EPA-600/2-78-079
April 1978
Environmental Protection Technology Series
PHYSICAL/CHEMICAL TREATMENT
OF TEXTILE FINISHING WASTEWATER
FOR PROCESS REUSE
Industrial Environmental Research Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
Research Triangle Park, North Carolina 27711
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RESEARCH REPORTING SERIES
Research reports of the Off ice of Research and Development, U.S. Environmental Protec-
tion Agency, have been grouped into nine series. These nine broad categories were
established to facilitate further development and application of environmental tech-
nology. Elimination of traditional grouping was consciously planned to foster technology
transfer and a maximum interface in releted 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 TECHNOLOGY
series. This series describes research performed to develop and demonstrate instrumen-
tation, equipment, and methodology to repair or prevent environmental degradation from
point and non-point sources of pollution. This work provides the new or improved tech-
nology required for the control and treatment of pollution sources to meet environmental
quality standards.
REVIEW NOTICE
This report has been reviewed by the U.S. Environmental
Protection Agency, and approved for publication. Approval
does not signify that the contents necessarily reflect the
views and policy of the Agency, nor does mention of trade
names or commercial products constitute endorsement or
recommendation for use.
Na"onal ™hnical
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EPA-600/2-78-079
April 1978
PHYSICAL/CHEMICAL TREATMENT
OF TEXTILE FINISHING WASTEWATER
FOR PROCESS REUSE
by
J.M. Eaddy, Jr. and J.W. Vann
J.P. Stevens and Company
P.O. Box 21247
Greensboro, North Carolina 27420
Grant S801211
ROAP 21AEC-02
Program Element No. 1B2036
EPA Project Officer: Max Samfield
Industrial Environmental Research Laboratory
Office of Energy, Minerals, and Industry
Research Triangle Park, NC 27711
Prepared for
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Research and Development
Washington, DC 20460
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ABSTRACT
The effectiveness of multimedia filtration has been demonstrated as a
reliable means of tertiary treatment of biologically treated wastewaters from
two adjacent plants involved in dyeing and finishing fabrics of man-made
fibers. Chemical additions of alum, polyelectrolytes, and powdered activated
carbon to the waste stream ahead of multimedia filters effected additional
pollutant and color removals which were required to produce an effluent qual-
ity satisfactory to meet National Pollutant Discharge Elimination System re-
quirements.
A pilot wastewater treatment plant, comprised of a 10 gpm coagulation/
settling/filtration unit followed by a 1.5 gpm 5-column train comprised of
sand filter, organic scavenging resin, granular active carbon, cation ex-
change resin and anion exchange resin was employed to provide an essentially
colorless effluent suitable for dyeing nylon, polyester, acetate and triace-
tate fibers. Tramp color scavenging ability of four fibers in fabric form
was determined. Nylon and triacetate were essentially equal in extremely
high color scavenging ability, while acetate and polyester fibers exhibited
a much lower color scavenging ability.
Relative whiteness determinations showed that an essentially colorless
effluent was needed to consistently dye white and pastel shades on nylon and
triacetate fabrics. Colorfastness of the fabrics dyed with water from the
pilot plant was equal to that of control dyeings.
This report was submitted in fulfillment of Grant Number S801211 by J.P.
Stevens & Company, Inc. under the partial sponsorship of the U. S. Environ-
mental Protection Agency. This report covers an EPA grant period from March
1, 1973 to February 28, 1978. The work was completed as of May 31, 1977.
ii
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CONTENTS
Abstract ii
Fi gures iv
Tab!es v
Abbreviations and Symbols vlli
Acknowledgement x
1. Introduction 1
2. Conclusions .3
3. Recommendations 5
4. J. P. Stevens Manufacturing Facilities 7
5. Wastewater Treatment Plant Operational Considerations 18
6. Multimedia Filtration 21
7. Water Reuse - Pilot Study 65
8. Laboratory Reuse Evaluations 106
9. Preliminary Design of a One Million Gallon Per Day
Treatment Plant 123
ill
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FIGURES
Number Page
1 Biological treatment system 13
2 Receiving stream network in relation to wastewater
treatment plant outfall 15
3 Biological treatment system with multimedia filter 24
4 Multimedia filter, end view 27
5 Chemical addition points 55
6 Effluents Color Comparison, 11/8/76 114
7 Effluents Color Comparison, 9/16/76 H4
8 Process flow schematic - 1 MGD plant 125
iv
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TABLES
Number Page
1 Biological Treatment Plant Engineering Data 10
2 Biological System - Unit Process Description 12
3 Biological Effluent 14
4 Characteristics of Receiving Streams Upstream of Wastewater
Treatment Plant Discharge 16
5 Multimedia Filtration Design Criteria 5 MGD Maximum Flow 22
6 Analysis of Solids 26
7 Pounds Per Day Pollutants Plus Amounts of Color Removed Vta
Multimedia Filtration Without Chemical Addition 30
8 Average Pounds Pollutants and Pt-Co Units of Color Remaining In
Final Effluent After Multimedia Filtration 31
9 Efficiency of Multimedia Filtration - Without Chemical Addition.. 33
10 Raw Waste Response to Alum & To Alum/Polyelectrolyte Dosages 35
11 Raw Waste Response to Alum 36
12 Laboratory Experiments 38
13 Evaluation of Color and Pollutant Removals With 150 mg/1 Alum
At Various pH's 40
14 Laboratory Experiments - Effects of Alum & Powdered Activated
Carbon on Non-Chlorinated, Secondary Clarified, Biologically
Treated Wastewater 42
15 Laboratory Experiments - Effects of Alum & Powdered Activated
Carbon on Non-Chlorinated, Secondary Clarified, Biologically
Treated Wastewater 43
16 Color, Turbidity, COD, TOC, Removed by Powdered Activated Carbon
Addition to Secondary Clarified, Chlorinated Wastewater 44
17 Evaluation of Powdered Activated Carbon Alone as a Color And
Pol 1 utant Removal Chemi cal 46
18 Evaluation of Alum & Alum/Polymer Dosages on Color & Pollutant
Reductions in Biologically-Treated, Secondary-Clarified, Non-
Chlorinated Wastewater 48
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TABLES (continued)
Number Page
19 Evaluation of Alum & Alum/Polymer Dosages on Color & Pollutant
Reductions in Biologically-Treated, Secondary-Clarified, Non-
Chlorinated Wastewater 49
20 Evaluation of Alum & Alum/Polumer Dosages on Color & Pollutant
Reductions in Biologically Treated, Secondary-Clarified, Non-
Chlorinated Wastewater 50
21 NPDES Discharge Requirements, 3-Stage Permit 51
22 Pounds Per Day Pollutants Plus Amounts of Color Removed Via
Multimedia Filtration with Chemical Addition 56
23 Increased Color & Pollutant Removals in Response to Chemical
Additions 57
24 Efficiency of Multimedia Filtration - With Chemical Addition 58
25 Filter Efficiencies As A Function of Different Feed Rates 57
26 Average Pounds Per Day Pollutants Remaining in Final Effluent
After Physical/Chemical Treatment Via Multimedia Filtration
With Chemical Addition Compared to 3-Stage NPDES Permit
Requirements 60
27 Long Term Aeration Effect on TKN in Final Effluent 61
28 Particle Size Distribution 63
29 National Pollutant Discharge Elimination System Discharge
Mon1 tori ng Report 64
30 Design Data for 1.5 GPM 5-Column Pilot Water Treatment Plant 69
31 Evaluation of Color Removal From Textile Wastewater 72
32 pH Evaluation 76
33 Turbi di ty 80
34 Specific Conductivity 83
35 Total Solids (mg/1) 87
36 BOD5 (mg/1) 90
37 COD (mg/1) 92
38 Total Organi c Carbon 94
39 Pollutant Removals Via Pilot Plant 95
40 Ni trogen Seri es 97
41 Phosphorus, Chlorides, Sulfate 100
VI
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TABLES (continued)
Number
42 Metal Series 102
43 Visual Comparison of Color Scavenging By Various Fibers Scoured
In Wastewater 108
44 Instrument Whiteness Comparison, Control Vs. Wastewater Scoured
Fibers in Fabric Form 110
45 Relative Whiteness of Dyed Fibers (Fabric Form) 112
46 Col or Removal -Coagul ation/Settl 1 ng/Fi 1 tration 116
47 Laboratory Dye/Fiber Test Combinations 117
48 Design Data for 1 MGD Scale Up of Pilot Plant 124
vii
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ABBREVIATIONS AND SYMBOLS
ABBREVIATIONS
Avg., Ave.
BOD5
COD
Cu. Ft.
Ft.
FTU
GPSFPD
GPD
GPM, gpm
GPM/sq. ft.
HP
I.D.
JTU
Lbs.
Lbs/Day
MGD
MG/L, mg/1
ml
mm
MPP
N
nm
No.
PAC
PH
--average
--five-day Biochemical Oxygen Demand
--Chemical Oxygen Demand
—Cubic Feet
—Feet
—Formazin Turbidity Units
--Gallons per square foot per day
—Gallons Per Day
—Gallons Per Minute
--Gallons per Minute Per Square Foot
—Horse power
— Inside Diameter
--Jackson Turbidity Units
--Pounds
--Pounds Per Day
—Million Gallons Per Day
--Milligrams per Liter
—Milliliters
--Millimeters
—Mobile Pilot Plant (Coagulation/Settling/Filtration Unit)
--Normality
—nanometers
--number
--Powdered Activated Carbon
—Logarithm (base 10) of the inverse, of the hydrogen ion
concentration. Measure of the acidity or alkalinity of
an aqueous solution.
viii
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ABBREVIATIONS (Continued)
PPM, ppm
Psi
Pt-Co Units
RPM
TOC
ug/1
u.c.
umhos
--Parts per Million
--Pounds per square inch
--Platinum-Cobalt units of color
--Revolutions Per Minute
--Total Organic Carbon
--Micrograms per liter
--Uniformity coefficient
--Micromhos
SYMBOLS
0
°C
°F
-at
--Degrees Celsius
--Degrees Fahrenheit
--Secondary
—Foot (12 inches)
--Inches
--Less than
—More than
—Percent
ix
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ACKNOWLEDGEMENT
The writers gratefully acknowledge the commitment of J. P. Stevens &
Company, Inc. to this project and especially to Mr. Hampton Shuptng, Corporate
Vice President, and Mr. Milton Southerland, Executive Vice President of the
Knit Division, who actively pursued this project; to Mr. W. S. Buckley, and
Mr. G. E. Shelton, General Manager and Manager respectively of the Carter
Plant where this project was carried out, who provided administrative support;
to Mr. W. R. Hogue Director of Corporate Engineering, initial project manager;
to Mr. S. H. Griggs and his staff at the Stevens Environmental Services Lab-
oratory who provided analytical data and technical support; to Mr, A. C.
Talbott, Knit Division Engineer, who supervised erection of the pilot plant
equipment; to Mr. W. D. Setzer who provided accounting support; to Mr. Harry
D. Page, who provided waste treatment operations support; to Mrs. Irene S.
Zibelin who provided clerical support; to the staff of the Carter Plant Lab-
oratory who made dyeing and colorfastness tests for this project.
We also acknowledge Dr. Max Samfield the EPA Project Officer for his
valuable counsel and program planning assistance throughout the project.
We acknowledge John C. Grey & Associates, and particularly Mr. John C.
Grey who did the technical research and prepared the initial project plan.
We acknowledge suppliers of pilot plant equipment; Neptune M1cro-Floc,
Inc. and Hungerford & Terry, Inc. for their valuable technical counselling
throughout the project.
We also wish to acknowledge Engineering-Science, Inc., and in particular
Mr. Thomas N. Sargent, for their preparation of the final draft.
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SECTION 1
INTRODUCTION
The J. P. Stevens and Company, Inc. facilities located in Wallace, N.C.
consist of two manufacturing plants. These plants produce primarily dyed and
finished man-made tricot and doubleknit fabrics. Each of these manufactur-
ing facilities discharge to a common wastewater treatment facility. This
wastewater treatment system, immediately prior to installation of the advanced
wastewater treatment system, consisted of mixing/equalization, extended aeration
activated sludge, clarification and post-chlorination. The biological sludge
wns aerobically digested, thickened, dried on sand beds and disposed of by
land-filling,
A continuing program of stream improvement, including reclassification
and upgrading by the State of North Carolina, and the establishment of the
National Pollutant Discharge Elimination System (NPDES) required a higher
quality effluent and, therefore, more stringent treatment than could be gained
from secondary biological treatment followed by chlorination and post-aeration.
The requirements for the Wallace, N. C. facilities are a maximum (30-day
average) BOD5 and suspended solids concentration of 5 mg/1 for each, and a
final effluent dissolved oxygen (D.O.) concentration of 5 mg/1.
A number of treatment systems were considered. The J. P. Stevens and
Co., Inc. personnel recognized that any system chosen would have a degree of
risk associated with it as none had been applied full-scale 1n the textile
industry. The successful application of multimedia filtration as an advanced
wastewater treatment process in non-textile applications stimulated installa-
tion at Wallace, N. C. The four multimedia filtration units installed are
capable of treating 5 million gallons per day (MGD).
As an effort to go beyond the NPDES requirements and considering possible
future situations, the next logical step was the evaluation of water reuse
1
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within the production facility. A Research Demonstration grant was applied
for from the U. S. Environmental Protection Agency (EPA) to demonstrate the
degree of pollutant removal necessary to meet effluent treatment requirements
which could be achieved with multimedia filtration. A second objective was
to determine if the effluent from the multimedia filters could be further
treated by additional, selected advanced wastewater treatment processes to a
degree suitable to allow reuse within the dyeing and finishing operations.
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SECTION 2
CONCLUSIONS
Full-scale multimedia filtration followed by pilot scale advanced treat-
ment and subsequent reuse trials were evaluated at the Wallace, N. C. plants
of J. P. Stevens and Co., Inc. The conclusions, based on these evaluations,
are:
(1) Multimedia filtration with chemical pre-conditioning was demonstrated
to be a viable means of meeting stringent effluent quality require-
ments for wastewater from two textile plants dyeing and finishing
man-made fiber fabrics.
(2) Alum is a satisfactory primary coagulant for reducing suspended solids,
BODc, COD, TOC, color and other parameters. Low concentrations of
alum were needed and the efficiency of coagulation was improved when
a compatible polyelectrolyte was added. Powdered activated carbon
added under the same conditions reduced BOD5 as well as color. The
increased suspended solids volumes caused by the chemical additions
created solids handling problems.
(3) Multimedia filter effluent treated by chemical coagulation, settling
and filtration followed by treatment through a 5-column train (sand
filter, organic scavenging resin, granular activated carbon, cation
exchange resin and anion exchange resin) produced an essentially
colorless effluent. This water was found satisfactory for dyeing a
full shade range of shades including white and pastels on man-made
fabrics of nylon, polyester, acetate and triacetate.
(4) Nylon and triacetate scavenged residual color very efficiently from
the effluent from the 5-column train. Conversely, polyester and
secondary acetate were found to be much less efficient color scavengers,
3
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(5) The colorfastness of all four fibers dyed with selected dyes and
wastewater treated through the entire treatment sequence, compared
favorably with dyes and fibers processed in the normal manner.
(6) A serious problem of backwash water volume and treatment would re-
sult from a full-scale version of the Mobile Pilot Plant. A one
million gallon-per-day version of this pilot plant was estimated to
generate 235,000 gallons per day of backwash water at one regenera-
tion for each unit each twenty-four hours. The backwash or wasting
volume from each stage is estimated as follows: reactor/clarifier -
5,000 gpd; sand filter - 30,000 gpd; organic scavenging resin column
40,000 gpd; granular activated carbon column - 10,000 gpd; and
75,000 gpd each from the cation and anion exchange columns. Treat-
ment for the backwash and or wasting flow would require more land,
capital and equipment and new wastewater treatment problems would
probably be introduced.
(7) Current operational and amortization costs for the biological and
multimedia filter systems are 40tf and 46tf per thousand gallons,
respectively. The treated process water costs, as supplied to the
manufacturing plant is 4U per thousand gallons. Operating costs
for the advanced waste treatment facility, as estimated by J. P.
Stevens and Co., Inc. and presented in Section 9, is $1.06 per
thousand gallons.
(8) Although the technical feasibility of further treating a biologically
treated effluent to a quality sufficient to allow reuse in critical
processing operations, e.g. dyeing and finishing, has been demon-
strated, the economics of full-scale application are not satis-
factory at the time of this investigation.
(9) The build-up of fine solid materials in the overall system, due to
multimedia filtration, presents a major problem in achieving effluent
total suspended solids values; particularly when effluent standards
require extremely low concentrations.
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SECTION 3
RECOMMENDATIONS
Full-scale multimedia filtration followed by pilot scale advanced treat-
ment and subsequent re-use trials were evaluated at the Wallace, N. C. plants
of J. P. Stevens and Co., Inc. The recommendations, based on these evaluations,
are:
(1) Laboratory bench and pilot scale studies of treating textile dyeing
and finishing wastewater indicated the need for relatively high con-
centrations of alum, polymer and powdered activated carbon, coupled
with long coagulation and/or absorption times for successful treat-
ment. Actual coagulation and/or absorption time between chemical
additions and full-scale multimedia filtration in the plant was
very short, in the range of six to fifteen seconds. Procedures for
improving the coagulation reaction time should be investigated
as a means of increasing the efficiency of pollutant removals in
multimedia filtration.
(2) Color scavenging ability of nylon, polyester, acetate and triacetate
have been investigated. This same investigation should be made on
other fibers and blends of fibers.
(3) Textile plants considering water re-use would be well advised to
segregate highly colored wastes to more effectively treat this lower
volume at a lower overall cost per thousand gallons.
(4) Secondary clarifiers should be equipped with high turbidity alarms on
the effluent outlet to give advanced warning of clarifier upset. This
approach would greatly relieve the possibility of excessive suspended
solids reaching the multimedia filters and permit bringing the waste-
water treatment plant under control more rapidly in case of upset.
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(5) Further Investigation of available organic scavenging resins for their
color removal efficiencies should be made.
(6) Continuous zeta potential readout and continuous monitoring of chem-
ical feed volumes based on pre-determined amounts required to give
desired level of treatment should be studied. Lower chemical costs
and improved control over effluent quality should result.
(7) Available alternatives for eliminating/minimizing the problem of
build-up of recirculated fine solid materials due to multimedia
filtration in the overall system should be evaluated. This may
involve side stream treatment by tertiary type treatment process,
e.g., reverse osmosis.
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SECTION 4
J. P. STEVENS MANUFACTURING FACILITIES
FIBERS AND CHEMICALS USED
J. P. Stevens and Co., Inc. has two manufacturing plants located in
Wallace, N. C. One plant is engaged in the manufacture of warp knitted fab-
rics from various man-made fibers, which are subsequently dyed and finished.
The other plant is solely a dyeing and finishing plant for circular knitted
fabrics, mostly of 100% texturized polyester knits.
Both manufacturing plants have a maximum dyeing and finishing capacity of
approximately 210,000 pounds per day. Average daily production 1s approxi-
mately 75 - 80% of that amount.
Dyeing and finishing by fiber type is as follows:
Fiber or Blend Per cent of Total
100% Polyamide 27.9
100% Polyester 49.9
100% Acetate, secondary 11.1
80%/20% Acetate/Nylon 5.5
95%/5% Polyester/Nylon 2.9
80%/20% Triacetate/Nylon 2.7
100.0
Dyeing is by the exhaustion technique using heat, pressure, adds and carriers,
singly or in one of several combinations, to bring about exhaustion of the
dyes from aqueous solution or dispersion onto and Into the fiber substrate.
The dye 1s 90% - 99% utilized, depending on dye class and application
method; consequently a highly colored process water Is discharged to the waste
treatment system.
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The types of dyeing procedures used include atmospheric and pressure beck
dyeing, atmospheric and pressure beam dyeing, and high temperature jet dyeing.
The dyes used are primarily of the disperse, acid, acid premetallized and
naphthoic classes. Fluorescent brightening agents are also used in addition
to a few basic and direct dyes.
Total dye consumption for both plants exceeds one million pounds per year.
This consumption is further divided by dye class as follows:
Dye Class Percent of Total
Disperse 80.25
Acid/Acid Premetallized 11.53
Fluorescent Brightener 5.33
Naphthoic (diazotized/developed) 2.73
Basic (Cationic) 0.12
Direct 0.04
Total 100.00
A number of chemical auxiliaries are also used in the scouring and/or
dyeing operations, which are sometimes carried out simultaneously. Control of
pH is accomplished primarily by organic acids and organic and inorganic salts.
A variety of surface active agents are employed which scour, level, complex
and promote wetting, lubricity and dye migration.
Special operations for corrective procedures and/or dye fixation often
require the use of chemicals which may cause problems in the waste treatment
plant. The use of these chemicals is closely controlled to prevent effects
in the treatment system, e.g. Mercury and Chromium compounds are not used.
Some Copper and Antimony salts are required for very special dyeing applica-
tions. Color stripping sometimes requires use of a hydrosulfite or hypochlo-
rite. Ammonia and organic nitrogen salts are sometimes used which add to the
influent TKN. Inorganic nitrogen salts are also used in production. It should
be noted, however, that virtually every dye used in these plants is a nitrogen
containing dye which also contributes to a highly refractory (not easily
biologically oxidized) TKN.
8
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Carriers used to promote exhaustion of disperse dye into triacetate and
polyester are of the ester and perch!oroethy!ene types. There are no pheno-
lics, such as orthophenylphenol, biphenyl or chlorinated aromatic carriers
used. These have been replaced by the esters and perchloroethylene.
Finishing consists of the following processes, one or more of which is
applied to all fabrics finished:
. Drying - remove moisture.
. Chemical finish application for aesthetic and/or functional reasons.
. Face finishing - via Schreiner calendering, napping, suedeing, shear-
ing.
. Fix width and length to obtain fabric yield.
. Heat set thermosetting fibers to impart added dimensional stability
and resistance to changes during laundering or dry cleaning.
The chemical additives applied for aesthetics purposes are normally soft-
eners of the cationic and nonionic group, plus polyvinyl acetate and methacry-
late resins for "hand" (texture) improvement. Combinations of aesthetic and
functional finishes are used for special applications such as provided lub-
ricity for napping and suedeing and the desired "hand" or "feel" required by
the customer. Fluorocarbon finishing is an example of a functional finish
for soil release or anti-staining properties. There is no bleaching, bonding,
laminating, flocking or printing done at either of these plants.
BIOLOGICAL WASTEWATER TREATMENT FACILITIES
An extended aeration activated sludge treatment facility, with chlorina-
tion and post-aeration was in operation at the manufacturing facility at the
initiation of the study. An engineering description of each component of the
biological system is presented in Table 1. The normal operating parameters
are presented in Table 2 and a schematic in Figure 1.
A brief description of the treatment sequence is as follows. Wastewater
from two dyeing and finishing plants was screened and discharged Into the
aerated equalization tank. This tank was used for dampening chemical (organic)
and hydraulic surges. Nitrate (as NaNOg) was added to the equalization tank
to provide nutrient to sustain biological activity. The waste was pumped from
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TABLE 1. BIOLOGICAL TREATMENT PLANT ENGINEERING DATA
Flow
.io.yAyzAiL°.N . T-ANK
Detention
Volume
Aerators
AERATION TANKS
Detention
Volume, Total
Aerators Tanks #1 & 2*
MLSS
#BODC/#MLSS
D
* Tank #3: Existing
SETTLING TANKS
Detention
Overflow Rate
Sludge Return
Return: To Aeration
To Mix
CHLORINATION FACILITIES
C12 Dosage
Basin Volume
Contact Time
POST AERATION BASIN
Detention
Volume
Aerators
Units
Hours
MG
Cf
No.
Hp. (Each)
Hrs.
MG
Cf
No.
Hp. Ea.
mg/1
Blowers
Hrs.
GPSFPD
% Range
MGD
MGD
PPM
PPD
MG
Cf
Min.
Hrs.
MG
Cf.
No.
Hp. Ea.
3.0 MGD1
13.2
1.65
224,800.
3
40.
32.3
3.24
433,690.
6
40.
1,800.
.03
7.05
318.
0-75
2.25
1.50
15.
375.
.104
9,792.
50
.70
.0875
11,700.
2
5
5.0 MGD2
8.0
1.65
224,800.
3
50.
19.46
3.24
433,690.
8
40.
3,000.
.03
4.25
531.
0-75
3.75
2.5
15.
625.
.104
9.792.
30
.43
.0875
11,700.
2
5
(continued)
10
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TABLE 1 (continued)
Flow
Units
3.Q MGD
1
5.0 MGD'
SLUDGE DIGESTION
Flow
Tank Volume
MLSS
Sludge Age
Hydraulic Retention
Time
SLUDGE CONCENTRATOR
Flow
Supernatant Flow
MGD
MG
Cf.
mg/1
Days
Days
MGD
.078
.925
123,300.'
22,500.
24.3
11.8
.078
.130
.925
123,300.
38,000.
24.3
7.1
.130
Thru Detention
Overflow Rate
Sludge Holding
EXCHANGER & SOFTENER WASTE
Flow estimated
Detention (both Tanks)
Vol ume
Aeration
SAND BEDS
Number of Beds Existing
New
Total Area - Existing
New
Hours
GPSFPD
Cf.
MGD
Days
MG
Cf.
Cf.
Cf.
10.
81.
5,160.
.12
4.1
.50
66,800.
3
6
3,970.
25,000.
6.
135.
5,160.
.188
2.66
.50
66,800.
Existing Blowers
3
6
3,970.
25,000.
,. , . .,,._,„, ,., — - ... ...
Note 1: Data shown for 3.0 MGD flow commensurate with current operating
conditions.
Note 2: Data shown for 5.0 MGD flow maximum Plant design.
11
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TABLE2. BIOLOGICAL SYSTEM - UNIT PROCESS DESCRIPTION
BIOLOGICAL TREATMENT PROCESS
PROCESS
LOADING RATE
F/M RATIO
MLSS
AERATION BASINS
DETENTION TIME
AERATION
MINIMUM D.O. LEVEL
NUTRIENT FEED
SECONDARY CLARIFICATION
CLARIFIERS
SURFACE AREA
SURFACE LOADING RATE
SIDE WATER DEPTH (SWD)
SURFACE OVERFLOW
SURFACE OVERFLOW
Activated Sludge
17.9 Lbs. BOD/1000 Cu.Ft./Day (Actual)
0.03 (Actual)
6,500 - 8,500 mg/1 (Actual)
2 0 1.62 MG Per Basin
26 Hours 0 3 MGD (Actual)
12 x 40 Hp Aerators = 480 Hp
3.0 mg/1
100 Lbs./Day NQN03 (33.5% Avail. N)
2-75' Circular
4418 Sq. Ft. Each, 8836 Sq. Ft. Total
0.88 Lbs./Sq.Ft./Day (Actual)
13.5 Ft.
318 Gal/Day/Sq.Ft. (Actual)
531 Gal/Day/Sq.Ft. (Max. at 5.0 MGD)
12
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RAW WASTES
CLARIR^RNO.I
AERATION TANK NO.I
TD PRFFK *-• •-—
BASIN(Cf)
1 I
POST
AE-RATION
, ,
i
1
SAND BEDS
SAND BEDS
JLUOGi
CONCENTRATOR
SOLIDS TO LANDFILL
Figure I. Biological treatment system.
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WASTE STREAM CHARACTERISTICS
The average biological effluent, during the period of study is presented
in Table 3. This biological effluent is the influent to the multimedia filters,
TABLE 3. BIOLOGICAL EFFLUENT
Flow
PH
Alkalinity (CaC03)
BOD5
Solids - Total
Dissolved
Suspended
Volatile
Ammonia (N)
Kjeldahl Nitrogen
Nitrate
Phosphorus - Total
Ortho
Total Hardness
Nitrite (N)
Organic Nitrogen
Sulfate
Sulfide
MGD
Units
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
2.9
7.2
98.
10.
750.
668.
20.
82.
0.5
2.1
0.1
15.4
.13
15.
.03
1.6
82.
<1.
Chloride
Fluoride
Aluminum
Antimony
Calcium
Chromi urn
Cobal t
Copper
Iron
Magnesium
Manganese
Mercury
Potassium
Sodium
Tin
Zinc
Phenols
Surfactants
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
28.0
0.4
1.0
1.0
2.7
.07
.1
.05
1.73
1.7
.05
<.0005
5.0
99.
.3
.28
.05
0.5
RECEIVING STREAMS
The Stevens waste treatment plant (WTP) discharges into Little Rockfish
Creek which flows into Big Rockfish Creek and then into the Northeast Cape Fear
River. Little Rockfish Creek, Big Rockfish Creek and the Northeast Cape Fear
River are Class C streams. (See Figure 2) A description of both Little and
Big Rockfish Creeks is presented in Table 4.
14
-------
STEVENS
.WASTE
TREATMENT.
.PLANT
CLASS-C
LITTLE ROCKFISH CREEK
NOT TO SCALE
Figure 2. Receiving stream network in relation to wastewater treatment plant outfoll.
15
-------
TABLE 4. CHARACTERISTICS OF RECEIVING STREAMS
UPSTREAM OF WASTEWATER TREATMENT PLANT DISCHARGE
CHARACTERISTICS
Drainage Area
Flow Average
10 Year - 7 Day Low
Temperature
Year Average
Avg. June-July-Aug.
Avg. Dec-Jan-Feb.
pH Average - Year
D.O. - Average Year
Avg. June-July-Aug.
Avg. Dec-Jan-Feb.
BOD Average Year
Avg. June-July-Aug.
Avg. Dec-Jan-Feb.
COD Average Year
Avg. June-July-Aug.
Avg. Dec-Jan-Feb.
TOC Average Year
Avg. June-July-Aug.
Avg. Dec-Jan-Feb.
C( F)
mg/1
mg/1
mg/1
mg/1
LITTLE
ROCKFISH
CREEK
11.
5.2-7.8
0.00-0.03
14 (58)
22 (72)
8 (46)
7.2
8.4
7.4
8.7
2.3
3.2
1.8
28
26
25
16
34
9
BIG
ROCKFISH
CREEK
150.
71.0-97.0
0.16-0.63
15 (59)
23 (74)
8 (47)
6.9
8.6
7.5
9.4
2.9
2.9
2.8
79
83
75
28
29
20
Note: All Stream Data except flow and drainage area compiled from J. P.
Stevens & Co., Inc. stream sampling and testing above Waste Treat-
ment Plant effluent outfall. This data is reported to the North
Carolina Department of Environmental Management monthly.
16
-------
the equalization tank to dual aeration units and to aeration tank #3. Aera-
tion tank #3 was a part of an earlier contact activated sludge plant. The
biologically treated wastewater was clarified and chlorinated. Effluent from
the chlorine contact tank was aerated to 6-8 mg/1 dissolved oxygen (D.O.) prior
to discharge into Little Rockfish Creek. Aeration was necessary, as much of
the year there was very little flow in the receiving stream. Residual chlorine
in the effluent was below 0.5 mg/1.
Waste sludge and scum were pumped to an aerated sludge digester. Sludge
from this digester flowed to a sludge concentrator and to sand beds for drying
and final disposal to landfill.
Flow through the plant averaged approximately 2.9 MGD. All structures
were designed for 5 MGD, but aeration equipment and floating aerators in the
mix tank were provided for 4.0 MGD. When the 4.0 MGD flow was exceeded, or
when additional aeration capacity was required, additional aerators were to be
purchased and installed. Wiring and concrete pads on lagoon bottoms were al-
ready in place to accomodate additional and/or larger aerators as required.
17
-------
SECTION 5
WASTEWATER TREATMENT PLANT OPERATIONAL CONSIDERATIONS
EFFECT OF CLARIFICATION ON MULTIMEDIA FILTRATION
The biological wastewater treatment system included two main secondary
clarifiers, each seventy-five feet in diameter and having a 13.5 foot side
wall water depth. Operating these clarifiers at a 3 MGD flow rate, with a
mixed liquor suspended solids level of 7,000 - 7,500 mg/1, severely taxed the
clarifiers. A change in flow to 3.5 MGD would require reduction of MLSS to
5,500 - 6,000 mg/1 in order to maintain the same degree of secondary effluent
quality. It was estimated that flow much above 3.5 MGD would require addition
of a third secondary clarifier.
Efficient secondary clarification was absolutely essential to satisfactory
performance of the multimedia filter tertiary wastewater treatment process.
Poor secondary clarifier performance taxed the complete system. The multi-
media filters were blinded very rapidly when secondary clarification was poor.
This blinding caused excessive backwash requirements for the filters. A "chain
reaction" was unleashed; the increased number and frequency of backwashes empty-
ing into the equalization lagoon caused increased wastewater flow into aeration
and subsequently to the secondary clarifiers. The poor clarification already
in progress was made worse and the wastewater treatment plant efficiency was
drastically reduced within a matter of two hours to the point that final ef-
fluent limits were exceeded and stream standards were violated. This condition
had to be corrected at once to prevent an untenable situation - curtailment of
the dyeing and finishing operations in both manufacturing plants.
The biological plant was designed with a large equalization lagoon and two
large aeration lagoons. These three lagoons were normally operated at less
than capacity. These lagoons provide approximately 1,250,000 gallons of
18
-------
temporary wastewater storage which could be used to quickly bring the system
under control. This procedure was effectively demonstrated on several occa-
sions. To control this chain reaction, the first step was to quickly reduce,
by seventy-five percent, the wastewater entering the secondary clarifiers.
This reduction was accomplished by partially closing the two hand-controlled
gate valves which controlled wastewater flow by gravity to each clarifier.
Under seventy-five percent reduced flow, the clarifiers efficiency was dras-
tically improved within approximately fifteen minutes. After fifteen to thirty
minutes, flow was increased gradually over a two to four hour period, until
full flow was being satisfactorily clarified.
ADDITIONAL PROCESS DESIGN FEATURES
Three other design features in this biological system were vital to
successful operation, and gave quick recovery from low clarifier solids re-
moval efficiency. The first was a standby sludge redrculatlon pump piped to
both clarifiers which could be used for either clarifier in the event of a
sludge recirculation pump failure and which could also be operated to supple-
ment sludge removal by the other two during a period of poor secondary clari-
fier performance. The sludge is pumped from secondary clarification to the
headend of each aeration lagoon. The second was a clarifier drain pump; the
importance of this small pump, common to both secondary clarifiers, cannot be
overstated; it was used to draw off excessive concentrated sludge from the
bottom of either or both clarifiers when clarification was less efficient.
The primary purpose of this drain pump was to drain, or partially drain, either
clarifier when problems occurred in that equipment. The third was a high
turbidity alarm on the influent to the multimedia filters used to warn of high
solids losses from the secondary clarifiers which would over-tax the filters,
and eventually the entire system, if not brought under control quickly.
SUMMARY
The key to efficient and satisfactory operation of the multimedia filters
was satisfactory, efficient, suspended solids removal by the secondary clari-
fiers. This point cannot be overstressed. The multimedia filters gave best
19
-------
pollutant and color removal performance, with or without chemical additions
into the waste stream ahead of the filters, when their influent was secondary
clarified wastewater containing low suspended solids.
20
-------
SECTION 6
MULTIMEDIA FILTRATION
INTRODUCTION
The overall project consisted of three major efforts. The first being
the operation and evaluation of the full-scale multimedia filtration; second,
the operation of advanced waste treatment operations on bench and pilot scale
to achieve water of manufacturing reuse quality as discussed in Section 7; and
third, the reuse trials in laboratory scale, to determine if the treated
effluent could be reused as discussed in Section 8.
OBJECTIVE
The objective of the operation of the multimedia filtration system, with
or without chemical addition, following secondary biological treatment and
chlorination, was to produce an effluent whose quality would meet stream
standards and all effluent conditions imposed by the State of North Carolina
and the National Pollutant Discharge Elimination System permit administered
by the U. S. Environmental Protection Agency. This approach carried a high
degree of risk. Table 5 provides multimedia filter engineering design criteria
for this full-scale installation, designed for a maximum 5 MGD wastewater flow.
LOCATION
The location of the multimedia filtration system is shown schematically
in Figure 3. A relatively small portion of the land area devoted to waste-
water treatment was needed for this tertiary treatment, however, a substantial
improvement in wastewater effluent quality was effected.
21
-------
TABLE 5. MULTIMEDIA FILTRATION DESIGN CRITERIA
5 MGD MAXIMUM FLOW
Influent Pumps:
Number Each 3
Horsepower Hp 40
Flow, Each gpm 1,800
Total Dynamic Head Ft. 60
Backwash Pumps:
Number Each 2
Horsepower Hp 125
Flow, Each gpm 7,000
Total Dynamic Head Ft. 49
Surface Wash Pumps:
Number Each 2
Horsepower Hp 15
Flow gpm 200
Total Dynamic Head Ft. ' 153
Water Supply Pumps:
Number Each 3
Horsepower Hp 5
Fl ow gpm 80
Total Dynamic Head Ft. 129
Flow Measurement: Filter Influent
Type Magnetic Flow Meter
Range MGD 0-8
Size Inches 12
Function Indicate, Record, Totalize
Mixed Media Filters:
Number Each 4
No. in operation at one time - Each 3
Application Rate G> 5.0 MGD GPSFPD 3.5
Length Ft. 30
Diameter Ft. 10
Surface Wash-Each Filter Provided
(continued)
22
-------
TABLE 5. (Continued)
Chemical Feed to Filters Provided:
Alum:
Liquid Alum Storage Tank Volume Gal.
No. Positive Displacement Pumps Each
Polyelectrolyte:
Tanks Provided: 250 Gallons Mix
Feed
Pumps Each
Carbon:
Storage Tank Volume Gal.
Day Use Tank Volume Gal.
Feed Pumps No.
Transfer Pump No.
Recirculation Pump No.
Clear Backwash Water Storage (Existing)
Volume Gal.
Number of Filter Backwashes
Post Aeration Tank:
Vol ume
Surface Aerators - on
Horsepower
hand
Gal.
No.
Each
Flow Measuring: Plant Effluent
Measuring Device
Size
Function
4000
2
1
1
2
18,000
1,500
3
1
1
69,000
1
145,000
2
5
Ft.
Parshall Flume
Indicate, Record, Totalize
3.0
23
-------
RAW WASTES
MIX
TANK
AERATION TANKNO.I JCLARIFIER NO.I
u
AERATION
TANK "
AERATION TANK N0.2
j
]
FILTER
BLDG.
['DIVERSION
BOX
BASIN(CD
BASIN(B.W.)
i
1
t
I
SAND BEDS
1
SAND BEDS
/SLUDGI
CONCENTRATOR
SOLIDS TO LANDFILL
Figure 3. Biological treatment system .with multi-media filter.
-------
DESIGN/OPERATION
The system was designed with influent pumps, backwash pumps, and surface
wash pumps for a 5 MGD flow. Filter effluent exited under pressure and was
gravity fed to the final aeration tank where the dissolved oxygen was increased
to 6.5 - 8.5 mg/1 before discharge to the receiving stream.
Each multimedia filter was thirty feet long, and ten feet in diameter.
The four filters were installed horizontally and operated in parallel. Approx-
imately twenty-seven feet of each filter extended outside the building and
was exposed to the ambient environment. This arrangement posed no problems
with freezing since relatively mild winters are the norm in this Southeastern
North Carolina location. Ambient temperatures are seldom below -4°C (25°F).
The piping and valve network, turbidimeters, flowmeters, control panel, chem-
ical feed pumps and lines, alum storage, polymer make-up and feed tanks, and
carbon slurry day storage tank are all housed inside a building with heat
available in extremely cold weather.
Flow to each filter was measured and controlled by metering the required
amount of secondary effluent to each of the three filters kept on-line to treat
the approximately 3.0 MGD flow. Normally, a fourth filter would be backwashed
and placed on stand-by. However, 1f the characteristics of the secondary
effluent were such that shorter filter runs were prevalent then all four fil-
ters could essentially be run at the same time. This was possible due to the
fact that the backwash cycle took only 20 minutes from initiation to comple-
tion. Typically, the filters were set to backwash on a timed cycle of 24
hours, but each filter was also set to backwach on a high headloss override
control. The headloss override was set to backwash each filter at eleven
feet of headloss. The backwash flow rate was set at 5,500 gpm; the total
backwash flow was approximately 40,000 gallons. Seventeen analog computer
controlled valves had to be opened and/or closed from initiation to completion
of the backwash cycle and bringing the filter back on line.
Analysis of solids in samples taken at the intervals shown, on the total
backwash effluent line, for a selected filter backwash are shown in Table 6.
25
-------
TABLE 6. ANALYSIS OF SOLIDS
Minute
1
5
8
Total
Solids
mg/1
1,720
875
655
Total
Volatile Solids
mg/1
1,265
520
330
Total
Suspended Solids
mg/1
1,536
560
372
Total Volatile
Suspended Solids
mg/1
1,208
444
272
Backwash water from the filters was returned by gravity to the equalization
tank and again treated through the complete biological, chlorination, and
tertiary filtration sequence. Backwash water was stored in a 87,500 gallon
tank adjacent to the filter building. When the pre-set stored backwash stor-
age water level was lowered, this tank was refilled by gravity flow, from
multimedia filter effluent, from a splitter box located underground between the
multimedia filter building and the post-aeration tank.
An end view of a multimedia filter is shown in Figure 4. Each filter was
partially filled by twenty-eight tons of concrete which served as an anchor
for tank stability and a base for support gravel and the underdrain system.
A total of fifteen inches of varying size gravel was added on top of the
concrete and made up the support bed and underdrain system. A total of thirty-
six inches of four separate media added in length was placed above the gravel,
hence the term multimedia filter. Filter influent was applied from the top
through distribution laterals. The four media were stratified from coarse
to fine from the top to the bottom. The mode of operation was to remove by
physical filtration increasingly smaller particles as the wastewater, under
pressure, was forced down through the increasingly finer media. Addition of
coagulating chemicals was planned to improve efficiency by changing the phy-
sical form of pollutants into a form better removed by physical filtration.
The addition of powdered activated carbon slurry improved pollutant removal
by adsorption of pollutants on the carbon particles and also Improved sub-
sequent physical filtration.
26
-------
16" INFLUENT HEADER
SURFACE WASH ARM
2"
ANTHRACITE
S.G. 1.45-1.5 MEDIA
ANTHRACITE
S.G. 1.5 MEDIA
S.G. 4.2 MEDIA
S.G.2.6 MEDIA SAND
UNDERDRAIN
LATERAL
CONCRETE
FILL
GARNET
HIGH DENSITY
SUPPORT
16" UNDERDRAIN
HEADER
3/8"x3/l6"
SILICA GRAVEL
3/4"x3/8"
SILICA GRAVEL
-I l/2"x 3/4"
SILICA GRAVEL
MEDIA LEVEL
1
2
3
4
S.G.
1.45 - 1.5
1.5
2.6
4.2
MEDIA TYPE
ANTHRACITE
ANTHRACITE
SAND
GARNET
U.C.
< 2.1
< 1.7
< 1.8
<2.0
MESH SIZE
- 4 to * 1 4
-8 to +20
+ 10 to +40
+ 30 to +70
Figure 4. Multi-madia filter, end view.
27
-------
MULTIMEDIA FILTER SOLIDS HANDLING
One of the most important operational considerations was the removal of
suspended solids. Approximately seven hundred pounds per day of suspended
solids were removed from the secondary clarifier effluent by subsequent multi-
media filtration. This had the definite effect of greatly improving effluent
quality and upgrading the receiving stream. The effective removal of effluent
solids also created a definite degrading effect on the biological plant. The
reason for this was the return of filter backwash solids to the influent to
the biological system and retaining the solids in the treatment plant. Solids
recirculation, removal by secondary clarification, removal by multimedia fil-
tration, concentration, drying and ultimately disposal of dried sludge became
major operating problems. At one point, suspended solids had accumulated to
the level that sludge drying on the beds was not adequate to dewater it quickly
enough. It was necessary to remove sludge from the thickener by front-end
loader and haul away by dump truck.
Because of this serious solids handling problem, a dewatering polymer, at
approximately 200 mg/1 concentration, was added in-line downstream of the pump
which carried sludge from the concentrator to the drying beds. The addition
of this dewatering polymer greatly speeded dewatering, drying and removal of
dried sludge from the drying bed. Sludge drying time was reduced from six
weeks to two weeks in good weather. Use of this dewatering polymer has been
continued in order to help keep solids levels under control in the biological
treatment plant. Later a special front-end loader attachment was obtained
which allowed mechanical cleaning of dried sludge (approximately 25 - 30% dry
weight of sludge solids) from the drying beds. The removed dried sludge was
emptied into a solid waste container and land filled for disposal. It should
be noted that even in rainy weather, good sludge dewatering can usually be
accomplished within approximately two weeks in summer and three to four weeks
in winter because cracking of the beds begins within twenty-four hours which
allows rain water to drain away quickly. The only serious problem experienced
was when very heavy rainfall pulverized wet or drying sludge and prevented
cracking and quick drying; under those most adverse circumstances, some beds
were not emptied sooner than six weeks, even when the dewatering polymer was
used.
28
-------
MULTIMEDIA FILTER POLLUTANT REMOVAL
The multimedia filters were employed both with and without prior chemical
conditioning of the biologically treated effluent.
Without Chemical Addition
Table 7 shows monthly averages of pounds per day of BOD5, COD and TSS,
and Pt-Co Units of color removed by multimedia filtration without chemical
addition. Removal was by physical filtration of suspended particles from the
secondary clarified, chlorinated wastewater stream. It is apparent from this
data that the multimedia filters were very effective in removal of pollutants
by simple physical filtration. The average ratio of pounds of suspended solids
to BOD5 removed from January, 1974 through April, 1975 was 7.4:1, and the
ratio of suspended solids to COD was 5.3:1. Expressed in another way, removal
of one pound of suspended matter gave a resulting average daily removal of
0.19 pounds of COD and an additional 0.14 pounds of BODg. Color removal by
this physical filtration was only an average of 41 Pt-Co Units of color or
about 15% of the total color remaining after secondary clarification and chlor-
ination. This low removal of color indicated a large amount of water soluble
color.
Average pounds of pollutants remaining in the final effluent after physical
treatment via multimedia filtration, without chemical addition, has been com-
pared in Table 8 to the 3-stage NPDES Permit requirements for each parameter.
The average residual color (Pt-Co) has been included for the same sixteen
month period. All first stage (1/74-6/75) parameter averages were achieved
except for one-month's averages for ammonia and oil and grease; the oil and
grease value was suspected to be much lower and was attributed to analytical
problems. Second stage (7/75-6/78) parameter averages would have been achiev-
ed for all but BOD5 (five months) and suspended solids (four months). The
monthly range in average pounds per day of BODc and suspended solids removed
via physical filtration was significant. Daily removals of BODg ranged from
29 to 145 pounds and averaged 91 pounds per day based on monthly averages.
The monthly average pounds per day of suspended solids removed ranged from 236
pounds to 948 pounds and averaged 671 pounds. These average daily pounds re-
moved illustrate the achievement of NPDES Permit parameter requirements.
29
-------
TABLE 7. POUNDS PER DAY POLLUTANTS PLUS AMOUNTS OF COLOR REMOVED VIA
MULTIMEDIA FILTRATION (TERTIARY TREATMENT) WITHOUT CHEMICAL ADDITION
YEAR/MONTH
1974
January
February
March
April
May
June
July
August
September
October
November
December
1975
January
February
March
April
BOD5
Lbs/Day
118
81
83
99
71
135
145
43
54
29
92
63
124
67
136
112
COD
Lbs/Day
706
670
740
1064
368
1962
2620
1358
1634
904
974
1502
1595
689
1913
1614
SS
Lbs/Day
236
393
344
570
948
539
781
644
864
663
907
593
838
646
925
849
Pt-Co
Units
Before
195
253
241
257
380
376
262
238
300
240
280
170
250
175
340
301
UNITS COLOR
Units
After
177
198
201
230
346
300
232
222
250
210
245
147
223
163
240
223
REMOVED*
Total
Units
18
55
40
27
34
76
30
16
50
30
35
23
27
12
100
78
Apparent color; run on unfiltered sample.
30
-------
TABLE 8. AVERAGE POUNDS POLLUTANTS AND PT-CO UNITS OF COLOR REMAINING IN
FINAL EFFLUENT AFTER MULTIMEDIA FILTRATION (WITHOUT CHEMICAL ADDITION)
COMPARED TO 3-STAGE NPDES PERMIT REQUIREMENTS
Yr./
Mo.
BODC SS
D
TKN PHOS.
T
Cr.
T
Zn.
NH-
Sb. Cu. O&G Phenols Color
1974
Jan.
Feb.
Mar.
Apr.
May
June
July
Aug.
Sept.
Oct.
Nov.
Dec.
205
146
168
203
251
305
272
161
140
166
241
162
377
254
173
376
271
359
370
262
303
438
502
423
172
98
90
123
129
135
171
108
117
130
133
92
151
120
135
162
211
182
100
184
133
166
190
155
1.5
1.1
1.2
1.1
1.1
1.0
1.4
0.9
1.1
1.2
1.3
1.1
3.7
4.4
5.5
9.6
9.2
4.9
6.8
7.7
7.7
8.8
5.5
4.7
8
7
7
15
14
14
29
14
16
9.8
7.7
7.3
28
39
24
39
24
20
24
38
28
31
13
24
1.8
1.9
1.6
2.1
2.7
2.0
2.8
3.9
3.0
2.5
2.6
2.8
447
123
112
103
435
341
930
252
268
24
46
87
1.8
2.9
1.6
1.7
1.6
1.0
4.6
2.0
2.3
2.7
9.2
5.2
225
346
300
232
222
246
210
245
153
1975
Jan.
Feb.
Mar.
Apr.
164
162
213
170
353
323
436
393
97
99
121
120
174
213
72
92
1.1
0.6
0.6
0.7
5.6
5.9
5.3
8.1
11.2 11
6.5 11
6.4 16
9.7 10
2.0
1.6
0.9
0.8
195
237
170
41
3.4
3.1
1.2
1.9
223
163
240
223
Average 196 351 121 153 1.1 6.5 11.4 24 2.2 238
2.9
233
NPDES PERMIT EFFLUENT REQUIREMENTS: STAGE 1 was for the period 1/74 - 6/75;
STAGE 2 period was 7/75 - 6/78; STAGE 3 period 7/78 - 12/78 (*TKN may
be higher provided permittee can show no resulting deleterious effects
to stream biota or to stream quality).
STAGE
1
2
3
375
210
210
1013
417
417
285
285
83*
225
225
225
4
4
2
.7
.7
.0
21
21
12
.5
19
46
46
79
79
21
5.0
6.7
0.8
713
9.6
9.6
4.0
31
-------
The range in average pounds per day removed is more significant in light
of biological treatment plant performance. A number of reasons have been cited
why biological treatment plant performance varies. The presence of this tert-
iary treatment step downstream of the secondary clarifiers provided an addi-
tional safeguard in meeting NPDES Permit requirements and protecting the re-
ceiving stream. For comparison purposes, the concentrations of BODc, COD, SS
(in milligrams per liter) and color (in Pt-Co Units) are given both before and
after multimedia filtration, along with the average, standard deviation and
coefficient of variation (CV) in Table 9. The CV is particularly useful in
measuring the relative variation in more than one set of data. From the data
in Table 9, it can be readily seen that the CV decreased for each of the para-
meters, indicating a more stable, consistently good quality effluent.
With Chemical Addition
There were three major factors which prompted additional investigations
into optimization of the multimedia filtration process by chemical addition.
The need for additional removal of suspended solids is evident from the data
in Table 8, in order to comply with second and third stage NPDES Permit require-
ments. It was also important to determine the level of total Kjeldahl nitrogen
(TKN) attainable. The effluent limits prescribed were thought to be practi-
cally unachieveable even with chemical addition. In order to reuse the water
in dyeing, it was thought that greater than 90% of the color had to be removed.
It was necessary to determine the practical limits of color removal by multi-
media filtration with chemical addition in order to minimize the amount of
additional color removal necessary in subsequent pilot scale treatment.
During the period when the multimedia filter installation was operated
without chemical additives, laboratory bench work investigations with chem-
icals were performed. Alum was evaluated as the primary coagulant. Various
polymeric coagulant aids were evaluated to find one or more which would great-
ly enhance the flocculating effects of alum 1n this particular waste stream.
Powdered activated carbon slurry was evaluated alone and in combination with
alum and alum/polymer at various concentration levels to determine what levels
of removal of various pollutants and color could be achieved.
32
-------
TABLE 9. EFFICIENCY OF MULTIMEDIA FILTRATION - WITHOUT CHEMICAL ADDITION
PARAMETERS
CONCENTRATION
AFTER SECONDARY
BIOLOGICAL TREATMENT
BODC COD SS COLOR
Pt-Co
CONCENTRATION AFTER
MULTIMEDIA FILTRATION
BODC COD SS TOC COLOR
Pt-Co
PERCENT REMOVAL BY
MULTIMEDIA FILTRATION
BOD5 COD SS COLOR
Pt-Co
co
CO
YEAR/MO
mg/1 mg/1 mg/1 units mg/1 mg/1 mg/1 mg/1 units
1974
January
February
March
April
May
June
July
August
September
October
November
December
1975
January
February
March
Average
Sta. Dev.
C.V.
13.7
9.8
11.2
12.8
14.0
18.6
17.0
8.1
8.3
8.0
13.0
9.3
12.8
10.6
16.4
12.33
3.24
.26
320
265
264
326
304
367
403
285
314
288
304
282
310
261
358
311.12
39.45
.13
26
28
23
40
53
38
47
36
50
45
55
42
53
45
64
44.06
11.91
.27
195
253
241
257
380
376
262
238
300
240
280
170
250
175
340
8.7 290
6.3 236
7.5 231
8.6 281
10.9 288
12.9 284
11.1 296
6.4 231
6.0 244
6.8 251
9.4 266
6.7 220
7.3 239
7.5 229
10.0 268
8.39 256.
2.00 25.
.24
16.0
11.0
7.7
15.9
11.8
15.2
15.1
10.4
13.0
17.9
19.6
17.5
15.7
15.0
20.5
44 15.08
31 3.55
10 .24
87
71
70
72
76
77
89
73
82
99
98
85
77
78
89
177
198
201
230
346
300
232
222
250
210
245
147
223
163
240
36.5
35.7
33.0
32.8
22.0
36.0
34.7
20.5
27.7
15.0
27.7
28.0
43.0
29.2
39.0
9.4
10.9
12.5
13.8
5.3
22.6
26.6
18.9
22.3
25.3
12.5
22.0
22.9
12.3
25.1
38.5
60.7
66.5
60.3
77.7
60.0
67.9
70.8
74.0
60.2
64.4
58.3
70.3
66.7
68.0
9.2
21.7
16.6
10.5
8.9
20.2
11.4
6.7
16.7
12.5
12.5
13.5
10.8
6.9
29.4
-------
Effect of Alum on Raw Influent Wastewater
Laboratory bench-scale studies were carried out on raw influent waste-
water from dyeing and finishing to determine whether alum and alum/poly-
electrolyte dosages could effect any significant removals of color, turbidity,
COD, or TOC. This investigation was made to determine particularly whether
significant color reductions could be realized; if so, then consideration
would have been given to massive color reductions ahead of biological treat-
ment.
Alum dosages of up to 200 mg/1 alone (as alum), and with 1.5 ITKJ/I of a
catibnic polyelectrolyte were used (See Table 10). All samples were filter-
ed through glass fiber filters after mixing and settling in order to determine
the greatest possible reductions by subsequent filtration in the four para-
meters investigated. This series of experiments yielded largely negative re-
sults. Color was not reduced in any of the eleven individual tests. Turbidity
was not reduced when alum alone was used, and only a ten percent reduction when
1.5 mg/1 of a cationic polyelectrolyte was added. Addition of alum alone
gave COD reductions averaging approximately five percent, and only about ten
percent when 1.5 mg/1 of the cationic polyelectrolyte was added along with the
alum. TOC results were interesting; there was no appreciable removal with
alum or alum/polyelectrolyte if alum dosages were 125 mg/1 or less. However,
when alum dosages were increased to the 150 mg/1 and 200 mg/1 level there
were eight and twenty-three percent reductions, respectively, in TOC values.
Following this laboratory exercise, experiments were designated to deter-
mine whether massive doses of alum (200 to 1,000 mg/1) would make any differ-
ence in color, turbidity, COD and TOC values. These parameters were tested on
both filtered and unfiltered samples which had previously been treated with
various alum dosages. Results were recorded in Table 11. Color reduction was
not achieved in the unfiltered samples at any alum dosages; however, at
400 mg/1 alum and higher, when samples were filtered, color was reduced from
800 to 500 Pt-Co Units, This reduction 1n color was not enough to prompt
consideration of color removal ahead of biological treatment. Indications
are that some organic dyes had been coagulated, but 1n a very fine floe which
was not readily visible and which did not settle but was removed by filtration.
Turbidity was generally increased as alum dosage increased, whether samples
34
-------
TABLE 10. RAW WASTE RESPONSE TO ALUM & TO ALUM/POLYELECTROLYTE DOSAGES
CO
tn
SAMPLE #
1
2
3
4
5
6
7
8
9
10
11
12
pH (units)
6.8
6.2
6.3
6.1
6.0
5.9
6.4
6.1
6.2
6.2
5.7
6.2
ALUM (mg/1)
0
75
75
100
100
125
125
150
150
200
200
0
POLYELECTROLYTE
mg/1
0
0
1.5
0
1.5
0
1.5
0
1.5
0
1.5
1.5
COLOR
Pt-Co
Units*
700
700
700
700
700
700
700
700
700
700
700
700
TURBIDITY
JTU
73
74
67
72
65
87
66
73
68
78
74
73
COD (mg/1)
1152
1128
1072
1112
1040
1112
1120
1192
1120
1080
1040
1136
TOC (mg/1)
328
336
320
325
295
328
317
302
284
254
289
295
True colors; run on filtered sample.
Mix: Rapid Mix 2 minutes @ 125 RPM; Add polyelectrolyte; Slow mix 25 Min.
minutes.
Filtration: Reeve Angle Glass Fiber Filters; 7.0 cm.
Temperature: 12°C. Due to refrigeration prior to experimentation.
Polyelectrolyte: Nalco 627, CatioMc polyelectrolyte
25 RPM. Settle 15
-------
TABLE 11. RAW WASTE RESPONSE TO ALUM
SAMPLE
Number
1
2
3
4
5
6
7
8
9
10
11
12
ALUM
mg/1
0
200
400
600
800
1000
0
200
400
600
800
1000
PR
Units
7.0
6.0
5.1
5.1
5.1
4.8
7.0
6.0
5.1
5.1
5.1
4.8
Pt-Co
COLOR
Units*
800
800
800
800
800
800
800
800
500
500
500
500
TURBIDITY
JTU
82
97
125
125
125
125
62
75
70
72
86
93
COD
mg/1
1120
1104
1040
1048
1056
1016
1088
1072
640
632
736
776
TOC
mg/1
374
342
250
302
316
312
344
320
236
225
246
Broke
*
Filtered samples yield true color; unfiltered yield apparent color.
Mix: Rapid mix 2 minutes @ 125 RPM; Add Alum; Slow mix @ 20 RPM - 25 M1n.
Settle 15 minutes.
Floe: Virtually no floe noted in any sample.
Temperature: 12°C.
Filtration: Samples 1-6 decanted. Samples 7-12 filtered through 934AH Reeve
Angle glass fiber filter, 7 cm.
36
-------
were filtered or unftltered. Based on these results, it was decided to use a
filtered rather than decanted sample in evaluating chemical addition pollutant
removal efficiency, as the filtered sample was thought to be more nearly repre-
sentative of the full-scale multimedia filter performance and provide a more
consistent evaluation of results.
COD reductions on the unfiltered samples amounted to approximately five
to ten percent when alum dosages were increased beyond 200 mg/1. The COD re-
ductions on the filtered samples were approximately forty percent at 400 and
600 mg/1, but only approximately thirty percent at 800 and 1,000 mg/1 alum.
These removals indicate some definite chemical coagulation had taken place.
Like COD removal, 200 mg/1 alum had little effect on TOC removal. However, at
400 mg/1 alum, TOC removal was approximately sixteen percent on the unfilter-
ed samples and approximately thirty percent on the filtered samples.
This series of experiments indicates explicitly that alum, even in ex-
tremely large dosages, would not exert a significant pollutant reduction.
Significant pollutant reduction by alum treatment of raw influent wastewater
was not expected however, because of the high amounts of soluble pollutants
such as acid and basic dyes and other soluble organlcs. Had this approach
worked to give reductions of color, TOC and COD of more than fifty percent,
coagulation and settling ahead of biological treatment would have been con-
sidered.
Effect of Alum on Secondary-Clarified, Non-Chlorinated Wastewater
Laboratory jar tests were made on secondary-clarified, non-chlorinated,
wastewater using only alum as a primary coagulant. The plan was to determine
maximum coagulation efficiency using alum and then to determine in a later
series of bench tests what additives might improve the coagulation efficiency
of alum. Two series of tests were made; the first was alum added tn 100 or
200 mg/1 increments to 600 mg/1, and the second was alum added in 50 mg/1
increments to 250 mg/1 as shown in Table 12.
Maximum color and COD removal was obtained at 200 mg/1 additions of alum
to 600 mg/1 gave no further removals. BODg was only significantly affected
at 400 mg/1. Greatest removal efficiency was obtained with 150 mg/1 alum;
37
-------
TABLE 12. LABORATORY EXPERIMENTS - EFFECTS OF ALUM ON POLLUTANT REDUCTIONS
CO
00
SAMPLE # ALUM Pt-Co
mg/1 COLOR
Units*
*
a
b
c
d
Al
2
3
4
5
6
Bl
2
3
4
5
6
True color;
. Flash mix
20 minutes
0
50
100
200
400
600
0
50
100
150
200
250
320
240
160
60
80
80
280
280
240
80
60
40
run on filtered
2 minutes
. Filter
. Filter through 7.0
. Initial Waste pH 7.
. BODC deter
mi nations
& 125
•
% COLOR TURBIDITY
REMOVED JTU
0
25
50
81
75
75
0
0
14
71
79
86
sample.
RPM. Add Alum
1.
1.
1.
0.
0.
0.
1.
3.
7.
2.
1.
1.
mix
cm 934AH Reeve Angle Glass
0
3
5
7
7
9
5
1
5
1
2
2
5 minutes
Fiber Fi
COD
mg/1
228
204
176
100
100
104
208
208
180
96
84
88
. Mix
Iter.
TOC BODc
mg/1 mg/1
8
8
7
8
1
1
114 7
78 6
72 9
42 5
38 2
36 7
.5
.5
.3
.6
.3
.3
.0
.3
at 20 RPM 5 minutes
.i\
OBSERVATIONS
FLOC
None
Cloudy
Pin
Large
Large
Large
None
None
Pin
Large
Large
Large
. Settle
2 Temperature 12°C.
: 15%
Samole. Not Sf
•eded
-------
although slightly higher removals of BOD5, COD and color could be obtained at
200 and 250 mg/1. The incremental removal efficiency at these higher dosages
was not considered to be economically feasible.
There was one encouraging observation from these experiments. Pin floe
(very small, poor settling floe) was noted at approximately 100 mg/1 alum.
This indicated that lower alum dosages added to the wastewater ahead of the
multimedia filters would give a pin floe which would be captured by the denser
filter media layers. Consideration was given to the fact that BOD5 removals
were poor in these two similar experiments. The most plausible reason for this
was the fact that laboratory experiments had shown that 84% of the BODC was
D
soluble and, therefore, the type not likely removed by coagulation. Addition-
ally, the BOD5 test itself likely did not adequately differentiate BOD5 from
sample to sample at this very low concentration.
pH Versus Alum Coagulation Efficiency
Laboratory bench-scale experiments were conducted to evaluate the effect
of pH on color and pollutant removals when 150 mg/1 alum was used on the bio-
logically-treated, secondary-clarified, non-chlorinated wastewater. As ex-
pected, color and other pollutants were generally coagulated and removed with
greater efficiency as pH was lowered to 6,0, but data indicated going below
6.0 pH would be of questionable value. Unfiltered blanks were compared with
the filtered blanks. Color was generally not affected simply by filtering.
However, reductions in other pollutants were noticeable. See Table 13.
Chlorinated Vs. Non-Chlorinated Hastewater
Laboratory jar tests were conducted to determine whether significant dif-
ferences in pollutant removals would be evident when comparing secondary-
clarified, biologically-treated wastewater, chlorinated vs. non-chlorinated.
This study was conducted for two reasons, It was necessary to know whether
chlorinated, secondary-clarified wastewater could be treated with alum,
powdered activated carbon, and various polyelectrolytes to yield a floe suit-
able for removal by multimedia filtration. If the chlorinated wastewater
could not be so treated, then it would be necessary to relocate the chlorlna-
tion facility downstream from the multimedia filters, just prior to final
39
-------
TABLE 13. EVALUATION OF COLOR AND POLLUTANT REMOVALS WITH 150 mg/1 ALUM AT VARIOUS pH'S
-P.
o
SAMPLE
Al
2
3
4
5
6
B1
2
3
4
5
6
*
True
Note:
ALUM
$ mg/1
0-Unf
0-
150
150
150
150
0-Unf
0
150
150
150
150
Pt-Co
COLOR^
Units
300
280
160
120
60
80
320
320
160
160
80
120
color; run on filtered
Samples A-l
and B-l are
% COLOR
REMOVAL
0
7
47
60
80
73
0
0
50
50
75
63
sample.
unf i 1 tered
TURBIDITY
JTU
15.0
6.2
4.9
4.0
0.8
0.9
3.8
2.1
4.5
3.7
1.4
0.9
blanks for
COD
mg/1
304
256
148
124
100
96
332
308
208
188
168
160
comparison.
BODr
mg/T
20.8
7.6
4.8
5.2
4.8
5.2
9.2
5.2
5.2
4.4
3.6
4.8
PH
Units
7.3
7.3
7.0
6.5
6.0
5.2
7.3
7.3
7.0
6.5
6.0
5.5
OBSERVATIONS
FLOC
None
None
Large
Large
Large
Large
None
None
Large
Large
Large
Large
Procedure:
a. Add Alum and rapid mix @ 125 RPM 2 minutes.
b. Reduce mixing to 50 RPM - Adjust pH (HCL).
c. Reduce mixing to 20 RPM and mix 25 minutes.
d. Settle for 15 minutes.
e. Filter Supernatant through 934 AH Reeve Angle Glass Fiber Filter, 7.0 cm.
-------
aeration and discharge. This study revealed no differences significant enough
to warrant evaluating only non-chlorinated, secondary-clarified wastewater.
See Tables 14 and 15 for comparative color, COD and TOC results.
Prior laboratory studies had shown that 150 mg/1 alum was needed to sig-
nificantly and consistently reduce color in this wastewater. Additional eval-
uations were conducted using alum and powdered activated carbon to combine
several investigations into one: (1) chlorinated versus non-chlorinated
secondary wastewater; (2) powdered activated carbon dosages of 10 to 300 mg/1;
and (3) 100 mg/1 alum dosages with powdered activated carbon. Results of
these investigations are summarized in Tables 14 and 15. Several major find-
ings resulted from these investigations. In this particular wastewater, color
was well removed when 150 mg/1 alum was used but very poorly removed when alum
dosages were lowered to 100 mg/1, even when powdered activated carbon was used.
It was evident that polymeric coagulant aids must be evaluated to greatly im-
prove alum efficiency for color removal; these investigations were made in a
later series. The pollutant removal efficiency of powdered activated carbon
in the jar tests was quite poor; even massive dosages gave only limited color
removals. COD and TOC removal efficiencies by powdered activated carbon
additions were judged economically infeaslble; removals via alum or alum/
polymer coagulations required further investigations for optimization to im-
prove the economics of removal.
The data in Tables 14 and 15 provide some very interesting Insights into
pollutant removals in this particular waste. The 150 mg/1 alum dosage re-
moved approximately 5Q% of the COD and TOC, and 60-70% of the color. However,
even 100 mg/1 powdered activated carbon gave only a 20-30% additional reduc-
tion 1n these parameters. This 100 mg/1 dosage of powdered activated carbon,
considering the incremental removal, was considered economically prohibitive.
Pollutant Removal By Powdered Activated Carbon Alone
Powdered activated carbon was evaluated alone to determine its effective-
ness for pollutant removal. This would determine whether interference from
alum had been a factor in the previous Investigations. The results of these
investigations are given in Table 16. Powdered activated carbon dosages of
100 mg/1 were required to effect significant removals. Powdered activated
carbon dosages of 200 mg/1 had no additional significant effect on color» COD
41
-------
TABLE 14. LABORATORY EXPERIMENTS - EFFECTS OF ALUM AND POWDERED ACTIVATED CARBON ON
NON-CHLORINATED, SECONDARY CLARIFIED, BIOLOGICALLY TREATED HASTEHATER
ro
ALUM
SAMPLE f mg/1
1
2
3
4
5
6
7
8
9
10
11
12
0
150
150
150
150
150
0
150
150
150
150
150
*
True color; run
PAC
mg/1
0
,0
10
25
35
50
0
0
100
150
200
300
on filtered
Pt-Co
COLOR
Units*
200
80
80
80
80
80
240
80
60
40
40
30
sample.
TURBIDITY
JTU
2.2
2.1
2
2
2
2
3
2
2
2
2
2
.2
.2
.4
.2
.3
.8
.4
.8
.4
.1
COD
mg/1
248
124
116
108
116
100
224
112
80
76
60
40
TOC
mg/1
80.
41.8
40.6
35.5
40.3
45.8
80.9
38.8
35.5
26.5
25.6
20.8
OBSERVATIONS
No floe
Med floe;
Med floe;
Med floe;
Med-large
Med-large
No floe
Med floe;
Med floe;
Med floe;
Med floe;
Med floe;
slight settling
some
some
floe
floe
settl
settl
; good
ing
ing
settling
; good settling
slight settling
good
good
good
good
settl
settl
settl
ing
ing
ing
settling
Notes
a.
b.
c.
d.
Flash nix alum
slurry added -
2 minutes & 125 RPM; Carbon slurry added = Mix 5 minutes & 125
Mix 5 Minutes i 2- RPM; Settle 20 minutes.
Filter samples through 934AH 7.0 on
Initial pH of waste sample
Temperature of
all samples
7.3 for
15°C.
Reeve
Angle
samples 1-6;
Glass Fiber
and 7.5 for
Filter.
samples
7-12.
RPM; Alum
e. PAC with Uestvaco Aqua Nuchar A.
-------
TABLE 15. LABORATORY EXPERIMENTS - EFFECTS OF ALUM AND POWDERED ACTIVATED CARBON
CO
*—
a.
b.
c.
d.
e.
SAMPLE #
1
2
3
4
5
6
7
8
9
10
n
12
ALUM PAC
mg/1 mg/1
0 0
150 0
150 25
150 35
150 50
150 100
150 150
150 200
150 300
100 25
100 50
100 100
Pt-Co
COLOR TURBIDITY
Units JTU
280
80
80
100
100
60
80
40
20
200
200
200
True color; run on filtered sample
Flash mix 2 minutes @ 125 RPM; Carbon slurry
Mix 5 minutes
\
OBSERVATIONS
No floe
Pin floe;
Med floe;
Med/large
Med/ large
Med/large
Med/large
Med/large
Med/large
Pin floe
Pin floe
Pin floe
some
good
floe;
floe;
floe;
floe;
floe;
floe;
RPM; Alum slurry
settling
settli
good
good
good
good
good
good
added
ng
settl i ng
settling
settl i ng
settling
settling
settling
•
-------
TABLE 16. COLOR, TURBIDITY, COD, TOC, REMOVED BY POWDERED ACTIVATED CARBON ADDITION
SAMPLE #
1
2
3
4
5
6
7
8
9
10
11
12
PAC
mg/1
0
25
50
100
150
200
250
300
350
400
450
500
Pt-Co
COLOR
Uni ts*
200
200
200
120
80
120
20
20
-
30
' -
40
TURBIDITY
JTU
2.2
2.5
3.8
5.3
2.0
17.0(1)
0.8
0.7
-
0.7
-
0.8
COD
mg/1
204
204
196
144
100
148
100
84
_
96
_
88
TOC
mg/1
79.8
76.0
77.5
61.0
47.5
49.5
31.8
29.0
_
27.0
_
28.0
OBSERVATIONS
FLOC
None
None
None
Pin
Good
Good
Small
Pin
—
Small
—
Small
True color; run on filtered sample.
(1) Floe broken by handling.
Procedure: Rapid Stir 1 Minute. Add PAC, stir 2 minutes @ 125 RPM, Stir 28 Minutes & 20 RPM.
Settle 30 Minutes. Filter through 7.0 cm Diam. 934AH Reeve Angle Glass Fiber Filter.
Powdered Activated Carbon: Hestvacp Aqua Nuchar A.
-------
and TOC. Dosages of 300 mg/1 did effect greater removals. Dosages of 400 and
500 mg/1 provided significant improvement. Regression equations were fitted
to the data in Table 16. These were of the form y=a+bx. Correlation coeffi-
cients as a measure of "goodness of fit", were developed for color, COD and
TOC (Samples 1-9); these were 0.94, 0.91 and .98 respectively. The correlation
values indicate a very strong correlation and consistent results.
Experiments other than those presented in Table 16 gave similar results,
even when a contact time of four hours was used. A telephone communication
with the technical service group of a major powdered activated carbon supplier
gave the response that 100 mg/1 of powdered activated carbon would be about
the maximum dosage which could be economically considered. With this particu-
lar wastewater, earlier laboratory results had shown that greater color and
pollutant removals were obtained using alum at 150 mg/1 than with large carbon
dosages. Should no other chemical system prove practical, then the most im-
portant consideration for full-scale application ahead of the multimedia filter
was the evaluation of powdered activated carbon cost versus the cost and In-
convenience of coping with extremely large amounts of alum sludge.
Further tests were made with another PAC Slurry. The results of this
carbon (Sample B) were compared with the carbon used in the previous inves-
tigations (Sample A). From Table 17, it is apparent that Sample A carbon
is superior to Sample B carbon in all respects. Therefore, it was decided
to use only Sample A carbon or its equivalent in further laboratory and
full-scale plant trials.
Alum/Polymer Dosages for Color and Pollutant Removals
A series of laboratory experiments was carried out to study further the
effects of alum, alum/polymer and polymer alone on color and pollutant removals
from secondary treated wastewater. Care was taken to use samples with varying
color. Previous tests had shown that chlorination had no unsatisfactory effect
on results; however, chlorinated wastewater was not used to assure that waste-
water color was unaffected by chlorine oxidation. The type and amount of dye
varied throughout the day, and from day to day, in the wastewater from the man-
ufacturing plants. On any given day, the color 1n the secondary wastewater
would be affected more or less by the amount of soluble dyes present.
45
-------
TABLE 17. EVALUATION OF POWDERED ACTIVATED CARBON ALONE AS A COLOR
AND POLLUTANT REMOVAL CHEMICAL
SAMPLE #
Al
2
3
4
5
6
7
Bl
2
3
4
5
6
7
PAC
mg/1
0-Unf
0-F
25
50
100
200
400
0-Unf
0-F
25
50
100
200
400
Pt-Co
COLOR
Units*
500
500
300
300
200
200
200
500
500
400
400
300
300
150
% COLOR
REMOVED
0
40
40
60
60
60
0
20
20
40
40
70
TURBIDITY
JTU
9.0
7.8
3.5
3.7
4.5
4.6
5.5
120.
7.7
8.6
9.0
9.7
COD
mg/1
400
356
284
268
256
232
192
484
448
444
412
392
340
272
BOD5
mg/1
28
23
23
22
22
21
TOC
mg/i
105
92
81
79
82
64
182
167
166
161
156
143
118
*
Filtered samples yield true color; unfiltered yield apparent color.
Note: 1. Sample A's run using Westvaco's Powdered Activated Carbon
NUCHAR AQUA A.
2. Sample B's run using Westvaco's Powdered Activated Carbon
C-190-N.
3. Samples A-l and B-l are unfiltered blanks (no PAC).
4. Samples A-2 and B-2 are filtered blanks (no PAC).
5. Temperature of Wastewater 22°C (72°F).
6. Wastewater pH 7.2 on A series and 7.5 on B Series.
Running Procedure:
a. Add powdered activated Carbon - Rapid mix at 125 RPM -
2 minutes.
b. Reduce mixing speed to 20 RPM for 25 minutes.
c. Settle 15 minutes.
d. Filter supernatant through 7.0 cm. 934AH Reeve Angle Glass
Fihpr Filter.
46
-------
Color and pollutant removals in this particular series of laboratory ex-
periments was by chemical coagulation and settling, except for filtration of
some samples for comparison evaluation. The data is presented in Table 18.
Careful attention should be given the data in Tables 18, 19 and 20, in order
to compare color and pollutant removals with varying amounts of alum and/or
polymeric coagulant aid. The cationic coagulant aid used was chosen after
preliminary evaluation of a number of such materials in the laboratory.
Color removal by alum alone was best at 125-150 mg/1, as had been pre-
viously determined for this particular waste. The tremendous increase in color
removal by addition of cationic coagulant polymer was of particular intertst;
addition of 1.5 to 2.5 mg/1 polymer effected much greater removals than alum
alone; the use of 5 mg/1 gave no further improvement. Indications were that
1.5 mg/1 or less polymer could likely be used with good results in the more
dynamic full-scale multimedia filter plant.
COD removal by alum was enhanced by polymer addition. It was interesting
to note that a doubling of alum/polymer concentration gave essentially a
doubling of COD removal. The percentages of BODg removal were higher at the
75 mg/1 alum and 1.5-2.5 mg/1 polymer dosages than were percentages of COD
removed. Furthermore, as the alum level was doubled, the COD removal was less
than doubled. The fact that most samples in this series were simply settled
and decanted for testing as opposed to settling and filtration through glass
fiber filter medium likely added to the less obvious concentration shifts.
As with color removal, BOD5 and COD removals were not increased by in-
creasing coagulant aid polymer concentration. Of particular Importance 1s the
fact that addition of only the coagulant aid polymer without alum resulted 1n
no visible floe formation and no removal of color, BODg and COD. To the con-
trary, the use of polymer only gave an Increase in BODg and COD concentrations
which was an indication the polymer itself exerted an oxygen demand.
The major concern was to determine what additional color and pollutant
removals could be obtained in full-scale filtration and determine what problems
would have to be overcome to meet requirements for all stages of the NPDES
Permit (See Table 21) and to produce a more economically treated, low color
wastewater which would be further treated in the pilot studies 1n an attempt
to produce water suitable for reuse 1n dyeing and finishing.
47
-------
TABLE 18. EVALUATION OF ALUM AND ALUM/POLYMER DOSAGES ON COLOR
AND POLLUTANT REDUCTIONS IN BIOLOGICALLY-TREATED, SECONDARY-CLARIFIED,
NON-CHLORINATED WASTEWATER
SAMPLE #
1
2
3
4
5
6
7
8
9
10
11
12
CATIONIC Pt-Co
ALUM POLYMER COLOR % COLOR TURBIDITY COD
mg/1 mg/1 Units* REMOVED JTU mg/1
0 - 320 21.8 308
75 - 320 0 9.2 284
75 2.5 320 0 4.3 260
100 - 300 6 18.0 272
100 2.5 280 13 4.5 256
125 - 320 0 12. 256
125 2.5 200 38 4.6 220
150 - 240 25 17.0 216
150 2.5 160 50 4.9 196
150 5.0 200 38 5.9 216
0 2.5 320 0 5.0 328
0 5.0 380 19+ 5.6 348
BOD5
mg/1
8.8
5.6
5.6
4.8
4.4
5.2
4.0
3.6
4.0
4.8
12.0
11.2
PH
Units
7.0
6.9
6.8
6.8
6.6
7.0
6.8
6.5
6.7
6.7
7.1
7.2
Apparent color; run on unfiltered sample.
Note: 1.
2.
3.
4.
5.
6.
Procedure:
a.
b.
c.
d.
Samples NOT Filtered.
Alum alone produced a good floe which settled well.
Alum and polymer caused floe to form large clumps which settled
rapidly.
Polymer alone produced no visible floe.
Wastewater Temperature 21 °C (70°F).
Polymer used was Nalco 627.
Add chemical under rapid mix conditions (125 RPM).
Rapid mix 2 Minutes @ 125 RPM.
Slow mix 20 Minutes @ 25 RPM.
Settle 30 Minutes. Decant supernatant for testing.
48
-------
TABLE 19. EVALUATION OF ALUM AND ALUM/POLYMER DOSAGES ON COLOR AND
POLLUTANT REDUCTIONS IN BIOLOGICALLY-TREATED, SECONDARY-CLARIFIED,
NON-CHLORINATED WASTEUATER
SAMPLE
1
2
3
4
5
6
7
8
9
10
11
12
#
CATION 1C Pt-Co
ALUM POLYMER COLOR % COLOR TURBIDITY COD
mg/1 mg/1 Units* REMOVED OTU mg/1
0 0 420 1.2 256
75 0 350 17 2.5 232
75 2.5 350 17 1.6 216
100 0 300 29 3.3 212
100 2.5 250 40 1.9 200
125 0 200 52 3.9 200
125 2.5 280 33 5.1 172
150 0 350 17 19.0 172
150 2.5 280 33 6.0 156
150 5.0 280 33 6.8 156
0 2.5 420 0 4.9 268
0 5.0 420 0 5.5 268
TOC
mg/1
96
89
71
77
63
77
72
69
64
70
106
106
BOD5
Units
7.3
7.1
7.3
7.0
7.3
6.9
6.6
6.7
6.5
6.6
7.1
7.1
Apparent
Notes :
1.
2.
3.
4.
5.
6.
Procedure:
a.
b.
c.
d.
color; run on unflltered sample.
Samples NOT Filtered.
Alum alone produced a good, well settling floe.
Alum/Polymer floe formed large clumps which were very rapidly
settled.
Polymer alone produced no visible floe.
Temperature of wastewater was 21 °C (70°F).
Polymer used was Nalco 627.
Add chemicals under rapid mix conditions (125 RPM).
Rapid mix 2 Minutes @ 125 RPM.
Slow mix 25 Minues @ 20 RPM.
Settle 30 Minutes. Decant supernatant for testing.
49
-------
TABLE 20. EVALUATION OF ALUM AND ALUM/POLYMER DOSAGES ON COLOR AND
POLLUTANT REDUCTIONS IN BIOLOGICALLY TREATED, SECONDARY CLARIFIED,
NON-CHLORINATED WASTEWATER
SAMPLE
1
2
3
4**
5
6**
7
8**
9
10**
11**
12**
13**
#
CATIONIC Pt-Co
POLYMER COLOR % COLOR TURBIDITY COD
mq/1 mg/1 Units* REMOVED OTU mg/1
0-Unf 0 500 0 25.0 450
0-F 0 500 0 22.0 400
75 0 300 40 18.0 328
75 1.5 200 60 10.0 304
100 0 300 40 18.0 316
100 1.5 200 60 9.0 260
125 0 300 40 16.0 260
125 1.5 100 80 5.8 196
150 0 100 80 6.0 200
150 1.5 125 63 5.8 168
150 2.5 125 63 6.1 168
0 1.5 300 40 9.2 368
0 2.5 300 40 9.5 360
TOC
mg/1
123
104
81
86
65
79
75
80
70
69
122
130
BODc
mil
•r
28.0
27.5
29.5
22.0
24.0
*
Filtered
Notes: 1.
2.
3.
4.
5.
6.
7.
Procedure:
a.
b.
c.
d.
e.
samples yield true color; unfiltered yield apparent color.
* Denotes samples which could NOT be filtered.
Alum produced a large, light floe.
Alum/ polymer floe was very large and did not settle well.
Polymer alone produced no visible floe.
Temperature of wastewater used for 22°C (72°F).
Polymer used was Nalco 627.
Clarifier effluent used was very highly colored, cloudy, and
contained high suspended solids (not measured).
Add chemicals under rapid mix conditions (125 RPM).
Rapid mix 2 Minutes @ 125 RPM.
Slow mix 25 Minutes @ 20 RPM.
Settle 15 Minutes. Decant supernatant.
Attempt to filter all decanted supernatants through 7.0 cm 934AH
Reeve Angle Glass Fiber Filter.
50
-------
TABLE 21. NPDES DISCHARGE REQUIREMENTS. 3 - STAGE PERMIT
STAGE
PERIOD:
PARAMETERS:
FLOW MGD*
BOD5
T.S.S.
T. Kjeldahl Nitrogen
T. Phosphorus
T. Chromium
T. Zinc
Ammonia
Antimony
Copper
Oil and Grease
Phenols
1
1/74-6/75
Average
Pounds/Day
5.0 MGD*
375
1,013
285
225
4.7
21
19
79
5
713
9.6
2
7/75-6/78
Average
Pounds/ Day
5.0 MGD*
210
417
285
225
4.7
21
46
79
6.7
-
9.6
3
7/78-12/78
Average
Pounds/Day
5.0 MGD*
210
417
83
225
2.0
12.5
46
21
0.8
-
4.0
Stage 1: Average Pounds Per Day shown for Discharge 002 - Wastewater Treat-
ment Plant Effluent only. The other three discharges not included.
Stages 2 & 3: All four discharges are combined into a single discharge.
Discharges are: Boiler Blowdown, Wastewater Treatment Plant, Acid/Brine
Discharge and Cooling Water Overflow Discharge.
51
-------
Pilot Media Filter Chemical Evaluation
Following extensive laboratory evaluations of a large number of coagulant
aids and polymeric primary coagulants, a polymer manufacturer offered a 2-gpm
pilot media filter for a dynamic evaluation of various polymeric coagulants,
alum and combinations of alum and polymers. This unit was operated on site
inside the filter building.
Secondary, chlorinated wastewater was taken from the influent to the multi-
media filters and fed to the 2-gpm pilot filter. Several interesting observa-
tions were made during this three-day investigation. First, a dosage of 4 mg/1
of a cationic polymeric coagulant did act as a primary coagulant and did re-
duce BOD5 by approximately 40% (from 7.2-4.0 mg/1). Turbidity was reduced 75%
from 16-4 JTU. However, two disadvantages were quickly apparent; within two
hours, the media filter was plugging and headloss was increasing rapidly.
After two and one-half hours, the pilot filter was inoperable and was complete-
ly plugged with a jelly-like floe. Indications were this floe would be almost
impossible to dry as sludge on a conventional sand bed.
The second observation was that while only 4 mg/1 of cationic polymeric
coagulant gave significant BOD5 and turbidity removals, others at up to 50 mg/1,
with and without 0.5 mg/1 non-ionic polymeric filter aid chemicals, effected
little or no such removals. The third significant observation was that 100 mg/1
alum with 0.05 mg/1 of a non-ionic polymeric coagulant aid gave best BODg and
turbidity reductions, 60% (from 7.4-3.2 mg/1) and 80%(from 14 to 3 JTU), re-
spectively. Although a large floe rapidly built up and blinded the pilot media
filter, this floe was not nearly so gelatinous as the floe produced by a
cationic polymeric primary coagulant.
The most significant of all was that this 2-gpm pilot media filter had
demonstrated that a dynamic pressure multimedia filter was capable of efficient
pollutant removals despite the very short time chemicals were in Intimate con-
tact in the wastewater stream going Into the filters. The next step was to
demonstrate significant increases in pollutant and color removals in the full-
scale multimedia filtration plant.
52
-------
Multimedia Filter Operation 3 M6D Scale
Laboratory studies using the 2-gpm pilot media filter showed that 100-150
mg/1 alum or 75-125 mg/1 alum plus a small amount of polymeric coagulant aids
did effect very large reductions of BOD5, COD, TOC and color from this par-
ticular wastewater after secondary treatment. Some pin-floe had been observed
at 35-50 mg/1 alum; this was encouraging toward reducing alum feed to the full-
scale multimedia filters. Communications with several equipment suppliers,
knowledgeable 1n wastewater treatment, Indicated multimedia filtration of this
secondary-clarified wastewater would not be satisfactorily accomplished on a
full-scale operational basis using alum as a primary coagulant, primarily be-
cause of the effect on extended aeration activated sludge treatment lagoons
and the lack of storage and handling of filter backwash water. Initial dosages
of 50-150 mg/1 liquid alum ahead of the multimedia filters produced a very
unsatisfactory condition. This condition was characterized by a heavy, yellow
skum which covered the aeration lagoons and also by a larger volume of p1n-
floc which was not removed in secondary-clarification and which qutckly In-
creased solids loading and shortened filter runs on the multimedia filters.
It was obvious that the successful continuing operation of the biological
treatment system with chemical treatment, using liquid alum addition for more
efficient coagulation ahead of multimedia filtration, would be dependent on
(1) reducing the amount of alum or (2) preparing an alternate and relatively
expensive way of handling multimedia filter backwashes and the resulting high
volume of heavy chemical (alum) sludge.
Multimedia filter backwashes were returned to the equalization tank at
the head of the biological treatment plant. Excessively high alum dosages
ahead of the filters upset the biological system by several actions, namely
(1) increased ionic concentrations in the waste, (2) Increased alum sludge
"filter fines", (3) increased skum on aeration lagoons, (4) Increased hydrau-
lic loading on the secondary claHflers, and (5) Increased mixed liquor sus-
pended sol Ids concentration which further reduced treatment efficiency.
Through further in-practice experiments, 1t was determined that liquid
alum dosages should best be kept at 5-10 mg/1 1n order not to create un-
necessary biological system upsets. This was an example of not being able to
53
-------
carry out in a full-scale production operation what was found in the laboratory
to be a viable way of significantly reducing such effluent parameters as BOD^,
COD, TOC, suspended solids and color. It also signaled the requirement for a
tremendous color removal requirement in the pilot wastewater reuse study.
Residual color was the largest single obstacle to the reuse of this particular
wastewater in the dyeing and finishing operations.
The chemical addition locations are shown in Figure 5. Note that all
chemicals were pumped directly into the wastewater influent line to the filters.
The in-line turbulence of the influent wastewater, under pressure from the
pumps, provided the needed mixing and chemical dilution and enhanced rapid
contact between added chemicals and suspended particles in the wastewater.
For a total flow of approximately 2,000 gpm to three filters in operation at
approximately 700 gpm per filter, the in-line contact time for chemicals was
approximately 6.3 seconds to the first filter, and approximately 16 seconds
to the fourth filter. This very short contact time was demonstrated to be
adequate for coagulation to take place. Contact time for chemicals used in
laboratory experiments was usually 15-30 minutes; however, contact times as
long as four hours were used on some investigations. The longer contact
times made no discernable difference. Evaluation and experimentation led
to the liquid alum/polymeric coagulant aid/powdered activated carbon slurry
combinations shown in Table 24. Other evaluations were conducted, but were
not included where dosages varied up to 35 mg/1 alum, 2 mg/1 polymer, and
30 mg/1 PAC. Chemical feed rates of alum were increased during periods of
poor secondary clarifier efficiency.
Average pounds per day of BODg, COD and suspended solids as well as Pt-Co
Units of color computed as monthly averages have been shown in Table 22. These
removals by physical/chemical means are compared 1n Table 23 to removals by
physical means.
Pollutant and color removal percent efficiency have been shown in Table 24.
The tremendous range in percent removals from month to month resulted from
physical/chemical process efficiencies which were at least in part dependent on
secondary clarifier efficiency and the nature of the waste. Secondary clari-
fier efficiency has previously been characterized as dependent on such
influences as weather, operator attention, nature of waste, design, etc.
54
-------
U1
U1
INFLUENT
D
POLYELECTROYTE
PUMP
POLYELECTROTTE ALUM
MIX TANK PUMP
D
-d
ALUM
TANK
RECIRCULATION
PUMP
CARBON
STORAGE
TANK
TRANSFER
PUMP
CARBON
MIX
TANK
CARBON
PUMP
FILTER *l
FO.TER 2
FILTER^
FILTER *4
TO POST
AERATION
Figure 5. .Chemical addition points.
-------
TABLE 22. POUNDS PER DAY POLLUTANTS PLUS AMOUNTS OF COLOR REMOVED VIA MULTIMEDIA
FILTRATION (TERITARY TREATMENT) WITH CHEMICAL ADDITION
01
POLLUTANTS REMOVED
YEAR/MONTH BOD5 COD SS
Lbs/Day Lbs/Day Lbs/Day
Pt-Co
COLOR REMOVED
Units Units Units
Before After Total
CHEMICAL FEED
POLYMER
ALUM NONIONIC ANIONIC PAC
mg/1 mg/1 mg/1 mg/1
1975
May
June
July
August
September
October
November
December
1976
January
February
March
April
May
^*J
June
July
•» « - j
August
September
October
November
December
86
106
77
83
72
84
236
403
271
240
169
164
138
150
112
109
no
134
95
111
1410
817
1387
1705
1546
1505
2464
3738
3310
2965
1668
1856
1635
2375
2509
1865
1522
1728
1748
580
406
1028
879
995
509
1363
2412
1184
1324
901
1073
818
1481
1290
1352
871
1464
879
1013
269
233
234
219
195
196
204
243
255
220
252
244
215
261
265
249
263
277
248
257
215
189
146
160
152
159
153
165
183
163
209
204
165
193
185
198
215
224
229
201
54
44
88
59
43
37
51
78
72
57
43
40
50
68
80
51
48
53
19
56
5
5
5
5
5
5
5
10
10
10
10-15
10
10
10
10
10
10
10
10
10
.05
.05
.05
.05
.05
.05
.05
.05
.05
.1
.1
.1
-
2
2
2
2
2
2
4
4
4
0.1-1.
.1
.05
-
.1
.1
.1
.1
.1
-
36
36
36
15
15
15
35
35
35
35
0
25
10
10
10
10
i f\
10
* f\
10
-------
Likewise, these same things as well as backwash cycle and concentrations/ratios
of chemicals affect multimedia filter performance.
TABLE 23. INCREASED COLOR & POLLUTANT REMOVALS IN RESPONSE
TO CHEMICAL ADDITIONS
Average Lbs/Day Avg. Lbs/Day Removed Percent Increased
Removed By By Physical/Chemical Removal By
P hy s i c a 1 T r e ajtme n t Treatment Chemical Additions
BOD5
COD
S Sol Ids
Color
*Except color.
91
1,270
671
41
measured in Pt-Co Units.
148
1,888
1,091
55
63%
49%
63%
34%
In Table 24, chemical dosages during the first eight months were charac-
terized by 5 mg/1 alum, very small amounts of nonionic filter aid, 2 mg/1
anionic polymeric coagulant aid and 15 to 35 mg/1 of powdered activated carbon.
During the remaining twelve months, chemical dosages were primarily 10 mg/1
alum, very small amounts of each polymer type and usually 10 mg/1 PAC. In
Table 25, the differences in percent removals have been shown as a function
of chemical dosages.
TABLE 25. FILTER EFFICIENCIES AS A FUNCTION OF
DIFFERENT FEED RATES
8-Months
12-Months
mg/1 mg/1 mg/1 mg/1
Alum Nonionic Anionic Carbon
5 .05 2 15-36
10 0-0.1 0.1 10-35
Percent Removals
BOD5 COD SS Color
47.0 25.5 80.7 25.2
53.9 30.7 86.8 21.3
The data given in Table 25 showed three important trends, namely:
(1) increased alum dosages resulted in noticeably more BODg, COD and suspended
57
-------
TABLE 24. EFFICIENCY OF MULTIMEDIA FILTRATION - WITH CHEMICAL ADDITION
Ul
00
AFTER SECOnOMNf
BIOLOGICAL TREATMENT
PARAMETERS
YEAR/ MOUTH
1975
Hay
June
July
August
Septenfcer
October
Novwiber
Decenber
1976
January
February
March
April
«ay
June
July
August
September
October
November
December
BODs
mq/1
11.3
10.7
8.8
7.8
6.1
7.8
16.1
26.3
21.8
15.7
13.0
14.1
9.9
10.4
9.6
9.8
8.3
10.3
10.2
12.6
COO
mil
287
224
229
238
209
231
302
386
384
321
292
297
294
283
280
243
231
_
316
330
SS
mg/1
39.5
27.3
52.5
43.0
44.7
26.8
64.0
111.0
57.3
61.8
43.2
53.0
41.0
71.3
60.0
74.0
45.0
78.3
49.0
54.6
Pt-Co
COLOR
Units
269
233
234
219
195
196
204
243
255
220
252
244
215
261
265
249
263
277
248
257
B0t>5
n
-------
solids removals; (2) more color removal was effected by the higher powdered
activated carbon dosages; and (3) excellent removals of BOD5, COD, suspended
solids and color removals were obtained by reasonably small amounts of chem-
icals confirmed by results from Table 23.
One of the reasons for adding chemicals ahead of the multimedia filters
was to demonstrate that average daily National Pollutant Discharge Elimina-
tion System Permit requirements for all stages could be met. Data for a
twenty-month period when these particular evaluations were carried out has
been shown in Table 26. All first stage requirements were met except for
ammonia during a two-month period; it was felt that this was strictly an
analytical problem since no other data approached violation status and there
should not have been any ammonia present in the effluent from such an oxida-
tion treatment system with greater than two-days detention time where nitri-
fication had been previously shown to take place. All second stage require-
ments were met except for BODg during December and January. Both months were
characterized by periods of extremely cold weather, and during both months
permit requirements were met on the majority of days. Scattered dally viola-
tions, particularly the two days following Christmas vacation when the man-
ufacturing plants did not operate for a nine-day period, were responsible for
this. This underscores earlier statements to the effect that (1) multimedia
filter efficiency was directly linked to secondary clarlfler efficiency and
(2) a build-up of a very fine suspended solids in the biological system, as
did happen over the nine-day vacation period, hampered efficiency and caused
increased BOD5 levels in the effluent.
The third stage permit requirements which must be met in the future are
subject to some further discussion. Average dally permit requirements for
TKN were not met during seven of the twenty months 1n this segment of the
study period. Effluent TKN requirements for the third stage were set seventy-
one percent lower (285 to 83 Ibs/day) than for the first and second stage re-
quirements. It was thought that TKN 1n the final effluent was sufficiently
refractory (biologically Inactive) to assure that no significant deleterious
effects would occur in the receiving streams as a result of the discharge.
The final effluent contained approximately 200 Pt-Co Units of color; virtually
every dye used in both manufacturing plants contained organic Nitrogen.
59
-------
TABLE 26. AVERAGE POUNDS PER DAY POLLUTANTS REMAINING IN FINAL EFFLUENT
AFTER PHYSICAL/CHEMICAL TREATMENT VIA MULTIMEDIA FILTRATION WITH
CHEMICAL ADDITION COMPARED TO THREE-STAGE NPDES PERMIT REQUIREMENTS
YEAR/MONTH
1975
May
June
July
Aug
Sept
Oct
Nov
Dec
1976
Jan
Feb
Mar
Apr
May
June
July
Aug
Sept
Oct
Nov
Dec
AVG.
Lft
O
CO
159
130
134
102
84
103
148
243
252
148
141
171
109
83
117
96
76
86
120
175
134
SUSPENDED
SOLIDS
294
196
227
140
157
131
167
273
189
203
129
193
147
117
143
199
137
212
154
227
182
H-
117
119
103
76
64
67
79
108
142
72
57
164
58
105
57
57
58
64
72
57
85
co
O
0.
1-'
150
119
170
121
155
93
91
121
86
114
148
164
182
141
184
191
183
161
148
136
143
T, CHROMIUM
0.7
0.7
0.7
0.7
0.8
1.0
0.7
0.7
0.7
0.7
0.8
0.8
0.7
0.8
0.8
0.9
0.8
0.7
0.6
0.9
0.8
o
z
t— <
M
H-^
8.5
5.7
5.4
2.0
3.2
2.2
2.4
4.6
3.5
3.1
4.3
3.2
2.0
4.7
5.3
1.8
2.9
2.2
1.8
3.1
3.6
j
6.6
6.6
11.9
9.4
9.8
11.9
12,0
9.8
7.2
7.4
14.3
30.9
30.4
17.9
9.5
6.3
6.7
7.7
6.3
6.8
11.5
•-«
I'-
ll.!
11.0
23.9
29.6
25.8
17.9
28.7
12.3
24.0
21.0
17.0
29.7
22.6
26.9
22.7
30.4
17.9
10.7
29.5
18.0
21.5
OL
LU
CL
O
0.8
0.8
1.5
1.3
4.5
1.5
1.3
0.7
1.0
1.3
1.4
2.1
2.3
2.0
2.2
2.3
2.8
2.1
2.5
2.9
1.9
PHENOLS
4.7
2.4
3.2
2.1
1.6
2.2
2.9
1.6
3.0
2.3
1.9
1.6
1.5
2.8
1.2
1.2
0.2
0.2
0.7
0.2
1.8
ft^ Q
00
0 0.
215
189
146
160
152
159
153
165
183
163
209
204
182
193
187
198
217
224
229
201
186
NPDES
Permi
7/75-6/78;
Stage
1
2
3
375
210
210
t Effluent Requirements:
Stage
1,013
417
417
3 was
285
285
*83
Stage
1 was
12/73-6/75;
Stage
2 was
7/78-12/78.
225
225
225
4.7
4.8
2.0
21.0
21.0
12.5
19
46
46
79
79
21
5.0
6.7
0.8
9.6
9.6
4.0
-
-
-
*TKN may be higher provided permittee can show no deleterious effects on
stream biota and water quality.
60
-------
Furthermore, a tremendous number of chemicals used in normal dyeing and finish-
ing in the textile industry contain organic Nitrogen. A thirty-day long term
aeration study was made comparing (a) 100% final effluent wastewater and
(b) 75% final effluent wastewater with 25% made up of water taken upstream of
the plant discharge. Results of these two parallel studies have been shown in
part in Table 27. The final effluent was found almost completely refractory
and presented evidence for modification negotiations with regulatory agencies.
TABLE 27. LONG TERM AERATION EFFECT ON TKN IN FINAL EFFLUENT
Days
Aerated
0
11
20
30
BODC
•'• • 3
A
3.5
2.9
1.4
1.6
(mg/1)
B
2.6
2.0
1.4
1.8
COD (mg/1)
A
184
165
157
157
B
142
141
137
135
TOC (mg/1)
A
59
51
39
40
B
46
38
34
32
TKN (mq/1)
A
2.6
2.3
2.2
2.3
B
1.8
1.8
1.7
1.8
Sample A = 100% Final Effluent Wastewater
Sample B = 75% Final Effluent Wastewater/25% Upstream Water
It was noted that the COD/BOD5 ratio for both Samples A and B exceeded
fifty, which indicated a well biologically treated Industrial effluent. It
was doubtful whether longer aeration time would have caused significant changes.
The major problem with meeting third stage NPDES Permit requirements was
shown to be removal of Antimony and Copper (heavy metals). The Antimony re-
sulted from a dye fixative for certain add dyes needed to meet customer's
end use colorfastness requirements for certain shades. Alternate after-fixing
methods, as well as color reformulations, were suggested and placed under In-
vestigation. The Copper also resulted from meeting customer's specific end-
use colorfastness requirements for certain colors. Alternate methods of treat-
ment as well as reformulations were suggested and placed under investigation
in order to reduce the Copper content 1n the final effluent.
61
-------
The single instance of not meeting phenol requirements was thought to be
due to analytical difficulties because this parameter's requirement was met
during the remaining nineteen months of this study segment.
A particle size distribution and particle count is provided in Table 28
where secondary clarifler (biological) effluent was compared with multimedia
filter effluent (final effluent). In each instance approximately three-fourths
of the particles were 2.5 microns or smaller. It was Interesting to note that
there were approximately seventy percent fewer particles 1n the multimedia
filter effluent. These particle counts substantiate turbidity readings and
visual checks made in-plant which show a very clear, though colored, final
effluent.
The multimedia filter, with and without chemical feeds, has been demon-
strated to be a viable advanced wastewater treatment technique for biologically
treated, secondary-clarified, chlorinated wastewater from plants dyeing and
finishing fabrics knitted from man-made fibers. There is no readily apparent
reason why this technology cannot be applied to secondary wastewaters from
plants dyeing and finishing fabrics manufactured from man-made fibers or
dyeing and finishing these same yarns 1n accepted yarn and/or fabric forms.
Small amounts of one or more coagulant chemicals, which may be complemented
by powdered activated carbon addition, has been demonstrated to further reduce
organic pollutant and residual color levels 1n secondary wastewater. The
success of this technology remains tied to the quality of wastewater influent,
the nature of the wastes being treated, and responsible wastewater treatment
plant operation.
The application of the multimedia filtration technique with supplemental
chemical additions has been shown to provide a very high quality effluent which
has met very stringent NPDES Permit requirements designed to protect extremely
small streams used for navigation, fish and wildlife propagation and recrea-
tion.
The somewhat less successful color removal cannot be considered a failure
because of the nature of the colored compounds 1n the wastewater. The presence
of residual color in this particular multimedia filter effluent made 1t very
difficult to treat to a quality satisfactory for dyeing and finishing reuse.
62
-------
TABLE 28. PARTICLE SIZE DISTRIBUTION
SIZE RANGE
SAMPLE: SECONDARY
<1.25 u
1.25 - 2.5
2.5 - 5.0
5.0 - 7.5
7.5 - 12.5
12.5 - 25
>25 u
TOTAL
PERCENT
CLARIFIER EFFLUENT
29.7
54.2
7.2
3.6
1.6
2.0
1.2
99.5
APPROXIMATE
NUMBER/ML
4.60 x 106
8.40 x 106
1.12 x 106
0.56 x 106
0.25 x 106
0.31 x 106
0.19 x 106
15.5 x 106
SAMPLE: MULTIMEDIA FILTER EFFLUENT
<1.25 u
1.25 - 2.5
2.5 - 5.0
5.0 - 7.5
7.5 - 12.5
12.5 - 25
>25 u
TOTAL
23.5
50.0
21.0
2.2
--
—
96.7
1.45 x 106
2.25 x 106
0.93 x 106
0.098 x 106
--
--
4.45 x 106
SAMPLES TAKEN 6/8/76: PRESERVED WITH MERTHIOLATE
63
-------
Should very stringent color requirements be imposed, then other means of re-
moval demonstrated in the pilot water reuse study of this project would have
to be applied. The cost of doing so would be very htgh.
An expanded table showning NPDES discharge requirements has been provided
in Table 29. A three-month monitoring report has also been compared to these
NPDES requirements in Table 29.
TABLE 29. NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM
DISCHARGE MONITORING REPORT
PERMIT CONDITIONS
IN POUNDS PER DAY
POUNDS PER DAY
PARAMETERS
BOD5
Total Suspended
Solids
Total Kjeldahl
Nitrogen
Ammonia
Total Phosphorus
Total Chromium
Total Zinc
Antimony
Total Copper
Phenols
Flow (MGD*)
pH (Units*)
AVERAGE
210
417
285
46
225
4.7
21
79
6.7
9.6
5.0*
6.0-8.5*
MAXIMUM
320
689
398
92
469
8.6
41
113
9.6
75
5.5*
MINIMUM
0.0
11.2
38.8
4.8
19.1
0.71
0.97
22.4
1.45
0.89
0.000*
6.9*
AVERAGE
96.9
150.5
80.7
12.8
175.9
0.84
3.99
27.6
2.03
1.50
2.624*
MAXIMUM
195.2
329.0
180.2
33.5
283.6
1.41
7.52
38.0
3.09
2.47
3.160*
7.5*
Permit Reporting Period: June 1, 1976 through August 31, 1976.
* Units as shown - not pounds
64
-------
SECTION 7
WATER REUSE - PILOT STUDY
The second major objective of this project was to determine whether dye-
ing and finishing wastewater, which had been treated biologically and by phy-
sical/chemical means, via multimedia filtration with chemical addition, could
be further treated to a quality suitable for dyeing and finishing reuse. The
pilot study was carried out using two approaches. The first was a mobile
trailer equipped with chemical treatment to coagulate color and other pollu-
tants, settle it to remove the greater portion of the heavy chemical sludge
and filter the clarifier supernatant for greatly improved removals. The second
was a 5-column train consisting of columns charged with sand, powdered active
carbon, organic scavenging resin, cation ion-exchange resin, and anion ion-
exchange resin. Wastewater treated via this entire scheme was evaluated 1n
the laboratory to determine its suitability for reuse in the dyeing and fin-
ishing of man-made fiber fabrics. The equipment, its operation and results,
are described in the following.
THE MOBILE PILOT PLANT
The mobile pilot plant was a wastewater treatment plant consisting of a
chemical coagulation chamber, chemical addition equipment, twin flocculator
tanks, horizontal parallel tube clarifier, and mixed media filter. This unit,
hereinafter referred to as the MPP (mobile pilot plant), was used to chemical-
ly coagulate the majority of the color and other pollutants present In this
particular wastewater. The reduced color/pollutant load in the MPP effluent
was further treated to remove most of the remaining color, organics, and heavy
metals.
The MPP coagulation system consisted of an Influent line outfitted with
an adjustable flow control valve, a soleniod valve which closed the influent
65
-------
line during backwashing, and provisions for the simultaneous injection of up
to four different chemicals. Four 12-gallon chemical mixing tanks and four
chemical feed pumps were provided for these chemical additions. A 1/30 Hp
mixer was provided for mixing the chemical solutions. The coagulation system
also consisted of a rapid-mix tank which provided a rapid-mix time of one
minute at the maximum flow rate of 10 gpm by means of a 1/3 Hp mixer. The
wastewater gravity flowed into the first of two flocculator tanks. The first
flocculator was equipped with a flocculation paddle driven by a 1/12 Hp gear
motor at 6 RPM. The second flocculator was equipped with a flocculator
paddle driven by a 1/12 Hp gear motor at 2 RPM. The detention time in each
of these tanks was ten minutes at the maximum flow rate of 10 gpm. The pip-
ing to this system was such that the first flocculation compartment could be
by-passed by simply closing the valve to the first compartment and then open-
ing the valve to the second compartment which allowed the wastewater from
the rapid mix tank to flow directly into the second flocculator tank.
The clarifier flow was from the second flocculator tank only, irrespec-
tive of whether one or both had been used. This system consisted of a
settling tank with parallel, 7 1/2° from horizontal, hexagonal, one-inch
settling tubes thirty-nine inches long. Detention time was twenty-five
minutes with a tube loading rate of 1.67 gpm/sq.ft. The flow from the clar-
ifier was then filtered through a two square-foot surface area single-media
filter. The design flow rate for the filter was five gpm/sq.ft. The design
backwash rate was 17 gpm/sq.ft. with a fixed surface wash rate of two gpm/
sq.ft. The filter was set to automatically backwash at a headloss of seven
feet, but a backwash could also be initiated manually by an "initiate"
button on the control panel.
Pilot plant flow rate was controlled by the adjustable flow control
valve in the influent line and matched with a float valve above the filter.
The flow rate was indicated by a flow meter in the effluent line. The back-
wash flow rate was controlled and set by means of an adjustable flow control
valve provided in the backwash line.
The Mobile Pi lot Plant Operating Procedure
The influent to the MPP unit was the final effluent wastewater which
was diverted for further treatment instead of discharged directly to the
66
-------
receiving stream. This dyeing and finishing wastewater had been biologically
treated, secondary clarified, chlorinated and treated through the multimedia
filter plant as previously described. This water was taken from a chlorina-
tor feed water line under pump pressure ahead of the chlorinator; a tee and
solenoid valve provided a water supply under pressure without need of a
supplementary sump and/or pump. The flash mix tank was not used because of
a foaming problem which developed when high alum dosages were used. Water
and Injected chemicals were added in the first flocculator where initial
flocculatlon took place under slight agitation from the 6 RPM stlrrer. Secon-
dary flocculator effluent, after slow mixing, was gravity fed Into the horizon-
tal tube clarifier where the heavier, rapidly settling solids were removed.
The supernatant was filtered through the single media filter to remove roost
suspended matter. The single media filter was backwashed when floe carry-
over was easily visible. This usually occurred at a headloss of approximately
four feet. The backwash was initiated manually but operated by an analog con-
troller. Backwash water used was effluent from the MPP which had been stored
In a three-hundred gallon tank. Backwash rate was thirty-four gpm and control-
led with the backwash flow control valve. During each backwash* the tube clari-
fier was drained to remove sol Ids and then refilled with backwash water during
the last part of the backwash cycle. The tube clarifier was drained because It
was the only means of wasting the settled sludge and the backwash water from the
filter. Wastewater treated 1n this manner had greatly reduced amounts of color
and pollutant levels. It was then piped to the second phase of pilot treatment,
the 5-column train.
FIVE-COLUMN PILOT WATER TREATMENT PLANT
The final effluent from the MPP was given further treatment In the 5-
column train. This pilot treatment plant consisted of five pressure columns
with a decarbonator incorporated between the cation and anlon columns. Flow
through the plant was measured by a 5/8 Inch bronze meter; flow rate was
monitored by a ball check valve. Influent to this portion of the pilot plant
was provided by a 3/4 Hp deep well water pump. Dimensions of the five fiber-
glass columns were 9-5/8" I.D. x 4 feet 9-5/16 Inches high. Each column was
equipped with two 0-100 psi pressure gauges for measuring inlet and outlet
67
-------
pressure and to indicate the pressure loss across the beds. Refer to Table
30 for design parameters for this 1.5 gpm 5-column pilot water treatment
plant. Piping was arranged so that the full 1.5 gpm Influent (from the MPP)
could be directed Individually to each of the columns except the anlon ex-
changer. It was necessary for influent to the anion exchanger to first have
been treated through the cation exchanger and the decarbonator. Removal of
carbon dioxide by the decarbonator was necessary so that anlon exchanger
efficiency could be kept high. Sand and carbon columns were only backwashed
for physical removal of entrapped solids. The remaining three columns re-
quired both backwashing for physical removal and chemical regeneration. Note
that backwash flow rates were varied for each of the columns. Sand filtra-
tion was for protection against suspended solids fouling of the remaining
columns' media. No appreciable color or pollutant removals were obtained,
as this installation served only as a protection for other units. Carbon
served as an adsorption and absorption media. Its use has been well docu-
mented. The organic scavenging resin was evaluated to determine what effect
it had on color removal first and on organic pollutants second. The cation
and anion exchangers were for final polishing by removing charged color
particles, metals known to affect dyeing and finishing, and other charged
molecules which were removable.
Filter Backwash & Operations Sequence
Table 30 provides information on backwash and regeneration requirements
for all units. The sand filter was backwashed using pilot plant effluent
whenever headloss reached 8 psi or at least once per week. The carbon column
was backwashed with sand filter effluent whenever headloss reached 4 psi.
The organic trap resin was backwashed and regenerated using carbon column
effluent. The cation exchanger was backwashed and regenerated using carbon
filter effluent when effluent pH increased by 0.2 - 0.3 pH units. The anion
exchanger was backwashed and regenerated with the cation exchanger effluent.
During the upflow backwashing, resin loss was a problem which had to be con-
trolled by operator monitored backwash rate. Visual examination was made
and flow rate was controlled to prevent resin loss. The operation and back-
wash/regeneration operations of this pilot plant were extremely Involved and
time consuming. It was necessary for an operator to remain with the equipment
68
-------
TABLE 3d DESIGN DATA FOR 1.5 GPM FIVE-COLUMN PILOT WATER TREATMENT PLANT
10
EQUIPMENT
No. Units
Max. Influent
Max. Effluent
Media Type
Media Support
0.6 - 0.8 mm
Filter Sand
Volume of
Media (Cu.Ft.)
Depth of Media
(Inches)
Diameter of
Column (In.)
Height of
Column (In.)
Regeneration
or Backwash
Backwash
Rate (GPM)
SAND
FILTER
1
1.5 GPM
1.5 GPM
.45-. 50 ran
Filter Sand
4"
1.5
36"
9 5/8"
57 5/16"
Backwash
6
CARBON
FILTER
1
1.5 GPM
1.5 GPM
20 X 50 mesh
Acti vated
Carbon
4"
1.5
36"
9 5/8"
57 5/16"
Backwash
1.5
ORGANIC
TRAP
1
1.5 GPM
1.5 GPM
Dowex 11
4"
1.3
32"
9 5/8"
57 5/16"
Backwash &
Regeneration
1.0
CATION DECARBON-
EXCHANGER ATOR
1 1
1.5 GPM 1.5 GPM
1.5 GPM 1.5 GPM
Invercarb
C-110
4" None
1.3
32"
9 5/8" 12"
57 5/16" 48"
Backwash &
Regeneration
3.0
ANION
EXCHANGER
1
1 . 5 GPM
1.5 GPM
Invercarb
A-200
4"
1.3
32"
9 5/8"
57 5/16"
Backwash &
Regeneration
1.0
(Continued)
-------
TABLE 30. (Continued)
SAND
EQUIPMENT FILTER
Backwash MPP
Water Source Effluent
Regenerant
% Solution
of Regenerant
Lbs. Regenerant/
Regeneration
CARBON
FILTER
Sand
Filter
-
Nad 40%
-
ORGANIC
TRAP
Carbon
Fi 1 ter
NaCl/NaOH
NaOH 4.0%
NcCl 7.5 Ibs.
NaOH .75 Ibs.
CATION DECARBON-
EXCHANGER ATOR
Organic
Trap
HC1
30%
26 Ibs.
AN I ON
EXCHANGER
Cation
Exchanger
Soda Ash
12%
5 Ibs.
NaCl = Sodium Chloride
NaOH = Sodium Hydroxide
HC1 = Hydrochloric Acid
-------
through the entire backwash sequence. Any scale-up of this equipment should
be equipped with automatic flow controls and sufficient monitoring equipment
to insure adequate backwashing and complete chemical regeneration.
EVALUATION OF PILOT PLANT EFFLUENT WATER QUALITY
Color Removal
Color was measured as apparent color with a Hellige glass color disc and
expressed as Pt-Co units of color. Extensive color measurements were made
from influent wastewater from manufacturing through final effluent from the
pilot plant. Table 31 provides some of the extensive color measurements made
throughout the entire process.
Color removal between full scale wastewater treatment plant influent and
effluent was approximately 55%, with a residual color of approximately 200
units remaining to be removed by the pilot treatment processes,
The MPP effected various removals dependent upon the amount of alum or
alum/polymer used for coagulation. It should be noted that approximately
eighty percent of the total dye used in both plants was disperse dye; con-
sequently coagulation was demonstrated to be effective as a removal mechanism
for large amounts of color. Soluble color had to be removed by ion exchange
resins in the organic trap, cation and anlon exchangers of the pilot units.
It should be noted that through the MPP, approximately 7-20% color was re-
moved when 100 mg/1 alum was used along with varying dosages of polymeric
coagulant aid. However, when alum dosages were increased, color removal was
also increased. At 200 mg/1 alum, some 29-40% color was removed; at 250 mg/1
alum, 20-80% color was removed; and at 350 mg/1 alum, 71-62% color was re-
moved. At 350 mg/1 alum, consistently higher amounts of color were removed.
Average color removal across the 5-column wastewater treatment pilot
unit was approximately ninety percent. The sand filter removed essentially
no color, as was expected. The activated carbon filter exhibited a continuing
reduction in color removal efficiency with continuing throughput. Mid-way
through the project, color removals of 60-80 Pt-Co units could be obtained;
however, with new carbon, color removals up to 110 Pt-Co units were obtained.
Carbon in the column was replaced part-way through the project. The organic
71
-------
TABLE 31. EVALUATION OF COLOR REMOVAL FROM TEXTILE WASTEWATER
PRESENT WASTEWATER TREATMENT PROCESS
UNTREATED
MANUFACTURING
WASTE
Uni ts
Pt-Co
500
500
400
500
350
400
800
300
500
400
500
600
400
400
300
BIOLOGICALLY
TREATED WASTE
Units
Pt-Co
200
200
200
175
175
225
250
275
225
275
300
250
225
200
175
(Continued)
CHEMICAL FEED
RATES AHEAD OF
MULTIMEDIA FILTERS
s:
cc
mg/1
10
10
10
10
10
10
10
15
15
10
10
10
10
10
10
CC
LU
O
mg/1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.5
0.5
0.25
0.25
0.25
0.25
0.25
0.10
o
-------
TABLE 31. (CONTINUED)
PRESENT WASTEWATER TREATMENT PROCESS
CD
»— >
a:
0=3
LU 1—
^f ^C
LU LU LU
ce =3 H-
\— zco
•z. ^ «a:
Units
Pt-Co
400
400
400
100
500
400
500
600
300
400
500
400
500
LU
>- H-
—1 CO
1 ^^
^ 3
(J
•— O
CD LU
O t—
O LU
»— * O£
CQ h-
Units
Pt-Co
225
225
225
250
250
250
250
200
200
175
300
200
250
(Continued)
CHEMICAL FEED
RATES AHEAD OF
MULTIMEDIA FILTERS
s:
=3
i
mg/1
10
10
10
10
10
10
10
10
10
10
10
10
10
fV*
LU
s:
o
o.
mg/1
0.10
0.10
0.10
0.05
0.05
0.05
0.05
0.10
0.05
0.10
o
•*
a.
mg/1
15
15
-
25
25
25
25
25
\—
LU
_l =3
«*_!
ZLU
1— I LU
LU LU
Units
Pt-Co
200
175
200
175
200
175
200
200
150
150
200
175
200
WATER REUSE PROJECT
MPP CHEMICAL
FEED RATES
y
=>
*C
mg/1
250
250
250
250
250
100
100
100
100
170
200
250
ac.
UJ
s:
0
o.
mg/1
1
2
5
12
12
12
12
EFFLUENT FROM
LU
_l 1— t—
HH OZ
CQ — J «C
Et-H _J
0-Ou
Units
Pt-Co
130
90
80
140
100
200
175
160
125
140
120
125
160
cc.
LU
0*-
tO Lu
Units
Pt-Co
130
90
80
140
100
200
175
140
Z ££
O LU
03 h-
C*. _J
O Lu
Units
Pt-Co
70
45
30
90
40
120
125
100
CJ
>— 1
"5^
•0:0-
CD «a:
DC. a:
ot-
Units
Pt-Co
70
45
35
80
40
120
125
90
cc.
UJ
CD
Z Z
0<
t_> l.J
units
Pt-Co
50
40
10
50
30
80
70
70
cc
LU
CD
Z
3£ i^
O Z
z x
ff. LU
Units
Pt-Co
17
20
5
35
10
60
40
35
CO
-------
TABLE 31. (CONTINUED)
PRESENT WASTEWATER TREATMENT PROCESS
0
•— i
C£
0 =)
LU I—
«t «=c
LU U. LU
ce ra j—
»— z: co
=5 § 3:
Units
Pt-Co
500
400
800
500
700
400
300
400
400
400
500
450
i
LU
—1 CO
—I <
0 ~~
•_• Q
CD LU
O 1—
—I <.
O LU
•— t ce
CO >—
Units
Pt-Co
250
300
250
250
250
200
250
275
275
250
250
240
CHEMICAL FEED
RATES AHEAD OF
MULTIMEDIA FILTERS
*^r
ZD
j
«C
mg/1
10
10
10
10
10
10
10
10
10
10
10
10
oi
LU
^H
_J
o
mg/1
0.10
0.10
0.10
0.10
0.10
0.10
0.10
0.10
0.10
0.10
0.10
0.10
0
^£
Q.
mg/1
25
10
10
10
10
10
10
10
10
10
10
10
t—
LU
g^ 1
•Z. Lu
t-t U.
U. LU
Units
Pt-Co
200
200
200
250
200
175
200
250
250
225 '
200
175
WATER REUSE PROJECT
MPP CHEMICAL
FEED RATES
2E
l
-------
scavenging resin appeared to remove small amounts of color when it was first
used; however, during the latter half of the project period, almost no color
removal was obtained.
The cation and anion exchangers together removed virtually all the color
present when influent to the cation exchanger contained less than fifty Pt-Co
units of color and when large alum dosages had previously removed most dis-
persed color. Carbon is not effective in removing color due to dispersed
materials.
This complete pilot wastewater treatment plant demonstrated that residual
color could be removed from wastewater and that it could be rendered satis-
factory for dyeing and finishing re-use. The fact that soluble and insoluble
dyes must be removed by different mechanisms, when present in the same waste
stream, was demonstrated.
pH Determinations
The pH was measured with a Beckman pH meter equipped with reference
calomel and glass electrodes. The meter was standardized daily with pH 4.0
and pH 9.0 buffers. Wastewater Influent to the pilot plant had a pH of 7.0 -
7.5. In the first treatment stage when up to 350 mg/1 alum was used in the
MPP, the pH was reduced by approximately 1.0 unit. No appreciable pH change
occurred during passage through sand, carbon and organic scavenging resin
filters. Effluent from the cation exchanger had a pH of 2.4 to 3.1, because
of hydrogen ion exchange for metals and other multlvalent substances. How-
ever, pH was increased to between 4,1 and 8.8 during passage through the
anion exchanger where hydroxide was exchanged for other anlonlc groups. In
a scale-up for a large plant, both add and alkaline neutralization feeds
would be required in order to insure uniform pH water to processing. See
Table 32 for representative pH at all parts of the total wastewater system.
Turbidity
Turbidity was measured with a Hach Model 2100A Turb1d1meter for all
pilot plant readings. Turbidity was usually noticeably higher 1n the MPP
effluent than the influent, because of fine alum floe carryover. This floe
carryover, not removed by clarification and media filtration, was Increas-
ingly visible toward the end of the operating cycle. Turbidity removed by
75
-------
TABLE 32. pH EVALUATION
PRESENT WASTEWATER TREATMENT PROCESS
UNTREATED
MANUFACTURING
WASTE
Units
7.3
7.2
7.2
7.3
7.1
7.1
7.1
6.6
7.1
7.6
7.5
7.4
7.6
8.8
BIOLOGICALLY
TREATED WASTE
Units
7.1
7.4
7.1
7.2
7.0
7.1
7.1
7.2
7.3
7.3
7.2
7.3
7.5
7.3
(Continued)
CHEMICAL FEED
RATES AHEAD OF
MULTIMEDIA FILTERS
§
mg/1
10
10
10
10
10
10
10
15
15
10
10
10
10
10
POLYMER
mg/1
0.10
0.10
0.10
0.10
0.10
0.10
0.10
0.5
0.5
0.25
0.25
0.25
0.25
0.25
o
o_
mg/1
35
35
35
35
35
35
35
35
35
35
35
35
35
35
FINAL
EFFLUENT
1
Units
7.2
7.5
7.3
7.3
7.1
7.2
7.3
7.4
7.4
7.1
7.2
7.0
7.5
7.3
WATER REUSE PROJECT
MPP CHEMICAL
FEED RATES
5
mg/1
250
250
250
250
250
250
250
250
250
250
250
250
250
250
POLYMER
mg/1
EFFLUENT FROM
dSz
3Q _J
Units
6.5
6.4
6.5
6.4
6.8
6.5
6.4
6.8
6.7
6.7
6.6
6.6
6.5
t— i
<£ a.
CD <3T
o: ad
01—
Units
6.4
6.6
6.6
6.5
6.9
6.7
6.4
6.4
6.7
6.7
6.7
6.6
6.5
CATION
EXCHANGER
Units
2.6
2.7
2.7
2.8
2.6
3.1
2.7
2.8
2.9
2.9
2.9
2.9
2.8
AMI ON
EXCHANGER
Units
8.7
8.4
8.1
8.8
6.2
7.3
6.7
6.1
5.8
4.8
4.6
4.6
4.5
-------
TABLE 32. (CONTINUED)
PRESENT WASTEWATER TREATMENT PROCESS
UNTREATED
'MANUFACTURING
WASTE
Units
7.7
7.8
7.4
7.7
6.9
7.4
7.4
7.8
7.5
7.4
8.0
9.2
7.3
8.3
BIOLOGICALLY
TREATED WASTE
Units
7.4
7.6
7.5
7.3
7.1
7.1
7.2
7.3
7.2
7.2
7.1
7.2
7.2
7.2
(Continued)
CHEMICAL FEED
RATES AHEAD OF
MULTIMEDIA FILTERS
s:
mg/1
10
10
10
10
10
10
10
10
10
10
10
10
10
10
POLYMER
mg/1
0.10
0.10
0.10
0.10
0.05
0.05
0.05
0.05
0.10
0.05
0.10
o
o.
mg/1
35
15
15
25
25
25
25
25
»—
LU
I-H LI-
LULU
Units
7.3
7.5
7.5
7.4
7.3
7.3
7.4
7.5
7.4
7.3
7.2
7.0
7.4
7.3
WATER REUSE PROJECT
MPP CHEMICAL
FEED RATES
z;
U-
Units
6.6
7.0
6.7
6.7
6.4
6.3
7.1
6.9
6.8
6.6
z on
O LU
IS
CJ tL-
Units
6.7
7.0
6.8
6.7
6.5
6.4
6.7
6.7
6.8
6.5
U>
-------
TABLE 32. (CONTINUED)
PRESENT WASTEVIATER TREATMENT PROCESS
z
i— i
o:
0=3
LU •—
H- CJ
LU ' ' LU
a: :=>•—
»— Z CO
z<«t
=> S 3
Units
7.3
7.4
7.1
7.5
9.2
7.4
8.5
7.5
9.3
8.5
7.5
10.3
LU
5- I—
_J CO
^ 2
% Q
C3 LU
O 1-
-J <
O LU
*— • Orf
CO h-
Units
7.1
7.2
7.2
7.2
7.3
7.3
7.2
7.4
7.4
7.3
7.4
7.3
CHEMICAL FEED
RATES AHEAD OF
MULTIMEDIA FILTERS
J^
=D
— 1
mg/1
10
10
10
10
10
10
10
10
10
10
10
10
Q,
LU
2£
^»
_1
O
O.
mg/1
0.10
0.10
0.10
0.10
0.10
0.10
0.10
0.10
0.10
0.10
0.10
0.10
CJ
<£
a.
mg/1
25
10
10
10
10
10
10
10
10
10
10
10
1—
LU
_l =>
^f 1
ZU_
1— I LU
LU LU
Uni ts
7.3
7.4
7.4
7.3
7.4
7.1
7.3
7.5
7.1
7.3
7.4
7.5
WATER REUSE PROJECT
MPP CHEMICAL
FEED RATES
js^
"~%
^ i
«x
mg/1
250
250
250
150
200
200
250
250
350
350
350
350
Q,
LU
^»
—I
O
a.
mg/1
12
12
12
3
3
3
3
3
3
3
3
3
EFFLUENT FROM
LU
l-H OZ
ca — i
-------
sand, carbon and organic scavenging columns was only slight; the organic
scavenging resin lost much of its turbidity removal ability during the latter
half of the project.
The most significant turbidity removals were effected by the cation ex-
changer. It is not known whether the removal was by physical or chemical
means. As more color was removed from the wastewater, the interference due
to turbidimeter light beam absorption was reduced giving a more accurate
reading. See Table 33 for turdibity readings throughout the entire full-
scale and pilot wastewater treatment facilities.
Specific Conductivity
All specific conductivity measurements were made with a Beckman Conduc-
tivity Bridge. Since addition of salt in dyeing with direct dye colors was
not common practice in these two manufacturing plants, the normal final
effluent conductivity was 450 - 600 mhos with occasional readings slightly
above and below this range. Conductivity increased to 600 - 800 mhos in the
MPP trailer effluent due to alum treatment. This range was generally con-
stant through sand, carbon and organic resin filter columns. However, con-
ductivity increased to a typical 1500 - 3000 mhos when passing through the
cation exchanger; this was due to increased hydrogen ion concentration.
Table 34 reflects specific conductivity readings through the full-scale and
pilot treatment plants. The abrupt reduction in specific conductivity of
anion exchanger effluent should be noted. This indicated a high purity water
was generated.
Specific conductivity was an excellent indicator of breakthrough of both
the cation and anion exchangers and was employed as an operational tool.
Unusually high readings in anion exchanger effluent, shown in Table 33, was
the signal that caused this unit to be backwashed/regenerated.
Total Solids (TS)
Total solids were determined gravimetrically, using TOO milliliter
samples. The treated wastewater effluent to the receiving stream contained
approximately 500 mg/1 of total solids; this water source became the influent
to the pilot plant. Passage through the MPP unit generally netted a slightly
79
-------
TABLE 33. TURBIDITY
PRESENT WASTEWATER TREATMENT PROCESS
UNTREATED
MANUFACTURING
WASTE
FTU
71
78
60
77
79
95
60
77
66
73
67
65
61
88
BIOLOGICALLY
TREATED WASTE
FTU
29
28
20
21
18
16
29
20
29
40
24
17
10
15
(Continued)
CHEMICAL FEED
RATES AHEAD OF
MULTIMEDIA FILTERS
z:
mg/1
10
10
10
10
10
10
10
15
15
10
10
10
10
10
POLYMER
mg/1
0.10
0.10
0.10
0.10
0.10
0.10
0.10
0.5
0.5
0.25
0.25
0.25
0.25
0.25
o
a.
mg/1
35
35
35
35
35
35
35
35
35
35
35
35
35
35
FINAL
EFFLUENT
FTU
5.3
3.8
3.5
4.7
4.4
4.1
7.9
8.0
9.9
15.0
8.1
2.5
2.5
2.4
WATER REUSE PROJECT
MPP CHEMICAL
FEED RATES
2:
mg/1
250
250
250
250
250
250
250
250
250
250
250
250
250
250
POLYMER
mg/1
EFFLUENT FROM
LU
^S£
CO — 1
-------
TABLE 33. (CONTINUED)
PRESENT WASTEWATER TREATMENT PROCESS
UNTREATED
MANUFACTURING
WASTE
FTU
88
56
65
66
23
60
55
64
58
88
63
59
58
55
BIOLOGICALLY |
TREATED WASTE
FTU
8
14
14
15
21
17
18
16
22
22
19
30
18
19
(Continued)
CHEMICAL FEED
RATES AHEAD OF
MULTIMEDIA FILTERS
z:
mg/1
10
10
10
10
10
10
10
10
10
10
10
10
10
10
POLYMER
mg/1
0.10
0.10
0.10
0.10
0.05
0.05
0.05
0.05
0.10
0.05
0.10
0
o.
mg/1
35
15
15
25
25
25
25
25
FINAL
EFFLUENT
FTU
2.5
6.0
6.0
6.3
5.4
5.9
7.7
5.4
5.8
3.4
2.6
4.5
4.2
4.0
WATER REUSE PROJECT
MPP CHEMICAL
FEED RATES
_i
mg/1
250
250
250
250
250
250
-
100
100
100
100
170
200
250
POLYMER
mg/1
1
2
5
12
12
12
12
EFFLUENT FROM
LU
d££
CO _1<£
z: CL a.
FTU
5.4
8.8
8.1
4.7
12.0
6.1
5.3
9.4
8.8
8.0
5.4
5.4
or
LU
01—
CO LU
FTU
3.9
7.0
6.2
4.6
12.0
7.0
5.1
9.4
8.4
6.6
"Z.
-------
TABLE 33. (CONTINUED)
PRESENT WASTEWATER TREATMENT PROCESS
i— <
O =3
H- O
111!1 LiJ
rv ~~^ i -
IDS 31
FTU
51
60
100
69
15
44
55
44
24
52
47
30
LU
>• t—
-i O
O 1 —
O UJ
J^S
03 »-
FTU
21
33
32
25
22
15
7
21
31
30
20
17
CHEMICAL FEED
RATES AHEAD OF
MULTIMEDIA FILTERS
y*
3
•*
mg/1
10
10
10
10
10
10
10
10
10
10
10
10
cr:
UJ
^_
I
o
0-
mg/1
0.10
0.10
0.10
0.10
0.10
0.10
0.10
0.10
0.10
0.10
0.10
0.10
- o
<
a.
mg/1
25
10
10
10
10
10
10
10
10
10
10
10
z:
LU
1 13
^C I
z u.
»-t LU
Lt_ LU
FTU
4.5
4,6
4.2
7.0
4.0
2.3
2.2
5.0
9.0
11.0
17.0
5.5
WATER REUSE PROJECT
MPP CHEMICAL
FEED RATES
"SL
^_^
-------
TABLE 34. SPECIFIC CONDUCTIVITY
oo
OJ
PRESENT WASTEWATER
TREATMENT PROCESS
CHEMICAL FEED
RATES AHEAD OF
MULTIMEDIA FILTERS
i
rv
UJ
jgr
3
s: o
1 ^£
o
3: j o- a.
mg/1
10
10
10
10
10
10
10
15
15
10
10
10
10
10
mg/1 mg/1
0.10
0.10
0.10
0.10
0.10
0.10
0.10
0.5
0.5
0.25
0.25
0.25
0.25
0.25
(Continued)
35
35
35
35
35
35
35
35
35
35
35
35
35
35
I
H-
UJ
__l ~*^
^C — J
•Z. U.
«-• U.
Lu UJ
umhos
610
510
540
560
480
460
WATER
MPP CHEMICAL
FEED RATES
1 .i _
1
i
1 C£
! I UJ
*y
< *"">
i
et
mg/1
250
250
250
250
250
250
250
250
250
250
250
250
250
250
LU
S _!»—(—
1-1 OZ
_l CO _I«C
o
o.
mg/1
'
O •— ' -J
s: a- a.
umhos
640
635
610
605
490
480
680
800
760
780
780
700
700
680
REUSE PROJECT
EFFLUENT FROM
> j
; a: : z ce.
, LU ' O UJ
. OH- , ca J—
, Z _J . DC _J
I/) U- ' <_} U-
(j
i— t
CL
^^
a: a:
O 1—
££
UJ
3Z ^
f} i^^
i—* rc
1— 0
O UJ
umhos ; umhos umhos | umhos
630 , 640 690
630 ; 630 630
i 615 ; 615
615
605 i 630 640
i 490 i 500
475 : 480
685 ', 685
i
i
770 ! 780
i
790 | 780
760 j 760
700 | 700
710 j 710
680 1 690
i
I
j
515
480
680
820
800
780
710
720
700
2300
1600
1600
1400
1400
510
1800
3000
2700
2200
2200
2100
2100
2000
a;
LU
2;
"^ ^f
OX
I-H O
Z X
CC LU
umhos
19
16
16
84
14
220
44
12
10
15
36
27
30
100
-------
TABLE 34. (CONTINUED)
CX)
PRESENT NASTEWATER 1! •..•TO pcncr pomFfT
-REATMENT PROCESS !; "n ~* Rc°SE PRUJEC'
CHEMICAL FEED ' '• ppp nFv^ft'
RATES AHEAD OF ! .! FEED '^s" '
y'JL'IXEDIA FILTERS ! :
1 ' '
' i ' ' ' ' ' }
: ! . '1 i !
-' QJ ; z ! • a:
: .1 i i i ! I ' t < i Q£
s: ^ . ° 5: _i 2; >• ^ozoi—
O i— i u. l O O ~^ — ;<•— <
< a. 'a. u_--jj cc : — 2: G. Q. • to u.
: ; i
rc/1 ma/1 ma/1 umhos mg/1 TIC/! urchos 'umhos
"*!"*'"' ' i "
10 ; 0.10 ! 35 250 I 710 710
; • ; ; •
10 0.10 i 15 ; 250 690 690
10 i 0.10 15 590 250 710 710
; •
10 : 0.10 ; 540 ! 250 650 660
!
10 0.10 ' 10 590 250 630 670
:
10 i 0.10 10 430 250 620 630
1
10 ; 540 550
i
10 I 0.05 630 100 : 1 700 690
10 = 0.05 ! 100 j 2 610 : 610
! 1 • '
10 ; 0.05 25 . 100 5 580
t i
10 i 0.05 ! 25 550 ,100 12 540 ;
10 | 0.10 i 25 170 12 ; 750 i 760
10 1 0.05 ! 25 200 | 12 '• 520 |
i 1 '
10 '' 0.10 i 25 250 ! 12 590
; 1 i
10 i 0.10 | 25 520 250 12 j 750 | 740
(Continued) j ; 1 •
iFFLUEN
1
!
O LU 1
CQ 1— '.
CC. _J
<: —i
00.
umhos i
710 ;
670
710
680 ;
670
620
1
510
700
610
730
i
j 740
i
T FROM
*
!
o :
z i
<: a. •
O ef.
C£. C£
O t— :
umhos ;
700 ;
670 i
720 !
770
720
640
550
740
630
700
730
r^ \
\ j j ,
ol i
i— i ~r" ,
h- tJ
UJ
umhos
i
1800
1
1700
1900
4500
2300
1900
1500
2200
1500
1450
1600
^^
.
3
z <
O —
*— ^_^
Z X
-------
TABLE 34. (CONTINUED)
C3
CJ1
PRESENT WASTEWATER
TREATMENT °ROCESS
CHEMICAL FEED !
RATES AHEAD CF
MULTIMEDIA FILTERS
2C
^^
'•
«=c
mg/1
10
10
10
10
10
10
10
10
10
10
10
I
1
.
; QC
LiJ
; 2:
} ^—
—I
• 0
' C.
f
: mg/1
i
10.10
1
0.10
0.10
0.10
0.10
0.10
0.10
0.10
0.10
010
0.10
I
| 4
i
cj i :
^X -
^t p^ L
, »~^ *
WATER
REUSE PROJECT
MPP CHEMICAL
FEED RATES
z
• *
^
_• 2:
•J— ^3
.1^ ' j
Q. j 1_U i_J i
10 ;
10
. 10 55(
10 ; 35(
10
1 200
i 200
3 250
3 250
j| 350
10 j 400 1 350
10 j
10 42C
i
350
) 350
t
H1
il
!l
i
! t
t
j i
i
ce. •
: <_U uj
, S — 1 1— 1—
>• >•— • O Z
—1 'CQ _l <
: O O •— i _J
Q,
2; Q. 0.
|
\ mg/1 umhos
j i
12
12
750
780
3 590
3 630
3 620
3
3
3
3
3
3
650
650
650
640
630
650
i
i
I or
I UJ
1 *"^ K*~
j Z —1
; (/) U.
i
'umhos
|750
j 790
I 600
1 640
• 630..
J660
i640
650
640
650
650
EFFL'JENT FROM
|
i
j z a:
OLJ
CD 1—
C£. _l
^^ >^H
' t_> U-
1
i umhos
i
j 745
\ 810
600
640
650
660
640
650
640
650
650
' ce
' ' LU
" ' Z Z
• z i o «c
1 UJ
i
• umhos umhos
i
750 1800
| 810
2200
620 1700
i i
660
650
680
660
1850
1500
1600
1400
630 1300
700
670
650
2600
2100
1800
o:
UJ
O
Z
-------
lower total solids concentration. Only a very minor reduction in total solids
was realized through the combined treating of sand, carbon and organic scaveng-
ing filters; however, by the time treated wastewaters exited the anion exchang-
er, the last step in the pilot process, 85% of the total solids had been re-
moved. Table 35 presents the total solids at various locations within the
Total treatment system. When 350 mg/1 alum was used in the MPP, the total
solids levels in the pilot plant effluent were less than 50 mg/1, which in-
dicated that a very high quality water had been generated.
Biochemical Oxygen Demand (BOD,-)
BOD5 determinations were made using the standard 5-day incubation t1r«e
and the procedure found in the fourteenth edition of Standard Methods For The
Examination of Water 8 Wastewater. Dissolved oxygen was determined by a
properly standardized dissolved oxygen meter. All samples were seeded with
5% secondary clarifier effluent (non-chlorinated). Table 36 is provided to
show 5-day values for all major locations in the full-scale and pilot treat-
ment processes. BODr values were too low to be particularly meaningful;
therefore, BODg, COD and TOC values have been compared in Table 39. BODg in
the influent to the pilot plant averaged 5.1 mg/1 and was reduced almost
sixty percent by the MPP unit alone; only about ten percent more reduction was
realized through the 5-column train.
ll cal Oxygen Demand (COD)
Chemical oxygen demand was determined by the dichromate reflux method
found in the fourteenth edition of Standard Methods For The Examination of
Hater & Wastewater. Less than half the total COD removal occurred 1n the MPP
unit, with most occurring during treatment through the 5-column train. In
Table 37 COD values throughout the whole wastewater treatment process have
been shown.
Total Organic Carbon (TOC)
A Beckman Model 215 Carbon Analyzer was used for all TOC determinations.
Acidified samples were Nitrogen sparged to remove carbonates and bi carbonates.
Twenty microliter samples were used for analysis. Organic carbon was con-
verted to carbon dioxide by reaction with pure oxygen at 950°C. ; the newly
converted carbon dioxide was measured and recorded. Total organic carbon was
86
-------
TABLE 35. TOTAL SOLIDS (mg/1)
CD
I
PRESENT >,ASTE>JA-ER "EATXENT PROCESS ij *A,ER RE.SE PROJECT
i CHtMiCAi. ."
"£C3 ^ -t
; >- , RATES AnEAD G~ :' '"-'---"^Vl"-"" E~,ri.^E'i~
,_ .' — , v, . „-,,--...,, _-,__-. i"Ci> XM.C.J
^ ' <^ i lUi_ i ii'iCUin fiuiCKj ;
— : '_5 I/1) '
o:
; . -^
*~~ r_^
< < .^
Si E5 t^
t1"
3
*/l j
'
725
780
340
745
850
425
680
o s :
o :
o -»- • — •
co <: ; . s ; 51
o 2 ; _j o
CVJ r~ j ^C • CL.
ing/"i j mg/1 ; ~,g/ .
! 10 0.10
i
590 10 ! 0.10
i
10
t
0.10
565 10 0.10
10
10
0.10
0.10
1
10
510 10
610
535
495
(Continued)
10
10
10
10
10
10
10
0.10
0.50
0.50
0.25
0.25
0.25
0.25
0.25
0.10
— • ,
* 7Z • ' C£ '—
0 '_= '• ~ - ~
< _ < . . ^ >- •— o ^r < —
; — H i : ^j o 5 — _. . S a:
O« j tX- t-i-l ! ^C ^- •£— — *. . -. ' "~
,-ng/". ; ~g/~, ., r,-,g/", r.g/", r;/~. ,-g/". !
35 ! 250 500 390
' i
35 ! 500 ; 250 i 488
• - i i
35 :
35 520
; 250
I
250 459
35 ; 250 \ 428 , 346
35 j j 250 : 545 420 ;
f '
35 250 : 578 458
35 i 495 250 '
35
35 550
35 1 490
j
35 465
35
35
35
250 :
i ; ,
250
250 i 474 362
i
250 i 480 384
250 453 376
250 i ; 451 363
250 i 453 392
: i
~
t-_
O
z:
o re
rr x
^C L^J
,g/-,
34
33
125
26
230
88
75
37
38
82
44
-------
TABLE 35. (CONTINUED)
o>
03
PRESENT *ASTE/;ATER TREA
CHEMICAL F
7KEM PROCESS '-ATER
Htul :
» • — — - —»•-*••
RcoSE PROJEC.
>• RATES AHEAD OF ; "i:.:-":,1-^- £.-
'-
— =
~~" —^
•^C <
— - — _-f
"^ *~ — '.
— — • r/*
5 < < :
-;/-. ;
i
600
670
625 •
710
685
545
680
^^ _-_^ ^7O . i
^- _*_ , O '•
»-i- ^*-
x. z: ^: x
O i — < "-1-!
r.g/-, : r.g/-.
416 50
410 ' 47
448 76
411 , 68
!
330 ; 45
451 80
453 '. 90
i
387 \ 39
i
392 50
378 48
i
-------
TABLE 35. (CONTINUED)
PRESENT XASTEwATER
WATER REoSE PROJEC
RATES A.-.EA5 GF
iXuLTIiXEDIA FILTERS
FEED RATES
00
10
< <
5: ID —
•z. < <
^ ^- 3
^
860
'_> t/',
O uj
QQ
-------
TABLE 36. BODs (mg/1)
PRESENT WASTEWATER TREATMENT PROCESS
UNTREATED
MANUFACTURING
WASTE
mg/1
375
385
315
260
350
355
312
415
290
325
330
350
312
185
325
330
300
335
75
145
222
198
265
BIOLOGICAL
SYSTEM
EFFLUENT
mg/1
11.0
13.7
13.5
12.3
12.0
14.2
5.8
23.7
29.7
19.0
4.9
7.1
8.4
10.0
7.6
8.6
10.0
9.2
11.0
18.0
(Continued)
CHEMICAL FEED
RATES AHEAD OF
MULTIMEDIA FILTERS
. s:
mg/1
10
10
10
10
10
10
10
15
15
10
10
10
10
10
10
TO
10
10
10
10
10
10
10
POLYMER
mg/1
0.10
0.10
0.10
0.10
0.10
0.10
0.10
0.50
0.50
0.25
0.25
0.25
0.25
0.25
0.10
0.10
0.10
0.10
0.05
0.05
0
Q.
mg/1
35
35
35
35
35
35
35
35
35
35
35
35
35
35
35
15
15
FINAL
EFFLUENT
mg/1
4.9
3.8
3.9
5.6
5.3
5.4
5.1
7.5
13.5
12.5
8.0
3.6
3.2
2.8
3.5
5.2
4.9
8.7
4.8
4.2
4.4
5.7
5.5
WATER REUSE PROJECT
MPP CHEMICAL
FEED RATES
2:
_i
mg/1
250
250
250
250
250
250
250
250
250
250
250
250
250
250
250
250
250
250
260
250
0
100
100
POLYMER
mg/1
0
1
2
EFFLUENT
UJ
-J h-H-
HH OZ
00 _J «t
O •-« — 1
2: o. o.
mg/1
2.4
1.8
1.7
1.8
2.6
1.9
2.4
4.7
1.8
1.4
1.5
1.4
1.8
1.5
1.9
2.1
2.7
2.5
5.2
ANION
EXCHANGER
mg/1
1.7
1.5
1.3
1.4
2.0
1.0
1.4
4.5
1.7
1.2
1.4
2.2
2.1
2.1
2.2
3.0
3.7
2.9
2.4
2.8
90
-------
TABLE 36. (CONTINUED)
PRESENT WASTEWATER TREATMENT PROCESS
z
1— «
o =>
UJ h-
H~ * .*
^C ^£
uj u» uj
on rs i—
>— Z t/>
z 3 lJ-
, , ^_ j^_
00 OO UJ
mg/1
9.3
10.3
11.8
15.3
10.7
12.3
6.0
5.8
8.5
7.0
8.3
4.3
7.0
7.0
CHEMICAL FEED
RATES AHEAD OF
MULTIMEDIA FILTERS
•C"
^J
1
«£
mg/1
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
rV
UJ
^F*
*^ -
|
o
Q-
mg/1
0.05
0.05
0.10
0.05
0.10
0.10
0.10
0.10
0.10
0.10
0.10
0.10
0.10
0.10
0.10
0.10
0.10
o
0*f
CL.
mg/1
25
25
25
25
25
25
10
10
10
10
10
10
10
10
10
10
10
i—
UJ
—I Z3
z u.
<—• U.
U. UJ
mg/1
2.7
2.1
4.5
5.1
5.1
5.3
4.1
3.7
3.1
2.8
3.1
5.1
4.3
6.4
4.5
WATER REUSE PROJECT
MPP CHEMICAL
FEED RATES
S;
3
«c
mg/1
100
100
170
200
250
250
250
250
150
200
200
250
250
350
350
350
350
Of.
«EZ
^__
i
o.
mg/1
5
12
12
12
12
12
12
12
3
3
3
3
3
3
3
3
3
EFFLUENT
UJ
•«J H* h™
I-H O 2Z
03 -»<
O +-* — J
Z O_ O_
mg/1
2.4
1.8
1.9
2.4
3.4
1.9
1.6
1.1
2.6
1.3
2.8
2.5
1.0
3.7
1.2
1.2
0.9
LU
C9
Z?
^^ ^C
oa:
<-> t_>
z x
-------
TABLE 37. COD (mg/1)
PRESENT WASTEWATER TREATMENT PROCESS
UNTREATED
MANUFACTURING
WASTE
mg/1
500
1098
960
BIOLOGICAL
SYSTEM
EFFLUENT
mg/1
321
288
278
242
232
(Continued)
CHEMICAL FEED
RATES AHEAD OF
MULTIMEDIA FILTERS
s:
<
mg/1
10
10
10
10
10
10
10
15
15
10
10
10
10
10
10
10
10
10
10
10
10
10
10
POLYMER
mg/1
0.10
0.10
0.10
0.10
0.10
0.10
0.10
0.5
0.5
0.25
0.25
0.25
0.25
0.25
0.10
0.10
0.10
0.10
0.05
0.05
o
-------
TABLE 37. (CONTINUED)
PRESENT WASTEWATER TREATMENT PROCESS
CO
•— i
a:
O =3
1— O
LU U. LU
OC Z3 1—
§1§
mg/l
960
995
845
887
_j
0 J—
co z: LU
O LU :=}
— 1 1— — J
O 00 U-
i— i >- U_
CQ CO LU
mg/l
249
CHEMICAL FEED
RATES AHEAD OF
MULTIMEDIA FILTERS
. s:
_i
mg/l
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
Q,
UJ
£
1
0
Q.
mg/l
0.05
0.10
0.05
0.10
0.10
0.10
0.10
0.1Q
0.10
0.10
0.10
0.10
0.10
0.10
0.10
0.10
0.10
o
^f
CL.
mg/1
25
25
25
25
25
25
10
10
10
10
10
10
10
10
10
10
10
t—
LU
_J =3
*f, —i
z: LU
U_ LU
mg/l
170
155
152
WATER REUSE PROJECT
MPP CHEMICAL
FEED RATES
z:
=3
_i
mg/l
100
100
170
200
250
250
250
250
150
200
200
250
250
350
350
350
350
Q,
1 if
^S^
^M
^f
o
Q_
mg/l
5
12
12
12
12
12
12
12
3
3
3
3
3
3
3
3
3
EFFLUENT
UJ
— • r™ r™
^™^ ^J 2»
BQ — J ^t
s: a! 5^
mg/l
154.
130.
104.
128.
98.4
118.
103.
173.
81.3
76.9
84.0
ce
LU
0
z?
z <
o 3:
t~H CJ
Z X
mg/l
34.4
34.4
11.6
32.0
7.9
19.0
4.0
7.5
7.4
<4.0
<4.0
93
-------
TABLE 38. TOTAL ORGANIC CARBON
PRESENT WASTEWATER TREATMENT PROCESS
CHFMICAL FEED RATES AHEAD
OF MULTIMEDIA FILTERS
ALUM
mg/1
POLYMER
mg/1
P A C
mg/1
FINAL
EFFLUENT
mg/1
WATER REUSE PROJECT
MPP CHEMICAL
FEED RATES
ALUM
mg/1
POLYMER
mg/1
EFFLUENT
MOBILE
PILOT
PLANT
AN I ON
EXCHANGER
mg/1
TOTAL ORGANIC CARBON
15
10
10
10
10
10
10
10
10
10
10
10
0.50
0.25
0.10
0.10
0.10
-
0.10
0.10
0.10
0.10
0.10
0.10
35
35
35
15
-
-
25
10
10
10
10
10
100
67
60
66
61
64
140
62
56
62
28
74
250
250
250
250
250
250
250
150
250
250
350
350
_
-
-
-
-
-
3
3
3
3
3
3
56
-
59
42
36
30
74
60
36
31
26
28
50
4
4
10
6
5
10
12
4
<1
2
2
94
-------
calculated by proportioning peak level of sample to peak level of a known
standard. Only about fifteen percent TOC was removed by the MPP unit while
seventy-five percent of the remaining TOC was removed by the 5-column train.
See Table 38 for comparison.
The BODg, COD and TOC values and removal efficiencies have been compared
in Table 39 for the pilot treatment plant.
TABLE 39. POLLUTANT REMOVALS VIA PILOT PLANT
Total
Pollutant
Parameter
BOD5
COD
TOC
Influent
5.14
185
61
MPP Unit
Effluent
2.13
105
51
5-Column Train
Removed
59
43
16
Effluent
1.92
11
13
Removed
10
90
75
Removed
mg/1
3.22
174
48
%
63
94
79
While most BOD5 removal was accomplished in the MPP unit, the 5-column
train was needed to remove most of the COD and TOC present. The ratios of
COD to BOD5 and TOC to BODg increase noticeably between initial influent and
final effluent values.
The Nitrogen Group - Ammonia, Nitrates, Total Kjeldahl Nitrogen (TKN)
Considerable data was accumulated on the Nitrogen group made up of am-
monia, nitrates, and TKN, because of concerns over these parameters in present
and future permits to discharge wastewater to streams.
The nitrate analysis was performed according to procedures in the 1974
edition of EPA's manual of Methods for Chemical Analysis of Water & Wastes.
The brucine method was used. An intense yellow color resulted from the re-
action of nitrate and brucine after a reaction time of twenty-five minutes
at 100°C. this yellow color was measured spectrophotometrlcally at 410 nm
wavelength.
Both ammonia and TKN were determined according to procedures 1n the
fourteenth edition of Standard Methods For The Examination of Water & Waste-
water. Ammonia was determined by adjusting pH to 9.5, distilling 1t into
95
-------
boric acid, titrating with 0.02 N sulfuric acid and calculating the Nitrogen
present as ammonia. The TKN was determined by converting the organic Nitro-
gen to a Mercury ammonium complex. This complex was decomposed by sodium
thiosulfate and the ammonia distilled from an alkaline medium and absorbed
in boric acid. Titration was by 0.02 N sulfuric acid and thus was calculat-
ed.
The determined ammonia, nitrate and TKN values have been recorded in
Table 40. Ammonia levels were usually less than 0.3 mg/1 when final effluent
wastewater was received as influent to the pilot treatment plant. Therefore,
it was not possible to evaluate the effectiveness of ammonia removal via the
steps in this pilot plant. A small amount of nitrates were present in the
pilot plant influent, at usually less than one mg/1 concentration. Very
little nitrate was used in the dyeing and finishing plants and this par-
ticular wastewater was considered nitrogen deficient, so that nitrate
(as NaNO-j) was added prior to biological treatment to insure adequate nu-
trient levels for biological conversion. Some nitrate was removed through
the MPP unit, with almost all the remaining removed through the 5-Column
train.
Most of the Nitrogen in the pilot plant influent was 1n the form of
organic Nitrogen or TKN. Because the ammonia was usually below the accu-
rate detection limits the organic Nitrogen level was considered to be the
TKN level. Addition of alum with and without polymeric coagulant aids,
ahead of the MPP reactor/clarifler provided some TKN removal. This re-
moval was approximately thirty percent on the average. The 5-Column unit
further reduced TKN levels by an additional seventy-four percent to approx-
imately 0.5 mg/1.
A major problem at this location, referred to earlier, was final ef-
fluent TKN concentration versus NPDES permit requirements for the final
six months of the current permit period. This pilot study underscored a
basic premise that the TKN remaining 1n the final effluent to the stream,
as currently treated, would be extremely difficult to remove technically
and that removal would be economically prohibitive. Further, the TKN
remaining in the MPP unit effluent was sufficiently high that 1t would not
96
-------
TABLE 40 NITROGEN SERIES
PRESENT WASTEWATER TREATMENT PROCESS
CHEMICAL FEED RATES AHEAD
OF MULTIMEDIA FILTERS
ALUM
mg/1
POLYMER
mg/1
P A C
mg/1
FINAL
EFFLUENT
mg/1
WATER REUSE PROJECT
MPP CHEMICAL
FEED RATES
ALUM
mg/1
POLYMER
mg/1
EFFLUENT
MOBILE
PILOT
PLANT
AN I ON
EXCHANGER
mg/1
15
10
10
10
10
10
10
10
AMMONIA.
10
15
10
10
10
10
10
10
10
10
0.50
0.25
0.10
0.10
-
0.10
0.10
0.10
NHROGEN
0.10
0.50
0.25
0.10
0.10
-
0.10
0.10
0.10
0.10
35
35
35
15
-
10
10
10
35
35
35
35
15
-
10
10
10
10
0.2
0.2
0.2
0.3
1.6
<0.1
0.4
<0.1
<0.3
<2.0
<0.3
<0.3
<0.3
<0.3
<0.05
0.3
0.4
<0.3
250
250
250
250
250
250
350
350
250
250
250
250
250
250
250
250
350
350
-
-
-
-
-
3
3
3
-
-
-
-
-
-
3
3
3
3
0.2
0.3
0.4
<0.1
-
0.4
0.2
0.2
<0.3
<2.0
<0.3
0.45
<0.3
<0.3
<0.3
<0.3
<0.3
<0.3
<0.1
<0.1
<0.1
<0.1
<0.3
<0.1
<0.1
<0.1
<0.3
<2.0
<0.3
<0.3
<0.3
<0.3
<0.3
<0.3
<0.3
<0.3
(Continued)
97
-------
TABLE 40. (CONTINUED)
PRESENT WASTEWATER TREATMENT PROCESS
CHKM1CAL FEED RAILS AHEAD
OF MULTIMEDIA FILTERS
ALUM
mg/1
POLYMER
ing/1
P A C
ing /I
FINAL
EFFLUENT
mg/1
WATER REUSE PROJECT
MPP CHEMICAL
FEED RATES
ALUM
mg/1
POLYMER
mg/1
EFFLUENT
MOBILE
PILOT
PLANT
AN I ON
EXCHANGER
mg/1
TOTAL KJELDAHL NITROGEN
15
10
10
10
10
10
10
10
10
10
10
0.50
0.25
0.10
0.10
-
0.10
0.10
0.10
0.10
0.10
0.10
35
35
35
15
-
25
10
10
10
10
10
<2.0
2.2
1.7
2.8
2.4
4.2
3.6
2.2
2.6
3.1
5.0
250
250
250
250
250
'250
150
250
250
350
350
-
-
-
-
-
-
3
3
3
3
3
<2.0
1.2
2.0
1.7
4.2
2.3
2.1
2.2
2.1
1.4
1.2
<2.0
0.3
<0.3
0.3
0.3
<0.3
0.4
0.4
0.8
0.3
0.5
98
-------
be possible to meet NPDES requirements of eighty-three pounds per day final
effluent TKN level, should total flow be increased significantly. The
volume of sludge which would be generated with a coagulation process would
be completely disproportionate to the small amount of TKN which would also
be removed, i.e. the cost for the incremental removal would not be justified.
Total Phosphorus
Total Phosphorus was determined by the Ascorbic Acid method following
Persulfate digestion as prescribed in the procedures found 1n the 1974
edition of EPA's manual of Methods for Chemical Analysis of Water & Wastes.
This parameter was monitored because of tremendous Interest in phosphorus
levels in North Carolina streams as a result of phosphate mining and fertil-
izer plants within the state. Total Phosphorus levels generally present no
problem; however, on some days levels are unusually high (8 mg/1 or more).
The MPP unit removed significant amounts of Phosphorus; indications were
that the greater the alum dosage, the lower the effluent concentration as
shown in Table 41. Approximately two-thirds of the total Phosphorus was
removed via the MPP unit and almost all of the remaining one-third was re-
moved via the 5-Column train.
Chlorides
Chlorides were determined according to the mercuric nitrate method given
in the fourteenth edition of Standard Methods For the Examination of Water
& Wastewater.'
Influent to the pilot plant contained low chloride levels (20-70 mg/1).
As shown in Table 41, no consistent or significant change occurred 1n the
MPP unit. However, the 5-Column train, largely the anlon exchanger, removed
chlorides to below 10 mg/1 concentration. Such a low level would offer no
problems to water reuse in dyeing and finishing.
Sulfates
The sulfate analysis was according to the turbldimetric method given
in the fourteenth edition of Standard Methods For the Examination of Hater
& Wastewater.
99
-------
TABLE 41. PHOSPHORUS, CHLORIDES, SULFATE
PRESENT WASTEWATER TREATMENT PROCESS
CHEMICAL FEED RATES AHEAD
OF MULTIMEDIA FILTERS
ALUM
mg/1
POLYMER
mg/1
P A C
mg/1
FINAL
EFFLUENT
mg/1
WATER REUSE PROJECT
MPP CHEMICAL
FEED RATES
ALUM
mg/1
POLYMER
mg/1
EFFLUENT
MOBILE
PILOT
PLANT
AN I ON
EXCHANGER
mg/1
TOTAL PHOSPHORUS
15
10
10
10
10
10
10
10
10
10
10
CHLORIDES
15
10
10
10
SUL FATES
15
10
10
10
10
0.50
0.25
0.10
0.10
-
0.10
0.10
0.10
0.10
0.10
0.10
0.50
0.25
0.10
0.10
0.50
0.25
0.10
0.10
0.10
35
35
35
15
-
25
10
10
10
10
10
35
35
35
15
35
35
35
15
10
4.9
7.9
6.2
7.4
8.6
8.7
12.1
7.7
7.0
9.9
5.8
69
19
50
25
2
<5
23
<5
33
250
250
250
250
250
250
150
250
250
350
350
250
250
250
250
250
250
250
250
350
-
-
-
-
-
-
3
3
3
3
3
-
-
-
-
-
-
-
-
3
1.1
1.0
5.7
1.4
1.1
1.3
5.2
3.3
1.3
3.9
0.4
•
73
49
49
1.9
84
73
36
66
160
0.10
<0.10
0.06
0.30
0.11
<0.10
<0.10
0.10
<0.10
<0.10
<0.10
2
2.5
4.0
3.2
<5
1
<5
<5
<5
100
-------
Sulfate levels 1n process treated wastewater varied greatly from approx-
imately two to thirty mg/1 which resulted from variations 1n sulfate contain-
ing chemicals useage in dyeing and finishing. Sulfate concentration was in-
consequential in this wastewater, which became the influent to the pilot
plant, because the sulfate level was significantly increased in the MPP unit
by the alum (aluminum sulfate) additions. As shown in Table 41, the 5-
column train effectively removed the sulfates to below five mg/1. The higher
the alum dosage needed in the MPP unit for removal of any one of several
specific parameters, the greater the sulfate level which would be removed in
the anion exchanger. The efficiency of the anlon exchanger would be greatly
reduced if high alum dosages became necessary 1n a full-scale plant modeled
after this pilot treatment plant.
Metals
Metals were analyzed by atomic absorption procedures. Table 42 provides
information on metals analyses for multimedia filter effluent. MPP effluent
and anion exchanger effluent for the metals Aluminum, Antimony, Calcium,
Copper, Chromium, Iron, Magnesium, Manganese and Zinc.
Only trace amounts of Chromium and Manganese were found 1n the multi-
media filter effluent, so no meaningful evaluation of their removal could be
made. It was considered likely that the pilot plant would effect removals
of virtually any amounts of these found 1n dyeing and finishing wastewaters.
Aluminum concentration was noticeably increased by alum dosages in the
MPP unit; however, the final effluent from the pilot plant showed less than
0.5 mg/1.
Increases in concentrations of Iron and Zinc following treatment through
the MPP unit were determined to be from tramp metals in the alum source used.
The 5-column train effectively removed these multlvalent metals from waste-
water. This was important because of known metal-dye complexes which cause
dye shade changes on fabrics; such would likely preclude reuse of any waters
containing significant amounts (greater than 0.5 mg/1) of Chromium, Copper,
Iron, Manganese, Magnesium and Z1nc.
The presence of significant amounts of these metals in any wastewater
being considered for reuse would have to be taken Into account when evaluating
101
-------
TABLE 42. METAL SERIES
a:
ID
_J
mg/1
METAL
10
10
10
10
10
10
10
10
10
10
10
10
10
METAL
250
250
250
250
250
100
170
150
200
350
350
350
a.
mg/1
DC
UJ
—1
O
a.
mg/1
ANALYSES ON
35
35
35
35
15
-
10
-
25
25
10
10
10
0.10
0.50
0.25
0.10
0.10
0.10
0.10
0.05
0.05
0.10
0.10
0.10
0.10
ANALYSES ON
-
-
-
-
-
12
12
3
3
3
3
3
-
-
-
-
-
-
-
-
-
-
-
_
i
§. ALUMINUM
— j
O =)
s: •-<
•-« o
I— —1
«S o
ug/1 mg/1
c
^CHROMIUM
a:
UJ
-------
TABLE 42. (CONTINUED)
s:
ID
_J
^£
mg/1
o
•a:
a.
mg/1
QC
UJ
O
(X
mg/1
s:
z:
3C
13
^c
ug/1
1
I-H
f-
^t
ug/1
z:
1—4
<_ )
mg/1
s:
o
oc.
ug/1
o:
LU
a.
a.
o
o
ug/1
1
H^
ug/l
lAGNESIUM
i.
mg/i
UJ
CO
UJ
1
3E.
uq/l
tj
•z.
»— t
t*4
ug/1
METAL ANALYSES ON ANION EXCHANGER EFFLUENT
800 1200 0.02 < 30 <20 < 30 .090 < 30 < 30
100 < 500 0.08 < 30 <20 50 .015 < 30 < 30
100 < 500 0.14 < 30 <20 210 .016 < 30 < 30
200 < 500 0.16 < 30 <20 < 30 .012 <30 < 30
1400 < 500 0.14 < 30 <20 470 .016<30 < 30
103
-------
various treatment methods to render waters suitable for critical manufactur-
ing operations.
OPERATIONAL PROBLEMS OF THE PILOT PLANT
A number of problems were encountered with the pilot plant and its
operation during the approximately eleven months of operation. The MPP unit
was operated from December 1975 through November 1976 while the 5-column
train was operated from late February 1976 through November 1976.
The initial problem was one of frozen pipes in the MPP unit during the
severe late December to early February cold. This problem was solved by keep-
ing water flowing through on a continuous basis. Operation as a reactor/clarl-
fier was carried out only during the warmer part of the day and on several ex-
tremely cold days the unit could not be operated. The 5-column train was pro-
tected somewhat by shelter and was operated without damage from freezing.
Variable chemical feed pumps in the MPP unit gave tremendous reliability
problems. The solution was finally to calibrate them for a fixed feed rate
and vary the chemical feed concentration in the stock solution to give the
desired chemical dosages.
Two operational problems were encountered with the MPP unit. A foaming
problem occurred in the rapid mix tank when 100 mg/1 or more alum was used.
This foaming problem was likely aggravated by residual surface active materials
in the wastewater. The solution to this problem was to stop the rapid mixer
and depend on the slow mixer in the first flocculator tank for providing the
level of contact needed between alum and the suspended waste particles. The
second, more important problem was the very short runs when alum dosages were
250 - 350 mg/1. Very large quantities of settleable alum floe was generated
which quickly overloaded the settling tubes 1n the tube clarifler and back-
washing was then required after only two hours operation. This problem would
be overcome in a full-scale coagulator by provisions for intermittent and/or
continuous sludge wasting.
The 5-column train was operated with fewer mechanical equipment problems.
The major problem was adjusting the regenerant feed rates during backwashlng/
regeneration by use of an aspirator and valve system which was very difficult
104
-------
to adjust. This problem would not be encountered 1n a full scale model of
this pilot plant because the aspirators would be replaced by metering pumps.
Two other operational problems were encountered with the 5-column train.
Resin losses from organic scavenging, cation exchanger, and am'on exchanger
columns during backwash regeneration was a problem which was tied to the
above mentioned problem of controlling flow during this step. The second
problem was the need for an operator to be in attendance at all times during
the complete regeneration cycle - a cycle which took some seven and one-half
hours when all five columns had to be regenerated. This regeneration time
often had to be spread over two days which greatly reduced effective equip-
ment run time.
Backwash/regeneration time and gallons through-put for each of the pilot
plant component parts has been shown below for normal operation. These time
requirements were often much longer when equipment problems occurred.
Normal Gallons Through-Put or Backwash and/or
Pilot Plant Before Backwash (BW) and/or Regeneration
Component Regeneration (Reg) Time Required
MPP Trailer 4200 BW 1/2 Hour
Sand Filter 1/wk BW 1/2 Hour
Carbon Filter 1/wk BW 1/2 Hour
Organic Trap as anionic column (BW + Reg.) 2 Hours
Cation Exchanger 1200 BW + Reg. 2 Hours
Anion Exchanger 1900 BW + Reg. 2-1/2 Hours
The other limiting factor to pilot plant operation was the quality of the
influent wastewater. If the biological plant gave problems, these problems
had to be corrected before any pilot plant runs could be made, due to man-
power availability. No pilot runs were made when the influent had unusually
high turbidity (70-100 JTU) which normally followed a biological plant upset.
After a manufacturing plant shutdown of two days or longer, one or more days
usually passed before initiating further pilot plant runs due to abnormally
high amounts of fine suspended matter in the multimedia filter effluent.
The major effects of these problems was an extension of the time required
to complete the project and a reduction of the number of experiments possible
to run. 105
-------
SECTION 8
LABORATORY REUSE EVALUATIONS
Laboratory investigations were conducted to determine if residual color
in the multimedia filter effluent would be scavenged by fibers during conven-
tional dyeing operations. If the residual color were not scavenged, 1t would
be theoretically possible to find a dyeing procedure to reuse a portion of the
wastewater without considerable further treatment. This would make treatment
for dyeing and finishing reuse more attractive economically.
LABORATORY DYE SCAVENGING EVALUATION
Laboratory experiments were carried out in the plant dye laboratory.
Greige knitted fabric (tricot) was used for ease of handling. The various test
fabrics were made from (a) type 6 caprolactam nylon, dull luster; (b) secondary
cellulose acetate, dull luster; (c) knitted fabric blend of 80% cellulose
triacetate, dull luster, and 2Q% type 6 caprolactam nylon, dull luster; and
(d) homopolymer polyester, dimethylterephthalate type, semi-dull luster. It
should be stated that the 80% triacetate/20% nylon tricot construction was
used for evaluating triacetate. The tricot knitted construction sufficiently
hides the nylon so that the discoloration noted is contributed by the triace-
tate and not by the nylon. For the purposes of this experiment, this fabric
was considered as representative of triacetate fiber.
In this investigation, dyeings using three different sources of water were
made on each fabric as follows:
1. Laboratory water, ground water cation exchange treated for production use.
Pt-Co color less than two units, (this was the control for the experimen-
tation.)
2. Wastewater after full-scale multimedia filtration at the wastewater treat-
ment plant (not the pilot installation). Pt-Co color - 400 units.
106
-------
3. Wastewater blended with cation exchange treated water for processing
fabric in the manufacturing plant's dyeing and finishing operation, A
blend of 100 ml. wastewater with 900 ml. of laboratory water. Pt-Co
Color - 40 Units.
The four fabrics were also scoured in the three sources of water identifi-
ed above. No optical brightener was added. Scouring of 20-gram swatches of
fabric were made in a steam-heated water bath in one-liter stainless steel
beakers. A 50:1 liquor to goods (weight) ratio was a standard laboratory
procedure.
Three 20-gram swatches of each of the four grelge fabrics were prepared.
Four stainless steel beakers were then filled with each of the three types of
water to be used, making a total of twelve. Then each beaker was charged with
the following chemicals: (a) one gram per liter of a proprietary solvent scour
(60% aromatic and aliphatic solvent blend/40% anlonic and nonlonlc surfactant
blend), (b) one gram per liter of sodium trlpolyphosphate. The fabric swatches
were impaled on sharp stainless steel rods colled over beaker positions on the
steam-heated water bath where the scours were to be made. A motor driven
attachment stirs the swatches by a reciprocating up/down motion 1n the beaker.
The water and chemical charged beakers were placed on the water bath and
the swatches were lowered into the beakers via stainless steel rods, which were
attached to the reciprocating stirring mechanism. Stirring was begun at once
as the temperature was raised to 716C (160°F) and maintained at that temper-
ature for twenty minutes. After that length of time, an additional chemical
charge of 0.2 grams per liter of citric acid was added to each beaker and the
scouring was continued uninterrupted for an additional ten minutes. At the
end of this thirty-minute total scouring cycle, the swatches were raised via
the rods from the beakers. The change of pH during scouring was to allow color
scavenging to take place under both alkaline and add conditions. Alkaline
and acid conditions are both common in production dyeing processes.
After this scouring cycle, each swatch was removed from the retainer coll
and rinsed by hand under tap water (cation exchange treated) for thirty
seconds. Swatches were then centrifugally extracted in a laboratory ten-pound
107
-------
model extractor to remove excessive water (approximately 20% moisture by weight
of fiber remaining). Swatches were then drawn taut onto pin frames and dried
in a forced draft laboratory oven for 75 seconds at 190°C (375°F). The three
scoured swatches of each fabric were dried simultaneously to minimize any
color variation from the drying step. After drying, swatches were removed
from the pin frames and allowed to come to thermal equilibrium under ambient
laboratory conditions. Swatches were examined visually after they had been
brought to equilibrium. The observations are presented in Table 43 to show
how those scoured in 100% treated wastewater and 10% treated wastewater/90%
cation ion-exchange treated water compared to the control scoured in the
cation ion-exchange treated laboratory water.
TABLE 43. VISUAL COMPARISON OF COLOR SCAVENGING BY VARIOUS FIBERS SCOURED IN
WASTEWATER (Secondary Clarified, Chlorinated, Multimedia Filterf)
Fiber
Type 6
Caprolac-
tam Nylon
Secondary
Acetate
80/20%
Triacetate/
nylon
Polyester
(disperse
dyeable)
100 ml Treated Water/
900 ml Cation ion Ex-
change Treated Water
Pt-Co Units = 40
Very noticeable
Discoloration
Very slight dis-
coloration
Very noticeable
Discoloration
Very slight
Discoloration
100% Treated Wastewater
Position Pt-Co Units = 400 Position
4 Very Severe 4
Discoloration
2 Noticeable 2
Discoloration
Severe
Discoloration
1 Slight
Discoloration
'l = least amount of staining; 4 = greatest amount of staining
This series of experiments shows that the various fibers scavenge color
from tertiary treated wastewater in differing amounts. Type 6 nylon scavenged
the most color, even more than triacetate; these two fibers scavenge several
108
-------
times more color than either secondary acetate or polyester. A dyeing and
finishing plant processing nylon and/or triacetate could not use even the ten
percent blend of tertiary-treated wastewater with ninety percent of its reg-
o o
ular process water for scouring at temperatures up to 71 C (160 F) when treat-
ed wastewater color was 400 Pt-Co units or higher. A plant dyeing and finish-
ing only acetate and/or polyester could consider this 10/90 blend where scour-
o o
ing would be carried out at a temperature of 71 C (160 F) or less. However*
unless the plant was using extremely large amounts of water for scouring below
o o
71 C (160 F) there would be no economic justification for considering such a
blend of waters.
This series of experiments indicated that neither scouring nor dyeing
with this 10/90 blend of water could be considered in a plant dyeing and
finishing nylon and/or triacetate because of their severe residual color
scavenging effect. These two fibers comprised about 50 percent of the fabrics
which are dyed and finished at this location. In order to make the color
scavenging effect of fibers in fabric form more objective, whiteness was de-
termined for the two samples scoured in (a) 100% treated wastewater, and
(b) 10% treated wastewater, compared to a control scoured in cation exchange
treated water used for in-plant processing. Whiteness was determined on these
scoured, untinted, non-optically brightened fibers in fabric form by use of
American Association of Textile Chemists & Colorists Test Method 110-1975,
"Reflectance, Blue and Whiteness of Bleached Fabric." The formula for white-
ness found in paragraph 3.3 of this Test Method was used; it 1s: W=4B-3G where
W = Whiteness; B = Blue reflectance; and G = Green reflectance. See Table 44
for a presentation of the numerical values. The reflectance values for Blue
and Green filter readings were used to calculate whiteness. The Instrument
used to determine reflectance using blue and green filters was a Gardner
multi-purpose refleetometer.
109
-------
TABLE 44. INSTRUMENT WHITENESS COMPARISON, CONTROL
VERSUS WASTEWATER SCOURED FIBERS IN FABRIC FORM
100 ML Treated Water/
900 ML Cation 100% Treated
FIBER CONTROL Exchange Treated Water Uastewater
Type 6
Caprolactam 71 64 45
Nyl on
Secondary Acetate 68 66 60
80/20% Tri-Acetate/ 64 61 48
Nylon
Polyester (Dis- 68 67 64
perse Dyeable)
These whiteness readings confirmed the visual evaluation shown in Table 43.
Even if residual color remaining in the tertiary-treated wastewater was only
40 Pt-Co units, this water would be unsuitable for processing nylon and triace-
tate. The processing of secondary acetate and of disperse dyeable homopolymer
polyester should be considered only if further residual color reduction was
accomplished by some means such as improved removal of color or even dilution
to further reduce total residual color. The seriousness of even considering
this approach must be underscored because (a) a dyeing and finishing plant
would necessarily be handicapped by being able to process only certain fibers
and (b) the scavenging effect of other fibers, natural, animal and man-made is
unknown and would require further extensive investigation. This experiment
further strengthened the need for a water reuse evaluation. It was well es-
tablished that color removal from wastewater was difficult and was made even
more difficult by small amounts of residual color contributed by several clas-
ses of both water-soluble and water-insoluble dye types.
RESULTS OF COMPARATIVE DYEINGS USING MOBILE PILOT PLANT (MPP) EFFLUENT
Relative whiteness was used as a measure of the effect of these efforts
to obtain water sufficiently higher in quality and lower in color which could
110
-------
be satisfactorily reused in the dyeing and finishing of man-made ftber fabrics.
Water taken from several pilot plant runs was used to dye whites on nylon and
polyester; these two fibers were selected because nylon was demonstrated to be
an effective scavenger of color bodies from this particular treated waste-
water, and polyester was demonstrated as being the least affected by very
large amounts of color in the dyebath water.
Table 45 shows the relative whiteness of nylon and polyester fabrics dyed
using MPP effluent from selected pilot plant runs over the duration of the
pilot wastewater reuse study. There were several apparent discrepancies when
comparing relative whiteness of the swatches dyed using control process water
versus recycled water from the pilot plant effluent, Samples E and F tn
Table 45 indicate essentially the same whiteness on the control dyeing and on
recycled water dyeing. Note however, that the color of the pilot plant
effluent used for dyeing these two samples was high. Compare nylon Samples E
and F with sample H; when sample H was dyed using pilot plant effluent hav-
ing 35 Pt-Co units of color, it showed a significant difference 1n relative
whiteness compared to the control dyeing made at the same time. While samples
E and F were not affected by high amounts of residual color in the pilot plant
effluent used for dyeing (20 and 40 Pt-Co units respectively); sample H, when
dyed in pilot plant effluent containing 35 Pt-Co units of color, showed a
marked reduction in relative whiteness, 63 versus 69 for the control, which
indicated the fiber scavenged color from the pilot plant effluent. The most
logical explanation is that the color bodies in the pilot-treated wastewater
for samples E and F had no affinity for the nylon fiber while those color
bodies present at the time sample H was dyed did have affinity for the nylon
fiber. This should be understood 1n view of the number and complexity of
different dyes used in the manufacturing plants and the potential for chemical
change which could cause the above apparent difference in residual color
scavenging.
The nylon samples J and K showed definite color scavenging effects when
dyed in pilot plant effluent containing only two to three Pt-Co units of color.
The only explanation given was that certain add dyes were not removed by the
pilot treatment scheme and those were sufficiently neutral dyes to be exhaust-
ed onto nylon at pH 6. Dyeing results on nylon at less than two Pt-Co units
111
-------
TABLE 45. RELATIVE WHITENESS OF DYED FIBERS (FABRIC FORM)
ro
Sample
A
B
C
D
E
F
G
H
J
K
L
M
N
P
Recycled
Water
Fabric Pt-Co Units
Fiber Color
Nylon 6 125*
Nylon 6
Polyester 1
Polyester
Nylon 6
Nylon 6
Nylon 6
Nylon 6
Nylon 6
Polyester
Nylon
Polyester
Whiteness determined by Reflectance
Method 11 0-1 975.
25*
25*
25*
20
40
8
35
2
3
2
3
<2
<2
using American
*Wastewater Treatment Plant effluent recycled only
and not through 5-column train.
Water
Recycle
Date
1/14/76
1/15/76
1/14/76
1/15/76
4/7/76
5/5/76
5/26/76
6/2/76
3/8/76
3/10/76
3/8/76
3/10/76
11/8/76
11/8/76
Association
through MPP
Relative Whiteness
Control Recycled Water
79
74
77
74
68
73
67
69
76
76
74
74
63
63
69
63
73
74
69
74
65
63
71
72
74
74
63
63
of Textile Chemist & Colorfst Test
Coagul ation/Settl i ng/Fi
Itration Unit
Control dyeings were all made from regular in-plant process water; water source was deep well; prior
treatment was through cation exchange resin systems followed by decarbonizing.
-------
of color, however, were equal in quality to the results of the control dyeing.
When color was reduced below two Pt-Co units, water was satisfactory for dye-
ing all fibers in whites and very light pastel shades, as well as in a full
range of normal shades.
Figure 6 shows the color comparison made spectrophotometrically for waste-
water treated on November 8, 1976. Effluent from the full-scale wastewater
treatment plant including biological treatment, chlorination and multimedia
filtration with pre-filtration additions of 10 mg/1 alum, 0.10 mg/1 anionic
polymer and 10 mg/1 powdered activated carbon has been shown as "influent to
MPP". This influent to the MPP had 200 Pt-Co units of color. This wastewater
was treated in the MPP coagulation/settling/filtration unit with 350 mg/1
alum, and 3 mg/1 anionic polymer; effluent from this part of the pilot unit
shown on the graph was also found to have 45 Pt-Co units of color or a reduc-
tion of 77.5% color. Further treatment through the 5-Column train gave a
very clear, essentially colorless effluent, which has been shown on the top
of the graph in Figure 6 and which was found to have less than two Pt-Co
units of color. Shown in Figure 7 for comparative purposes, 1s a pilot plant
run made on 9/16/76 and compared to laboratory tap water (plant process water).
Note that the pilot plant effluent was essentially equally as color free as
the tap water control.
The series of pilot plant runs made during November, 1976 using secon-
dary clarified, chlorinated wastewater having 175-250 Pt-Co units of color
as influent, gave a pilot plant effluent essentially color free; all four
runs were measured as having a maximum of two Pt-Co units of color. However,
extremely heavy chemical feeds ahead of the reactor/clarlfier were used to
achieve that color level, 350 mg/1 alum and 3 mg/1 anionic polymer. In
addition, these four runs were through the entire 5-Column train Including
sand filtration, organic scavenging, granular activated carbon, cation and
anion exchange resins. The required high concentration of chemical feeds
created very high capital and operating costs as well as the need for sophis-
ticated wastewater treatment in the scale-up to a one million gallon-per-day
plant, presented in Section 9.
113
-------
100
O
JS 90
O
Anion Exchanger'Effluent
-------
The results of dyeing polyester indicated the greater likelihood of suc-
cess in treating wastewater treatment plant effluent to a reduced level of
color and other parameters which would allow it to be successfully reused for
scouring and possibly for dyeing in the manufacturing plant. However, several
factors must be taken into consideration. The lower the process water temper-
ature, the greater the likelihood of success with reuse of treated wastewater.
Certain processes such as scouring at temperatures below the boil and scours
at high pH's would be more easily adaptable. Extreme care would be required,
however, when considering high temperature (110-130 C or 230-265 F) dye-
ing of polyester with this type of advanced treated wastewater. Some dyes,
particularly Anthraquinone Red dispersed dyes, are extremely sensitive to
certain metal ions such as Copper, Manganese and Iron. Those individuals
responsible for dyeing must know the potential metals levels 1n process water.
These metal ions may be contributed by dyes and/or chemicals used in process-
ing or even from other sources if several water streams are fed into the waste-
water treatment plant.
Table 45 shows that dyeings on samples A and B on nylon, and C and D on
polyester, were made using water produced during two early runs of the MPP
coagulation/settling/filtration unit when color was 125 and 25 Pt-Co color
units, respectively. The nylon scavenged color efficiently as expected;
whiteness compared to the control dyeing showed about as much color scavenged
by the nylon at 25 Pt-Co units of color as when 125 Pt-Co units of color was
in the effluent from that unit. This suggests that the amount of color pre-
sent may well be secondary to what dyes or other chromophoric compounds con-
stitute the color. Polyester scavenged no color in sample D when the pilot
plant water contained only 25 Pt-Co units of color. However, when effluent
color was Increased to 125 Pt-Co units, a noticeable lessening of whiteness
was recorded which indicated that some color had indeed been scavenged by the
polyester.
It was significant that the amount of color for the two runs, through only
the MPP unit, was only slightly different in the Influent, but drastically.dif-
ferent in the effluent. This is attributed to more water soluble dyes present
in the first run which were not coagulated and removed. The pilot plant run
on 1/14/76 (See Table 46) was made without alum. Color reduction 1n the MPP
115
-------
pilot coagulation/sett!ing/filtration unit apparently resulted from physical
removal only because no chemicals were usecj. However, the pilot plant run
made the following day was made with greater than 250 mg/1 alum as the primary
coagulant. This obviously had a very significant effect in that color was re-
duced by eighty-four percent. The fact that the average Pt-Co units of color
varied from 400 units on one day to 300 units on the following day should be
noted. Despite these differences, full scale wastewater treatment plant ef-
fluent for both these two days were measured at 150 Pt-Co units of color. The
most logical explanation is that the mixture of dyes contributing to this color
were different on these two days. These two experiments, shown in Table 46,
of by-passing the 5-column train in the pilot plant were considered sufficient
to confirm that advanced wastewater treatment beyond chemical coagulation,
settling and filtration would be required to produce a pilot plant effluent
capable of being used in dyeing all fibers satisfactorily.
TABLE 46. COLOR REMOVAL - COAGULATION/SETTLING/FILTRATION
. .... - _,— , ., ,. — . - ... . - -
Full Scale Wastewater Treatment Plant
Date
1/14/76
1/15/76
Influent
400
300
Biologically Treated
Plus
Chlorination
200
175
Multimedia
Filter Final
Effluent
150
150
Pilot Plant
MPP Unit
Influent
150
150
Only
Effluent
125
25
LABORATORY TEST DYEINGS
A large number of one-liter laboratory dyeings were made on nylon,
acetate, triacetate and polyester substrates, using many of the dyes listed
for that substrate in Table 47. In order to obtain satisfactory dyeings 1n
a full range of shades including white and pastel shades, particularly on
nylon and triacetate fibers, it was necessary to provide an essentially color-
less treated wastewater for dyeing. A higher color level could be tolerated
when dyeing polyester; however, care should be taken to keep this level of color
116
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TABLE 47. LABORATORY DYE/FIBER TEST COMBINATIONS
Fibers
1. Nylon 66, Antistatic Additive
2. Nylon 6
3. Secondary Acetate
4. Triacetate
*Secondary Acetate Only
5. Polyester (Dacron T/56,
T/92 Blend)
6. Nylon T/66 (Automotive)
Dyestuffs
1. Fluorescent brighteners 191 & 59
2. Disperse Blue 3
3. Disperse Yellow 3
4. Disperse Red 91
5. Nylanthrene Blue GLF
6. Nylanthrene Yellow WGL
7. Nylanthrene Red ACD
8. Acid Blue 78
9. Acid Red 99
10. Acid Red 4
11. Acid Yellow 7
12. Direct Blue 86
13. Acid Red 52
14. Acid Red 289
1. Fluorescent Brightener 135 and
Leucophor SF
2. Disperse Blue 27
3. Disperse Blue 7
4. Disperse Red 91
5. Disperse Yellow 86
6. Disperse Red 117
7. Disperse Yellow 42
8. Disperse Blue 87
9. Disperse Yellow 82
*10. Basic Red 15
*11. Basic Blue 3
1. Fluorescent Brightener 135
2. Disperse Blue 56
3. Disperse Blue 87
4. Disperse Yellow 64
5. Eastman Poly Yellow 76T
6. Disperse Red 60
7. Disperse Red 4
8. Basic Blue 71
9. Basic Yellow 54
10. Basic Red 29
1. Acid Black 131
2. Acid Black 132
3. Acid Orange 80
4. Acid Yellow 129
5. Acid Red 213
6. Acid Red 263
7. Acid Green 40
8. Acid Blue 62
117
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low, preferably below 20 Pt-Co units. The treated water should also have a
very low metal ion content, preferably less than 0.1 mg/1 of any single metal.
Laboratory dyeings were made on 20-gram swatches of fabric in a total
liquor of one-liter for a 50:1 liquor to fabric weight ratio. Preliminary dye-
ings were made using effluent from the pilot plant to determine whether water
quality was sufficiently good to consider larger scale dyeings. The dyes and
chemicals used were obtained from manufacturing plant stock and solutions were
prepared according to standard dye laboratory practices in accordance with man-
ufacturer's and/or seller's recommendations. Laboratory tap water, taken from
processing water used in dyeing and finishing in the manufacturing plant, was
used for all chemical and dye stock solution preparations.
These 20-gram swatch dyeings, both control and exploratory, were all made
o o
on a dye laboratory steam table at approximatly (99 C) 210 F for one hour,
unless otherwise specified. This time included the approximately ten minutes
required for the bath to reach the desired process temperature. Swatches were
rinsed in laboratory tap water after dyeing.
Chemicals used were selected to be compatible with the type of dye and
fiber/fabric to be dyed. Dispersed dyes were applied to acetate fiber/fabric
with the use of 0.25 grams per liter of the sodium salt of ethylenediaminete-
traacetic acid (EDTA) sequesterant, 0.2 grams oer liter of a blended anlonic/
nonionic scouring/dyeing assistant, and 1.0 gram per liter of monosodium
phosphate to aid in scouring, without adversely affecting exhaustion or any
color property.
Disperse dyes were applied to nylon using 0.25 grams per liter of EDTA,
0.2 grams per liter of a blended anionic/nonionic, scouring/dyeing assistant
and 1.0 gram per liter of sodium tripolyphosphate to aid in scouring and to
improve levelling (uniform uptake by the fabric) of the dye.
Neutral dyeing acid dyes were applied to nylon using 0.25 grams per liter
of an anionic dyeing assistant, with affinity for the fiber under acid condi-
tions, 0.20 grams per liter of a very slightly cationic dyeing assistant with
some affinity for the anionic acid dye (this weak bond would be broken by time
and increasing temperature to allow the dye to attach Itself chemically to
118
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cationic dye sites on the fiber); 1.0 gram per liter of monosodium phosphate
which gave a pH of approximately 6-6.5 to promote exhaustion of the dye at
o o
approximately 99 C (210 F). No sequestering agent was used in making these
dyeings because any slight amount of hardness contributed by dye or chemical
would have a positive effect on dye exhaustion and the dyes used exhibited no
extreme metal sensitivity. Experience has shown that the amount of metal ions
normally present in the dyeing bath at this location has no serious effect on
the shade of the dyeing.
Basic dyes, often referred to as cationic dyes because they are positively
charged, were applied in a strongly acid dyebath at pH 3.0 - 3.5, 99 C (210 F)
for one hour. This dyebath also contained three grams per liter of a dye
carrier specific for exhaustion of this cationic dye onto copolymer polyester,
while reducing the tendency to stain homopolymer polyester. In addition, six
grams per liter of sodium sulfate (Glauber's salt) was added to prevent degrada-
tion of the copolymer polyester in this particular fabric blend. Basic dyes
O
were applied to acetate at pH 5 using one gram per liter of carrier at 99 C
(210 F) for one hour.
Premetallized dyes were applied to nylon using 0.4 grams per liter of an
anionic levelling agent, 0.02 grams per liter of copper sulfate, at pH 5-5.5
(using citric add for pH adjustment). Dyeing was carried out for 1.5 hours
at 99 C (210 F). In dyeing with premetalUzed dyes, a sequestering agent was
not used. An excess of sequestering agent could break down the dye to metal
bond and destroy the high lightfastness of this group of dyes.
Optical brighteners were applied to all fibers using one gram per liter of
monosodium phosphate plus 0.2 grams per liter of nonlonlc surfactant for one
hour at 99°C (210°F).
Triacetate used in these dyeings was part of a tricot fabric blend of 80%
triacetate/20% nylon. The nylon was so placed 1n the construction that 1t was
essentially hidden and had no significant effect on the final dyed shade. Dye-
0 O
ings were carried out at 99 C (210 F) on the laboratory steam table using a
dyebath containing three grams per liter of a commercially available carrier
(butyl benzoate is the active carrier Ingredient), 0.2 grams per liter of an
119
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anionic/nonionic blended surfactant/dyeing assistant at pH 4-4.5 (pH adjusted
with citric acid).
Dyeings were made on polyester in a closed pressurized container, holding
0.5 liters of dyebath so that the liquor to fabric weight ratio was 25:1 instead
of 50:1 as in other small laboratory dyeings. One-hour dyeings were done at
o o o o
110 C (230 F); however, at a 3 C/minute (5 F/minute) rate of temperature rise
and rate of cooling, the time of actual dyeing was slightly longer than one
hour. The dyebaths contained three grams per liter of perchloroethylene car-
rier, 0.3 grams per liter of a fatty ester lubricating agent and 0.25 grams per
liter of sequesterant, at pH 4.5-5 (pH adjusted with citric acid).
Confirmatory dyeings were made using a laboratory-size pressure beam dye-
ing machine. Approximately 400 grams of fabric (sixteen inches wide) was
wrapped onto a perforated stainless steel cylinder and Inserted in the labora-
tory dye machine. Approximately eight liters of manufacturing process water
per dyeing for control dyeings and water from the pilot plant effluent for
evaluation dyeings were used to fill the machine. Water was pumped into one
end of the perforated cylinder, through the perforations, and out through the
fabric wrapping; flow was always in one direction, from the inside to the out-
side. The dyebath was charged with dyes and chemicals prepared as described
previously for the small laboratory swatch dyeings. The rate of temperature
o o
rise was approximately 3 C per minute (5 F per minute) and was raised by steam
heat exchange through tubes located in the bottom of the beam dye machine.
o o
Rate of cooling was approximately 7 C (13 F) per minute because cooling was
carried out by overflow cooling the dyebath by the slow addition of manufactur-
ing process water.
o o
The dyeing temperature was 99 C (210 F) for nylon, acetate and triacetate.
For polyester dyeing, a stainless steel lid was bolted onto the top of the beam
O 0
dye machine and temperature was raised to 110 C (230 F). The rate of tempera-
o o
ture rise and cooling was the same as for those dyeings made at 99 C (210 F).
Reasonably good correlation of shade was obtained between the ten or twenty gram
swatch, made in 0.5 or 1.0 liter of dyebath, with the 400 gram dyeing, made 1n
eight liters of water in the pressure beam dyeing machine.
The individual laboratory dyeings for each dye/fiber combination were made
and compared in light and medium bright shades. There was no deleterious effect
120
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on the color of the dyeings made from the highest quality pilot plant effluent.
When the pilot plant effluent was essentially colorless, high quality dyeings
were obtained. Spectrophotometric evaluations confirmed the visual ratings of
acceptability. These instrumental readings were made using a "Spectroscan"
spectrophotometer integrated into an Applied Color System, Inc. ACS-500 comput-
er system.
COLORFASTNESS OF FABRICS DYED USING PILOT PLANT TREATED WASTEWATER
Based on these experiments, there was no detrimental effect on colorfast-
ness to washing, sublimation, crocking (rubbing), perspiration, oxides of
Nitrogen fading, ozone fading, or lightfastness (carbon arc), when dyeings were
made using essentially colorless pilot plant effluent for dyeing. These
evaluations included tests made on selected dyeings of dispersed dyes on
triacetate, basic (cationic) dyes on copolymer polyester, acid dyes on nylon,
a disperse blue dye on a design fabric made from a blend of both homopolymer
and copolymer polyester, premetallized dyes on nylon, a direct blue on nylon,
dispersed dyes on polyester, an optical brightener on polyester, and a differ-
ent optical brightener on nylon. The dyes used in this particular evaluation
with the exception of the direct dye on nylon, and a fluorescent disperse
yellow on copolymer polyester, were all expected to exhibit good colorfast-
ness. There were no unexpected developments in this series of evaluations.
SUMMARY
Laboratory dyeings were made using effluent from the complete pilot treat-
ment plant each time the effluent quality was essentially colorless. Consequent-
ly, dyeings were made over a number of days and water from several pilot runs
was used. These variables, notwithstanding color of the swatches dyed in pilot
plant effluent, matched the color on the control dyeings. There was every in-
dication that similar satisfactory dyeings could have been made using full si zed
production equipment and that the dyed fabric would have been shipped as first
quality product.
These laboratory dyeings confirmed that the pilot wastewater treatment plant,
operated in its entirety, did produce wastewater of sufficiently high quality
121
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to be reused in dyeing fabrics of man-made fibers of nylon, acetate, triacetate
and polyester. The dyeings made from this treated wastewater were equal 1n
quality, color, brightness and colorfastness to parallel dyeings made using con-
trol water from manufacturing process storage.
Residual color in the wastewater normally discharged to a receiving stream
proved to be the most difficult parameter to remove, as had been anticipated.
A satisfactory treatment scheme was developed to remove this residual color and
with it almost all BOD5, COD, TOC, metals, suspended solids, etc. The system
was also capable of effectively removing TKN. Wastewater was sufficiently treat-
ed to be reused in several dyeing processes as the vehicle for dyeing man-made
fiber fabrics satisfactorily.
122
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SECTION 9
PRELIMINARY DESIGN OF A ONE MILLION GALLON PER DAY TREATMENT PLANT
The application of pilot technology, as described in Section 7, to full-
scale operation was considered technically achievable. Current economic con-
straints at this particular manufacturing location made a full-scale advanced
wastewater treatment plant unattractive economically. However, there are
those who may wish to apply this technology to produce water of reusable
quality in manufacturing.
WASTEWATER TREATMENT PLANT DESIGN FLOW SEQUENCE
The preliminary design of a 1 MGD wastewater treatment plant has been pre-
pared to produce an effluent capable of being used as process water in a dye-
ing and finishing plant. This wastewater treatment plant would include a nine
hundred gallon-per-mlnute reactor/clarifier with provision for the addition of
alum and polyelectrolyte coagulant aids. The supernatant would be transferred
to a 50,000 gallon capacity clear well; heavy chemical sludge would be sent
to a holding basin for further treatment. Transfer pumps would then transfer
up to 1,642 gpm from the clear well to three dual media filters, (anthracite
and sand), ten feet in diameter. Table 48 and Figure 8 present the necessary
preliminary design data. The dual media filters' function is to remove coagulant.
The net effluent flow of 1210 gpm from the dual media filter would then
be treated by three nine-foot diameter activated carbon filters for color and
organic removals. Three eight-foot diameter organic traps would then receive
a net flow of one thousand gallons per minute for additional organic removal.
Three cation exchangers, eight feet-six Inches 1n diameter, would remove multl-
valent metals and other positively charged Ions such as residual catlonlc dyes.
The one thousand gallons per minute effluent from the cation exchangers would
flow to a degasifier, functioning with a 2800 cfm air flow to dislodge
123
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TABLE 48. DESIGN DATA FOR 1 MGD SCALE UP OF PILOT PLANT
REACTOR/
CLAR1FIER
EQUIPMENT (R/C)
No. of Units 1
Maximum Influent 900 Avg.
(GPM)
Mar.. Effluent/
Unit (GPH) 1642
Max. Effluent 164?
Media
Volume of Media/
Unit (Cu.Ft.)
Depth of Media
(Inches)
Diameter of
Column (Ft.)
Height of
Column (Ft. )
Chemical Feeds Alum
Polyelcctrolyte
Regeratlon or
Backwash
Reyonerant
1 Solution
Regenerant
Ibs. Rcyenerjnt/
Re yene ration
Backwash/HrqeniTfl-
tlon Waste GPD 5000*
DUAL MEDIA
FILTERS
(DMF)
3
1642
500
1000
Anthracite
.60-. 80 mra
Filter Sand
.45-. 60 mm
157
157
24
?4
10
6.0
-
Backwash
Only
-
-
-
30,000
ACTIVATED
CARBON
FILTERS
(GAC)
3
1210
500
1175
20 x 50
Mesh
Activated
Carbon
190
36
9
5.0
-
Backwash
Only
-
-
-
10,000
ORGANIC TRAP
(OT)
3
1000
500
1000
Dowex 11
175
4?
8
B.O
-
Backwash &
Regeneration
Nad
5*
525
40.000
CATION
EXCHANGER
(CE)
3
1000
333
1000
IR 120
434
92
R.5
14.5
-
Backwash &
Regeneration
A & B
H2S04
(A)2. (B)4
2170
75,000
ANION
AERATOR W/CLEARWELL EXCHANGER
(AC) (AE)
1 3
1000 1000
1000 350
1000 700
IR 47
245
60
8
9.75
__ —
Backwash &
Regeneration
Sodium
Carbonate
3t
1225
75.000
Simla.)' wasting r«itr
124
-------
ro
in
Figure 8. Process flow schematic - I mgd plant.
-------
entrapped CC^. Transfer pumps would then pump 1000 gallons per minute from
the degasifier clear well to three anion exchangers eight feet in diameter.
The anion exchange resins would remove excessive nutrient anions and any re-
maining, soluble, anion-charged residual color bodies. The above system would
produce a net flow of approximately 700 gallons per minute, or 1,000,000 gallons
per day.
The cost of the construction materials and equipment for the 1,000,000
gallon per day treatment plant is estimated to be approximately $1,500,000.
The construction and installation cost was estimated at $1,500,000 for a total
cost of $3,000,000. The land area needed for this project was estimated to be
approximately 3.5 acres including the lagoon.
The major difficulty with the preliminary design would be the handling of
the wastewater from the regeneration of various unit processes. The reactor/
clarifier would generate 5000 gallons per day of sludge which could be diverted
to an existing digester or concentrator, provided the existing facility was
adequate in size. The dual media filters would generate up to 30,000 gallons
per day of wastewater from backwashes which could be diverted to the equaliza-
tion lagoon of the existing wastewater treatment plant provided plant hydraulic
flow through the existing equipment would permit such a flow routing. The
effect of the existing system would have to be carefully evaluated prior to re-
routing this flow. The nature of this wastewater and the 10,000 gallons per
day from the activated carbon filters would probably be such that 1t would be
advantageous to discharge it in to an equalization lagoon prior to any treat-
ment. The 40,000 gallons per day of regeneration waste from the organic trap,
the 75,000 gallons per day each from the cation and anion exchangers; would
generate 190,000 gallons per day that would require separate disposal. The
possibilities of handling this regeneration wastewater with evaporators or
reverse osmosis are solutions to this disposal problem. The effluent from a
reverse osmosis system treating the regeneration wastewater could be diverted
back to the one million gallon per day treatment plant. Evaporators alone or
a reverse osmosis system would be expensive to install and operate. The fur-
ther treatment of the regenerant must be evaluated, on a site-specific basis,
for both technical and economic feasibility. Cost estimates for treating the
regenerant wastewater were not made. Another Important consideration with this
126
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type of wastewater treatment system 1s the land area required for Installation.
This consideration of land requirements/availability is site-specific and must
be evaluated on a case by case basis.
127
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
i. REPORT NO.
EPA-600/2-78-079
2.
3. RECIPIENT'S ACCESSION" NO.
4. TITLE AND SUBTITLE
Physical/Chemical Treatment of Textile Finishing
Wastewater for Process Reuse
5. REPORT DATE
April 1978
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
8. PERFORMING ORGANIZATION REPORT NO.
J.M. Eaddy, Jr. and J.W. Vann
9. PERFORMING ORGANIZATION NAME AND ADDRESS
J. P. Stevens and Company
P.O. Box 21247
Greensboro, North Carolina 27420
10. PROGRAM ELEMENT NO.
1B2036; ROAP 21AEC-02
11. CONTRACT/GRANT NO.
Grant S801211
12. SPONSORING AGENCY NAME AND ADDRESS
EPA, Office of Research and Development
Industrial Environmental Research Laboratory
Research Triangle Park, NC 27711
13. TYPE OF REPORT AND PE
Final; 3/73 - 2/78
PERIOD COVERED
14. SPONSORING AGENCY CODE
EPA/600/13
is. SUPPLEMENTARY NOTES T£RL-RTP project officer is Max Samfield, Mail Drop 62, 919/
541-2547.
16. ABSTRACT Tne report des cr ibes & demonstration of multimedia filtration as an effec-
tive tertiary treatment for biologically treated textile wastewaters from two adjacent
plants involved in dyeing and finishing fabrics of man-made fibers. Adding alum,
polyelectrolytes, and powdered activated carbon to the treated wastewater, just
ahead of multimedia filtration, reduced criteria pollutants and produced effluent
meeting NPDES requirements. Treated wastewater was further treated to provide
colorless effluent satisfactory for reuse in dyeing man-made fibers in a pilot plant
consisting of a coagulation/sattling/flltration unit followed by a five-column train
comprised of a sand filter, organic scavenging resin, granular activated carbon,
and cation and anion exchange resins. This water was satisfactory for dyeing a full
range of shades , including white and pastel colors on man-made fiber fabrics. Color
fastness was equivalent to that of standard control dyeings. Tramp color scavenging
ability of different man-made fibers was found to be quite variable. Essentially
colorless effluent is required for reuse in dyeing white or pastel shades on nylon
and triacetate fabrics. Although technical feasibility of further treating biologically
treated effluent to permit its use in critical dyeing and finishing operations was
demonstrated, the economics of commercial application are not attractive.
7.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.IDENTIFIERS/OPEN ENDED TERMS
c. COS AT I Field/Group
Pollution
Textile Industry
Textile Finishing
Dyeing
Waste Water
Water Treatment
Filtration
Manmade Fibers
Decoloring
Coagulation
Settling
Pollution Control
Stationary Sources
Biological Treatment
13 B
11E
13H
07D
9. DISTRIBUTION STATEMENT
Unlimited
19. SECURITY CLASS (This Report}
Unclassified
21. NO. OF PAGES
138
20. SECURITY CLASS (Tillspage)
Unclassified
22. PRICE
EPA Form 2220-1 (9-73)
128
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