
Chloride
Iron
Calcium
Magnesium
Alum
Silica
Material Balance at Filter (Ib/hr)
Iron
Calcium
Raw
19.5
8.4
7.8
9.3
0.01
3.4
2.2
1.7
1.6
0.4
Feed
26
0
0.005
9.0
0.03
3.4
13.4
2.0
1.4
0.04
Aerator
Overflow
21.7
3.3
2.3
9.1
0.3
3.5
7.5
1.7
1.5
0.4
Overflow
9.72
0.006
0.012
5.1
0.006
0.05
6.0
0.84
0.018
0.24
Clarifier
Feed
26
0
0.005
9.0
0.03
3.4
13.4
2.0
1.4
0.004
Underflow
17.36
0
0
3.68
0.008
3.64
6.9
1.6
1.28
0.56
Sludge Filtrate
0
1
.96
.82
Trace
1.04
Sludge
17.36
0
0
3.68
0.008
3.64
6.9
1.6
1.28
0.56
Total Out
27.08
0.006
0.012
8.78
0.014
3.69
12.9
2.44
1.30
0.70
Clarifier
Overflow
9.72
0.006
0.012
5.1
0.006
0.048
6.0
0.84
0.018
0.24
Difference
+1.08
+0.006
+0.007
-0.22
-0.016
+0.29
-0.5
+0.44
-0.1
+0.66
Cake Difference
0.90 -0.
0.41 -0.
06
37
I
o
I-t
^
-------
FIGURE 28
EFFECT OF SLUDGE SOLIDS ON FILTRATION RATE
0.4
0.3
<
O
z
O
t 0.2
0.1
0.2 0.4 0.6 0.8 1.0
SLUDGE SOLIDS - %
1.2
-105-
-------
FIGURE 29
EFFECT OF SLUDGE SOLIDS
ON FILTER STATION COST
14
12
.- 10
i/>
o
z
o
l/t
at
8
UJ
oe
u.
!
LEVEL 23 SLUDGE
5 10 15
SLUDGE SOLIDS - GM/L
20
-106-
-------
FIGURE 30
THICKENER AREA REQUIREMENT
LEVEL 23 SLUDGE
100
o
<
UJ
of.
O
Ul
of.
O
UJ
ce.
80
60
40
20
I
468
UNDERFLOW SOLIDS -GM/L
10
-107-
-------
FIGURE 31
EFFECT OF SLUDGE SOLIDS
ON THICKENER & FILTER STATION COST
30
z
g
IS)
te.
20
D
Z
te.
ui
Z
ui
U
X
< 10
a.
<
u
468
SLUDGE SOLIDS - GM/L
TO
12
-.108-,
-------
Conclusions
Based on the results of the statistical test program, the sedimentation
and sludge dewatering steps were judged to have the greatest effect on
the costs of the treatment system. The greater the volume of the sludge,
the lower the sludge solids concentration, and the higher the filtration
rate. Optimization calculations were made that indicated that the
optimum sludge concentration was 1.1 per cent for operation of the
filter alone. Including the cost of the thickener unit required, the
optimum was reduced to 0.6 per cent solids. There is some degree of
uncertainty in these numbers because of the previous described extrapo-
lations. The use of a polyelectrolyte such as ATLASEP 1A1 to improve
the settling characteristics would appear to offer a method for further
optimizing the sedimentation-sludge dewatering process.
-109-
-------
APPENDIX E
ECONOMIC ANALYSIS
Purpose
The purpose of the economic analysis made on data from the different
sites was to provide a basis for comparing the various methods utilized
in neutralization of the mine water. Since some methods of neutrali-
zation were used at some sites and not at others, it would have been
desirable to have a common denominator to enable a rough estimation of
costs of a particular process at another site. Unfortunately, insuf-
ficient data was generated at the first site to even allow an estimate
of the costs for a treatment facility. At the last site, the main
objective focused more on optimization of the entire process, which
makes a comparison with the other sites meaningless since no optimi-
zation was attempted there. This therefore limits the number of
conclusions that can be drawn.
Basis
The cost estimates were based on the system given in Figure 5. The
cost estimates were made by the use of computer programs, copies of
which are available from the authors upon request. The estimating
procedure for the last site contained an optimization procedure similar
to that described in Appendix D. Costs were computed from values found
in the literature and updated to 1970 economics by use of the Marshall
and Stevens Equipment Cost Index. Amortization was computed as .per
the technique specified by the Office of Saline Water, Department of the
Interior.(5) A 20-year equipment life was assumed. The amortization
was thus calculated as 8.7 per cent of the total capital cost per annum.
Economics for Tests Run at Constant Flow Conditions
The Rushton Mining Company and Bennett Branch sites fit in this category.
It must be realized that the costs were computed based on the actual
operating conditions of the tests. Some degree of optimization might
therefore be possible that would further differentiate among the
methods used.
The estimated capital and operating costs for the methods used at the
Rushton Mining Company site are presented in Tables XXI and XXII re-
spectively. All limestone additions at this site were slurries formed
by wet attrition of limestone rock in a tube mill. The operating costs
indicate that the limestone with lime process is slightly more expensive
when compared with the other methods.
-Ill-
-------
TABLE XXI
Estimated Capital Costs for a 1.5 MGD Plant
Using Various Methods of Chemical Neutralization
Source: Rushton Mining Company, Osceola Mills, Pennsylvania
Note: All limestone feeds are as slurry produced in tube mill.
Neutralization
Item
Raw Feed Pump
Limestone Tube Mill
Limestone Reactor
Aeration Pond
Aeration Equipment
Chemical Storage Bin(s)
Chemical Feeder (s)
Chemical Reactor (s)
Thickener
Sludge Pump
Rotary Vacuum Precoat Filter
Sludge Disposal
Control Building
Instrumentation
TOTAL EQUIPMENT
Installation and Piping
Contingencies and Engineering
TOTAL CAPITAL COST
Limestone
$ 5,300
59,300
13,000
1,000
3,400
32,400
1,700
68,700
6,900
20,000
10,600
$222,300
$111,000
$ 33,300
$366,600
Limestone-
Lime
$ 5,300
44,800
13,000
1,000
3,400
1,900
5,800
13,000
32,400
1,700
95,500
9,500
20,000
12,400
$259,900
$129,500
$ 38,900
$428,300
Limes tone-
Magnesite
$ 5,300
43,700
13,000
1,000
3,400
300
3,000
13,000
32,400
1,700
58,300
5,800
20,000
10,100
$211,000
$105,500
$ 31.700
$348,200
Lirae-
Magnesite
$ 5,300
1,000
3,400
1,300
7,800
26,000
32,400
1,700
59,300
5,900
20,000
8.200
$172,300
$ 86,200
$ 25.900
$284,400
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TABLE XXII
Estimated Operating Costs for a 1.5 MGD Plant
Using Various Methods of Chemical Neutralization
Source: Rushton Mining Company, Osceola Mills, Pennsylvania
Note: All limestone
Amortization
Labor (366 man-hours @ $2.50)
Power (1.3 cents/kw-hr)
Chemicals
Limestone
Other Alkali (es)
Filter Aid
Subtotal
Maintenance
TOTAL ANNUAL OPERATING COST
Cost per thousand gallons treated
feeds are as
Limestone
$32,000
1,000
26,700
6,800
9,100
$75,600
$ 7,600
$83,200
$ 0.15
Cost per 100 pounds acidity treated $ 4.95
slurry produced
in tube mill.
Neutralization
Limestone- Limestone-
Lime Magnesite
$ 37,300
1,000
25,000
4,300
21,500
12,300
$101,400
$ 10,200
$111,600
$ 0.20
$ 6.65
$30,300
1,000
21,900
4,100
12,000
7,700
$77,000
$ 7,600
$84,600
$ 0.15
$ 5.04
Lime-
Magnesite
$24,800
1,000
10,800
31,000
7,900
$75,500
$ 7,500
$83,000
$ 0.15
$ 4.94
-------
The estimated capital and operating costs for the methods used at the
Bennett Branch site are presented In Table XXIII and XXIV respectively.
The operating costs here show more variability than the Rushton data.
The most interesting comparison is between the use of pulverized lime-
stone and a limstone slurry formed by attrition of limestone rock. As
discussed elsewhere in the report, the difference in particle size
distributions causes a significant difference in the neutralization
efficiencies of the two products. It is interesting to note that the
higher equipment and power costs to produce the finer limestone slurry
is more than offset by the cost differential for the raw materials which
is further amplified by the difference in efficiencies. The on-site
production of finer particles thus appears to be economical.
The only consistent trend exhibited by the data is that limestone alone
provides the least expensive treatment. Referring to Appendixes A through
C, it will, however, be noted that limestone alone presented difficulty
in obtaining satisfactory effluents under the conditions of the tests.
Differentiation between the various methods used on the basis of economics
is difficult because of the variability exhibited at the different sites.
Further work at optimizing the chemical dosages is required before a
meaningful economic comparison can be made.
Economics for Tests Run on Proctor 2. Hollywood, Pennsylvania
The optimization calculations made for this site were concerned with
finding the sludge solids concentration which minimized the combined
capital cost of the thickener and the filter. The estimated capital
costs at the optimum sludge concentration and the estimated operating
costs for various size plants ranging from 0.5 to 5.0 million gallons
per day are presented in Tables XXV and XXVI respectively. A graphical
presentation of the effect of plant size on operating cost per thousand
gallons is given in Figure 32. Based on the data, the operating costs
appear to stabilize for plant sizes above 2.5 million gallons per day.
The absence of the limestone dosage as a significant effect on the Unit
Relative Cost as reported in Appendix D was somewhat of a surprise. It
had been hoped that the test program would give some indication of the
optimum limestone dosage based on economics. From the results of the
tests, it was obvious that additional work covering a wider range of
limestone dosages would be required. Also, since the optimum sludge
concentration was most often out of the range of the original data on
settling rates, additional work is needed to confirm the relationships
developed for the higher concentration ranges.
Tables XXVII and XXVIII present estimated costs for a 1.5 million gallon
per day using lime neutralization. The plant was based on the sludge
settling tests run at the last site. Design was based on obtaining the
sludge solids concentration obtained during one run at that site, and
therefore represents an unoptimized figure. It is easy to see, however,
that this technique is considerably more expensive.
-114-
-------
TABLE XXIII
Estimated Capital Costs for a 1.5 MGD Plant
Using Various Methods of Chemical Neutralization
Source; Bennett Branch, Hollywood, Pennsylvania
Neutralization
Item
Raw Feed Pump
Limestone Tube Mill
Limestone Reactor
Aeration Pond
Aeration Equipment
Chemical Storage Bin(s)
Chemical Feeder (s)
Chemical Reactor (s)
Thickener
Sludge Pump
Rotary Precoat Filter
Sludge Disposal
Control Building
Instrumentation
TOTAL EQUIPMENT COST
Installation and Piping
Contingencies and Engineering
Limestone
Dust
$ 5,300
1,000
3,400
2,800
8,700
13,000
32,400
1,700
68,700
6,900
20,000
8,900
$172,800
$ 86,400
$ 25,900
Limestone
Slurry
$ 5,300
54,000
13,000
1,000
3,400
32,400
1,700
68,700
6,900
20,000
10,300
$216,700
$108,400
$ 32,500
Limestone
Slurry-
Lime
$ 5,300
54,000
13,000
1,000
3,400
1,000
4,600
13,000
32,400
1,700
62,500
6,200
20,000
10,900
$229,000
$114,600
$ 34,400
Limestone
Dust-
Magnesite
$ 5,300
1,000
3,400
6,900
16,700
26,000
32,400
1,700
68,700
6,900
20,000
9,500
$198,500
$ 99,300
$ 29,800
Limestone
Dust
Fully Calc.
Dolomite
$ 5,300
1,000
3,400
5,300
17,200
26,000
32,400
1,700
98,200
9,800
20,000
11,000
$231,300
$115,800
$ 34,700
Limestone
Slurry
Part. Calc.
Dolomite
$ 5,300
55,800
13,000
1,000
3,400
2,500
8,400
13,000
32,400
1,700
68,700
6,900
20,000
11.600
$243,700
$122,000
$ 36,600
TOTAL CAPITAL COST
$285,100 $357,600 $378,000 $327,600
$381,800
$402,300
-------
TABLE KXIV
Estimated Operating Costs for a 1.5 MGD Plant
Using Various Methods of Chemical Neutralization
Source: Bennett Branch, Hollywood, Pennsylvania
Neutralization
Amortization
Labor
(366 man-hours (? $2.50)
Power
(1.3 cents/kw-hr)
Chemicals
Limestone
Other Alkali
Filter Aid
Subtotal
Maintenance
TOTAL ANNUAL OPERATING COST
Cost per thousand gallons
Limestone
Dust
$ 24,800
1,000
11,600
47,800
9,100
$ 94,300
$ 9,400
$103,700
$0.19
Limestone
Slurry
$ 31,200
1,000
25,300
5,800
9.100
$ 72,400
$ 7,200
$ 79,600
$0.15
Limestone
Slurry-
Lime
$ 32,900
1,000
24,800
5,800
10,700
8,300
$ 83,500
$ 8,400
$ 91,900
$0.17
Limestone
Dust-
Magnesite
$ 28,500
1,000
11,650
75,900
123,500
9,100
$249,600
$ 25,000
$274,600
$0.50
Limestone
Dust-
Fully Calc.
Dolomite
$ 33,200
1,000
13,800
47,800
69,000
13,000
$177,800
$ 17,800
$195,600
$0.36
Limestone
Slurry-
Part. Calc.
Dolomite
$ 35,000
1,000
25,800
6,200
67,500
9.100
$144,600
$ 14.400
$159,000
$0.29
treated
Cost per 100 pounds acidity $6.74
treated
$5.17
$5.96
$17.84
$12.70
$10.31
-------
TABLE XXV
Estimated Capital Costs for Various Size Plants
Using Increased Efficiency Limestone-Lime Process
Source; Proctor No. 2, Hollywood, Pennsylvania
Plant Size - MGD
Item
Raw Feed Pump
Limestone Storage Bin
Limestone Feeder
Limestone Reactor
Aeration Pond
Helixors and Blowers
Lime Storage Bin
Lime Feeder
Lime Reactor
Thickener
Sludge Pump
Rotary Precoat Filter
Sludge Disposal
Control Building
Ins trumentation
TOTAL EQUIPMENT
Installation and Piping
Contingencies and Engineering
TOTAL CAPITAL COST
Calculated Optimum Sludge
0.5
$ 3,100
1,500
7,000
7,700
600
4,500
1,600
5,400
7,700
57,200
2,100
209,000
20,900
20,000
17,500
$365,800
$182,900
$ 54,900
$603,600
7,000
1.0
$ 4,400
2,800
8,800
10,700
1,300
6,100
3,100
6,800
10,700
95,300
2,900
418,000
41,800
20,000
31,600
$ 664,300
$ 332,200
$ 99,600
$1,096,100
7,000
1.5
$ 5,300
4,100
10,100
13,000
1,900
7,400
4,400
7,800
13,000
152,600
3,400
586,900
58,700
20,000
44,500
$ 933,100
$ 466,600
$ 140,000
$1,539,700
8,000
2.5
$ 6,900
6,500
11,900
16,600
3,200
11,000
7,000
9,300
16,600
187,100
4,100
934,700
93,500
20,000
66,400
$1,394,800
$ 697,400
$ 209.200
$2,301,400
9,000
5.0
$ 9,700
12,100
15,000
23,200
6,500
20,200
13,000
11,600
23,200
197,900
6,200
1,956,200
195,600
20,000
125,500
$2,635,900
$1,318,000
$ 395.400
$4,349,300
8,000
Concentration, mg/1
-------
TABLE XXVI
Estimated Operating Costs for Various Size Plants
Using Increased Efficiency Limestone-Lime Process
Source: Proctor No. 2, Hollywood, Pennsylvania
Plant Size - MGD
Amortization
Labor (366 man-hours @ $2.50)
Power (1.3 cents/kw-hr)
Chemicals
Limestone
Lime
Filter Aid
Subtotal
Maintenance (10% of above)
0.5
$ 52,500
1,000
18,900
21,900
17,900
27,700
$139,900
$ 14,000
1.0
$ 95,400
1,000
35,500
43,800
35,800
55,500
$267,000
$ 26,700
1.5
$133,900
1,000
50,000
65,700
53,600
77,900
$382,100
$ 38.200
2.5
$200,200
1,000
78,600
109,500
89,400
124,000
$602,700
$ 60,300
5.0
$ 378,400
1,000
153,900
219,000
178,900
259,600
$1,190,800
$ 119,100
TOTAL ANNUAL OPERATING COST $153,900 $293,700 $420,300 $663,000 $1,309,900
Cost per thousand gallons $0.84 $0.80 $0.77 $0.73 $0.72
treated
Cost per 100 pounds acidity $5.81 $5.54 $5.28 $5.00 $4.95
treated
i
CO
-------
0.90
FIGURE 32
EFFECT OF PLANT SIZE ON OPERATING COST
o
o
o
080
VD
I
O
U
O
z
of
LU
a.
O
0.70
0
PLANT SIZE -MOD
-------
TABLE XXVII
Estimated Capital Costs for a 1.5 MGD Treatment Plant
Using Lime Neutralization
Source; Proctor No. 2, Hollywood, Pennsylvania
Item
Raw Feed Pump
Lime Storage Bin
Lime Feeder
Lime Reactor
Aeration Pond
Helixors and Blowers
Thickener
Sludge Pump
Rotary Precoat Filter
Sludge Disposal
Control Building
Instrumentation
TOTAL EQUIPMENT COST
Installation and Piping
Contingencies and Engineering
TOTAL CAPITAL COST
$ 5,300
8,800
10,100
13,000
1,900
7,400
218,000
4,500
1,109,000
110,900
20,000
75.500
$1,585,000
$ 792,500
$ 237.800
$2,615,300
-120-
-------
TABLE XXVIII
Estimated Operating Costs for a 1.5 MGD Treatment Plant
Using Lime Neutralization
Source; Proctor No. 2, Hollywood, Pennsylvania
Amortization $228,000
Labor (366 man-hours @ $2.50) 1,000
Power (1.3 cents/kw-hr) 88,000
Chemicals
Lime 115,000
Filter Aid 147.OOP
Subtotal $579,000
Maintenance $ 58.000
TOTAL ANNUAL OPERATING COST $637,000
Cost per thousand gallons treated $ 1.16
Cost per 100 pounds acidity treated $ 8.02
-121-
-------
BIBLIOGRAPHIC: Johns-Manville Research &
Engineering Center.
Rotary Precoat Filtration of Sludge from
Acid Mine Drainage Neutralization, Final
Report WQO, EPA Grant No. 14010 DII,
December 1970.
ABSTRACT
Rotary vacuum precoat filtration was in-
vestigated as a means for dewatering sludge
produced by the neutralization of mine
drainage at four locations in Pennsylvania
during 1969 and 1970.
The process used at these sites consisted
of neutralization, aeration, sedimentation,
and filtration. The alkalies investigated
ACCESSION NO.
KEY WORDS:
Mine Drainage
Neutralization
Lime
Limestone
Sludge
Rotary Precoat
Filtration
Dewater
Economics
Pennsylvania
BIBLIOGRAPHIC: Johns-Manville Research &
Engineering Center.
Rotary Precoat Filtration of Sludge from
Acid Mine Drainage Neutralization, Final
Report WQO, EPA Grant No. 14010 DII,
December 1970.
ABSTRACT
Rotary vacuum precoat filtration was in-
vestigated as a means for dewatering sludge
produced by the neutralization of mine
drainage at four locations in Pennsylvania
during 1969 and 1970.
The process used at these sites consisted
of neutralization, aeration, sedimentation,
and filtration. The alkalies investigated
ACCESSION NO.
KEY WORDS:
Mine Drainage
Neutralization
Lime
Limestone
Sludge
Rotary Precoat
Filtration
Dewater
Economics
Pennsylvania
BIBLIOGRAPHIC: Johns-Manville Research &
Engineering Center.
Rotary Precoat Filtration of Sludge From
Acid Mine Drainage Neutralization, Final
Report WQO, EPA Grant No. 14010 DII,
December 1970.
ABSTRACT
Rotary vacuum precoat filtration was in-
vestigated as a means for dewatering sludge
produced by the neutralization of mine
drainage at four locations in Pennsylvania
during 1969 and 1970.
The process used at these sites consisted
of neutralization, aeration, sedimentation,
and filtration. The alkalies investigated
ACCESSION NO.
KEY WORDS:
Mine Drainage
Neutralization
Lime
Limestone
Sludge
Rotary Precoat
Filtration
Dewater
Economics
Pennsylvania
-------
were limestone, limestone with hydrated lime, calcined magne-
site, partially and fully calcined dolomite, and hydrated
lime. Filter aids tested included HYFLO SUPER-CEL, CELITE
501, CELITE 503, and CELITE 545. Work at the first three
locations indicated that limestone and hydrated lime were
the preferred alkalies and that CELITE 501 was the prefer-
red filter aid.
A more extensive program was conducted at the fourth site.
A 27 run factorial experiment was conducted investigating
the effect of flow rate, limestone feed level, aeration level,
and sludge recirculation on equipment operation and on process
cost. The significant variables affecting process cost were
found to be sludge solids content, the filtration rate, and
sludge recirculation. A detailed economic analysis of the
process is included in the report.
were limestone, limestone with hydrated lime, calcined magne-
site, partially and fully calcined dolomite, and hydrated
lime. Filter aids tested included HYFLO SUPER-CEL, CELITE
501, CELITE 503, and CELITE 545. Work at the first three
locations indicated that limestone and hydrated lime were
the preferred alkalies and that CELITE 501 was the prefer-
red filter aid.
A more extensive program was conducted at the fourth site.
A 27 run factorial experiment was conducted investigating
the effect of flow rate, limestone feed level, aeration level,
and sludge recirculation on equipment operation and on process
cost. The significant variables affecting process cost were
found to be sludge solids content, the filtration rate, and
sludge recirculation. A detailed economic analysis of the
process is included in the report.
were limestone, limestone with hydrated lime, calcined magne-
slte, partially and fully calcined dolomite, and hydrated
lime. Filter aids tested included HYFLO SUPER-CEL, CELITE
501, CELITE 503, and CELITE 545. Work at the first three
locations Indicated that limestone and hydrated lime were
the preferred alkalies and that CELITE 501 was the prefer-
red filter aid.
A more extnesive program was conducted at the fourth site.
A 27 run factorial experiment was conducted investigating
the effect of flow rate, limestone feed level, aeration level,
and sludge recirculation on equipment operation and on process
cost. The significant variables affecting process cost were
found to be sludge solids content, the filtration rate, and
sludge recirculation. A detailed economic analysis of the
process is included in the report.
-------
A cce.ssion Number
Subject Field & Croup
SELECTED WATER RESOURCES ABSTRACTS
INPUT TRANSACTION FORM
Organization
Johns-Manville Products Corporation, Research and Engineering Center,
Manville, New Jersey 08835
Title
Rotary Precoat Filtration of Sludge from Acid Mine Drainage Neutralization
10
Authorfs)
T. S. Brown
16
Project Designation
E.P.A. lUOlO DII
21 Note
22
Citation
Water Pollution Control Research Series No. 1^010 DII, 12/70, Office of
Research and Monitoring, Environmental Protection Agency, Washington, D. C.
Descriptors (Starred First)
Ine Drainage*, Acid Mine Drainage,* Neutralization,* Lime,* Limestone,* Sludge,*
Filtration,* Econpmics, Dewatering
25
Identifiers (Starred First)
Vacuum Filter,* Rotary Precoat Filtration,* Pennsylvania
27
Rotary vacuum precoat filtration was investigated as a means for dewatering sludge
produced by the neutralization of mine drainage at four locations in Pennsylvania
during 1969 and 1970.
The process used at these sites consisted of neutralization, aeration, sedimentation,
and filtration. The alkalies investigated were limestone, limestone with hydrated
lime, calcined magnesite, partially and fully calcined dolomite, and hydrated lime.
Filter aids tested included HYFLO SUPER-GEL, CELITE 501, CELITB 503, and CELITE 5^5.
Work at the first three locations indicated that limestone and hydrated lime were
the preferred alkalies and that CELITE 501 was the preferred filter aid.
A more extensive program was conducted at the fourth site. A 27 run factorial ex-
periment was conducted investigating the effect of flow rate, limestone feed level,
aeration level, and sludge recirculation on equipment operation and on process cost.
The significant variables affecting process cost were found to be sludge solids
content, the filtration rate, and sludge recirculation. A detailed economic analysis
of the process is included in the report.
Abstractor
R. D. Hill
Institution
Environmental Protection Agency
WR:102 (REV. JULY 1969)
WRSIC
SEND TO: WATER RESOURCES SCIENTIFIC INFORMATION CENTER
U.S. DEPARTMENT OF THE INTERIOR
WASHINGTON. D. C. 20240
* GPO: 1969-359-339
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