United State*
Environmental Protection
Agency
Municipel Environmental Research EPA-600 2-79-007
Laboratory February 1979
Cinoimrti OH 45268
Reaearch and Development
Biological-Chemical
Process for
Removing
Phosphorus at
Reno/Sparks, NV
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RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development, U.S. Environmental
Protection Agency, have been grouped into nine series. These nine broad cate-
gories were established to facilitate further development and application of en-
vironmental technology. Elimination of traditional grouping was consciously
planned to foster technology transfer and a maximum interface in related fields.
The nine series are:
1 Environmental Health Effects Research
2. Environmental Protection Technology
3. Ecological Research
4. Environmental Monitoring
5. Socioeconomic Environmental Studies
6. Scientific and Technical Assessment Reports (STAR)
7. Interagency Energy-Environment Research and Development
8. "Special" Reports
9. Miscellaneous Reports
This report has been assigned to the ENVIRONMENTAL PROTECTION TECH-
NOLOGY series. This series describes research performed to develop and dem-
onstrate instrumentation, equipment, and methodology to repair or prevent en-
vironmental degradation from point and non-point sources of pollution. This work
provides the new or improved technology required for the control and treatment
of pollution sources to meet environmental quality standards.
This document is available to the public through the National Technical Informa-
tion Service, Springfield, Virginia 22161.
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EPA-600/2-79-007
February 1979
BIOLOGICAL-CHEMICAL PROCESS FOR
REMOVING PHOSPHORUS AT RENO/SPARKS, NV
by
R. F. Drnevich
Union Carbide Corporation, Linde Division
Tonawanda, NY 14150
Grant No. 804931
Project Officer
E. F. Earth
Wastewater Research Division
Municipal Environmental Research Division
Cincinnati, OH 45268
MUNICIPAL ENVIRONMENTAL RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U. S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OH 45268
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DISCLAIMER
This report has been reviewed by the Municipal Environmental Re-
search Laboratory, U. S. Environmental Protection Agency, and approved for
publication. Approval does not signify that the contents necessarily reflect
the views and policies of the U. S. Environmental Protection Agency, nor
does mention of trade names or commercial products constitute endorsement
or recommendation for use.
ii
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FOREWORD
The Environmental Protection Agency was created because of increas-
ing public and government concern about the dangers of pollution to the health
and welfare of the American people. The complexity of that environment and
the interplay between its components require a concentrated and integrated
attack on the problem.
Research and development is that necessary first step in problem solu-
tion and it involves defining the problem, measuring its impact, and search-
ing for solutions. The Municipal Environmental Research Laboratory develops
new and improved technology and systems for the prevention, treatment, and
management of wastewater and solid and hazardous waste pollutant discharges
from municipal and community sources, for the preservation and treatment of
public drinking water supplies, and to minimize the adverse economic, social,
health, and aesthetic effects of pollution. This publication is one of the
products of that research; a most vital communications link between the re-
searcher and the user community.
. This report describes those features of process theory, plant design,
and operational control necessary to remove phosphorus from an activated
sludge system employing a biological-chemical process.
Francis T. Mayo, Director
Municipal Environmental Research
Laboratory
iii
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ABSTRACT
This demonstration project was initiated with the purpose of establish-
ing the capability of the PhoStrip system to remove phosphorus on a full scale
activated sludge system and compare these results to those obtained on a
pilot scale system.
This process employs the capability of activated sludge microorgan-
isms to take up and release phosphorus as a result of being cycled between
aerobic and anoxic conditions. During the aerobic period in the aeration
basin the phosphorus in the wastewater is removed by the biomass. The
sludge is then separated from the phosphorus-free wastewater in the second-
ary clarifier. A portion of the return sludge from the clarifier is pumped to an
anoxic stripper tank where the phosphorus is released to the water surround-
ing the sludge. This phosphorus-containing water is then separated from the
sludge either through further thickening of the sludge or through elutriation.
The supernatant from the anoxic zone is treated with lime to precipitate the
phosphorus and the sludge from the anoxic zone is returned to the aeration
basin.
The pilot and full scale testing was performed at the Reno/Sparks
Joint Water Pollution Control Plant located in Sparks, Nevada. The pilot
scale system consisted of a 0.11 m3/hr. diffused air activated sludge system
designed to incorporate the PhoStrip system. This system was designed to
produce optimum performance with the elutriation mode of separating the
phosphorus from the sludge in the anoxic zone (stripper tank). The full scale
system consisted of a temporary modification of the Reno/Sparks plant.
Treating one-third of the plant flow (25,000 m3/d) was first tested using the
thickening mode of separating phosphorus from the sludge in the thickener.
Later, two-thirds of the plant flow (51,000 m3/d) was treated utilizing the
elutriation method.
The PhoStrip system demonstrated the capability of reducing the ef-
fluent total phosphorus to less than 1 mg/1 on both the pilot and full scale
systems. The factors involved in designing the process to achieve these
levels were discussed and recommendations were made as to the proper
selection of conditions to achieve the desired performance. A method of pre-
dicting lime requirements and chemical sludge production was proposed. The
overall cost of the system relative to conventional mineral addition systems
was discussed.
^
iv
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This report was submitted in fulfillment of EPA Grant No. R80493J-
01 by the City of Sparks, Nevada under the sponsorship of the U.S. Environ-
mental Protection Agency. This report covers the period October 26, 1976 to
January 30, 1977, and work was completed January 30, 1977. The report was
prepared by Union Carbide Corporation under subcontract to Sparks, NV.
v
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CONTENTS
Foreword iii
Abstract iv
Figures viol
Tables x
Acknowledgments xii
1. Introduction 1
2. Conclusions 13
3. Recommendations 15
4. Process Theory 16
5. Description of Facilities 36
6. Results & Discussion 45
7. Lime Requirements, Chemical Sludge Production, and
Chemical Sludge Dewatering 85
References 94
Appendix (Economic Evaluations) 97
Appendix A (Raw Data Summary) 1J5
vix
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FIGURES
Number Page
1 Generalized PhoStrip schematic 3
2 Sludge recycle option employed at Seneca Falls, N.Y 3
3 Stripper supernatant elutriation option 7
4 Elutriation with liquids having low phosphorus concentrations . 7
5 Sludge poly phosphate granules before and after anoxic period
in stripper tank 19
6 Phosphorus mass balance - 10 mgd plant size 21
7 Mass balance around the stripper tank 23
8 Stripper tank mass balance, sludge recycle modification. ... 24
9 Elutriation efficiency for the sludge recycle and elutriation
systems 25
10 Components of total flux settling tanks 27
11 Variables affecting performance of the PhoStrip process .... 32
12 Schematic diagram - PhoStrip pilot plant, Reno/Sparks, Nevada 37
13 General flow schematic - Reno/Sparks Water Pollution Control
Plant 39
14 PhoStrip system flow diagram - sludge recycle system, Reno/
Sparks Water Pollution Control Plant. 42
15 PhoStrip system control diagram - low phosphate elutriation
system, Reno/Sparks Water Pollution Control Plant 43
(Continued)
viii
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FIGURES
(Continued)
Number Page
16 Daily influent and effluent phosphorus concentrations -
PhoStrip Pilot Plant, Reno/Sparks, Nevada 54
17 Sampling points and flow diagram - Reno/Sparks, Nevada . . 59
18 Reno/Sparks full scale phosphorus data obtained during mini-
mum flow period 64
19 Reno/Sparks full scale phosphorus data obtained during maxi-
mum flow period 65
20 Flow diagram of PhoStrip LPE system at Reno/Sparks, Nevada 71
21 Stripper tank and elutriant distribution system 72
22 Reno/Sparks full scale phosphorus data for LPE system. ... 77
23 Phosphorus uptake rate constant versus temperature - Reno/
Sparks, Nevada 82
24 Elutriation efficiency for the LPE modification 83
25 Lime requirements to achieve a given pH level 88
26 Comparison of calculated and measured sludge production . . 91
IX
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TABLES
Number Page
1 Summary of PhoStrip pilot plant results 4
2 Results of phosphorus removal test at Seneca Falls, N.Y.. . 5
f
3 Pilot plant oxygen activated sludge system at Tonawanda,
N.Y 9
, 4 Results of pilot scale demonstration programs 11
5 Analytical monitoring of the PhoStrip pilot plant, Reno/
Sparks, Nevada 46
6 Phase I operating conditions at the PhoStrip pilot plant,
Reno/Sparks, Nevada 48
7 Phase I average analytical results at the PhoStrip pilot plant,
Reno/Sparks, Nevada 49
8 Phases II and III operating conditions at the PhoStrip pilot
plant, Reno/Sparks, Nevada 51
9 Phases II and III average analytical results at the PhoStrip
pilot plant, Reno/Sparks, Nevada 53
10 Phase average phosphorus balance data at PhoStrip pilot
plant, Reno/Sparks, Nevada 56
11 Weekly analytical schedule - Reno/Sparks, Nevada 58
12 Operating conditions for the PhoStrip sludge recycle system-
full scale testing at Reno/Sparks, Nevada 61
13 Analytical results for the PhoStrip sludge recycle system full
scale testing at Reno/Sparks, Nevada 63
14 Phosphorus balance data for the full scale testing at Reno/
Sparks, Nevada - PhoStrip sludge recycle system 67
x
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TABLES
(Continued)
Number Page
15 Sludge phosphorus concentration of the control system -
full scale testing at Reno/Sparks, Nevada 68
16 Analytical schedule for full scale testing at Reno/Sparks,
Nevada - PhoStrip LPE system 73
17 Operating conditions for full scale testing at Reno/
Sparks, Nevada - PhoStrip LPE system 74
18 Analytical results for full scale testing at Reno/Sparks,
Nevada - PhoStrip LPE system 76
19 Phosphorus balance data for full scale testing at Reno/
Sparks, Nevada - PhoStrip LPE system 79
20 Kinetic constants and elutriation efficiencies at Reno/
Sparks, Nevada 81
21 Summary of lime dosage requirement studies of the
stripper supernatant 87
22 Chemical sludge production from stripper supernatant . . 90
23 Filter leaf test result of calcium phosphate sludge formed
from stripper supernatant 92
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ACKNOWLEDGMENTS
We would like to thank Mr. Robert Churn of the City of Sparks, Nevada
and the Reno/Sparks Joint Committee for permitting us to use their fine
facilities and their invaluable aid in implementing the modifications re-
quired to convert their plant into a PhoStrip system.
The Reno/Sparks Joint Water Pollution Control Plant personnel demon-
strated a great spirit of cooperation, without which the project could not
have been started. The highly responsible supervision of the facilities by
E. G. Davis is greatly appreciated.
We would especially like to thank Mr. Lawrence E. Peirano of Kennedy
Engineers and Kennedy Engineers whose good engineering judgment was re-
sponsible for introducing the PhoStrip system to the Reno/Sparks Joint Water
Pollution Control Plant, and who pioneered the full scale testing at Reno/
Sparks. This program could not have been performed without their contribu-
tions.
Our appreciation is also extended to Mr. Louis M. LaClair and Dr.
L. C. Matsch of Union Carbide Corporation whose valuable direction was
instrumental in the performance of the program and the preparation of this
report. We would also like to acknowledge the efforts of Dr. Michael S.
Gould and Mr. John Antolik of Union Carbide for their many contributions to
the daily operation of the system.
The assistance of Mr. Edwin F. Earth, Project Officer for the Office
of Research and Development, U.S.E.P.A., was invaluable throughout the
program and greatly enhanced the quality of this report.
We would also like to thank Mr. Gary K. Koeppel and Ms. Esther H.
Ferris for their help in the preparation of this document.
Xil
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SECTION 1
INTRODUCTION
A variety of methods have been developed to remove phosphorus from
wastewaters. Typically, phosphorus removal is achieved by precipitating
phosphates with salts of iron, aluminum, and calcium (lime). The EPA
Process Design Manual for Phosphorus Removal (1) indicates that precipitation
can be accomplished in the primary clarifier, as part of the secondary treat-
ment process, or as a tertiary treatment process. The use of lime is generally
limited to primary clarifier addition or tertiary treatment because precipitation
with lime is pH dependent and secondary systems, i.e., activated sludge, do
not perform well at the pH range best suited to the use of lime (9l pH-?12).
The capability of the activated sludge process to remove substantial
quantities of phosphorus from wastewaters without the aid of direct chemical
addition is a fairly recent discovery. However, the capacity of micro-
organisms to accumulate phosphorus is not a new observation. Volutin (a
metachromatic granule composed of poly phosphates) was first observed by
Ernst (2) in 1888. Since that time, microorganisms such as bacteria, fungi,
yeasts, algae and protozoa have been isolated and shown to contain intra-
cellular volutin granules (3-7). Organisms as common as E. coli are capable
of producing polyphosphate containing granules under proper environmental
conditions (8). Srinath et al (9) concluded that protozoa of the Epistylia sp.
could be related to excess phosphorus uptake in activated sludge systems.
Feng (10) demonstrated that the operating conditions of the activated sludge
process affected the rate and capacity of the process to remove phosphorus.
Later, Sekikawa et al (11) studied the conditions which were responsible for
the release of phosphorus by activated sludge. One of Sekikawa's conclu-
sions was that lack of dissolved oxygen was a major cause of orthophosphate
release. Levin (12) utilized the information obtained by these investigators,
as well as the results of studies he performed (13), to produce a process
capable of biochemically removing phosphorus from wastewater. This process
has been named the PhoStrip^ system.
This process utilizes the ability of microorganisms to take up and re-
lease phosphorus as a function of environmental conditions. Under aerobic
* PhoStrip is a registered service mark of Union Carbide Corporation.
-------
conditions these organisms accumulate more phosphorus than that required for
growth, while under an anoxic environment the excess phosphorus is released
back to a liquid phase. Modifying the activated sludge process so that these
characteristics could be used efficiently results in the concentration of phos-
phorus into a small sidestream, which can be economically treated with lime
to precipitate phosphorus, as shown in Figure 1.
Early development of the process was undertaken by Biospherics, Inc.
of Rockville, Md. This work resulted in a general outline of the operational
parameters required for efficient phosphorus removal. Table 1 presents a sum-
mary of the type of phosphorus removal demonstrated by the process on a pilot
scale. These data indicates that very efficient phosphorus removal may be
achieved with chemical addition to the side stream flow.
This development work was highlighted by the full scale data obtained
on a 12,100 m3/d (3.3 mgd) plant at Seneca Falls, N.Y. (13) Conversion of
the plant to the PhoStrip process was facilitated by the fact that, at the time
of the study, the raw wastewater flow was only 3800 m^/d (1 mgd). This
enabled the plant to handle the full plant flow through one of the two reactor
trains, thus freeing a primary clarifier to provide the anoxic environment re-
quired for the return sludge to release excess phosphorus. The tank providing
this anoxic zone has been labelled the "stripper tank." The use of a single
train to treat the entire wastewater flow also permitted the test to be run on a
system that was much nearer the design hydraulic loading for the Seneca Falls
plant. The use of the primary clarifier as the stripper tank was expeditious;
however, it was significantly oversized relative to the wastewater flow
entering the aeration basins. Table 2 presents a concise summary of the data
obtained during the first thirty days of operation at Seneca Falls. This repre-
sents the period of operation during which the performance of the process was
intensively monitored. The recycle flow rates presented are typical of a
system utilizing sludge thickening in the stripper tank to produce the phos-
phate-enriched supernatant. The data on plant performance indicates that very
high removals of both BOD^ and phosphorus were achieved. The lime dosage
is reflective of the chemical requirements anticipated for many full scale
systems.
From testing of the process at Washington, D. C., it was determined
that in the thickening mode of operation most of the phosphorus release
occurred after the solid-liquid separation function was completed. Therefore,
in order to achieve the supernatant phosphorus levels and the overall per-
formance at Seneca Falls, the process was modified as shown in Figure 2.
Sludge that had already released phosphorus was returned to the inlet line of
the stripper, thus bringing the released phosphorus in contact with the liquid
that would form the supernatant. This operational modification resulted in
the ability to remove a significant fraction of the influent phosphorus through
the supernatant stream leaving the top of the stripper tank. The remaining
-------
WASTEWATER
PRIMARY
CLARIFIER
WASTE
SLUDGE
AERATION
SECONDARY
CLARIFIER
EFFLUENT
DIRECT RECYCLE
UME
STRIPPER
SUPERNATANT
STRIPPER
STRIPPER
FEED
WASTE
SLUDGE
STRIPPER RETURN
FIG. I . Generalized PhoStrip schematic
WASTEWATER
PRIMARY
CLARIFIER
LIME
AERATION
SECONDARY
CLARIRER
EFFLUENT
DIRECT RECYCLE
STRIPPER
SUPERNATANT
STRIPPER
STRIPPER
FEED
WASTE
SLUDGE
SLUDGE
RECYCLE
STRIPPER RETURN
FIG. 2.. Sludge recycle option employed at Seneca Fa I Is, NY.
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TABLE 1. SUMMARY OF PHOSTRIP PILOT PLANT RESULTS
Results of Analysis of Raw Data Obtained from Biospherics, Inc.
Location
Synthetic Waste
Washington, D. C.
Piscataway, Md.
Chicago, 111.
Phase
Duration ,
days
27
30
30
10
Total Phosphorus
Raw Waste, Effluent,
mg/1 mg/1
9.6
6.8
5.1
3.0
0.1
0.8
0.5
0.3
Removal,
percent
99
88
90
90
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TABLE 2. RESULTS OF PHOSPHORUS REMOVAL TEST
AT SENECA FALLS, N. Y.
Plant Flow, m3/d (mgd) 3400 (0.9)
Return Flows, percent of raw flow:
Sludge to Stripper 24
Sludge to Aeration from Stripper 10
Supernatant to Primary Clarifier 14
Total Suspended Solids, mg/1:
Mixed Liquor 1,440
Sludge to Stripper 7, 840
Sludge to Aeration from Stripper 15,910
Influent, mg/1:
BODs 158
Total Phosphorus 6.3
Effluent, mg/1:
BOD5 *4
Total Phosphorus .6
Plant Performance:
BOD5 Removal, percent 98
Total Phosphorus Removal, percent 91
Lime Dose, Stripper Supernatant, mg/1 of supernatant 170
Lime Dose, prorated to mg/1 of raw flow 24
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phosphorus removal was achieved with the waste biological sludge.
Early in 1974 Union Carbide Corporation began preliminary testing to
determine the feasibility of this process. Initial studies were performed
utilizing the flow scheme presented in Figure 1. A 0.95 1/s (15 gal/min.)
pilot scale oxygen activated sludge system operating on Tonawanda, N.Y.
wastewater served as the basic unit to which the PhoStrip process was
added. This system was a four stage covered unit using pitch blade turbine
surface aerators for mixing and mass transfer. High purity oxygen (99.5% O^
was added to the first stage and the gas flowed cocurrently with the liquid
from stage to stage. Both the mixed liquor and the oxygen depleted gas
were discharged from the last stage of the reactor.
As with the work at Seneca Falls, the ability of the process to remove
phosphorus depended on the ability to produce a supernatant stream with a
high concentration of soluble phosphorus. It was found that low concentra-
tions of dissolved oxygen or nitrate resulted in the inhibition of the release
of phosphorus in the stripper tank. In general, the tests using the configura-
tion shown in Figure 1 resulted in poor overall performance. Further testing
utilizing the schematic presented in Figure 2 improved performance, but did
not result in consistent high quality effluents. The nature of the system
shown in Figure 2 was such that the supernatant from the stripper was pro-
duced through thickening. Because of solids flux limitations, this mode re-
sulted in the operation of the secondary clarifier without a sludge blanket.
The lack of a sludge blanket in the clarifier permitted significant amounts of
oxygen to enter the stripper tank via the clarifier underflow. Since the sludge
recycle scheme tends to make the stripper tank approach a completely mixed
vessel, the dissolved oxygen coming in from the secondary clarifier may have
been distributed well enough throughout the tank to significantly inhibit the
rate of phosphorus release. However, as reported later on page 57, Peirano
(31) successfully utilized this flow scheme at Reno/Sparks, Nevada.
To overcome the problems which resulted from a completely mixed
stripper tank, the flow schemes presented in Figures 3 and 4 were tested.
The modification shown in Figure 3 utilizes recirculation of stripper super-
natant to wash or elutriate phosphorus from the solids leaving the stripper
tank. Under this mode of operation, the sludge solids were allowed to pro-
gress through the tank in a plug flow manner while the supernatant and the
liquid around the solids that was removed with the underflow solids tended to
approach a completely mixed configuration. As with the sludge recycle sys-
tem, the ability of this system to achieve equal concentrations of phosphorus
in the supernatant and in the liquid surrounding the sludge leaving the stripper
increased with increases in recirculation rates. At high recirculation rates a
net upward flow of liquid occurs in the stripper tank, thus reducing the sludge
thickness above the point of liquid injection. This coupled with the dissolved
oxygen that entered the supernatant tended to reduce the efficiency of this
technique although it was generally more efficient than the sludge recycle
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YATER
KKIMARY
CLARIFIER
TWA:
SLU
LT/
i o^
i
3TE
DGE
i
AERATION
DIRECT RECYCLE
STRIPPER ST-RFEDE
k SUPERNATANT -«
' STRIPPER
STRIPPER RETURN |f
< . -'
EFFL
SECONDARY *
CLARIFIER
^ WASTE
SLUDGE
R
1
ELUTRIANT
RG.3. Stripper supernatant elutriation option.
WASTEWATER
PRIMARY
CLARIFIER
wASTE
SLUDGE
REACTOR
CLARIFIED
WASTE
'SLUDGE
(CHEMICAL
AERATION
AtRATlUN
DIRECT RECYCLE
STRIPPER
SUPERNATANT
SECONDARY
CLARIFIER
STRIPPER
STRIPPER RETURN
EFFLUENT
. >•
SLUDGE
PRECIPITATED STRIPPER SUPERNATANT
(LOW PHOSPHORUS CONTENT)
_J
ALTERNATE ELUTRIANT
FIG.4. Elutriation with liquids having low phosphorus concentrations.
( precipitated stripper supernatant)
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mode. The dissolved oxygen entered the elutriant through diffusional mass
transfer at the air liquid interfaces at the surface of the tank and as a result
of flow over the discharge weir of the tank. The first column of Table 3 sum-
marizes typical data obtained utilizing the stripper supernatant recyle scheme.
Figure 4 presents a modified system as discussed by Matsch et al (14)
and Drnevich et al (15). This system utilizes a liquid containing relatively
low concentrations of both phosphorus and suspended solids to elutriate the
sludge in the stripper and produce a supernatant high in dissolved phosphorus.
In Figure 4 the elutriant is either the final effluent or the supernatant from the
reactor clarifier which is used to perform the lime addition-precipitation
function. This elutriation method overcomes the problems associated with the
other techniques in that much lower flows are required to achieve equivalent
elutriation efficiencies as defined in equation 1.
mass of phosphorus in supernatant , .
total mass of phosphorus released in the stripper tank
The performance of this system more closely approximates a countercurrent
extraction system where plug flow characteristics are observed for both the
liquid and solid phases in the stripper. In this configuration small concen-
trations of dissolved oxygen or nitrate in the elutriant have less of an effect
on the rate of phosphorus release because only the solids in the bottom of the
tank come in contact with the inhibitors. At that point, most of the phosphor-
us has already been released from the sludge and must merely be displaced
to the supernatant. Table 3 presents a summary of two phases of operation
where the system described by Matsch et al (14) was employed, compared to
stripper supernatant recirculation. During the phase represented by the data
in column two, the elutriant employed was supernatant from the stripper after
the phosphorus was removed via lime addition. The last column presents
data from a system employing final effluent as the elutriant. In comparing
the performance of these systems with the data from the process employing
stripper supernatant recirculation, it is important to note that countercurrent
type systems produce higher elutriation efficiencies at significantly lower
elutriation flow rates.
Similar testing of the process on air activated sludge pilot plants on
synthetic and Tonawanda wastewaters confirmed the superiority of the
countercurrent elutriation type system with respect to the ability to achieve
high stripper supernatant and low final effluent phosphorus concentrations.
This system also eliminates the need for thickening in the stripper tank be-
cause the supernatant is formed from the elutriant. This reduced dependency
on thickening permits the stripper tank to be designed with significantly
lower cross sectional area and volume.
Subsequent to the initial testing of the process at Tonawanda, N.Y.,
8
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TABLE 3. PILOT PLANT OXYGEN ACTIVATED SLUDGE SYSTEM
AT TONAWANDA, N. Y.
Mode of Operation
Duration of Phase, days
Feed Rate, 1/s (gpm)
Recycle Rate , % of Q
Stripper Feed, % of Q
Stripper Return to Aeration, °/
Stripper Supernatant Rate, %
Elutriation Rate, % of Q
Stripper
Supernatant
Used for
Elutriation
12
.76 (12)
25.
25.
6 of Q 12.
ofQ 13.
25.
Precipitated
Stripper
Supernatant
Used for
Elutriation
20
.95 (15)
40.
19.
18.
9.
8.
Final
Effluent
Used for
Elutriation
23
.95 (15)
33.
20.
19.
11.
9.
Anaerobic Retention Time, hr.
(based on stripper return to
aeration)
Total Suspended Solids, mg/1:
Mixed Liquor
Stripper Feed
Stripper Return
Effluent
BOD5/ mg/1:
Influent
Effluent
Total Phosphorus, mg/1:
Influent
Effluent
Stripper Return (soluble)
Stripper Supernatant
9.9
78
10
5.3
0.5
59
35
6.1
100
10
7.5
0.5
36
58
6.3
2,929
14,740
31,590
10
5,189
18,600
18,140
7
4,400
17,500
17,540
10
120
18
11.1
0.8
60
78
Elutriation Efficiency (e)
.40
.45
.43
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the performance capabilities of the process have been demonstrated via pilot
plant programs on wastewaters from Texas City, Texas; Adrian, Michigan;
Southtowns, N.Y.; Brockton, Mass. (16); and Findlay, Ohio. Table 4 contains
some of the important characteristics and data obtained from the various
studies. Each of the programs employed a variation of the countercurrent
elutriation system. The Texas City full scale plant has a State-imposed ef-
fluent phosphorus limitation of less than 2.0 mg P/l, and the BODs and sus-
pended solids levels have to be maintained at less than 10 mg/i. The data in
Table 4 shows that the phosphorus removal was achieved with no difficulty,
but the effluent would have to be filtered because the effluent suspended
solids achievable by activated sludge systems are higher than the State's
limitation.
As is the case at Texas City, the activated sludge system in opera-
tion at Adrian is not able to reduce effluent suspended solids to meet State
standards. Therefore, tertiary filtration will be employed. Since 88%'of the
effluent phosphorus is in the form of suspended solids, tertiary filtration to
less than 10 mg/1 suspended solids would result in an effluent total phos-
phorus of less than 1 mg/1.
The pilot plant program performed on the wastewater from Southtowns,
N.Y. differs from the previously discussed studies in that the pilot plant was
run at Tonawanda, N.Y. as opposed to an on-site study. This required
periodic trucking of wastewater from Southtowns to Tonawanda. The raw feed
was stored for up to three days at ambient temperatures before being fed to
the reactor. This resulted in extremely septic conditions which may have
been in part responsible for the effluent suspended solids problems. As with
the other locations, final effluent filtration will be required to achieve a
10/10 (BODs/suspended solids) standard. At an effluent suspended solids
level of 10 mg/1 an effluent total phosphorus level of less than 0.5 mg P/l
is anticipated for the full scale Southtowns effluent.
The study at Brockton, Mass, utilized larger equipment than the other
studies and, as a result, was less subject to sampling and operational prob-
lems. The Brockton data shows that, at effluent suspended solids levels
typical of activated sludge systems, effluent phosphorus levels below 1 mg P/l
are achievable without filtration. The low temperature data of the Brockton
study and the high temperature data of the Adrian study indicated that the
process could perform well over a range of temperatures.
The Findlay, Ohio study represents one of the first attempts to run the
process with the contact stabilization or step feed modification of the acti-
vated sludge process. After a large amount of background data was obtained
to quantify the interactions between this type of activated sludge process and
the PhoStrip processes, the operating data presented in Table 4 were obtained.
10
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TABLE 4. RESULTS OF PILOT SCALE DEMONSTRATION PROGRAMS
Type of Activated Sludge Pilot Unit
Type of Elut riant
Type of Influent
Duration of Phase, days
Feed Rate (Q) , 1/s
Recycle Rate, % of Q
Stripper Feed Rate, % of Q
Stripper Return to Aeration, % of Q
Stripper Supernatant, % of 0
Elutrlatlon Rate, % of Q
Influent Characteristics, mg/1:
BOD5 (COD)
Total Phosphorus >
Total Suspended Solids
Temperature (Aeration), *C
Total Suspended Solids (Mixed Liquor),
F/M (BODs/dayAg MLVSS)
Effluent Characteristics, mg/1:
BOD5 (COD)
Total Effluent Suspended Solids
Total Phosphorus
Ortho Phosphorus
Texas City, TX
conventional air
primary effluent
municipal
14
.011
14
14
12
17
15
73
7.9
69
22.7
mg/1 1,672
0.4
29
25
0:7
0.3
Adrian, MI
conventional air
primary effluent
municipal
31
.009
20
17
15
17
15
61
8.4
74
26.7
2,244
0.3
16
35
1.6
0.2
Location
Southtowns, N.Y. Brockton, MA
conventional air
primary effluent
municipal
19
.0083
17
7
7
1.3
1.3
121
3.0
89
18.9
2,980
0.4
34
51
1.4
<0.1
conventional air
primary stripper supernatant
municipal
26
.24
37
20
18
14
12
212
11.3
344
12.2
2,525
0.5
11
15
0.8
0.3
Findlay, OH
step feed
final effluent
municipal
12
.0073
30
22
20
20
20
(315)
6.9
62
13.0
2,000
0.6 (COD basis)
(45)
11
0.7
0.1
-------
OBJECTIVES OF PROGRAM
The purpose of the program at Reno/Sparks, Nevada was to demon-
strate the performance of the PhoStrip process on a full scale system and
establish overall process design relationships for the system. Pilot scale
information was to be used to establish the performance characteristics of a
system designed specifically to incorporate the process as opposed to a sys-
tem utilizing existing unmodified tankage. A comparison between the pilot
and full scale system was designed to establish the importance of designing
the activated sludge and PhoStrip systems to complement each other. Inform-
ation on lime requirements, sludge production rates, sludge dewatering
Characteristics and aerobic and anaerobic sludge digestion was also to be
determined.
SCOPE OF PROGRAM
The original scope of the project was to test the process on 50,100
m3/d (13 mgd) and 76,000 m3/d (20 mgd). These data were to be compared to
the results previously obtained at 25,000 m3/d (6 mgd) and information
generated via pilot scale testing. However, the duration of the study was
shortened due to an unforeseen U.S. EPA Region IX one-year-long water
quality study on the Truckee River, which is the discharge point for the ef-
fluent from the Reno/Sparks treatment plant. The study required that all in-
puts to the river be characteristic of standard operation, thus precluding any
test work.
Before the water quality study started, a two-month operational
period at winter operating conditions generated enough data to evaluate the
50,100 m3/d (13 mgd) case and establish significant relationships for the
design and control of the process. The 76,000 m3/d (20 mgd) case was never
tested. Chemical sludge production, lime requirements, and sludge dewater-
ing characteristics were obtained via pilot scale operation.
The proposed studies on the aerobic and anaerobic digestion of the
combined sludges were not completed due to the termination of the test
program.
12
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SECTION 2
CONCLUSIONS
The PhoStrip system has demonstrated the capability of reducing
effluent total phosphorus concentrations to less than 1 mg/1 on both the pilot
and full scale systems tested at Reno/Sparks, Nevada.
The phosphorus removal was achieved through the ability of activated
sludge to take up and release phosphorus as a function of being cycled through
aerobic and anoxic zones. The activated sludge from the PhoStrip system
generally contains a higher phosphorus content than sludge from conventional
activated sludge systems and, thus, is capable of removing more phosphorus
with the waste biomass. The anoxic tank produces conditions which cause
the activated sludge to release phosphorus into a small side stream. The
phosphorus from this side stream can be economically precipitated with lime.
To achieve low effluent phosphorus levels, it is necessary to achieve
both a low filtered effluent phosphorus level and a low particulate effluent
phosphorus content. The effect of particulate matter on effluent phosphorus
concentrations can be controlled by controlling effluent suspended solids
levels and/or phosphorus concentration in the suspended solids.
The control of effluent suspended solids levels below that normally
obtained by activated sludge systems can be achieved through filtration. The
control of the phosphorus content in the suspended solids and the control of
the effluent filtered phosphorus concentration is highly dependent on the
amount of phosphorus that is released in the stripper and the ability to separate
the released phosphorus from the sludge in the stripper tank. The amount of
phosphorus released depends on the operating conditions in the stripper rela-
tive to those in the aeration basin. The ability to separate phosphorus from
the sludge depends on the method employed. Both the sludge recycle and the
elutriation systems utilized in this program proved to be viable methods of
achieving the required phosphorus/sludge separation. The elutriation method
gives the designer more flexibility and the ability to design the process with
minimal stripper tank volume requirements.
The amount of lime required for the process depends on the quantity of
stripper supernatant (usually between 5 and 15% of the influent flow) and the
pH of precipitation. A pH of approximately 9.0 is sufficient to precipitate
13
-------
most of the phosphorus from the supernatant. Utilizing this pH results in the
production of relatively small quantities of sludge which is high in phosphorus
content. This chemical sludge appears to be ideally suited as a high phos-
phate fertilizer.
Economic evaluations of the process indicate that it is a highly cost
effective alternative to phosphorus removal by mineral addition.
14
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SECTION 3
RECOMMENDATIONS
A by-product of the PhoStrip system is a high phosphorus containing
calcium carbonate type sludge which has potential value as a fertilizer.
Studies should be undertaken to determine the characteristics of this sludge
with respect to its applicability to farm land.
The PhoStrip system represents one aspect of a multifaceted sewage
treatment plant. The incorporation of this process into the overall wastewater
treatment plant should be explored utilizing a systems approach.
15
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SECTION 4
PROCESS THEORY
BIOCHEMICAL MECHANISMS
The performance of the PhoStrip process is based on the formation and
elimination of intracellular polyphosphate granules (volutin). This phenome-
non of polyphosphate formation and decay is induced through the continuous
cycling of activated sludge through aerobic and anoxic conditions. As a con-
sequence of the aerobic environment, the conditioned microorganisms remove
phosphate from solution and produce the storage product, volutin. These
organisms then release phosphate into solution while under a condition of
stress (anoxic surroundings). The precise biochemical pathways of this phe-
nomenon have not yet been delineated. However, the hypotheses that follow
have been developed based on work performed on bacteria isolations (17) and
the response of the process to stimuli (temperature, substrates, etc.).
Funs and Chen (17) isolated organisms capable of excessive phos-
phorus, uptake from PhoStrip systems operating at Baltimore, Md. and Seneca
Falls, N.Y. Of these isolates, the organisms of the genus Acinetobacter
most vigorously demonstrated rapid uptake of phosphorus under aerobic con-
ditions and rapid reduction in the size of polyphosphate granules while anoxic.
Russ (18) isolated an organism which he named Acinetobacter phosphadevorus
from the Rilling Road Sewage Treatment Plant, San Antonio, Texas. This
organism showed the same phosphorus storage potential as those isolated from
the PhoStrip systems. It is significant to note that these organisms are obli-
gate aerobes which effectively compete with the facultative species in a sys-
tem with prolonged anoxic periods. It is hypothesized that the formation of
the volutin granules during the aerobic portion of the PhoStrip process is
largely responsible for this ability to compete.
Investigations into the purpose of polyphosphate formation have indi-
cated the following functions for this storage product. (19) First, polyphos-
phate may be used as a phosphate reserve. This hypothesis would suggest
that the major purpose of poly phosphates is to supply phosphorus for metabo-
lism during periods of phosphate starvation. In situations where phosphorus
is stored as a result of undergoing periods of phosphorus starvation, this may
be the case. However, there is no period during which the organisms are
16
-------
starved of soluble phosphorus in the PhoStrip process and, therefore, no need
to store phosphorus according to the rationale of this hypothesis. The second
major speculation about the function of polyphosphate contends that polyphos-
phate is important for the regulation of the phosphorus economy of the cell. It
is important to maintain the inorganic phosphate (Pi) level of the cell below a
certain level to insure efficient energy usage and permit other metabolic re-
actions to occur. This hypothesis may indeed explain why polyphosphate is
stored under aerobic conditions but it yields no clue as to why it is released
during anoxic periods. To explain phosphorus release as a result of the
"Pasteur effect" is inconsistent with the observation that obligate aerobes
(genus Acinetobacter) release phosphorus without undergoing fermentation re-
actions. The explanation that phosphatase enzymes may be responsible for
polyphosphate reduction may eventually satisfy the shortcomings of this hypo-
thesis. However, no linkage has yet been developed to explain why the
presence of facultative bacteria is necessary for the obligate aerobes to re-
lease significant quantities of phosphorus. (17)
The third suggested use of polyphosphate is as an energy source,
either as a "phosphagen" (20-21) or through direct substitution for adenosine
triphosphate (ATP) (22) in energy requiring reactions. A broad definition of a
phosphagen is a naturally-occurring compound which stores phosphate bond
energy and from which phosphoryl groups can be transferred to adenosine di-
phosphate (ADP) to produce ATP.
In an anoxic environment the energy source hypothesis would predict
that obligate aerobes would utilize energy stored in poly phosphates to continue
some of the metabolic functions of the cell. Equation (2) presents an example
of a possible use of energy to produce the Krebs Cycle precursor, acetyl Co-
enzyme A, from acetate. The acetate necessary to drive this
acetate + ATP —> acetyl Coenzyme A + ADP + Pi (2)
reaction to completion is produced by the facultative bacteria while under the
anoxic conditions of the stripper tank. Experiments performed at Union Car-
bide's Tonawanda labs (23) and Penn State University where acetates were
added to sludges obtained from PhoStrip systems have indicated enhanced phos-
phorus release while the addition of glucose was significantly less effective
at increasing the rate of phosphorus release from the cells. The importance of
acetate formation is enhanced by the fact that the organisms of the genus
Acinetobacter prefer acetates as a substrate and will not metabolize glucose.
Since the Krebs cycle cannot function without either molecular oxygen or ni-
trate as the final electron acceptor, the acetyl Coenzyme A content of the cell
increases while the ratio of ATP to ADP decreases. ATP may also be used as
the energy source for the formation of other carbonaceous storage products.
The low ratio of ATP to ADP will cause the polyphosphokinase enzyme (20) to
17
-------
utilize the bond energy and the phosphoryl group stored In the poly phosphate
to produce ATP from ADP. Equation (3) is reversible, and the net direction of
the reaction is dependent on the relative concentrations of ATP and ADP. This
reaction is slow relative to the ATP utilizing reactions; therefore, no ATP
buildup is possible during the anoxic period. Alternately, when the ATP level
of the
ADP + PPn ^± ATP + PPn_i (3)
where PPn = poly phosphate
cell is diminished as in reaction (2), it is possible that short chain polyphos-
phates replace ATP as shown in equation (4). (21) Either of
acetate + PPn 5^ acetyl Coenzyme A + PPn-i + Pi (4)
these reactions may be predominantly responsible for the polyphosphate reduc-
tion observed (17,24) in PhoStrip sludges held under anoxic conditions. In-
vestigators at Penn State University have also established a significant re-
duction in ATP levels in sludges leaving the anoxic PhoStrip stripper tank. (24)
According to this hypothesis, the sludge leaving the stripper tank may
be characterized by the following conditions:
1. low ATP/ADP ratio,
2. high concentrations of acetyl Coenzyme A and/or other carbona-
ceous storage products,
3. relatively low polyphosphate levels in the sludge.
The effect of the anoxic period on the polyphosphate level in the
sludge is shown in Figure 5, These photomicrographs are sludge samples
which were stained to highlight the volutin granules within the bacteria. The
results of this test show that the sludge entering the stripper contained many
large clusters of polyphosphate containing organisms while the same sludge
shows a significant reduction in the size and quantity of the polyphosphate
granules after only an 8-hour anoxic period.
Upon return to the aerobic basin of the PhoStrip system, the organisms
rapidly produce ATP because the reaction rates in the Krebs cycle are enhanced
by the low ATP/ADP ratio and the high concentration of the storage products.
After a short period of time, these reactions increase the ATP/ADP ratio, thus
driving the reaction in equation (3) from right to left. According to this
18
-------
Before entering the stripper
After leaving the stripper
Figure 5. Sludge polyphosphate granules before and
after anoxic period in stripper tank (dark areas are
clusters of polyphosphate containing bacteria.
-------
mechanism, the uptake rate of phosphorus in the aeration basin should be zero
order with respect to phosphorus concentration in solution. Experiments per-
formed at Union Carbide indicate zero order uptake rate at phosphorus levels
greater than 0.5 mg ortho phosphorus/liter of solution. (25)
Consistent with the above hypothesis, early testing performed by Bio-
spherics, Inc. (26) and later studies (27) have indicated that phosphate re-
lease is inhibited in the stripper tank by low levels of nitrate and dissolved
oxygen. The presence of nitrate and oxygen stimulates the ATP producing
reactions of the Krebs cycle.
The major argument against the phosphagen mechanism results from
work by Harold (28) on fungi. He was not able to see poly phosphate break-
down when energy generation was limited or ATP generation from the poly-
phosphate. However, the system that he studied was not consistent with that
responsible for phosphorus removal in the PhoStrip system. Polyphosphate
granules produced via the over-plus phenomenon (phosphate starvation) and
growth-inhibiting situations (acidity, sulfur starvation) may serve different
functions than the poly phosphate produced by the organisms in the PhoStrip
process.
PHOSPHORUS MASS BALANCE CONSIDERATIONS
Figure 6 presents a phosphorus mass balance around a theoretical
PhoStrip system. As shown in this figure, there are three outlet locations for
the influent phosphorus: the final effluent, the waste activated sludge, and
the waste chemical sludge. Ideally, all the removal of phosphorus would be
with the waste activated sludge since this would result in no chemical re-
quirements for the process. In certain instances this has been achieved with
the PhoStrip process and can be used for the design of some full scale systems.
However, with the amount of sludge wasting expected in the theoretical case
of Figure 6, 342 kg/day of phosphorus would have to be present with the vola-
tile suspended solids of the waste activated sludge. This represents more than
16% by weight of the waste volatile suspended solids. The maximum observed
in PhoStrip systems has been only 8%. Even if 8% phosphorus levels were
utilized for design purposes, the effluent quality of the process would be
limited by the effluent volatile suspended solids (EVSS) concentration. At
0.08 P/VSS, the phosphorus in the effluent due to 23 mg EVSS/1 would be
about 1.8 mg/1. To achieve an effluent phosphorus level of less than 1.0
mg/1, EVSS levels near 10 mg/1 would be required. In most cases, effluent
filtration would be necessary to maintain such low suspended solids levels.
The goal of complete phosphorus removal via activated sludge wasting is more
readily achievable on systems with higher sludge wasting rates and/or lower
influent total phosphorus levels than shown in Figure 6.
The use of lime to insolubilize phosphorus permits the PhoStrip process
20
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INFLUENT
FR 38,000 (3.8 x jo?)
TP 10.0 (380)
TSS 100 &800)
VSS65 (2470)
EFFLUENT
FR 38000 (3.8x |O7)
TP 1.0 (38)
TSS 30 (114)
VSS 23 (874)
AERATION
SECONDARY
CLARIFIER
REACTOR
CLARIFIER
/LIME
f
> WASTE
ACTIVATED
SLUDGE-
FR 260(2.6X|05)
TP 230 (62)
TSS 10,000(2,600)
VSS 7,700(2,000)
STRIPPER
WASTE CHEMICAL SLUDGE
FR 23 (2.3XIQ4)
TP 12,000 (280)
TSS 100,000(2300)
VSS 6,000 (1400)
LEGEND
FR FLOW RATE
TP TOTAL PHOSPHORUS
TSS TOTAL SUSPENDED SOLIDS
VSS VOLATILE SUSPENDED SOLIDS
(kg/d)
mg/l (kg/d)
mg/l (kg/d)
mf/\ (kg/d)
Figure 6. Phosphorus mass balance - 38,000 m3d (10 mgd) plant size,
21
-------
to be designed at any P/VSS ratio between 0.03 and 0.08 in the sludge from
the secondary clarifier. At the P/VSS ratio employed in Figure 6 (0.03), efflu-
ent phosphorus levels of less than 1.0 mg/1 can be achieved without post
filtration.
The phosphorus balance presented in Figure 7 represents conditions
expected in streams entering and leaving the stripper tank for the theoretical
situation developed in Figure 6. Evaluation of this information indicates that
only a 0.007 differential in the P/VSS ratio of the sludge entering and leaving
the stripper is required to achieve efficient performance. The P/VSS level in
the stream entering the stripper drops from 0.030 to 0.023 in the stream re-
turned to aeration. A given level of P/VSS reduction requires a minimum mass
flow of VSS through the stripper so that mass balances are satisfied. Utilizing
a small differential in the P/VSS levels in the sludge permits the use of short
anoxic periods in the stripper tank.
Since phosphorus is continuously released while the sludge is in the
stripper tank, a portion of this solubilized material is recycled to the aeration
basin with the return flow. Elutriation efficiency is a measure of the fraction
of solubilized material that is available for precipitation as well as the frac-
tion that is returned to the aeration basin. At a 45% elutriation efficiency,
more than half of the solubilized phosphorus returns to the aeration basin to
be taken up by the sludge.
Two methods of maximizing the amount of phosphorus in the superna-
tant have been presented earlier. The sludge recycle method (Figure 2) and
low phosphate elutriation modification (Figure 4) were discussed briefly. The
sludge recycle system tends to make the stripper tank approach a completely
mixed basin when the recycle rate is high. Figure 8 shows the flow schematic
for a stripper tank in the sludge recycle mode as well as the assumptions for a
theoretical mass balance analysis of this mode of operation.
Figure 9 summarizes the results of the mass balance analysis of the
sludge recycle option. High elutriation efficiencies are only achieved at high
recycle fractions and high supernatant flow rates. The results of this analysis
are consistent with pilot scale data obtained on the PhoStrip process. The
elutriation efficiency for the low phosphate containing elutriant was also ob-
tained on a pilot scale. The efficiency of this system is also presented in
Figure 9. At relatively low elutriation rates, the low phosphate elutriation
(LPE) system approaches the performance of the sludge recycle option. As the
elutriation rate increases, the performance of the LPE system improves sub-
stantially over that of the sludge recycle system. In properly designed sys-
tems, the elutriation rate is equal to the stripper supernatant flow. The
effects of these relationships will be established in an example which will be
presented later.
22
-------
SUPERNATANT
FR 5.6X103 (5.6 X|Q6)
TP 55 (308)
TSS
VSS
30
23
(168)
(129)
STRIPPER FEED
FR 5.6 XIO3 (56 X|06)
TP 230 (1288)
TSS 10,000 (5.6 XIO4)
VSS 7,700 (4.3 XIO4)
ELUTRIANT
FR 56 X|Q3 (5.6X|Q6)
TP 5 (28)
TSS 30 (168)
VSS 2 (129)
SLUDGE RETURN TO AERATION
FR 5.6XIO3 (56 XIO6)
TP 180 (1008)
TSS 10,000 (5.6 x|04)
VSS 7700 (4.3XI04)
LEGEND
FR FLOW RATE m3/^ (kg/d)
TP TOTAL PHOSPHORUS mg/l (kg/d)
TSS TOTAL SUSPENDED SOLIDS mg/l (kg/d)
VSS VOLATILE SUSPENDED SOLIDS mg/l (kg/d)
Figure 7. Mass balance around the stripper tank.
23
-------
S; STRIPPER
SUPERNATANT
R,;STRIPPER
1 FEED
Ro', INTERNAL
SLUDGE
RECIRCULATION
R3; SLUDGE RETURN TO AERATION (STRIPPER UNDERFLOW)
ASSUMPTIONS;
I. NO INHIBITION OF PHOSPHORUS RELEASE DUE TO PRESENCE
OF NITRATES OR DISSOLVED OXYGEN IN R|.
2. R, AND R2 ARE COMPLETELY MIXED.
3. THE SOLUBLE PHOSPHORUS CONCENTRATION IN R, IS
NEGLIGIBLE.
Figures. Stripper tank mass balance, sludge recycle modification.
24
-------
0.8_
Q
Ul
uj0.7_
LU
QC
O)
gO.6.
O
2 09
y o.s
u_
p0.4_
Ul Q-
O)
ID
(X
O
X
o.
).2_
).!_
F =
SLUDGE RECYCLE FLOW
STRIPPER FEED FLOW
LOW PHOSPHATE /
ELUTR1ATION /
SYSTEM
F=0.25
° 0.2 0.4 05 0.8 1.0 1.2 1.4 1.6 1.8 2.0 22 2.4 2jS 2.8
SUPERNATANT FLOW/STRIPPER UNDERFLOW
(OR ELUTRIATION FLOW)/ TO AERATION
Figure 9. Elutriation efficiency for the sludge recycle and elutriation
systems.
25
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SOLIDS FLUX THEORY IN RELATION TO STRIPPER DESIGN
The theoretical evaluation of final settling tank behavior with respect
to thickening has been performed by Dick. (29) Generally, the total flux of
suspended solids in a settling tank or thickener (GT) can be summarized as
the sum of the flux due to gravity settling (Gg) plus that due to the downward
bulk velocity as a consequence of the withdrawal of solids from the bottom of
the clarifier (Gu) . Equation (5) presents a mathematical description of the
total flux as a function of suspended solids concentration at the point of in-
terest, GI, the settling velocity at that concentration, vj., and the bulk
velocity, u.
+ cu (5)
Figure 10 graphically illustrates the addition of the two types of flux curves to
produce the total flux. With reference to Figure 10, if the suspended solids
concentration of a stream entering the settling tank, co, is greater than Cm/
and the desired underflow concentration is cu, then the sludge in the settling
tank may exist at all concentrations between cm and cu. However, one con-
centration, CT , exhibits the minimum solids flux called the limiting flux, G^.
For a given surface area G-^ depends only on the settling characteristics of
the sludge and the underflow rate. For proper steady state thickening perform-
ance, the solids loading per unit area, G^, must equal the limiting flux.
In designing a stripper tank for the PhoStrip process, the above re-
quirement provides the means for determining the cross -sectional area neces-
sary to obtain a given underflow concentration, cu. Referring to Figure 8,
equation (6) predicts the area required to give the desired underflow
C1R1 + C2R2
A = (6)
GI = suspended solids concentration in stream R±
C2 = suspended solids concentration in stream R£
concentration for the sludge recycle system. As was presented earlier, there
is a minimum mass of sludge, CiR]_, which must enter the stripper tank to
satisfy mass balance requirements for phosphorus release. Mass balances
also dictate a relationship between supernatant volume and recirculation rates
(Figure 9) necessary to achieve high elutriation efficiency. The limiting flux
in equation (6) is defined in equation (7). Therefore, once Rj is defined
26
-------
to
CnC0 Q. C2
Figure 10. Components of total flux settling tanks.
-------
GL = CLVL + CL -1^— (7)
CL = limiting flux suspended solids concentration
VL = limiting flux settling velocity
from the suspended solids level in the sludge from the secondary clarifier and
mass balance considerations, the cross-sectional area of the stripper depends
only on the settling characteristics of the sludge and the tradeoff made be-
tween the stripper supernatant flow and the recirculation rate according to
Figure 9. Equation (8) demonstrates this dependence on the recirculation rate
and settling characteristics (VL) . It should be noted that C2 = Cu and since
CL is always
C]_RI + c2R2 - CL (RI - s + R2)
A = 7^7, (s)
less than Cu, the cross-sectional area is minimized by reducing R^. However,
with the sludge recycle system, R2 can only change if S is changed. A bal-
ance between the cost of lime for precipitation resulting from changes in S and
the capital cost associated with cross-sectional area must be struck.
For the sake of consistency, it is important that a solids flux analysis
of the secondary clarifier be performed for the proposed operating conditions.
This is necessary because one of the key parameters for designing the area
and volume of the stripper tank is the suspended solids level in the recycle
stream from the secondary clarifier (C^). Dick and Young (30) presented a
mathematical method of determining the performance of secondary clarifiers
from a thickening viewpoint. They utilized the relationship presented in
equation (9) to quantify the effect of suspended solids concentration on set-
tling velocity, Vj. The constants, a and n, were shown to depend on the
physical
vi = acfn (9)
characteristics of the sludge. The effective prediction of settling velocity via
equation (9) is limited to a range of solids concentrations bounded by approxi-
mately 3,000 mg/1 and 30,000 mg/1. This range may vary, depending on the
physical characteristics of the sludge. Dick and Young (29) showed that
utilizing equation (9), the limiting flux could be determined through the appli-
cation of equation (10). For the PhoStrip process
28
-------
(10)
r = the sludge recycle flow divided by the raw feed flow
Q = the raw feed flow
u = R2 + R3 . thus equation (11) results from substitution
£
n-1
r -
GL -
n
can also be defined according to equation (12).
GL =
(11)
(12)
Combining equations (11) and (12) and solving for A, yields equation (13).
A = -r
R2 + R3
(13)
where Co = Cu
Equation (13) is used for determining the cross-sectional area required for a
given set of a and n constants related to the sludge in question. The R2/ R3,
and Co variables are determined from mass balance considerations. For the
LPE modification, equation (13) is applicable with R2 = O.
As an example of the use of equation (13), let the following be
assumed for a sludge recycle system:
1. Plant flow equals 1,578 m3/hr (10 mgd)
2. Minimum flow to stripper 10% of Q at 18,000 mg/1 TSS
29
-------
3. a equals 9.21 x !CT6m/hr (30)
4. b equals 2.26 (30)
5. Elutriation efficiency greater than or equal to 0.50
6. Stripper retention time equals 10 hrs based on R3
From Figure 9, f = 2.0 and the supernatant flow equals 1.5 times the sludge
returned to aeration from the stripper so that E £0.5 may be achieved.
Initially this results in R2 = 20% of Q and S = 6% of Q while R3 = 4% of Q. A
mass balance around the stripper indicates that C3 = 45,000 mg/1. However,
the level of C3 is outside the range of predictability of equation (9). There-
fore, a stripper underflow concentration of 25,000 mg/1 is chosen to include a
safety factor. Since 10% of Q is required to be fed to the stripper at 18,000
mg/1, then from a mass balance R3 must equal .066 Q to achieve the same
throughput. To achieve E 2 0.5 with f = 2.0, S must now become 0.10 Q
(Figure 9). Because Rj = R3 + S and f = 2, Rj becomes 0.166 0 while R2 be-
comes .332 Q.
This set of conditions results in a reduction of the thickening capacity
of the secondary clarifier because the solids flux in the stripper becomes
controlling. Consequently, the blanket level in the secondary clarifier will
become negligible and the underflow from the clarifier will average '-9900mg/L
Under these assumptions, equation (13) predicts a cross-sectional area re-
quirement of 2200 m2 (23, 690 ft2).
If the low phosphate elutriation (LPE) system is employed, R£ = 0 in
equation (8), thus producing the minimum cross-sectional area. Further,
since the supernatant flow is independent of the Rj and R% streams in the LPE
system, any desired level of supernatant flow may be achieved. Therefore,
the cross-sectional area of the stripper and the lime requirements can be
optimized independently for this modification.
For the LPE system, assumptions 1 through 6 are valid. It is also
important that Cj = C3 so that all the supernatant formed in the stripper be a
result of the elutriation and not thickening. (Thickening is to be avoided
because thickening occurs before the phosphorus is released from the sludge
and, as a consequence, the supernatant resulting from thickening contains
very little phosphorus.) Therefore, C3« 18,000 mg/1 and Figure 9 predicts a
10.5% of Q elutriant flow to produce an elutriation efficiency greater than 50%.
This results in 10.5% Q as the supernatant. Applying equation (13) to the LPE
system results in a stripper cross-sectional area requirement of 411 m2
(4430ft3).
30
-------
A comparison between these two options indicates that at approxi-
mately the same stripper supernatant rate - which is equivalent to the same
chemical cost - the LPE modification requires less than 19% of the area of the
sludge recycle system. The stripper volume for the LPE design would be
2079 m3 while the volume of the sludge recycle unit would be 3735 m3. Both
volumes include 1.2 m of free liquid above the sludge blanket in the stripper.
Under other conditions the difference between the two operating modifications
may not be as great, and economical performance using the sludge recircula-
tion mode can be achieved.
DESCRIPTION AND INTERACTION OF VARIABLES AFFECTING THE PROCESS
- The performance of the process is highly dependent on the design of
the stripper tank relative to the design of the activated sludge process. The
interrelationships between the aerobic system and the anoxic sidestream will
be established by reference to Figure 11. To evaluate the ability of the system
to accumulate phosphorus within the biomass, two factors must be considered.
First, the kinetics of the process must be understood, and second, the maxi-
mum capacity of the organisms with respect to phosphorus loading or capacity
must not be approached.
The kinetics of phosphorus uptake has been shown to be zero order
with respect to ortho phosphorus concentration down to very low levels. (25)
The rate of phosphorus uptake is dependent on the general activity of the or-
ganisms in the aeration basin which may be related to food to microorganism
ratio, F/M. Pilot scale testing has verified the importance of the F/M level
to phosphorus uptake rate and has indicated a modest dependence of uptake
kinetics on temperature. Therefore, the variables RTA (based on total flow),
BODs, and MLVSS are important as a result of the F/M relationship. Phos-
phorus removal rate generally increases with increases in F/M. The retention
time and MLVSS parameters are also important to the kinetics of accumulation
for another reason. Since the kinetics are zero order with respect to phosphor-
us, the amount of phosphorus taken up is directly proportional to the retention
time available for uptake and the number of organisms taking up phosphorus
(related to the MLVSS level). The number of organisms in the MLVSS that can
take up phosphorus to form polyphosphate granules in turn depends on the mass
of sludge entering and leaving the stripper tank. The number of organisms in
the aeration tank possessing this uptake capability increases with increased
sludge flow through the stripper. Thus, the PhoStrip process can be designed
to take up any normal level of influent phosphorus by proper adjustment of the
stripper mass throughput relative to RTA. This adjustment will vary according
to the quantity of phosphorus to be removed. Like other biochemical processes
the kinetics of phosphorus removal can be related to temperature via an
Arrhenius expression. Generally, the rate of removal increases with increas-
ing temperature.
31
-------
AEROBIC
TOTAL (ACCUMULATION ZONE)
PHOSPHORUS, Psol.
BODC
s
Psol.
RETENTION TIME=RTA'
MLVSS
TEMPERATURE
Psol.,P/VSS,C3iR3
BOD5
TOTAL
PHOSPHORUS
A A
ANOXIC
(REMOVAL ZONE)
V
WASTE
CHEMICAL
SLUDGE
PSO|.,PXVSS,R31C3
P/VSS R,C
WASTE
BIOLOGICAL
SLUDGE
RETENTION TIME = RTC
VSS
TEMPERATURE
*BASED ON
Figure 11. Variables affecting performance of the PhoStrip process.
32
-------
From Figure 11 it can be seen that there are three sources of soluble
phosphorus entering the aeration tank: that with the raw feed, that solubilized
in the stripper but not appearing in the supernatant, and the phosphorus not
precipitated via lime addition. The first factor is uncontrollable and may rep-
resent as much as 90% of the phosphorus to be taken up in the aeration basin.
It is important to note that much of the non-soluble phosphorus in the influent
is hydrolyzed by the activated sludge process and thus becomes soluble. The
second factor, Psoi, of stream R$ depends on the elutriation efficiency of the
process. At low efficiencies, it is possible that more than 50% of the phos-
phorus entering the aeration basin may be solubilized from the polyphosphate
granules. The last stream, the residual from lime precipitation, can be easily
controlled so that it represents less than 5% of the influent to the aeration
basin. Therefore, this stream may be ignored with respect to its contribution
to phosphorus in the aeration basin.
The second major factor to be evaluated when considering the aerobic
portion is that the ratio of the phosphorus level in the sludge to the phosphorus
saturation level is dependent on many of the same parameters as the kinetics.
The F/M in the aeration basin and mass flow through the stripper increase the
ultimate capacity of the sludge for phosphorus by increasing the number of or-
ganisms with the potential of storing phosphorus. The F/M contributes to this
increase by increasing the growth rate of the organisms. An increase in the
mass flow through the stripper increases the capacity by stimulating more or-
ganisms to the metabolic pattern of phosphorus storage. The effect of F/M
becomes apparent as an increase in the oxygenliptake rate of the sludge under
aeration and as an increase in sludge wasting. The effect of mass flow through
the stripper on phosphorus saturation level is not obvious. This latter fact is
due to the effect of stripper performance on the P/VSS level of the sludge.
As in the evaluation of the aerobic zone, the performance of the anoxic
zone with respect to phosphorus release depends on kinetics and the ratio of
P/VSS in the sludge to the sludge's saturation level. Earlier studies (23) have
indicated that the rate of phosphate release is dependent on the acetate level
of the anoxic solution. This is consistent with Fuhs and Chen (17) who stated
that a product was being produced by organisms not responsible for phosphorus
uptake that facilitates release in the anoxic zone. The facultative organisms
produce acetates and Krebs cycle intermediates during the anoxic period. The
rate of formation of these compounds controls the rate of phosphorus release.
Therefore, the length of time that a given mass of sludge is held in the strip-
per tank (RTg) will affect the amount of acetate formed and thus phosphorus
released. The rate of acetate formation per mass of sludge is also dependent
on the overall activity of the sludge. An activated sludge operating at a high
F/M will produce acetates more rapidly than a system at low F/M levels.
Temperature also affects the rate of acetate formation which causes the re-
lease kinetics to exhibit an Arrhenius-type temperature relationship. Thus,
the phosphorus level in the sludge leaving the stripper and entering the
33
-------
aeration basin can be controlled by the retention time in the stripper.
To optimize stripper performance, it is desirable to maximize phos-
phorus release per unit volume of stripper tank. This is accomplished by
maintaining high suspended solids levels in the anoxic zone and optimizing
the stripper sludge retention time. At very short retention times only small
amounts of phosphorus are released from each unit mass of sludge put through
the stripper. In order to solubilize enough phosphorus to achieve a low ef-
fluent phosphorus concentration, high stripper feed rates are required. There-
fore, the size of the stripper tank must increase to handle the higher mass
throughput rates. This mode of operation may increase the P/VSS level
throughout the system depending on what fraction of the phosphorus removed
ends up in the stripper supernatant (elutriation efficiency). High P/VSS levels
could result in phosphate effluent quality problems due to the phosphorus con-
tent of the effluent volatile suspended solids.
On the other hand, the use of long anoxic periods with small sludge
flow rates does not necessarily minimize stripper volume either. In order to
utilize a low volume of sludge throughput, the sludge must contain large
quantities of polyphosphate. From a microscopic view, the individual organ-
isms entering the stripper will contain different levels of polyphosphate. Some
organisms will have small concentrations of polyphosphates. When this level
of polyphosphate is utilized, the organism can no longer release phosphorus,
thus the rate of phosphorus release per unit mass of sludge decreases.
Therefore, the phosphorus release per unit tank volume decreases. In order
that sufficient phosphorus is released to achieve low soluble effluent phos-
phorus levels, a high P/VSS ratio must be attained in the aeration basin.
However, long anoxic periods generally result in a small number of organisms
with high individual phosphorus levels but low phosphorus levels on a P/VSS
basis. Therefore, this procedure will also require high mass throughputs to
achieve the overall phosphorus removal required. The flow rates under this
mode will be substantially shorter than the short retention time mode but the
long retention times can also result in high volumes. Also, the high P/VSS
levels required can result in the same effluent quality limitations presented
for the short retention time case.
«
Therefore, to minimize tankage requirements, a balance must be struck
between retention time and mass throughput so that reasonable P/VSS levels
are achieved in the sludge. The optimization of the stripper tank volume is
highly dependent on elutriation efficiency. If a large fraction of the phos-
phorus that is released is washed into the supernatant, less phosphorus per
unit mass needs to be released (mass balance) and the size of the stripper can
be reduced.
At a given stripper size and mass throughput, the elutriation efficiency
can be used to control the P/VSS level of the sludge according to the mass
34
-------
balance discussion presented earlier (Figure 6). The increase in chemical
phosphate sludge mass via an increase in elutriation efficiency results in less
phosphorus available to be removed with the waste activated sludge at the
same sludge wasting rate. Therefore, the sludge will possess a lower P/VSS
level. P/VSS can also be controlled via changes in throughput of sludge and
stripper retention time. However, once the stripper tank is installed, the
flexibility of this method of control is limited by the fixed size of the stripper
tank. With the LPE system, control of the elutriation efficiency and thus
P/VSS ratio is easily achieved by changing the elutriation rate while with the
sludge recycle mode elutriation efficiency control is most easily achieved by
controlling the stripper supernatant flow rate. This is accomplished by vary-
ing the stripper feed and sludge return rates.
Because of the effect of temperature on the kinetics of phosphate re-
lease the optimum retention time in the stripper tank will be influenced by the
temperature of the wastewater.
35
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SECTION 5
DESCRIPTION OF FACILITIES
MOBILE PILOT PLANT
The Union Carbide Mobile PhoStrip pilot plant was used to demonstrate
the performance of a system designed to optimize the LPE system. Figure 12
is a schematic diagram of the mobile pilot plant which integrates a coarse
bubble, diffused air activated sludge system with the PhoStrip phosphorus re-
moval system. The nominal feed rate to the van is 0.11 m3/hr. Although it is
designed to optimize the performance of the LPE mode of operation, it is also
capable of operating in the sludge recycle and stripper supernatant recycle
modes of operation. However, the geometry of the tanks is such that less than
optimum performance would be expected in the latter two modifications.
The basic components of the pilot plant as illustrated in Figure 12 are
as follows:
1. Air Reactor: (Size: 2.44mx2.13mxl.37m) The air reactor is
constructed from stainless steel. It has removable baffles, an adjustable
weir, and quick-connect couplings so that feed and recycle streams may be
introduced at any desired location. Diffused air provides the mixing and mass
transfer through Dravo leaf spring diffusers. The reactor has the capability of
being operated as a completely mixed system, a conventional activated sludge
system, and a step feed or contact stabilization unit.
Two Dravo diffusers are situated in each of the three passes of the
serpentine type conventional activated sludge system. The compressed air is
provided by six Model 4907 Thomas compressors.
2. Secondary Clartfier: (Size: 1.22 m diameter x 1.37 m side wall
depth) The secondary clarifier is a center feed, peripheral overflow type with
plow-type scrapers. The sludge is removed through a discharge line at the
center of a conical bottom. Part of the sludge can be pumped to the stripper
tank while the remainder may be returned directly to the aeration basin.
3. Stripper Tank: (Size: 1.12 m diameter x 1.83 m side wall depth)
The stripper tank is a standard gravity-type thickener with center feed,
36
-------
VENT
STRIPPER
A
oo
LIME
I MIX
ILIMEJ
SLURRY
c
L
A
R
I
F
I
K
T
SECONDARY
CLARIFIER
V V
DRAIN
t
^ELUTRIATION (INFLUENT)
AERATION
A
I
I
I
A
I
INF
COMPRESSED
AIR
STRIPPER FEED
STRIPRER SLUDGE RETURN
SECONDARY SLUDGE RETURN
SLUDGE RECYLE OPTION
Figure 12. Schematic Diagram - PhoStrip Pilot Plant, Reno/Sparks, Nevada,
-------
peripheral overflow and center sludge withdrawal. No rakes were added to in-
duce thickening. A distribution arm for use with the LPE and stripper super-
natant recycle systems is located at the bottom of the tank. The arm is feed
liquid from a pump through a rotating unit at the top of the tank. The sludge
recycle mode utilizes a pump to remove sludge from the bottom of the stripper
and return it to the top of the tank through the stripper feed line. A second
sludge pump is used to return sludge from the bottom of the stripper to the
aeration basin.
4. Lime Mix Tank: (Size: 0.61 m diameter x 0.91 m deep) The lime
mix tank receives phosphorus-rich supernatant liquid from the stripper over-
flow and lime slurry from the lime slurry tank. Both are thoroughly mixed by a
mixer mounted on top. Any desired pH above that of the stripper supernatant
and below that of the lime slurry (pH"12.5) may be achieved.
5. Lime Slurry Tank: (Size: 0.61 m diameter x 0.91 m deep) The lime
slurry tank contains the lime which is pumped to the mix tank.
6- Clarifier: (Size: 0 .46 m diameter x 1.37 m depth) This clarifier
receives the overflow from the lime mix tank. The clarified liquid is either
pumped back to the aeration basin or it may be used as an elutriant in the LPE
system. The phosphate containing chemical sludge underflow is pumped to
the drain.
RENO/SPARKS WATER POLLUTION CONTROL PLANT
The Reno/Sparks Water Pollution Control Plant is a jointly-owned
facility serving the cities of Reno and Sparks, Nevada. The plant is designed
for an average flow of 76,000 mVd (20 mgd) and discharges into the Truckee
River. A simplified flow schematic of the facility is presented in Figure 13.
The pump station collects the wastewater from the two municipalities and
feeds the treatment plant through variable speed controlled pumps. The waste-
water passes through an aerated grit chamber to the primary and secondary
treatment systems which are modularized. There are three modules, each con-
sisting of a primary clarifier, an aeration basin, and a final clarifier. The
capacity of each module is 25,000 m3/d (6.67 mgd).
The primary clarifiers are square units 25.6 m across by 3.3 m side
water depth. These are center feed units with peripheral overflow. Plow-type
scrapers on a modified mechanism similar to that used in circular clarifiers
were utilized to transfer the sludge from the floor of the clarifiers to a central
withdrawal well.
The aeration basins are diffused air units with coarse bubble diffusers.
Each modular aeration basin employs a three-pass serpentine design, each
pass having the approximate dimensions 54.9mx8.2mx5.3m side wall
38
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RAW WASTEWATER
ANAEROBIC DIGESTJON
co
DIGESTED SLUDGE TO SAND
BED AND LAND FILL
I
P
P
R
1
PUMP V J V J
STATION X^Nv^-^ X^"^
AER^
GRIT
CHAJ
C •*
L
A
M 1
A F ^
R
Y
1 ^
E
R
S
Ss.
1 ^
MED
^BER
1
v y
f3^
/
WASTE
FROM
.
>
X
r ^
SLUDGE I )
PRIMARY ^ — /
AERATION 1
^v 'N
\
AERATION 2
/^ r|\
V
AERATION 3
/fi i\
FINAL
CLARIFIERS
X
9
^^
^
^J
10
^J
1®
u
— ^
CHLi
V
^
TO
TRUCKEE
RIVER
T
ORINATION
=f
A
E
P R
0 A
S T
T 1
0
N
WASTE SLUDGE TO PUMP STATION
Figure 13. General flow schematic - Reno/Sparks Water Pollution Control Plant.
-------
depth. The plant has the capability of adjusting the aeration rate to corres-
pond to the oxygen demand at various locations.
The secondary clarifiers are square tanks 25.6 m across and 3.3m
side water depth. The secondary clarifiers use rapid sludge return (RSR)
siphon units to pick up sludge for return to the aeration tank. As was the case
in the primary system, the sludge transfer unit was the type normally employed
in circular clarifiers with modifications to accommodate use in square tanks.
The sludge pickup units deposit sludge in a wet well from which it is pumped
to the aeration basin. The return sludge pumps are variable speed and dis-
charge at two points in the aeration basin, one at the head end and one mid-
way through the first pass of each module. Venturi meters are used to mea-
sure return sludge flow rates.
The effluent from the secondary clarifier flows to a post aeration basin
to increase the dissolved oxygen concentration to a level above that required
for water in the Truckee River (D.O. > 6.0 mg/1). Following post aeration the
effluent is chlorinated and then discharged.
The waste sludge from the aeration basins flows by gravity to the
wet well of the raw sewage pump station. This material settles out in the
primary clarifier along with the primary solids. The combined primary plus
secondary sludge is periodically pumped from the primary clarifiers to a two-
stage anaerobic digestion process. The digested sludge is dewatered on sand
beds and trucked to a land fill.
MODIFICATIONS OF THE FULL SCALE PLANT
The Reno/Sparks Joint Water Pollution Control Plant was modified
twice for evaluations of the PhoStrip process. The first modification was
initiated by Kennedy Engineers, 657 Howard Street, San Francisco, California
94105, to test the general performance of the process utilizing the sludge
recycle option. (31) After testing on the sludge recycle mode was completed,
the flow configuration of the process was changed to that of the LPE system.
During both of the test periods, the primary clarifier labelled #1 in
Figure 13 was utilized as the stripper tank; and, as a result, Primaries #2 and
#3 were operated at approximately 150% of design load because the flow to the
plant was near design capacity. The effluent from these two primary clarifiers
was equally distributed to the three aeration basins.
SLUDGE RECYCLE MODIFICATION
During this phase of operation, the secondary aeration basin labelled
#1 was used to assess the performance of the PhoStrip system. Thus, 1/3 of
the total plant flow (25,000 m3/d) was treated via the PhoStrip process.
40
-------
Aeration basins #2 and #3 were used as controls to determine comparative re-
moval efficiencies for conventional activated sludge systems. In order to
achieve this condition, primary clarifier #1 and aeration basin #1 were modi-
fied according to Figure 14. The return sludge piping was extended from the
head end of the aeration basin to the distribution unit near the center of the
stripper tank. The 406 mm valves in the return sludge line were used to
manipulate the flow to the stripper tank and aeration basins. Because the
variable speed recycle pump control system would not function properly below
a minimum flow rate, the 406 mm valve midway down the first aeration pass
was used to maintain at least this minimum flow from the secondary clarifier.
The distribution device near the center of the stripper consisted of a cylin-
drical tube baffled at the bottom by a cone. The cone imparted some horizon-
tal velocity to the sludge which left the cylinder 1.8m below the surface of
the liquid. A pump was installed to remove the sludge from the bottom of the
stripper tank for return to the aeration basin and to provide the sludge recycle
stream. The output of the pump was calibrated and the relative sludge re-
cycle and return flows were obtained from determinations of relative flow
rates as a function of the settings on the 152 mm valve that discharged to the
aeration basin. The anoxic recycle sludge was pumped to the central distribu-
tion device. The supernatant from the stripper tank was siphoned to a drain-
age ditch where it flowed to a juncture with the chlorinated plant effluent.
The supernatant flow rate was determined from calibrations made previously
on the 152 mm "Ballcentric" type plug valve.
t
LPE SYSTEM MODIFICATION
As was shown in the example presented with the Solids Flux Theory,
the use of the LPE system reduces the cross-sectional area requirement rela-
tive to that of the sludge recycle system. Since the primary clarifier (stripper
tank) at the Reno/Sparks plant had a fixed cross-sectional area, the'solids
flux considerations indicated that two-thirds of the plant flow (50,000 m3/d)
could be treated with the available area. As a result, the system was modi-
fied according to the flow schematic presented in Figure 15. Aeration mod-
ules #1 and t2 were converted to the PhoStrip process. The existing sludge
return pumps were used to pump settled activated sludge to the head end of
each module's aeration basin. At that point, the sludge streams were split.
Some of the sludge was discharged through a 152 mm valve to the aeration
basin while the remainder continued on to the center well of the stripper. No
special inlet device was required during this mode of operation. The relative
flows to-the stripper and aeration basins were obtained from-measurements of
the total recycle flow with the Venturi meters and the stripper feed flows via
magnetic flow meters. The return sludge from the stripper was transferred to
the aeration basin utilizing the same pump as that employed in the sludge re-
cycle system tests. The discharge from the pump was split into two streams
which emptied into the head end of each of the aeration basins. The flow of
these streams was determined through the use of magnetic flow meters.
,j
41
-------
N)
RETURN PUMP
ANOXIC RECYCLE SLUDGE
DISTRIBUTION
DEVICE
(PRIMARY
STRIPPER TANK
plug valve
52 mm
SUPERNATANT TO
DRAINAGE DITCH
r
EFF
X 152mm valve
^ 406mm X valves
1
-------
U)
RETURN SLUDGE
^ _ _
(PRIMARY *i)
STRIPPER TANK
^*~®
±
-x
I
AERATION *|
AERATION *2
AERATION*3
m=flow meter
r
tr
SECONDARY
CLARIFIER*!
SECONDARY
CLARIFIER**2
SECONDARY
CLARIFIER*3
TO POST AERATION
Figure 15. Reno/Sparks Water Pollution Control Plant - PhoStrip system control diagram -
Low phosphate elutriation system .
-------
The elutriant employed during the period of this study was the primary
effluent from primary module #2. This LPE stream was pumped to a distribution
system. The top of the system was a circular basin divided into four concen-
tric rings, each being fed elutriant individually. Each concentric ring fed a
vertical pipe that transferred the elutriant to a horizontal arm. Two of these
arms distributed the elutriant over the inner half of the tank and two arms were
used to cover the outer area. The arms were supported from the truss bridge
at the lowest possible location. The entire distribution system, including
basin and arms, rotated along with the scraper mechanism. The elutriant flow
was measured via a vortex shedding m^ter.
The supernatant from the stripper was pumped to aeration basin #3 so
that no unchlorinated material would enter the Truckee River. The flow rate of
this stream was measured through the use of a second vortex shedding meter.
44
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SECTION 6
RESULTS &.DISCUSSION
PILOT SCALE EVALUATION
The pilot scale program performed at Reno/Sparks, Nevada was divided
into three phases of operation. The first phase employed the sludge recycle
system to produce a stripper supernatant high in soluble phosphorus. The
second and third phases used the LPE modification with primary clarifier efflu-
ent employed as the elutriant. Phases II and III differ in that the stripper
supernatant was not treated during Phase II, while during Phase III the super-
natant was treated with lime and returned to the aeration basin.
The procedure used to evaluate the performance of the pilot plant was
to set up the desired operating conditions on the pilot plant and monitor only a
few basic parameters: flow rates, suspended solids, and ortho phosphates;
until the plant stabilized and achieved steady state operation. Once steady
state was obtained, the system was intensively monitored for a period of from
two to three weeks. Table 5 presents the analytical tests performed during the
periods of intensive evaluation. Samples for analysis of influent, effluent,
and stripper supernatant were 24-hour composite samples. All other samples
were grabbed once each day. All analyses were performed according to U. S.
EPA (32) approved procedures. The process operation monitoring was performed
once each day and included measuring and adjusting all flow rates (influent,
elutriation, stripper influent and underflow, and lime slurry feed); measuring
blanket levels in the secondary clarifier, stripper, and chemical clarifier, and
taking reactor temperature and dissolved oxygen readings. Wasting of sludge.
from the secondary clarifier was performed both manually and automatically.
Wasting of the lime precipitated phosphorus sludge was performed manually to
maintain a constant blanket level in the chemical clarifier.
The pilot plant arrived at the Reno/Sparks Water Pollution Control Plant
on October 15, 1975. The system was seeded with recycle sludge from the
existing full scale plant during the first week of November. Since this was the
first time this pilot plant had ever been operated, several mechanical problems
were encountered which had to be solved during the course of the program.
Following startup and shakedown, an intensive sampling and analytical pro-
gram was performed from November 19, 1975 through December 8, 1975,
45
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TABLE 5 . ANALYTICAL MONITORING OF THE
PHOSTRIP PILOT PLANT, RENO/SPARKS, NEVADA
Parameter
Frequency
Sample Point
1 . COD Total
2 . TSS & VSS
Daily
Daily
Influent
Effluent
Influent
3. Total P
Daily
4. Ortho P
Daily
Effluent
Secondary Clarifier Underflow
Stripper Underflow
Stripper Supernate
Mixed Liquor
Influent
Effluent
Stripper Supernate
Aeration Effluent
Filtered Aeration Effluent
Secondary Clarifier Underflow
Filtered Clarifier Underflow
Stripper Underflow
Filtered Stripper Underflow
Chemical Clarifier Supernatant
Influent
Effluent
Stripper Supernate
46
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Phase I. Primary settled wastewater from the full scale plant was used as feed
for the pilot plant. The supernatant from the stripper was allowed to flow to
drain. As will be discussed later, the final effluent quality from this mode of
operation was not as good as anticipated and the next month was spent trying
to improve the performance of the sludge recycle mode. On January 19, 1976
the pilot plant was switched to operation in the LPE mode with primary clarified
effluent as the elutriant. After mechanical problems were solved and steady
state operation was achieved, the Phase II intensive evaluation began. Phase
II lasted from February 23, 1976 through March 7, 1976. During this period
the supernatant from the chemical clarifler was allowed to go to drain. There-
fore, Phase III was initiated on March 8, 1976 to run the system in such a
manner as to remove phosphorus from the system only through wasting of the
biological or chemical sludges. The period of intensive evaluation lasted from
March 20 through April 2, 1976.
Table 6 contains a summary of the operating conditions maintained dur-
ing the intensive evaluation period of Phase I. The conditions maintained on
the pilot plant are indicative of average operating conditions observed for the
full scale plant. The flow rate and suspended solids data around the stripper
are typical of an air PhoStrip system which produces a supernatant through
thickening. The f parameter is used for a comparison of the actual elutriation
efficiency for this system with the theoretical model presented earlier. The
food to mass ratio (F/M^) presented in Table 6 translates to an F/MA of
approximately 0.45 on a BOD5 basis. This loading rate is typical of the Reno/
Sparks full scale secondary system.
Table 7 contains a phase average summary of the pertinent analytical
data taken during this period of operation. The data on effluent COD and sus-
pended solids shows only fair performance. This is a result of the mechanical
problems encountered during this first phase of operation on the mobile pilot
plant. The effluent quality data (appendix) shows a general trend toward im-
provement with time during Phase I. The total phosphorus data indicates that
only a 56% reduction in the influent phosphorus level was achieved across the
system. A close look at the data indicates that very little of the phosphorus
released by the organisms in the stripper appeared in the supernatant. This
low elutriation efficiency ( e= 0.15) is responsible for a high phosphorus load-
ing on the aeration basin (Fp/M^). The P/VSS level in the clarifier underflow
suggests that the uptake of phosphorus in the aeration basin was kinetically
limited since values higher than 0.044 have been achieved with the PhoStrip
process.
The clarifier underflow P/VSS ratio also indicates that approximately
1.3 mg P/l of effluent was a result of effluent suspended solids. This con-
clusion is in variance with the difference between the effluent total and ortho
phosphorus levels. There are three possible contributory factors that cause
this apparent contradiction. First, it is possible that the organisms that
47
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TABLE 6. PHASE I OPERATING CONDITIONS AT THE
PHOSTRIP PILOT PLANT, RENO/SPARKS, NEVADA
(SLUDGE RECYCLE, 11/19-12/8/75)
Feed Flow Rate, Q (m3/day)
Stripper Feed Rate, RI (m3/day)
Stripper Underflow Rate, Rg (m3/day)
Stripper Supernatant Rate, S (m3/day)
Sludge Recycle Rate (around stripper),
Waste Activated Sludge Rate (m3/day)
Retention Time Aeration (based on Q), hr.
Retention Time Anoxic (based on R3), hr.
MLSS, mg/1
MLVSS, mg/1
RlSS, mg/1
R^SS, mg/1
R3SS, mg/1
R3VSS, mg/1
TSS,'Stripper Supernatant, mg/1
VSS, Stripper Supernatant, mg/1
Dissolved Oxygen, Mixed Liquor (mg/1)
pH, Mixed Liquor
Temperature, °C
F/MA (kg COD/day/kg MLVSS)
Stripper Blanket Level, m.
Secondary Clarifier Blanket Level, m.
27.4
6.7
3.4
3.4 (12.3% of Q)
(m3/day) 2.9 (f = R2 = .43)
0.31 Rl
4.9
8.0
1370
1200
6380
5470
12,390
10,260
48
43
1.8
6.9
15.6
0.93
1.2
0.23
48
-------
TABLE 7. PHASE I AVERAGE ANALYTICAL RESULTS
AT THE PHOSTRIP PILOT PLANT, RENO/SPARKS, NEVADA
(SLUDGE RECYCLE, 11/19-12/8/75)
, mg/1
Influent 228
Effluent 47
Total Suspended Solids, mg/1
Influent 126
Effluent 36
Effluent Volatile Suspended Solids, mg/1 30
Total Phosphorus, mg P/l
Influent 8.0
Effluent (ortho) 3.5 (3.2)
Stripper Supernatant 13.6
Stripper Underflow 413
Filtered Stripper Underflow 77
Filtered Aeration Effluent 2.6
Secondary Clarifier Underflow 242
Secondary Clarifier Underflow Filtered 12
P/VSS
Secondary Clarifier Underflow 0.044
Stripper Underflow 0.033
49
-------
concentrate the phosphorus do not become equally distributed in the effluent
suspended solids and the clarifier underflow. According to Fuhs (17), organ-
isms of the genus Acinetobacter tend to form clumps which would improve
their settling characteristics. Second, the phosphorus analysis of the sludge
samples are grab samples. The level of phosphorus in the sample depends on
the conditions in the sludge during the period of sampling. Large variations
can occur as a result of the diurnal variations in influent phosphorus levels.
Finally, the effluent samples are 24-hour composites. As a consequence, the
suspended solids were maintained in an anoxic condition for up to 24 hours
without refrigeration. This set of conditions could be responsible for the re-
solubilization of significant quantities of intracellular polyphosphates. The
difference between the observed and calculated effect of suspended solids on
the effluent quality is believed to be mainly a result of a combination of argu-
ments two and three.
Further proof of the effect of grab samples appears in the determination
of phosphorus released in the stripper tank. A phosphorus mass balance
around the stripper using the change in P/VSS ratio to determine phosphorus
release results in a 63% higher level of phosphate solubilization than that
obtained by calculations made on the supernatant composite and the stripper
underflow filtered grab sample. In this case, the underflow grab sample from
the stripper approaches the equivalent of an 8-hour composite because of the
sludge recirculation mode employed while the clarifier underflow grab sample
is an instantaneous sample resulting from the pseudo plug flow nature of the
aeration basin. Therefore, the second method of calculating phosphorus re-
solubilization is more accurate. This indicates that the average P/VSS level
of the sludge leaving the secondary clarifier averaged significantly less than
the measured value.
The marginal difference between the clarifier underflow filtered phos-
phorus concentration and the stripper supernatant concentration on Table 7
may again be partially a result of comparing grab to composite samples. How-
ever, the low elutriation efficiency (e = 0.15) compared to that predicted
theoretically from Figure 8 (e -*0.23) tends to indicate that the release of
phosphorus in the sludge was inhibited (possibly by dissolved oxygen) in the
upper portion of the stripper tank. The effect of dissolved oxygen would be to
cause a rapid uptake of phosphorus by the organisms, thus reducing the quan-
tity appearing in the supernatant. The performance during Phase I is consis-
tent with the performance of the full scale plant at Reno/Sparks, Nevada be-
fore the specially modified central distribution device was added to the sys-
tem. (33)
A summary of the operating conditions for Phases II and III is presented
in Table 8. The conditions described in this table are only slightly different
from those of Phase I. Of significance is the reduction in the amount of thick-
ening which occurs in the stripper tank. A comparison of the elutriation and
50
-------
TABLE 8. PHASES II AND III OPERATING CONDITIONS
AT PHOSTRIP PILOT PLANT, RENO/SPARKS, NEVADA
Phase II Phase III
LPE LPE & Precipitation
(2/23-3/7/76) (3/20-4/2/76)
Feed Flow Rate, Q (m3/day)
Stripper Feed Rate, RI (m3/day)
Stripper Underflow Rate, R3 (m3/day)
Stripper Supernatant Rate, S (m3/day)
Elutriation Rate (m3/day)
Waste Activated Sludge Rate (m3/day)
Retention Time Aeration (based on Q)
Retention Time Anoxic (based on R3)
MLSS, mg/1
MLVSS, mg/1
RlSS, mg/1
RlVSS, mg/1
R3SS, mg/1
R3VSS, mg/1
TSS, Stripper Supernatant, mg/1
VSS, Stripper Supernatant, mg/1
Dissolved Oxygen, Mixed Liquor (mg/1)
pH, Mixed Liquor/Chemical Clarifier
Temperature, °C
F/MA (kg COD/day/kg MLVSS)
Stripper Blanket Level, m.
Secondary Clarifier Blanket Level, m.
25.7
3.8
2.9
4.8
4.1
0.39
6.0
12.5
960
870
5,390
4,500
7,730
6,550
44
37
2,0
7,1
15.
1.08
1.6
0.11
28.1
3.6
3.1
3.1 •
2.6
0.17
5.45
11.4
1070
950
8,070
7,010
10,540
8,970
34
32
1.6
7.3/9.4
16.7
1.12
1.5
0.15
51
-------
the stripper supernatant flow rates indicates that only 15% of the supernatant
flow was a result of thickening. In Phase I, 100% of the supernatant was pro-
duced through thickening. A significant addition to this table is the pH level
at which the phosphate precipitation was performed during Phase III. Since
this phase is the only one which utilized a fully closed loop system, the im-
portance of the pH level of precipitation becomes apparent as an important
factor affecting the overall performance of the process.
Table 9 contains a summary of the analytical results obtained during
these two periods of operation. The effluent COD and suspended solids level
improved substantially over that observed earlier. This was mainly due to an
improved understanding of the operational characteristics of the pilot plant.
The effluent quality of the system with respect to phosphorus also shows a
significant improvement over Phase I. A closer examination of the data indi-
cates that the improved effluent quality resulted from the higher elutriation
efficiency (e). In Phase II, approximately 71% of the phosphorus released in
the stripper was washed into the supernatant stream, while in Phase III the
efficiency approached 58%. These elutriation efficiencies reduced the phos-
phorus loading to 0.054 kg P/day/kg MLVSS in Phase II and 0.067 kg P/day/
kg MLVSS in Phase III. The previously established maximum removal rate for
this set of conditions was -^0.06 kg P/day/kg MLVSS from Phase I. Since the
rate of application of phosphorus in Phase II was below this number, consist-
ent effluent quality was achieved shortly after the system was stabilized.
Figure 16 demonstrates the stability of the effluent quality for this period of
operation. Figure 16 also shows the fluctuation of effluent quality in Phase
III. The FP/MA parameter calculated on an average basis was slightly higher
than the maximum Fp/M^ permitted by the system. Thus, an increase in the
phosphorus loading due to reduced elutriation efficiency or an increase in the
phosphorus feed level results in an increase in effluent phosphorus concentra-
tion. On March 21-23, 1976, problems were encountered in the performance
of the lime addition system. The addition of lime was hindered by erratic per-
formance of the lime slurry feed pump resulting in the inability to maintain the
pH in the quick mix tank above 8.5. Therefore, the supernatant ortho phos-
phorus concentration rose to a high of 39 mg/1 on March 23 when the pH was
measured at 7.7. This lack of pH control resulted in an increase in the Fp/M^
parameter to a point substantially higher than the 0.064 average maximum re-
moval rate. Consequently, the system was kinetically limited as the increase
in effluent phosphorus levels indicates. An improvement in the ability to con-
trol pH was achieved on the 24th, and the effluent quality improved according-
ly. However, on the 26th the maximum removal rate was again significantly
exceeded by the phosphorus loading. This time the increased load was due to
an increase in the feed phosphorus concentration. The increase was not as
great as in the previous incident, and, as a result, the effluent response was
not as pronounced.
The performance of Phase III could have been improved by increasing
52
-------
TABLE 9. PHASES II AND III AVERAGE ANALYTICAL RESULTS
AT PHOSTRIP PILOT PLANT, RENO/SPARKS, NEVADA
Phase II Phase III
LPE LPE & Precipitation
(2/23-3/7/76) (3/20-4/2/76)
CODtotal
Influent 233 241
Effluent 26 29
Total Suspended Solids, mg/1
Influent 93 98
Effluent 17 27
Effluent Volatile Suspended Solids, mg/1 14 21
Total Phosphorus, mg P/l
Influent 8.4 9.4
Effluent (ortho) 0.7 (0.5) 0.8 (0.5)
Stripper Supernatant 33 56
Stripper Underflow 216 386
Filtered Stripper Underflow 30 45
Filtered Aeration Effluent 0.8 0.8
Secondary Clarifier Underflow 190 338
Chemical Clarifier Overflow (ortho) 6.7 (3.5) 11.3 (2.4)
P/VSS
Secondary Clarifier Underflow 0.042 0.048
Stripper Underflow 0.028 0.038
53
-------
10.0-
9.0-
6.0-
x 4.0-1
QL
2.0-
1.0-
INFLUENT
PHASE IE
EFFLUENT
FEB.
11.0-
10.0-
S9'°-
^S.OH
-------
the MLVSS level, increasing the aerobic retention time or improving the elutria-
tion efficiency. In Phase III, an V value equal to 0.58 was obtained while
in Phase II, e = 0.71. The use of Figure 9 shows that the elutriation efficiency
could have been improved in Phase III by increasing the elutriation rate. When
comparing the e data in these phases to the LPE System curve of Figure 9, it is
obvious that the LPE curve is conservative relative to the performance of the
pilot plant.
Table 9 shows that the contribution of phosphorus to the effluent due to
suspended solids is less than that anticipated by the P/VSS levels in the clari-
fier underflow. Again, this is probably due to the combination of reasons
presented in the discussion of Phase I.
Table 10 summarizes the phosphorus mass balances performed around
the system for each period of intensive evaluation. Phase I shows only moder-
ate phosphorus removal due to the low fraction of phosphorus removed with the
stripper supernatant stream. In each phase the biological sludge wasting was
shown to be a significant contributor to the overall phosphorus removed by the
process. However, Phase I demonstrates that the kinetics of phosphorus up-
take prevents activated sludge wasting from efficiently removing a high frac-
tion of phosphorus from the influent. The increased elutriation efficiency is
mainly responsible for the improved performance of the last two phases since
no significant increase in phosphorus removed through sludge wasting was
observed over that in Phase I. The data for stripper supernatant P related to
Phase III represents only the phosphorus removed through chemical precipita-
tion. To determine this quantity the total phosphorus of the chemical clarifier
supernatant that was returned to the aeration basin was subtracted from the
total phosphorus of the stripper supernatant. The errors in the balances are a
result of procedural and analytical inaccuracies. However, the magnitude of
the errors are not sufficient to invalidate the conclusions which may be drawn.
The largest error exists in the determination of the accumulation term because
of the necessity for using grab samples. The accumulation term is a measure
of the change in phosphorus inventory in the aeration basin, the secondary
clarifier, and the stripper tank.
From the point of view of the process designer these data suggest that
the overall Fp/MA be maintained at less than 0.06 kg P/day/kg MLVSS with an
anoxic retention time of between 5.5 and 15 hours. Further, between 80 and
100 kg of VSS should enter the stripper tank for each kilogram of phosphorus in
the raw feed. The elutriation efficiency levels which are necessary to achieve
90% plus reduction of influent phosphorus levels will be determined by the
mass balance considerations. Generally, the required efficiency increases
with increased influent phosphorus level. The performance of the sludge re-
cycle system indicates that this system employing the conventional centerwell
distribution systems results in poor phosphorus elutriation possibly due to
inhibition of phosphorus release by the organisms in the upper portion of the
55
-------
TABLE 10. PHASE AVERAGE PHOSPHORUS BALANCE DATA
AT PHOSTRIP PILOT PLANT, RENO/SPARKS, NEVADA
Influent P, g/day
Effluent P, g/day
% of Influent
Stripper Supernatant P, g/day
% of Influent
Waste Activated Sludge Plus
Accumulated P, g/day
% of Influent
Phase I
219
96
43.7
46
20.9
81.6
37.3
Phase II
250*
18.0
7.2
158
63.2
71
28.4
Phase III
288*
24.6
8.5
175
60.7
62.5
21.7
P Balance Error, % of Influent +2.1 -1.2 -8.9
* Based on influent plus elutriation flow
-------
blanket. This inhibition may be due to the entrapment of small quantities of
dissolved oxygen with the sludge as it enters the stripper tank. The dissolved
oxygen may be a result of not being able to maintain a blanket level in the
secondary clarifier when sludge recycle is employed. Diffusion of oxygen
through the air liquid interface of the stripper may also be partially respon-
sible. The data also shows that the LPE system avoids these problems and
that the elutriation can be controlled by controlling the flow rate of the elu-
triant relative to the stripper underflow rate. The " e" curve presented in
Figure 9 is conservative relative to the LPE system's performance on this pilot
plant. The performance of the process was also shown to be a function of the
efficiency of the phosphate precipitation. The efficiency is controlled by the
pH of precipitation. A target pH of 9.4 was seen to be sufficient to produce
an ortho phosphorus level of less than 1.0 mg P/l in the chemical clarifier
supernatant.
FULL SCALE TESTING OF THE SLUDGE RECYCLE SYSTEM
The initial evaluation of the PhoStrip process at Reno was performed by
Kennedy Engineers, San Francisco, California, under the direction of L. E.
Peirano. This work began in May 1974. Incomplete phosphorus removal was
obtained until mid-September 1974, when a number of plant modifications were
incorporated into the system. Of major importance was the modification of the
inlet to the stripper as described in Section 5. From that point, the Reno/
Sparks PhoStrip modification demonstrated successful operation. (33)
On June 25, 1975, Union Carbide Corporation began its evaluation of
the PhoStrip process on the full scale plant at Reno/Sparks, Nevada. As with
the operation of the pilot plant program, a set of conditions was established on
the full scale plant and the system was allowed to come to steady state. After
steady operating conditions were achieved, a period of intensive evaluation
followed. During this intensive evaluation, Union Carbide maintained a labo-
ratory technician on site to take samples, run analyses, and generally observe
the performance of the system. The plant was operated by the staff of the
Reno/Sparks Joint Authority.
Table 11 presents a summary of the weekly analyses performed at
Reno/Sparks. Because of the nature of the diurnal variation, the analyses
were performed on the system during both the high and the low flow periods.
The high (8:00 am - 2:00 pm) and the low (2:00 pm - 8:00 am) flow periods are
characterized by fairly constant flow rates within each period. This unusual
flow variation was a result of the life style and industry in the cities of Reno
and Sparks. Figure 17 contains a flow diagram of the system along with the
identification letters referred to in Table 11. During this test period, one-
third of the plant was operated with the PhoStrip process and the remainder was
used as a control. From the schedule in Table 11, it can be concluded that a
57
-------
TABLE 11. WEEKLY ANALYTICAL SCHEDULE - RENO/SPARKS, NEVADA
LOCATION OR STREAM:
Parameter
Flow Min. (Avg)
Max. (Avg)
pH Min.
Max.
TSS Min.
Max.
CO EH- Max.
en Temp. Min.
00 Max.
D.O. Min.
Max.
TP+ Min.
Max.
Ortho-P Min.
Max.
A B
FEED EFFLUENT
7* 7
7 7
7G 7G
7G 7G
7C 7C
7C 7C
1 1
3 3
7C 7C
7C.F 7C,F
C
AEROBIC
RECYCLE
7
7
7G
7G
7+
7+
7
7
7
7F
7F
SECONDARY CIARIFIER
Blanket Depth: Min.
Max.
7
7
D
ANOXIC
RECYCLE
7
7
7G
7G
7+
7+
7
7,7F
7,7F
7F
7F
STRIPPER
7
7
E
STRIPPER
SUPERNATANT
7
7
7G
7G
7+
7+
7
7
7
7F
7F
F G H I
WASTE AERATION BAY STRIPPER
SLUDGE 1/3 2/3 END SLUDGE RECYCLE
7 7
7 7
4G
7
7
7
1 1 1
3 33
3F 3F 3F
3F 3F 3F
3F 3F 3F
3F 3F 3F
* = Times/Week G = Grab
C = Composite F * Filtered
+ = Analyses performed at Tonawanda
Min = Low flow period of diurnal pattern
Max = High flow period' of diurnal pattern
-------
U1
10
CULATION
ANOXIC RECYCLE
STRIPPER
SUPERNATANT
A
PRIMARY EFFLUENT
V
AEROBIC RECYCLE
SECONDARY EFFLUENT
Figure 17. Reno/Sparks - sampling points and flow diagram.
-------
complete evaluation of the system with respect to flows, pH, D.O., TSS, and
phosphorus concentration was to be made. An overall evaluation of COD re-
moval was also done.
After becoming familiar with the performance characteristics of the full
scale plant, Phase I of the full scale evaluation was begun. The abnormal
flow variation (near maximum flow for 18 hrs/day and near minimum flow for 6
hrs each day), coupled with the inability to maintain a blanket level in the
secondary clarifier, resulted in less than ideal operating conditions. Condi-
tions similar to those presented in Table 12 were established on August 14,
1975. The relative areas of the secondary clarifier and stripper tank made the
maintenance of a sludge blanket in the secondary clarifier impossible. Ideally,
the stripper feed and underflow rates should be maintained constant in order to
minimize operator control. However, in situations of significant long term
flow differences, this can only be accomplished if excess sludge storage
capacity is available either in the secondary clarifier or the stripper tank. If
the system is maintained with zero blanket level in the secondary clarifier
during the high flow period, then, at constant stripper flow rates, the blanket
level in the stripper will drop during the low flow period due to an increase in
mixed liquor suspended solids. If the blanket level drops such that a minimum
required anoxic period is not maintained, the ability of the system to remove
phosphorus will be impaired.
There are two ways of maintaining sufficient stripper blanket levels at
constant stripper flow rates in systems with prolonged periods of diurnal vari-
ation and while maintaining essentially a zero blanket level in the secondary
clarifier. The most obvious is to design excess storage capacity into the
stripper tank. For example, in the Reno/Sparks situation, a design of 10 hrs
anoxic period may be extended to 14 hrs to insure against too short of an
anoxic period during low flow conditions. The second technique utilizes the
direct recycle stream (RD in Figure 11) to maintain a constant MLSS level in
the aeration tank.
The first control method, excess stripper tankage, represents an in-
creased capital cost which should not be necessary in any but the smallest
of plants where operational efforts are generally minimized. The second
alternative was not employed at the Reno/Sparks plant because of operational
limitations. The capacity of the recycle pumps dictated that higher recycle
rates (MLSS levels) were necessary to utilize this scheme. These MLSS
levels were not allowable because the characteristics of the wastewater are
such that extensive foaming results when the MLSS and associated aeration
rates are increased. This situation was observed for the system with and
without the PhoStrip modification. The control system used in this case, as
well as during the LPE system testing, employed changes in the stripper
throughput to maintain a fairly constant MLSS level in the aeration basin and
thus maintain a minimum anoxic period in the stripper tank. This situation
60
-------
TABLE 12. OPERATING CONDITIONS FOR THE PHOSTRIP
SLUDGE RECYCLE SYSTEM - FULL SCALE TESTING
AT RENO/SPARKS, NEVADA (9/13/75-9/27/75)
Parameter Minimum
Flow Rates (m3/day)
Feed, (Q)
Recycle to Stripper (R,)
Stripper Underflow (R3)
Stripper Supernatant
Recirculation Rate (R2)
Waste Sludge Rate
Aeration Time, Hr. (based on Q)
Anoxic Period, Hr. (based on R3)
MLSS, mg/1
MLVSS, mg/1
RjSS, mg/1
RiVSS, mg/1
R3SS, mg/1
R3VSS, mg/1
TSS Stripper Supernatant, mg/1
VSS Stripper Supernatant, mg/1
D.O., End of Aeration, mg/1
D.O., Rlf mg/1
D . O . , R3 , mg/1
pH, End of Aeration Basin
pH, RI
PH, R3
pH, Stripper Supernatant
Temperature, °C
F/Ma (kg COD/day/kg MLVSS)
Clarifier Overflow Rate, m/day
Clarifier Blanket Level, m.
14,690
5,180
2,330
2,850
4,230
639
10.2
16.
-
-
3,060
2,480
9,620
7,700
65
50
-
0.4
0.3
-
6.8
6.4
6.6
23
—
22.4
0.08
Time
Weighted
Maximum Mean
25,060
7,340
4,150
3,200
2,420
639
6.0
9.4
-
-
4,620
3,740
9,120
7,300
90
69
1.5 (0.7-2.2)
0.7
0.3
7.0
6.8
6.4
6.5
23
—
38.2
0.09
22,460
6,830
3,630
3,110
2,850
639
7.1
11.0
1,150
900
4,230
3,420
9,250
7,340
84
64
-
0.6
0.3
-
-
-
^
23
0.96
34.3
0.09
61
-------
typifies the importance of utilizing an overall systems approach to designing
the activated sludge-PhoStrip system. Although the processes will perform
well if designed independently, some of the flexibility and ease of operation
may be sacrificed. The mode of operation at Reno/Sparks was dictated by the
size of the existing tanks, pumps and flowmeters. Had the PhoStrip and acti-
vated sludge systems been designed to complement each other, the need to
change flow rates around the stripper tank could have been eliminated.
The information presented in Table 12 is representative of the train
modified for the PhoStrip process and is consistent with the performance of the
control system which was operated independently (appendix). The significant
difference in the anoxic retention times for the minimum and maximum flow
periods is a result of the change in flow rate of the stream leaving the stripper
tank. The volume of the sludge in the stripper tank was maintained at a rela-
tively constant level.
Table 13 presents the average data obtained with respect to COD, sus-
pended solids and total phosphorus. The system demonstrated excellent ef-
fluent quality in all respects. The effluent suspended solids level of 13 mg/1
compares with the 14 mg/1 of the control system. It is interesting to note that
the difference between the effluent total and ortho phosphorus coincides
closely with that predicted from the product of effluent volatile suspended
solids and the P/VSS level for the flow weighted mean. This was mainly due
to the fact that the composite samples were made up of periodic grab aliquots
which were refrigerated immediately after being taken. The refrigeration sig-
nificantly reduced the amount of phosphorus released during storage.
The extremely low filtered aeration effluent ortho phosphorus (0.04
mg/1) has been observed in other locations and is an indication of the poten-
tial removal capability of the process. The difference between this value and
the ortho phosphorus in the final effluent is due to two factors. The filtered
aeration effluent is a grab sample while the effluent ortho is a composite.
Further, the low D.O. at the end of the aeration basin results in the initiation
of phosphorus release in the secondary clarifier. The ortho phosphorus in the
effluent is most likely resolubilized poly phosphates. Therefore, lower effluert
levels could have been achieved by operating the tail end of the aeration basin
at a higher dissolved oxygen level. The effluent quality could have also been
improved by increasing the elutriation efficiency. The elutriation efficiency
achieved during this period of operation was approximately 38%. Thus, most
of the phosphorus released from the sludge in the clarifier was returned to the
aeration basin to be taken up again. Higher elutriation efficiencies would
have reduced the P/VSS level of the solids in the effluent. As a result, the
effluent total phosphorus level would approach the measured ortho phosphorus
concentration.
Figures 18 and 19 present a graphical interpretation of the influent and
62
-------
TABLE 13. ANALYTICAL RESULTS FOR THE PHOSTRIP
SLUDGE RECYCLE SYSTEM FULL SCALE TESTING
AT RENO/SPARKS, NEVADA (9/13/75-9/27/75)
Parameter
COD, mg/1
Influent
Effluent
Total Suspended Solids, mg/1
Influent
Effluent
Effluent Volatile Suspended Solids, mg/1
Total Phosphorus, mg P/l
Influent
Effluent (ortho)
Stripper Supernatant
" Stripper Underflow
Filtered Stripper Underflow
Filtered Aeration Effluent (ortho)
Secondary Clarifier Underflow
P/VSS
Secondary Clarifier Underflow
Stripper Underflow
Minimum
187
40
-
19
13
9.6
1.0 (.3)
44
257
67
-
104
0.042
0.025
Maximum
266
37
-
13
10
9.1
0.8 (.4)
41
240
55
- (.04)
161
0.043
0.025
Flow
Weighted
Mean
253
37
113
13
10
9.2
0.8 (.4)
42
247
58
-
113
0.043
0.025
63
-------
22 -
20 -
I 8 -
I 6 -
I 4 -
•> i Hi*
5" 12-
CO
ID
OC
O
X
o.
CO
O
X
a.
0 -
8 -
6 -
4 -
0
INFLUENT TOTAL = A
EFFLUENT TOTAL= 0
EFFLUENT ORTHO= O
I i I \ i i i i i i i i i i i i
12 13 14 15 16 17 18 19 2021 22 23 24 25 26 27
SEPTEMBER, 1975
Figure 18. Reno/Sparks full scale phosphorus data obtained during minimum
flow period (16% of the total volume treated by the PhoStrip system).
64
-------
er
o
x
OL
CO
O
X
a.
22-
20 -
1 8 -
16 -
I 4 -
I 2 -
10 -
8 -
6 -
4 -
2 -
INFLUENT TOTAL
EFFLUENT TOTAL -D
EFFLUENT ORTHO =O
i i i I i i T i i i i i I i I
12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27
SEPTEMBER, 1975
Figure 19. Reno/Sparks full scale phosphorus data obtained during maximum
flow period (84% of the total volume treated by the PhoStrip system).
65
-------
effluent phosphorus data for the minimum and maximum flow periods respec-
tively. The higher effluent total phosphorus data during the first four days was
a result of the lower supernatant flow rates employed in the earlier part of the
test. Of significance is the fact that the system demonstrated the ability to
handle prolonged peak loadings (6 hrs. at 21 mg P/l) without significantly
affecting the effluent quality. This is a result of the organisms' ability to
take up large quantities of phosphorus over and above the .043 P/VSS level
exhibited as an average. The effect of the high influent phosphorus levels
observed for September 24 and 25 during the low flow periods did not substan-
tially affect the effluent levels during the maximum flow interval. Since the
maximum flow period represents an average of 84% of the liquid treated by the
process, the flow weighted effluent phosphorus for these two days is very near
1 mg/1.
The overall phosphorus balance for Phase I of operation is presented in
Table 14. Ninety-one percent of the phosphorus was removed from the waste-
water. About 63% of the influent was removed through the supernatant stream,
while almost 35% was removed with the waste activated sludge. The error in
the phosphorus balance is mainly a result of the use of grab samples for the
sludge wasting and accumulation term.
A comparison between the control system and the PhoStrip system at
Reno/Sparks has been published by Peirano (31) at various operating condi-
tions. Therefore, extensive testing of the control system was not performed
during this evaluation. However, Table 15 presents data used to determine
the P/VSS level in the sludge from the control system during the period of
operation under discussion. The calculations presented in the table show that
phosphorus content of the sludge in the control was approximately 2.4% of the
VSS. Since approximately the same mass of volatile suspended solids was
wasted from the PhoStrip and control units, and since the phosphorus loading
(kg/day) to the two units was identical, the control system removed approxi-
mately 19.5% of the influent phosphorus. This removal was accomplished
through sludge wasting alone. This is equivalent to an effluent phosphorus
level of 7.4 mg P/l for the control system during this phase of operation.
A comparison of the data between the full and pilot scale systems run
in the sludge recycle mode indicates a significant improvement in performance
for the full scale system. At similar operating conditions the full scale sys-
tem achieved an effluent phosphorus level less than 1.0 mg/1 while the pilot
system was able to achieve only 3.5 mg P/l of effluent. The phosphorus
balances for the two systems indicate that both systems removed nearly the
same fraction of the influent phosphorus through wasting of the activated
sludge. However, the pilot unit removed only 20.9% of the influent phosphorus
through the supernatant while the full scale system removed 63.2% of the
phosphorus through this stream. This difference is mainly a result of the per-
formance of thestripper tanks with respect to elutriation efficiency. In the
66
-------
TABLE 14. PHOSPHORUS BALANCE DATA FOR THE
FULL SCALE TESTING AT RENO/SPARKS, NEVADA
PHOSTRIP SLUDGE RECYCLE SYSTEM
Influent Phosphorus, kg/day 206.7
Effluent Phosphorus, kg/day 18.0
, % of Influent 8.7
Stripper Supernatant P, kg/day 130.6
, % of Influent 63.2
Waste Plus Accumulated P, kg/day 72.2
, % of Influent 34.9
Phosphorus Balance Error, % of Influent +6.8
67
-------
TABLE 15. SLUDGE PHOSPHORUS CONCENTRATION
OF THE CONTROL SYSTEM - FULL SCALE TESTING
AT RENO/SPARKS, NEVADA
Date
9-15-75
9-17-75
9-19-75
Mean
°L P ir
TSS
ML
1452
1276
1044
1260
i o r\\ I A e* — —
, MG/L
Recycle
6260
5220
6084
5850
C(TP) - (SOL
VSS
ML
1060
1022
844
980
TP)1
, MG/L
Recycle
4744
4290
5676
4900
100
TPO4-
ML
35
37
22
31
P, MG/L
Recycle
116
110
142
122
Mixed Liquor SOL TP * 7.2 mg/1*
Mixed Liquor = <31'3 -?'2> 10° = 2.4%
you
Recycle .
* obtained from a mass balance around control system.
68
-------
pilot system only 15% of the phosphorus which was released by the sludge in
the stripper made its way to the supernatant. Thirty-eight percent of the phos-
phorus released in the full scale stripper was removed through the supernatant
stream. Since the two stripper tanks were run at nearly the same conditions,
the improved elutriation efficiency was a result of the change in scale. The
sludge recycle system runs more efficiently at higher tank diameter-to-depth
ratios. The higher ratios, coupled with the design of the stripper influent
mechanism used at Reno/Sparks, may have caused the solids in the stripper
tank to roll somewhat. As a result, the released phosphorus sludge was more
evenly distributed throughout the tank and thus could more easily diffuse to
the supernatant. The theoretical elutriation efficiency for the conditions of
the full scale system would predict an e = 0.22 according to Figure 9. For the
purpose of designing, it is recommended that the theoretical elutriation effici-
ency curves be used because of the uncertainty of the effect the sludge distri-
bution device had on the performance of the stripper tank.
FULL SCALE TESTING OF THE LPE SYSTEM
The evaluation of the full scale LPE system was originally to last
twelve months and was to be divided into four phases. The first phase was
preliminary testing of 50,000 mVday. The second was a long term intensive
evaluation at 50,000 m^/day. The third and fourth phases were to test per-
formance at 76,000 mVday. As was discussed earlier, the duration of the
-program was cut due to a water quality study on the Truckee River. As a re-
sult, only the preliminary 50,000 m3/d program was completed.
During PhoStrip operation the raw degritted sewage was settled in the
number 2 and 3 primary basins and then evenly split and discharged to the
three aeration basins. Each basin is split into three tanks and operated in a
serpentine plug flow manner. After aeration, the mixed liquor was discharged
to three independent secondary settling tanks. The effluent was post-aerated
and chlorinated prior to discharge.
The PhoStrip system was prepared for the demonstration project during
August and September of 1976. An elutriation pump was installed so that pri-
mary effluent could be used for washing the solubilized phosphorus from the
sludge in the stripper tank. An additional pump was purchased and installed
for the purpose of removing the phosphorus-rich supernatant from the stripper
and discharging it to the head end of the third aeration system. The number 1
and 2 systems operated on PhoStrip while the number 3 did not.
The return activated sludge from the number 1 and 2 secondary clari-
fiers was pumped to the stripper with some sludge bypassed directly to the
aeration basins. Sludge from the stripper was pumped to and split evenly
betwen the number 1 and 2 aeration basins, thus completing the cycle.
69
-------
Figs. 20 & 21 diagramatically present the configuration of the PhoStrip
system during this phase of the demonstration project. All flows were metered
and volumes integrated. Suitable valves were installed for adjusting flows to
and from the stripper and in the secondary sludge return bypasses to the aera-
tion basins.
Sludge depths in the secondary clarifiers and the anoxic stripper were
measured six times daily and used to control stripper sludge flow and wasting
rates. It was important to maintain adequate sludge blankets in the secondary
clarifiers so that sludge would properly thicken. The stripper was operated to
maximize anoxic retention volumes (less than 0.9m freeboar4 water).
The initial period of operation was for the purpose of optimizing overall
system performance, minimizing the volume of supernatant and acclimating to
cold weather conditions. Samples were taken and analyses performed in the
Reno/Sparks treatment plant laboratory and at Union Carbide's Tonawanda
laboratory. The analytical schedule is included as Table 16. Additional data
were taken as a normal part of the plant's monitoring schedule. Flow rates in
the PhoStrip system were noted daily.
A Union Carbide engineer was located at the facility during this pro-
ject. His responsibilities were to supervise the operation of the retrofitted
PhoStrip system, collect samples and perform necessary analyses.
The PhoStrip system had been initially started up during October 1976
and operated by plant personnel until the start of the project on November 22,
1976. From November 22, 1976 to early January 1977 various operating condi-
tions were tested to determine the response of the system to different modes
of operation. On January 13, 1977 the conditions were changed to those neces-
sary to achieve performance for the planned Phase II intensive evaluation. The
data presented in Tables 17, 18 and 19 are from the steady performance
achieved during Phase I prior to shutting down the system.
Table 17 presents the steady state operating conditions obtained prior
to the termination of the program. As with the sludge recycle case, the fact
that the PhoStrip system was a temporary add-on resulted in operations that
were not optimum. Again, the flow rates around the stripper tank had to be
changed as a function of the high and low flow periods during the day. This
flow rate change was necessitated by a change from the influent flow patterns
normally observed at the plant. Normally, the speeds of the two pumps in the
wet well of the pumo station that feeds the plant are automatically varied to
pace with the incoming flow. However, during the demonstration project the
motor speed control centers were inoperative and the pumps could only be
operated at full speed. By using the interceptors as a continuation of the wet
well, the plant was operated in a one pump/two pump mode. This method of
operation resulted in step changes in the flow rates between the minimum and
70
-------
A
\
\
N
A
r>
A
\
\
N
A
! i
STRIPPER
f
^
ELUTRIANT
SUPERNATANT TO *3 AERATION BASIN
#
A
A
EFFLUENT
TO POST-
AERATION
SECONDARY
CLARIFIERS
AERATION
BASINS
PRIMARY
BASINS
Figure 20. Flow diagram of PhoStrip LPE system at Reno/Sparks, Nevada.
71
-------
ELUTR1ANT >
DISTRIBUTION VALVE
DISTRIBUTION WELL
DISTRIBUTION ARMS
Figure 21. Stripper tank and elutriant distribution system.
-------
NJ
CO
TABLE 16. ANALYTICAL SCHEDULE FOR FULL SCALE TESTING
AT RENO/SPARKS, NEVADA - PHOSTRIP LPE SYSTEM
SAMPLE LOCATION BODg
Primary Effluent 2+
Secondary Effluent
Clarifier No. 1 2
Clarifier No. 2 2
Aeration Basin (end)
Tank No. 1
Tank No. 2
Stripper Supernatant 1
Anoxic Sludge Recycle
Aerobic Sludge Recycle*
Tank No . 1
Tank No. 2
TSS
7
7
7
7
7
2
1
7
7
VSS
1
1
1
1
1
2
1
1
1
pH ' TKN
5
5
5
3
3
5
TP
5
5
5
5
1
1
1
OP**
5
5
5
3
3
5
3
TYPE
C
C
C
G
G
C
G
G
G
C
G
*
**
= analyses/week
= 24 hr. composite
= grab
= two grab samples: one at high flow, one at low flow
= mixed liquor soluble ortho phosphates were measured 3 times per week
(Flow rates are normally taken as part of plant operating data.)
-------
TABLE 17. OPERATING CONDITIONS FOR FULL SCALE TESTING
AT RENO/SPARKS, NEVADA
PHOSTRIP LPE SYSTEM (JANUARY 18-30, 1977)
MINIMUM
PARAMETER TRAIN I/TRAIN 2
Flow Rates, m /day
Feed Q, (each train)
Recycle to Stripper, RI
Stripper Underflow, R3
Stripper Supernatant, S
Elutriation, EL
Total Aerobic Recycle, Rj + Rdirect
Sludge Wasting
Aeration Time , Hrs . (based on Q)
Anoxic Period, Hrs. (based on R3)
MLSS, mg/1
VSS/TSS
RlSS, mg/1
VSS/TSS
R3SS, mg/1
R3VSS, mg/1
TSS Stripper Supernatant, mg/1
VSS Stripper Supernatant, mg/1
pH, Mixed Liquor, mg/1
Temperature (Influent), *C
F/Ma (kg BOD5/dayAg MLVSS)
Secondary Clarifier Overflow Rate,m/day
Clarifier Blanket Level, m.
17280/17280
1987/2160
1210/1470
6570
5270
-
-
9.0/9.0
11.6
1230/1280
0.8
5750/5460
0.78
8930
7360
-
-
7.1/7.0
13
0.45
26.4/26.4
-
MAXIMUM*
TRAIN I/TRAIN 2
29380/29380
3200/3370
2250/2250
7000
5620
-
-
5.1/5.1
7.0
1110/1140
0.8
6770/6720
0.78
8310
6590
-
-
7.0/7.0
13
0.88
44.8/44.8
-
FLOW
WEIGHTED MEAN
TRAIN I/TRAIN 2
22460/22460
2510/2680
1640/1810
6740
5440
4490/5530
331/418
6.8/6.8
9.5
1170/1220
0.8
6210/6030
0.78
8650
7010
59
54
-
13
0.62
34.3/34.3
<0.2
* duration at max. flow » 11 hrs/day
74
-------
maximum flow period as well as an increase in the duration of the low flow
period from .^6.0 to ^13 hours.
With the LPE mode of operation, it is desirable to operate without any
thickening occurring in the stripper tank. A comparison of elutriation flow rate
and the stripper supernatant flow indicates that this was not accomplished dur-
ing this phase of the program. The clarifier and stripper underflow suspended
solids levels further confirm this point. Attempts to increase the blanket level
in the secondary clarifier above 0.2m were very successful with respect to
increasing the RjSS level to that of the R^SS concentration. However, the RSR
(rapid sludge return) units designed into the secondary clarifier were not able
to handle the higher TSS levels. The arms of the units would plug and the re-
turn sludge flows were disrupted.
The retention time in the stripper was limited by the amount of volatile
solids that had to be put through the anoxic period to achieve the desired phos-
phorus removal and the size of the primary clarifier employed as the stripper
tank. Slightly longer (increased 1 to 2 hr) would be more desirable for the
operating temperature of this system (138C).
The average analytical results observed during this period of operation
are contained in Table 18. The effluent BOD5 and suspended solids levels are
typical of those obtained from activated sludge systems and are comparable
with those obtained from reactor #3 which was not operating in the PhoStrip
mode (Appendix). The phosphorus data indicates that the LPE system was able
to achieve a high quality effluent while treating two-thirds of the total plant
flow. As with the pilot plant data, the difference between the effluent total
and ortho phosphorus levels does not agree with that predicted by the effluent
total and ortho phosphorus levels and does not agree with that predicted by
the effluent volatile suspended solids and the P/VSS ratio of the clarifier un-
derflow. Because of the larger number of samples taken with two trains opera-
ting in the PhoStrip mode, it was not possible to refrigerate the effluent sam-
ples. Consequently, a large fraction of the ortho phosphorus in the effluent
samples resulted from resolubilization of the poly phosphate within the effluent
suspended solids. The other factors mentioned earlier may have also contribu-
ted to this difference.
Figure 22 graphically displays the influent and effluent phosphorus
levels achieved during the two week steady state period. This effluent quality
could have been improved by running the system at longer stripper SRT levels.
This would have resulted in more phosphorus release in the stripper tank and,
therefore, more phosphorus removed with the supernatant. Increasing phos-
phorus removal through the supernatant reduces the P/VSS level of the sludge
and would result in less effluent phosphorus due to suspended solids. The
size of the stripper tank at Reno/Sparks did not permit operations at longer
retention times with the required sludge throughput. Reducing the sludge
75
-------
TABLE 18. ANALYTICAL RESULTS FOR FULL SCALE TESTING
AT RENO/SPARKS, NEVADA
PHOSTRIP LPE SYSTEM (JANUARY 18-30, 1977)
PARAMETER
FLOW
MINIMUM MAXIMUM WEIGHTED MEAN
TRAIN I/TRAIN 2 TRAIN I/TRAIN 2 TRAIN I/TRAIN 2
BOD5, mg/1
Influent
Effluent
Total Suspended Solids, mg/1
Influent
Effluent
Effluent Volatile Suspended Solids, mg/1
Total Phosphorus, mg P/l
Influent
Effluent (ortho)
Stripper Supernatant
Stripper Underflow
Filtered Stripper Underflow
Secondary Clarifier Underflow
P/VSS
Secondary Clarifier Underflow
Stripper Underflow
255
50
215/195
.048/.046
0.028
270
70
280/250
.053/.048
0.030
168
28/29
102
21/23
9.1
0.8(.5)/0.9(.6)
36
260
59
245/220
.05/.047
0.029
-------
12-,
I-
ICH
9-
8-
>
E
7-
^ 6-
cr
o
a 5.
O
X
Q.
4-
3-
2-
INFLUENT=A
EFFLUENT*! -D
EFFLUENT*2 -O
,O
O
I I I r i i i r ITI ii
18 19 20 21 22 23 24 25 26 27 28 29 30
JANUARY, 1977
Figure 22. Reno/Sparks full scale phosphorus data for LPE system.
77
-------
throughput would increase the retention time but would also increase the amoint
of phosphorus that would have to be released per unit of mass sludge trans-
ferred to the stripper. Thus, only a modest reduction, if any, in the P/VSS
level could have been achieved in this manner. A stripper tank with the same
cross sectional area but larger volume (more depth) would have been a more
effective system.
The phosphorus removed through the supernatant could have been in-
creased by improving the elutriation efficiency of the system. As the system
was operated, nearly 59% of the phosphorus released in the stripper tank
appeared in the stripper supernatant. From Figure 9 it can be seen that an in-
crease in elutriation efficiency can be achieved by increasing the elutriation
flow rate. An increase in elutriation efficiency done in this manner results in
an increased chemical cost due to a larger stripper supernatant flow. The re-
sults of this phase of operation represent the minimum elutriation flow allow-
able for the tankage volume and elutriation distribution system used. A taller
stripper tank would have allowed the elutriation flow rate to be reduced. A
stripper tank with a smaller cross sectional area or a sludge return system that
could handle higher solids concentration would have resulted in less thicken-
ing and, therefore, a further reduction in the supernatant flow rate and the
associated chemical costs.
Table 19 summarizes the results of the mass balance performed on the
data obtained during this- phase of operation. Unlike the data for the sludge
recycle system, the influent phosphorus mass rate depends on the feed to the
aeration basin and the elutriation flow rate because primary effluent was used
as the elutriant. The high P/VSS of the system manifests itself in the amount
of phosphorus removed through activated sludge wasting. As indicated earlier,
most of the error in the mass balance is in the waste plus accumulation term
because of the necessity for using grab samples on these streams.
A comparison between the LPE and sludge recycle systems indicates
that the LPE system was capable of producing the same quality effluent while
utilizing the same stripper tank, but handling twice the flow at a lower tem-
perature. The main reason for this is an improvement in elutriation efficiency
with the LPE system ( e = 0.59 vs. e =0.38). This increase in elutriation
efficiency was achieved with no significant increase in the percent of influent
flow appearing in the supernatant from the stripper. The LPE system removed
more phosphorus through activated sludge wasting than the sludge recycle sys-
tem due to the higher P/VSS ratio in the sludge. However, the P/VSS ratio is
a controllable parameter which was restricted by the conditions resulting from
the requirement of using existing tankage.
78
-------
TABLE 19. PHOSPHORUS BALANCE DATA FOR
FULL SCALE TESTING AT RENO/SPARKS, NEVADA
PHOSTRIP LPE SYSTEM (JANUARY 18-30, 1977)
Influent Phosphorus , kg/day 458.3
Effluent Phosphorus, kg/day 38.2
, % of Influent 8.3
Stripper Supernatant P, kg/day 242.6
, % of Influent 52.9
Waste Plus Accumulation P, kg/day 168.6
, % of Influent 36.8
Phosphorus Balance Error, % of Influent - 2.0
* feed to aeration plus elutriation
79
-------
PROCESS DESIGN CONSIDERATIONS
Kinetics
As was mentioned in Section 4, there are two major considerations re-
stricting the performance of the PhoStrip process with respect to uptake and
release: kinetics, and the phosphate saturation level in the sludge. Once the
kinetics of the process are understood, the use of mass balances as one of the
design tools can result in a design which prevents the system from approach-
ing too near the saturation level of the sludge. Designing a system for a
P/VSS ratio of less than 0.04 will insure ample safety with regard to saturation
level and produce an effluent quality of less than one mg phosphorus per liter
for most activated siudge systems.
The kinetic rate values for the data obtained from both pilot and full
scale operations are presented in Table 20. These values were obtained by
assuming zero order reactions relative to the soluble phosphate concentration.
(23-25) Data from the preliminary operational periods of the LPE System were
also used to help define these values. Figure 23 shows the relationship
obtained for the uptake rate values as a function of temperature. It is recom-
mended that this relationship be utilized in the design of activated sludge
systems at F/M levels ranging from 0.3 to 0.7 kg BODs/day/kg MLVSS.
The data in Table 20 indicates that the full scale LPE system produced
a release rate (k^) that was nearly 100% greater than that of the pilot scale
LPE system. A comparison between the pilot and full scale sludge recycle
systems indicates that there was no significant difference between the two
units with respect to release rate values. Since the full scale sludge recycle
study exhibited nearly the same kR value as the pilot scale LPE system, the
full scale LPE system was more efficient than the sludge recycle system with
respect to phosphorus release. The exact explanation for this cannot be
obtained from these data. It is recommended that a kR value of .03 be utilized
for designing PhoStrip systems with anoxic sludge retention times ranging
between 5.5 and 15 hours. This rate represents a significant safety factor for
the LPE system but none for the sludge recycle system.
Elutriation Efficiency
As was discussed earlier, the sludge recycle system operating on the
full scale system exhibited significantly higher elutriation efficiencies than
the pilot scale system and moderately higher than the theoretical model would
predict. The use of the theoretical model provides a 1.7 safety factor over
the full scale data and is therefore recommended for designing the process.
The efficiency of the LPE system for the full scale demonstration study
is compared to the pilot scale correlation in Figure 24. Generally, the pilot
80
-------
TABLE 20. KINETIC CONSTANTS AND ELUTRIATION EFFICIENCIES
AT RENO/SPARKS, NEVADA (NOVEMBER 1976 - JANUARY 1977)
00
PILOT PLANT
FULL SCALE
SLUDGE SLUDGE RECYCLE LPE
RECYCLE STEADY STATE WEEK BEGINNING
KINETIC VALUES
*u
*R
e
Y
Mixed Liquor Temp. , *C
RTS. Hrs.
PHASE I PHASE II PHASE III PHASE
.06
.03
.15
1.0
16
8.0
.05
.02
.71
1.4
15
6.0
ku = uptake rate kg P/day/kg MLVSS
k^ = release rate kg P/day/kg VSS in
e - elutrlatlon efficiency
Y = supernatant flow/stripper
.06 .07
.02 .03
.58 .38
.8 .9
17 23
S.5 11.0
stripper
underflow, or
11/21 11/28 12/5
I.D. I.D. .06
.06 .05 .05
.36 .36 .38
.8 .9 .6
15 12 13
6.6 6.8 5.9
Notes;
No data was
12/12
I.D.
I.D.
I.D.
.9
12
5.9
taken
I.D. = Insufficient
12/26 1/2 1/9
.05 .05 .05
.05 .04 .04
.68 .55 .49
2.7 1.1 .9
12 13 13
14.4 12.7 10.6
on 12/19.
data
STEADY STATE
PHASE
.05
.04
.59
1.6
13
9.5
KI,
elutriation flow/stripper underflow
retention time in stripper based on
-------
.03-.
.02-
03
3-09-
h-
<
c/)
o
LU.05-
UJ
ID
oc
O
£.02-1
c/)
O
X
CL
D LPE FULL SCALE
A LPE PILOT SCALE
O SLUDGE RECYCLE FULL SCALE
• SLUDGE RECYCLE PILOT SCALE
ku= .066 x 1.037
(T-20)
12 13 14 15 16 17 18 19 20 21 22 23
TEMPERATURE,°C
Figure 23. Phosphorus uptake rate constant versus temperature
(Reno/Sparks, Nevada).
82
-------
Q
UJ
<
UJ
-J
UJ
.8
.7 -
.6 -
.5 -
o
z
UJ
Q_
O CT*
uls* .4
.3 -
o:
ui
o.
2 .2 -
PILOT SCALE CORRELATION
Y
FULL SCALE DATA
.4
r=
.8 1.2 1.6 2.0
ELUTRIATION FLOW RATE
STRIPPER UNDERFLOW RATE
2.4
2.8
Figure 24. Elutriation efficiency for the LPE modification.
83
-------
and full scale data compare rather well at low y values while significant devi-
ation occurs when y exceeds 1.1. Figure 24 also contains an equation re-
lating elutriation efficiency to y • This equation was obtained from a least-
squares curve fit of the data, and is recommended for design usage. The
safety factor for the LPE system is incorporated in the release rate constant and
is equivalent to a safety factor of 2.0 for the overall process design. Theo-
retically, the elutriation efficiency for the LPE system will improve with in-
creased stripper height at the same anoxic sludge residence times (smaller
cross section area). It is anticipated that systems with more than the 2.0m
of sludge blanket available during this study will exhibit higher efficiencies
than those shown in Figure 24.
Settling Characteristics of the Biological Sludge
In order to adequately design the PhoStrip process, it is necessary to
know the settling characteristics of the sludge so that the stripper cross
sectional areas can be determined for a desired throughput. Further, the opti-
mum performance of the LPE modification can only be achieved if no increase
in suspended solids concentration is allowed to occur from the stripper feed
stream to the stripper underflow. Therefore, best performance can be achieved
with the minimum possible stripper cross sectional area which allows for suf-
ficient anoxic sludge residence time and mass throughput. If safety factors are
applied to stripper tank design for this system, they should result in an in-
crease in stripper height, not cross sectional area. However, the safety factor
incorporated into the release rate is sufficient that no safety factor should be
applied directly to the sizing of the stripper tank.
Ideally, the settling constants for the design of the stripper tank
should be obtained from a PhoStrip pilot plant program. In lieu of such data, it
can be assumed that the settling constants are equivalent to those character-
istic of the activated sludge system to be employed. Again, the safety factors
in the elutriation efficiency for the sludge recycle system and the release rate
constant for the LPE system will be sufficient to provide a safe design if
reasonable settling constants are employed.
84
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SECTION 7
LIME REQUIREMENTS, CHEMICAL SLUDGE PRODUCTION,
AND CHEMICAL SLUDGE DEWATERING
Precipitation of phosphorus utilizing lime (CaO) is an integral part of
the PhoStrip process. As discussed in Section 4, there are only a limited
number of cases where low effluent phosphorus levels are achievable without
the use of a chemical precipitant. The example presented in Figure 6 showed
that nearly 82% of the phosphorus removed from the raw wastewater was con-
centrated in the waste chemical sludge.
The principal forms of phosphorus in wastewaters are the ortho phos-
phate ion, poly phosphates, and organic phosphates. The activated sludge
process converts the organic phosphates and poly phosphates to the ortho
form through biochemical activity. In the PhoStrip process, this ortho phos-
phorus is taken up in the aeration basin and released back into solution in
the anoxic stripper tank. Thus, phosphorus in the ortho form is the material
that is precipitated from the stripper supernatant stream.
Lime is employed as the precipitant in this process because of its low
cost and the fact that phosphate precipitation with lime is pH dependent and
independent of the phosphorus concentration. As presented in the EPA Process
Design Manual for Phosphorus Removal (34), the relationship of total residual
phosphorus with pH for secondary effluents is given by equation (14).
Log P = 3.51 - .392 (pH) (14)
Since the stripper supernatant stream is high in phosphorus content (30-80 mg
P/l) and low in volume (generally 5 to 15% of the wastewater flow), the Pho-
Strip process requires only a fraction of the lime which would otherwise be
required if phosphorus were removed by direct addition of lime to the waste-
water.
Because the supernatant stream does have a higher phosphorus content,
a greater fraction of the lime added is consumed in the phosphate precipita-
tion reactions than when lime is added to the raw wastewater. The chemical
85
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sludge produced has a higher fraction of phosphorus, thus significantly reduc-
ing the quantity of sludge produced. Further reductions in sludge production
are achieved by maintaining a relatively low pH level for, precipitation
(8.5 SpH S 9.0). M these pH's, comparatively little calcium carbonate is
precipitated and almost no magnesium hydroxide is formed. The sludge pro-
duced is largely calcium phosphate precipitates.
The chemistry of phosphorus precipitation is very complex. For the
sake of simplicity, it is assumed that calcium ion reacts with the HPO/j"2
phosphorus species to form calcium hydroxyapatite according to equation (15).
(34)
3HPO4~2 + 5Ca+2 + 4OH"1 -*• Ca5 (OH) (PO4)3 + 3H2O (15.)
The solubility of this precipitate is so low that at pH levels as low as
8.5 soluble phosphorus levels of much less than 1 mg/1 are achievable.
Equation (14) predicts higher phosphorus levels than that obtained from the
solubility of calcium hydroxyapatite due to the inaccuracies of assuming that
the calcium phosphate species in equation (15) is the only product of phosphate
precipitation. It is likely that both octacalcium phosphate and tricalcium
phosphate are formed preferentially as the initial precipitates. (35) This is
possible,even though these are more soluble products, because the kinetics of
formation of these materials is much faster than that of the formation of calcium
hydroxyapatite. However, as time progresses after the initial precipitate is
formed, these more soluble species are converted to the hydroxyapatite form.
(36) Therefore, it can be assumed that the hydroxyapatite form is the final end
product of calcium phosphate precipitation. The rate of this conversion is
dependent on pH, temperature, and the presence of calcium hydroxyapatite
seed crystals. (37)
The quantity of lime required to achieve a given pH level for calcium
phosphate precipitation is a function of the wastewater alkalinity. Table 21
summarizes data taken at a number of locations to determine the lime require-
ments of the PhoStrip process. This data is plotted in Figure 25 along with
the curve recommended in the EPA Process Design Manual for Phosphorus Re-
moval. The reason for the variance between the EPA curve and the data pre-
sented in Table 21 is the lime dissolution efficiency. The data points to the
right of the line were taken from a system which was not designed to pre-
cipitate phosphorus with high lime utilization as a goal. The scatter in the
bench scale data is largely due to experimental error. This data does indicate
good agreement with the correlation recommended by the EPA and thus this
correlation should be used to determine the lime dose for the stripper super-
natant from the PhoStrip process.
86
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TABLE 21. SUMMARY OF
LIME DOSAGE REQUIREMENT STUDIES
OF THE STRIPPER SUPERNATANT
Location
Tonawanda, N.Y.
(Pilot Scale)
Adrian, Mich.
(Bench Scale)
Brockton, Mass.
(Bench Scale)
Texas City, Texas
(Bench Scale)
Phase
or
Test
I
II
III
IV
V
VI
1
2
3
4
5
1
2
1
2
Alkalinity*
mg CaCO3/l
310
310
325
340
370
380
210
210
215
215
235
165
165
350
350
PH
Initial
7.0
6.7
7.0
7.1
7.0
6.2
6.9
6.9
6.7
6.7
6.9
7.2
7.2
7.2
7.2
Final
9.1
10.5
9.6
10.2
10.1
9.2
9.0
9.5
9.1
9.5
9.1
9.3
9.7
9.0
9.5
Lime Dosage
mg CaO/1
225
380
255
330
424
312
93
166
141
150
133
64
95
123
180
* Sum of carbonate plus phosphate alkalinity
87
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00
00
12 -
QL 10 -
2
U-
9 -
8-
E.P.A, DESIGN MANUAL
D
D
0.2 0.3 0.4 0.5 0.60.7 1.0
CaQ/ALKALINITY
D PILOT PLANT
O BENCH SCALE
2.0 3,0 4.0
Figure 25. Lime requirements to achieve a given pH level.
-------
As with the lime dosage, the amount of sludge produced via precipita-
tion depends on the ability to efficiently dissolve lime. Sludge production
data obtained for the bench scale studies performed at Adrian, Michigan and
Texas City, Texas are presented in Table 22. This data demonstrates the
relationship between sludge production, pH, and phosphorus level. Generally,
an increase in either pH or phosphorus level will increase sludge production
per volume of supernatant. An increase in pH increases sludge production
mainly due to the formation of greater quantities of calcium carbonate and
magnesium hydroxide. Consequently, the phosphorus content of sludges pro-
duced at increasing pH levels is lowered. Increasing the phosphorus level
in the supernatant yields higher sludge production rates per unit volume, at a
constant pH, due to increased calcium phosphate precipitation products.
Thus, the phosphorus content of the waste sludge increases. For a given
mass of phosphorus to be precipitated, increased supernatant phosphorus
levels decrease chemical sludge production.
Figure 26 presents a comparison between the sludge production quanti-
ties obtained in the tests shown in Table 22 and those obtained through the
use of the method proposed in the EPA Process Design Manual on Phosphorus
Removal. (34) This comparison indicates that the calculational method is a
good approximation of the data. At pH levels greater than 10.0, the calcu-
lated and observed results agree quite well. At a pHof -^ 9.5, the calculated
values were approximately 8% lower than the measured values while at a pH
of ^9.0, the measured values were 15% higher than those obtained from
the calculations.
As discussed earlier, the precipitation portion of the PhoStrip process
should be operated at pH #9.0 to minimize lime requirements and chemical
sludge production. In order to obtain the proper sludge production quantities,
it is recommended that the method presented in the EPA Design Manual for
Phosphorus Removal (34) be employed with a 15% correction factor to account
for the inaccuracies that appear at a pH level of 9.0.
Table 23 summarizes the results of filter leaf studies run to determine
the filterability of the chemical sludge from the PhoStrip process. The sludge
for this study was obtained from a reactor clarifier system which was used to
precipitate the supernatant from a PhoStrip system operating on Tonawanda,
N.Y. wastewater. The sludge concentration obtained from the reactor clari-
fier and used in these tests ranged in TSS levels between 7 and 12%. The
solids concentration obtainable from full scale systems will depend on opera-
tional characteristics of the unit designed, but should range between 3 and
12%.
The results in Table 23 indicate that a vacuum filter can be used to
produce a 35% solids cake at filter loadings between approximately 8 and
16 IbsAr/ft2. These loadings were achieved without the use of chemical
89
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TABLE 22. CHEMICAL SLUDGE PRODUCTION
FROM STRIPPER SUPERNATANT
Phase
or
Location Test
Tonawanda, N.Y.
(Pilot Scale)
Adrian, Mich.
Texas City, Texas
I
II
III
IV
V
VI
1
2
3
4
5
1
2
Phosphorus
pH Removed
Final mg/1
9.1
10.5
9.6
10.2
10.1
9.2
9.0
9.5
9.1
9.5
9.1
9.0
9.5
18
35
36
41
57
75
36
36
38
38
48
26
28
Sludge Ca5(PO4)3OH*
Produced Content
mg/1 Supernatant %
380
600
530
710
650
560
240
320
310
340
350
210
320
27
31
36
31
47
72
80
61
66
60
83
67
48
* calculated from phosphorus removed
90
-------
2
O
K
O
D
Q
UJH
CD<
OZ
800
700-
600-
500-
400-
QCO
UJ.
200-
100-
A
E.P.A. DESIGN MANUAL
A pH > 10.0
O pH~ 9.5
D pH •* 9.0
00 200 300 400 500 600 700
MEASURED SLUDGE PRODUCTION
(mg/i SUPERNATANT)
Figure 26. Comparison of calculated^34' and measured sludge production.
91
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TABLE 23. FILTER LEAF TEST RESULT
OF CALCIUM PHOSPHATE SLUDGE
FORMED FROM STRIPPER SUPERNATANT
TS.S
Test Sludge
# %
1 11.5
2 11.5
3 11.5
4 11.5
5 11.5
6' 11.5
7 11.5
8 7.3
9 7.3
10 7.3
Form
Time
sec.
30
45
45
45
60
30
45
30
45
45
Dry
Time
sec.
50
75
105
135
100
100
105
50
75
75
Cake
Solids
%
i
33.9
34.5
35.4
36.3
35.5
37.2
35.9
32.5
32.8
32.7
TSS
Filtrate
mg/1
98
51
39
159
86
117
99
52
43
30
Loading
Rate
lb/hr/ft2*
15.9
11.9
9.4
7.8
10.3
9.2
12.3
9.5
7.9
8.9
Filter Cloth: Eimco NY529F
pH of quick mix tank = 9.1
*x 4.88 = kg/hr/m2
92
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conditioners. The filtrate produced in these tests were very low in suspended
solids indicating an average solids capture in excess of 99%. As with most
sludges, the loading capacity of the vacuum filter increases with increased
suspended solids levels in the sludge to be dewatered.
93
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REFERENCES
1. Process Design Manual for Phosphorus Removal. 1976. U. S. Environ-
mental Protection Agency Technology Transfer.
2. Ernst, P. 1888. Z. Hyg. IV, 25.
3. Babes, V. 1889. Z. Hyg. V, 173.
4. Grimme, A. 1902. Cbl. Bakt., Abt. I, Orig., XXXII, 191.
5. Meyer, A. 1904. Bot. Z., Abt. I, LXII, 113.
6., Zikes, H. 1922. Cbl. Bakt., Abt. II, LVII, 21.
7. Duguid, H. P. 1948. J. of Pathology and Bacteriology, LX, 265.
8. Kornberg, A., S. R. Kornberg, and E. S. Simms. 1956. Metaphosphate
Synthesis by an Enzyme from Escherichia Coli. Biochem. Biophys.
Acta 26:215-227.
9. Srinath, E. G., C. A. Sastry, and S. C. Pillai, 1959. Rapid Removal
of Phosphorus from Sewage by Activated Sludge. Experientia 15, 339.
10. Feng, T. H. 1962. Phosphorus and the Activated Sludge Process.
Water and Sewage Works. 109, 431.
11. Sekikawa, Y., S. Nishikawa, M. Okazaki, and K. Kato. 1966.
Release of Soluble Orthophosphate in Activated Sludge Process.
J. WPCF. 38, 3, 364.
12. Levin, G. V. 1966. U. S. Patent No. 3,236,766.
13. Levin, G. V., G. J. Topol, and A. G. Tarnay. 1975. Operation of
Full-Scale Biological Phosphorus Removal Plant, J. WPCF. 47, 3, 577.
14. Matsch, L. C. and R. F. Drnevich. 1977. U. S. Patent No.
4,042,493.
94
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15. Drnevich, R.F. and L. M. LaClair, 1976. New System Cuts Phosphorus
for Less Cost. Water and Wastes Engineering. 104
16. Campbell, T. L., J. M. Reece, and T. J. Murphy. 1977. Presented at
the New England Water Pollution Control Association Annual Meeting.
Whitefield, N.H., June 13-14.
17. Fuhs, G. W. and Min Chen, 1974. Microbiological Basis of Phosphate
Removal in the Activated Sludge Process for the Treatment of Wastewater.
Presented at the XIX Congress of the International Society for Theoretical
and Applied Limnology, Winnepeg, Canada.
18. Russ, C. 1975. Microbial Enhancement of Phosphorus Removal in Sludge
Sewage Systems. PhD Dissertation, Microbiology Department, Univer-
sity of Arizona.
19. Harold, F. M. 1966. Inorganic Poly phosphates in Biology: Structure,
Metabolism, and Function. Bacteriological Reviews, 30, 4; 772.
20. Kornberg, S. R. 1957. Adenosine Triphosphate Synthesis from Poly-
phosphate by an Enzyme from Escherichia Coli. Biochimia et Biophysica
Acta. 26:294.
21. Butler, L. 1977. A Suggested Approach to ATP Regeneration for Enzyme
Technology Applications. Biotechnology and Bioengineering 19:591.
22. Fox, J. L. 1977. Pyrophosphate Drives Biochemical Reactions. Chemical
and Engineering News, 22 (April 25).
23. Heffley, P. D. 1977. Phosphate Release Studies. Memorandum to R.F.
Drnevich, Union Carbide Corporation internal communication.
24. Russ, C. 1977. Personal communication. The Pennsylvania State Univ.
25. Gould, M. S. 1976. Personal communication. Union Carbide Corp.
26. Levin, G. V. 1974. Personal communication. Biospherics, Inc.
27. Sheridan, D. 1977. Personal communication. The Pennsylvania State
University.
28. Harold, F. M. 1962. Depletion and Replenishment of the Inorganic
Polyphosphate Pool in Neurospora crassa. J. Bacteriol. 83: 1047.
95
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29. Dick, R. I. 1970. Role of Activated Sludge Final Settling Tanks. Journal
Sanitary Engineering Division, American Society of Civil Engineers. 96,
SA2: 423.
30. Dick, R. I. and K. W. Young. 1972. Analysis of Thickening Performance
of Final Settling Tanks. 27th Annual Purdue Industrial Waste Conference.
Lafayette, Indiana.
31. Peirano, L. E. 1977. Low Cost Phosphorus Removal at Reno/Sparks,
Nevada. J. WPCF, 49, 4; 568.
32. EPA Methods for Chemical Analyses of Water and Wastes, 1974. U. S.
Environmental Protection Agency Technology Transfer.
33. Peirano, L. E., 1975. Personal communication.
34. Process Design Manual for Phosphorus Removal. 1976 U. S. Environ-
mental Protection Agency. Office of Technology Transfer, Washington,
D. C.
35. Zoltek, J. Jr., 1976. Identification of Orthophosphate Solids Formed
by Lime Preci pitation. JWPCF 48, : 17 9.
36. Nancollas, G. H. and B. Tomazic. 1974. Growth of Calcium Phosphate
on Hydroxyapatite Crystals, Effect of Supersaturation and Ionic Medium.
J. Phys. Chem. 78:2218.
37. Nancollas, G. H. and M. S. Mohan. 1970. The Growth of Hydroxy-
apatite Crystals. Archs, oral Bio 1. 15:731.
96
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APPENDIX
(ECONOMIC EVALUATIONS)
These two case studies are verbatim excerpts from design reports.
They have been included with the permission of the consulting firms involved
and are for illustrative purposes only.
ADRIAN, MICHIGAN
The following has been extracted from "Professional Judgment Finding
on 'PhoStrip1 Phosphorus Removal System, Lenawee County Drain Commissioner
for the City of Adrian, Michigan, Wastewater System Improvements, C262449"
prepared by McNamee, Porter and Seeley, Consulting Engineers, Ann Arbor,
Michigan, June 1977. This report was submitted to and approved by the Bureau
of Environmental Protection, Michigan Department of Natural Resources.
Background
The City of Adrian is currently served by a 5 mgd activated sludge
plant which discharges to the South Branch of the River Raisin. The secondary
plant has been in operation since 1938 with additions made in 1950 and 1967.
At present, flows during peak months average near the design capacity. An
expansion of the plant is proposed to increase capacity for inclusion of domes-
tic and industrial flows from Adrian and Madison Township surrounding the
City. Included in the expansion is the addition of the capability of removing
phosphorus in compliance with proposed final effluent discharge requirements.
In conjunction with the Step 2 design for expansion of the Adrian
Wastewater Treatment Plant an investigation was made of available processes
for phosphorus removal. Because of potential operation and maintenance cost
savings and successful test operation at other locations, a pilot-scale opera-
tions study was begun in July 1976 to evaluate the applicability of the PhoStrip
process for phosphorus removal. The results of the pilot study were presented
to the Michigan DNR in December 1976 and clearly showed that the process
effectively removed phosphorus from the Adrian wastewater in excess of the
requirements of the proposed NPDES Permit.
97
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General Process Description
The PhoStrip process utilizes activated sludge microorganisms to con-
centrate phosphorus from the wastewater flow stream into a relatively small
substream from which removal by chemical precipitation is relatively inexpen-
sive. The process takes advantage of the biological phenomena of "luxury
uptake" and "anaerobiosis" for release of phosphorus.
A holding tank (stripping tank) is used to detain a portion of the return
activated sludge (RAS) under anaerobic conditions for phosphorus release and
to separate a clear phosphorus-rich liquor (supernatant) from the RAS flow
stream. The high phosphorus concentration supernatant is transferred to a
rapid mix tank where it is mixed with a lime slurry. The resulting mixture of
supernatant, lime slurry and precipitated solids is then transferred to the
primary clarifiers for separation by gravity sedimentation of the phosphorus
precipitate.
The microorganisms take up phosphorus in the aeration tank and then
are induced to release phosphorus while detained under anaerobic conditions
in the stripping tank. The compacted activated sludge (anaerobic RAS) in the
bottom of the stripping tank contains phosphorus deficient microorganisms and
phosphorus rich liquor. The anaerobic RAS is returned to the aeration tank
where the phosphorus uptake cycle is repeated. Anaerobic RAS is also re-
cycled through the stripping tank by blending with the influent return activated
sludge (aerobic RAS) from the 1st stage sedimentation tank in order to convey
phosphorus-rich liquor to the surface of the stripping tank. The major differ-
ence between the PhoStrip process and other attempts to use biological pro-
cesses for phosphorus removal is the use of a separate phosphorus stripping
tank where phosphorus release is induced and controlled. Also, only a frac-
tion of the RAS is diverted to the stripper (approximately 10-15% of the total
design flow).
Justification for Use
The proposed Adrian WWTP design is for a two-stage activated sludge
system. The first stage will be used for carbonaceous removal and the second
stage will convert ammonia to nitrate. The PhoStrip process will be operated
in conjunction with the first stage aeration system. The main advantage of the
PhoStrip system is dosing only 10-15% of the sewage flow with chemicals as
compared to the conventional method of chemical treatment which uses addition
of chemical to the entire flow of sewage. Most of the operating expenses of
phosphorus removal is the chemical cost and the PhoStrip system significantly
reduces this cost. This will be shown in the cost-effective analysis in the
following section.
Also, the PhoStrip process produces less solid waste which is another
98
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major cost savings, since solid wastes directly affect sludge handling and
disposal operations.
Another advantage to the PhoStrip system is that it is less affected by
shock load, as would be expected, because of the offstream reservoir of
activated sludge provided by the stripping tank. This is especially important
in Adrian's case because of the history of industrial pollutant shock loads that
have been experienced in the raw sewage flow.
The pilot plant test data on the typical Adrian domestic wastewater
conclusively demonstrated the satisfactory performance of the PhoStrip process
for achieving greater than 90% removal of phosphorus.
The use of lime addition for phosphorus removal also enhances the pro-
cess. The cost per ton of lime versus the traditional chemicals is less. Also,
the nitrification stage of the plant will require,pH adjustment to achieve com-
plete nitrification due to low influent alkalinity. With a lime handling facility
already provided for in the PhoStrip process, the system can also be used for
the pH control needed throughout the plant. The lime-phosphorus sludge which
will be transferred to the primary sedimentation tank will enhance the settle-
ability of the raw sludge, thus increasing the removal efficiency of the tanks.
Cost Effective Analysis
An economic evaluation was made comparing PhoStrip against the tradi-
tional chemical addition methods using ferric chloride and alum. The cost-
effective analysis included initial installment cost and total annual costs
which includes capital cost amortized over 20 years at 6-1/8% interest;
chemical cost; operating labor; maintenance and repair costs; and sludge dis-
posal costs.
The PhoStrip costs were based on treatment of 15% of the maximum
plant flow of 7 mgd, or 1.0 mgd. The cost of the two traditional chemical
processes were based on total plant flow of 7 mgd. The bench scale lime
dosage test conducted during the pilot plant operation established a lime
dosage of 250 mg/1 to produce the desired treatment. The dosage required for
treatment with the traditional chemicals were: 90 mg/1 of ferric chloride and
135 mg/1 of alum.
The estimated total annual cost of increasing the capacity of the exist-
ing plant and adding the capability for phosphorus removal are: $85,565 per
year using the PhoStrip process; $129,163 per year using the Ferric Chloride
process; and $136,183 per year using the alum process.
99
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Table EE-1
Cost Comparison Between
PhoStrip and Chemical Addition for Phosphorus Removal
at Adrian, Michigan
Design Flow = 7 mgd
Influent P = 10 mgd
Effluent P = 1 mg/1
Item PhoStrip Ferric Chloride Alum
A. Installed Investment1 $520,000 $ 60,000 $ 65,000
B. Annual Costs
1. Amortized Investment2(Ax 0.08897) 46,265 5,338 5,783
2. Chemical Costs
a. Lime3 20,000
b. Ferric Chloride4 105,500
c. Alum5 115,000
3. Operating Labor, Maintenance
& Repair 8,000 3,000 3,500
4. Sludge Disposal Cost O&M @565 T/yr @765 T/yr (§770 T/yr
a. Anaerobic Digestion at $5/ton 2,800 3,825 3,850
b. Transport of Liquid Sludge by
Tank Truck at $15/Ton 8,500 11,500 11,550
TOTAL ANNUAL COST $85,565 $129,163 $136,183
$/mg $33.50 $50.55 $53.30
See Table EE-2 for cost breakdown.
2
Assumes a 20-year equipment life and 6-1/8% capital cost.
3
Based on a 250 mg/1 lime dosage, 15% Qt supernate flow, and a lime
cost of $50/ton delivered.
4
Based on a 90 mg/1 FeClg dosage, 7 mgd flow, and a FeCl3 cost of
$110/ton delivered.
Based on a 135 mg/1 alum dosage, 7 mgd flow, and an alum cost of
$80/ton delivered.
10.Q
-------
Table EE-2
PhoStrip Cost Comparison
Equipment Cost (PhoStrip) Cost
I. Stripper Tank
a. Concrete 65-ft. dia. at 20-ft. SWD $150,000
b. Mechanism & Warranty (supplied by Union Carbide) 245,000
2. Lime-Mix Tank
a. Concrete 9-sq. ft. at 12-ft. SWD 57,500
b. Mixer 2,500
3. Pumps
a. Stripper supernatant Pumps 2,000
b- Anaerobic RAS Pumps 2,000
c. Stripper Waste Pumps 1,000
4. Lime Feed Equipment* (50 ton Bin,Feeder,Slaker) 60,000
Total Installed Cost $520,000
\
* Cost taken from EPA Manual "Phosphorus Removal", p. 10-32
2520<1977)
ENR = ~£ = 1.53
1643(1971)
Equipment Cost (Ferric Chloride)
1. Bulk Storage 2/8000 gal. tanks $25,000
2. Pumps
Transfer 15,000
Feed
3. Dilution and Feed Tanks, Agitation, Piping 20,000
Total Installed Cost $60,000
Equipment Cost (Alum)
1. Bulk Storage 4/8000 gal. tanks $50,000
2. Pumps
Transfer ^ 15,000
Feed
Metering
Total Installed Cost $65,000
101
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The savings in total annual costs through the use of the PhoStrip pro-
cess amount to approximately $44,000 per year, chemical costs showing the
largest cost savings. The cost per million gallons of the traditional chemical
addition is approximately twice as much as the PhoStrip process. The PhoStrip
process requires a higher initial investment (approximately $460,000 or
$40,000 per year amortized cost difference).
SOUTHTOWNS, NEW YORK
The following was extracted from an addendum to the Facilities Report
for the Southtowns Sewage Treatment Agency, Erie County, New York, pre-
pared by McPhee, Smith, Rosenstein Engineers, Montvale, New Jersey. This
report was submitted to and approved by the New York State Department of
Environmental Conservation.
Phosphate Removal
1) General
As previously described, the present plans call for the removal
of phosphorus from the wastewater by post precipitation of the biologically
treated effluent, followed by filtration. The cost of alum to remove the
phosphorus will amount to a sizable portion of the operating budget of the
facilities. The PhoStrip process can accomplish the phosphorus removals at
a lower capital and operating cost.
Messrs. Levin, Topol, Tarnay and Samworth reported pilot plant
work on this new process for the removal of phosphates. The PhoStrip process
is a unique system that accomplished phosphorus removal by dosing only a
small fraction of the sewage flow with chemicals instead of dosing the total
flow.
The PhoStrip process is based on three characteristics experi-
enced in sewage treatment:
a) The activated sludge microorganisms in the mixed liquor of
an activated sludge process can be induced to take up soluble phosphorus.
This is known as "luxury uptake" since the quantity "taken up" is in excess
of the amount required for growth.
b) If the mixed liquor solids are denied oxygen and once all the
dissolved oxygen available is consumed, the microorganisms will release the
phosphorus previously taken up, and it will go back into solution.
102
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c) If the supernatant of the mixed liquor solids is treated with
lime similar to the cold lime softening of water, the soluble P can be precipi-
tated and removed from the process.
The PhoStrip process accomplishes the removal of phosphorus by
utilizing the above characteristics in the following manner (see Figure EE-1):
a) A fraction of the sludge from the bioclarifier underflow is
conveyed to an anaerobic phosphate stripper. The remaining fraction is re-
turned to the oxygen reactors. The dilution time in this stripper is set so that
the contents will consume all the dissolved oxygen present and pass into an
anaerobic state. As the microorganisms give up the soluble P they had taken
up, they are washed in the stripper by an upflow of low P effluent water from
the phosphorus precipitator (reactor clarifier). An alternate source of the
elutriation stream will be the effluent from the biological clarifier.
b) The phosphorus-enriched stripper supernatant flows to a
solids-contact clarifier where lime is added to precipitate the phosphorus. As
stated previously, the effluent from the clarifier is returned as an elutriation
stream for the stripper. The sludge from the clarifier will be pumped to a
holding tank prior to dewatering on a vacuum filter.
As can be noted from the above description, only a small
percentage of the total plant flow has to be treated to remove the necessary
amount of phosphorus. The volume of the supernatant stream will be approxi-
mately 10% of the total plant flow, thereby reducing the size of the treatment
units and the quantity and cost of the chemicals removed.
c) The phosphorus stripped sludge is withdrawn from the bottom
of the stripper and returned to the oxygen reactors. The sludge has a rela-
tively large capacity to pick up soluble phosphorus from the wastewater.
2) Pilot Plant Data
Laboratory pilot plant work was done by Levin et al and was
reported in the October 1974 Journal, Water Pollution Control Federation. This
report concluded:
a) that the new process would remove 90% of the total phos-
phorus present in the wastewater;
b) by the addition of the filtration step, the removal could be
increased to 95%;
c) the method was compatible with the conventional activated
sludge process;
103
-------
Influent From _
Pump
Alternate
Pump
Station^
k
OXYGEN
REACTORS
BIO-CL/
Recqlce
Feed to _
Station
• *
REA
CLARI
s-
3hosphorus
Lime
» Phosphor
Enriched
CTOR Supernal
FIERS 1 ^
Elutriation
i
sus
-e AN
e PHOS
STRIf
Stream ~"
Chemical
=»»6ludqe to
Disposal
\
\RIFIERS
OXIC
PHATE
DPER
Effluent To ,
Sand
]
Filters "
Alternate
Elutriation
Stream
f
LEGEND
Stripped Sludge
SEWAGE FLOW
Figure EE*-1. PhoStrip flow pattern.
-------
d) the sludge produced was less than produced if the entire
waste stream were treated with lime;
e) activated sludge process was improved; and
f) the method provided a reserve reservoir of mixed liquor
suspended solids.
The City of Reno, Nevada instituted a full-scale plant size
study. The work was begun in May 1974 and was reported in a paper given at
the 48th Annual Conference of the Water Pollution Control Federation on
October?, 1975. The paper concluded:
a) that in a 6 mgd plant scale test, 90% of the phosphorus
could be removed;
b) the process could be operated with relative ease;
c) a saving of $600,000 to $800,000 a year could be realized
in the O&M of a 40 mgd plant.
After Union Carbide purchased the PhoStrip process, they con-
tinued to test the process and improve on it. Their work has improved the
process as far as reducing its capital costs and operating costs are concerned.
They ran a pilot plant at their Tonawanda, N.Y. facilities, and Table EE-3
summarizes the data from the Tonawanda pilot plant for five different phases.
The phases tried are as follows:
I) No elutriation of the sludge in the anaerobic stripper.
II, III, IV) Effluent from a primary clarifier was recycled as an
elutriant.
V) The effluent from a solid contact clarifier was recycled as
an elutriant.
The table shows that the average total P in the effluent for all
test phases was 1.0 mg/1 or less.
Additional pilot plant work was done at Texas City, Texas. A
10 gph pilot plant, consisting of primary clarifier, aeration basins, secondary
clarifier and anaerobic stripper was used. Table EE-4 shows the results of
this plant for a 14-day steady state phase. The average total P in the efflu-
ent was measured as 0.7 mg/1 and the maximum of 1.5 mg/1. Since the plant
did not have a continuous lime precipitation phase, the results are based on
jar tests of the effluent.
105
-------
Table EE-3
PhoStrip System Pilot Plant Testing
II
III
IV
V
Feed Rate, GPM
% of total flow as:
Sludge recycle direct to aeration*
Sludge feed to stripper
Supernatant from stripper
Temperature, F
pH, mixed liquor
pH, stripper supernatant
MLSS, mg/1
MLVSS, mg/1
F/M (organic loading),
Ib. BOD5app/day/lb. MLVSS
Retention time-aeration, hr.
Retention time-stripper, hr.
Phosphorus concentration, mg/1
Influent
Effluent (total P)
Effluent (soluble P)
Stripper supernatant
Stripper underflow (filtered)
Clarifier overflow rate,
Lb.P/lb. MLVSS
Effluent quality
E3S,mg/l
EVSS, mg/1
BOD, influent, mg/1
BOD, total effluent, mg/1
Duration of test, days
12.1
10.0
13.0
15.0
15.0
24.8
13.2
56
7.0
6.7
2930
2320
0.51
1.6
9.9
33.5
19.3
57
6.7
7.0
4820
3600
0.27
2.5
5.4
23.7
14.9
61.2
6.7
7.1
3620
2710
0.60
1.9
5.9
20.7
19.4
9.1
64.4
6.7
7.0
5190
3750
0.38
1.7
6.1
14.0
20.0
11.9
72
6.4
6.3
4750
3490
0.44
1.7
6.4
5.3
0.9
0.7
27.0
59.0
580
0.027
6.8
0.4
0.2
38.0
22.0
480
0.024
6.6
0.5
0.3
43.0
34.0
630
0.028
7.5
0.5
0.3
53.5
36.5
725
0.033
10.5
0.9
0.4
70.5
46.0
725
0.040
10
9
78
10
7
7
96
8
10
6
139
9
7
5
100
10
10
8
110
13
10
12
29
29
37
All sludge passed through the stripper during test Phase I, II and III before recycle to aeration.
-------
Table EE-4
PhoStrip Pilot Plant - Texas City, Texas
Phosphorus Balance Data - Steady State Phase
Date
3-17-76
3-18-76
3-19-76
3-20-76-
H 3-21-76
-J 3-22-76
3-23-76
3-24-76
3-25-76
3-26-76
3-27-76
3-28-76
3-29-76
3-30-76
AVERAGE
MAXIMUM
MINIMUM
INFLUENT
Total P Ortho
mg/1 mg/1
7.6
8.0
9.0
8.4
6.4
4.6
-
n.o
8.3
7.6
7.6
-
9.1
6.8
7.9
11.0
4.6
7.0
6.2
7.0
5.2
3.8
4.2
6.6
6.0
5.1
6.0
5.7
6.6
6.2
5.4
5.8
7.0
3.8
EFFLUENT
Total P Ortho P
mg/1 mg/1
0.4
0.8
1.4
0.2
0.5
0.4
0.5
1.5
0.6
0.9
0.2
0.6
0.6
0.6
0.7
1.5
0.2
0.4
0.3
0.8
0.1
0.0
0.0
0.5
0.5
0.2
0.7
0.2
0.2
0.4
0.2
0.3
0.8
0.0
STRIPPER
SUPERNATE
Total P Ortho P
mg/1 mg/1
144
112
36
29
27.5
29.0
53.0
45
30
61.5
34
18
24
22
47.5
144
18
52
50
42.5
34.0
33.0
34.0
38.5
37.5
23
35
31
28.5
28.5
25
35.9
52
23
STRIPPER
FILTERED STRIPPER WASTE UNDERFLOW
AERATION EFFLUENT INF SLUDGE Filtered
Total P Ortho P Total P Total P Total P Ortho P
mg/1 mg/1 mg/1 mg/1 mg/1 mg/1
0.2
0.2
0.1
5.8
3.8
0.4
0.2
1.8
0.6
0.9
-
-
0.9
0.1
1.3
3.8
0.1
0.1
0.1
0.1
6.2
4.0
0.0
0.4
1.2
0.4
0.8
-
3.7
0.3
0.1
1.3
6.2
0.0
520
332
264
288
364
280
304
352
280
264
312
200
388
408
325
520
200
364
320
-
124
320
364
140
312
220
192
432
-
388
-
289
432
124
552
288
288
332
312
332
264
296
256
232
296
388
272
364
319
552
232
25
22
18.5
42.5
48.0
40.0
27.0
22.5
18.0
13.5
61.0
70
40
44.5
35.2
70
13.5
-------
A nine-week pilot study of waste from the Hamburg Master
District has just been concluded. The average effluent concentration of solu-
ble P in the effluent was 0.1 mg/1, well below the design value of 0.5 mg/1.
The average total P in the effluent was 1.4 mg/1. These effluent concentra-
tions are following clarification. There weren't any filters in the pilot plant.
The effluent solids averaged 58 mg/1, but this was because of the small scale
of the pilot plant clarifier. In a full scale operation, the effluent concentra-
tion of total P and suspended solids should be lower. In addition, the South-
towns treatment plant will have filtration following clarification, which will
result in lower effluent concentrations of P and SS.
3) Cost Effective Analysis
An economic analysis of three (3) design alternates follows. The
first alternate is the present design which consists of using aluminum salts
for phosphate removal, incineration of a combination of chemical and waste
activated sludge and trucking the ash to a landfill. Alternate II is the PhoStrip
process which substitutes quicklime for alum. For this alternate the PhoStrip
sludge would be dewatered separately, the waste activated sludge would be
incinerated and a combination of PhoStrip sludge and incinerator ash would be
hauled to a landfill. The third alternate consists of the incineration of the
PhoStrip sludges along with waste activated sludges. The ash would then be
hauled to a landfill. In addition, the on-site disposal of the residue for the
three alternates was studied. These are referred to as Alternates IA, IIA, and
IIIA.
Tables EE-5 and EE-6 present the annual and operating costs for
the initial and the 20th year of operation. The cost for dumping sludge in a
segregated landfill at the Lancaster site has been assumed to be $10.60/ton.
The calculations in Tables EE-5 and EE-6 are based on the assumption that a
15 cubic yard truck will be used to haul sludge to Lancaster. Chemical costs
of $30/ton for quicklime, $95/ton for A12C>3 and $130/ton for ferric chloride
have been assumed. Fuel oil is assumed to cost $0.30/gallon.
Table EE-7 summarizes the capital costs associated with the six
alternates. The capital cost of the PhoStrip equipment is approximately
$2,100,000 versus $2,650,000 for the present system. The capital cost for
the PhoStrip system with the sludge being incinerated will be approximately
$2,200,000. The engineering costs to revise the plans and specifications to
incorporate the PhoStrip process will cost $210,000. It has been assumed
that this design will delay the project a maximum of four (4) months until all
Federal and State approvals are obtained.
The outfall sewer will be bid on time. The escalation in the
other contracts will be 6%. It is assumed that the contractor costs will
escalate approximately ($28,000,000) (.06) 4/12 = $560,000. If the residue
108
-------
Table EE-5
Annual Costs - Initial Year
o
vo
Ash or Ash & Sludge
#/d
#/CF
CY/day
Trips/week
Trucking Cost ($/yr)
Depreciation
Maintenance
Gas/Oil
Labor $16,000/yr.
Sub Total
Annual Cost
Al2O3 or CaO
FeCl3
CaO
Add'tl Fuel Oil/1
Landfill Charge
Alt
Alum
To
Lancaster
6,108
150
1.5
1
4,000
1,000
1,300
1.600
7,900
. I
Sludge
On
Site
6,108
150
1.5
1
4,000
1,000
100
200
5,300
Alt. II
PhoStrip
To
On
Lancaster Site
12,353 12
105
4.4
2
4,000 4
1,000 1
2,600
3,200
10,800 5
,353
105
4.4
2
,000
,000
200
400
,600
Alt. Ill
PhoStrlp/Incin
To
Lancaster
6,444 6
150
1.6
1
4,000 4
1,000 1
1,300
1.600
7,900 5
*
On
Site
,444
150
1.6
1
,000
,000
100
200
,300
Jinerator
Sub Total
Sub Total
TOTAL
39,182
31,505
,3,635
-
11,815
86,137
7,900
$94,037
39,182
31,505
3,635
-
-
74,322
5,300
$79,622
8,020
26,139
3,016
-
23,896
61,071
10,800
$71,871
8,020
26,139
3,016
-
-
37,175
5,600
$42,775
8,020
33,240
3,835
2,208
12,465
59,768
7,900
$67,668
8,020
33,240
3,835
2,208
-
47,303
5,300
$52,603
-------
Table EE-6
Annual Costs - Year-20
Ash or Ash & Sludge
#/d
t/CF
CY/day
Trips/week
Trucking Cost ($/yr)
Depreciation
Maintenance
Gas/Oil
Labor $16,000/yr
Sub Total
Annual Cost
Al£O3 or CaO
FeCl3
CaO
Add'tl Fuel Oil/Incinerator
Landfill Charge
Sub Total
Sub Total
TOTAL
Alt
Alum
To
Lancaster
13,783
150
3.4
2
4,000
1,000
2,600
3,200
10,800
. I
Sludge
On
Site
13,783
150
3.4
2
4,000
1,000
200
400
5,600
Alt II
PhoStrip
To On
Lancaster Site
27,873 27,873
105 105
9.8 9.8
5 5
4,000 4,000
1,000 1,000
6,500 500
8,000 1,000
19,500 6,500
Alt. Ill
PhoStrip/Incln.
To On
Lancaster Site
14,542 14,542
150 150
3.6 3.6
2 2
4,000 4,000
1,000 1,000
2,600 200
3,200 400
10,800 5,600
88,507
71,089
8,202
26,663
194,461
10,800
88,507
71,089
8,202
157,798
5.600
18,094
58,980
6,805
53,920
137,799
19,500
18,094
58,980
6,805
83,879
6,500
18,094
75,004
8,654
4,990
28.131
134,873
10,800
18,094
75,004
8,654
4,990
106,742
5, 600
$205,261 $173,398 $157,299 $90,379 $145,673 $112,342
-------
Table EE-7
Capital Costs
Alt. I
Alt. II
Construction Cost
Phosphorus Removal Sect.
Development of Landfill
at Site
Engineering Cost of
Revising Plans & Specs
Additional Demolition
Due to Landfill at Site
Inflation on Treatment
Plant, 4 mo. at 6%
- Salvage Value
TOTAL
To
Lancaster
On
Site
To
Lancaster
On
Site
Alt. Ill
To
Lancaster
On
Site
2,650,000 2,650,000 2,100,000 2,100,000 2,200,000 2,200,000
100,000
100,000
100,000
210,000 210,000 210,000 210,000
200,000 200,000 200,000 200,000 200,000 200,000
- - 560,000 560,000 560.000 560.000
$2,850,000 $2,950,000 $3,070,000$3,170,000 $3,170,000$3,270,000
265,000 265.000 210,000 210,000 220,000 220,000
$2,585,000 $2,685,000 $2,860,000$2,960,000 $2,950,000$3,050,000
-------
is to be disposed of on the existing site, it has been estimated that it will
cost $100,000 to develop a segregated landfill at the site. Erie County was
planning to demolish all the silos and buildings on the site, even those that
would not have been eligible for Federal and State aid. If the residue is dis-
posed of on the site, the additional demolition work that wasn't necessary in
order to build treatment facilities would not be necessary in order to develop
an on-site landfill. The estimated cost for this additional demolition
($200,000) will not be eligible for Federal and State aid.
A cost-effective analysis based on a 20-year planning period at
6-1/8% interest for the six (6) alternates is shown in Table EE-8.
4) Conclusions and Recommendations
A summary of the present worth of the six (6) alternates is given
below:
Alternate Present Worth
I $4,131,000
IA $3,990,000
II $4,041,000
IIA $3,649,000
III $4,051,000
IIIA $3,902,000
The cost-effective analysis for the 20-year period shows that
Alternate IIA, the PhoStrip process with the chemical sludge dewatered
separately and disposed of on the site along with the incinerator ash is the
most cost-effective method. It is our recommendation that this process be
specified as the exclusive process for the Erie County/Southtowns Wastewater
Treatment Plant. We recommend that the rapid sand filters as planned for the
original design be used to assure that the phosphorus in the effluent is con-
sistently less than 1.0 mg/1 as P. The insoluble phosphates in the bioclarifier
effluent, along with the phosphorus tied up in the suspended solids, will be
removed by the sand filters.
112
-------
Table EE-8
Present Worth Analysis
ALTERNATE I - Alum Sludge to Lancaster
Present Worth of
Annual Costs = (94,037) (11.3549) = 1,067,780
(205,261-94.037) (85.93) = 477,873
20
Capital Costs = 2,585,000
Total Present Worth $4,130,653
SAY $4,131,000
ALTERNATE IA - Alum Sludge on Site Disposal
Present Worth of
Annual Costs = (79,622) (11.3549) = 904,099
(173.398-79.622) (85.39) = 400,376
20
Capital Costs = 2,685,000
Total Present Worth $3,989,475
SAY $3,990,000
ALTERNATE II - PhoStrip to Lancaster
Present Worth
of Annual Costs = (71,871) (11.3549) = 816,088
(157.299-71,871) (85.39) = 364,734
20
Capital Costs = 2,860,000
Total Present Worth $4,040,822
SAY $4,041,000
(Continued)
113
-------
Table EE-8
Present Worth Analysis
(Continued)
ALTERNATE IIA - PhoStrip on Site
Present Worth
of Annual Costs = (42,775) (11.3549) = 485,705
(90.379-42.775) (85.39) = 203,245
20
Capital Costs = 2.960,000
Total Present Worth $3, 648,950
SAY $3,649,000
ALTERNATE III - PhoStrip - Incinerator - to Lancaster
Present Worth
of Annual Costs = (67,668) (11.3549) = 768,363
(145.673-67.668) (85.39) = 333,042
20
Capital Costs = 2,950.000
Total Present Worth $4,051,405
SAY $4,051,000
ALTERNATE IIIA - PhoStrip - Incinerator - On Site Disposal
Present Worth
of Annual Costs = (52,603) (11.3549) = 597,301
(112,342-52.603) (85.39) = 255,055
20
Capital Costs = 3.050.000
Total Present Worth $3,902,356
SAY $3,902,000
114
-------
APPENDIX A
(RAW DATA SUMMARY)
English to SI Conversions
GPM x 6.3 x 10~5 = m3/s
in. x .0254 = m
(T eF - 32) x 0.555 = T °C
f\
GALx 3.785 x 10~3 = rir
MGD x 3785 - m3/D
(FT3/GAL) x 7.481 = m3/m3
115
-------
TABLE A-l. PHASE I OPERATING CONDITIONS FOR
PHOSTRIP PILOT PLANT - RENO/SPARKS. NEVADA
*
PLANT SLUDGE STRIPPER
INF RECIRCULATION INFLUENT
DATE
U-19-75
11-20-75
11-21-75
11-22-75
11-23-75
11-24-75
11-25-75
11-26-75
11-27-75
11-28-75
U-29-75
11-30-75
12-01-75
12-02-75
12-03-75
12-04-75
12-05-75
12-06-75
12-07-75
12-08-75
AVERAGE.
GPM
5.0
5.0
5.0
5.0
5.0
5.0
5.0
5.0
5.0
5.0
5.0
5.0
5.0
5.0
5.0
5.0
5.0
5.0
5.0
5.0
5.0
GPM
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.58
0.59
0.51
ZQ
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
12
12
10
GPM
1.25
1.25
1.25
1.25
1.25
1.25
1.25
1.25
1.25
1.25
1.25
1.25
1.25
1.25
1.25
1.25
1.25
1.25
1.24
1.25
1.25
*9
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
STRIPPER
UNDERFLOW
GPM *Q
0.5
0.5
0.5
0.5
0.5
0.51
0.78
0.80
0.77
0.78
0.77
0.77
0.78
0.78
0.78
0.78
0.65
0.48
0.49
0.52
0.65
10
10
10
10
10
10
16
16
15
16
15
15
16
16
16
16
13
10
10
10
13
AER
£8
4.9
4.9
4.9
4.9
4.9
4.9
4.9
4.9
4.9
4.9
4.9
4.9
4.9
4.9
4.9
4.9
4.9
4.9
4.9
4.9
4.9
AVG
D.O.
V1
0.6
0.6
0.6
3.2
2.2
3.0
1.9
1.3
1.7
1.8
2.9
2.6
1.2
1.6
0.8
1.7
2.2
1.8
-
2.6
1.8
STRIPPER
BLANKET M.L.
HEIGHT STRIPPER TEMP
INCHES SRT RRS *F
46.5
43.5
42
36
42 .
41.5
38
33.5
36
42
49
48
50
50
55
51.5
56.5
57.5
64
56
46.9
10.2
9.6
9.3
7.9
9.3
9.0
5.4
4.6
5.2
5.9
7.0
6.9
7.1
7.1
7.8
7.3
9.6
13.2
14.4
11.9
8.0
59
60
60
59
60
61
61
61
62
60
57
60
61
60
61
62
63
61
59
60
60
MLSS
•g/1
1796
1388
1560
1340
1688
1208
1000
1114
1407
1654
1414
1596
1194
1430
1150
1550
1590
1510
700
1156
1372
MLVSS
««/l
1248
1228
1332
1204
1496
1120
880
894
1127
1301
1154
1380
1161
1150
-
1340
1480
1470
680
1108
1198
STRIPPER*
INFLUENT
RSS RVSS
mg/1 mg/1
6648
6468
6360
6360
7284
5590
5180
6510
7911
6800
7510
6790
6070
6960
6530
7020
7130
5090
4590
4780
6379
5664
5468
5404
5476
6192
4910
4472
5476
6677
5570
6120
5643
5336
5910
5880
6070
6270
4580
4010
4240
5469
STRIPPER
UNDERFLOW
RSS RVSS
«/l m«/l
17344
16020
14556
17164
15640
11810
10612
8064
9485
10850
10720
11032
9838
10790
11800
11639
11310
13170
11200
14660
12385
14696
13556
12360
14240
13064
10000
9056
6770
8011
9070
9030
9278
8618
9180
10370
3335
10820
11450
9660
12700
10263
WASTE
SLUDGE
GAL/DAY
150
150
150
112.5
131.3
150
112.5
75
18.8
50
75
82.5
20
18.8
67.5
47.5
60
35
50
55
81.2
CTi
* SECONDARY CLARIFIER UNDERFLOW
-------
TABLE A-2. PHASE I ORGANIC & SUSPENDED
SOLIDS REMOVALS FOR PHOSTRIP PILOT PLANT
RENO/SPARKS, NEVADA
DATE
11-19-75
11-20-75
11-21-75
11-22-75
11-23-75
11-24-75
11-25-75
11-26-75
11-27-75
11-28-75
11-29-75
11-30-75
12-01-75
12-02-75
12-03-75
12-04-75
12-05-75
12-06-75
12-07-75
12-08-75
COD,
INF
190
207
199
207
257
169
270
228
367
266
241
236
214
294
176
235
172
260
176
201
mg/1
EFF
108
58
50
99
91
25
34
42
25
38
21
59
38
46
34
34
29
25
34
50
TSS,
INF
203
121
106
138
230
146
128
116
198
81
130
104
95
132
96
116
63
143
93
73
mg/1
EFF
45
56
38
31
-
28
51
48
40
29
43
47
28
39
35
28
23
33
26
11
VSS,
INF
187
114
96
84
219
126
123
96
172
69
103
-
93
114
81
102
59
129
83
66
mg/1
EFF
40
50
38
-
-
17
45
42
37
23
35
43
18
35
24
25
15
24
16
7
AVERAGE 228 47 126 36 111 30
-------
TABLE A-3. PHASE I PHOSPHORUS BALANCE DATA
FOR PHOSTRIP PILOT PLANT - RENO/SPARKS, NEVADA
INFLUENT
DATE
11-19-75
11-20-75
11-21-75
11-22-75
11-23-75
11-24-75
11-25-75
11-26-75
11-27-75
£ 11-28-75
00 11-29-75
11-30-75
12-01-75
12-02-75
12-03-75
12-04-75
12-05-75
12-06-75
12-07-75
12-08-75
AVERAGE
MAXIMUM
MINIMUM
TOTAL P
rtg/1
5.5
6.1
6.6
6.4
7.0
6.2
8.6
8.2
9.5
7.8
8.3
8.2
9.2
10.1
6.7
8.8
7.9
9.3
9.6
9.7
8.0
10.1
5.5
ORTBO P
mg/1
3.7
6.1
5.3
4.4
5.0
4.5
7.0
6.6
6.6
6.5
5.9
7.2
8.6
9.4
5.1
7.2
5.7
6.8
8.4
8.2
6.4
9.4
3.7
EFFLUENT
TOTAL P
mg/1
1.9
2.1
2.3
1.0
2.5
3.3
4.7
4.6
4.3
4.4
2.8
4-4
4.9
5.7
4.2
3.7
3.2
2.8
4.0
3.8
3.5
5.7
1.0
ORTHO P
mg/1
.16
1.5
2.04
.64
2.64
3.48
4.8
3.85
4.5
4.4
1.95
4.1
4.7
5.5
4.5
3.1
2.7
2.65
3.2
3.2
3.2
5.5
.16
STRIPPER
SUPERNATE
TOTAL P ORTHO P
mg/1 mg/1
10.0
12.0
11.0
9.0
11.0
9.2
10.1
10.8
10.0
10.3
10.5
11.2
14.6
16.2
21.0
25.0
25.0
17.5
13.5
13.5
13.6
25.0
9.2
10.0
10.5
12.0
10.0
12.0
12.0
13.0
12.0
13.0
26.0
8.0
13.0
19.0
19.0
30.0
28.0
25.0
18.0
15.0
15.0
16.0
30.0
8.0
AERATION
TOTAL P
FILTERED
rng/1
0.5
0.5
2.0
0.5
2.0
2.4
3.4
2.8
2.4
2.6
3.0
3.6
4.1
5.7
3.5
3.0
2.2
1.5
3.0
2.8
2.6
5.7
0.5
*
EFFLUENT STRIPPER
TOTAL P INFLUENT
TOTAL P
mg/1 mg/1
43
41
47
44
46
48
37
50
59
57
60
59
57
61
52
58
55
57
40
41
51
61
37
210
190
245
235
230
240
205
270
300
.290
270
280
265
260
250
260
265
200
190
185
242
300
185
WASTE
SLUDGE
TOTAL P
mg/1
210
190
245
235
230
240
205
270
300
290
270
280
265
260
250
260
265
200
190
185
242
300
185
CLARIFIER
STRIPPER UNDERFLOW UNDERFLOW
FILTERED FILTERED
TOTAL P TOTAL P TOTAL P
mg/1 mg/1 mg/1
470
430
435
540
480
470
385
335
340
400
370
390
365
380
410
385
400
395
415
460
413
540
335
95
94
85
89
79
85
76
47
49
51
51
62
63
73
79
86
92
102
95
94
77
102
47
19
5.5
9.5
4
8.5
10.5
9.5
13
17
16
12
13
18.5
-
17.5
-
-
10
15
6.5
12
18.5
4
•SECONDARY CLARIFIER UNDERFLOW
-------
TABLE A-4. PHASE II OPERATING CONDITIONS
FOR PHOSTRIP PILOT PLANT - RENO/SPARKS, NEVADA
DATE
2-23-76
2-24-76
2-25-76
2-26-76
2-27-76
2-28-76
2-29-76
3-01-76
3-02-87
3-03-76
3-04-76
3-05-76
3-06-76
3-07-76
AVERAGE
PLANT
INF ELUTRIATION
6PM 6PM ZQ
4.7
4.7
4.7
4.7
4.7
-
-
4.7
4.7
4.7
-
4.7
-
-
4.7
0.74
0.76
0.76
0.75
0.75
-
-
• 0.75
0.72
0.72
0.76
0.75
-
i
0.75
0.75
16
16
16
16
16
-
-
16
15
15
-
16
-
16
16
*
STRIPPER
INFLUENT
GPM ZQ
0.71
0.71
0,69
0.71
0.71
-
0.72
0.69
0.70
0.71
0.71
0.71
-
0.70
0.71
15
15
15
15
15
-
15
15
15
15
15
15
-
15
15
STRIPPER
UNDERFLOW
GPM ZQ
0.57
0.56
0.56
0.57
0.57
-
-
0.6
0.55
0.55
0.55
0.55
-
-
0.56
12
12
12
12
12
-
-
13
12
12
12
12
-
-
12
AER
RTq
HRS
6.0
6.0
6.0
6.0
6.0
-
-
6.0
6.0
6.0
-
6.0
-
-
6.0
AVG
D.O.
ng/1
1.1
1.2
1.2
1.1
1.3
2.0
1.8
2.5
2.3
3.3
1.6
3.4
2.6
1.9
2.0
STRIPPER
BLANKET M.L.
HEIGHT STRIPPER TEMP
INCHES SRT HRS "F
69
68
63
64
67.5
67
66
56
59
59
58.5
58
63
68
63.3
13.3
13.4
12.4
12.4
13.0
-
-
10.3
11.8
11.8
11.7
11.6
-
-
12.5
59
60
59
60
60
61
60
59
58
59
58
58
58
58
59
STRIPPER
INFLUENT
gfef!
944
836
928
828
1004
866
812
802
964
732
948
680
2336
814
964
^f
916
708
836
752
876
758
662
684
856
672
776
656
2286
692
867
§S?1
6860
5090
-
5970
5290
5730
5080
5610
5243
5663
4710
5936
4130
4770
5391
S$!
-
4270
-
5160
4530
4710
4340
4900
4630
4876
4150T
4710
3570
4140
4499
STRIPPER
UNDERFLOW
§i?i BH
8090
7570
8290
8540
7740
7360
6780
7550
8540
9080
7280
7200
7040
7090
7725
-
6440
7060
7440
6760
6150
5800
6290
7320
7890
5950
5840
6080
6110
6549
WASTE
SLUDGE
GAL/DAT
84
99
96
96
106
118
122
96
102
108
104
100
108
114
103.8
CHEMICAL
CLARIFIER
INFLUENT
pH
-
-
-
-
-
-
8.2
8.8
9.0
8.8
8.8
9.0
9.0
9.1
8.8
* SECONDARY CLARIFIER UNDERFLOW
-------
TABLE A-5. PHASE II ORGANIC & SUSPENDED SOLIDS
REMOVALS FOR PHOSTRIP PILOT PLANT - RENO/SPARKS, NEVADA
DATE
2-23-76
2-24-76
2-25-76
2-26-76
2-27-76
2-28-76
2-29-76
3-01-76
3-02-76
3-03-76
3-04-76
3-05-76
3-06-76
3-07-76
COD,
INF
237
238
226
238
226
206
241
204
216
241
238
234
277
243
mg/1
EFF
13
64
27
27
27
20
25
20
20
20
42
17
24
24
TSS,
INF
115
99
97
101
111
112
123
-
43
77
101
59
72
92
mg/1
EFF
27
-
19
15
33
32
33
3
-
1
13
4
9
15
VSS,
INF
-
92
95
97
105
106
92
-
32
77
76
51
60
79
mg/1
EFF
21
-
14
11
27
30
32
2
-
1
9
3
8
11
AVERAGE 233 26 93 17 80 14
-------
TABLE A-6. PHASE II PHOSPHORUS BALANCE DATA
FOR PHOSTRIP PILOT PLANT - RENO/SPARKS, NEVADA
INFLUENT
DATE
2-23-76
2-24-76
2-25-76
2-26-76
2-27-76
2-28-76
2-29-76
3-01-76
3-02-76
3-03-76
3-04-76
3-05-76
3-06-76
3-07-76
AVERAGE
MAXIMUM
MINIMUM
TOTAL P
mg/1
8.5
9.2
8.7
8.2
8.5
8.0
9.7
8.0
7.3
8.6
7.1
8.0
8.2
9.4
8.4
9.4
7.1
ORTHO P
mi/1
7.0
7.8
7.8
7.0
7.2
7.0
8.4
6.2
5.4
5.0
4.8
5.6
6.2
6.2
6.5'
8.4
4.8
EFFLUENT
TOTAL P
mg/1
1.4
1.17
.98
.54
.47
.46
.72
.51
.48
.55
.56
.73
.82
.74
.72
1.4
.46
ORTHO P
mg/1
.78
1.12
.79
.33
.26
.28
.51
.33
.21
.28
.30
.43
.66
.51
.49
1.12
.21
STRIPPER
SUPERNATE
TOTAL P
mg/1
36
40
37
35
35
34
34
33
29
32
28
27
34
33
33
40
27
ORTHO P
-8/1
36
37
35
31
35
34
34
31
27
28
27
25
33
30.5
32
37
25
*
AERATION EFFLUENT STRIPPER
TOTAL P TOTAL P INFLUENT
FILTERED TOTAL P
mg/1 mg/1 mg/1
1.4
1.9
.5
.5
.6
.6
.8
.5
.7
.6
.7
.8
.5
.5
.76
1.9
0.5
32
33
30
32
25
28
30
34
33
31
20
25
29
28
29
34
20
195
210
-
200
200
170
195
200
180
185
175
215
175
170
190
215
170
HASTE
SLUDGE
TOTAL P
mg/1
195
210
-
200
200
170
195
200
180
185
175
215
175
170
190
215
170
STRIPPER
UNDERFLOW
TOTAL P
mg/1
230
225
265
225
240
210
185
220
225
220
185
185
190
225
216
265
185
FILTERED
TOTAL P
mg/1
25
27
33
33
32
28
36
29
27
32
27
34
29
33
30
36
25
CLARIFIER CHEMICAL
UNDERFLOW CLARIFIER
FILTERED SUPERNATANT
TOTAL P
mg/1
3.0
2.2
4.0
1.5
2.3
.8
1.4
.9
1.1
.9
1.4
1.1
1.0
1.1
1.6
4.0
.8
TOTAL P
«g/l
-
-
-
-
-
-
-
-
2.9
8.5
3.5
8.0
7.5
9.9
6.7
9.9
2.9
ORTHO P
mg/1
1.2
-
-
2.6
-
-
-
5.6
2.4
5.6
5.2
3.2
2.6
3.4
3.5
5.6
1.2
"SECONDARY CLARIFIER UNDERFLOW
-------
TABLE A-7. PHASE III OPERATING CONDITIONS
FOR PHOSTRIP PILOT PLANT - BEND/SPARKS, NEVADA
NJ
DATE
3-20-76
3-21-76
3-22-76
3-23-76
3-24-76
3-25-76
3-26-76
3-27-76
3-28-76
3-29-76
3-30-76
3-31-76
4-01-76
4-02-76
PLANT
INF
GPM
-
-
5.14
5.14
5.14
5.14
5.14
-
5.14
5.15
5.14
5.15
5.14
5.15
ELUTRIATION
GPM ZQ
0.47
0.47
0.47
0.47
-
0.47
0.47
-
0.47
0.47
0.47
0.47,
0.47
0.47
-
-
10
10
-
10
10
-
10
10
10
10
10
10
*
STRIPPER
INFLUENT
GPM ZQ
0.65
0.65
0.65
0.65
0.65
0.65
0.65
-
0.65
0.65
0.65
0.65
0.65
0.65
-
-
14
14
14
14
14
-
14
14
14
14
14
14
STRIPPER
UNDERFLOW
GPM ZQ
0.55
0.55
0.55
0.55
0.55
0.55
0.55
-
0.55
0.54
0.55
0.54
0.55
0.54
-
-
12
12
12
12
12
-
12
12
12
12
12
12
AER AVG
RTQ D.O.
HRS mg/1
-
-
5.45
5.45
5.45
5.45
5.45
-
5.45
5.46
5.45
5.46
5.45
5.46
1.9
1.7
1.5
1.2
1.3
1.5
1.8
1.5
1.8
2.3
1.3
1.7
1.3
1.1
STRIPPER
BLANKET M.L.
HEIGHT STRIPPER TEMP
INCHES SRT HRS *F MLSS
53
54
56
58
55
56
55
56
61
63
55
58
57
63
10.6
10.8
11.2
11.6
11.0
11.2
11.0
-
12.2
12.9
11.0
11.8
11.4
12.9
62
62
62
62
63
62
62
62
62
62
62
63
62
62
1352
1216
1212
1124
1204
1052
1124
955
1096
1180
1000
870
590
960
*
STRIPPER
INFLUENT
MLVSS
pg/T
1136
1044
1044
1028
1008
928
1032
870
1012
1076
985
790
510
810
RSS
•(71
8890
8710
9500
8540
8484
8030
7850
7910
5670
7550
8200
8230
8200
7180
5??
7520
7390
7990
7270
7144
6880
6720
6840
6770
6530
6980
6900
6990
6240
STRIPPER WASTE
UNDERFLOW SLUDGE
RSS RVSS GAL/DAY
11090
10250
10860
10490
12006
10020
10400
10660
11220
10170
10260
10260
10360
9560
9370
7850
9190
8840
10145
8790
9000
9240
9740
8860
8750
8840
8850
8170
56
34
30
54
52
48
42
36
44
58
42
38
48
54
CHEMICAL
CLARIFIER
INFLUENT
PH
8.7
8.7
11.2
7.7
8.7
9.2
9.8
9.2
9.2
10.4
9.5
9.6
9.3
10.4
AVERAGE 5.14 0.47 10 0.65 14 0.55 12 5.45 1.6 57.1 11.4
* SECONDARY CLARIFIER UNDERFLOW
62 1067 948 8067 7012 10543 8974 45.4 9.4
-------
to
TABLE A-8. PHASE III ORGANIC & SUSPENDED SOLIDS
REMOVALS FOR PHOSTRIP PILOT PLANT - RENO/SPARKS, NEVADA
DATE
3-20-76
3-21-76
3-22-76
3-23-76
3-24-76
3-25-76
3-26-76
3-27-76
3-28-76
3-29-76
3-30-76
3-31-76
4-01-76
4-02-76
COD,
INF
301
256
223
223
239
261
261
253
212
233
207
219
235
247
tog A
EFF
27
32
40
-
27
33
37
41
33
33
24
32
12
10
TSS,
INF
102
97
107
120
117
89
107
77
89
100
64
95
116
87
mg/1
EFF
20
20
27
42
33
39
40
13
22
15
11
2
39
54
VSS,
INF
98
94
105
115
112
87
106
67
-
-
64
95
85 '
84
mg/1
EFF
13
17
21
27
32
25
26
10
15
15
9
1
33
49
AVERAGE 241 29 98 27 93 21
-------
TABU A-9. PHASE III PHOSPHORUS BALANCE DATA
FOR PHOSTRIP PILOT PLANT - RENO/SPARKS, NEVADA
INFLUENT
DATE
3-20-76
3-21-76
3-22-76
3-23-76
3-24-76
3-25-76
3-26-76
3-27-76
3-28-76
3-29-76
3-30-76
3-31-76
4-01-76
4-02-76
AVERAGE
MAXIMUM
MINIMUM
TOTAL P
-g/1
8.3
9.6
9.4
10.1
10.0
9.5
10.7
10.5
10.3
10.5
9.2
7.8
7.7
7.6
9.4
10.7
7.6
ORTHO P
6.8
7.8
8.3
8.8
8.5
8.4
9.0
8.5
8.7
8.5
7.7
6.8
6.4
6.4
7.9
9.0 '
6.4
EFFLUENT
TOTAL P
mg/1
.79
.72
.77
1.8
1.5
.5
1.2
1.1
.5
.5
.4
.4
.5
.5
.8
1.8
.4
ORTHO P
mg/1
.69
.62
.69
-
1.44
.31
1.04
0.6
.26
.25
.24
.1
.18
.14
.61
1.44
.1
STRIPPER
SUPERNATE
TOTAL P
mg/1
52
53
57
64
64
55
53
60
57
57
56
52
55
51
56
64
51
ORTHO P
mg/1
50
51.5
56
62.5
64
61
58
65
61
61
60
56.5
53
51
58
65
50
*
AERATION EFFLUENT STRIPPER
TOTAL P TOTAL P INFLUENT
FILTERED TOTAL P
og/1 ag/1 mg/1
0.7
0.8
1.2
3.5
0.8
0.2
1.3
0.6
0.4
0.5
0.4
0.4
0.5
0.4
.84
3.5
0.4
48
51
44
-
-
48
48
43
-
-
52
48
48
45
48
52
43
320
350
410
395
385
335
330
300
355
350
370
350
185
300
338
410
185
WASTE
SLUDGE
TOTAL P
mg/1
320
350
410
395
385
335
330
300
355
350
370
350
185
300
338
410
185
STRIPPER
UNDERFLOW
TOTAL P
mg/1
365
385
400
410
415
375
375
355
385
340
540
380
345
340
386
540
340
FILTERED
TOTAL P
mg/1
47
46
44
-
-
47
51
52
-
-
48
41
38
38
45
52
38
CLARIFIER CHEMICAL
UNDERFLOW CLARIFIER
FILTERED SUPERNATANT
TOTAL P
mg/1
3.8
5.3
8.8
-
-
6.9
4.7
4.4
-
-
5.8
7.1
2.0
0.9
5.0
8.8
.9
TOTAL P
mg/1
19.8
13.4
29.2
-
-
—
12
-
-
5.8
7.1
2.0
0.9
11.3
29.2
.9
ORTHO P
Bg/1
-
13.5
24.5
3$
6.3
2.4
.4
4.2
3.8
.3
1.0
.4
1.6
.8
2.4**
39
.3
* Secondary Clarifier Underflow
**MEDIAN
-------
TABLE A-10. FULL SCALE PERFORMANCE DATA
PHOSTRIP SLUDGE RECYCLE SYSTEM
RENO/SPARKS, NEVADA
pH & TEMPERATURE °C*
FEED
DATE
9-13-75
9-14-75
9-15-75
9-16-75
9-17-75
9-18-75
9-19-75
9-20-75
9-21-75
9-22-75
9-23-75
9-24-75
9-25-75
9-26-75
9-27-75
MEDIAN
MIN
7.1
7.1
7.0
7.2
7.1
7.1
7.1
7.0
6.9
6.9
7.1
6.9
6.9
6.9
7.0
7.0
MAX
7.4
7.2
7.3
7.5
7.4
7.4
7.3
7.3
6.9
7.3
7.2
7.7
7.8
-
7.2
7.3
EFF
MIN
7.2
7.3
7.2
7.3
7.5
7.1
7.2
7.1
7.0
7.1
7.2
7.2
7.2
6.9
7.1
7.2
MAX
7.7
7.6
7.6
7.7
7.7
7.6
7.4
7.4
7.3
7.5
7.5
7.6
-
-
7.4
7.6
AEROBIC
RECYCLE
MIN
6.7
6.7
6.7
6.6
6.8
6.8
6.8
6.8
6.7
6.8
6.8
6.9
6.8
6.8
6.8
6.8
MAX
6.8
6.6
6.6
6.8
6.7
6.9
6.9
6.7
6.7
6.8
6.7
6.9
6.8
6.8
6.8
6.8
ANOXIC
RECYCLE
MIN
6.4
6.4
6.3
6.4
6.4
6.4
6.4
6.4
6.4
6.4
6.4
6.4
6.5
6.5
6.4
6.4
MAX
6.4
6.3
6.3
6.4
6.3
6.5
6.5
6.2
6.3
6.4
6.4
6.4
6.4
6.4
6.4
6.4
STRIPPER
SUPERNATANT
MIN
6.5
6.5
6.4
6.6
6.5
6.6
6.5
6.5
6.5
6.6
6.7
6.6
6.7
6.6
6.6
6.6
MAX
6.5
6.4
6.4
6.5
6.4
6.6
6.5
6.4
6.5
6.5
6.5
6.6
6.5
6.6
6.5
6.5
AERATION BAY
END
MIN MAX
7.0
6.7
-
7.0
-
7.0
-
6.7
-
6.9
-
7.2
-
6.8
-
7.0
TEMP
24
23
23.5
23
23
23.5
23.5
23.5
23
23
23
23
23
23
23
23
AERATION
RATE
FT3/GAL
1.5
1.5
1.6
1.6
1.6
1.6
1.6
1.6
1.5
1.5
1.5
1.3
1.2
1.3
1.6
1.5
*GRAB SAMPLES
-------
to
en
TABLE A-ll. FULL SCALE PERFORMANCE DATA
PHOSTRIP SLUDGE RECYCLE SYSTEM
RENO/SPARKS, NEVADA
FLOW RATES (MGD)
DATE
9-13-75
9-14-75
9-15-75
9-16-75
9-17-75
9-18-75
9-19-75
9-20-75
9-21-75
9-22-75
9-23-75
9-24-75
9-25-75
9-26-75
9-27-75
FEED
MIN MAX
4.9
4.6
4.4
3.8
3.8
3.6
4.0
4.2
4.0
3.7
3.7
4.0
3.9
4.0
3.9
7.0
5.9
6.9
6.7
6.8
6.9
6.8
6.5
6.2
6.8
6.8
6.8
5.8
6.6
-
AEROBIC
RECYCLE
MIN MAX
1.37
1.17
1.17
1.17
1.17
1.17
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.78
1.65
1.65
1.94
1.80
1.91
1.98
1.98
1.98
1.98
1.98
1.98
1.98
1.98
1.98
ANOXIC
RECYCLE
MIN MAX
.62
.62
.62
.62
.62
.62
.62
.62
.62
.62
.62
.62
.62
.62
.62
1.1
1.1
1.1
1.1
1.1
1.1
1.1
1.1
1.1
1.1
1.1
1.1
1.1
1.1
1.1
STRIPPER
SUPERNATANT
MIN MAX
.75
.55
.55
.55
.55
.55
.88
.88
.88
.88
.88
.88
.88
.88
.88
.68
.55
.55
.84
.70
.81
.88
.88
.88
.88
.88
.88
.88
.88
.88
SLUDGE
WASTE RECYCLE
(CLARIFIER) MIN MAX
.08
.178
.116
.134
.128
.153
.259
.311
.318
.131
.073
.132
.215
.106
.107
1.12
1.12
1.12
1.12
1.12
1.12
1.12
1.12
1.12
1.12
1.12
1.12
1.12
1.12
1.12
.64
.64
.64
.64
.64
.64
.64
.64
.64
.64
.64
.64
.64
.64
.64
BLANKET
CLAR
MIN/MAX
.1/.3
.05/. 05
.08/.08
.05/. 08
.08/.08
.05/. 08
.05/.05
.08/.05
.08/.1
.08/.1
.l/.l
.08/.08
.17.1
.087.05
.08/.05
DEPTH (m)
STRIPPER
MIN/MAX
1.3/.9
1.2/1.4
1.2/1.3
1.1/.9
1.1/.9
1.3/.9
.91.1
1.0/1.0
1.2/1.4
1.4/1.3
1.4/1.3
1.1/1.1
1.1/1.3
1.6/1.5
1.2/1.3
MEAN
3.9 6.6 1.38 1.94 .62 1.1
.76
.84
.17
1.12 .64 .08/.09 1.2/1.2
-------
TABLE A-12. FULL SCALE PERFORMANCE DATA
PHOSTRIP SLUDGE RECYCLE SYSTEM
RENO/SPARKS, NEVADA
ORTHO PHOSPHORUS (mg/1)
FEED
DATE
9-13-75
9-14-75
9-15-75
9-16-75
9-17-75
9-18-75
9-19-75
9-20-75
9-21-75
9-22-75
9-23-75
9-24-75
9-25-75
9-26-75
9-27-75
MEAN
MINIMUM
MAXIMUM
MIN
5.0
6.2
6.8
6.0
5.1
6.4
6.2
5.8
5.8
6.2
5.7
19.0
16.5
6.0
5.3
7.5
5.0
19.0
MAX
6.5
7.6
7.4
5.5
6.2
7.2
6.8
7.2
7.6
6.8
6.3
5.7
6.0
5.7
7.0
6.6
5.5
7.6
EFFLUENT
MIN
.15
-
.55
.25
.15
.28
.08
.08
.05
.15
.18
.98
.98
.48
.38
.33
.05
.98
MAX
.85
.35
.6
.23
.15
.25
.10
.25
.13
.33
.55
.20
-
1.0
.3
.38
.1
1.0
AEROBIC
RECYCLE
MIN
11
14
13
18
14
5.5
2.0
3.8
2
5.3
3.5
6.5
6.5
4.5
4
7.6
2
18
MAX
10
12.5
12.5
14.5
7.5
13.5
7.5
4.0
.05
6.5
7.0
9.0
11.5
-
2
8.4
.05
14.5
ANOXIC
RECYCLE
MIN
64
64
69.5
83
74
76
72
60
56
60
57
68
68
52
66
66
52
83
MAX
52
55
60
74
72
68
55
60
56
43
50
63
62
46
58
58
43
72
STRIPPER
SUPERNATANT
MIN
48
43
42
55
48
46
47
40
36
32
36
45
39
33
43
42
32
55
MAX
44
45
43
51
50
49
45
42
36
31
33
44
39
28
40
41
28
51
AERATION
GRAB
MIN MAX
.02
.05
-
.11
-
.02
-
.03
-
.01
-
.04
-
.02
-
.04
.01
.11
-------
00
TABLE A-13. FULL SCALE PERFORMANCE DATA
PHOSTRIP SLUDGE RECYCLE SYSTEM
RENO/SPARKS, NEVADA
SUSPENDED SOLIDS (ng/1)
DATE
9-13-75
9-14-75
9-15-75
9-16-75
9-17-75
9-18-75
9-19-75
9-20-75
9-21-75
9-22-75
9-23-75
9-24-75
9-25-75
9-26-75
9-27-75
MEAN
MINIMUM
MAXIMUM
MEAN C
INFLUENT
TSS VSS/TSS
C
132
96 - *
113
198
113
105
122
76
79
118
106
113
93
133
104
i
-
76
198
113
EFFLUENT MIXED LIQUOR
TSS
MIN/MAX
20C
11C
19C
14C
15C
IOC
12C
9C
8C
27/15
10/18
23/12
31/-
15C
6/7
19/13
6/7
31/18
13
VSS/TSS TSS
MIN MAX
1140C
1304C
1122C
1154C
1296C
1150C
1078C
938C
974C
.86 1068C
.6 1168
.66 992C
.87 1178C
1306C
1356C
.75 1168
1168
1168
1147
.
1200
629
673
716
1320
460
507
-
-
680
612
-
-
755
460
1320
-
VSS/TSS
.79
.78
.75
.73
.76
.82
-
.83
-
-
.82
.78
-
-
.78
.73
.83
.78
ANOXIC RECYCLE
TSS
MIN
—
10896
10376
12396
-
11972
10272
9672
8972
6400
8632
7688
8804
10528
8508
9624
6400
12396
-
MAX
_
10144
10172
9692
10700
10140
8404
8752
7292
7992
7980
8564
8748
8236
10924
9124
7292
10924
-
VSS/TSS
_
.77
.77
.78
.79
.79
.80
.81
.81
.84
.82
.78
.82
.83
.83
.80
.77
.84
-
AEROBIC RECYCLE
TSS
MIN
5237
7572C
3088
8608
1848
1792
1756
2560
2344
2532
2860
2684
2316
2168
3061
1756
8608
7572
MAX
8158C
4916
4860
6360
6292
5864
5032
3952
2784
3444
5316
4016
4428
4332
3064
4618
2784
6360
8158
VSS/TSS
.79
.78
.81
.79
.80
.79
.78
.83
.84
.81
.83
.81
.83
.83
.77
.81
.77
.84
.79
STRIPPER
SUPERNATANT
TSS
MIN MAX
_
8
20
60
88
84
64
110
110
58
35
•68
54
85
-
65
8
110
-
164
116
-
92
112
132
96
99
67
36
73
72
60
52
87
90
36
164
-
VSS/TSS
.51
.50
.69
.84
.72
.89
.76
-
.9
.84
.83
.82
.83
.87
-
.77
.50
.90
-
C - 24 HR COMPOSITE
-------
CD
TABLE A-14. FULL SCALE PERFORMANCE DATA
PHOSTRIP SLUDGE RECYCLE SYSTEM
RENO/SPARKS, NEVADA
BOD , COD, DISSOLVED OXYGEN (mg/1)
BOD COD
DATE INF EFF
9-13-75
9-14-75
9-15-75
9-16-75
9-17-75 103 16
9-18-75
9-19-75 -
9-20-75
9-21-75 -
9-22-75
9-23-75
9-24-75 -
9-25-75
9-26-75
9-27-75
INF
MIN MAX
196
272
188
188
145
205
206
156
156
-
-
181
151
194
-
243
264
285
247
272
255
243
256
306
-
-
276
260
288
_
EFF
MIN MAX
48
40
37
44
36
44
35
39
39
48
-
36
39
36
-
44
48
36
44
36
44
31
35
35
34
-
32
34
33
-
DISSOLVED OXYGEN
AEROBIC ANOXIC STRIPPER END OF
EFF RECYCLE RECYCLE SUPERNATANT AERATION
MIN MAX MIN MAX MIN MAX MIN MAX MIN MAX
___ __ __ _ _ __
2.6 .2 - .3 .5 - .7
________ __
2.9 - .6 - .2 - .6 - 1.5
________ __
2.9 - .4 - .3 - .8 - 1.8
_-_--___ __
3.3 - .5 - .4 - .7 - 1.1
_--__--_ __
3.7 - .4 - .3 - 0.8 - 1.8
-----___ __
4.9 - 1.6 - 0.2 - 1.5 - 2.2
-------- __
__----__ __
-_ -_ _- - _ __
MEAN
103 16
187 266 40 37
3.7 3.3 .4 .7
.3
.3
.8
.8
1.5
-------
TABLE A-15. FULL SCALE PERFORMANCE DATA
PHOSTRIP SLUDGE RECYCLE SYSTEM
RENO/SPARKS, NEVADA
TOTAL PHOSPHORUS (mg/1)
DATE
9-13-75
9-14-75
9-15-75
9-16-75
9-17-75
E 9-18-75
9-19-75
9-20-75
9-21-75
9-22-75
9-23-75
9-24-75
9-25-75
9-26-75
9-27-75
MEAN
MINIMUM
MAXIMUM
FEED
MIN MAX
7.4
9.0
8.4
7.8
6.4
8.2
8.2
8.3
7.4
8.4
7.1
21
18.4
9.5
8.1
9.6
6.4
21
8.8
9.6
9.5
7.8
8.5
8.9
9.1
9.3
10.2
9.9
9.3
8.5
8.9
8.5
9.6
9.1
7.8
10.2
EFFLUENT AERATION
MIN MAX MIN MAX
1.0
-
1.3
1.2
1.0
1.2
0.5
0.5
0.6
0.7
0.9
1.6
1.4
0.9
0.8
1.0
.5
1.6
-
1.5
1.4
1.2
0.8
1.2
0.5
0.6
0.5
0.7 27
0.8
0.9 -
-
1.0
0.4
0.8 27
0.4 27
1.5 27
-
33
29
34
-
30
26
28
-
27
-
27
-
36
-
30
26
36
AEROBIC RECYCLE
MIN
123
103
114
-
122
62
80
104
98
110
126
118
110
76
108
104
62
126
MAX
-
138
198
178
206
184
176
150
114
154
190
156
150
140
116
161
116
206
MIN
FILT
-
-
-
-
-
—
8
5.5
-
6
7.5
8
6
4
6.4
4
8
MAX
FILT
-
-
-
-
-
—
6
4
-
8
9
13.5
7.5
4.5
7.5
4
13.5
ANOXIC
MIN
213
-
250
260
276
294
266
252
250
264
300
262
238
244
228
257
213
300
MAX
-
206
244
256
286
266
240
220
222
266
248
244
208
206
248
240
206
286
RECYCLE
MIN MAX
FILT FILT
-
70.5
73.5
78
77
79
75
62.5
54.5
63
56
68
66
53
-
67
53
79
-
60
62
71
67
71
58.5
-
49.5
50
51
62
62
48
61
55
48
71
STRIPPER
SUPERNATANT
MIN MAX
48.5
48.5
45
49.5
46
49.5
50
45.5
38
36
37
44
44
35
-
44
35
50
-
45
46.5
48
46.5
49.5
53
41.5
36.5
34
37
42
43.5
32
24
41
24
53
-------
TABLE A-16. FULL SCALE PERFORMANCE DATA
PHOSTRIP SLUDGE RECYCLE SYSTEM
RENO/SPARKS, NEVADA
(CONTROL)
DATE
9-13-75
9-14-75
9-15-75
9-16-75
9-17-75
9-18-75
9-19-75
9-20-75
9-21-75
9-22-75
9-23-75
9-24-75
9-25-75
9-26-75
9-27-75
MEAN
FEED
FLOW
(MGD)
MIN MAX
4.9
4.6
4.4
3.8
3.8
3.6
4.0
4.2
4.0
3.7
3.7
4.0
3.9
4.0
3.9
3.9
7.0
5.9
6.9
6.7
6.8
6.9
6.8
6.5
6.2
6.8
6.8
6.8
5.8
6.6
-
6.6
RECYCLE
(MGD)
AVE
1.91
1.97
2.01
1.98
1.96
1.80
1.66
1.50
1.53
1.80
2.47
1.97
1.82
1.76
1.63
1.85
MLSS
mg/1
AVE
1,046
974
1,048
1,078
1,200
1,014
1,050
940
996
924
894
868
886
1,050
1,014
1,000
RSS
mg/1
AVE
4,742
4,986
4,274
3,686
4,270
3,290
4,248
5,242
4,362
4,650
3,204
3,366
3,728
3,440
3,410
4,060
AERATION
RATE
FT3/GAL
1.1
1.1
1.4
1.5
1.4
1.5
1.4
1.4
1.4
1.4
1.4
1.4
1.3
1.2
1.5
1.4
ESS
mg/1
10
9
20
8
15
18
14
7
9
19
12
14
15
22
18
14
WAS
MGD
.204
.204
.219
.205
.204
.194
.186
.162
.168
.195
.253
.210
.198
.197
.175
.198
-------
DATE
11-22-76
11-23-76
11-24-76
11-25-76
11-26-76
11-27-76
11-28-76
11-29-76
Uifl_7£
~Jlr~/O
12-01-76
12-02-76
12-03-76
12-04-76
12-05-76
12-06-76
12-07-76
12-08-76
12-09-76
12-10-76
12-11-76
12-12-76
12-13-76
12-14-76
12-15-76
12-16-76
12-17-76
12-18-76
12-19-76
12-20-76
12-21-76
12-22-76
12-23-76
12-24-76
12-25-76
12-26-76
12-27-76
12-28-76
12-29-76
12-30-76
12-31-76
01-01-77
01-02-77
01-03-77
01-04-77
01-05-77
01-06-77
01-07-77
01-08-77
01-09-77
01-10-77
01-11-77
01-12-77
01-13-77
01-14-77
01-15-77
01-16-77
01-17-77
01-18-77
01-19-77
01-20-77
01-21-77
01-22-77
01-23-77
01-24-77
01-25-77
01-26-77
01-27-77
01-28-77
01-29-77
01-30-77
TABLE A-17
PUOSTRIP U
AEBOBIC RECYCLE
FEED 1 2
FEED HIGH/LOW HIGH UN HIGH LOU
11.44 - -
11.89 - -
12.00
10.98
12.00
11.80
11.69 ...
11.87
11.78 -
11.82 - - -
11.61
11.80 1.56 1.56 1.31 1.31
11.47 1.26 1.26 1.16 1.16
11.49
11.57 1.40 1.40 1.21 1.21
11.52 1.35 1.35 1.15 1.15
11.54
11.14
11.53
11.48
11.15 1.33 1.33 1.07 1.07
11.15 1.34 1.34 1.05 l.OS
11.15 1.35 1.35 0.95 0.95
11.40 - -
11.20
11.80
11.60 -
11.80
11.80
12 . 20
10.60
11.40 t -
12.20
12.40 - -
12.40 0.59 - 0.91
12.40 0.58 0.59
12.60
13.20
14.00
12.00 0.47 0.59
12.80 - 0.50 0.60
12.00 - 0.82 0.86
12.20 15.3/6.7 0.89 0.88 0.92 1.24
11.20 14/9 0.86 0.63 0.91 0.53
12.00
11.40
12.80 15.3/7.3 0.89 0.52 0.91 0.53
12.80 15.3/7.3 0.89 0.49 0.91 1.51
11.60 14/7.3 0.86 - 0.92
11.60 14/7.3 0.88 0.48 0.92 0.53
12.80 14/7.3 0.89 0.50 0.95 0.60
12.80
11.20
12.20 15.3/9 0.86 0.52 0.89 0.56
11.60 15.3/9 0.84 - 0.94
11.40 15.3/9 0.53 - 0.53
12.00
12.60 15.3/9 0.55 0.53
12.00 - -
11.20
11.60 15.3/9 0.80 0.91
11.60 16.7/10 0.82 0.51 0.87 0.53
12.20 16/10 0.86 0.88 -
12.00 16/9.3 0.52 0.59
11.10 16.7/10 - 0.51 - 0.62
11.44
11.09
. FULL SCALE
PE STSTEH - RE
FLOW RATES,
AROXIC RE
1
BICE LOU H
0.52 - 0
0.65 - 0
0.63 0
0.60 - 0
0.52 - 0
0.35 0
_
0.76 0.76 0
0.77 0.77 0
-
0.79 0.79 0
0.78 0.78 0
- -
-
-
0.78 0.78 0
0.73 0.73 0
0.65 0.65 0
- -
-
- -
- -
- -
-
-
- -
0.62 0
0.07 -
-
-
-
0.07
0.12
0.54 - 0
0.59 0.48 0
0.57 0.32 0
-
-
0.51 0.29 0
0.66 0.32 0
0.71 0
0.63 0.27 0
0.60 0.33 0
-
- -
0.63 0.33 0
0.59 0
0.36
-
0.35 -
-
-
0.55 - 0
0.60 0.28 0
0.62 - 0
0.32 -
0.32 -
-
- -
FERF
HO/8
HGD
area.
2
IGH
.58
.60
.(0
.60
.63
.56
.59
.70
.84
.84
.83
.77
.76
.62
.63
.63
.65
.60
.69
.66
.69
.60
.59
.60
.58
.64
.59
WDttNC]
PARKS.
I
LOU
-
-
-
0.59
0.70
0.84
0.84
-
-
-
0.83
0.77
0.76
-
-
-
-
-
_
-
-
-
-
-
0.33
-
-
-
0.27
0.28
-
0.36
0.33
-
0.35
0.35
-
0.39
0.39
-
0.40
1.31
0.43
0.39
-
-
0.38
-
0.37
0.38
-
-
I DATA
DEVAIM
STRIP
SUPEM
HICO
1.68
1.69
1.61
1.53
1.65
1.45
1.69
-
1.96
2.24
1.56
1.96
-
-
1.49
1.61
1.87
-
-
-
-
-
-
1.73
2.09
-
-
-
.
2.12
1.37
1.73
2.45
1.51
1.44
1.87
-
1.66
1.80
-
-
-
2.09
1.80
1.73
-
-
L
TEB
ATAHT
LOH
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
2.08
2.16
1.58
1.51
1.51
-
1.51
2.02
1.37
1.51
-
1.51
-
1.58
-
1.66
-
-
-
1.92
-
1.80
1.77
-
.
STRIPPER
ELUTR1ANT.
1.10
1.15
1.03
0.98
0.76
1.18
0.50
1.29
0.64
1.14
-
1.40
1.28
1.15
.
-
-
-
1.66
1.66
H1GB/LOH
-/I. 36
-11. 20
.58/-
.65/.6S
.50/.43
.437.36
1.51/.58
.797-
.79/1.01
1.15/1.01
1.08/1.22
1.58/-
-/1.30
-
-11.11
-
1.58/-
1.34/1.44
!.*»/-
-/1.51
-/I. 37
.
-
TOT
RET
1
-
1.58
1.45
1.51
1.66
1.69
1.53
1.37
1.45
1.48
1.49
1.50
1.45
1.50
1.48
1.43
1.43
1.40
1.42
1.48
1.35
1.31
1.33
1.45
1.60
1.41
1.42
1.41
1.45
1.44
1.54
1.49
1.45
1.41
1.43
1.25
1.43
1.34
1.17
1.05
1.04
1.17
1.33
1.21
1.16
1.25
1.21
1.26
1.30
1.25
1.22
1.30
0.99
1.83
1.02
1.12
1.06
1.04
0.99
1.10
1.27
1.24
AL
ms
2
-
1.70
1.46
1.75
1.67
1.82
1.60
1.53
1.36
1.36
1.33
1.28
1.34
1.33
1.32
1.39
1.29
1.42
1.44
1.47
1.45
1.45
1.41
1.57
1.53
1.44
1.43
1.43
1.61
1.63
1.69
1.55
1.79
1.81
1.88
1.60
1.94
1.87
1.74
1.87
1.55
1.68
1.89
1.74
1.73
1.65
1.64
1.51
1.54
1.48
1.42
1.22
1.24
1.24
1.48
1.49
1.37
1.52
1.56
1.61
1.64
1.60
W
1
-
.121
.085
.066
.093
.116
.090
.071
.070
.071
.073
.084
.085
.088
.085
.085
.074
.079
.088
.084
.076
.073
.076
.081
.089
.082
.108
.105
.107
.104
.112
.109
-
_
-
.
.
-
-
.
.
-
_
.
_
_
_
1STE
2
-
.118
.103
.097
.094
.105
.093
.090
.078
.081
.078
.090.
.093
.090
.093
.093
.089
.092
.076
.103
.096
.101
.095
.104
.135
.101
.102
.097
.105
.108
.114
.103
-
-
_
.
_
_
-
-
_
_
_
_
.
_
132
-------
TABLE A-18. FULL SCALE PERFORMANCE DATA
PHOSTR1P LPE SYSTEM - RENO/SPARKS, NEVADA
PH
FEED
11-22-76
11-23-76
11—24—76
11—25—76
11—26—76
11-27-76
11-28-76
11-29-76
11-30-76
11-31-76
1 9 A1 T-t
i.ttav,l~ / D
12-02-76
12-03-76
12-04-76
12-05-76
l 7_nt 7C
&£">UQ'>*/O
12-07-76
1 9 no 1C
1*— 08-76
12-09-76
12-10-76
12-11-76
12-12-76
12-13-76
12-14-76
12-15-76
12-16-76
12-17-76
12-18-76
12-19-76
12-20-76
12-21-76
12-22-76
12-23-76
12-24-76
12-25-76
12-26-76
12-27-76
12-28-76
12-29-76
12-30-76
12-31-76
01-01-77
01-02-77
01-03-77
01-04-77
01-05-77
01-06-77
01-07-77
01-08-77
01-09-77
01-10-77
01-11-77
01-12-77
01-13-77
01-14-77
01-15-77
01-16-77
01-17-77
01-18-77
01-19-77
01-20-77
01-21-77
01-22-77
01-23-77
01-24-77
01-25-77
01-26-77
01-27-77
01-28-77
01-29-77
01-30-77
FEED
PH
-
8.2
7.8
8.0
-
-
7.7
7 7
/ • /
7.8
7.5
7 5
* .5
8.4
8*
.4
8.8
8.8
-
-
-
P»
8.3
7.5
7.7
-
-
-
-
-
-
-
-
7.2
7.5
7.3
-
-
_
7.1
7.7
.
7.4
7.7
-
7.3
7.6
7.5
7.4
7.7
-
-
7.3
7.4
7.5
7.8
7.5
-
_
7.6
7.7
7.8
7.8
8.2
-
-
8.0
EFFLIl
PH 1
-
8.3
84
. 3
8.2
7.7
-
-
8.4
7 A
• O
7.7
7.5
7E
. J
8.1
B»X
8.6
8.2
-
-
-
8.3
7.6
7.8
-
-
-
-
-
7.4
7.3
7.1
-
-
7.1
7.5
7.3
7.5
7-7
-
-
7.3
7.4
7.5
7.5
7.3
-
-
7.3
7.7
7.2
7.3
7.3
-
-
7.3
7.6
7.2
7.8
7.9
-
-
7.7
IEHT MIXED LIQUOR 1 MIXED LIQUOR 2
PH 2 HIGH LOW HIGH LOU
-
7.3 - 7.3
8& ft n T \ ^ A 94
•t O.U l.i 7.9 7.2
8£ 7£ TO 1 £ •* a
•° '-o /.8 7.0 7.8
7 Q 7£ 7A t £ f L
'«' /.O /»4 /.o 7.4
7.8 7.4 8.2 7.4 7.8
„
-
7.8 7.3 7.8 7.3 7.6
- -
7.8 7.3 7,1 7.3 7.2
7.7 - 7.3 - 7.3
7.5 — 7.0 — 70
7E T C T 1 1£ T t
•3 /.S /.J 7.6 7.3
8.3 -
87 1C 7O ?1 '^E
•j /.O l.f 7.7 7.5
8.7 - -
8.2 7.2 7.4 7.3 7.6
-
-
-
-
7.9 7.6 7.4 7.5 7.3
7.6
7.8
-
-
-
-
-
-
-
-
-
7.4 - -
7.3 7.0 7.1 7.0 7.0
7.3 6.9 6.9 6.8 6.9
-
-
_
7.2 - -
7.7 6.9 6.7 7.0 6.8
7.4 - - -
7.6 7.2 6.8 7.2 6.9
7.9
7.1 7.0 7.2 7.1
- - -
7.5 -
7.6 7^0 6.9 .7.1 7..0
7.5 -
76 70 6.9 7.0 6.9
7.5 - - -
7.0 6.9 7.0 6.9
IE ^i 71 7n 7n
.5 7.1 '«! ' •" '*u
7.6 - -
7.5 -
7.4 7.0 7.0 7.0 6.9
7.5
- - -
- - - - -
7.4 -
7.7 6.9 7.2 6.8 7.0
7.4 -
7.8 7.2 6.9 7.2 6.9
8.0 -
7.0 7.2 7.0 7.2
-
7.8 -
STMFPB8
SUPERNATANT
7.8
7.7
8.1
_
7.8
-
7.6
7.3
7 J
8.3
8.2
8.4
8.8
7.7
7.5
7.6
-
-
-
7.2
6.9
-
6.8
7.2
7.0
7.4
7.1
7.0
7.1
7.0
7.0
7.1
7.3
7.3
-
~
7.4
7.4
7.2
7.6
8.3
"
7.5
133
-------
TABLE A-19. FULL SCALE PERFORMANCE DATA
PHOS1RIP LPE SYSTEM - RENO/SPARKS, NEVADA
BOD , COD, D.O. (mg/1)
DATE
11-22-76
11-23-76
11-24-76
11-25-76
11-26-76
11-27-76
11-28-76
11-29-76
11-30-76
11-31-76
12-01-76
12-02-76
12-03-76
12-04-76
12-05-76
12-06-76
12-07-76
12-08-76
12-09-76
12-10-76
12-11-76
12-12-76
12-13-76
12-14-76
12-15-76
12-16-76
12-17-76
12-18-76
12-19-76
12-20-76
12-21-76
12-22-76
12-23-76
12-24-76
12-25-76
12-26-76
12-27-76
12-28-76
12-29-76
12-30-76
12-31-76
01-01-77
01-02-77
01-03-77
01-04-77
01-05-77
01-06-77
01-07-77
01-08-77
01-09-77
01-10-77
'01-11-77
01-12-77
01-13-77
01-14-77
01-15-77
01-16-77
01-17-77
01-18-77
01-19-77
01-20-77
01-21-77
01-22-77
01-23-77
01-24-77
01-25-77
01-26-77
01-27-77
01-28-77
01-29-77
01-30-77
BODj INFLUENT
1 2
-
_
133
-
_
-
158
133
-
163
_
-
-
-
-
_
147
-
-
-
_
-
153
-
-
_
-
-
-
143
-
_
-
-
-
-
_
133
-
_
-
-
-
-
143
-
-
-
-
-
-
-
-
-
160
-
-
—
135
-
-
-
-
•_
163
_
_
-
-
_
_
165
_
-
-
_
-
_
130
_
_
-
_
_
155
_
-
-
_
-
140
160
-
_
_
-
-
_
_
133
_
_
_
80
-
_
163
-
-
_
-
201
_
177
-
_
193
-
163
_
145
-
-
_
BOD EFFLUENT
1 2
-
_
17
_
_
-
_
_
_
23
_
_
_
_
_
_
29
„
_
_
_
„
29
_
_
_
_
„
_
_
_
_
_
_
_
_
_
_
_
_
_
22
r
24
_
_
_
_
34
_
25
_
_
29
_
27
_
25
_
_
_
-
_
25
_
_
-
_
_
_
22
_
_
_
_
_
_
28
_
_
_
_
_
30
_
_
_
_
„
28
_
_
_
_
_
_
_
_
20
_
_
_
20
-
_
25
_
_
-
_
34
_
26
_
31
25
_
_
COD INFLUENT
-
_
-
_
_
-
-
_
-
_
_
_
_
_
_
_
_
_
_
_
_
_
_
_
_
_
_
_
_
_
_
_
_
_
_
_
—
_
_
_
_
—
_
_
_
_
_
_
_
_
_
-
_
_
_
_
_
_
D.O. STRIPPER
SUPERNATANT
-
_
_
_
_
_
_
_
-
_
_
_
_
_
_
-
2.4
_
_
_
_
_
_
_
_
_
_
_
3.1
_
_
_
_
_
_
_
_
_
_
_
_
_
_
134
-------
TABLE A-20. FULL SCALE PERFORMANCE DATA
PHOSTRIP LPE SYSTEM - RENO/SPARKS, NEVADA
TOTAL-PHOSPHORUS <«g/l)
DATE
11-22-76
11-23-76
11-24-76
11-25-76
11-26-76
11-27-76
11-28-76
11-29-76
11-30-76
11-31-76
12-01-76
12-02-76
12-03-76
12-04-76
12-05-76
12-06-76
12-07-76
12-08-76
12-09-76
12-10-76
12-11-76
12-12-76
12-13-76
12-14-76
12-15-76
12-16-76
12-17-76
12-18-76
12-19-76
12-20-76
12-21-76
12-22-76
12-23-76
12-24-76
12-25-76
12-26-76
12-27-76
12-28-76
12-29-76
12-30-76
12-31-76
01-01-77
01-02-77
01-03-77
01-04-77
01-05-77
01-06-77
01-07-77
01-08-77
01-09-77
01-10-77
01-11-77
01-12-77
01-13-77
01-14-77
01-15-77
01-16-77
01-17-77
01-18-77
01-19-77
01-20-77
01-21-77
01-22-77
01-23-77
01-24-77
1 01-25-77
01-26-77
01-27-77
01-28-77
01-29-77
01-30-77
FEED
_
-
-
_
-
-
-
-
-
-
_
-
-
-
_
10
11.2
6.6
9.4
8.4
-
-
-
8.0
7.0
10.0
-
-
-
-
-
-
-
-
-
13.2
8.4
10.0
-
-
-
9.2
7.8
-
-
8.6
-
-
10.2
11.1
8.2
10.8
8.4
-
.
10.2
10.8
9.6
9.1
8.6
-
—
9.8
8.8
8.1
8.3
10.1
-
9.3
EFFLOEHT AEROBIC RECYCLE 1
1 2 HIGH LOW
-
- -
- -
- _ _ _
168 88
-
-
-
-
-
208 80
-
- -
-
.. _ - _
3.3 3.5 184 120
6.1 7.2
3.1 2.6
3.3 3.9
2.5 3.7
.
_
-
2.9 4.3
3.8 3.8
2.8 3.4
-
_
-
-
-
_
-
_
- - - -
4.4 7.0
3.0 2.4
3.2 3.2 132 148
_
_
.
3.1 2.9
1.3 0.8 128 92
0.68 1.00
1.24 - -
1.16 0.88
_
_
1.88 2.12
1.72 1.72 172 172
1.64 1.24
0.68 0.88
2.48 2.00
- - -
. - - -
2.44 2.56
1.68 2.36 216 164
1.03 1.16
0.96 0.72
0.50 1.01
_
- - - -
0.56 0.87
1.14 1.27 240 230
1.01 1.21
0.72 0.69 -/18 -/18
0.94 0.64
_ «. — —
0.72 0.88 320/16 200/14
AEROBIC RECYCLE 2 ANOXIC RECYCLE STRIPPER
HIGH LOW HIGH LOW SUPERNATANT
-
-
-
- - - _ -
120 232 176
-
-
-
-
-
168 112 168 168
- - . . .
- - - . .
- - - -
- ....
116 88 160 176 19
43
27
19
- - 23
~ — » — -.
™ ~ * ~ *
~ — "-—•»
144 148 26
24
- 28
" ~" "" *~ *™
™ *"""""*"
"* •«.— •—
"
~
_
"
_ _ - - -
. — — — 28
128 116 216 144 41
-
50
144 76 160 164 39
- 18
mm — _ v JO
31
I
204 136 216 224 35
43
29
39
- - - -
31
248 168 112 212 35
41
30
36
~ — - —
~ I - - 34
270 240 240 220 34
29
-/17 -/13 -/46 -/66 34
30
- - - -
230/19 150/13 300/54 290/73 31
135
-------
TABLE. A-21. FULL SCALE PERFORMANCE DATA
PHOSTRIP LPE SYSTEM - RENO/SPARKS, NEVADA
ORTHO-PHOSPHORUS (ng/1)
DATE
11-22-76
11-23-78
11-24-76
11-25-76
11-26-76
11-27-76
11-28-76
11-29-76
11-30-76
11-31-76
12-01-76
12-02-76
12-03-76
12-04-76
12-05-76
12-06-76
12-07-76
12-08-76
12-09-76
12-10-76
12-11-76
12-12-76
12-13-76
12-14-76
12-15-76
12-16-76
12-17-76
12-18-76
12-19-76
12-20-76
12-21-76
12-22-76
12-23-76
12-24-76
12-25-76
12-26-76
12-27-76
12-28-76
12-29-76
12-30-76
12-31-76
01-01-77
01-02-77
01-03-77
01-04-77
01-05-77
01-06-77
01-07-77
01-08-77
01-09-77
01-10-77
01-11-77
01-12-77
01-13-77
01-14-77
01-15-77
01-16-77
01-17-77
01-18-77
01-19-77
01-20-77
01-21-77
01-22-77
01-23-77
01-24-77
01-25-77
01-26-77
01-27-77
01-28-77
01-29-77
01-30-77
FEED
5.6
5.8
6.4
7,6
7.0
8.2
7.2
6.8
7.4
6.8
8.0
7.6
4.6
7.0
7.0
-
6.0
6.2
-
-
-
7.8
5.8
7.8
6.4
6.6
7.4
6.6
7.6
6.4
6.4
6.6
6.8
7.4
7.0
7.2
5.8
6.0
5.7
6.4
5.6
6.1
6.4
6.6
EFFLUENT
1 2
0.60
0.60
0.80
1.76
0.82
1.72
2.88
1.96
1.88
2.16
2.96
4.96
2.20
2.20
2.50
1.16
2.80
2.40
_
-
3.8
1.8
2,6
1.7
0.90
0.40
0.56
0.80
1.32
1.36
1.60
0.56
1.72
-
1.84
1.44
1.04
0.32
0.36
0.76
0.28
0.20
0.28
0.44
0.52
0.52
1.36
0.52
1.84
0.48
1.36
3.76
2.80
2.88
2.36
2.96
5.44
1.50
3.50
3.10
-
3.40
2.30
-
_
4.4
2.0
2.5
2.4
0.80
0.70
1.13
0.60
1.36
1.40
1.12
0.76
1.68
2.04
1.78
1.08
0.60
0.96
0.80
0.76
0.44
0.32
0.40
0.52
HIGH
0.02
0.02
0.42
0.07
0.01
1.96
-
1.01
-
1.05
0.59
1.16
-
1.12
_
3.16
_
0.52
0.88
2.12
0.03
1.48
0.66
0.02
0.09
0.05
0.03
0.01
0.02
0.02
0.04
.03
HIKED LIQUOR AEROBIC RECYCLE
1212 ANOXIC RECYCLE
LOW HIGH LOW HIGH LOW HIGH LOW HIGH LOW
0.04 - 3.0 5.4 116
0.03 0.03 0.03 14.0 9.6 12.4 5.0 64 65
0.07 0.54 0.06 12.4 9.0 10.2 5.2 60 76
0.12 0.07 0.17 6.8 7.8 2.8 5.0 60 68
0.07 0.01 0.06 3.8 4.0 3,8 7.8 81 64
1.49 0.82 0.49 9.0 6.6 14/4 6.6 52 64
_ -
_
0.07 1.34 0.07 12.2 7.4 9.4 6.0 52 64
-
0.09 - 0.13 - 52 64
0.43 - 0.11 68
0.02 0.22 - 76
-
.
0.84 0.97 0.97 - 60 88
-
0.22 1.52 0.25 40 48
-
0.07 4.60 0.09 - 44 62
-
_
_
0.79 3.60 0.36 - 52 56
-
_
- - -
_
_
_
_
-
_
-
0.03 0.52 0.08 - - 52 58
0.09 1.20 0.10 - 50 68
_
_
-
0.01 0.04 0.03 - 84 78
-
0.03 0.01 0.11 70 94
-
0.02 0.76 0.03 - 66
_
0.03 0.37 0.04 78 88
-
0.04 0.02 0.05 72 73
-
0.04 0.08 0.05 - 56 72
_
-
0.03 0.03 0.03 - - 64 76
-
0.02 0.02 0.05 - 56 74
0.02 0.03 0.04 - 47 66
_
_
0.01 0.01 0.01 - 51 £2
- -
0.01 0.01 0.01 - 59 74
-
0.01 0.04 0.01 - 59 68
.04 .05 .05 - - - 62 82
STRIPPER
SUPERNATANT
29
23
25
25
24
23
-
27
-
16
24
16
_
17
37
25
23
26
25
9
26
25
37
40
24
38
31
38
39
28
42
36
46
42
34
43
30
37
31
33
28
31
136
-------
TAIL! A-22. PUT.l SCALE raRFCWAIBE DATA
nmrair in SYSTEM - ma/mas, NEVADA
TSS Cw/1)
HIIRO
DATE
11-22-76
11-23-76
11-24-76
• • •*•_*•£
11— ZS-/6
11-26-76
1 1 *Rt_9ll
11— ZB-76
11-29-76
11-30-76
11-31—76
12-01-76
12-02-76
12-03-76
12-04-76
12-05-76
12-06-76
12-07-76
12-48-76
12-09-76
12-10-76
12—12-76 •
12-13-76
12-14-76
12-15-76
12-16-76
12-17-76
12-18-76
12-19—76
12-20-76
12-22-76
12-23-76
12—24-76
12—25—76
12-26-76
12-27-76
12-21-76
12-29-76 .
12-30-76
12-11-76
01-01-77
01-02-77
01-03-77
01-04-77
01-05-77
01-06-77
01-07-77
01-08-77
01-09-77
01-10-77
01-11-77
01-11-77
01-13-77
01-14-77
01-15-77
01-16-77
01-17-77
OI-U-77
01-19-77
01-20r77
01-21-77
01-22-77
01-21-77
01-24-77
01-25-77
01-26-77
01-27-77
01-21-77
01-29-77
01-30-77
nsra
.
-
-
-
.
-
ill
115
100
121
109
106
101
111
19
113
1O4
&UQ
105
117
107
101
103
113
120
100
119
91
16
113
122
119
106
120
103
106
81
11
91
100
98
91
109
111
107
102
94
99
92*
14
110
106
113
114
104
91
99
113
m
i
16
20
-
14
20
-
20
19
22
14
26
16
23
23
7
20
11
11
23
29
27
27
32
12
15
13
23
22
25
22
7
19
18
12
14
22
17
20
25
11
I*
20
20
19
21
11
31
12
16
20
27
11
20
13
10
21
run
2
14
17
-
12
27
-
21
19
11
19
32
19
26
28
I
29
21
17
20
21
24
25
29
8
11
21
20
30
29
11
10
22
17
14
17
19
9
23
27
12
11
24
11
17
24
11
30
40
21
21
23
24
21
11
11
21
n
J
13
17
-
7
31
-
.
-
-
-
-
-
-
-
-
-
.
-
-
-
-
.
-
-
-
-
_
--
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
.-
.
.
LIQOfl
HIGH
-
l.OM
1.198
-
142
1,150
l.OM
161
1,086
1.088
1,132
1.116
l.OM
918
1,072
952
742
970
961
920
164
196
1,021
1,276
1,126
1,021
1,234
1,204
•42
1,074
1,111
1.131
1.131
1,160
1,111
1,064
1,052
1,126
1.090
1.100
1.180
.1.110
l.lV
1.050
1.114
1.066
1.232
1.206
1,234
1.011
1,011
1.026
1.142
1.062
1.110
1.128
* 1
LOU
.
1.100
1.412
-
982
1,400
1.212
718
1,274
1,088
1.132
1.330
1.170
1.222
1.271
1.164
.1.231
1.114
1.188
1.126
1.090
1.231
1.221
1.736
1.304
1.028
1.234
1.204
1,360
1,262
1.064
1.586
1.338
1.160
1,111
1,348
1,126
1,142
1,426
1,316
1,180
1,110
1,302
1,254
1,212
1.268
1,174
1.206
1,234
1,256
1.288
1.194
1.312
1.076
1.110
1.128
HIXBD MIXFO
Liqn
mo>
-
1,040
1,088
-
1,141
1,012
1,021
1,070
762
1.036
1.060
1,014
958
174
1.078
1,060
976
1,100
1,032
998
1,042
996
1,166
1,131
1.188
1.254
1.566
1.372
1.112
1.290
1.178
1.134
1,218
1,300
1.256
1.230
1,092
1,096
1,174
1.176
1.271
1.192
1.074
1,074
1,062
1,070
1.106
1.192
1.324
1.106
1.180
1406
1,184
1,098
1,262
1.170
tt 2 LIQUOR 3
LOU HICK LOW
-
1,236 1,060 1,082
1.294 1,046 1,160
-
2,970 970 1.306
1,284 1,044 1,124
1,216 -
1^250 -
l;224 -
1,036 -
1.060 -
1,250 -
1,196 -
1,030 -
1.364 -
1.250 -
1.346 -
1.344 -
1.330 -
1,270 -
1,191 -
1.334 -
1.471 -
1.570 -
1,501 -
1,254 -
1,566 -
1,372 -
1,456 -
1.736 -
' 1,311 -
1,222 -
1,492 -
1,300 -
1,256 -
1,434. -
1,206 -
1,224 -
1,394 -
1,394 -
1.271 -
1.192 -
1,396 -
1,400 -
1.216 - -
1,296 -
1.036 -
1,192 -
1.324 -
1,356 -
1.360
1.341 -
1,256 -
1,251 -
1,262 .-
1,170 -'
RECYC1
BIGS
-
6,196
7,311
-
3.626
6,650
6,052
5.450
1.272
5,436
5,311
1,722
7,290
6,341
6.784
7,064
6.7M
6,311
6,644
6,110
1,246
6,482
4,840
7,076
6.701
5,511
6,062
5,772
6,464
6,308
6,511
7,561
7,388
6.564
5,616
7,700
7.752
6,714
7,300
7,276
1,776
6.1M
7,564
7.308
6,660
6,432
7,534
6,664
6,410
7,376
6,121
3.576
7,513
7,936
6.064
6,656
t 1
LOU
•-
3.442
4,334
-
2,566
3,766
2,122
2,1312
4,072
5,436
5,311
3,022
4,054
3,650
3,770
3.541
3,424
1.174
3,094
3,072
3.122
3.464
4,020
5,320
4.448
3.511
6.062
5.772
4.092
4,05«
5,644
3., 921
4.596
6.564
5,616
5,712
5,376
2,688
3.521
4.316
4,776
6.186
4..7S6
5,214
6,560
6,620
i.232
1,664
6,480
6.544
6.272
4,408
6,352
5,860
6,064
6,656
RECYC1
HIGH
-
6,216
3,424
-
4,146
6,220
4,228
6,394
4,302
4,968
5,266
6,522
7,872
8,966
7,756
8.538
7,114
7,252
7,710
6,116
7,764
7,056
6.121
6.832
7.900
6,826
5,696
6,912
7.144
7,15.6
6,160
7,404
6,084
5,704
7,704
5,756
6.012
6,508
6,916
5,952
6.336
7.241
6.932
5.792
7.556
f.W>
6,464
6.044
6,376
8,100
8,160
7,030
7,712
6,794
6,646
,E 2
LOU
3,606
3,194
5,290
3.832
3,772
3,448
3,208
4,968
5,266
3,514
4,014
4,910
4,690
4,576
4,352
4,536
4,556
4,282
4,114
4,016
4,656
5,694
4,384
6,826
5,696
3,820
4.588
6,824
5.472
4,874
6,084
5,704
5,910
3,918
2.764
4,544
5,104
3,952
6,336
5,000
5,290
4,980
5.703
6.192
6,464
6.044
6.540
6,748
4,910
4.988
4,492
6,794
6,648
STRIPPER
RECYCLE 3 RETURN STRIP
HIGH LOU aiGB LOU SUPER
-
2,974 2,144 -
4,016 6,162 7,730 1,180 -
- - - 150
4,602 3,681 44
4,626 4.646 6,520 -
- - 46
- - - -
- - -
- - - -
62
10,610 -
- -
-
- - - -
-
-
7,760 49
45
6,188 8,160
-
-
- 70
6,300 9,160 105
- -
- -
330
11.950 11,820 -
- - 70
-
_
_
_
_
9,780 10.520 -
76
- - 61
.
-
-
57
8,250 8,560
-
- - - 56
-
- -
-
56
8.150 9,060
65
-
-
-
-
47
137
-------
TABLE A-23. FULL SCALE PERFORMANCE DATA
PHOSTRIP LFE SYSTEM - RENO/SPARKS, NEVADA
VSS (rag/1)
DATE
FEED
EFFLUENT
123
MIXED LIQUOR
HIGH LOW HIGH. LOU
HICK LOW
STRIPPER
RECYCLE 1 RECYCLE 2 RECYCLE 3 RETURN STRIP
HIGH LOW HIGH LOW HIGH LOW HIGH LOW SUP
11-22-76 -------- -- -- -- -- --
11-23-76 -------- -- -- •- - -
11-24-76 -------- - - -- -- -- --
11-25-76 ------ - -- -- - -- --
11-26-76 -------- -- -- -- -- --
11-27-76 -------- -- -- -- - - --
11-28-76 -------- -- -- -- -- --
11-29-76 - - - - 650 704 902 2,272 802 1,058 2,878 2,032 4,790 4,116 3,736 2,790 -
11-30-76 -------- -- -- -- -- - -
11-31-76 -------- -- -- -- --
12-01-76 - ---------------
12-02-76 -------- -_ -- -- - -
12-03-76 --- ---- __ -- -- _- _-
12-04-76 -------- _- -- -- -- --
12-05-76 30 23 28----- -- -- -- - -- 53
12-06-76 - - - - 922 1,120 844 1,016 -- -- -- -- --
12-07-76 -------- -- -- -- -- -- 49
12-08-76 -------- -- -- -- -- --
12-09-76 -------- -- - - - _- --
12-10-76 -------- -- -- -- -- --
12-11-76 - ------ -- -_ - _- --
12-12-76 100 28 25----- -- -- -- -- --
12-13-76 - 774 1,036 794 1,114 -- -- -- -- -- 46
12-14-76 ------- -- -- -- -- -- 47
12-15-76 - ------ -- _- -_ - -
12-16-76 - -----__-___-- - -
12*17-76 - ----- _________
12-18-76 ---- - - -- -_ -- .- __
12-19-76 -------- _- __ _- .- _.
.12-20-76 - -_-- __________
12-21-76 --------__-__ --
12-22-76 - ---- ________
12-23-76 - -- ----------- _ _ _
12-24-76 - -------------
12-25-76 ----- ------- - _ _ _
12-26-76 --- --.-_ .. __ _ _ v _ _ -_
12-27-76 88 14 17- --_ ------ ___
12-28-76 - - - 812 966 952 1,206 - - 5,560 3,260 5,592 3,792 - - - - 79
12-29-76 - -- -- __-__-. ---99
12-30-76 -------- .. __ __ __ _-
12-31-76 •- - -----_-_. - _ _ _ _
01-01-77 -- ----- -_ -_ -. __ _ _
01-02-77 90 16 23----- -- -- - -- -. 296
01-03-77 - - - - 681 1,000 911 1,144 ----------
01-04-77 -_-- --. _. __ _ _ _
01-05-77 -------- .. __ -_
01-06-77 -- ------- --._
01-07-77 -------- _ __ __ __
01-08-77 -. _-_ --. -_ __ _ _ __
01-09-77 -------- __ __ _ _
01-10-77 - - - - 884 1,072 994 1,146 - - 5,988 4,456 5,568 4,724 I I
01-11-77 - - - - - ______
01-12-77 79 20--- ------____ I0
01-13-77 --------------
01-14-77 -------------- I ~
01-15-77 - ------- __ -~~~_~
01-16-77 92 12 17----- -- - _. II I _ 5,,
01-17-77 - - - - 888 1,022 856 1,112 - 5,864 3,728 5,688 3,904 - - 6,780 7,280 -
01-19-77 ----- _ _ I ~ ~ ~ " " ~ ~,
01-20-77 - --- -_ ---"-"""I
01-21-77 --- - --___
01-22-77 --- ---. -__ -----
01-23-77 107-21- - -----III"" 50
01-24-77 - - 840 1,018 890 1,090 - - 5,820 5,164 5,052 5,164 I I I I _
01-26-77 -------- I. "I ~" " "
01-27-77 ------- --_. I " "
01-28-77 ---- ------ " ---
01-29-77 - ------ _ .. I" I" " "
01-30-77 ---------- " ----
138
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TECHNICAL REPORT DATA
(Please read Instructions on the re>crsc before completing)
. REPORT NO.
EPA-600/2-79-007
2.
.. TITLE AND SUBTITLE
BIOLOGICAL-CHEMICAL PROCESS FOR REMOVING PHOSPHORUS
AT RENO/SPARKS, NV
3. RECIPIENT'S ACCESSION NO.
5. REPORT DATE
February 1979 (Issuing Date)
6. PERFORMING ORGANIZATION CODE
. AUTHOR(S)
R. F. Drnevich
8. PERFORMING ORGANIZATION REPORT NO
.PERFORMING ORGANIZATION NAME AND ADDRESS
Union Carbide Corporation Reno/Sparks Wastewater
Linde Division for Treatment Facility
Tonawanda, New York 14150 431 Prater Way
Sparks, New York 89431
10. PROGRAM ELEMENT NO.
1BC822, SOS #3, Task C/07
11. CONTRACT/GRANT NO.
Grant #R-804931
12. SPONSORING AGENCY NAME AND ADDRESS
Municipal Environmental Research Laboratory-Cin., OH
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, Ohio 45268
13. TYPE OF REPORT AND PERIOD COVERED
Final - 1/76-3/78
14. SPONSORING AGENCY CODE
EPA/600/14
15. SUPPLEMENTARY NOTES
Project Officer: Edwin F. Barth, (513) 684-7641
16. ABSTRACT
demonstration project was initiated with the purpose of establishing
the capability of the PhoStrip system to remove phosphorus on a full scale activated
sludge system and compare these results to those obtained on a pilot scale system.
This process employs the capability of activated sludge to take up and release phosphori
as a result of being cycled between aerobic and anoxic conditions. During the aerobic
period in the aeration basin the phosphorus in the wastewater is removed by the biomass
The sludge is then separated from the phosphorus-free wastewater in the secondary clari
fier. A portion of the return sludge from the clarifier is pumped to an anoxic strippe
tank where the phosphorus is released. This phosphorus -containing water is then separa
ted from the sludge either through further thickening of the sludge or through elutria-
tion. The supernatant from the anoxic zone is treated with lime to precipitate the
phosphorus and the sludge from the anoxic zone is returned to the aeration basin. The
pilot and full scale testing was performed at the Reno/Sparks Joint Water Pollution
Control Plant located in Sparks, Nevada. The pilot scale system consisted of a 0.11
» /hr diffused air activated sludge system. This system was designed to produce optimun
performance with the elutriation mode of separating the phosphorus from the sludge in
the anoxic zone (stripper tank) . The full scale system consisted of a temporary modi-
tication of the Reno/Sparks plant. Treating one-third of the plant flow (25,000 m /d)
was first tested using the thickening mode of separating phosphorus from the sludge in
T.a*or two-thirds Of t.hft plant flnw (Sl^nnn mS/rl) wag 1-T-Patgrl iit-i li
17. the elutriation method.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.IDENTIFIERS/OPEN ENDED TERMS
c. COS AT I Field/Group
*Wastewater
*Phosphorus cycle
Biochemistry
Bioengineering
*Anoxic stripping
Counter-current flow
Chemical precipitation
*Side stream concentration
PhoStrip
13B
18. DISTRIBUTION STATEMENT
Release to Public
•HMBMMBMMMMMB^BBMBMMMBMHB^B
EPA Form 2220-1 (Rev. 4-77)
19. SECURITY CLASS (This Report)
Unclassified
151
20. SECURITY CLASS (This page)
Unclassified
22. PRICE
139
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