WATER POLLUTION CONTROL RESEARCH SERIES
ORD 17O ', Of- K AOb/ 7O
"DEVELOPMENT OF A PILOT PLAKT TO
DEMONSTRATE REMOVAL OF CARBONACEOUS,
NITROGENOUS AND PHOSPHORUS MATERIALS FROM
ANAEROBIC DIGESTER SUPERNATANT AND RELATED
PROCESS STREAMS"
U.S. DEPARTMENT OF THE INTERIOR • FEDERAL WATER QUALITY ADMINISTRATION
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WATER POLLUTION CONTROL RESEARCH SERIES
The Water Pollution Control Research Reports described the results and
progress in the control and abatement of pollution of our Nation’s
waters. They provide a central source of information on the research,
development, and demonstration activities of the Federal Water Quality
Administration, Department of the Interior, through in-house research
and grants and contracts with Federal, State, and local agencies, research
institutions, and industrial organizations.
Water Pollution Control Research Reports will be distributed to requesters
as supplies permit. Requests should be sent to the Planning and Resources
Office, Office of Research and Development, Federal Water Quality Adminis-
tration, Department of the Interior, Washington, 0. C. 20242.
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DEVELOPMENT OF A PILOT PLANT TO DEMONSTRATE REMOVAL OF
CARBONACEOUS. NITROGENOUS, AND PHOSPHORUS MATERIALS FROM
ANAEROBIC DIGESTER SUPERNATANT AND RELATED PROCESS STREAMS
by
George E. Bennett
Environmental Engineering Department
Centra] Engineering Laboratories
FMC Corporation
Santa Clara, California 95052
for the
FEDERAL WATER QUALITY ADMINISTRATION
DEPARTMENT OF THE INTERIOR
Program #17010 FKA
Contract #14-12-414
FWQA Project Officer, E. F. Barth
Advanced Waste Treatment Research Laboratory
Cincinnati, Ohio
May, 1970
For sale by the Superintendent of Documents, tT.8. Government Printing Office
Washington, D.C. 20402 - Price *1
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FWQA Review Notice
This report has been reviewed by the Federal Water
Quality Administration and approved for publication.
Approval does not signify that the contents neces-
sarily reflect the views and policies of the Federal
Water Quality Administration, nor does mention of
trade names or comercial products constitute en-
dorsement or recommendation for use.
1
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ABSTRACT
Digester supernatarit contains high concentrations of nitrogen and phosphorus.
Also, poor quality supernatant discharged from an anaerobic digester can have
an adverse effect on the overall efficiency of a wastewater treatment plant.
Under F QA sponsorsnip, the Central Engineering Laboratories of the FMC Corp-
oration undertook to build and demonstrate the operation of a unique, trailer-
mounted, and completely self-contained pilot plant. The pilot plant is designed
to investigate the improvement of digester supernatant quality, with particular
emphasis on the removal of nitrogen and phosphorus. The pilot plant treatment
sequence consists of carbon dioxide removal via air-stripping, lime precipita-
tion of phosphorus and carbonaceous particulate matter, and removal of nitrogen
by packed-tower ammonia-stripping.
The pilot plant was operated over a two-month period at a trickling filter
plant where two-stage anaerobic digestion is practiced. The pilot plant oper-
ated in a reliable and consistent fashion with respect to both tkle mechanical
performance and the process data obtained. A wide range of operating condit-
ions was investigated in a convenient and effective manner.
It was found that 80—95% of supernatant phosphorus could be removed at a lime
dosage equal to 50 pounds of hydrated lime per pound of phosphorus removed.
Average ammonia-nitrogen removal was 82%, achieved at an air flow rate equal
to 83,000 cubic feet of air per pound of 1H 3 -N removed.
Normal lime precipitation removed about one-half of tne supernatant TOG, COD,
and Organic Nitrogen. The average decrease in suspended solids was 64%.
This report is submitted in fulfillment of Contract No. 14-12-414 (Program
No. 17010 FKA) between the Federal Water Quality Administration and the
Central Engineering Laboratories of FMC Corporation.
Key Words: Sludge Treatment, Supernatant Nutrient Removal, Phosphorus
Removal, Nitrogen Removal, Ammonia Stripping.
111
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SECTION
C 0 N T E N T S
P AGE
CONCLUSIONS
INTRODUCTION .
BACKGROUND ANU OBJECTIVES . . . .
DESIGN AND CONSTRUCTION OF PILOT PLANT
OPERATION OF PILOT PLANT . . . .
FIELUTESTSITE . . .. .
RESULTS OF FIELD TESTING . . . .
DISCUSSION . . . . . . . . . . . . .
ECONOMIC CONSIDERATIONS . . . . .
ACKNOWLEDG 1ENTS . . . . . . . .
REFERENCES . . . . . . . . . . . . .
APPENDIX
• . I I S • • S S • S
• S S I S S I S S S S
• I I • I I S S S I S
• I • I •
I • S I S S S S I S S
• S S I S S S I S S •
• I S • S I I S • • S
S S S I S S S S S S S
• I S S S S S • S S S
• I S S I S S S S S S
I.
II .
III.
‘VS
V.
VI.
VII .
VIII.
Ix.
XI
XI.
XIII
1
3
5
7
11
15
19
47
57
59
61
63
V
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LIST OF FIGURES
TITLE
8
8
9
9
FIGURE NO .
PAGE
Figure
1
Supernatant Beneficiation Pilot Plant
TreatmentSequence. . . . . . . . . . . . •..
6
Fiqure2
ReactorVessel . . ... . •øê*S••S• . .
Figure
3
Reactor Vessel Air—Diffusion lanifold . . . . . .
Figure
4
Rear View of Ammonia—Stripping Columns . . . . . . .
Figure
5
Two—Inch Intalox Saddles in No. 1 Stripping Column.
Figure
6
Digester Supernatant Beneficiation Pilot Plant
Readyforlransport •0••S• .......
.12
Figure
7
Ammonia-Stripping Column Flow Pattern . . . . . . . . .
14
Figure
8
Titration Curves for Irvington WTP Digester
S upernatant . . . . . . . . . . . * . . . . . . .
17
Figure
9
Carbon Dioxide Stripping at Varying Air Rates . . . . .
22
Figure
10
Reaction Tank During Normal Carbon Dioxide
Stripping (Air @ 550 cfm) . . . . . . . . . . . .
23
Figure
11
Reaction Tank During a High Air Flow Carbon
Dioxide Stripping (Air @ 700 cfm) . . . . . . . .
23
Figure
12
Waste Sludge Disposal Area . . . . . . . . . . . . . .
36
Figure
13
Ammonia-Nitrogen Removal vs A/W Ratio . . . . . . . . .
44
Figure
14
Recomended Facilities for Beneficiation of
Irvington WTP Digester Supernatant . . . . . . . .
52
Figure
15
Supernatant Benefi ci ati on Facilities
For 50 MGD Plant* . . . . . . . . . . . . . . . . .
54
vii
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TABLE NUMBER
LIST OF TABLES
TITLE
PAGE
Table I
Table II
Table III
Table IV
Table V
Table VI
Table VII
Table VIII
Table IX
Table X
Table XI
Table XII
Table XIII
Table XIV
Table XV
Table XVI
• • • • • • 18
• • • . • 20
• 25
• 26
• 28
• 29
• 30
• 32
• • • • • 33
• . • 35
• • • 37
• • . • 39
• 41
• 45
• 46
I • • I • • 16
Laboratory Characterization of Digester
Supernatant, Irvington, W.T.P. • • .
Characteristic of Irvington WTP Supernatant
Composition of Digester Supernatant Liquors
Effect of Carbon Dioxide Stripping Time
On Lime Dosage • • • ••. • • • • • • • • • •
Summary of Operating Temperatures • • • • • • • •
Removal of Total Phosphorus • • • • • • • • • • •
Removal of Total Orthophosphate . • • • • • • •
Removal of Soluble Orthophosphate • • • • • • • •
Removal of Suspended Solids • • • • • • • • • • •
Effectiveness of Lime Treatment and Settling
Sludge Production • • • • • • • • • • • • •
Effect of Supernatant Strength on Lime
Precipitation Performance* • • • • • • • •
Effect of Reactor Vessel Settling Period • •
Ammonia Nitrogen Removal Summary . • • . . • • . .
Ammonia-Stripping Requirements • • • • • • • • • •
Ammonia Stripping Temperature Summary . • • • • • •
ix
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SECTION I
CONCLUSIONS
1. Pilot plant operation at the Irvington WTP demonstrated that the trailer-
mounted unit can be conveniently and effectively used to investigate
supernatant beneficiation. It was possible to use tne pilot plant exactly
as intended without interfering with the normal operation of the Irvington
WTP. A wide range of operating conditions and situations were investigated
without difficulty. The pilot plant operated in a reliable and consistent
manner with respect to both mechanical performance and the process data
obtained.
2. Overall total phosphorus removal of at least 80% can be achieved at pH
values of 10.8 or greater. As the pH is increased above 10.8, the degree
of phosphorus removal also increases. At pH 11.4, 86% of tne total
phosphorus and 95% of the orthophosphate will be removed.
3. Supernatant beneficiation is a very economical means of phosphorus removal,
on the basis of cost per pound of phosphorus removed. The portion of
phosphorus which becomes concentrated in digester supernatant can be re-
moved at operating and capital equipment costs which are 8-9% and 93%
lower, respectively, than the operating and capital equipment costs for
removal of phosphorus occurring in normal wastewater concentrations.
1
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4. Amonia-nitrogen removal of 80-95% can be achieved at pH values in the
11.2 — 11.4 range. The stripping air requirement for 85% ammonia removal
at pFI 11.4 is 83,000 cubic feet per pound of amonia-nitrogen removed.
5. On the basis of cost per pound of nitrogen removed, amonia—stripping be-
comes more economical as the concentration of ammonia increases. Thus the
nitrogen which becomes concentrated in the digester supernatant (as
amonia) can be removed at a relatively low cost.
6. Although the supernatant beneficiation process is oriented mainly toward
nutrient removal, it also produces a major incidental improvement in over-
all supernatant quality. Operation at Irvington resulted in removal of
64% of the initial suspended solids, and roughly one-half of the initial
TOC, COD, and organic nitrogen.
7. No scaling of tank or stripping column surfaces was encountered during
the Irvington testing, wnich involved the total use of more than 2300
pounds of lime in processing over 50,000 gallons of supernatant.
8. The digester supernatant produced at the Irvington WTP, a trickling filter
plant, has considerably higher concentrations of ammonia nitrogen, phos-
phorus, suspended solids, and total organic carbon than supernatant pro-
duced at activated sludge plants. The stronger supernatant was readily
treatable, however, and the trailer-mounted pilot plant performed well
and met all effluent criteria.
2
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SECTION II
INTRODUCTION
Rapid eutrophication of lakes and waterways is a major environmental problem
facing our nation today. Nitrogen and phosphorus are key factors in the
eutrophication process. Conventional wastewater treatment is oriented toward
the stabilization of organic carbonaceous matter and is relatively ineffective
in removing nitrogen and phosphorus from wastewater. The problem of controlling
and minimizing the concentration of nutrients in wastewater treatment plant
effluents is, therefore, receiving much current attention.
Most of the nutrient removal schemes currently proposed or under investigation
involve the processing of the entire volume of treatment plant throuqh-put.
This is necessary in order to achieve a high level of overall nutrient removal.
it is conceivable, however, that situations presently exist or may arise where
only partial removal of nitrogen and phosphorus is required, or can be toler-
ated. Under these conditions, significant economies are available if nutrients
are removed at a point in the treatment process where they occur in relatively
high concentrations.
Anaerobic digester supernatants (and similar process streams such as centrate
liquors, vacuum filter filtrate, etc.) contain particularly high concentration
of nitrogen and phosphorus. Supernatant also contains a considerable amount
of carbonaceous organic material, sufficient in many cases to upset or reduce
the efficiency of aerobic treatment processes. Supernatant from anaerobic
digesters can therefore reduce or limit treatment plant performance. An economical
3
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process which could remove nitrogen, phosphorus, and carbonaceous material
from digester supernatant could be an effective means of improving the
operational efficiency of wastewater treatment plants, and at the same time
reduce the eutrophication potential of the treated effluents.
4
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SECTION III
BACKGROUND AND OBJECTIVES
The objectives of this project were: (1) to develop a process for improving
the quality of digester supernatant, (2) to produce a portable pilot plant
suitable for demonstrating and investigating digester supernatant beneficiation,
and (3) to demonstrate the satisfactory operation of the pilot plant under
realistic field conditions. These objectives were successfully met.
The project was done in three phases. Phase One work involved laboratory in-
vestigations to select and verify a feasible and reliable supernatant treatment
process. Phase Two consisted of the design and construction of a trailer-
mounted, self—contained pilot plant. Phase Three consisted of field operation
at a municipal wastewater treatment plant to demonstrate the applicability of
both the treatment process and the pibt plant to the investigation of digester
supernatant beneficiation.
The Phase One work has been described in detail in a previous report (1).
Briefly, it involved the laboratory—scale application of various unit processes
to the treatment of digester supernatants from two municipal wastewater treat—
ment plants. It was concluded that chemical precipitation (using lime) followed
by packed-tower air—stripping would constitute a practical and economical means
of removing nutrient materials and reducing the amount of organic carbonaceous
matter in anaerobic digester supernatants.
This report describes and summarizes the Phase Two and Phase Three work.
5
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FIGURE I
SUPERNATANT BENEFICIATION PILOT PLANT TREATMENT SEQUENCE
RETURN
TO MAIN
WTP THROUGH-PUT
STREAM
DIGE STER
SUPER NATANT
SLURRY OF
SLAI LIME
NI4 3 -N RELEASED
TO ATMOSPHERE
TO WASTE
OR
RE CA LC I NI NC
AND REUSE
NUTRIENT-FREE
SUPERNATANT
LIME COMPRESSED
SLUDGE AIR
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SECTION IV
DESIGN AND CONSTRUCTION OF PILOT PLANT
Following successful completion of the Phase One work, a trailer—mounted pilot
plant was designed and built.
Figure 1 indicates schematically the pilot plant treatment sequence. Pilot
plant operation is a combination of batch and continuous-flow treatment. Car-
box dioxide stripping and chemical precipitation are done on a batch basis,
while ammonia—stripping is accomplished on a flow—through basis. The key equip-
ment components are the Reactor Vessel and the Stripping Columns.
Reactor Vessel : The treatment sequence is set up so that a single 2000-gallon
tank, called the Reactor Vessel (Figure 2), can be used for stripping carbon
dioxide and also for flash-mixing, flocculation, and settling. An air-diffusion
manifold utilizing 33 Chicago Pump Company Uiscfusers is used for stripping the
carbon dioxide from fresh digester supernatant, as indicated by Figure 3. A
lift mechanism is provided so that the manifold can be raised above the oper-
ating liquid level (i.e., out of the water) as needed. The Reactor Vessel has
a conically-shaped lower portion to facilitate the efficient removal of settled
lime sludge. Sampling ports are located at various tank levels; samples may
also be drawn from the bottom of the settling cone.
7
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FIGURE 2
REACTOR VESSEL
FIGURE 3
REACTOR VESSEL
Al R DI FFUSIO1 MAUI FOLD
C’ I if JJ ’
8
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FIGURE 4
REAR VIEW OF
AMMON IA—STRIPPING COLUt1IIS
FIGURE 5
TWO-INCH INTALOX SADDLES
IN HO. 1 STRIPPING COLUMN.
NOTE REACTOR VESSEL EFFLUENT
DISTRIBUTOR PIPE.
I
A.
r 1
9
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Counter—Flow Stripping Columns : Ammonia—strippinq is clone in two 3,5 foot
diameter stripping columns (Fiqure 4). The columns can be o!,erated in series
or can be used separately. Each stripping colunn is 12 feet hinh overall and
contains 80 cubic feet of 2-inch plastic “Intalox ” saddles (Figure ).
The aninonia—stripping facilities are designed to permit a maximum degree of
operational versatility. Air—to—water (A/w) ratios of from 130 to 900 cubic
feet per gallon can be provided. A steam generator has been provided so that
the stripping—air temperature can be raised by steam injection, Appropriate
sampling ports are provided so that composite samples of Column #1 influent,
Column #1 effluent (which is also Column #2 influent), and Column #2 effluent
can be conveniently collected.
Trailer : All of the pilot plant components, including a small control buildinq
and an auxiliary 1250-gallon settling tank, are located on a sinnle axle flat-
bed trailer (Figure 6). All necessary auxiliary equipment (pumps, pipinq,
electrical switchgear, etc.) required for pilot plant operation is included as
an integral part of the trailer. A functional piping diagram indicating the
relative positions of the various components is also included in the Appendix.
A complete list of the various equipment components is included in the Appendix.
10
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SECTION V
OPERATION OF PILOT PLANT
The pilot plant is designed to process 2,000 gallons of supernatant at a time.
The normal treatnent sequence beqins by drawing or pumping 2,000 gallons of
the test supernatant into trie Reactor Vessel.
After the Reactor Vessel is filled, the air is turned on briefly (1-3 minutes)
to thoroughly mix tue test supernatant. A sample of the test supernatant is
then drawn from a sampling port located at mid-depth in the tank. After a re-
presentative sample of test supernatant is obtained, aeration is resumed.
Aeration of the supernatant causes carbon dioxide to be stripped from the
supernatant. Aeration in the Reactor Vessel is continued until the bulk of tue
carbon dioxide is removed and an equilibrurn pH has been reached.
After the excess carbon dioxide has been stripped out, phosphorus is removed by
chemical precipitation. This is accomplished by adding slaked lime (in slurry
form), flocculating for about 15 minutes through use of the Reactor Vessel
aeration system, and allowing the precipitated solids to settle in the quiescent
Reactor Vessel. Good removal oF phosphorus can be achieved at pH 10.0 or even
lower. However, higher pH values are required for the subsequent ammonia-
stripping operation, described below. Therefore, an excess of lime is used in
the phosphorus precipitation portion of the pilot plant process.
11
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FIGURE 6
DIGESTER SUPERNATANT BENEFICIATION PILOT PLANT READY FOR TRANSPORT
-a
-------
After the precipitated solids have settled, the sludge is drawn off. The
sludge can be held for an additional 1—2 hour period in the pilot plant auxiliary
settling/thickening tank. This practice is convenient to the general operating
routine and also permits the pilot plant operator to observe the degree of
“secondary” compaction and the decrease in sludge volume associated with the
additional settling time.
After the supernatant phosphorus has been precipitated, ammonia-nitrogen is
removed by countercurrent flow air-stripping in the packed columns. Liquid
flow rates of 5-15 gpm are used, with air flow at 2000 - 4500 cfm. The two
identical stripping towers are noramlly operated in series, as indicated by
Figure 7. The Reactor Vessel liquid flows downward through each of the two
stripping towers in series. At the same time, air is simultaneously blown
upwards through each column, in the opposite direction.
Ammonia—stripping is the final step in the pilot plant treatment sequence.
The Column #2 effluent is, therefore, also the pilot plant final effluent.
13
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FIGURE 7
AMMONJA-STRJPP NG COLUMN FLOW PATTERN
TOWER NO. 2
TOWER NO. 1
PHOSPHORUS
A ND
AMMONIA
FREE
EFFLUENT
PHOSPHORUS-FREE
REACTOR VESSEL EFFLUENT
14
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SECTION VI
FIELD TEST SITE
Field testing and operation of the trailer-mounted pilot plant took place at
the Irvington Wastewater Treatment Plant near Fremont, California. This plant
is part of the Union Sanitary District pollution control system and serves a
portion of the City of Fremont.
The Irvington WTP is a bio-filter plant designed for 10.5 1GD flow. During
the pilot plant test period, it was receiving about 50% of the design flow.
The anaerobic digestion facilities are well operated. There have been no
significant digester problems at this plant. Sludge is pumped to the digester
at 30—minute intervals, with the pumping period controlled by density meters.
lormally, 15,000—20,000 gallons of sludge are pumped to the two—stage digester
system per day. Supernatant is displaced from the secondary digester and is
returned to the plant headworks. The digester gas contains 34—36% carbon
dioxide, pH is in the 7.0 — 7.3 range, gas production is good, and volatile
acids are consistently below 150 mg/liter.
Treatment of the Irvington supernatant by the pilot plant process was simulated
on a bench—top scale at the FMC Laboratories. The results are summarized in
Table I and Figure 8. It was observed that nitrogen and phosphorus were
present in relatively high concentrations and that the particulate solids con-
tent of the supernatant was considerably higher than had been encountered
with the two supernatant used during the Phase One work. It was apparent that
operation at the Irvington plant would provide a challenging situation for
demonstrating the applicability of the pilot plant process.
15
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TABLE I
LABORATORY CHMACTERIZATION OF
DIGESTER SUPERt4ATANT
IRVINGTOU, W.T.P.
Untreated Supernatant Supernatant Decant
Sample* After Lime Treatment
7.1 10.7
Total Solids 4985 2753
Total Volatile Solids 3330 1821
Suspended Solids 2905 1190
Volatile Suspended Solids 2530 3U
COD 5407 2919
Total Carbon 3075 1214
Total Organic Carbon 1624 914
Ortho - P0 4 (as P) 91 5.9
Total Phosphate (as P) 141 37
NH3—Nitrogen (as N) 818 726***
Organic Nitrogen (as N) 282 176
Calcium 156 **
Magnesium 48 **
* All values except pH are in mg/liter
** Not Determined
Supernatant not air stripped after lime treatment
16
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FIGURE 8
TITRATION CURVES FOR IRVINGTON WTP DIGESTER SUPERNATANT
AFTER CO 2 REMOVAL
t3Y AIR STRIPPING
p
-J
CD
(J)
L .J
LL
=
12.0
11.0
10.
9.0
8.0
7.0
/
- - - -0 -
--0
BEFORE
CO 2 RE 1OVAL
0 .5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5
LIME DOSAGE ( GRAMS CaO PER LITER)
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TABLE II
CHARACTERISTICS OF IRVINGTON WTP SUPERNATANT
MAXIMUM VALUE MINIMUM VALUES
OR CONCENTRATION OR CONCENTRATION
(mg/liter) (mg/liter)
ANALYSIS
NUMBER OF
SAMPLES ANALYZED
AVERAGE VALUE
OR CONCENTRATION
(mg/i i ter)
-
TEMPERATURE
18
88°F
82°F
85°F
pH
18
7.42
7.10
7.26
SUSPENDED SOLIDS
18
3,200
1,640
2,205
(.
1,66
4,545
2,930
VOLATILE SUS—
PENDED SOLIDS
18
2,380
1,120
TOTAL SOLIDS
18
5,300
4,355
5 V0 Thhi
18
3,500
2,700
TOTAL CARBON
18
3,030
2,420
2,719
TOTAL ORGANIC
CARBON
18
1 25
,6
828
1,242
TOTAL —P0 4 (as P)
18
154
135
143
66
ORTHO-P0 4 (as P)
18
73
62
AMMONIA—NITROGEN
18
925
794
— 853
ORGANIC NITROGEN
9
381
260
.
ALKALINITY
18
3,962
3,637
3,780
87
VOLATILE ACIDS
18
132
46
CO.D.
HARDNESS
9
4,848
4,309
4,565 -
9
302
239
264
CALCIUM
MAGNESIUM
9
9
131
47
100
41
I 116
1 44
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SECTION VII
RESULTS OF FIELD TESTING
A total of twenty-three complete or partial operating runs were made at the
field test site (Irvin ton WTP). lechanical operation and performance of the
pilot plant met all design expectations. The treatment process liketiise oper-
ated as anticipated. In several respects, pilot plant results were better
than the laboratory results achieved during t ie Phase One work.
I RVINGTOI1 SUPERNATANT
The Irvington supernatant produced during the testing period was consistent in
quality, as indicated by Table Ii. In general, it was considerably stronger
than the supernatants studied during the Phase One work, which had been quite
similar to the supernatant values reported by 1asse1li (2). Table III sum-
marizes the Masselli data and the Phase One supernatants. The Irvington
supernatant contained roughly twice as much phosphorus and ammonia as either
the Phase One supernatants or the Masselli supernatants.
As noted previously, all control and operating parameters indicate that the
anaerobic digestion system at the Irvington plant operates normally and
efficiently. It is believed that the higher—than—usual concentrations of nutrients
in the Irvington supernatant reflect efficient digester loading. This may be a
normal condition at bio—filter plants (the Phase One plants were both activated
sludge plants) or it may be a result of the up-to-date sludge handling techniques
and equipment used at the Irvington plant.
19
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TABLE III
COMPOSITION OF DIGESTER SUPERNATANT LIQUORS
ANALYSIS
PHASE ONE SUPERNATANTS
SUPERNATANT VALU
MILPITAS
TREATMENT
PLANT*
SAN JOSE
TREATMENT
PLANT
LAGOON *
REPORTED BY
MASSELLI (2)
pH
7.04
7.8
7.3
SUSPENDED SOLIDS
383
143
---
VOLATILE SUSPENDED SOLIDS
299
118
——-
TOTAL SOLIDS
1,475
2,160
3,260
TOTAL VOLATILE SOLIDS
814
983
1,541
TOTAL CARBON
740
930
---
TOTAL ORGANIC CARBON
443
320
---
TOTAL PHOSPHATE (as P)
63
87
56
SOLUTION PHASE ORTHO-P0 4 (as P)
45
74
---
NH 3 NITROGEN (as N)
253
559
402
ORGANIC NITROGEN (as N)
53
91
———
ALKALINITY (as CaCO 3 )
1,349
1,434
1,675
HARDNESS (as CaCO 3 )
322
250
890
COD
1,384
1,310
---
*A11 values except pH are in mg/liter.
20
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BATCH AIR—STRIPPING OF CARBON DIOXIDE
Field results confirmed the preliminary laboratory indications that initial air-
stripping of carbon dioxide is an important step in the supernatant beneficia-
tion process. Reasonably complete removal of carbon dioxide produced a one-
unit increase in supernatant ph (from 7.2 to pH 8.2). The lime requirement was
increased by as much as 25% when carbon dioxide was only partially stripped out
prior to chemical treatment (Figure 8). Satisfactory removal of carbon dioxide
was achieved by batch stripping for 60 minutes at an air flow of 550 cfm. At
this A/W* ratio (16.5 cubic feet per gallon), the highest practicable pH (8.1
to 8.2) was consistently achieved. Figure 9 indicates the effect of batch air-
stripping on the pH of the supernatant. It was possible to raise the ph more
rapidly if a higher air flow rate (800 cfm) was used. The pH could be raised
to 8.2 within 30 minutes by using a higher air flow rate, 800 cfm. However,
this resulted in rapid and excessive foaming, as Figure 11 indicates. Figures
10 and 11 illustrate the degree of foaming associated with the normal air flow
rate as opposed to the higher flow rate.
The A/W ratio when operating at 550 cfm was 16.5 cubic feet per gallon. This
was considerably in excess of the 3 cubic feet per gallon A/W ratio anticipated
on the basis of the Phase One work. This discrepancy is probably due to the
fact that it is difficult to accurately simulate carbon dixoide stripping on a
small—scale laboratory basis. In any event, the air requirement for carbon
* Air—to—Water, cubic feet per gallon.
21
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FIGURE 9
CARBON DIOXIDE STRIPPING AT VARYING AIR RATES
HIGH AIR
800 cfr
L..._._ NORMAL (WERATTNG
RANGE
550 cfr OF AIR
400 cfm
60
C02 STRIPPING TIME (MINuTEs)
0
‘V 0
=
C-
8.4
8,2
8.0
7.8
7.6
7.4
7.2
7.0
LOW AIR
10 20 30 40 50
22
-------
.. __ 0-
FIGURE 10
REACTION TANK DURING
NORMAL CARBON DIOXIDE
STRIPPING (AIR @ 550 CFM)
FIGURE 11
REACTION TANK DURING
A HIGH AIR FLOW CARBOU DIOXIDE
STRIPPING (AIR @ 700 CFM)
23
-------
dioxide stripping was well within the capabilities of the pilot plant blower
C 550 cfm required versus 4500 cfm blower capacity).
Table IV indicates the process lime requirements at the Irvlngton plant in
relation to carbon dioxide stripping. At an air flow rate of 550 cfm, reducin
the air stripping timeby 67-75% increased the required lime dosage by 25%.
Operating temperatures during field testing are sunriarized in Table V. Ambien
air temperatures were in the 50-80°F range. The average air temperature was
62°F, and there was very little temperature decrease during the normal one—hou
carbon dioxide stripping interval.
No significant change in alkalinity occurred during carbon dioxide stripping.
TOC data relative to the batch stripping operation were erratic, but no signi-
ficant loss of volatile material was indicated. On the average, there was a
5% decrease in total carbon during batch stripping. As expected, there was no
reduction of the NH3-N concentration as carbon dioxide was removed.
Carbon dioxide stripping could be done more efficiently if foaming could be
controlled by water spray or an anti—foamant additive. The decrease in
stripping time would more than offset the increase in the air flow rate, pro-
ducing a lower resultant A/W ratio. This could be a significant factor in a
flow—through (rather than batch) system, since the required stripping vessel
volume could be reduced by 50%.
24
-------
TABLE IV
EFFECT OF CARBON DIOXIDE STRIPPING TIME
ON LIME DOSAGE
Irifluent
SuDernatant
pH
Carbon Dioxide
Stripping Time
(Minutes)
Carbon Dioxide
Stripped
Supernatant
pH
Lime Dose
(mg/liter)
pH After
Lime
Addition
A/W Ratio
(Cubic feet!
gallon)
7.1
7.3
7.2
7.2
7.2
7.2
7.3
7.3
60
45
30
30
15
15
15
8.1
8.2
8.1
8.U
8.0
7.9
7.9
7.7
6000
6000
6000
6600
6000
4500
7500
11.4
11.2
10.8
11.1
10.1
11.3
16.5
12.4
8.3
8.3
4.1
4.1
-------
TABLE V
SUMMARY OF OPERATING TEMPERATURES
Maximum Minimum Average
Sample Temperature* Temperature* Temperature*
Influent Supernatant 88 82 85
Supernatant After CO 2 Stripping 88 73 83
Reactor Vessel Effluent 86 76 82
Column #1 Effluent 79 61 68
Column #2 Effluent 77 59 66
(Process Effluent)
Ambient Air Temperature 80 51 62
Compressed Air Temperature 96 73 34
Stripping Tower Air Temperature 76 53 65
* All temperatures in 0 F.
26
-------
LIME PRECIPITATION TREATMENT
The pilot plant chemical precipitation step has two main oojectives. The first
is to remove as much phosphorus as possible; the second is to produce a Reactor
Vessel effluent with a high pH value, whicii is required for subsequent ammonia—
stripping. Lime is the most suitable coagulant chemical. It is effective in
precipitating phosphorus,and also raises the 2H. Under normal operating con-
ditions (i.e., with carbon dioxide strioped out prior to lime treatment),
6,000 mg/liter of slaked lime produced a Reactor Vessel pH in the 10.8 - 11.4
range.
Lime precipitation produced total phosphorus removals of 80% or more at pH
values of 10.8 or greater. The average total phosphorus removal under normal*
operating conditions was 84%. The deqree of total pnospnorus removal gradually
increased as the pH was increased above the 10,8 pH value. The maximum Total P
removal under normal operating conditions was 8i % and occurred at a ph value
of 11.4. All of the total phosphorus removal results are presented in Table VI.
As expected, orthophospriate was readil.y removed (as shown y Tables VII and
VIII), particularly the soluble orthophospnate. Soluble ortho hosphate re-
movals of 90—95% were consistently achieved when the pH was in the 10.3 — 11,4
range. As with the total phosphorus, increased removals of orthophosphate
correlated with higher pH values. At pH 11.4, % removal of orthophosphate
was achieved.
* See Summary of Lime Precioitation Field Test Conditions,” Item A—l in
Aopendi x
27
-------
TABLE VI
REMOVAL OF TOTAL PHOSPHORUS
Test No.
Influent
Supernatant
pH
Influent
Supernatant
Concentration
(mg P/liter)
Reactor Vessel
pH after Lima
Addition
Reactor Vessel
Effluent
Concentration
(mg P/liter)
Percent
Removal
Pilot Plant
Effluent
nH
Pilot Plant
Effluent
Concentration
(mg P/liter)
overall Process
Percent Removal
A. Tests
Made Under Normal
Operatino Conditlons*
16
20
18
19
3
4
5
7
8
17
2
7.1
7.2
7.3
7.3
7.3
7.4
7.3
7.2
7.3
7.3
7.3
145
144
143
143
139
140
142
141
141
149
135
10.8
10.8
11.2
11.2
11.4
11.4
11.4
11.4
11.4
11.4
11.7
26.2
25.0
22.7
21.9
21.8
19.8
18.8
18.4
20.5
21.3
20.5
82
83
84
85
84
86
87
87
85
86
85
10.5
10.4
10.8
10.7
11.3
11.3
11.2
11.2
11.1
11.3
11.8
28
26
26
23
23
23
21
20
24
22
23
81
82
83
84
84
84
85
86
83
85
83
AVERAGES FOR NORMAL RUNS:
I
142
11.3
21.5
—__85
11.1
24
84
B. Tests Made Under Non—Normal Operatini Conditions*
12
14
6
15
9
10
11
13
1
7.3
7.2
7.2
7.3
7.3
7.3
7.3
7.2
7.4
142
135
138
152
149
140
143
90
154
9.7
10.7
10.8
11.2
11.4
11.5
11.6
11.8
12.3
27.3
26.0
28.1
21.0
20.3
18.7
18.4
12.2
20.9
81
81
80
86
87
86
87
86
87
8.9
10.2
10.2
10.5
11.1
11.2
10.9
11.5
12.3
29
28
30
22
23
22
21
13
19
80
79
78
86
85
84
85
86
87
AVERAGES FOR NON-NORMAL RUNS:
I 7. J 138
11.2
21.4
85
10.8
23
-I
83
C. Supplemental Tests *
21 7.1 148
22 7.2 145
23 7.2
11.2
11.0
**
22.7
28.5
**
85
80
**
**
9.5
**
**
**
**
**
**
* Refer to Appendix for explanation of Normal, Non—Normal, and Supplemental Operatinp Conditions, Item A—3
** Malysis not performed.
28
-------
TABLE VII
REMOVAL OF TOTAL ORThOPHOSPHATE
Test No.
Influent
Supernatant
pH
Influent
Supernatant
ConcentratIon
(mg P/liter)
Reactor Vessel
pH After Lime
Addition
Reactor Vessel
Effluent
Concentration
(mg P/liter)
Percent
Removal
Pilot Plant
Effluent
pH
Pilot Plant
Effluent
ConcentratIon
(mo p/liter)
Overall Process
Percent Removal
A. Tests Made Under Normal Operatina Conditlons*
16
20
18
19
3
4
5
7
8
17
2
7.1
7.2
7.3
7.3
7.3
7.4
7.3
7.2
7.3
7.3
7.3
--
**
**
**
106
107
103
108
103
**
107
10.8
10.8
11.2
11.2
11.4
11.4
11.4
11.4
11.4
11.4
11.7
**
**
**
11
10
9
9
11
**
11
*
**
**
90
91
91
92
89
**
89
10.5
10.4
10.8
10.7
11.3
11.3
11.2
11.2
11.1
11.3
11.8
**
**
**
12
11
11
10
14
**
12
**
**
**
**
89
89
89
91
87
**
88
AVERAGES FOR NORMAL RUNS:
7.3
106
11.3
10
90
11.1
12
,
89
B. Tests Made Under Non—Normal Operating ConditlOnS*
12
14
6
15
9
10
11
13
1
7.3
7.2
7.2
7.3
7.3
7.3
7.3
7.2
7.4
**
CC
105
**
111
105
CC
CC
117
9.7
10.7
10.8
11.2
11.4
11.5
11.6
11.8
12.3
**
17
10
10
10
84
91
90
92
8.9
10.2
10.2
10.5
11.1
11.2
10.9
11.5
12.3
C C
CC
18
CC
12
12
CC
CC
9
CC
CC
83
CC
89
89
CC
CC
93
AVERAGESFOR NON-NORMAL OPERATING CONDITIONS:
7.3 110
11.2
12
89
10.8
13
89
C. Supplemental Tests*
.
21
22
23
7.!
7.2
7.2
CC
CC
11.2
11.0
CC
CC
CC
*C
**
CC
**
CC
95
CC
**
CC
CC
CC
C*
CC
* Refer to Appendix for explanation of Normals Non-Normal, and Suoplemental Operating Conditions, Item A—3
** Analysis not performed.
29
-------
TARLE VIII
REMOVAL OF SOLUOLE ORTHOPIIOSPHATO
Test No.
Influent
Supernatant
p 11
Influent
Supernatant
Concentration
(rag P/liter)
Reactor Vessel
H After Lime
Addition
Reactor Vessel
Effluent
Concentration
(rig P/liter)
Percent
Remeval
Pilot Plant
Effluent
pH
Pilot Plant
Effluent
Concentration
‘ 1fl9 P/liter)
Overall
Process
Percent
Rer’mval
A. Tests M
ade Under Normal
Operating Conditi
ons*
16
20
18
19
3
4
5
7
8
17
2
7.1
7.2
7.3
7.3
7.3
7.4
7.3
7.2
7.3
7.3
7.3
65
71
68
65
62
63
67
73
66
69
62
10.8
10.8
11.2
11.2
11.4
11.4
11.4
11.4
11.4
11.4
11.7
4.6
5.1
4.3
3.2
3.6
2.2
2.1
2.8
3.4
4.4
6.9
93
93
94
95
94
96
97
96
95
94
89
10.5
10.4
10.8
10.7
11.3
11.3
11.2
11.2
11.1
11.3
11.8
7
7
5
6
4
5
4
4
6
4
6
89
90
92
91
94
92
95
94
92
94
91
AVERAGES FO
8 NORMAL RUNS:
7.3 j
66
1L3
3.9
94
11.1
5
92
8. Tests M
ade Under Non—Normal Operatlno Condltlons*
12
14
6
15
9
10
11
13
1
7.3
7.2
7.2
7.3
7.3
7.3
7.3
7.2
7.4
62
63
69
61
66
68
66
46
73
9.7
10.7
10.8
11.2
11.4
11.5
11.6
11.8
12.3
5.0
7.0
45
2.1
1.8
2.0
4.0
3.0
5.3
92
89
94
97
97
97
94
94
93
8.9
10.2
10.2
10.5
11.1
11.2
10.9
11.5
12.3
12
14
10
5
4
4
5
2
5
80
78
85
92
94
94
92
97
94
AVERAGES FOR
NON-NOIOIAI. RUNS:
7.3 64
11.2
3.7
94
10.5
7
90
C. Supplemental Tests*
21
22
23
7.1
7.2
7.2
82
84
11.2
11.0
2.6
3.5
**
97
96
**
“
9.5
**
**
**
**
**
**
• Refer to Appendix for explanation of Normals Non-Normal end Supplemental Ooerating Conditions, Item V 3
** Analysis not performed.
30
-------
On the basis of average removal efficiencies under normal operating conditions,
1.04 pounds of soluble orthophosphate phospnorus and 2.01 pounds of total
phosphorus were removed per 100 pounds of slaked lime used.
Data relative to suspended solids removal under various operatinq conditions
are presented in Table IX. Average S.S. removal under normal operating condi-
tions was 64%, from 2251 mg/liter to 796 mg/liter. There was a correlation be-
tween Reactor Vessel pH (after liming) and suspended solids removal efficiency.
When the p11 was raised above pH 10.8, the suspended solids removal could be
correlated with the initial suspended solids concentration of the influent
supernatant liquor. Higher suspended solids removal efficiencies generally
coincided with higher initial supernatant suspended solids values. As Table IX
indicates, no selective removal of either organic or inorganic material occurred
during lime precipitation. The initial supernatant particulate matter was 75%
volatile, and the unflocculated suspended solids remaining in suspension after
lime treatment and settling was 76% volatile.
Table X sumarizes the results of lime precipitation treatment. TOG and COD
removals, as indicated by Table X, averaged 49% and 48%, respectively. TOG
removal was fairly constant over the normal range of operatinrt conditions. The
Reactor Vessel effluent contained only 33% as much total carbon as the initial
input supernatant. About 5% of the total carbon decrease occurred during car-
bon dioxide stripping. Total carbon removals were about 5% lower at non-
normal pH values (i.e. pH values out of the 10.8 — 11.8 range). emova1 of
total carbon closely paralleled total solids reduction, as is to be expected.
31
-------
TABLE IX
REMOVAL OF SUSPENDED SOLIDS
TEST
NO.
INFLUE14T SUPERNATANT
REACTOR VESSEL
PILOT PLONT EFFLUENT -
OVERALL
PROCESS
PERCENT
S.S.
REMOVAL
pH
S.S.
Conc.
(mn/liter)
Percent
Volatile
S.S.
ni-I After
Lime
Mdition
Effluent
S.S. Conc.
(r’c/liter)
Percent
S.S.
Rerioval
Percent
Volatile
S.S.
oil
S.S.
Conc.
(mg/liter)
Percent
Volatile
s.s.
A. Te
sts Made U
nder Bonsai
Omeratino Conditions*
16
20
18
19
3
4
5
7
8
17
2
7.1
7.2
7.3
73
7.3
7.4
7.3
7.2
7.3
7.3
7.3
2240
2310
2160
2320
2740
2670
2560
2050
1660
2210
1840
76
76
74
75
77
75
75
77
68
79
76
10.8
10.8
11.2
11.2
11.4
11.4
11.4
11.4
11.4
11.4
11.7
920
1050
950
860
850
835
605
605
825
890
364
60
55
56
63
69
69
76
70
50
60
80
80
74
69
72
80
80
79
75
77
81
69
10.5
10.4
iu.e
10.7
11.3
11.3
11.2
11.2
11.1
11.3
11.3
850
905
865
745
735
715
765
615
1045
750
700
72
70
61
73
78
72
67
72
57
72
65
62
61
60
68
73
73
70
70
37
66
62
-AVERA
DES FOR NOR
7.3
MAL RU3S:
[ 2251
75
11.3
796
64
76
11.1
790
69
64
8. Tests Made Under Non—Mornal Ooeratina Conditions*
12
14.
6
15
9
10
11
13
1
7.3
7.2
7.2
7.3
7.3
7.3
7.3
7.2
7.4
2150
1790
2260
1930
3520
1640
2110
1010
3200
76
72
76
73
76
75
74
51
74
9.7
10.7
10.8
11.2
11.4
19.5
11.6
11.8
12.3
345
1000
300
800
750
600
402
317
580
84
42
65
59
79
70
81
69
82
63
80
73
75
76
77
71
63
62
8.9
10.2
13.2
10.5
11.1
11.2
10.9
11.5
12.3
330
670
720
605
785
686
562
442
415
63
67
61
73
68
59
65
66
63
86
61
68
69
78
61
73
55
87
AVERA
DES Fl l NON
7.3
—NORMAL RUNS:
2172
72
11.2
610
70
71
10.8
568
65
71
C. Supplemental
21 7.1
22 7.2
23 7.2
Tests
2200 81 11.2 1010 54 72 **
3775 78 11.0 1105 69 81 95
** *4 *4
**
**
**
-
**
*.*
4*
*4
* Refer to Apoendix for exolenitlor of Normal • Non-Normal • and Suooletnental Operating Conditions, Item A-3
Analysis not cerforeed.
32
-------
( )
* Tests done after the pre_plasned 20-test evaluation schedule was coopleted.
TABLE
EFFECTIVENESS OF LIME TREATMENT AND SETTLING
TEST REACTOR REACTOR
VESSEL VESSEL
SETTLING pH AFTER
TIME LIME
(Mm.) ADDITION
PERCENT PERCENT
TOTAL SOLUBLE
PHOSPHORUS ORTHO—
REMOVAL P04
REMOVAL
PERCENT
TOTAL
ORTHO—
PD 4
REMOVAL
PERCENT
SUSPENDED
SOLIDS
REMOVAL
PERCENT
VOLATILE
SUSPENDED
SOLIDS
REMOVAL
PERCENT
TOC
REMOVAL
PERCENT
COD
REMOVAL
PERCENT PERCENT
TOTAL ALKALINITY
CARBON REMOVAL
REMOVAL
PERCENT PERCENT PERCENT PERCENT PERCENT
HARDNESS CALCIUM MAGNESIUM TOTAL ORGANIC
REMOVAL REMOVAL REMOVAL SOLIDS NITROGEN
REMOVAL REMOVAL
A. Tests Made Under Normal OperBtlOfl Conditions
16
20
18
19
3
4
5
7
8
17
2
60
60
60
60
60
60
60
60
60
60
60
10.8
10.8
11.2
11.2
11.4
11,4
11.4
11.4
11.4
11.4
11.7
81 89
82 90
83 92
34 91
84 94
84 92
85 95
86 94
83 92
85 94
83 91
**
-
**
89
89
89
91
87
88
62
61
60
68
73
73
70
70
37
66
62
4
64
67
69
72
74
74
71
47
69
61
43
39
36
58
69
39
62
61
43
48
41
49
41
50
50
*
*-*
**
52
**
65
56
62
68
12
71
11
71
69
69
71
62
68
67
70
57
77
61
73
66
68
57
40
49
53
54
*
40
12
70
10
30
.*
**
**
**
Ca
26
85
87
88
89
Ca
a.
**
90
**
38
37
42
42
50
46
45
46
38
43
4
60
46
46
47
Ca
**
‘
53
Ca
AVERAGES FOR NORMAL RUNS
11.3
84
92
76
64
67
49
48
67
66
47
30
88
43
50
B. Tests Made Under Non-Nonmial
Operating
Conditions
12
14
6
15
9
10
11
13
1
60
60
60
60
60
120
90
60
60
9.7
10.7
10.8
11.2
11.4
11.5
11.6
11.8
12.3
80
79
lB
86
84
85
85
66
87
80
78
86
92
94
92
92
97
94
--
**
83
89
--
**
“
93
85
61
68
69
78
61
73
56
87
87
64
74
69
80
72
77
43
89
4
36
48
43
52
46
39
69
49
42
45
53
**
52
60
-
55
68
64
68
71
70
70
73
69
63
64
74
81
77
73
85
75
39
7 S
33
43
28
0
-
43 68 38
15 41 37
** ** 37
36 89 43
** 5
** ** 42
18 92 45
0 88 43
** 42
42
45
46
Ca
7
56
AVERAGE FOR NON-NORMAL RUNS:
11.2
83 89
88
71
73
47
52
68
70
36
22 76 I 42
49
C. Saoo1 mmenta1 Tests*
21 30
22 45
23 60
11.2 85 97 ** 54 59
11.0 80 96 69 69
10.9 Ct ** a. a. a.
32
34
a.
a.
•
CC
a.
** ** ** CC 44 **
** ** ** *C 44 **
** a. ** a. n **
CC Analysis not performed.
-------
Orqanic nitroaen was reduced by 50% durinq line preciritation treatment. The
average alkalinity of the Reactor Vessel effluent was 3,300 me/liter, l3 ’ lower
than the initial supernatant concentration. Removal of hardness, as expected,
was best at pH 9.7. At pH 11.2 — 11.4, the hardness was reduced by 40 —
with hardness removal decreasinn rapidly to zero at H 11.8. Good renoval of
magnesium occurred throughout the 9.7 - 11.8 pH range, as indicated by Table X.
Waste sludge volumes are indicated by Table XI. A more dense sludge was pro-
duced as the pH increased, even though the amount of material removed was
greater at higher pH values. Concentrating the sludge for an additional 1 to
2 hours further reduced the waste sludge volume. The concentrated waste sludge
was found to dewater very well. A 2—inch layer of concentrated waste sludge
(6.3% solids) lost 50% of its moisture content in a 3-hour period when placed
on a 3—inch deep bed of Monterey 20—mesh sand. After 5 days, the sludge had
drained and dried to a 32% solids content. Figure 12 shows the disposal area
used for the pilot plant sludge during the testing at Irvington. No drainage
or ponding problems were encountered, even though a considerable amount of
rain fell during the six—week field test period.
The effect of different concentrations of supernatant constituents upon lime
precipitation effectiveness was investigated. An attempt was made to produce
a stronger-than-normal supernatant by fillinq the Reactor Vessel witn Irvington
34
-------
TABLE XI
u - I
SLUDGE PRODUCTION
Test No.
Reactor Vessel
pH After Lime
Addition
Initial
Settlinq
Time
(Minutes)
Settled
S ludqe
Volume
(Gallons)
Percent
Solids
Settled
Sludne
in
Sludcje
Concentration
Period
(Ninutes)
Concentrated
Sludne
Volume
(Gallons)
Percent
Solids in
Concentrated
Sludqe
Decrp se in
Net Volume
of Sludne
Produced
20
10.80
60
375
1.54
120
193
9.95
48.6
6*
10.85
60
375
1.57
120
204
9.98
45.6
1*
12.25
60
360
4.63
60
338
8.59
6.0
12*
9.65
60
330
2.57
120
264
2.54
20.0
14*
10.65
60
330
2.11
120
220
11.41
33.4
16
10.80
60
315
2.46
120
180
10,94
41.8
3
11.35
60
315
5.42
90
254
7.15
19.4
7
11.45
60
300
5.28
120
214
8.82
28.6
18
11.15
60
285
3.06
120
200
10.28
29.9
19
11.15
60
285
3.86
120
205
9.69
28.1
4
11.40
60
285
6.73
150
254
11.91
10.9
9*
11.40
60
285
6.91
90
272
4.5
2
11,70
60
285
5.51
90
232
9.52
18.5
5
11.40
60
270
4.88
150
234
5.98
13.3
15*
11.20
60
255
8.32
120
229
9.98
10.2
8
11.35
60
255
6.06
60
206
9.23
19.2
17
11.35
60
240
7.79
120
181
9.52
24.6
13*
11,75
60
218
5,54
120
191
6,03
12,4
11*
11.60
90
255
3.90
210
241
5.73
5.5
10*
11.50
-___
120 210
7,93
1260
153
16,1
26,9
* Non-Normal Runs • See Appendix 1 Item A-3
-------
FIGURE 12
WaSte Sludge Disposal Area
supernatant, allowing it to settle, and tnen replacing the non-settable portion
with an additional amount of Irvington supernatant. A weaker-than-normal
supernatant was obtained by diluting the Irvington supernatant with plant
secondaryeffluent. Table XII presents a comparison of tne results achieved.
It is interesting to note that the artificially “strong supernatant was
characterized chiefly by the increased solids concentration; phosphorus and
bC values were relatively unaffected. There was no readily apparent reason
for this This phenomenon should be further investigated in future work.
* cl.
:4 ) T. •
—‘4
36
-------
TABLE XII
EFFECT OF SUPER ATANT STRENGTH ON LIME
PRECIPITATION PERFORMANCE*
AVERAGE
DILUTED
CONCE TRATED
SUPERN/\T/\NT
SUPER ATAI’4T
(TEST NO.13)
SUPERNATA T
(TEST NO. 9)
Supernatant Temperature
83 73 82
before Lime Addition (°F)
Reactor Vessel pH after
11.3 11.8 11.4
Lime Addition
Influent Total Phosphorus
142 90 149
Concentration (mg/liter)
Removal in Reactor Vessel 85% 86% 87%
Influent Total Ortho-PO
Concentration (mg P liter) 106 ** 111
Removal in Reactor Vessel 90% ** 91%
Influent Soluble Ortho-P0 4
66 46 66
Concentration (mg P/liter)
Removal in Reactor Vessel 94% 94% 97%
Influent Suspended Solids
Concentration (mg/liter) 2,251 1,010 3,520
Removal in Reactor Vessel 64% 69% 79%
Influent TOC Concentration
1,239 1,145 1,260
(mg/liter)
Removal in Reactor Vessel 52% 67% 56%
* After 60 minutes carbon dioxide stripping and 6,000 mg/liter slaked lime
dosage. Refer to Appendix for explanation of these test conditions,
Item A-3.
** Analysis not performed.
37
-------
The “weaker” test supernatant had lesser concentrations of all constituents.
From the ‘imited data on Table XII, it appears that the effectiveness of lime
precipitation treatment was essentially the same in all cases. This suggests
that the relative degree of removal of phosphorus, S.S., and TOC is a function
of the Reactor Vessel pH level and is relatively independent of the concentra-
tion of the various supernatant constituents. It may, therefore, e desirable
to draw a “stronqer” supernatant to achieve more relative benefit per Dound of
lime used. This could possibly reduce the digester capacity required, (parti-
cularly secondary digester capacity) in a two-stage digestion system. This
premise will be more closely investigated in future work.
The effect of using lime precipitation settling times other than one-hour was
also investigated. The data, summarized in Table XIII, indicate one hour is
the optimum settling period.
In summary, sufficient information was collected to establish design criteria
for lime precipitation treatment of Irvington supernatant. Assuming prior
carbon dioxide stripping to raise the supernatant p11 to at least 8.2, a slaked
lime dosage of 6 grams per liter is required for the Irvington WTP digester
supernatant. This will normally produce a pH of 11.2 to 11.4 and will assure
that a pH of at least 10.8 is achieved. A total of 15 minutes should be
allowed for flash—mixing and flocculation. Quiescent settling for 45 to 60
minutes is indicated, For a continuous flow system, a 60-90 minute settlino
period should probably be used. A volume of sludge equal to 10 to 15% of the
treated supernatant volume will be produced when a one—nour settling period is
used; additional settlinq time will produce a lesser volume of sludge. The
38
-------
TABLE XIII
EFFECT OF REACTOR VESSEL SETTLING PERIOD
* Refer to Appendix for explanation of these test conditions, Itecn A—3.
** Analysis not performed.
‘.0
30 Minute*
45 Minute
1 Hour
1 .5 Hour
2 Hour
Settling
Settling
Settling
Settling
Settling
Test No.
21
Test No.
22
Normal
Test No.
11
Test No.
10
Operation
Reactor Vessel pH After Lime Addition
11.2
11.0
11.3
11.6
11.5
Influent Total Phosphorous Concentration
(mg/i iter)
148
145
142
143
140
Removal in Reactor Vessel
85%
80%
85%
87%
8 %
Influent Soluble Ortho-P04
Concentration (mg P/liter)
**
106
**
105
Removal in Reactor Vessel
**
90%
**
90%
Influent Total Ortho-P0 4
Concentration (mg P/liter)
82
84
66
66
68
Removal in Reactor Vessel
97%
96%
94%
94%
97%
Influent Suspended Solids
Concentration (mg/liter)
2,200
3,775
2,251
2,110
1,640
Removal in Reactor Vessel
54%
69%
64%
81%
70%
Influent TOC Concentration
(mg/liter )
1,080
1,180
1,239
1,040
1,060
Removal in Reactor Vessel
32%
34%
52%
52%
50%
-------
waste sludge dewaters well and can be readil.y disposed of on conventional sludge
drying beds. Where large volumes of suiernatant are to be treated, re—
calcination and reuse of the waste lime sludge could e advantageous.
PACKED-COLUMN AMMONIA—STRIPPING
Good-to-excellent removal of ammonia was achieved over a wide ranoe of operating
conditions. The pilot plant performance was particularly impressivt in view of
the fact that it was receiving approximately twice as much ammonia as the pilot
plant was designed for. Previous researchers (2) have reported that digester
supernatants contain an average of about 430 mg/liter of ammonia-nitrogen. T ie
Phase One work involved supernatants containing 250-boO mg/liter of 4H3-N. Tne
pilot plant ammonia-stripping system was nominally designed to handle an input
supernatant NH 3 -N concentration of 400 mg/liter, while the actual applied
NH 3 —N at Irvinqton averaged 853 mg/liter. The versatility of tile pilot plant
was therefore well demonstrated.
P monia-stripping results are summarized in Table XIV. The data are divided
into two groupings, representative test runs and non-representative test runs.
Representative test runs were those made under conditions which could reason-
ably be expected in a properly-designed supernatant beneficiation system. A
description of conditions existing during non-representative runs is included
in the Appendix. As Table XIV indicates, the average ffl3-f’1 removal under rep-
resentative operating conditions was 82%. A maximum removal of 98% was
achieved at pH of 11.6 and an air—to—water (A/w) ratio of 870 cubic feet per
gallon. Overall, 80-95% removal could be achieved when pH was in the 11.2 to
40
-------
TABLE XIV
N lONIA NITROGEN REMOVAL SW8IARY
Test No.
Influent
Supernatant
pH
Influent
SupErnatant
Concentration
( ei /1iter)
Strlppinq Column No. 1
Column Effluent
Influent Concentration
p 11 (me/liter)
Percent
Removal
Pilot Plant
Effluent
pH
Pilot Plant
Effluent
Concentretion
(na/liter)
Percent
Removal
Column
Linuid
Flow Rate
(non)
A / l
Ratio
A. Tests
Made Under Representative Conditions 0
2
16
3
7
18
8
15
4
6
22
23
11
7.3
7.1
7.3
7.2
7.3
7.3
7.3
7.4
7.2
7.2
7.2
7.3
830
925
822
794
814
824
854
839
829
879
462
871
11.1
10.8
11.4
11.4
11,2
11.4
11.2
11,4
10.8
11.0
10,0
11.6
466
452
515
343
426
308
247
278
285
00
44
39
44
51
37
57
51
63
71
67
66
91
92
96
11.8
10.5
11.3
11.2
10.8
11.1
10.5
11.3
10.2
9.5
9.6
10.9
282
255
315
158
212
210
67
99
125
71
70
18
66
72
62
80
76
75
92
38
8o
92
92
98
13.5
11.6
10.1
10.1
13.0
14.4
10.1
10.1
10.1
6.1
5.1
5.1
145
163
225
225
280
360
455
470
530
690
825
870
437
AVERAGES
FOR REPRESENATIVE RUNS:
7.3 850
11.2
292
66
10.7
157
82
10
B. lests liade Under Non- Representative Conditions 0
1 7.4 873 12.3
14 7.2 895 10.7
5 7.3 834 11.4
20 7.2 858 10.8
19 7.3 866 11.2
9 7.3 799 11.4
10 7.3 827 11.5
13 7.2 553 11.8
17 7.3 874 11.4
12 7.3 858 9.7
21 7.1 ** **
513
437
451
524
401
275
280
165
———
378
0*
41
51
46
33
54
66
66
70
. —
56
0 *
12.3
10.2
11.2
10.4
10.7
11.1
11.2
11.5
11.3
8.9
t*
308
242
265
195
179
97
119
49
195
235
**
65
73
68
77
79
88
86
91
78
73
0*
14.8
12.3
11.5
13.0
13.0
13.0
13.4
12.3
10.1
10.1
0*
145
183
185
275
275
345
345
400
455
470
0*
* For explanation of Non—Representative Conditions, see Appendix, Item A—4.
Analysis not perforn d.
-------
11.4 range, at an A/I ’! ratio of 350 — 450 cubic feet per qallon. A p of
11.4 — 11.6 was normally required to assure at least 8 % 4H 3 -N removal. The
data surnarized in Table XIV indicate qenerally that NH 3 -N rehioval efficiency
increases as the pH is raised, and/or as the A/W ratio is increased.
It may be seen from Table XIV that most of the NH 3 - removal occurred in tne
first stripping column. For the tests run under representative conditions,
the removal in the first strippinci column averaged 66% and overall removal
through both columns averaged 82%. That is, four—fifths of the 11H 3 —N removal
took place in the first strippinri column. Since the pilot plant aniaonia-
stripping is done in a counter—flow system, the first column NH 3 -d removal
was achieved using air which was already partially saturated with NH 3 -N after
passing through the second column. Therefore, Run #17 was made using only one
column. The pH was 11.3, and the A/W ratio was 455 cubic feet per gallon.
Test #17 is comparable to Test #4, a conventional two—column test under similar
conditions. It may be seen that the single column removal (78%) significantly
exceeds the first column removal (67%) achieved in two—column series operation.
These data, taken together, reveal that the pilot plant columns provided con-
siderably more depth of stripping column media than was beinq effectively
utilized. Therefore, stripping column design for full-scale beneficiation
facilities for Irvington—type supernatants can reasonably utilize a lesser
depth (and therefore a less volume) of stripping column media. A conservative
25% reduction in the depth and amount of column media would appear to be
justified. This would mean provision of 13 cubic feet of media per gpm of
through-put and a 12-foot depth of media.
42
-------
The supernatant used in Test #13 was diluted to give a lower, and presumably
normal, i’1H3—N concentration. Ammonia removal was not siqnificantly better
than that achieved with full strenqth supernatant.
Figure 13 and Table XV indicate the increased NH 3 -H removal efficiency which is
associated with increasing air-to-water ratios. However, as A/W ratios are in
creased above 450 - 500 cubic feet per gallon, the relative benefit tends to
decrease rapidly.
Temperature data relative to anrnonia removal are presented in Taule XVI. The
ambient air temperature was not a significant factor over the temperature
range encountered at Irvington, 50° — 86°F. The air was warmed as it passed
through the blower, with cool air beinq warmed proportionally more than warmer
air. The net effect was to produce warm influent air of relatively uniform
temperature. Under the conditions at Irvington, injection of steam to raise
the temperature of the stripping column air does not appear necessary. Com-
parison of Run #16 (no steam) with Run #14 (using steam) reveals only slight
benefit from steam injection. Runs #3 and #19 also support the conclusion
that provision of steam generating facilities at Irvington is not economically
justified.
43
-------
FIGURE 13
100- — AMIIONIANITROCEN REMOVAL VS A/W RATIO
A
90-
>
0
80-
4 )
60- —
50- —
40- 1 1 I I
0 100 200 300 400 500 600 700 800 900
A
A
A
A
A/W Ratio
-------
TABLE XV
AMMONIA—STRIPPING REQUIREMENTS
Test No.
Strippino
Column
Influent
pH
A/W
Ratio
Percent
Overall
NH 3 —N
Removal
Thousands of Cubic Feet
of Air Required per Pound
of NH 3 -N Removed
A. Tests Made Under Representative Conditions
3 11.4 225 62 53.1
2 11.7 145 66 31.7
16 10.8 163 72 29.2
8 11.4 360 75 70.3
18 11.2 280 76 50.7
7 11.4 225 80 42.3
6 10.8 530 85 90.2
4 11.4 470 88 76.1
15 11.2 455 92 69.3
22 11.0 690 92 102.3
23 10.9 825 92 124.8
11 11.6 870 98 122.2
AVERAGES FOR REPRESENTATIVE RUNS:
B. Tests Made Under Non-Representative Conditions*
1 12.3 145 65 30.7
5 11.4 185 68 38.9
14 10.7 183 73 33.6
12 9.7 470 73 90.4
20 10.8 275 77 49.7
17 11.4 455 78 80.3
19 11.2 275 79 48.0
10 11.5 345 86 58.4
9 11.4 345 88 58.9
1.3 11.8 400 91 95.1
21 ** ** ** **
* For explanation of Non-Representative Conditions, See Appendix Iten P-4.
** Analysis not performed.
.9
45
-------
TAL3LE XVI
AMfiOrlI A SIR] O ] NG TE’IPERATURE SUMMARY
Test No.
Stripoino
Column
Influent
p11
9/14
Ratio
AMbient
Al r
Temperature
F
Compressed
Al r
Temperature
°F
Stri pinq
Column Air
Temperature
F
Percent
Overall
883.-N
Removal
Percent
Removal
Through
Column No. 1
Percent
Reimoval
Throu Rh
Column No. 2
A. Tests
Made Under Representative
Conditions
4
6
11
16
3
7
15
8
18
22
23
2
11.4
10.8
11.6
10.8
11.4
11.4
11.2
11.4
11.2
11.0
10.9
11.7
470
530
870
163
225
225
455
360
280
690
825
146
56
57
58
58
58
61
62
62
62
68
68
86
79
83
85
88
82
84
80
86
84
93
86
87
59
63
63
72
64
66
64
66
70
68
67
68
88
85
98
72
62
80
92
75
76
92
92
66
67
66
96
51
37
57
71
63
51
91
92
44
21
19
2
21
15
23
21
12
25
1
0
22
AVERAGFS
FOR REPRFS [ NIAT!VL
11.2
RUNS:
437 63
85
66
1.2
66
15
B. Tests Made Using Steamed Air
19
20
14
11.2
10.8
10.7
275
275
183
59
51
67
84
84
102
74
76
82
79
77
73
54
39
51
25
38
7?
C. Tests Made Under Other Non-Reoreseetative Conditions*
17 11.4 455 50 74 70 78 —- 7,
20 11.5 345 56 80 65 86 66 20
12 9.7 470 60 80 63 73 66 17
13 11.8 400 61 85 63 91 70 21
5
9
1
21
11.4
11.4
12.3
*.*
185
345
145
--
80
80
90
--
88
88
91
**
66
65
71
--
68
88
65
**
46
66
41
**
22
22
24
*•
• For explanation of Non—Representative Conditions, see Appendix, Itmn 4-4.
Analysis not performed.
46
-------
SECTION VIII
DISCUSSION
The data and general process performance information obtained by operating the
pilot plant at the Irvington WTP was straightforward and consistent. The re-
sulting design criteria provide a reliable basis for design of full-scale
supernatant beneficiation facilities at the Irvington NIP or at any wastewater
treatment plant producing a similar type and quality of supernatant.
IRVIUGTON WTP SYSTEM :
The Irvington plant is designed for a 10.5 NIGD flow; current flow is about 5
I GD. Since present supernatant production amounts to 15,000 — 18,000 gallons
per day, a “design” supernatant volume of 36,000 gallons per day is indicated.
Sludge is pumped to the digesters every half-hour, with the duration of pumping
controlled on a sludge—density basis by automatic sensing equipment. This re-
suits in a fairly steady and continuous supernatant discharge by displacement
from the two fixed—cover digesters. The Irvington plant has been designed to
be self-operating. It is manned by operating personnel from 8:00 AM until
4:30 PM on a six days per week basis. It is therefore desirable that superna-
tant beneficiation also be done on an “automatic” and self-operating basis.
A design flow rate of 30 gpm is indicated. Under normal design conditions,
this would permit the average daily 24-hour volume of supernatant to be pro-
cessed in a 20-hour period.
47
-------
The proposed system includes a flow—equalization tank. Supernatant would be
drawn from the flow-equalization tank and passed through the beneficiation pro-
cess at the 30 gpm design rate. Under the design conditions, the volume of
supernatant discharged to the flow—equalization tank will average 25 gpnl.
Therefore, once the beneficiation process is begun, the net outflow will exceed
the net inflow, and the tank liquid depth will gradually be reduced. . Jhen a
pre—set minimum level is reached, the entire beneficiation process will auto-
matically shut down. The process will remain off until the flow-equalization
tank has refilled to a pre-determined liquid level, at which point the bene—
ficiation process will automatically re-start. Sufficient flow-equalization
tank volume should be provided to ensure that the beneficiation process, once
started, will operate for at least several hours before the minimum tank level
is reached. Under these conditions, tne lime precipitation and ammonia-stripping
processes will operate under stable flow conditions. This should enhance the
effectiveness of the lime treatment, especially.
The flow equalization tank should have a diameter of 12.5 feet, an overall
height of 13 feet, and a cone—shaped bottom. This will provide enough volu.ie
to asst re that the beneficiation process, once begun, will operate for at
least a 4—hour period even when supernatant release is only one-quarter of the
design rate (i.e., half of the present rate). This size tank will also pro-
vide enough freeboard to accommodate temporary supernatant discharge rates in
excess of the design discharge rate.
48
-------
Carbon dioxide would be stripped out in the flow—equalization tank. At the
recommended volume, the average liquid detention period will be iell in excess
of one hour (often several hours). Pilot plant results demonstrated that an
A/W ratio of 16.5 cubic feet per gallon would produce essentially complete re-
moval of C32 and a resultant 8,2 pH. On the basis of the design supernatant
discharge rate (25 gpm), air should be supplied at a 430 cfm rate. The air
blower should be capable of operating against the maximum expected liquid depth
of about 8.5 feet of water.
A low—head 25 gpm capacity pump would be used to transfer the supernatant from
the flow-equalization tank to the flocculator/clarifier for phosphorus removal.
A chemical feeder capable of adding 90 pounds of hydrated lime per hour to the
transfer stream would be required.
Pilot plant operation determined the lime requirement to be 50 pounds per
thousand gallons (i.e., 6 gms per liter) of pH 8.2 supernatant. The overall
lime requirement would, therefore, be about 1800 pounds per day under design
conditions (total plant flow of 10.5 MGD).
Since the precipitate produced by lime treatment is predominantly calcium
carbonate, and considering that the process will operate at a constant flow
rate, a conventional upflow flocculator/clarifier unit should produce good
results. A very small commercial flocculator/clarifier tank should afford ex-
cellent settling conditions. A 10-12 foot diameter unit would provide an
overflow rate of less than 600 gallons per square foot per day and a detention
time of more than 2 hours.
49
-------
Pilot plant results demonstrated that waste sludge production would amount to
10-15% of the process through—put and would dewater very readily. For tie
ful1-sca e process at Irvington, 4000-4500 gallons per day of waste sludge can
be anticipated. This is a relatively snail volume compared to the Irvinqton
plant sludge drying and disposal facilities. It would therefore prooably
not be necessary to provide any additional sludge—disposal facilities. Also,
only a minimum amount of re—piping would be required to permit use of the ex-
isting sludge pumping facilities to deliver the waste lime sludge to the sludge
disposal area.
The effluent from the flocculator/clarifier should have a p(-( of 11.2 - 11.4
and would be pumped directly to and through the ammonia-stripping column. Pro-
viding 13 cubic feet of stripping media at a 12 foot media depth would require
32.5 square feet of cross—section area. A 6.5 foot diameter column 16 feet
high would provide the required volume and depth, including a 4 foot allowance
for column freeboard and necessary under-clearance. The design air require-
ment at an A/v! ratio of 500 cubic feet per gallon would be 15,000 cfm at 2 psi
pressure.
The effluent from the ammonia-stripping column would consitute the overall
beneficiation process effluent. At the Irvinqton plant, the treated superna-
tant could drain by gravity to the plant headworks.
50
-------
Figure 14 indicates a proposed Irvirtgton WTP supernatant beneficiation system
capable of meeting full-flow (10.5 MGI )) desiqn requirements. The system would
require the following:
a) One flow-equalization tank, equipped with air diffusion equipment
for CO 2 stripping. A tank 9.5 feet deep and 12.5 feet in diameter,
with a 3.5 foot deep conical bottom, is suggested.
b) One air blower capable of supplying 400 cfm of 5 psi air for removal
of carbon dioxide by air stripping.
c) Two low-head (10 psi) pumps of 30 gpm capacity.
d) One combination flocculator/clarifier capable of providing an over-
flow rate of less than 600 gallon/foot 2 /day and at least 1.5 hours
detention time at a 30 gpm flow rate.
e) One chemical feeder capable of feeding 90 pounds of slaked lime
Ca(OH) 2 per hour.
f) One 16 foot high by 6.5 foot diameter ammonia—stripping column.
g) 387 cubic feet of 2-inch “Intalox” saddles (stripping media).
h) One blower capable of providing 15,030 cfm of 2 psi air for
ammoni a-stripping.
51
-------
FIGURE 4
RECOMMENDED FACILI TIES FOR BE NEFICIATION
OF IRVINGTON WTP DIGESTER SUPERNATANT
—I 5000 CFM
AIR BLOWER
F OR
AMMONIA-STRIPPING
GRAVITY DRAIN TO
PLANT HEADWORKS
U,
N)
FLOW-EQUALIZATION
AND
C0 2 - STRIPPING
TANK
max. liquid
voIurne 8I0O gallons,
12.5 ftdiam.
30 GPM
WASTE SLUDGE
DISCHARGED TO
DRYING BED VIA
EXISTING PUMP
AND PIPING
-------
GENERALiZED SUPERNATANT BENEFICIATION SYSTEM FOR 50 MGD PLANT :
The data obtained through operation of the Supernatant Beneficiation Pilot
Plant at Irvington should be generally applicable to similar plants, regardless
of size. A possible supernatant beneficiation system for a 50 !1GD trickling
filter plant with good sludge handling and sluthie concentration facilities is
presented in Figure 15.
The 50 MGD plant would produce about 175,000 gallons of supernatant per day,
It can be reasonably assumed that a plant of 50 1GD size could be operated to
release the supernatant at a maximum rate of not more than 15% higher than the
average overall discharge rate. The indicated 50 iGD supernatant flow rate
for design purposes is therefore 140 gallons per minute. This is a sufficient
volume of flow to justify a full—time continuous flow system.
Use of a small foam spray, de-foamant chemical or proper tank baffling could
eliminate or control foaming difficulties during air—stripping of carbon
dioxide. This would permit a reduced detention time in the carbon dioxide strip-
ping vessel. Therefore, a 30-minute stripping period at an air flow of 16 cfm
per square foot of liquid surface area (i.e., 800 cfm for each 50 square feet of
surface area) could be used. The total stripping air requirement, at an A [ J
ratio of 15 cubic feet of air per gallon of through-put, would be 2100 cfm. A
tank 13 feet in diameter with a 5 foot operating water depth would suffice.
Under the circumstances of the design situation (steady, continuous supernatant
discharge), gravity flow to and through the flocculator/clarifler can be
53
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FIGURE 5
TYPICAL
SUPERNATANT BENEFICIATION
FACILITIES FOR 50 MGD PLANT*
I 2100 CFM I
AIR BLOWER —
FOR C0 2 -STRIPPING
] 70000 OE M
AIR BLOW IR
TO PLANT
HEAL WORKS
INFLUENT
SUPERNATANT
u - i
MAKE-UP
LIME
CARBON
DIOXIDE
STRIPPING
4200 GALLONS
13 ft. r i diarn.
$
LIME
FEEDER
420 lbs/hr
*PRODUCING IRVINGTON-TYPE SUPERNATANT
-------
assumed. A chemical feeder capable of feeding at least 420 pounds of hydrated
lime per hour would be needed. Ten thousand pounds of lime would be required
per day. At this rate of use, re—calcining and lime reuse is indicated to avoid
or minimize sludge disposal problems. Previous investigators (4) have reported
that re-calcining produces reclaimed lime at a cost about equal to the price of
new lime; however, re—calcining greatly reduces the excess solids disposal re-
quirement and is thereby justified.
A flocculator/clarifier unit 25 feet in diameter and 8 feet deep iould provide
an overflow rate of less than 600 gallons per square foot per day and a detention
period of just under 3 hours.
After flowing from the diciester and tnrough the flocculator/clarifier by gravity,
the supernatant would need to be pumped to and through the ammonia—stripping
column. A 140 gprn medium-head (40—50 feet of water) pump would be required.
A total of 1820 cubic feet of 2—inch Intalox saddles would be needed for ammonia
stripping. A media depth of 12 feet would require 151 square feet of stripping
media cross—sectional area. This could be a column 14 feet in diameter or a
12.5 foot by 12.5 foot square column. An overall column height of 16 feet
should be ample. The ammonia—stripping air requirement at an A/W ratio of 500
cubic feet per gallon would be 70,000 cfm of low pressure (2 psi) air.
55
-------
Equipment and facilities required for supernatant beneficiation at a 50 MGD
trickling filter plant would include the following:
a) A 13 foot diameter by 5 foot deep tank for stripping carbon dioxide
from the raw supernatant. The tank should have provisions for con-
trolling foam.
b) One air blower capable of supplying 2100 cfm of 5 psi air for strip-
ping carbon dioxide.
c) One medium-head 140 cipm pump.
d) A flocculator/clarifier capable of providing an overflow rate of less
than 600 gallons per square foot per day and at least 1.5 hours de-
tention time at a 140 gprn flow rate. This would require a unit about
25 feet in diameter and 8 feet deep.
e) Chemical feeder capacity sufficient to feed hydrated lime at a rate
of 420 pounds per hour.
f) A lime re—calcining system capable of handling 22,000 gallons of lime
sludge (6% solids) per day.
g) One 14 foot diameter by 16 foot high ammonia-stripping column.
h) 1820 cubic feet of 2 inch “Intalox” saddles (stripping media).
i) One blower capable of providing 70,000 cfm of 2 psi air for arnonia—
stripping.
-------
SECTION IX
ECOWO1IC CuWSIU RATIOWS
Removal of nutrient materials by means of the superiiatant beneficiation .process
offers a number of economies. The dollar-cost advantages are mostly associated
with the high concentrations at which nitrogen and pnosphorus occur in digester
supernatants.
Pilot plant operation required slightly less than 50 pounds of hydrated lime
per pound of phosphorus removed from Irvington WTP supernatant. When phosphorus
is present at low concentrations (8-10 mg/l), a lime requirement of 58 pounds
per pound of phosphorus removed has been reported (3). It therefore appears
that removal of phosphorus from concentrated waste streams could be accomplished
at a slightly lower operating (i.e., chemical) cost.
Lime precipitation capital costs are reduced in proportion to the increased
concentration of phosphorus. Tank volume required per pound of lime removed
is 93% less than is required for “conventional” lime precipitation (where tne
phosphorus concentration is low, 15 mg/i or less). This could represent a major
cost savings for situations where only partial removal of wastewater phosphorus
is required.
Similar economies exist relative to nitrogen removal. Where 4H 3 -N is present
at low concentrations (25—35 mg/i), it has been reported (3) that 480 cubic
feet of air per gallon was required to achieve 60-95% ammonia removal
57
-------
efficiency. This amounts to a strippinq—air requirement of 1,7 3,8 million cubic
feet of air per pound of arnonia nitrogen removed. Under circumstances where
removal of only the N11 3 —N in the digester supernatant is acceptable, only
83,000 cubic feet of air are required per pound of W1 3 -H removed. Tne capital
cost for tankage is likewise greatly reduced.
The incidental improvement in overall supernatant quality also can be con-
sidered an operating economy. The 50-65% removal of suspended solids, TOC,
COO, and organic nitrogen which occurs in the course of the phosphorus and
nitrogen removal means a reduction in the net load applied to the secondary
treatment facilities. Thus the removal of nutrient materials from the super-
natant has the side benefit of incrementally increasing the overall treatment
plant efficiency.
58
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SECTIO X
ACKWOWLE DGEMEI4TS
The work described in this report was performed by the Environmental Engineering
Department of the FMC Corporation Central Engineering Laboratories. The need
for an investigation of this type was originally perceived by personnel of the
FWQA Advanced Waste Treatment Laboratory. The project was sponsored by the
Federal Water Quality Administration of the U. S. Department of the Interior
under the terms of Contract No. 14-12-414.
Field testing and operation of the pilot plant was done by James E. Ournanowski,
who also contributed significantly to the preparation of this report.
Initial process conceptualization and preliminary laboratory investigations
were done by R. A. Fisher, 1. F. Hobbs, and R. W. Prettyman.
Other t,EL personnel who made significant contributions were F. F. Sako, W. G.
Palmer, J. P. Pelmulder, W. F. Conley, W. A. Hendricks, C. Najera, N. Meister,
T. Liddicoat, and A. Charlebois.
The complete cooperation of the Union Sanitary District, Fremont, California,
is gratefully acknowledged. Particular thanks are expressed to Art Duarte,
Lee Doty, John Silva, and Joe Vierra.
The continuing attention, interest, and guidance of Mr. Edwin F. Darth, FWQA
Contract Offi cer, is gratefully acknowledged.
/ George E. Bennett,
Engineer-in-Charge
59
-------
REFERENCES
(1) Environmental Engineering Progress Report R—2826, “Phase I: Development
of a Process to Remove Carbonaceous, Nitrogenous and Phosphorus laterials
From Anaerobic Digester Supernatant and Related Process Streams”, Central
Engineering Laboratories, FMC Corporation, Santa Clara, California (lay,
1969).
(2) Masselli, Joseph W., et.al., “The Effect of Industrial Wastes on Sewage
Treatment”, New England Water Pollution Control Commission, Boston,
Massachusetts (1965).
(3) Smith, C. E. , and Chapman, R. L. , “Recovery of Coagulant, i itrogen Removal,
and Carbon Regeneration in Waste Water Reclamation”, FWPCA Report, WPD-85
(June, 1967).
(4) Cuip, Russell L., “The Status of Phosphorus Removal”, Public Works Magazine
(October, 1969).
61
-------
P PPEflDI X
63
-------
ITEM A-1
SUMMARY OF LIME PRECIPITATION FIELD TEST CONDITONS
TEST NO. TEST CONDITIONS
1 The normal operating sequence* was followed,
except that slaked lime dosage was 6,840 mgI
liter and sludge concentration period was
only one hour.
2 Normal operating sequence, except that the
sludge concentration period was 90 minutes.
3 Normal operating sequence, except that the
sludge concentration period was 90 minutes.
4 Normal operating sequence, except that the
sludge concentration period was 2—1/2 hours.
5 Normal operating sequence, except that the
sludge concentration period was 2—1/2 hours.
6 Normal operating seiuence, except that the
carbon dioxide stripping time was only
30 minutes.
7 Normal operating sequence.
8 Normal operating sequence, except that the
sludge concentration period was only one hour.
9 Normal operating sequence, except that the
sludge concentration period was 90 minutes.
10 Normal operating sequence, except that the
settling period was 2 hours and the sludge
concentration period was 21 hours.
11 Normal operating sequence, except that the
settling period was 90 minutes and the
sludge concentration period was 3—1/2 hours.
* 4ormal operatinci sequence is carbon dioxide stripping for 60 minutes at
550 cfm 1 lime dosage of 6,000 mg/liter, 15 minutes flocculation, 60
minutes settling, and a 2 hour sludge concentration period.
65
-------
sur•1:IARY OF LLIE PRECIPITATION FIELD TEST CO DITIO, S
TEST NO . 1L LU DITIOfJS
12 Normal operating sequence, except that the
carbon dioxide stripping time was 15 minutes
and the lime dosage was 4,500 mg/liter.
13 Normal operating sequence, except that the
lime dosage was 4,500 mg/liter.
14 Normal operating sequence.
15 Normal operating sequence, except that the
carbon dioxide stripping time was 45 minutes.
16 Normal operating sequence, except that steam
was added to the carbon dioxide stripping air.
17 Normal operating sequence.
18 Normal operating sequence.
19 Normal operating sequence.
20 Normal operating sequence, except that the
lime dosage was 5,840 mg/liter.
21 Normal operating sequence, except that the
settling time was 30 minutes.
22 Normal operating sequence, except that the
settling time was 45 minutes.
23 Normal operating sequence, except that the
carbon dioxide stripping time was only
15 minutes.
66
-------
ITEM A-2
EXPLANAT I ON OF NON—REPRESET1TAT I VE
AMMONIA STRIPPING CONDITIONS
TEST NO. TEST CONDITIONS
1 Stripping column influent pH was abnormally high at
pH 12.3.
5 Stripping column influent was partially batch stripped
in the reactor vessel prior to passing it through the
columns.
9 Approximately 50% more particulate solids were present
in the stripping column influent.
10 Stripping column influent allowed to stand in the reactor
vessel overnight before passing it through the columns.
12 Stripping column influent pH was abnormally low at pH 9.7.
13 “Half-strength’ test; NH 3 —N content was 553 mg/liter
versus the average concentration of 835 mg/liter.
14 Steam utilized to add heat and moisture to the ammonia
stripping air.
17 Only one ammonia stripping column utilized.
19 Steam utilized to add heat and moisture to the ammonia
stripping air.
20 Steam utilized to add heat and moisture to the aPii onia
stripping air.
21 Test used only to check carbon dioxide stripping rates
at various air flows. No an rionia stripping done.
67
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SAM FL
V•29
--- - - . — -—v —-i
WASTE V -2 i V-i
I
V-I 2
— .-- _w . j — -.-i
V-H
VIASTE__
V- 10
SAMPLE
V-2 8
DECANT
TAN K
// H
\ // k -2
\ /‘ H-I -
V35\/
‘>. - ‘AT i P
IETER
V
--V- i V 2
2 )‘ H AMPLE
PUMP PUMP
V-30
STEAM LINE
- -----
r LEGEND;
P--PUMP
V — VALVE
H —QUICK-DISCONNECT COUPLING
SW- FLOAT VA L VE
ITEM A—3
FUIICTIONAL PIPING UIAGRA:i OF
TRAI LER-MOUNTEL) SUPERNATANT
L ENEFICIATION PILOT PLANT
U
V -3 1
P [ f ’ C T I’) N TA N K - Al P I .- N E
SW - ------ .- — - - - - -. - -—
- V E N T
V33
HME
AV I NC
-iii
C - ’
t. [ LftJ
B L ‘DW E P
VN
2000 GALLON
PLASTIC TANK
ON GROUND FOR
TREATED
SUPER NATANT
-------
12/16/69
ITEM A—2
DIGESTER SUPERWATAIT TRAI LER EQUIPMENT LI ST
CE 45570
EQ PMEUT DESCRIPTION SUPPLIER MANUFACTURER
Corning Model 5 pH Meter Scientific Products, Corning Glass Works,
with electrodes* Menlo Park, Calif. Scientific Instruments,
Iledfield, Mass. 02052
Electrodes (spare set) Scientific Products Corning Glass Works
for above meter. Corning Menlo Park, Calif. Scientific Instruments
Series 500. Reference Iledfield, Mass. 02052
electrode Corning No.
476106, pH electrode
Corning No. 476105
Malsbary Steam Generator Malsbary Ilanufacturing Co. Same
Model 20D* 845 92nd Avenue
Oakland, Calif. 94603
Fischer and Porter 10A3565A G. 1. Cooke Co. Fischer and Porter Co.
65 Rotameter Tube No. 935 Pardee Avenue Warminster, Penn.
FP—2—27—G—lO/83 Berkeley, Calif. 94710
Float No. 2-GNSVGT98
100% Flow — 63.1 gpm
Liq. Spec. GIL — 1.0*
Master Combination Padlocks Orchard Supply Hardware Master Lock Company
Lab Lock Code No. X2ll91 720 West San Carlos Milwaukee, Wisconsin
Combination: R.-12—L—22—R-36 San Jose, Calif.
Electrical Cabinet Lock
Code No. X2l171
Combination: fl_6_L_20_R_34*
Hastings Air—Meter Model JHS Associates Hastings—Raydist Inc.
No. G—ll with 5—27 probe* P. 0. Box 1894 Hampton, Virginia 23361
San Leandro, Calif. 94577
ftii erican Water Meter Roberts and Brune American Meter Controls
Series 650 20780l6T American Meter Controls Buffalo, Hew York
A Niagra Liquid rleter* 1832 Rollens Road
Bur1inga ie, Calif. 94010
* Operating Manuals in File
69
-------
12/16/69
EQUIPMENT DESCRIPTION
SUPPR
MA UFACTURER
147 Rochester Industrial
Thermometer ilodel 1740
3” Diameter dial
Stainless Steel Sink and
Counter Top Sections
25” Deep with 3—12”
Backs p1 ash*
California Instruments Co.
351 10th street
San Francisco, Calif. 94103
Sears Roebuck and Co.
Commercial Sales Department
1350 West San Carlos
San Jose, Calif.
Coronado Swimming Pool
15’ x 48”
Kiddie Uorld
3640 Stevens Creek Blvd.
San Jose, Calif.
HPE, Inc.
225 Acacia Street
Colton, Calif.
Jabsco Model 6400—05
One 8681-14 and
two 8674_3*
Coker Pump and Equip Co.
1089 3rd Avenue
Oakland, Calif. 94607
Jabsco Pump Co.
Costa Mesa, Calif.
Robbins and Meyers
Iloyno Pump Type CDQ
Fram lL6 Form VT
Serial No. A_6332_1*
C. U. Bosv,ell Co.
767 S. 16th Street
Richmond, Calif.
Robbins and Meyers, Inc.
Springfield, Ohio
Gorman-Rupp Self-Priming
Centrifugal Pump
Size 3 x 3, 7—3/4” impeller
Serial No. 446853
Model lb. 83C2B
Coker Pump and Equip.
1089 3rd Avenue
Oakland, Calif. 94607
Co.
Gorman—Rupp Co.
Ilansfield, Ohio
General Electric Tn-clad
Induction Ilotor (Gorman-
Rupp Pump) Model 5K184BL220
No. LD H.P. — 5 Serv. Fac. -
1.0, Volts — 230/460, Phase 3,
Cycle — 60, Amp - 14.2/7.1,
RPM 1745, Time Rating — Cont.
40 Deg. C Max. Amb. Frame -
184T, Type - K, Code - H,
Ins. Class — B, NEMA Des. — B,
Shaft End Brg. AFBFIA - 35BCO2XP
Opp. End Brg. AFBMA — 25BCO2XP
Coker Pump and Equip. Co.
1089 3rd Avenue
Oakland, Calif. 94637
General Electric
Ft. Wayne, Indiana
* Operating Manual in File
70
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12/16/69
ErUIPMEr T DESCRIPTIOi4
SUPPLI ER
MAUUFACTURER
General Electric A—C
flotor (Steam Generator
H.P. — 1/4, FR — 48,
Model 5KC37 KG] 84
219500, RPM 1725
pH — 1, S.F. — 1.0,
Temp. Rise — 55°C,
Volts 115, Code — F l,
Amps - 5.2, Cycle — 60,
Time Rating — Cont.
Serial Mo. WXD
General Electric Supply
530 ilartin Avenue
Santa Clara, Calif.
95050
General Electric
Ft. Wayne, Indiana
General Electric
Tn—Clad Induction Motor
Model No. 5K364BK134B1
Serial Ho. KE 415016,
Frame - 364T, H.P. - 60,
cycle — 60, pH - 3,
F.L. RPM 3555, Ser. Fac. —
1.0, Time Rating — Cont.,
Volts - 460/230, F.L. Amps -
144/72, Type - K, NEMA Class
Design — B, Code — G, Ins.
Class B, flax. Amb. - 40°C,
Drive End AFBf1A Brg. 70BC03,
Opp. Drive End AFBVA Brg.
60BC03*
Buffalo Forge
C/U Richard Stities, Inc.
139 Mitchell Avenue
So. San Francisco, Calif.
94080
General Electric
Schenectady, Wew York
U.S. Electrical Motor (T .zo)
(Tower Pumps) H.P. 1, pH - 3,
Cycle — 60, Frane - 143T,
Volts — 460/230, Amps —
3.6/1.8, Ser. Fac. — 1.0,
RPM 1710, Model No.
F-l500—02—l6l, Iris. Class — B,
Rating — Cont., 40°C flax. Amb.
Shaft End Brg. AFBMA — 25BC02XS3
Opp. End Brg. AFBM/\ — 17BC O2X3*
Horsford Brothers
1775 So. 1st Street
San Jose, Calif. 95112
U.S. Electric Motors
Ililford, Conn. and
Los Angeles, Calif.
* Operating Manual in File
71
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12/16/69
EQUIPMENT DESCRIPTION SUPPLIER MANUFACTURER
U.S Electrical Varidrive Horsford Brothers U.S. Electric Motors
Motor, HP. - 1, P 1 — 3 ’ 1775 So. 1st Street tlilford, Conn. and
Cycle - 60, Volts - 460/230 Oakland, Calif. 95112 Los Angeles, Calif.
Amps - 4.6/2.3, Gear Ratio
2.79, Motor RPM 1725, RPM
Mm. — 154, RPM flax. — 1540
Ins. Class - B, Frame - 6-56-5,
Type VAV—JF—Gfl, Design — B,
Code L, Cont. Rating — 40°C
Max. Amb. Serial No. HF —
1030285, Nominal Power
System Voltage 480/240
Dayton Three Phase A—C Motor W. Grainger, Inc. Dayton Electric Mfg. Co.
(Moyno Pump) LR24684, 1260 No. 13th Street Chicago, 49, Illinois
Model NO. 2 933—C, H.P. — 1, San Jose, Calif.
RPM — 1740, Cycles — 60,
Frame - 182, Duty - Cont.
Risc — 55°C, Tyøe - PF,
Ser. Fac. — 1.0, Code —
Motor Ref. — 72145-C NP
Volts - 220/208/440
Amps - 3.6/1.8
Buffalo Blower and Motor Richard Stites, Inca Buffalo Forge Co.
Frame, Frame Size - 405U 139 Mitchell Avenue Buffalo, New York 14204
27” Wheel Counter—clockwise So. San Francisco, Calif.
Top, Horizontal Discharge 94080
Trailer, Brown, used 27’1/2” X Redwood Reliance Co.
9l’-5/3” flatbed. Removed 141 Helmar Avenue
stake pockets and ground smOoth, Cotati, Calif. 94928
straightened side rails. Ilew
1—1/8” water—proof plywood deck
installed outside of main frame
rails, rear shortened to
approximately 24” behind axle
center, no rear hitch, hoses
terminated at axle, old rear
cross member to be delivered
loose. Steam cleaned and painted
with enamel, 4 serviceable tires
as is, skid plates on landing gear.
After all installations, final
trailer length is 30’ 5”.
72
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1/21/70
EQUIPMENT DESCRIPTION SUPPLIER MANUFACTURER
General Electric HT Quiet General Electric Supply General Electric
Transformer. Model No. 530 Martin Avenue Ft. Wayne, Indiana
9121B1006, Hz — 60, Santa Clara, Calif.
KVA - 10, Temp. Rise,
— 115, Serial — KE N.P. —
183796
73
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1
BIBLIOGRAPHIC
Central Engineering Laboratories, Flit Corporation, Development of a Pilot Plant Ce Demonstrate Removal ACCESSION NO.
of Nutrient and Carbonaceous Materials from Panaerobic Digester Supernatant, final Report, EaQA Contract
Ho. 14—12-414, May, 1970.
ABSTRACT
Digester uapernatant contains high concentration of nitrogen and phouehoruo. Also, poor quality saperna— KEY WORDS:
tant discharged from an anaerobic digester con have an adverse effect on tne overall efficiency of a waste—
water treatment plant.
Sludge Treatment
Under the FWQA opensorship, the Central Engineering Laboratories of the fAt tomnoration, undertook to
baud and demonstrate the operation of a onique, trailer—mounted, and completely onlf-contained pilot plant. Supermatant Nutrient Removal
The pilot plant io designed to ineestigate tne improvement of digeoter ounernatant quality, aith particalar
emphasis on the remonal of nitrogen and phooohorus, The pilot n lant treatnent sequence consists of cerooe Phospoorus Removal
dinnide removal via air—stripping, lime precipitation of phesnhorus and caroonaceous purticalate matter,
and removal of nitrogen by pecked—tower anemnia—utrinoing, Nitrogen Removal
The pilot plant wan operated over a tao-month period at a trickling filter nlvnt where Ceo-stage anaerobic nia Stripping
digeetion io practiced. The pilot plant ooerated in a reliable and consistent faonion wits respect to both
the mocoanical performance and the proceon data ootained. A wide range of noerating ccnditions was in—
eentigated in a convenient and effective manner.
It was foend that 83—gUS of oaonrnatant nh000horus could bn removed at a lime dosage equal to 50 pounds
of hydrated line per pound of phosphorus removed, Overage anronia—oitrogen removal was dOt, achieved at an
air flow rate equal to 83,003 cubic feet of air per pound of lO3 J removed.
Normal lime precipitation removed above one—naif of toe oupernutant TOO, LOP, and Organic ditrogen. The
aeerage decrease in suopended solids vau 84%.
This report is submitted In fulfillment of Contract In. 14—12—414 (Program An. 17310 ft b) between the
Federal Water Quality A ninistration and the Central Engineering Laboratories of FTC Cornaratino.
I —
BIBLIOGR APhIC
Central Engineering Laboratories • ff0 Cvrporation, Deuelopeenc of a Pilot Plant to bemonstrate Removal 800EOSION NO.
of Nutrient and Carbonaceous Materials from 7 naerobic Digester Supernatant, final teoart, FOQA Contract
No. 14-12—414, May, 1970.
ABSTRACT
Digester sapernatant contains nigh concentration of nitrogen and pnouehorus. Also, poor quality superna— KE WORDS:
tent discharged from an anaerobic digester can have an uoeerse effect on the overall efficiency of a waste—
water treatment o lant.
Sludge Treatment
Under the FWQA sponsorship, tne Central Cnginenrino Laboratories nf the fAt Corporation, undercook to
beild and demonstrate the operation of a unique, trailer—mounted, nod corpletely self—contained pilot plant. Supernatant Nutrient Removal
The pilot ploot is designed to investigate toe imor000mmot oi oipestem oupemnacenc iuulity, with particular
emphasis on the removal of nitrogen and phoooboruo. The piloc slant oreuorvnt svbuence consists o carson Phosonorus Removal
dionide remoaal via air—otripping, lime precipitation of phossnomus use corpcndcenus particulate matter,
and remioeal of nitrogen by packed—tower anwhonia—scriooing. Nitrogen Removal
The pilot plant was noerated over a two—month oeriod at a tr:cklinp filter nlonc whore two—stage anaerobic Ammonia Stripping
digesCiemn is practiced. The olloc plant onerated in a reliaple and consistent fashion with respect to L0CO
the mecnuoical oerformance and the process data ostuineo. 3 aide range of operating conditions was in—
nestigated in a convenient and effeotiee manner.
It was found that 83—9S of supernatant pn000horus could bo resoved at a lime dosage equal to bO pounds
of hydrated line per sound of phosphorus removed. Peerage anrooia—nitrogen removal was d2P, uooieved at an
air flow rate equal Ce 83,303 cubic feec of air oem pound of A 3 - ;: ronowod.
Bonsai lime precipitation removed aboue one-oalf of tie ouoemnatunt ICC, LOP, and Organic itrogen. Tne
aeerage decrease in suopanded solids was t4%.
ibis report in submitted in fulfillment of Contract .0. 14—12—414 (Program u. 17313 fcf) between toe
Federal Water Quality Atrimistration and tne Central bogineerimT Laboratories of fit Comnoracion.
r — — — — —- — — 1
Central Engineering Laboratories, ff0 Corporation, Ceoelmpment of a Pilot Plant to bemonstrace Removal ACCESSION SD.
of Nutrient and Caromnaceous Materials from Pwiaerooic digester Supemnatunc, final hesort, F.Qb Contract
ho. 14—12—414, May, 1970.
Digester supernatant conoains high concentration of nitrogen and 0 10sphorus. Also, poor quality superna- KEg WORDS:
Cant discharged from an anaerobic digester can have an adverse effect on the onerull efficiency of a vance—
water treutoent n lant,
Sludge Treatment
Under the faQA sponsnruhip, tne Central kngineoriwo Laborotonies of tse fit Ccrnorution, undertook to
baud and demonstrate the operation of a unilue, trailer—mounted, and comnletelm snif—contuined pilot plant. Supemnatant NutrIent Removal
The pilot plant is designed to investigate tne irpmoeersnc of dipenter ousereutenc puuliCy, with particular
emphasis em the renoeal of nitrogen and phosphorus. Tne pilot plumC treaTment snquence coosists of carton Phospnnrus Removal
dioxide removal via uir—ucrioping, lime precisitution of phcssnorus and curoohoceous narticalute netter,
and removal of nitrogen by packed—tower amimvnia-strioniom. Nitrogen Removal
The oiiot plant was onerated over a two—momth oemicd at a Cnickling filtor slant acorn twc—sCoge unaerooic Ammonia Strippieg
digestion is practiced. The oilot plant ooerutvc in a reliebln and consistent fasnion wits resseot to totn
the mecoanloal oerfonnaece and the process data ubtoine e. A wide ma ngo of onerucing conditions uas in—
eestlgated in a onneenient and effectiuv manner.
It was found that 83—95% of uupemnotant nhosoborus could n ro ineed at a lime dosage eouul to no poundu
of hydrated lure oer omund of phosphorus remoevo . teeruge ammonia—nitrogen rercuul was dOt, ucnieeed at an
air flow rate equal to 83,333 cubic feet of air oem pound of .n3 mempeud.
Normal lime precipitation removed above one—nulf of tee supemndtunt TLC, LAP, and wmganic .itmogeo. lie
aeerape decrease in suspended solids was 64t.
This report uu submitted In fulfillmont of CunCracc ‘In. 14—12—414 (Progru—’ n. 17010 fc C) between Con
Federal Outer Quality 7 ninisCrution and tee Central bnginderihm Lanorutcmivs of flL Corporation.
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Accession Field & Group —
SELECTED WATER RESOURCES ABSTRACTS
INPUT TRANSACTION FORM
Or anizat’on
Central Engineering Laboratories, FIIC Corporation
6 T ,elopTnent of a Portable Pilot Plant to bemonstrate Removal of Carbonaceous,
Nitrogenous, and Phosphorus Materials from Anaerobic Digester Supernatant and
Similar Process Streams
10 I Author(X3
—i
Bennett, George E.
16 Project Designation
Progam No. 17010 FK.A/Contract No. 14—12—414
i.—
Note
N/A
Citation
N/A
23 Descriptors (Starred First)
I *Djg t Supernatant, *Amonja Stripping, Nutrient Removal
25 Identifiers (Starred First)
*Phosphorus Removal, *Nitrogen Removal, Sludge Treatment
Digester suoernatant contains high concentrations of nitrocien and ohosohorus.
fl Abstract Also, poor quality supernatant discharged from an anaerobic digester can have an
adverse effect on the overall efficiency of a wastewater treatment plant.
Under FWQA sponsorship, the Central Engineering Laboratories of the FMC Corporation under-
took to build and demonstrate the operation of a unique, trailer—mounted, and completely
self—contained pilot plant. The pilot plant is designed to investigate the improvement of
digester suoernatant quality, with particular emphasis on the removal of nitrogen and phos-
phorus. The pilot plant treatment sequence consists of carbon dioxide removal via air-
stripping, lime precipitation of phosphorus and carbonaceous particulate matter, and re-
moval of nitrogen by oacked—t er arwnonia—stripping.
The pilot plant was operated over a two-month period at a trickling filter plant where two-
stage anaerobic digestion is practiced. The pilot olant operated in a reliable and consist-
ent fashion with respect to both the mechanical performance and the process data obtained.
A wide range of operating conditions was investigated in a convenient and effective manner.
It was found that 80—95% of supernatant phosphorus could be removed at a lime dosage equal
to 50 pounds of hydrated lime per pound of phosphorus removed. Average amnionia-nitroqen re-
moval was 82%, achieved at an air flow rate equal to 83,000 cubic feet of air per pound of
NH 3 —N removed. Normal lime precipitation removed about one—half of the supernatant TOO,
COD, and Organic Nitrogen. The average decrease in suspended solids was 64%.
Abstractor In. t,tution
Bennett, George E. Centra ] ngin rjng Laborato j, fljccc rporatinn
WR 1C2 REV JUEN 1969) SENT TO: SATER RESOURCES SC ENT E )C e4POFMRTION CENTER
WRS C U.S. DEPARISIENT OF THE INTERIOR
WASP-IINOTON D C 2T040
U.S. GOVESNSEUT PRINTING OFFICE: 1970 0—000-096
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