EPA-660/2-74-039
JUNE 1974
Environmental Protection Technology Series
Catalyzed Bio-Oxidation and Tertiary
Treatment of Integrated Textile
Wastewaters
Office of Research and Development
U.S. Environmental Protection Agency
Washington, D.C. 20460
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RESEARCH REPORTING SERIES
Research reports of the Office of Research and
Monitoring, Environmental Protection Agency, have
been grouped into five series. These five broad
categories were established to facilitate further
development and application of environmental
technolpgy. Elimination of traditional grouping
was consciously planned to foster technology
transfer and a maximum interface in related
fields. The five series are:
1. Environmental Health Effects Research
2. Environmental Protection Technology
3. Ecological Research
U. Environmental Monitoring
5. Socioeconomic Environmental Studies
This report has been assigned to the ENVIRONMENTAL
PROTECTION TECHNOLOGY series. This series
describes research performed to develop and
demonstrate instrumentation, equipment and
methodology to repair or prevent environmental
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.
EPA REVIEW NOTICE
This report has been reviewed by the Office of Research and
Development, EPA, and approved for publication. Approval does
not signify that the contents necessarily reflect the views and
policies of the Environmental Protection Agency, nor does
mention of trade names or commercial products constitute
endorsement or recommendation for use.
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EPA-660/2-7^-039
June 197^
CATALYZED BIO-OXIDATION AND
TERTIARY TREATMENT OF INTEGRATED
TEXTILE WASTEWATERS
By
Alvin J. Snyder
Thomas A. Alspaugh
Project 12090 HLO
Program Element IBB036
Roap/Task 21 AZT 006
Project Officer
*
Thomas N. Sargent*,
Southeast Environmental Research Laboratory
College Station Road
Athens, Georgia 30601
Prepared for
OFFICE OF RESEARCH AND DEVELOPMENT
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON, D.C. 20*»60
For sale by the Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402 - Price $1.65
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ABSTRACT
This report describes the observations from preliminary
studies and pilot plant operations that were initiated to
upgrade the waste effluent of an integrated textile dye
mill. The biological pilot plant was designed to utilize
activated carbon on the basis that the presence of carbon
enhances bio-degradation.
To meet the proposed water standards, tertiary treatment
of the effluent was also necessary. Two methods of attain-
ing better water effluent were investigated. A conventional
method, the addition of an alum system, with alum recovery
was added to the biological treatment system. Although the
effluent quality improved, trace color remained in the super-
natant. An adsorbent resin system was tested and found effec-
tive in upgrading the waste effluent to recreational standards,
The results of preliminary studies and the pilot plant indi-
cate that carbon catalysis enhances biological degradation,
and satisfactory tertiary treatment can be achieved with an
alum and resin system..
This report was submitted by Cone Mills Corporation, in
partial fulfillment of Grant Project #12090 HLO by the Office
of Research and Development of the U.S. Environmental Pro-
tection Agency.
ii
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CONTENTS
Page
ABSTRACT i I
LIST OF FIGURES iv
LIST OF TABLES v!
ACKNOWLEDGMENTS vii
SECTIONS
I. CONCLUSIONS 1
II. RECOMMENDATIONS 3
III. INTRODUCTION k
IV. PRELIMINARY STUDIES 11
V. DESCRIPTION AND OPERATION
OF PILOT PLANT 31
VI. PILOT PLANT DATA 37
VII. KINETIC EVALUATIONS 66
VIII. FULL-SCALE MODEL 70
IX. REFERENCES 81
X. GLOSSARY 82
iii
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FIGURES
Number Page
1 Location Map, Cone Mills Corporation 5
2 Effects of Carbon on Biodegradation Batch
Aeration (TOD) 13
3 Effects of Carbon on Biodegradation Batch
Aeration (Color) 14
k Comparision of Catalyzed and Non-Catalyzed
Biological Reactors 15
5 Adsorption Rates of TOD on Various Carbons -
Cone Mills' Effluent 17
6 Adsorption Rates of Color on Various Carbons -
Cone Mills' Effluent 18
7 Color and TOC Equilibrium Isotherms 20
8 Phosphate and Color Removal vs. Alum
Concentrations 21
9 Resin Pilot Plant Performance 28
10 Resin Treatment of Alum Clarifier Effluent 29
11 Biological Pilot Plant 32
12 Alum Pilot Plant 34
13 Resin Pilot Plant 35
14 Biological Pilot Plant Overall Performance 38
15 COD Content - Percent Occurrence 46
16 BOD Content - Percent Occurrence 47
IV
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FIGURES (cont.)
Number Page
17 Color Content - Percent Occurrence 48
18 Suspended Solids Content - Percent Occurrence 49
19 NH^ Content - Percent Occurrence 50
20 Phosphate Content - Percent Occurence 51
21 pH - Percent Occurence 52
22 Alum Clarlfler Influent Color vs. Clarifler pH 54
23 Alum Clarifier Effluent Color vs. Clarlfler pH 55
24 Tltratlon Curves of Lagoon Waste 57
25 Carbon Adsorption of Color During Alum
Flocculation 59
26 Effect of Chlorination on Color Removal for
Alum Treated Clarifier Waste 60
27 Resin Treatment of Clarifier Effluent
(FR-56 Resin) 62
28 Pilot Plant Performance (FR-56 Resin) 63
29 Biokinetic Rate - Reactor 1 67
30 Biokinetic Rate - Reactor 2 68
31 Biokinetic Rate - Reactor 3 69
n
32a Biological System 71
32b Alum System 72
32c Resin Adsorption System 73
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TABLES
I
Number Page
1 Cone Mills' Treatment Effluent Characteristics 6
2 Chemical Flocculation - Laboratory Study 19
3 Alum Precipitation System 23
4 Alum Regeneration Losses - Laboratory Study 24
5 pH Effect on Alum Precipitation 26
6 Biological Pilot Plant - Optimum Performance 39
7 Comparison of Pilot Plant and Main Plant
Effluents 40
8 Biological Pilot Plant Data - Phase I 42
9 Performance of Biological Reactors 44
10 Average Performance of Alum Pilot Plant 53
11 Color Removal at Various Clarifier Effluent
pH's (Pilot Plant) 56
12 Resin Performance Summary - FR-56 Resin 64
13 Heavy Metal Concentrations in Return
Biological Sludge 65
14 Projected Effluent Quality 76
15 Estimated Capital Cost 77
16 Estimated Operating Cost 78
17 Annual Costs 80
VI
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ACKNOWLEDGMENTS
The ideas and the development of the technical concepts
for upgrading the Cone Mills' effluent were a cooperative
effort of Alan Molvar and Clarke A. Rodman of Fram Corporation.
Supervision and management of the pilot plant were con-
ducted by Henry Moreau and Philip Virgadamo. On-site
sampling and analysis conducted by Richard Harris and
Frederick Keenan of Fram Corporation are gratefully ac-
knowledged.
The cooperation and assistance of Arthur Toompas of
Cone Mills Corporation are gratefully acknowledged.
The significant aid of Susan Anderson of Fram Corporation
in the organization, preparation, and writing of this re-
port is acknowledged. Also, the efforts of Doris Peck in
preparing the original manuscript are gratefully acknowledged.
vii
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SECTION I
CONCLUSIONS
Over a twelve month period, beginning in September 1971, a study
was made of the methods by which an existing secondary waste treatment
plant for an integrated textile mill could be upgraded to meet more
stringent water standards.'
Based on the results of the study conducted at the Cone Mills Corpor-
ation, Greensboro, North Carolina facility, the following conclusions
have been reached:
1. The presence of carbon in aerated biological reactors
enhances the rates of biological degradation of color
bodies and organic substrates as experienced in the
textile wet processing operations.
2. Alum treatment of biologically treated effluent reduces the
total organic carbon content and color by about one-third,
but alum concentrations of 300 - 400 milligrams per liter
are required.
3. Alum regeneration is possible by acidification of alum
sludge with sulfuric acid to a pH of 2.0.
k. Alum regeneration is necessary to make the process
economically feasible.
5. Ten percent make-up alum is required to offset losses
in the alum recovery system.
6. Color removal is reduced when the pH of the alum system
falls below 5.0.
7. Adsorbent resins are effective in removing dissolved
residual organic color bodies.
8. Regeneration of adsorbent resin is effectively accomplished
by elution with warm caustic solution and the eluate can
be acceptably disposed of via recycling.
9. Resin treatment can be effective as a tertiary treatment method
either before or after an alum treatment system.
10. Regular sludge wasting is necessary for good color removal
and reduces heavy metals concentration in the sludge.
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11. No reductions in ammonia nitrogen were observed because of
the solubility of the ammonium compounds.
12. High levels of chlorine significantly reduce the color of
the alum treated waste.
13. The estimated capital cost for a 3,785 cubic meter per day
plant is $85^,500 for the biological system; for the alum
system $30J»,500; and for the resin system $236,500. The
total installed cost including contingencies, land and
contractor fees is $1,490,000.
14. The operating expenses based on chemical costs, utilities,
and labor for the plant would be $0.28 per 3.79 cubic meters
waste treated.
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SECTION II
RECOMMENDATIONS
1. As a result of the laboratory studies and pilot plant
operations, efforts should proceed toward a full-
scale demonstration of a carbon catalyzed system
with stage aeration.
2. In general, the presence of carbon in a biological system
enhances biological degradation, and the addition of carbon
to an existing aeration basin (lagoon) should be evaluated
as a method of increasing effluent quality.
3. A carbon catalyzed system with stage aeration appears to
treat biodegradable wastes efficiently, and the
effectiveness on municipal wastes should be investigated.
4. A full-scale carbon catalyzed system should be demon-
strated with alum and resin systems for tertiary treat-
ment of textile dyeing wastes.
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SECT I ON III
INTRODUCTION
Cone Mills Corporation, located in Greensboro, North Carolina (see
Figure 1), is a manufacturer of finished textile fabrics. The com-
bined wastewater discharged into the North Buffalo Creek is generated
from several sources: 1) an integrated denim mill; 2) an integrated
flannel and other flat goods mill; and 3) a printing and finishing
mill. The treatment for the dyes and finishing chemicals in the Cone
Mills' effluent was found to be insufficient to meet the new proposed
North Carolina State water quality standards.
The amount of wastewater from the Cone Mills' treatment plant varies
from 11,355 to 13,626 cubic meters per day (m3/day). The waste-
water content fluctuates according to the type of process and dye used.
A successful waste treatment program had to consider several types
of processes as well as a variety of dyes. The average wastewater
characteristics, the anticipated effluent characteristics after treat-
ment, and the effluent standards desired by the North Carolina Depart-
ment of Water and Air Resources are presented in Table 1.
Cone Mills had an existing on-site secondary waste treatment plant,
which discharged to the nearby North Buffalo Creek. The wastewater
was handled within this existing system in the following manner:
The waste first entered aerobic holding ponds with a combined
detention time of 48 hours. The wastewater was biologically
degraded in this step by mixing with 10% domestic sewage for
seeding purposes, and fed into a 24 hour detention aeration
basin. This basin operated at a suspended solids (SS) level of
12,000 - 14,000 milligrams per liter (mg/1). The waste was
settled for four hours in clarifiers and the sludge was recycled
to the aeration basin. Aeration and mixing were provided by
mechanical aerators. Waste sludge was handled under contract by
the Greensboro Municipal System with a maximum allowable waste
volume of 114 m3/day. The clarifier effluent received further
clarification in a newly built (Spring, 1971) lagoon with a five
to seven day detention time. The liquid effluent was chlorinated,
reaerated for 45 minutes for saturation, and then discharged into
the creek.
In the past, this level of treatment had been sufficient for creek dis-
charges; however, Buffalo Creek will soon become one of the water
sources of a reservoir formed by the Jordan Dam across the Haw River.
The resultant proposed water quality standards for Cone Mills' dis-
charge require 99% five day biochemical oxygen demand (BODj) reduction,
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Figure 1
Location Map
Cone Mills Corporation
Greensboro, North Carolina
CONE MILLS
CORPORATION
BUFFALO
LAKE
CONE BLV
NORTH
BUFFALO
CREEK
GREENSBORO
CENTER
SCALE IN MILES
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Table 1. CONE MILLS' TREATMENT EFFLUENT CHARACTERISTICS
Parameter
Volume, nr/day
pH
BODr, mg/1
COD, mg/1
SS, mg/1
Color
Phosphate,
mg/1
Total Kjeldahl
Nitrogen, mg/1
Raw waste
11.4 - 15.1
12 - 13
600 - 1000
1200 - 2000
100 - 200
Varied
blue/black
Not
recorded
Not
recorded
Present
secondary
11.4 - 15.1
7.5 - 8.0
25 - 85
200 - 300
20 - 50
Light green
to yellow
jf
5 - 10
5-10
New tertiary
under construction
estimated
11.4 - 15.1
7.5 - 8.0
10-50
200
5-20
Yellowish -
green
SI ightly lower avg.
but still 5-10
5 - 10
North Carol ina state
desired
standards
Not specified
7.5 - 8.0
5
30
0-10
Clear - no
visible color
Approximately
zero
Approximately
zero
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a 99+% phosphate-reduction, a 99+% Kjeldahl nitrogen reduction, a
38% chemical oxygen demand (COD) reduction, a 96% suspended solids
reduction, and virtually 100% color removal (see Table 1). The
same problem of upgrading the performance of the existing Cone Mills'
treatment plant to meet these high discharge quality standards within
possible economic bounds will be facing many other large textile pro-
ducers.
BIO-CATALYSIS THEORY
The large surface area of activated carbon, as much as 1,000 square
meter/gram, and the chemical functionality of the available surface
are the major factors responsible for activated carbon's adsorptive
action. This surface area is made up of micropores having diameters
in the order of 10 - 1,000 Angstrom units. A combination of the action
of Van der Waal's force of attraction and some chemical reactivity
on the large surface area is responsible for the adsorbent properties
of carbon.
Because of the relatively large size of bacterial cells (greater than
5,000 Angstrom units), a mechanism involving migration of bacteria
into the carbon interstitial spaces is improbable. Bacteria do,
however, have the ability to produce enzymes which function outside
their cellular boundaries. The exo-enxymes are produced within the
cell and then excreted by the organism to the surrounding media. Exo-
enzymes function independently of the bacteria that produced them
and are mainly digestive or hydrolytic In nature.
Exo-enzymes, being much smaller than a bacterial cell probably in
the order of 10 Angstrom units, could easily diffuse into and out
of the microporous structure. It is reasonable to assume that an
enzyme-substrate relationship is possible within the carbon structure,
i.e., *a specific enzymatic substrate can be formed.
The carbon adsorption of the substrates and diffused enzyme inter-
action would act to provide a higher concentration of reactants, and
thus allow a greater degree of intermolecular contact. It can be
speculated that this higher concentration would result in an increased
rate of degradation by the enzyme; hence, carbon would be behaving
as a catalyst to biodegradation.
BIOLOGICAL REACTOR THEORY
The utilization of smaller multi-staged aerated lagoons rather than
a large single basin results in a more efficient biological system
capable of producing a higher quality effluent. The biokinetics of
aerated activated sludge systems confirmed the observations.
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Biological degradation of organic material is achieved by the process
known as biological oxidation, in this process under aerated
conditions, the organic material, or substrate, is broken down by
enzymatic action to a form that can be utilized by the organism for
cellular metabolism. The end products are carbon dioxide, water, new
biological organisms and inert cellular material. >
The rate of biological degradation for first order reactions is
directly proportional to the concentration of the substrate at a
given concentration of biological organisms' as shown in the relation
below:
d S « S (1)
d t
where: S = substrate concentration
t = time
In general, it is apparent that for a given concentration of biological
organisms, higher rates of removal may be achieved using higher sub-
strate concentrations. Therefore, a biological waste treatment
system capable of increasing the concentration of substrate by its
physical design within the aerated basin is capable of degrading
more substrate per unit basin volume.
RESIN ADSORPTION THEORY
Biological and chemical treatment of organic wastes often result
in an effluent that has only trace amounts of color (less than 50
platinum-cobalt color units), yet the nature of the color
may not meet aesthetic water quality standards. As a result, treat-
ment after biological and chemical treatment may be necessary. Treat-
ment by means of adsorbent resins removes residual color to a level
invisible to the naked eye.
Adsorbent resins are composed of hard, insoluble, polymeric particles
that possess a high surface area and porosity. Various compounds in
solution, including organic materials, are attracted to the resin sur-
face by the action of Van der Waal's forces. A weak bond is formed
between the resin structure and the adsorbed compound which can be
broken by adverse chemical conditions such as high pH.
-------
The introduction of caustic to the adsorbent-adsorbate complex
results in severance of the bond and the release of the adsorbate
to the caustic solution.
Such a process is applicable to the removal from solution of trace
color. The color body is readily adsorbed by the resin, rendering
a colorfree solution. When the resin has adsorbed its capacity of
color bodies, it .is regenerated by the addition of caustic solution.
The resultant colored caustic regenerate solution is of relatively
small volume (U) and is treated in the biological lagoons for
eventual color degradation.
CHEMICAL PRECIPITATION AND COAGULATION THEORY
Soluble organic materials can generally be removed from waste-
. water by a carbon catalyzed system. However, certain inorganic
materials are not biologically degradable. Phosphates are a
prime,example. Thus, a further step in a waste treatment system
becomes necessary to achieve high levels of effluent quality.
' -i
Chemical treatment of biologically degraded effluent will remove
soluble and colloidal contaminants such as phosphates and an
unsettled biological mass. This treatment process acts in two
ways. First, the addition of chemicals such as alum causes
some normally soluble materials such as phosphates to precip-
itate from solution due to the formation of insoluble chemical
compounds. Secondly, the resultant suspended solids along with
other colloidal particles are removed via chemical coagulation/
precipitation.
Chemical coagulation of colloids and suspended solids is achieved
by two processes: 1) the agglomeration of colloidal particles that
are held in suspension by electrostatic forces; and 2) the chemical
formation of large solid masses that capture suspended solids and
cause them to settle out of solution. Coagulating agents (e.g.,
alum and ferric chloride) provide the charged ions that neutralize
the electrostatically charged colloids. The agglomerated colloidal
particles along with large suspended particles are captured by heavy
aluminum and ferric hydroxides and rapidly settle out of solution.
PROJECT OBJECTIVES
The project was designed to evaluate approaches that would enable
Cone Mills to meet the proposed water quality standards dictated by
the construction of the Jordan Dam on the upper Haw River. A lit-
erature search and laboratory study were the basis of the preliminary
work done to achieve these goals. On-site pilot plant scale studies
were evaluated for their technical and economical feasibility.
-------
The first recommendation involved the use of a surface active agent
(activated carbon) added to a typical activated sludge biological
system to catalyze biodegradation, thus requiring shorter detention
times in the aeration basins.
The use of a coagulant such as alum for removing phosphates and
reducing the color and organic content of the biologically
treated waste effluent is a standard approach. The regeneration
of the coagulant (not a standard approach) was another aspect in
reducing operating costs and in reducing the volume of waste sludge
for disposal.
A residual yellowish-green detectable coloration of the treated
effluent persisted after carbon catalyzed biological treatment
and alum flocculation and coagulation. Hence, to achieve an essen-
tially colorless effluent, synthetic resin adsorbents were investi-
gated as polishing agents after biological treatment alone, and
after biological plus alum treatment.
TO
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SECTION IV
PRELIMINARY STUDIES
Preliminary studies were conducted in three areas:
Carbon Catalysis
Floe Studies £ Alum Regeneration
Alum Selection
These investigatory phases were the basis for the selection of a
commercial carbon for use in the pilot plant; the most efficient
coagulant for removing phosphates and reducing color at Cone
Mills; and the type of resin to be used to treat the effluent from
the biological clarifier of the catalyzed biological system. Data
collected also indicated the amount of sulphuric acid necessary
for the alum regeneration as well as being the foundation for com-
parative analysis of the effectiveness of different resins tested.
CARBON CATALYSIS
The prospect of using a carbon catalyzed biological system was
investigated on two separate occasions (June 3, 1970 and April - May,
1972) in a series of tests with Cone Mills' plant waste. In 1970,
Cone Mills sent Fram Corporation two 55~gallon drum samples of the
raw effluent (before biological treatment) and two 55-gallon drum
samples of the final clarifier effluent (after biological treat-
ment) for analysis.
Each waste was biologically degraded in a continuous aeration batch
reactor with and without carbon. The concentration of granular
carbon was 40 grams per 3000 mi 111 liters (ml) of waste. After six
days' aeration, the degraded waste was replaced with fresh waste and
aeration continued. The supernatant, total oxygen demand (TOD), and
color were measured at various intervals. TOD was chosen as an index
at this point because it represents a close relationship to BOD^,
and it can be determined in five minutes as compared to five days
for
Using a variable grating spectrophotometer, the light absorbance is
measured at three wavelelengths - 350,^50, and 550 millimicrons. If
the light absorbance is greater than the instrument scale, the sample
is diluted and a dilution multiplier is used to calculate the ab-
sorbance. The Fram color unit (FCU) is the sum of the corrected
light absorbance at these three wavelengths. Although not correlative
from sample to sample, the platinum-cobalt color units are in the
magnitude of 1,000 times that of the Fram color unit.
11
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The biological treatment of the raw influent from the non-catalyzed
reactors yielded an equilibrium TOD concentration nearly equal to
the final clarifier effluent of the same system, suggesting that a
certain portion of the waste is difficult to degrade biologically.
The presence of carbon, however, allowed nearly complete degrada-
tion of the organics (see Figures 2 and 3)-
Specifically, the raw effluent in the non-catalyzed reactor reached
an equilibrium TOD value representing 6$% reduction in 48 hours. The
color concentration dropped k$% in a period of 72 hours. The carbon
catalyzed reactor experienced TOD and color reductions of 90% In the
same time periods. This represents an additional 21% TOD and 41%
color removal due to the presence of carbon. Figures 2 and 3 in-
dicate the changes in TOD and color concentrations with respect to
elapsed time. In all cases, the presence of carbon in the biological
reactor greatly enhanced the removal of contaminants by effecting
an increased kinetic rate of organic removal. The final equilibrium
TOD and color concentrations were also much lower than the non-
carbon counterparts.
The beneficial effect of carbon on biological systems was further
confirmed in an on-site laboratory investigation in April and May
of 1972 by Cone Mills' personnel. The carbon evaluation was con-
ducted with four 3.78 liter containers. Two of these containers
contained 20 grams of carbon. The others were used as control units
and contained no carbon. One set made up of a container with carbon
and a container without carbon was vigorously aerated. Another
similar set of two more containers was moderately aerated. The fil-
tered reactor effluent was measured each day to determine the effect
of carbon. Fresh raw waste was added daily to each reactor.
After six test days, the aerated reactors experiencing the highest
aerations were discontinued because of comparably high reactor
colors. The moderately aerated reactors revealed that carbon
definitely improved the biological degradation of the color bodies
present in the raw waste (see Figure 4). Throughout the seven week
test period, the reactor containing carbon gave consistently lower
effluent colors. The reactor with carbon gave an average color of
0.173 Fram color unit, while the control reactor without carbon
yielded a much higher color of 0.296 Fram color unit.
SELECTION OF CARBON
Selection of carbon to be utilized in the pilot studies depended
largely on two factors. First, the carbon particle size had to be
large enough so that the carbon would not be lost in the reactor
effluent and yet provide a reasonable amount of surface area.
Second, since commercial grades of carbon vary in their adsorbent
capacity, a carbon with a high efficiency in TOD reduction and
color removal had to be determined.
12
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Figure 2
700
600
500
400
o
o
300
200
100
Effects of carbon on blodegradation
batch Aeration
(Nuchar WV-G carbon)
Waste of June 3, 1970
RAW WASTE
CLARIFIER EFFLUENT
RAW WASTE & CARBON
CLARIFIER EFFLUENT
CARBON
CURVE A
CURVE B
CURVE C
CURVE D
24
48 72 96
TIME, hours
120
144
13
-------
Figure 3
0.700
QC
O
Of.
LU
Q.
0.600
0.500
0.400
0.300
0.200
0.100
Effects of Carbon on Biodegradation
batch Aeration
(Nuchar WV-G Carbon)
Waste of June 3, 1970
CURVE A
CURVE B
CURVE C
CURVE D
RAW WASTE
CLARIFIER EFFLUENT
RAW WASTE & CARBON
CLARIFIER EFFLUENT & CARBON
48 72
TIME, hours
\k
-------
Figure 4
a:
o
_i
o
o
LU
Ul
0.400
0.300
0.200
0.100
Comparison of catalyzed and non-catalyzed
biological Reactors
CARBON
10
20
APRIL
30
20
30
MAY
-------
A carbon of 12 x 40 mesh satisfied the parameters of the first
condition. Several tests were performed to determine the efficiency
of Nuchar WV-G, Darco, and Norit II in TOD reduction and color re-
moval to meet the parameters of the second condition.
In the lab on September 14 and 15, 1971, five grams of each type of
carbon were added to 1,000 ml of aerated raw waste adjusted to a
pH of 7-8. Samples of the supernatant were withdrawn periodically,
filtered, and measured for color and TOD. Nuchar WV-G and Darco
carbons were found superior to Norit II in both color and TOD re-
moval (see Figures 5 and 6). Nuchar and Darco demonstrated equal
TOD adsorbent capacities. Darco carbon initially had a higher color
removal rate; however, the total color removal was equal after ex-
tended periods of time (greater than 24 hours). Nuchar WV-G carbon
was utilized for pilot plant studies.
CARBON ISOTHERMS
The equilibrium isotherms for Nuchar WV-G and Cone's raw waste
were determined in laboratory shaker tests on September 15, 1971.
Various quantities of carbon were added to 200 ml aliquots of raw
waste adjusted to a pH of 7.8. The color and total organic carbon
(TOC) concentration were measured before and after 65 hours' contact
time under agitated conditions. Total organic carbon was used as an
indicator of organic matter present. The percent removals for both
color and TOC were found to increase until the optimization of
approximately 8 to 9 grams per liter carbon concentration. A carbon
concentration of 5 grams per liter was considered to be reasonable for
the pending pilot plant study.. Color and TOC percent removals at this
concentration were 95 to 98% of the maximum removals observed (see
Figure 7)-
SELECTION OF FLOCCULANTS
Prior to pilot plant studies, tests were performed to determine the
most efficient coagulant to remove phosphates and reduce color. A
series of experiments were run involving alum, ferric chloride and
lime to study the extent of phosphate and color removal. Table 2 is
a summary of the results obtained. Alum was found to be the most
effective flocculant, ferric chloride removed little color, and lime
had only limited color removal, regardless of concentration.
Figure 8 illustrates the observed color and phosphate removal versus
concentration of alum. A range of alum concentration was evaluated
in the pilot system to determine the optimum amounts for maximum
efficiency. On September 24, 400 mg/1 were added to the biological
pilot plant system in the alum clarifier. There were periodic
difficulties with floating solids. After a week of this operation,
16
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Figure 5
Adsorption rates of TOD on various carbons
Cone Mills' Effluent
1000
o
o
800
660
400
200
NORIT II
o NUCHAR WV-G
* DARCO
NORIT II
DARCO
I
I
20 min. 40 tnin. 1 hr.
10
20
30
40
50
TIME
-------
o.ao :
13
O
O
_J
O
O
Figure 6
Adsorption rates of color on various carbons
Cone Mills' Effluent
0.25 -2-
0.20
0.15
0.10
0.05
TIME
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Table 2. CHEMICAL FLOCCULATION - LABORATORY STUDY
Treatment
Alum
Untreated
100 mg/1
200 mg/1
300 mg/1
400 mg/1
500 mg/1
Ferric Chloride
Untreated
100 mg/1
200 mg/1
300 mg/1
400 mg/1
500 mg/1
Lime
Untreated
100 mg/1
200 mg/1
300 mg/1
400 mg/1
500 mg/1
Initial pH - 7.8
^ 1 M I ^ * A 1 X**^l* *»^0* 4» A # 4%M
PH*
6.6
6.6
6.2
6.0
5.6
5.6
8.0
8.3
7-9
7-5
6.5
6.2
11.2
.5
.6
.6
.7
.8
. » C C m«/l
Ortho-
phosphate12
0
13
18
59
100
100
0
1
10
27
82
100
0
56
69
73
,83
% Color
removal0
0
6
20
53
85
93
0
0
0
0
0
72
0
33
49
49
47
49
^M
CODd
0
0
k
16
26
28
0
4
6
9
24
38
0
4
4
6
4
6
Initial color = 0.75 FCU, all samples analyzed after filtration with
1.2 micron membrane
Initial concentration - 935 mg/1, all samples analyzed after filtra-
tion with 1.2 micron membrane
19
-------
Figure 7
Color and TOC
equilibrium isotherms
Nuchar WV-G
100
90
o
z:
UJ
a:
CJ
OL
80
70
60
50
I
I
4 8 12 16
CARBON CONCENTRATION, g/1
20
2:0
-------
Figure 8
TOO
80
o
UJ
cc
H-
z
UJ
o
UJ
o.
60
40
20
Phosphate and color removal
versus
alum concentration
pH 5.6 - 6.6
ORTHO-
PHOSPHATE
I
100 200 300
ALUM CONCENTRATION, mg/1
400
500
21
-------
the alum was mixed with the clarified biological system effluent in
a separate tank before being sent to an alum clarifier. This reduced
but did not eliminate the problem of occasional floating solids.
On October 15, 1971, the alum concentration was reduced to 250 mg/1.
Table 3 shows the TOC and color reductions produced by the alum
system. This system consistently produces an effluent with less than
one mg/1 ort1ophosphates, and reduces the TOC and color by about
one-third.
After the analysis of the effluent from the alum precipitation system
with 250 mg/1, it was recommended that the alum concentration be raised
to 300 mg/1 in mid-January and continued at that level until the
completion of the pilot plant studies.
ALUM RECOVERY
Laboratory and pilot plant testing indicated that a system that would
regenerate the alum sludge to a dissolved state by adding sulphuric
acid and recycling the recovered alum back into the alum system
would be more efficient. With the present cost of alum per pound
being significantly higher than the cost of sulphuric acid, this
method of alum regeneration would also have economical benefits.
tj
In a laboratory study, a sample of the biological clarifier effluent
from the pilot plant was treated with 500 mg/1 to simulate the
proposed alum regeneration system in a bench scale model. The
resultant hydroxide sludge was then treated with sulphuric acid
(H2SO/,) to regenerate the alum. The resulting recovered alum was
added to another sample of clarified biological system effluent.
This process was repeated for six cycles. Table k summarizes the
alum recovered for an equal volume basis. The kO to 50img/l of
unrecoverable alum in each cycle was constant, regardless of the
dosage with the range studied.
Other operating information for the alum recovery system (see Figure
12, page 34) at the pilot plant was obtained during the pilot plant
study. The alum sludge was pumped periodically from the alum clari-
fier to a container. It was then poured into settling cones. The
supernatant was siphoned off. Sulphuric acid was added to adjust the
pH to 2.0, thus solubilizing the alum. The solution was then filtered
to remove solids and fed back into the system. Alum loss of approxi-
mately 10% during operation required that the addition of an alum
make-up solution be added to maintain a stable alum concentration.
/
».
Employing a 300 mg/1 alum slurry, clarifier sludge volumes averaged
3.03 liters per day for treatment of 288 liters of waste. This
represents ].0k% of the treated waste volume of 1.38% when extrapolated
for a 400 mg/1 alum slurry treatment. The recovered alum concen-
tration was calculated to be 2.k% based upon a 50 mg/1 alum-in-
22
-------
Table 3- ALUM PRECIPITATION SYSTEM
Alum dosage - 250 mg/1
to
Date
11/2/71
11/3/71 ,
11 A/71
11/5/71
11/9/71
11/10/71
11/11/71
11/12/71
Average
In
4.2
3.9
2.8
0.9
0.4
0
0.2
0.1
Phosphate,
mg/1
Out
0.5
0.6
0.8
0.7
0.1
0.1
0
0
1.6 0.4
In
70
65
70
85
45
120
85
95
79
TOC,
mg/1
Out
45
70
45
40
40
80
55
70
56
In
0.065
0.150
0.140
0.160
0.200
0.215
0.230
0.215
0.172
Color,
FCU
Out
0.025
0.100
0.090
0.115
0.100
0.185
0.190
0.185
0.124
-------
Table 4. ALUM REGENERATION LOSSES - LABORATORY STUDY
Alum dosage - 500 mg/1, Initial color = 0.219 FCU
NJ
JS-
mg/1 alum recovered
% alum recovered
mg/1 alum lost3
effluent color, FCU
Cycle
1
460
92
4o
0.117
Cycle
2
410
89
50
0.088
Cycle
3
380
93
30
0.125
Cycle
4
320
84
60
0.062
Cycle
5
200
63
I20b
0.084
Cycle
6
140
70
60
0.133
Average loss/cycle = 48 mg/l
b Statistically eliminated by Chauvenet's criterion2
-------
sludge effluent loss. Hence, acid requirements for reclaiming the
alum were found to be 50 ml of sulphuric acid (98% H SQ,) per 3.8
liters sludge, or 1.3% by volume.
Average suspended solids analyses of the influent waste and the
alum clarifier effluent showed a 5 mg/1 volatile solids decrease, and
a 7 mg/1 total suspended solids increase. The 12 mg/1 solids
addition was due to hydroxide floe carryover to the effluent, cor-
responding to a k6 mg/1 alum loss in the clarifier. Also, the solu-
bility of aluminum hydroxide in water is 1.04 mg/1, or an equivalent
of 4 mg/1 alum. Thus, the total permanent alum loss for the pilot;
plant operations was approximately 50 mg/1, agreeing well with the
laboratory findings.
Alum regeneration by sulphuric acid addition to alum sludge was
introduced to the pilot plants early in November, 1971. Except for
a 1-1/2 month period starting in January, 1972, alum regeneration
continued until the completion of the project.
pH
Another series of tests were performed to determine the pH effects
on alum precipitation. Table 5 indicates that color reduction is
fairly constant and that alum becomes insoluble from a pH of 5.0
through 7-5. At a pH of 4.5, color reduction decreases and the alum
becomes more soluble. -
RESIN SELECTION
$
Initially, a preliminary program was established to select the most
efficient resins for use in extended studies. During January and
February, 1972, three different adsorbent resins were tested on
a pilot plant scale for their color removal capabilities. The
resin pilot plant was set up to treat the effluent from the biological
clarifier of the catalyzed biological pilot plant.
During the first period, three resins (Fram FR-37, FR-42, and FR"56)
were tested for their relative color removal capabilities. FR-37
is a highly porous resin specifically designed to remove "organics"
from water. FR-42 and FR-56 are macroreticular weakly basic an ion
exchange resins. FR-42 resin was tested throughout this period for
use as a comparison to the performances of FR-37 and FR-56. Wide
fluctuations in the resin performances were attributed to the un-
stability in the biological pilot plant at that time. Also fluctua-
tions were inherent to the resin treatment process because of its
cyclic nature; color removal decreased as the cycle neared comple-
tion. Regeneration and the start of a new cycle renewed the color
removal efficiency.
25
-------
Table 5. pH CFFECT ON ALUM PRECIPITATION
Alum dosage 1,000 mg/1
PH
7.5
7.0
6.8
6.5
6.0
5.5
5.0
4-5
i
Effluent color3
0.079
0.082
0.081
0.060
0.067
0.068
0.066
0.118
mg/1 alum
In supernatant
10
10
10
10
10
10
10
120
a Influent color * 0.200 FCU
-------
The dally percent color removals for FR-42 resin are shown In Figure
9. Color removals climbed to a peak of over 50% in late January,
but quickly dropped to approximately 20% in early February. This
sudden drop of resin efficiency corresponds to a dramatic decrease
in color reductions in the biological pilot plant (see Figure 14,
page 38). The percent color remov/als for FR-37 and FR-56 resins
again reflected the instability present in the biological pilot
plant (see Figure 14). Wide fluctuations are evident.
Two resins were compared to the FR-42 resin. During the nine day
testing period for the FR-37 resit), color removals for the FR-37 and
FR-42 were 30 and kk%, respectively. Therefore, FR-37 was con-
sidered less effective. The second resin, FR-56, to be tested with
FR-42 was tested for a 14-day period. Color Removal for the FR-42
was 26% and for the FR-56 * 30%. Therefore, FR-56 resin was selected
for use in future extended pilot studies because of its superior
color removal characteristics.
SEQUENCE OF RESIN TREATMENT
The resin treatment was considered both as a potential alternative
to the alum pilot plant system and as an addition to the biological
and alum treatment systems* Theoretically, it seemed that the resin
system would be most effective following an alum flocculation system.
The biologically and alum treated waste would be relatively free of
suspended solids and thus resin fouling would be avoided. An
additional consideration was that the resin system would experience
smaller color loadings due to the partial color removal afforded
by the alum flocculation system. The pilot plant operations pro-
vided the data for the studies conducted on the resin with biologically
treated effluent. Laboratory tests on resin performance using
biologically and alum treated effluent were conducted.
LABORATORY TEST PROCEDURE
FR-42 resin was selected for use in the laboratory test. A burette
containing 50 ml of resin was used to treat the biologically clarified
effluent after it had been flocculated with 400 mg/1 alum, the waste
was passed through the resin column at a flow rate that allowed a
fifteen minute detention time. Twenty thousand ml of alum treated
waste with approximately 0.10 FCU were fed through the burette
before the color removal decreased to 50%. The resin demonstrated
excellent color reductions as shown by its breakthrough curve in
Figure 10.
The performance Of FR-56 resin with biologically treated waste Was
compared to the FR-42 resin with alum treated, biologically treated
effluent. Both types of resin were virgin resins at the beginning
of the test periods. During the six-day period, FR-56 resin was
27
-------
Figure 9
Resin pilot plant performance
O
_J
O
O
LU
O
Of.
50
40
30
20
10
RESIN TYPE:
FR 42
FR 37
FR 56
15
30
15
JANUARY
FEBRUARY
-------
Figure 10
Resin treatment of alum clarifier effluent
0.10
ALUM CLARIFIER EFFLUENT
vo
o
o
0.08
0.06
0.04
0.02
RESIN EFFLUENT
1
I
50
100 150 200 250 300
WASTE TREATED, liters/liter resin
350
400
-------
used for treating a biologically treated waste with the resultant
average of 0.084 FCU (see Figure 9, page 28 ). The laboratory
study of FR-42 resin utilized an alum treated waste with approxi-
mately the same amount of color - 0.101 FCU. The test results
indicate similar performance.
FR-56 resin treated a total of 575 ml of waste per ml of resin
before the percent color removal decreased to 50% (see Figure 9»
page 28). FR-42 resin was capable of treating kOQ ml of waste
per ml of resin yielding an equivalent color removal of 50%. The
treated volume of waste was expected to be lower for the FR-42
resin because of the slightly higher influent waste color; also,
the pilot plant results of January and February, 1972, predicted a
slightly lower color capacity for the FR-42 resin.
It may be concluded that resin treatment is equally effective both
before and after alum flocculation of biological clarifier waste.
30
-------
SECTION V
DESCRIPTION AND OPERATION OF PILOT PLANT
The pilot plant system was designed as a carbon catalyzed biological
system for secondary treatment. For tertiary treatment, an on-site
alum pilot plant system was evaluated. An alternative method to upgrade
the waste effluent from the biological pilot plant with the use of
resin adsorption columns was also investigated.
TREATMENT SYSTEM - BIOLOGICAL
The biological pilot plant employed at Cone Mills was a completely
mixed, activated sludge system as depicted in Figure 11. Untreated
waste from Cone Mills was continuously collected in a small holding
tank used to provide equalization and storage for the feed pump. The
waste feed pump was a peristaltic type with a variable speed drive
and was used to provide flow to the catalyzed aeration system at
150 - 200 mi 11iliters per minute. The aeration system consisted of
three catalyzed biological reactors operating in series.
Each of the three aeration vessels had a volume of 125 liters, yield-
ing a detention time of 10.4 - 13.9 hours in each stage, depending
on the flow rate. To catalyze the biological reaction, 625 grams of
carbon were initially placed in each aeration vessel. Aeration was
provided to each reactor via a rotameter for air flow control and
a set of three fixed porous stone diffusers located in the bottom
of each aeration vessel.
In order to maintain the high concentration of biological solids
necessary for biodegradation, a settling tank was provided following
the third stage aeration tank. Effluent from the third stage aeration
tank was discharged to the cone shaped biological clarifier (settling
tank) where the suspended solids consisting primarily of micro-
organisms were allowed to settle. To insure these solids did not
adhere to the walls of this clarifier, an automatic scraping device
was provided. The clarified supernatant was passed on to the alum
or resin system for further treatment. The suspended solids collected
at the bottom of the clarifier were returned to the first aeration
tank to maintain the desired micro-organism concentration in the
system. To control the return sludge rate, an off-time clock was used
to actuate a small centrifugal pump (see Figure 11) at intervals of
15 minutes. Periodically, biological sludge was wasted from the
clarifier when blomass concentrations became too high, and after
stable operating conditions were obtained, the unit was operated on
a continuous 100% recycle.
31
-------
MIXERS
INFLUENT PUMP
SETTLER
SCRAPER
-* EFFLUENT
SETTLER
RECYCLE PUMP & TIMER
Figure 11
Biological pilot plant
-------
TREATMENT SYSTEM - ALUM
A schematic diagram of the pilot plant is shown in Figure 12. Bio-
logically treated waste from the biological clarifier was mixed with
alum and sulphuric acid in the flocculator with a 100-minute de-
tention period. The sulphuric acid was used when required for
pH control in the flocculator. The clarified biological effluent
now containing aluminum hydroxide sludge at a pH of 6.5 - 7.5 (as
adjusted) was then sent to a second clarifier with a 4.9 hour de-
tention period to produce a clear effluent. Pilot plant operations
were continuous through the second clarifier. The batch alum re-
covery operations as described below were conducted manually.
i.
The hydroxide sludge containing influent suspended solids and pre-
cipitated phosphates was drawn off daily from the bottom of the
clarifier and collected in a receiving tank. The sludge was acidified
with concentrated sulphuric acid to dissolve the aluminum hydroxide
and recover it as aluminum sulphate. The recovered alum solution
was added to the alum feed tank for reuse in the flocculator.
Daily analyses of COD, BODr, volatile and total suspended solids,
ammonium and phosphate content, color and pH were made of the
flocculator influent waste and the clarifier treated effluent.
TREATMENT SYSTEM - RESIN
During the months of June and July, 1972, FR-56 resin was further
tested in a pilot plant confirmation study using biological clarifier
effluent from the existing Cone biological treatment system. This
waste was similar to that from the biological pilot plant.
The resin pilot plant consisted of a glass column 76.2 centimeters
high and 2.5 centimeters in diameter, and a feed pump (see Figure 13).
A total of 300 ml of resin was utilized in this column. The
treated clarifier effluent was pumped downward through the resin bed
at a rate of 20 ml per minute. This rate afforded a 15-minute
detention time. The column was run 2k hours a day for 7 to 10 days.
After this time period, the resin became loaded with contaminant
and could not operate at its maximum efficiency. The resin loading
was reflected in the simultaneous deterioration of the effluent
quality. At this point, the resin was regenerated in the column in
a downflow direction.
Several steps were necessary for regeneration (see Figure 13)« The
first step was to remove solids particles that accumulated on
the resin bed during the treatment of clarifier effluent. This
was accomplished by backflushing the resin with six liters of water
at 200 ml per minute upflow. After backflushing, the adsorbed
color was stripped from the resin using five liters of 2% caustic
33
-------
H2S04
FRAM BIOLOGICAL
CLARIFIER EFFLUENT
ALUM
FEED
£
ALUM
5
RECOVERED
ALUM ~
I FILTRATION U-,
I i I
L ! I
i
I
I
TREATED
r
T~ ~1 ^^MMED.
IsETTLIMsT SOLIDS
1
Figure 12
Alum pilot plant
-------
vn
BIOLOGICALLY TREATED
EFFLUENT
SPENT
^^BMB» ^^H» » oi^H* ^MB
11
1
1
,1
« *
CAUSTIC WATER ACID
1 II
1 1 1
J - i J
i
RESIN
ADSORPTION
COLUMN
TREATED
REGENERATE
EFFLUENT
Figure 13
Resin pilot plant
-------
at a temperature of 130 - 140° F. This was pumped downward at a
rate of 100 ml per minute. The caustic was followed by a two liter
warm water rinse to remove excess caustic on the resin. The residual
caustic was then neutralized with four liters of 2% sulphuric acid
and given a final rinse with two liters of water.
36
-------
SECTION VI
PILOT PLANT DATA
Pilot plant operations at Cone Mills can be categorized into three
phases. Those phases are described by the following time periods:
Phase I - September 23, 1971 to November 12, 1971
Phase II - November 13, 1971 to March 22, 1972
Phase III - March 23, 1972 to May 25, 1972
In general, biological pilot plant performance was found to be good
for Phase I and Phase III; however, many operating difficulties
were encountered during Phase II which adversely affected pilot
plant performance.
One of the goals of the pilot plant study was to obtain maximum
system and process efficiency. Average percent removals of BODg,
COD, and color for the three phases are shown in Figure 14. The
drastic decrease in removals during Phase II is attributed to biolog-
ical fouling of aerators in the reactors, causing plugging and
oxygen deficiencies. With the installation of new aerators prior to
Phase Ml, immediate gains in process performance were realized.
Sludge wasting was considered to be an influencing factor in both
system and process efficiency.
Table. 6 was compiled from data from the last part of Phase III and
reflects the optimum system and process performance that were
achieved by the biological pilot plant alone.
PHASE I
Fram personnel initiated Phase I of the program by the installation
of the pilot plant at Cone Mills on September 23, 1971. Data were
collected throughout Phase I. A comparative analysis of Cone Mills1
waste effluent and the biological pilot plant waste indicated improve-
ment in BODjj removal (Table 7)
Phase I was characterized by new aerators, no sludge wasting and a
detention time of 42 hours in the three reactors. The first reactor (Rl)
removed the bulk of BODc and color as expected in a staged aeration
system. The second and third reactor (R2 and R3) increased the total
color removal from the Rl effluent by approximately 50%, while the
increase for the BOD removal was approximately 11*. Total BODj
37
-------
Figure 14
Biological pilot plant overall performance
o
Z3
a
100
90
80
70
60
50
40 i
BODs
COD
COLOR
I I I I I I I J
L 1 I I
o
o
o
LU
O
CQ
01
a.
-------
Table 6. BIOLOGICAL PILOT PLANT - OPT IHUM PERFORMANCE
Data for phase IK, period 3
VO
Parameter
COD, mg/1
BODg, mg/1
SS, mg/1
Nitrogen as ammonia,
mg/1
Phosphate, mg/1
Color, FCU
pH
Median
135
4.5
27
2.0
1.7
0.130
7.6
35% Percent ile
185
6.2
54
5.2
4.0
0.161
8.15
Average
remova 1 , %
91
99'
-
76
-
90
-
-------
Table 7. COMPARISON OF PILOT PLANT AND MAIN PLANT EFFLUENTS
Phase 1
Parameter
Cone effluent
Fram effluent
, mg/1
SS, mg/1
Phosphate, mg/1
Color, FCU
39.0
56.0
1.5
0.279
35
1.5
0.198
-------
and color removals for the three reactors were 98. ]% and 76.5%, re-
spectively (Table 8). Additional color and BODc removal were achieved
in the biological and alum clarifiers as described later in this
report.
Although the low dissolved oxygen concentration in the first reactor
did not inhibit growth of the micro-organisms, it did limit the
amount of bi ©degradation that occurred. With the installation of
new aerators prior to Phase II, the dissolved oxygen (D.O.) concen-
tration was maintained at a higher level and, as a result, a better
BODc; removal was obtained.
PHASE 1 1
The system was operated under conditions identical to those of
Phase I .
In mid-December, 1971, a sudden increase in color and BODc in the
effluent from the biological system was noted. Analytical tests
determined that a shock loading of metallic ions had been received;
chromium and zinc seemed to have killed the micro-organisms. The
existing waste treatment plant did not seem to be affected in the
same manner. Because of this upset, the entire pilot plant was flushed
and restarted in early January, 1972. The unit was operated as
before except that sludge was wasted occasionally.
, COD, and color reductions immediately following start-up were
satisfactory; however, they rapidly began to decrease after two
weeks of operation (see Figure 14, page 38). By late February, 1972,
BOD5 reductions had dropped to 75%, while color reductions had dropped
to 30%. COD removal was as low as 55%' The D.O. levels in the system
were also noted to be lower than during Phase I. To determine
if contaminated carbon was the source of trouble, additional carbon
was added to the reactors. No improvement in treatment was noted
following addition of the carbon.
It was decided to shut the system down, completely clean out the
pilot plant, and replace the aerators and carbon. Inspection of
the old aerators showed them to be partially plugged. The used
carbon was found to be neither fouled by sludge nor by heavy
metals.
The system was restarted for Phase III.
PHASE III
Phase III operations were begun the end of March, 1972, after com-
pletely cleaning the pilot plant and replacing the aerators and carbon.
1*1
-------
Table 8. BIOLOGICAL PILOT PLANT DATA - PHASE I
Average values
Parameter
BOD5, mg/1
D.O., mg/l
Color, FCU
Nitrogen,
mg/1
Phosphate,
mg/1
Influent
443
2.1
0.932
11.89
2.1
Reactors
1 2 3
60
0.6
0.465
-
-
21
1.3
*
0.283
-
-
8.5
3.2
0.219
-
-
Biological
Clarlfier effluent
-
-
0.198
2.82
1.5
-------
The sudden increase In BODr, COD, and color removals was dramatic,
reaching levels experienced during Phase I (see Figure H, page38 ).
Because of changing operating conditions experienced during Phase III,
it may be subdivided into three periods. The periods are charac-
terized by the following parameters:
Period 1 A total retention time of 31 hours in the reactors
Period 2 Clean aerators identical in number and size to
those of Phase I
Period 3 Periodic sludge wasting
The second period is identical to Period 1 except that three aerators
were added to the first reactor to increase the D.O. level. The
third period is identical to Period 2 except that sludge was wasted
on a regular basis. Each period's operating conditions represent
an improvement over the previous period, in regards to removal
efficiencies (see Table 9).
Period I of Phase III compared to Phase I shows improvements
in BODt; and color reductions (Table 9) Clean identical equipment
was used for both time intervals. The variables were total detention
time and periodic sludge wasting. Since the lower detention time would
affect a system negatively, it was assumed that the periodic sludge
wasting was responsible for the increase in BODr and color removal.
The first reactor (Rl) showed marked improvement in BODjj and color
reductions (k.3% and 7-5%, respectively). While the total BOD5
removal did not increase significantly, total color removal in-
creased by k.B%. The D.O. levels were similar for these two evalua-
tion periods.
The low D.O. concentration in Rl was thought to prevent complete
biological degradation. In Period 2, three aerators were added to
the first reactor (Rl). With the additional aerators, the D.O.
level in Rl nearly doubled (Table 9, page 44 ). Color removal in Rl
jumped from 57.53 (Period 1) to 80.0% (Period 2), resulting in a
total color removal increase of 3-8% from the three reactors. BODj
removals in Rl increased 5-7% in Period 2. Because no additional
air source was added, it was concluded that the original air diffusers
had become ineffective. Upon inspection at a later date, the air
diffusers were found to be fouled with biological growth.
Up until late March, sludge wasting was performed on a limited basis
only. The advantages of. periodic sludge wasting were seen in Period
1. The benefits of regular sludge wasting were realized in Period 3-
-------
Table 9- PERFORMANCE OF BIOLOGICAL REACTORS
Parameter
BOD
% removed
Reactor Rl
Reactor R2
Reactor R3
Total
Color,
% removed
SI
Reactor Rl
Reactor R2
Reactor R3
Total
D.O. , mg/1
Influent
Reactor Rl
Reactor R2
Reactor R3
COD
% removed
Total
Phase 1
86.5
8.8
2.8
98.1
50.0
19.6
6.9
76.5
2.1
0.6
1.3
3.2
-
Phase 1 1 1
Period 1 Period 2 Period 3
90.8
6.0
1.5
98.3
57.5
15.0
8.8
81.3
2.0
0.6
2.2
3-3
84.5
96.5
1.8
0.5
98.8
80.0
2.3
2.8
85.1
3.0
1.1
3.3
3.8
89.6
96.8
2.1
0.3
99.2
86.5
3.2
0.9
90.6
2.2
1.0
2.4
3.6
95.4
-------
During Period 3, the pilot plant was operated under conditions
identical to those of Period 2, except that sludge was wasted on a
regular basis. The improvements in BOD^ reduction were slight, in-
creasing BODjj removal by 0.3$. As shown before, in comparing the
benefits of sludge wasting in Phase I (no sludge wasting) and Period 1
(periodic sludge wasting), color removal was the most sensitive para-
meter to the amount of sludge wasted. The color removal for Period 3
increased 6.5% in Rl, giving a total overall color removal increase
of 5.5% over Period 2.
The operating conditions imposed during Period 3 are considered to
be an optimum level. Period 3 .most closely simulated the design
parameters of an actual plant, including sufficient aeration and
regular wasting of activated sludge. Figures 15 through 21 graphically
illustrate the percent occurrences of concentration values for
the raw, untreated waste and the biological clarifier effluent.
ALUM PILOT PLANT RESULTS
The biological pilot plant effluent was further treated in the alum
pilot plant system. This additional system was recommended to
increase the removal of the phosphates and reduce the color content
in the Cone effluent.
»
The actual performance of the alum pilot plant over a period of
three months (March 23 to May 25, 1972) was close to that predicted
in the preliminary laboratory studies. Table 10 summarizes the
average influent and effluent characteristics during this period
using alum concentrations of 300 mg/1. Reductions in BODj and COD
were approximately 38% and \3%, respectively. Phosphate content
of the waste was reduced consistently to 0.1 and 0.2 mg/1 levels,
regardless of the influent concentration (varying from 0.2 to 6.4 mg/1).
The low final concentration was expected since the precipitated
aluminum phosphate has a constant low solubility.
i
Color removal was found to be more variable and complex. Analysis
of the clarifier effluent color with respect to the clarifier pH
indicates a slight dependence of color removal on pH. Referring to
Figures 22 and 23, fluctuations in influent and effluent color versus
the final effluent pH were apparent. These fluctuations appeared
to fall within certain limits. In order to normalize these variations,
approximate limits were established and the limit averages taken to
yield average color values at various clarifier pH's. Average per-
cent color removal versus clarifier pH is shown in Table 11. Average
color removals varied from 30% to 4U for clarifier pH's of 7.25
and 6.25, respectively, yielding a pale yellow effluent. Treat-
ment schemes employing lower clarifier pH's for added color removal
were considered uneconomical because of the large acid requirements
(see titration curve, Figure 24).
45
-------
a
o
o
1900
1800
1700
1600
1500
1400
1300
1200
1100
BIOLOGICALLY TREATED
EFFLUENT
UNTREATED WASTE
Ml
Figure 15
COO content
(optimum performance)
i t I I I I II II
0.01
} 5 10 30 50 80 95 99
PERCENTAGE OCCURRENCE EQUAL TO OR LESS THAN STATED MAGNITUDE
i 200
150
100
50
99.9
o
o
-------
o>
lf\
O
O
m
800
700
600
500
400
300
200
1001
0
.01
Figure 16
BOD content
(optimum performance)
UNTREATED WASTE
BIOLOGICALLY
TREATED WASTE
i I II I I I I I I I I I I f
1 5 10 30 50 80 95
PERCENT OCCURRENCE EQUAL TO OR LESS THAN STATED MAGNITUDE
99
8
3
2
99.9
o>
IA
Q
O
CO
-------
2.60_
Figure 17
Color content
(optimum performance)
2.20
CO
ID
o
on
o
o
o
1.80
1.40
1.00
0.01
I i I
UNTREATED WASTE
BIOLOGICALLY TREATED
WASTE
Mill! I
1 5 10 30 50 80 95 99
PERCENTAGE OCCURRENCE EQUAL TO OR LESS THAN STATED MAGNITUDE
0.20
0.18
0.16
0.14
0.12
DC
O
_J
O
o
0.10
99.9
-------
70
Figure 18
Suspended solids content
(optimum performance)
VX>
o>
CO
o
o
to
o
LU
O
Q_
CO
co
60
50
40
30
20
10
0
BIOLOGICALLY TREATED
EFFLUENT
UNTREATED
WASTE
1 5 10 30 50 80 95 99
PERCENTAGE OCCURRENCE EQUAL TO OR LESS THAN STATED MAGNITUDE
200
175
150
CO
o
to
o
LU
o
a.
CO
ID
CO
-------
16.0
14.0
Figure 19
NH4 content
(optimum performance)
12.0
o>
10.0
8.0
UNTREATED WASTE
6.0
4.0
2.0
0
0.01
BIOLOGICALLY TREATED
EFFLUENT
II II I I I I I I I II I I
1 5 10 30 50 80 95 99
PERCENTAGE OCCURRENCE EQUAL TO OR LESS THAN STATED MAGNITUDE
99.9
-------
8J
Figure 20
Phosphate content
(optimum performance)
6.1
*- S.i
«
O.
O
4.1
3.1
2J
1.1
0
0.01
BIOLOGICALLY TREATED EFFLUENT
til I
I III I
1 5 10 30 50 80 95 99
PERCENTAGE OCCURRENCE EQUAL TO OR LESS THAN STATED MAGNITUDE
99.9
-------
Figure 21
vr
ro
Q.
8.4
8.2
8.0
7.8
7.6
7.4
7.2
7.0
0.01
PH
(optimum performance)
BIOLOGICALLY TREATED
EFFLUENT
UNTREATED
WASTE
II II I I I I I I I II II
1 5 10 30 50 80 95 99.
PERCENTAGE OCCURRENCE EQUAL TO OR LESS THAN STATED MAGNITUDE
11.5
11.0
10.5
10.0
9.5
99.9
-------
Table 10. AVERAGE PERFORMANCE OF ALUM PILOT PLANT
Alum dosage - 300 mg/1
Vfl
Parameter
BODg, mg/1
COD, mg/1
Volatile suspended
solids, mg/1
SS, mg/1
Nitrogen, mg/1
Orthophosphate,
mg/1
Color, FCU
pH
Influent
10
161
31
32
5.3
0.2 - 6.4
0.208
5.0 - 7-8
Effluent
6.2
130
26
39
5.5
0.1 - 0.2
pH dependent
As adjusted
Percent
reduction
38
19
16
0
Up to 97
-------
Figure 22
0.40 r-
Alum clarifier influent color versus
clarifier pH
data taken 3/24/72 thru 5/25/72
0.35
o
U_
cc
o
0.30
0.25
0.20
0.15
0.10
0.05
KEY: APPROXIMATE LIMITS
LIMIT AVERAGE
5.0
5.5
6.0
J_
6.5
PH
7.0
7.5
8.0
-------
0.40
Figure 23
Alum clarifler effluent color versus
clarifier pH
(300 ppm alum)
data taken 3/24/72 thru 5/25/72
0.35
a:
o
0.30
0.25
0.20
0.15
0.10
0.05
5.0
KEY:
5.5
APPROXIMATE LIMITS
LIMIT AVERAGE
i
6.0
I
6.5
PH
7.0
7.5
8.0
55
-------
Table 11. COLOR REMOVAL AT VARIOUS CLARIFIER EFFLUENT pH'S
Pilot plant
Ul
Clarifier pH
6.25
6.50
6.75
7.00
7.25
Observed color removal, %
k]
40
39
35
30
-------
1.92
Figure 24
Titration curves of lagoon waste
1.68
3 1.44
o>
E 1.20
n>
0»
o
0.96
£ 0.72
a-
UJ
QC
CM
0.48
0.24
WASTE WITH 300 mg/1
ALUM
4
RAW WASTE
8
pH
57
-------
An increase tn the total suspended solids content was observed
across the clarifier (refer to Table 10, page 53 ). The increase
of 12 mg/1 was caused by a carryover of aluminum hydroxide floe
to the effluent (corresponding to a 46 mg/1 alum loss). Although
pilot plant operations did not include the use of polyelectrolytes,
laboratory tests have indicated that 5 mg/1 of a cationic poly-
electrolyte markedly decreases the settling time and solids overflow.
No reductions in ammonia were observed for the alum coagulation
system, as expected, due to the solubility of the ammonium com-
pounds formed. The average concentration before alum treatment
was 4.12 mg/1 and after alum treatment 4.11 mg/1.
ADDITIONAL COLOR REMOVAL SCHEMES
Several other color removal schemes were considered to supplement
the alum pilot plant system. Carbon treatment of the flocculated
waste was investigated in preliminary laboratory shaker tests.
Powdered Activated Carbon
Powdered activated carbon added to the 400 mg/1 alum plus waste
mixture was observed to completely remove the waste color after-an
extended time period (less than four hours). However, only partial
removal was evident using up to one hour detention and a 50 mg/1
powdered carbon concentration (see Figure 25). Color removal due
to 50 mg/1 carbon addition quickly reached a maximum of approxi-
mately 32% after 10 minutes reaction time and then desorbed color
until no color removal was evident after one hour. Even at the
32% removal level, the treated waste still had a distinct yellow
color. I
Chlorination
Chlorination was found to reduce color in the alum treated waste sig-
nificantly at high chlorine levels (see Figure 26). Laboratory
tests showed a 63% color removal for chlorine levels of 48 mg/1 with
a contact period of 5 minutes. The waste was observed to be a
pale yellow at the 63% removal level.
Adsorptive Resins
Adsorptive resins also demonstrated color removal characteristics
for Cone Mills' full scale biological clarifier effluent. Studies
that were performed by Cone Mills are discussed in detail on page 63.
58
-------
Figure 25
Carbon adsorption of color
during alum flocculation
(50 mg/1 carbon)
O£.
O
_1
O
o
o
o:
INITIAL COLOR 0.12 FCU
20
10
10 20 30 40
ADSORPTION TIME, minutes
60
59
-------
Figure 26
80
Effect of chlorination on color
removal for alum treated clarifier waste
(400 mg/1 alum)
70
60
50
-------
RESIN PERFORMANCE
A resin pilot plant study was performed in June and July, 1972 to
evaluate the performance of FR-56 resin (selected in the previous
study). During this period, the Cone Mills' biological treatment
system performance was stable, affording an excellent source of
biological clarifier effluent which resembled the typical effluent
from the biological pilot plant.
Referring to Figure 27, the biological clarifier effluent color
averaged 0.089 FCU; the resin effluent varied between 0.001 and
0.059 FCU, depending on the volume of waste treated since resin
regeneration. The cyclic nature of the process is evident from
the resin effluent color variation. The percent color removals for
the test period are shown in Figure 28. The average percent color removal
for the entire period was 81%. A summary of the average resin
effluent quality and percent reductions for all the parameters
monitored during the study are given in Table 12. The resin has
the capability to treat between 670 and 960 liters of waste per liter
of resin before regeneration is necessary.
The results of this pilot plant confirm that resin treatment of the
biological clarifier effluent is an effective method for trace color
remova1.
HEAVY METALS
The concentration of heavy metals in the biological sludge was
observed during this study. Regular wasting of sludge was found to
drastically reduce the heavy metal concentrations in the sludge,
yielding copper, chromium, and zinc concentrations of 1 to 5 mg/1.
Periodic sludge wasting yielded higher concentrations ranging from
25 to 70 mg/1 (see Table 13). Feed concentrations were generally
from 0 to 2 mg/1. Since high metal concentrations may impede
normal biological growth, continual sludge wasting is most desirable.
61
-------
Figure 27
Resin treatment of clarifier effluent
(FR-56 resin)
ID
O
O
O
0.14
0.12
0.10
0.08
0.06
0.04
0.02
CLARIFIER EFFLUENT
20 25 30
JUNE
10 15
JULY
20
62.
-------
Figure 28
Pilot plant performance
(FR-56 resin)
O
LU
Q£
0£
O
_l
O
LU
O
OL
LU
Q.
100
80
60
40
20
20 25 30
JUNE
10
15
20
JULY
-------
Table 12. RESIN PERFORMANCE SUMMARY
FR-56 Resin
Parameter
Color, FCU
BODj, mg/1
COD, mg/1
TOC, mg/1
Total phosphate,
mg/1
Nitrogen (Nh^) ,
mg/1
SS, mg/1
pH
Average
effluent quality
0.022
1.6
128
23
2.0
2.3
3.6
8.1
Average
percent reduction
81
I H
25
j
26
*»9
i 0
j
56 v
No "change
-------
Table 13. HEAVY METAL CONCENTRATIONS IN RETURN BIOLOGICAL SLUDGE
er\
Ul
Metal
Copper3, rag/1
Chromiumb, mg/1
Zinc°, mg/1
Periodic wasting
23.8
68.6
23.8
Regular wasting
a Typical copper influent concentration - 0.15 mg/1
b Typical chromium influent concentration - 2.2 mg/1
c Typical zinc influent concentration = 0.45 mg/i
1.0
5.2
3.7
-------
SECTION VI I
KINETIC EVALUATIONS
The biokinetic rate of oxidation of Cone Mills' waste was found to
be dependent on the level of aeration within the reactors. As
reported earlier, an increase in aeration in Reactor 1 resulted
in an increase in BOD,- and color removals. This increase is con-
firmed in Figure 29. The organic removal rate was kj = 0.00217/day
for normal aeration, but increased to kj
aerators.
The relationship of concern here is:
S| - Se
0.0079Vday with additional
k S
e
(2)
Under optimum conditions, the design equation for the first reactor
would be:
- S
e
0.00794 Se
where:
Si -
Se *
Xv -
t
influent BODr concentration, mg/1
effluent BODg concentration, mg/1
mixed liquor volatile suspended solids, mg/1
reactor retention time, days
The observed biokinetic rates for the second and third reactors are
shown in Figures 30 and 31. As expected, these biokinetic rates
are decreasing in order. Reactor 2 has a rate of 0.000689/day,
while the third reactor is 0.000299/day. This is because the organic
contaminants most easily degraded are biologically oxidized first
(in Reactor 1), giving the highest biokinetic rate constant. The
more difficult to degrade contaminants are oxidized later (in Reactor
2 and 3), yielding lower rates.
66
-------
0.20
0.16
> 0.12
0.08
0.04
Figure 29
Biokinetic rate
reactor 1
20
0.00217/day
0.00794/day
NORMAL AERATION
ADDITIONAL AERATION
40
60
80
100
EFFLUENT BOD mg/1
67
-------
0.08
Figure 30
Biokinetlc rate
reactor 2
0.06
X
01
CO
00
r- 0.04
0.02
k2 = 0.000689/day
10
20
30
40
50
60
70
80
EFFLUENT BOD,, mg/1
-------
0.008
Figure 31
Biokinetic rate
reactor 3
0.006
M
X
,* 0.004
I
*T"
co
0.002
k3 = 0.000299/day
10
15
20
EFFLUENT BOD5, mg/1
-------
SECTION VIII
FULL-SCALE MODEL
The laboratory and pilot plant Investigations on Cone Mills' waste
show that successful treatment can be achieved by application of
the processes studied, and further the data obtained during the
study is sufficient to allow the design of a full-scale facility to
treat this or similar types of waste.
The proposed waste treatment plant would consist of three sections:
biological, alum flocculation, and resin adsorption systems. The
biological system would be responsible for removing from the raw
plant waste the bulk of the organics and associated color dyestuffs.
The alum flocculation system would serve to remove nearly all phos-
phates and a significant amount of suspended solids and color from
the biologically treated waste. Any remaining color would be re-
moved by the last system, the resin adsorption system, to render
the plant effluent virtually free of objectionable contamination.
Such effluents could be recycled for further use or discharged 'into
receiving waters pending approval from governmental agencies.
PROCESS DESCRIPTION
A detailed description of a waste treatment plant capable of treating
3,785 cubic meters of waste daily is presented herein. Flow diagrams
in Figures 32a, 32b, and 32c illustrate the proposed process.
BIOLOGICAL SYSTEM - !
t
The biological system is a carbon catalyzed unit process patterned
after the pilot plant. Two activated sludge aeration basins are
utilized to provide maximum efficiency and minimum space requirements.
The first and second basins have capacities of 2,195 and 1,173 cubic
meters, respectively. Each basin contains five kilograms of activated
carbon per cubic meter.
Raw waste enters the first basin where it is combined with return
activated sludge and colored spent regenerate from the resin adsorption
system. After 14 hours aeration, the partially treated waste proceeds
to the second aeration basin where further degradation occurs. After
approximately J.k hours retention period, the biologically treated
waste is clarified in a 155 square meter clarifier. The separated
activated sludge is returned to the first basin, except for a purge
stream which is filtered on a 1.9 square meter vacuum filter.
70
-------
SPENT REGENERATE FROM
RAN
WASTE *~
i
RESIN SYSTEM
i
FIRST AERATION
BASIN
1
SLUDGE
RETURN
LJ
CD
o:
ID
Q.
SECOND Al
"* TION BAJ
IRA-
>IN
HVAlOUM
FILTER
j
LU
1
_J
I i
i TO
iU. .,IU »,
_te pi ADTITTFD T ~~
-* CLARIFIER H AL(JM SYSTEM
-y
MOIST SOLIDS
FOR
Figure 32a
Biological system
-------
«. I
to
BIO-SYSTEM
EFFLUENT
§
.j
«*
1
^h_l
n KLAC
"1 CLAR
^^^
2
i
0
(/>
MAK1
J ALI
ALUM
STORAGE
"* TANK
POLYMERIC
COAGULANT
]-Q|^ U *
IFIER 1 RESIN SYSTEM
ilp*^
SULPHURIC OVERFLOW ^ SLUDGE
IArrn HULU
ACID TANK
^ DI5SOL- »~ AIR
VER FLOTA- ' SOUDS
E_UP g ULILk ~ '^"UlSPUSAL
TT u-
JM g
o
z
_ FILTRATE
Figure 32b
Alum system
-------
ALUM SYSTEM
EFFLUENT
HOLD
BASIN
SAND
FILTERS
JPENTJIEGBJERATE
TO FIRST AERATION BASIN
CAUSTIC/ACID
I
I
I
RESIN
COLUMNS
Figure 32c
Resin adsorption system
-------
The clarifier effluent proceeds to the alum system for further
treatment.
ALUM SYSTEM
The alum system flocculates the biological clarifier effluent by
alum addition and recovers the alum for reuse. The alum recovery
process alleviates the disposal problem associated with the volu-
minous alum sludge in conventional systems.
The biologically treated wastes are flocculated with 300 mg/1 alum
in the center of a 177 square meter reactor-clarif ier for a 10 min-
ute period. From laboratory tests, it was noted that when a polymeric
coagulant is added, there is an increase in the size of the floe
formed. After f locculation, the waste is clarified in the outer-
most portion of the clarifier and sent to the resin adsorption
system for further treatment.
i
The alum floe generated is collected by the clarifier and pumped to
a mixing tank. Here, the sludge is acidified with sulphuric acid to
dissolve the aluminum hydroxide floe. The recovered alum solution
passes on to an air flotation unit where the undissolved solids are
removed. The clarified effluent from the 0.93 square meter flota-
tion unit is received by the alum storage tank for eventual feed to
the reactor-clarif ier. The solids overflow is collected continuously
in the sludge holding tank. The collected overflow is filtered
daily on a 2.8 square meter precoated rotary filter during an 8-hour
period. Approximately 159 kilograms per day of moist solids will
be col lected.
Alum is added to the alum storage tank to replenish alum losses
in the process. The alum concentration in the solution fed to the "
reactor-clarif ier is maintained at approximately 2.5%.
RESIN ADSORPTION SYSTEM
C
The trace amounts of color in the alum system effluent are removed t
by adsorption onto adsorbent resin. The process is cyclic in nature;
regeneration of the resin is required to renew its adsorptive capacity
During this regeneration period, the alum system effluent must be
contained in a hold basin. A 379 cubic meter basin is provided.
The alum effluent is pretreated by four sand filter beds to remove
suspended solids that may foul the resin. Approximately 13 square
meters of filter area are required. The waste then passes to the
resin adsorption columns where virtually all the trace color is
removed from the stream, rendering a plant effluent suitable for
discharge or potential reuse.
-------
The adsorptive resin is housed in three columns piped in parallel
and charged with 18.4 cubic meters of resin. Each column is equipped
with a resin support media and distributors above and below the
resin bed for distribution of waste and regenerate solutions.
Regeneration of the resin column is determined by the effluent
color, or by a timer. During regeneration, the waste flow is
stopped for the duration and allowed to collect in the hold basin.
A warm 2% solution of caustic is passed downward through the
columns, followed by a rinse of warm water. The columns are then
neutralized with a cold 2% solution of sulphuric acid and given a
final water rinse. The regenerate streams contain the color and
organics stripped from the resin. These are recycled to the first
biological aeration basin for eventual degradation. Their total
volume is approximately \% of the volume of waste treated.
PROJECTED EFFLUENT QUALITY
The model waste treatment plant is expected to provide a high level
of treatment which will render the waste suitable for discharge or
reuse.
The projected effluent qualities from the individual treatment
systems are shown in Table 14. Using the average Cone Mills'
waste characteristics, the model plant is expected to provide
virtually complete removal of BOD,- and color (over $8% each),
while COD, suspended solids, and phosphate removals were approxi-
mately 35%. Nitrogen (as ammonia) removal would be lower, approxi-
mately 75%.
ECONOMICS
The model waste treatment plant utilizes several processes that
reduce the capital and operating costs. First of all, the use of
staged aeration and carbon catalysis in the biological system allows
smaller basin sizes than required in conventional treatment. Second-
ly, the use of alum regeneration in the alum system gives savings in
operating expense. Chemical and sludge disposal costs are reduced
significantly.
A summary of the estimated capital expenditure for a 3,785 m3/day model
treatment plant employing the three treatment systems is given in
Table 15. The total capital expenditure is estimated to be $1.49
m i11i on.
OPERATING COSTS
The total chemical, utilities, and labor costs to operate the entire
proposed plant are shown in Table 16.
75
-------
Table 14. PROJECTED EFFLUENT QUALITY
Parameter
BODj, mg/1
COO, mg/1
SS, mg/1
Nitrogen,
mg/1
Phosphate,
mg/1
Color, FCU
pH
Raw
waste
465
1415
157
10.5
1.8
1.217
12-13
Treatment step
Biological Alum Resin
5
127
27
2.5
1.8
0.122
7.5 - 8.0
3.1
103
34
2.5
0.1
0.095
7.5
2.7
77
10
2.5
0.1
0.020
7.5
Overall
percent reduction
99+
95
94
75
95+
98+
-
ON
-------
Table 15. ESTIMATED CAPITAL COST
1972 base
System
Biological system
Activated sludge basins and aerators
(reinforced concrete)
2195 cubic meter capacity
1173 cubic meter capacity
Final clartfier
Vacuum filter
Carbon
Alum system
Reactor-clarlf ier
Flotation equipment
Tanks & feeders
Vacuum filter
Pumps
Resin system
Adsorption columns, 3
Sand filters
Hold basin
Adsorbent resin
TOTAL INSTALLED COST9
Installed cost, $
400,500
221,000
168,000
42,000
23,000
$854,500
173,500
29,300
34,800
48,400
18,500
$304,500
80,000
80,000
29,000
47,500
$236,500
$1.490.000
Including contingencies, land and contractor fees
77
-------
Table 16. ESTIMATED OPERATING COST
1972 Base
CO
Material or Service
Chemicals
Make-up carbon
Make-up alum
Sulphuric acid
Caustic
Mi seellaneous
Utilities
Labor
36 hrs/day § $4.00/hr
TOTAL OPERATING COST
Cost, $
2.0$
1.3*
5.6$
1.6*
1.1*
2.0$
28.0$
a Per 3.79 cubic meters (1000 gallons) treated
-------
Under the existing Federal Income Tax Laws, waste treatment facilities
may be depreciated over a five year period. For purposes of this
example, depreciation and capital recovery will be assumed to occur
over a five-year period with an interest rate of 9%. Table 17 shows
the predicted annual cost for the first five years of operation.
79
-------
Table 17. ANNUAL COSTS
Cost
Annual operating cost
(mVday treated) ($/cubic meter) (days/year)
(3790)(0.28/3.79)(365)
102,200
Annual depreciation
Total installed cost/n
where n - years of depreciation
1, 490,000/5
298,000
Annual interest
(principal) (interest rate)(n + T/n)
(M90,000) (0.09) (6/10)
80,460
TOTAL ANNUAL COST
480,660a
This is equivalent to $1.32 per 3-79 cubic meters (1000 gallons)
treated, and is only valid for the first five years of opera-
tion. After that period, the plant will be fully depreciated
and the operating cost will drop to $0.28 per 3.79 cubic meters
(1000 gallons) treated.
80
-------
SECTION IX
REFERENCES
1. Eckenfelder, W. W. Water Quality Engineering for Practicing
Engineers. New York, Barnes and Noble, Inc., 1970. p. 160 - 163.
2. Hoi man, J. P. Experimental Methods for Engineers. New York,
McGraw-Hill Book Company, 1966. p. 53.
81
-------
SECTION X
GLOSSARY
BODg - Abbreviation for Biochemical Oxygen Demand, five day. The
amount of dissolved oxygen consumed in five days by biological pro-
cesses breaking down organic matter in an effluent.
COD - Abbreviation for Chemical Oxygen' Demand. A measure of the
amount of oxygen required to oxidize organic and oxidizable inorganic
compounds in water.
Darco - Trademark for activated carbon derived from lignite and sold
by ICI America, inc., Wilmington, Delaware.
D. 0.- Abbreviation for Dissolved Oxygen. The oxygen dissolved
in water or sewage.
FCU - Abbreviation for Fram Color Unit. It is measured by using a
variable grating spectrophotometer, where the light absorbance is
measured at three wavelengths - 350, 450, and 550 millimicrons. If
the light absorbance is greater than the instrument scale, the sample
is diluted and a dilution multiplier is used to calculate the ab-
sorbance. The Fram Color Unit (FCU) is the sum of the corrected
light absorbance at these three wavelengths.
FR-37 ~ Designation for synthetic resinous adsorbent sold by Fram
Corporation, Providence, Rhode Island.
FR-42 - Designation for synthetic macroreticular, weak base anion
exchange resin sold by Fram Corporation, Providence, Rhode Island.
FR-56 - Designation for synthetic, macroreticular, weak base, anion
exchange resin sold by Fram Corporation, Providence, Rhode Island.
mg/1 - Abbreviation for milligram per liter.
ml - Abbreviation for mil 151iter.
m^/day - Abbreviation for cubic meters per day.
Nor it II - Trademark for activated carbon derived from peat and sold
by American Nor it Co., Inc., Jacksonville, Florida.
Nuchar WV-G - Trademark for activated carbon derived from bituminous
coal and sold by Westvaco, Covington, Virginia.
82
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ppm - Abbreviation for parts per million. On an equal weight basis,
this term can be used as an equivalent for mg/1.
TOC - Abbreviation for Total Organic Carbon. A measure of the amount
of carbon in a water sample attributable to organic matter.
TOD - Abbreviation for Total Oxygen Demand. The amount of oxygen that
would be consumed if a chemical were to be oxidized to the highest
oxidation state of each element in the compound.
83
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SELECTED WATER
RESOURCES ABSTRACTS
.INPUT TRANSACTION FORM
i, Report If t»
1,*.
3. Accession No.
w
4. Title
CATALYZED BIO-OXIDATION AND TERTIARY TREATMENT OF
INTEGRATED TEXTILE WASTEWATERS
7. Author(s)-
SNYDER, A.J., ALSPAUGH, T.A.
S* Report Bats
8. Pertorittittg Organization
Report No.
10. Project No.
9. Organization
FRAM CORPORATION
« Under Contract to
CONE MILLS CORPORATION
11. Contract I Grant No.
Type pif Report 4gd
* Period Covered
15. Supplementary Notes
Environmental Protection. Agency report number, EPA-660/2-7^-039»
June 1971*
.16. Abstract
This report describes the observations from preliminary studies and pilot
plant operations that were initiated to upgrade the waste effluent of an
integrated textile dye mill. The biological pilot plant was designed to
utilize activated carbon on the basis that the presence of carbon en-
hances bio-degradation.
To meet the proposed water standards, tertiary treatment of the effluent
was also necessary. Two methods of attaining better water effluent were
investigated. A conventional method, the addition of an alum system, with
alum recovery was added to the biological treatment system. Although the
effluent quality improved, trace color remained in the supernatant. An
adsorbent resin system was tested and found effective in upgrading^ the
waste effluent to recreational standards.
The results of preliminary studies and the pilot plant indicate that
carbon catalysis enhances biological degradation, and satisfactory
tertiary treatment can be achieved with an alum and resin system.
17a. Descriptors
*Water Pollution, *Pollution Abatement, *Textile Wastewater treatment,
Wastewater Re-use, Upgrading Biological treatment.
17b. Identifiers
*
Catalyzed Bio-oxidation, *Alum Recovery, Adsorbent Resins, Color Removal,
Activated Carbon.
17c. COWRR Field & Group Q5D
18. Availability
'^^KtfBf
20. Security Ctiss.
P-rice
Send To:
WATER RESOURCES SCIENTIFIC INFORMATION CENTER
U.S. DEPARTMENT OF THE INTERIOR
WASHINGTON. D. C. 2O24O
Abstractor ALVIN J. SNYDER
I initiation FRAM CORPORATION
WRSIC 102 (REV. JUNE 1371)
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