U.S. DEPARTMENT OF THE INTERIOR
Federal Water Pollution Control Administration
i
J
r
j
t
i*~
f
1
_
_— ^— — —
vc
INDUSTRIAL WASTE PR!
PLASTICS MATERIALS
•••MM
•M^MK
m^m^mmi
-------
Other publications in the
FWPCA Publication No. I
FWPCA Publication No. I
FWPCA Publication No.
FWPCA Publication No.
FWPCA Publication No.
FWPCA Publication No.
FWPCA Publication No. I
FWPCA Publication No. I
FWPCA Publication No. I
Industrial Waste Profile series
Blast Furnace and
Steel Mills
Motor Vehicles and
Parts
Paper Mills
Textile Mill Products
Petroleum Refining
Canned and Frozen
Fruits and Vegetables
Leather Tanning and
Finishing
Meat Products
Dairies
I.W.P.-
I.W.P.-
I.W.P.-
I.W.P.-
I.W.P.-
I.W.P.-
I.W.P.-
I.W.P.-
I. W.P.-
It
2:
3:
4:
5:
6:
7:
8:
9:
FWPCA Publication No. I.W.P.-10
-------
THE COST OF
CLEAN WATER
Volume III
Industrial Waste Profiles
No. 10 - Plastics Materials and Resins
U. S. Department of the Interior
Federal Water Pollution Control Administration
For sale by the Superintendent of Documents, U.S. Government Printing Office
Washington, D.C, 20402 - Price 65 cents
-------
ii
PREFACE
The Industrial Waste Profiles are part of the National Requirements and
Cost Estimate Study required by the Federal Water Pollution Control Act
as amended. The Act requires a comprehensive analysis of the require-
ment and costs of treating municipal and industrial wastes and other ef-
fluents to attain prescribed water quality standards.
The Industrial Waste Profiles were established to describe the source
and quantity of pollutants produced by each of the ten industries stud-
ied. The profiles were designed to provide industry and government
with information on the costs and alternatives involved in dealing ef-
fectively with the industrial water pollution problem. They include
descriptions of the costs and effectiveness of alternative methods of
reducing liquid wastes by changing processing methods, by intensifying
use of various treatment methods , and by increasing utilization of
wastes in by-products or water reuse in processing. They also describe
past and projected changes in processing and treatment methods.
The information provided by the profiles cannot possibly reflect the
cost or wasteload situation for a given plant. However, it is hoped
that the profiles, by providing a generalized framework for analyzing
individual plant situations, will stimulate industry's efforts to find
more efficient ways to reduce wastes than are generally practiced today.
^^J Commissioner f
Federal Water Pollution Control Administration
-------
Industrial Waste Profile No. 10
Plastics Materials and Resins-SIC2821
Prepared for F.W.P.C.A.
IIT Research Institute
Technology Center
Chicago, Illinois 60616
FWPCA Contract No. 14-12-104
October 12, 1967
Federal Water Pollution Control Administration
October 1967
-------
lil
SCOPE OF MATERIAL COVERED
This technical study and financial analysis considered the
single-unit process, polymerization, Standard Industrial Classi-
fication (SIC) 28210. The several process steps involved, from
the synthesis of the monomer to the fabrication of the completed
plastic material, are under other allied SIC codes. The water-
borne wastes generated by and the renovation costs incurred
during polymerization are relatively low, compared with those
of the other closely allied process steps.
Total production under SIC 28210 in 1967 will be 14 x
10^ lb; at 6% compounded, this total is predicted* to grow to
26 x lo" lb in 1977. Current production generates a total of
113 x 10" lb of waste, expressed as 5-day biochemical oxygen
demand (BOD) . A total of 33 x 106 lb of BOD is untreated and
goes directly to watercourses. The remaining 80 x 106 lb of
BOD goes through water renovation systems, which remove 62 x
106 lb BOD; 18 x 106 of BOD passes through to the watercourse
because of the inefficiency of the water renovation systems.
Thus the grand total BOD level to watercourses in 1967
will be 51 x 106 lb, or 45% of the 113 x 106 lb of BOD gener-
ated. The anticipated BOD generation for 1977 is 202 x^ 106 lb.
On the basis of current removal (55%) by renovation equipment,
the anticipated BOD level to watercourses in 1977 is 90 x 106 lb.
The total cost for water renovation under SIC 28210 is
$2.2 x 106. This figure includes waste treatment capital goods
depreciation, $0.3 x 10*?, municipal charges for treating indus-
trial wastes, $0.6 x 10 . and industrial operating and mainten-
ance expenses, $1.3 x 10°. The in-place purchase cost of
capital goods in use for water renovation in 1967 is $7.4 x 106
(replacement value $7.9 x 106). The weighted economic life of
water renovation equipment is 24 years.
*IIT Research Institute study, 1967.
-------
IV
TABLE OF CONTENTS
Page
Preface ii
Scope of Material Covered iii
Table of Contents iv
Summary 1
1. SIC 28211 Cellulosics 9
2. SIC 28212 Vinyl Resins 18
3. SIC 28213 Polystyrene Resins and Copolymers 28
4. SIC 28214 Polyolefins 36
5. SIC 28215 Acrylics 50
6. SIC 28216 Alkyd and Polyester Resins 57
7. SIC 28217 Urea and Melamine Resins 64
8. SIC 28218 Phenolic Resins 74
9. SIC 28219 Miscellaneous Resins 84
-------
SUMMARY
INTRODUCTION
This profile study of Standard Industrial Code (SIC) 28210
represents one segment of the total analysis of major contribu-
tors of water-borne pollution. Since prior investigations of
this industrial classification and related fields have developed
only broad generalizations, our objective was to develop more pre-
cise data. Thus the purposes of this profile study ware (1) to
identify, quantify and qualify processes and wastes, gross waste
quantities, waste reduction practices, and waste reduction cost
information, (2) to summarize these various facets of the waste
picture, and (3) to make projections on future product growth.
This study, as well as the previous investigations, depended upon
the pollution contributor for the pertinent raw data. It is hoped
that future studies, such as complete water balances for individual
water basins, will find the results of our endeavor valuable.
Plastics and resins are chain-like structures known chemically
as polymers. All polymers are synthesized by one or more of the
following processes: bulk, solution, emulsion, and suspension. A
typical production reaction requires the addition of a free radical
initiator and modifiers to the monomer, the building block of the
polymer. This polymerization process creates relatively little
water-borne waste, compared with that of other chemical manufac-
turing processes. In most cases, the preliminary step in polymeri-
zation, the synthesis of the monomer,* creates considerably more
waste than the production of the polymer from the monomer.**
Because it is technically and economically advantageous, most
firms manufacture several different related chemical .products***
at one location and use a common waste disposal unit. It is not
economically advantageous to identify and qualify the waste from
each manufacturing process, so waste treatment is usually handled
as a common cost center. These costs are then entered into an
* The syntheses of the monomer is outside the scope of SIC 28210.
** For example, the cost of waste treatment for cracking ethane to
make ethylene (the monomer building block of polyethylene)
amounts to 0.60% of the value of the final product, polyethylene.
At HC/lb for polyethylene, this waste treatment cost amounts to
$2.5 x 10^ for a production of 3.8 x 10^ Ib of polyethylene manu-
factured per- year. There are no water-borne wastes generated
from the polymerization of polyethylene.
***For example, a typical chemical complex manufactures ethylene,
polyethylene, sulfuric acid, ethyl chloride, ammonia, nitric
acid, and phosphoric acid.
-------
overall burden rate. However, some firms do utilize a direct cost,
based upon loading, that is charged to each producing profit center.
In either case, it is often difficult for a plant sanitary engineer
to accurately determine the cost of water renovation for any given
manufacturing process. These manufacturing processes fall under
various Standard Industrial Codes.
THE STUDY
This techno-economic study was conducted by using the following
stratagem. For individual study by team specialists, SIC 28210 was
separated into nine, five-digit subdivisions, representing over 85%
of all plastic production.
'SIC 28210 Plastics Materials and Resins
SIC 28211 Cellulosics
SIC 28212 Vinyls
SIC 28213 Styrenes
SIC 28214 Polyolefins
SIC 28215 Acrylics
SIC 28216 Polyesters and alkyds
SIC 28217 Urea and melamines
SIC 28218 Phenolics
SIC 28219 Miscellaneous resins (urethanes,
epoxies, coumarone - indenes,
silicones, polycarbonates, acetals,
and nylon 6)
The major effort of this study involved the acquisition of
first-hand organized information from the producers of plastics.
Thus key production plants were visited, and the actual production
facilities, in addition to the water renovation facilities, were
physically surveyed. When possible, process flowsheets were ob-
tained directly from technical personnel at the plant site. In-
depth telephone interviews were conducted with resin manufacturers,
major pollution-control equipment manufacturers, water pollution
control chemical and service companies, government agencies, re-
search institutes, universities, and trade and professional associa-
tions. Related technical and economic research, pollution control
field work, and production experience resident at IIT Research
Institute were utilized.
In order to establish past production data and to forecast
future production levels, a comprehensive examination and analysis
of each of the nine, five-digit plastic subdivisions was conducted.
The individual and accumulated growths were plotted on three-cycle
semilogarithmic paper (Figure 1).
-------
RESULTS
Comprehensive analysis of the individual, five-digit plastic
subdivisions showed that the projected compounded growth rate for
SIC 28210 through 1977* is 6%. United States production of SIC
28210 and its predicted growth from 1962 are enumerated and illus-
trated in Figure 1 and Table 1.
The current total production of 14.25 x 109 Ib/yr generates
113 x 10^ lb of water-borne waste** expressed as five-day biochemi-
cal oxygen demand (BOD). Of the BOD generated, 55% (62 x 106 lb) is
removed by water renovation systems; the remaining 45% (51 x 10^ lb)
goes to watercourses. Of the 51 x 106 lb of waste that goes to
watercourses, no effort is made to treat 33 x 106 lb; the remaining
18 x 10° lb passes through treatment plants unremoved.
The predicted plastic production of 26 x 109 lb for 1977 will
generate 202 x 106 lb of BOD. By assuming a constant 55% removal,
the waste load to watercourses will increase from 51 x 10° in 1967
to 90 x 10° lb in 1977.
A detailed breakdown of wastes generated and costs incurred is
given in Table 2. The total current waste treatment cost of removing
62 x 106 lb of BOD is $2.2 x 106/yr. This figure includes $0.6 x
10" sewer charges to manufacturers utilizing municipal facilities
for water renovation, $0.3 x 10° for industrial water treatment
capital goods depreciation, and $1.3 x 10° for industrial operating
and maintenance of water-treating equipment. The in-place purchase
cost of capital goods in use for water renovation in 1967 is $7.4 x
10°; the replacement value is $7.9 x 106.***
The weighted average economic life of water renovation equip-
ment is 24 years.
DISCUSSION
The highly subjective projections on unit growth rates and the
prognostications on treatment levels and related costs given above
demand some elucidation.
* Modern Plastics (1965) predicts a growth to 22 x 109 lb in 1975.
Plastic World (1966) predicts a growth to 25 x 109 lb in 1975.
An IITRI study (1967) predicts a growth to 25 x 109 in 1975.
U.S. Dept. of Commerce, BDSA (1967), predicts a growth to
20 x 109 lb in 1975.
** It is assumed that 1 lb dry weight of industrial waste generates
0.75 lb of BOD.
***Chemical Engineering Plant Cost Index (fabricated equipment)
Sept. 1967.
-------
100
100
I 1 1 1 1 1 1
1962 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977
Figure 1
U.S. Production SIC 28210 in Billions of Ibs/yr
-------
Table 1
PLASTICS AND RESIN (SIC 28210) PRODUCTION IN BILLIONS OF POUNDS
g
Total Production. 10 Ib/vear
Cellulosics'
Year (SIC 23211)
1962 0.48
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
0.48
0.49
0.49
0.49
0.50
1.50
0.51
0.51
0.52
0.52
0.53
0.53
0.54
0.54
0.55
Viryls
(SIC 28212)
1.55
1.75
2.00
2.25
2.50
2.80
3.10
3.45
3.65
3.84
4.10
4.40
4.80
5.00
5.10
5.20
Etyrenes
(SIC 28213)
1.25
1.50
1.72
1.90
2.00
2.25
2.50
2.80
3.15
3.30
3.50
3.65
3.85
4.20
4.30
4.40
PoJyolef ins
J SIC. 2821.41
2.00
2.28
2.65
3.40
3.85
4.35
4.80
5.20
5.85
6.20
6.70
7.30
7.80
8.60
a. 90
9.10
Type
Acrylics
iSIC 28215)
0.13
0.20
0.22
0.24
0.23
0,29
0.32 .
0.34
0.37
0.39
0.42
0.44
0.46
0.49
0.50
0.52
of Resin
Polyesters
and AlXyds
(SIC _282161
0.68
0.76
0.84
0.92
1.05
1.10
1.25
1.30
1.40
1.45
1.50
1.55
1.60
1.68
1.75
1.80
Urea and
Melamines
(SIC 28217)
0.49
0.51
0.55
0.59
0.62
0.66
0.68
0.72
0.74
0.77
o.so
0.83
0.86
0.89
0.92
0.95
Phenol ics
(SIC 28218)
0.69
0.76
0.84
0.90
0.99
1.05
1.12
1.18
1.22
1.28
1.30
1.32
1.35
1.38
1.42
1.50
Miscellaneous
(SIC 28219)
0.65
0.76
0.90
1.03
1.06
1.25
1.32
1.45
1.65
1.68
1.70
1.76
1.80
1.85
1.90
2.00
Total
(SIC 28210)
7.97
9.00
10.21
11.72
12.84
14.25
15.59
16.95
18.54
19.44
20.54
21.78
23.05
24.63
25.33
26.02
Includes regenerated material, e.g., cellophane.
-------
Table 2
COST OF WASTE TREATMENT IN 1967
sic je:
Production, 109 Ib/yr 14.25
Waste water, 109 gal/yr 24
waste produced. 106 Ib/yr
% Treated
Waste treated, ID6 Ib/yr
Treatment coat, e/lb BOD
Capital depreciation. 6/lb BOD
Operation and maintenance, C/lb BOD
Treatment cost, $/10 gal
Capital depreciation. S/106 gal
Operation and maintenance, S/10 gal
Treatment cost. 103 $/yr 2177
Capital depreciation, 103 $/yr 312
Operation and maintenance. 10 $/yr 1320
••.• r'l SIC 282Ub
0.50
15
10
40
2.5
4
1.8
2.2
30
13
17
180
80
100
SIC 28212°
2.80
2.80
28
31
8.68
9
1
8
-
-
889
124
765
SIC 28213d SIC 28214° SIC 28215*
2.25 4.35 0.29
3.38 0.004 0.015
2.25 - 0.174
95 - 95
2.25 No waste 0.17
22
19
3
119 - 2670
2320'
350
382 0 38
- 0 33
0 5
SIC 282169
1.10
2.30
6.5
63
4.2
-
-
-
-
-
-
181
8
18
SIC 2B2:
3.66
0.062
36
90
32
-
-
-
197
105
92
11
3.3
2.9
I7h SIC 282]
1.05
0.077
52.5
90
47
-
-
-
6600
650
5950
462
51
408
L81 SIC 28219^
1.25
0.603
0.31
90
0.28
12
5
7
483
184
299
34
13
21
ntfaste water, expressed In gal/yr. does not Include cooling water. Concentrations of waste are extremely variable; a "percent treated" calculation would
be misleading.
Waste produced, in Ib/yr, is con-posed of Ib BOD and Ib dry wt. of a specific waste, etc., and is not an accumulative figure? nor can one form of waste be
directly related to another form Df waste.
Percent treated is calculated from and relates directly to waste generatedt the increments are not accumulative.
Treatment cost, in C/lb of BOD treated, Is calculated when waste is expressed in BOD and accurate relevant data are available. A weighted average is
not meaningful.
Treatment cost, total treatment in $/yr, include* municipal sewer charges in the total treatment cost. No costs are entered for depreciation or operations
and maintenance for municipal sewer charges. These costs are accumulative.
Sfaste is in BOD. Production is 2/3 regenerated cellulose (60% of waste treated) and 1/3 cellulose (35% of waste treated).
cwaste composed of 28 x 106 Ib BOD and 4.1 x 10 Ib suspended solids. Treatment 54* primary treatment ($114,000/yr> , 31% secondary (S775.000/yr),
and 15% untreated.
"waste is expressed in Ib dry material. All waste is treated in municipal plants; coats are based on sewer charges.
*No water waste produced.
Waste in BOD; difficult to treat acrylic emulsion.
"waste in BOD. Treatment cost based upon sewer charges for 1.1 x 10 gal/yr at $113/10 gal; primary treatment for 132 »• 10 Ib produced at 2 * 10 5/lb
produced; and 7.7 x 106 IQ produced at 4 * 103 $/lb produced for land disposal.
''waste in Ib of urea, melaralne, and formaldehyde. Treatment costs based upon municipal, primary, 63% and lagoons 27%.
Sfaste in Ib of phenol. Treatment costs baaed on solvent extraction treating, 70%; lagoons, 10%; thermal incineration- 10%; and municipal, primary, 10%.
^Waste in Ib of BOOt waste water from epoxy, 425 * 10 gal/yrt polycarbonates, 40 » 10 gal/yr; silicons, 60 x 10 gal/yr; and coumarone-indene,
78 x 106 gal/yr. Treatment costs and waste produced data only available on coumarone-indene.
-------
For this study, 35 significant parameters were utilized to
evaluate waste loading. Of these, BOD was the most representative
of the waste load, as well as the one criterion most universally
utilized for measurement. Because the major pollutional effect of
organic wastes in a stream is their consumption of dissolved oxygen
under the influence of microorganisms living in the stream environ-
ment, the rate and extent of oxygen depletion is customarily evalu-
ated by the BOD test. Although BOD is currently the best test
available, it is not an adequate parameter of organic loading, and,
as a production monitor, it is "five days late."
The BOD test involves, first, a measurement of the dissolved
oxygen initially present in the sample of water containing the waste
under study. This sample may be from the polluted stream, or it may
be a batch of special water to which a known amount of waste has
been added. Other samples of mixed water and waste are then incu-
bated in the presence of suitable microorganisms and nutrients in an
appropriate environment, usually for 5 days at 20°C. The remaining
dissolved oxygen is then measured, and the amount of dissolved
oxygen consumed during the test is reported as milligrams of oxygen
per liter of water. .There are many possible interferences in the
BOD test; e.g., toxic materials invalidate it completely unless they
can be detoxified or diluted to the point of negligible effect.
It is customarily accepted that the five-day BOD test repre-
sents 70% of the organic load* in water from aqueous systems con-
taining sanitary waste. For industrial wastes, however, BOD test
data must represent something less than 70% because the diverse
constituents of industrial waste complex the biodegradation process
and too often invalidate the test. The exact percentage varies
sharply, depending upon the biodegradability of the waste and
whether the ideal bacteria have been utilized in seeding the test.
The waste-loading data accumulated in this study are as accurate as
possible, but it must be remembered that these data are based upon
a test that was developed for sanitary waste and that it is inade-
quate for chemical industrial waste.
Many renovation systems in current use were designed and
developed to produce a water whose quality will not meet the stand-
ards of the next decade. Most fluidized culture systems for housing
the biological oxidation process (conventional activated sludge,
tapered aeration, contact stabilization, extended aeration, aeration
ditch, completely mixed systems, oxidation ponds, aerated ponds,
trickling filter) were developed to treat municipal wastes. This
type of waste contains a relatively low fraction of readily bio-
degradable soluble organics with balanced nutrients. But industrial
wastes are high in slowly biodegradable soluble organics without
balanced nutrients. Therefore upgrading the effluent quality from
*Standard methods list five-day BOD for 300 mg/liter of glucose as
224 ± 11 mg/liter, or 70% of the theoretical oxygen demand of
321 mg/liter.
287-033 O - 68 - 2
-------
these marginally designed systems will reveal engineering inade-
quacies and subsequently develop waste treatment quality and cost
problems.
Increasing the percent waste removal will involve a dispro-
portionate increase in the cost per unit of waste removed in
improperly or inadequately designed equipment. The current cost
of efficient primary plus secondary treatment for a given industrial
waste is in some cases five times as great, per unit volume of
comparable waste water treated, as for token primary treatment
systems built 10 years ago. The data available on comparable raw
wastes and similar removal efficiencies were not sufficient to
accurately calculate comparable costs per unit of waste removed,
but, in general, those plants recently designed and built reflect
total treatment costs considerably higher for a comparable volume
of water treated. The data available indicate that the initial cost
of recently built equipment, which is designed to reduce effluent
waste loads within anticipated legal limits, was considerably higher
than that of older units built for less rigorous standards.
The data accumulated in this study, i.e., waste loads gener-
ated, percentage removed, and costs incurred, were supplied by the
same industrial organizations that are generating these wastes. It
is possible that some of the data received favorable interpretation
before release. For example, the amount of waste attributed to
intermittent spills and machine and floor washdown for specific
processes was difficult to isolate and evaluate.*
Ultimate disposal of solid wastes generated by bi©degradation
is customarily handled by using the waste for land fill. With the
increasing value of land, it can thus be assumed that the cost of
ultimate disposal will increase. For each pound of BOD, approxi-
mately one-half pound of solid waste is generated. It is known that
four industrial plants are disposing of their solid waste by inciner-
ation. The cost of disposal by incineration is 6C/lb of dry waste,
or 3C/lb of BOD removed.
The data available on some plastics were not sufficient to
develop a total figure for percent of industrial waste water treated
in municipal systems.
The anticipated growth of SIC 28210 is calculated at 6% com-
pounded per year, although the growth rate over the past 20 years
has ranged between 12 and 16% compounded per year. Thus any waste
treatment program developed for the coming decade could prudently
contain a contingency for accommodating a growth rate as high as
15% compounded per year.
*One plant studied created its entire waste load from spills and
washdown. The waste treatment costs amounted to 0.25% of the
product value; at a product value of $8 x 10 , this particular
source of waste cost $20 x 103/yr for removal.
8
-------
SECTION I
SIC 28211 CELLULOSICS
Cellulosics, which are plastic materials produced from cellulose,
range from regenerated cellulose, or cellophane, to the nitrocellulose
in gun cotton. The total demand for cellulose in this country in 1963
was about 480 million pounds. Of this, almost three-quarters was used
for the production of cellophane film. The remainder was used for
other cellulosics, mainly acetates.
Cellulosic plants are located in fairly remote parts of the country
along large streams. These plants make little of anything else, and
the effluent outputs can easily be identified. The BOD in the waste
can be attributed to cellulose. Precise data are lacking, but the
levels are high.
Neutralization has been practiced for years; secondary treatment
is a recent innovation.
The product growth curve is on, and will remain on, a plateau
over the below indicated period:
Production
Year 109 Ib/yr
1962 0.48
1963 0.48
1965 0.49
1967 0.50
1970 0.51
1977 0.55
PROCESSES AND WASTES
A. Fundamental Manufacturing Process
Cellulosics are manufactured from cellulose. Either cotton linters
or purified wood pulp is used as the raw material, although today very
little cotton linters is used. In either case, the process is the same.
1. Regenerated Cellulose
The largest portion of cellulose is used for the production of
cellophane, or regenerated cellulose. In the United States, cellophane
is made almost exclusively by the xanthate process, whereas in Europe,
the cuprammonium process is widely used. The xanthate process is a
solution process in which cellulose is treated with caustic soda and
carbon disulfide in water. The resultant solution of cellulose xanthate
is coagulated, and cellulose is regenerated in the form of a continuous
film, or filament, by acidification. Much of the operation is propri-
etary, although the overall process is well known. The level of waste
-------
has been reported to range from 0.015 to 0.01 BOD/lb of product
produced. No major changes in manufacturing operations have been made
in the last twenty years.
2. Cellulose Esters
The remainder of cellulosic production is largely made up of the
esters: cellulose acetate, cellulose propionate, cellulose butyrate,
and their copolymers. Little cellulose nitrate is made. The market
for this type of cellulose thus seems to be less than 2% of the total,
and there is no apparent trend to increase.
Cellulose acetate is made in a suspension process from cellulose
and acetic anhydride in a sulfuric acid solution. ' The reaction is
carried out to the triacetate stage ; the product is then de-esterified
to a suitable level, precipitated, washed, bleached, and dried. A
diluent of acetic acid or methylene dichloride is used. The process for
making cellulose acetate is basically the same as it has been for the
last 20 years.
The proprionate and the butyrate are made by essentially the same
process. All three can be made in the same plant. Later they are made
together as copolymers.
Figures 2 an<3 3 are flow diagrams of these processes.
B. Significant Water Wastes
This industry is responsible for a relatively high production of
biodegradable cellulosic waste materials, sulfates, and heavy metals.
1. Regenerated Cellulose
The level of generated waste has been reported over a range of 0.015
to 0.10 Ibs/lb product manufactured. The percent of product going to
waste has gradually been decreasing because of the increasing efficiency
in plant operations.
The bulk of the remainder of the waste is reported to be H?SOA,
Na2SO4, and heavy metals. Neutralization of acids with caustic is a
common practice. In some operations CSj is considered to be a problem;
CS2 is a poison which, if present, would interfere with the biodegrada-
tion of the waste. Scrap cellophane is also a waste that requires
disposal; it is buried or incinerated.
2. Cellulose Esters
The waste from acetate production is similar to that from cellophane
production. In addition, acetic acid (and methylene dichloride) are
present as organic wastes, but there is no CS2, Na^SO., or NaOH. The
recovery in the acetic cycle is better than 90%. The cellulose loss is
approximately 1 to 8%, depending on the quality of pulp. Methylene
dichloride losses are less than 2% in the processes that use it. The
process for making cellulose acetate is basically the same as it has been
for the last 20 years. The wastes from the propionate are basically
the same as those from the acetate but are slightly greater for the
10
-------
Caustic
Caustic
Carbon
Disulfide
Excess
Carbon
Disulfide
Acid
Cellulose
Caustic
5
I
Mercerization,
Pressing,
Shredding, Aging
1
Xanthation,
Dissolving
I
Ripening,
Deaeration,
Filtration
Spinning,
Coagulation,
Washing,
Bleaching
1
Regenerated
Cellulose
Waste
Caustic, Scrap
Cellulose, Sul-
furic Acid,
Sodium Sulfate
Figure 2
FLOW DIAGRAM OF THE PRODUCTION OF REGENERATED CELLULOSE
11
-------
Acetic Acid, Acetic
Anhydride, Sulfuric
Acid, Cellulose
Acetic
Anhydride
Regeneration
1
Cellulose
Triacetate
1
Acetic Acid
Recovery,
Sugar Removal
P recipitation
1
a
al
I
Cel
Ac
Acetate
i
Waste
Cellulose,
Acetic Acid,
Magnesium
Sulfate
Figure 3
FLOW DIAGRAM OF THE PRODUCTION OF CELLULOSE ACETATE
12
-------
same amount of product. A similar situation probably exists for the
butyrate.
C. Reuse of Process Water in 1964
There is no reuse of process water.
D. Industry Subprocess Mix
There is no subprocess mix for the production of either
cellophane or cellulose esters.
E. Difficult Waste Control Problems of Subprocesses
There are no subprocesses.
F. Levels of Technology
1. Typical
Typical technology for cellophane production is the xanthate process,
a solution technique. Typical technology for the production of other
cellulosics is esterification by suspension techniques.
2. Older
The older technology for both types of cellulosics is the same as
the typical technology.
3_._ Advanced
There are no indications of any advanced technology.
Range of Plant Size,
Technology Level 10 Ib/yr
Typical and older 10-100
for regenerated
cellulose and
cellulose esters
No reliable data are available for percentages of small, medium, and
large plats.
13
-------
II. GROSS WASTE QUANTITIES BEFORE TREATMENT OR OTHER
DISPOSAL
A. Waste Quantities and Volumes for One Plant
Typical Technology
Wasteload, Wastewater Volume,
106 Ibs BOD/yr 109 gal/yr
Cellophane 0.3 0.45
(small plant,
15 x 106 Ib/yr
Cellulose Acetate 0.72 1.08
(medium plant,
36 x 106 Ib/yr
There is no significant variation in loadings caused by shift,
daily, or seasonal changes.
There is no significant difference in unit waste production for
plants of significantly different production output.
B. Total Waste Quantities^ and Wastewater Volumes
Wasteload, Wastewater Volume
106 Ih fiOD.yr 109 gal/yr
Regenerated 6.4 10
cellulose
Cellulose 3.2 5
esters
Total Waste and Wastewater Quantities/Unit of
Physical Product
Wasteload, Wastewater Volume,
Ib BOD/lb product gal/lb product
Regenerated 0.02 30
cellulose
Cellulose 0.02 30
esters
14
-------
Total Waste Quantities and Wastewater Volumes
Produced in Base Year 1963
Wasteload, Wastewater Volume
106 Ib BOD/yr 109 gal/vr
Regenerated 6.4 10
cellulose
Cellulose 3.2 5
esters
E. Pro lee ted Gross Waste_s__ a_nd Wastewater Volumes
Year
1969 1969 1970 1971 1972 1977
Wasteload 9.6 9.8 9.8 10 10 10.5
106 Ib BOD/yr
Wastewater volume 15 15.3 15.3 15.6 15.6 16.5
109 gal/yr
F. Seasonal Waste Production Patterns
Seasonal variation in waste production are not significant.
Production is maintained 24 hr a day, 7 days a week. Future seasonal
changes are not anticipated. Variations in waste production due to
variable demand for cellulosics are possible.
III. WASTE REDUCTION PRACTICES
A. Processing Practices
1. Waste Reduction Efficiency (%) of a Given Subprocess
Relative to Alternative Subprocesses
There are no subprocesses.
2. Sequential Requirements and Interdependencies
of Processes Affecting Waste Production
The proprietary and complex nature of the processes involved prevent
an intelligent, accurate answer to this question.
15
-------
B. Treatment Practices
1. Normal Removal Efficiency {%) of Waste Treatment
Methods in Treating Waste from a Plant of
Typical Technology
The efficiency of a waste treatment plant practicing secondary
treatment is 70%.
One common practice in this industry is to locate near a river,
use the river water on a once-through basis, and discharge the wastes
directly to the river. Waste treatment seems to be a very recent
development. Many of the producing plants are located in remote areas
where the streams can accept and handle a high waste load. For these
and other reasons, we estimate that slightly less than 40% of production
practices waste treatment; most of these installations are of recent
vintage. Newer treatment methods vary. In one plant, €82 is not
considered a problem; in another, CS is rendered innocuous before
discharge. This plant's spent acid2is neutralized by combination
with a basic effluent from another process. Limestone neutralization
of the cellophane spent acid is used when necessary.
2. Rate of Adoption of Waste Treatment Practices
Estimated % of Plants
Treatment Employing Treatment Method
1950 1963 1967 1972 1977
Neutralization 10 50 80 100 100
Contact 5 20 40 80 90
stabilization
Most treatment plants that do not now have treatment facilities
reportedly have plans for total waste treatment methods to be completed
within a few years.
3. Combined Wastes
a. Percentage of Waste Discharged to Municipal
Sewers
Little or no waste is discharged to municipal sewers.
b. Waste Removal Problems Caused by Combining
Industrial with Municipal Wastes
Combination of cellulosic wastes with municipal wastes is technically
feasible if the plant is located near a large municipality. Neutraliza-
tion, coagulation and sedimentation would be necessary before introduc-
tion into a municipal system. The natural nutrients found in municipal
sewage would be a benefit to the biodegradation of the cellulosic waste.
Unless the municipal system were specifically designed for a high
hydraulic loading. (30 gal. waste water per pound of product) a typical
municipal system could easily be over loaded with the waste from a
typical cellulose producing plant.
16
-------
C. Bv-Product Utilization
There are no by-product uses of wastes that reduce wasteloads
reaching watercourses nor is there a likelihood of any being developed
and marketed in the next 10 years.
D. Base Year Net Waste Quantities
No accurate data are available to permit calculation of net waste
quantities reaching watercourses in 1963. It is estimated that
9.6 x 106 Ib BOD were produced and that 7.5 x 106 Ib reached water-
courses in 1963.
E. Projected Net Waste Quantities
No accurate data are available to permit calculations of projected
net waste quantities. Well-designed secondary treatment plants are
approximately 70% efficient in BOD removal.
IV. WASTE REDUCTION OR REMOVAL COST INFORMATION
A. Replacement Value* and ;ojiua]^poeratin^ and Maintenance
Expenditures of Existing Waste Removal Facilities
Treatment cost 180 x 103 $/yr
Capital goods depreciation 80 x 10-, $/yr
Operating and maintenance IOC .0° 5/yr
B. Capital Cost and Economic Life ot Processing and
Waste Removal Treatment Equipment
Capital cost $1.6 x 106
Economic life 20 years
*Data on age and replacement value is not accurately known.
17
-------
SECTION 2
SIC 28212 VINYL RESINS
The homopolymers and copolymers of vinyl chloride are among the
oldest and the most versatile thermoplastic resins. During the past
two decades, there has been a steady growth in the production and use
of a wide variety of vinyl resins. During the past few years, the
growth rate of this industry has been estimated at about 8 to 12%.
The total production capacity was about 1.6 billion Ib/year during
1963, and it is currently over 2.5 billion Ib/year. There has been
very little change in the manufacturing techniques and equipment em-
ployed in this industry during this growth period. The production of
the resins is essentially by means of batch operations. Among the
major polymerization processes available for the manufacture of vinyl
resins, i.e., suspension, emulsion, solution and bulk processes, the
suspension method is the most widely used. The latter accounts for
over 85% of the total polyvinyl chloride manufacture.
The production capacity of the vinyl resins during the past five
years and the projected figures for the next ten years are as follows:
Production,
Year 109 Ib/yr
1962 1.55
1963 1.75
1965 2.25
1967 2.80
1970 3.65
1977 5.20
I. PROCESSES AND WASTES
A. Fundamental Manufacturing Process
The fundamental method employed for the manufacture of vinyl
chloride polymers and copolymers can be one of the following three:
(1) suspension, (2) emulsion, or (3) bulk polymerization. Suspension
polymerization is the most widely used process for manufacturing vinyl
resins in terms of the variety and quantity of polymer products produced
and accounts for 85 to 90% of the total vinyl resins produced. In this
method, the monomer is dispersed as small droplets into a stabilized
suspending medium consisting of water containing 0.01 to 0.50% by wt.
(on the basis of the monomer weight) of the suspending agents such as
polyvinyl alcohol, gelatin, and cellulose ethers.
18
-------
The suspension is then heated in a reactor in the presence of
catalysts such as the benzoyl, lauroyl, and tertiary-butyl peroxides
(0.1 to 0.5% by wt. of the monomer) in order to initiate polymerization.
When polymerization is complete, the polymer suspension is taken to a
blow-down tank or stripper where residual unreacted monomer is recovered.
The stripped polymer is then transferred to a blend tank where it is
mixed with sufficient other batches to form a lot. Finally, the polymer
slurry mix is pumped to centrifuge where it is washed and dewatered.
The product is then dried in rotary driers. A simplified flow diagram
for the suspension process for polyvinyl chloride is shown in Figure 4.
It should be noted that a highly guarded factor in this process is the
suspending agent.
The emulsion polymerization process accounts for about 10% of the
total vinyl resins produced. This method consists of solubilization
and dispersion of the monomer and dispersion of the polymer in the
solvent phase. The solvent is usually water, although in some cases
cyclohexane and tetrahydrofuran are used. When polymerization is
complete, a milk-like latex of permanently dispersed polymer is ob-
tained from which the polymer particles are recovered mostly by spray-
drying or in some cases by coagulation and centrifugation. The emulsi-
fiers consist of a wide variety of soaps or surfactants, and the initiators
consist of persulfates, hydrogen peroxide, and several redox systems.
Bulk and solution polymerization methods are not being widely used
for the manufacture of polyvinyl chloride.
B. Significant Water Wastes
Since suspension polymerization constitutes the most widely em-
ployed process for polyvinyl chloride ( 85%) , significant wastes from
this method will be considered. In the emulsion process, which uses
water as the dispersion medium, the waste products are mostly dis-
carded into the atmosphere. However, when solvents such as hexane and
tetrahydrofuran are used, effluent wastes have to be considered.
The effluent stream from the centrifugation step (see Figure 4)
contains the majority of the contaminants from the plants. The impurities
in the effluent stream include: (1) suspending agents, (2) surface-
active agents, (3) catalysts or initiators, (4) small amounts of un-
reacted monomer, and (5) significant amounts of very fine particles of
the polymer product. Since the suspending agent and catalyst concen-
trations are closely guarded, proprietary information, the nature and
extent of their presence in the effluent streams can only be indirectly
evaluated by means of BCD and COD data obtained from the industry. In
addition to these contaminants, there may be small amounts of phenol,
sodium phenolate, and sodium hydroxide, which could come from the
purification of the monomer. It is also possible that chlorinated
organic solvents, such as carbon tetrachloride and chloroform, which are
included in the starting mixture to arrest the polymerization at any
desired point, might find their way into the effluent streams.
19
-------
0)
•o
o
U O-H
H 0)CO
c
•H
>
Vinyl
Chloride
Mixing
Tank
v
Reactor
Stripper
Blend Tank
Centrifuge
Dryer
Polyvinyl
Chloride
Waste
Water
Figure 4
FLOW CHART FOR POLYVINYL CHLORIDE PRODUCTION
20
-------
Data on the average composition and concentration of the water
wastes from the vinyl resin industry are presented later in this sec-
tion.
Air-discharged wastes may be considered negligible in the case of
suspension polymerization, which is the most widely used process for the
vinyl chloride homo- and co-polymers.
C. Reuse of Process Water in 1964
Waste waters from polyvinyl chloride industries are not being
reused. After appropriate treatment, to decrease the contaminant
present in the effluent to a low and acceptable value, the effluent
waste waters are discarded into municipal sewers or river streams.
In the case of solution polymerization, 90 to 95% of the solvent is
being reused.
D. Industry Subprocess Mix
Suspension polymerization is the most widely used method for
the manufacture of polyvinyl chloride. However, for the production
of copolymers, emulsion and solution polymerization are being employed
to a significant extent. There has been little change in the manufac-
turing methods and technology of the vinyl resins during the past 17
years, and it is believed that no drastic changes are expected in the
foreseeable future. Therefore, the character of the waste effluents
may not be expected to change to any significant degree in the
coming 10 years. The waste water volumes might vary with the increase
in total production of the resins.
E. Difficult Waste Control Problems of Subprocesses
This is not applicable.
F. Levels of Technology
1. Typical technology is described in Section IA.
2. Older technology is the emulsion process.
3. Advanced technology would be solution polymerization.
Range of Plant Size, Plant Size, %
Technology Level 10° Ib/yr Small Medium Large
Typical 2-200 40 37 23
(suspension
process)
Older (emulsion) 2-100 90 10
Advanced 2-109 90 10
(solution and bulk)
21
-------
II. GROSS WASTE QUANTITIES BEFORE TREATMENT OR OTHER DISPOSAL
A. Waste Quantities and Volume for an Average Size Plant Producing
100 Million Ib of Vinyl Resins per Year
Waste Load,
106 Ib/yr Waste Water Volume,
BOD SS 10b qal/vr
Polyvinyl chloride 1.0 0.15 100-200
In general, loadings are fairly steady. No significant changes
were indicated in daily, monthly, or seasonal handling.
No significant changes in the character and pattern of the wastes
and waters are expected for the next 10 years. However, the gross
wastes and waste water volumes are subject to changes as a function of
increased production.
B. Total Waste Quantities and Waste Water Volumes
Waste Load,
106 Ib/vr Waste Water Volume,
SS BOD COD 10^ qal/vr
Vinyl polymers 3.5 23.3 14 2.33
C. Total Waste and Waste Water Quantities per Unit of Physical
Product
Waste Load,
Ib/lb product Waste Water Volume,
SS BOD COD gal/lb
Vinyl polymers 0.0015 0.01 0.006 1-2
D. Total Waste Quantities and Waste Water Volumes Produced in Base
Year 1963
Waste Load,
10° Ib/vr Waste Water,
SS BOD COD 109 gal/yr
Vinyl polymers 2.4 16 9.6 1.6
.22
-------
E. Projected Gross Wastes and Waste Water Volume
Waste Load,
106 Ib/yr Waste Water Volume,
Year BCD SS COD 109 gal/yr
1968 23.3 3.5 14 2.33
1969
1970
1971
1972 46.6 7.0 28 4.8
1977 50.0 8.0 31.0 5.2
F. Seasonal Waste Production Patterns
There are no seasonal variations in the patterns of waste production
III. WASTE REDUCTION PRACTICE
A. Processing Practice
1. Waste Reduction Efficiency of a Given Subprocess Relative to
Alternative Subprocess
There are no subprocesses involved in vinyl polymer production.
2. Sequential Requirements and Interdependences of Processes
Affecting Waste Production
This is not applicable.
B. Treatment Practices
1. Normal Removal Efficiency (%) of Waste Treatment Methods in
Treating Waste From a Plant of Typical Technology
Normal Removal
Efficiency, %
Removal Method BCD COD SS
Primary clarification <1 ^1 98
method
Total treatment 88 90 98
involving activated
sludge method
23
287-033 O - 68 - 3
-------
2. Rate of Adoption of Waste Treatment Practice
Estimated % of Plants
Employing Treatment Method
Method 1950 1963 1967 1972 1977
Primary clarification — — 60
Total Treatment — — 40 >90
There are no sequential applications of the processes that would
affect waste reduction.
There are no substitute techniques in use.
There are no interdependences among waste removal techniques
that affect costs or relative efficiencies.
3. Combined Wastes
a. Percent Wastes Discharged to Municipal Sewers
% Waste Discharged
Year to Municipal Sewers
1950
1963 ^ 60
1967 rv 60
1972
b. Waste Removal Problems Caused by Combining Industrial
with Municipal Wastes
A number of vinyl resin manufacturers do in fact discard waste waters
into municipal sewers after a primary treatment. Apparently this arrange-
ment has been found technically feasible. There are no difficult prob-
lems created by this practice.
Primary treatment aimed at removing the fine particles of the
resins is considered necessary, and this is being done by most of the
resin manufacturers.
C. By-product Utilization
There are no by-product uses of wastes that reduce waste loads
reaching water courses.
No new by-products are likely to be developed and marketed in
1968 to 1977.
24
-------
Table 2
SUMMARY OF BASE YEAR AND PROJECTED NET WASTE LOADS
Type Gross Waste
of Quantity Generated,
Year Waste 105 Ib/yr
1963 BOD 16.0
SS 2.4
COD 9.6
1968 BOD 23.3
SS 3.5
COD 14.0
1972 BOD 46.0
SS 7.0
COD 28.0
1977 BOD 50.0
SS 8.0
COD 31.0
% of Waste
Reduced
98
35
98
36
75
99
77
84
99
86
Net Waste
Quantity Discharged,
1Q6 Ib/yr
15.8
0.05
9.5
15.1
0.07
9.0
11.5
0.07
6.4
8.0
0.08
4.3
25
-------
Base Year Net Waste Quantities
Net Waste Quantities
Reaching Water Courses
in Base Year 1963,
Waste 106 Ib/yr
BOD 6.4
SS 0.1
CCD 3.9
Projected Net Waste Quantities
These data are given in Table 3.
IV. WASTE REDUCTION OR REMOVAL COST INFORMATION
Replacement Value and Annual Operating and Maintenance Expenditures
of Existing Waste Removal Facility (1966)
Treatment cost
Capital good depreciation
Operating and maintenance
889 x
124 x
10:
10-
$/yr
$/yr
765 x 103 $/yr
B.
Capital Cost and Economic Life of Processing and Waste Removal
Treatment Equipment
Annual
Operating and
Capital Maintenance
Typica1 Techno1oqy Cost < $ Expenditure, $
Small Plant
End-of-line
treatment
Medium Plant
End-of-line
treatment
Large Plant
End-of-line
treatment
40,000
200,000
400,000
Total Capital Cost
Economic Life
2,000
90,000
150,000
$2.5 x 10
20 yr
Economic
Life,
years
40
20
20
There are no reductions in processing costs due to recovery of any
possible by-product or unreacted monomer and solvent.
26
-------
The question of incremental costs in applying different techniques
to existing plants does not arise since the manufacturers do not an-
ticipate any change in techniques for the projected period.
27
-------
SECTION 3
SIC 28213 POLYSTYRENE RESINS AND COPOLYMERS
Polystyrene's excellent combination of physical properties and
ease of processing by injection molding and extrusion make it a unique
thermoplastic. The crystal clear product has excellent thermal and
dimensional stabilities, high flexural and tensile strengths, and good
electrical properties. Rubber-modified types have been developed with
superior impact properties for appliance, packaging, and housewares
markets where abuse resistance is needed. Copolymers containing
acrylonitrile have been marketed for applications, that require im-
proved chemical resistance. Other types for phonograph records, sheets,
and films have been marketed. Very lightweight, rigid foams have been
developed and marketed for use in insulation, packaging of breakable
items, and as molded items where lightweight and buoyancy are desired.
The cost of polystyrene is low.
The past and projected growth of polystyrene production is as
follows:
Production,
Year 109 Ib/yr
1962 1.25
1963 1.50
1965 1.90
1967 , 2.25
1970 3.15
1977 -4.40
I. PROCESSES AND WASTES
A. Fundamental Manufacturing Process
The fundamental manufacturing process for polystyrene resins and
copolymers is a batch process that uses a combination of both bulk
(mass polymerization) and suspension polymerization methods. Styrene
monomer, or mixtures of monomers, is purified by distillation or caustic
washing to remove inhibitors. The purified raw materials, along with
an initiator, are charged into stainless-steel or aluminum polymeriza-
tion vessels. These vessels are jacketed for heating and cooling and
contain agitators. Polymerization of the monomer is carried out at
about 90°C to approximately 30% conversion. At this stage, the reaction
mass is syrupy. During this prepolymerization step in the manufacturing
process, water is used only as a heat-exchange medium. It does not
come into contact with the product and is therefore not contaminated.
This cooling water is recirculated.
28
-------
The prepolymer, or partially polymerized mass, is then transferred
to suspension polymerization reactors containing water and proprietory
suspending and dispersing agents. The reactors are usually jacketed,
stirred stainless-steel vessels and range in size from 1,000 to 5,000
gal. The syrupy mass is broken up into droplets by means of the stirrer
and "held in suspension in the aqueous phase. Temperature is a critical
variable in the further polymerization of the product. After completion
of polymerization, the polymer suspension is sent to a blow-down tank
where any unreacted monomer is stripped. The stripped batch is then
centrifuged, and the polymer product is filtered, washed, and dewatered
(dried). A flow chart for this process is shown in Figure 5.
A few polystyrene producers eliminate the first step in this process
and introduce purified monomer directly into the suspension polymeriza-
tion reactor. Polymerization is thus carried out entirely via suspen-
tion polymerization.
B. Significant Water Wastes
Reaction water (suspension medium) and wash water constitute the
two significant sources of waste water in the production of polystyrene.
Some cooling water is lost due to evaporation, however, the amount lost
is insignificant, compared to the primary sources of water waste.
Approximately 1.5 gal of water other than cooling water is used
for each pound of polymer product produced. The thermal and chemical
pollution of the effluent water is at a low level. This is due to the
small quantities of additives used in suspension polymerization: (a)
catalyst, 0.1 to 0.5% based on weight of monomer; (b) suspending agents,
0.01 to 0.5% based on weight of monomer; and (c) reaction medium tem-
perature, 120 to 180°F. Although specific additives are proprietary,
the catalysts used are generally of the peroxide type. The suspending
agents used are a wide variety. They can be methyl or ethyl cellulose,
polyacrylic acids and their salts, polyvinyl alcohol and numerous
naturally occurring materials such as gelatin, starches, gums, casein,
zein, and alginates. Inorganic materials such as calcium carbonate,
calcium phosphate, talc, clays, and silicates may also be present in
effluent reaction, water. Water vapor is said to be the only air-dis-
charged waste.
C. Reuse of Process Water in 1964
Water used in the suspension polymerization and washing of poly-
styrene polymer is not commonly reused. Water used for cooling is
essentially uncontaminated and is recirculated through cooling towers.
The amount lost due to evaporation constitutes approximately 1%.
D. Industry Subprocess Mix
The fundamental combination bulk-suspension polymerization process
is used for a number of reasons:
29
-------
Styrene Monomer
(Catalyst)
r
Bulk Polymerization
to Syrup Stage
1
~i
Waste
Suspension Polymerization
to Completion
(Suspending,Dispersing Agents)
J
t /
Stripping of Unreacted
Monomer
1
Centrifuging
1
Filtering and Washing
I
Drying
t
Waste
t
Waste
t
Waste
Polystyrene
Figure 5
FLOW CHART FOR POLYSTYRENE PRODUCTION
30
-------
(1.) It is the most economical, since water is used as the sus-
pending medium and as a heat-transfer medium.
(2.) The product obtained is relatively pure and contains only
trace amounts of catalyst and suspending agents, since only
minimal amounts of these additives are used in the polymer-
ization. Thus, purification of the product is usually un-
necessary. Since this process is economical, efficient, and
trouble-free with regard to waste problems, no new technology
is foreseen. The companies interviewed intend to use present
technology in the future. The level of technology therefore
will have little effect on waste water content. However,
since production will be increased over the next ten years,
the volume of waste water, with incorporated wastes, will
increase proportionally.
E. Difficult Waste Control Problems of Subprocesses
There are no subprocesses.
F. Levels of Technology
1. Typical
The combination bulk and suspension process is the typical level
of technology.
2. Older
The present combination bulk-suspension polymerization of poly-
styrene is an outgrowth of the old "bead process." In the bead process,
large monomer drops were suspension polymerized. Since large drops
were used, the process was essentially a bulk polymerization and the
problems associated with bulk polymerization were also inherent, namely,
problems associated with mixing and heat transfer and broadening of
molecular-weight range with subsequent lowering of mechanical proper-
ties. These difficulties were overcome in suspension polymerization by
simply reducing the size of the drop being polymerized. Thus, in
present technology, extremely small droplets of either monomer or pre-
polymer are utilized.
3. Advanced
Of the companies interviewed, only one anticipates converting to
a new process. Details of the process were considered proprietary.
Range of Plant Size, %
Technology Plant Size, Small Medium Large
Level 106 Ib/yr 10-50 50-100 100
Typical 10 to 100 20 30 50
Older None -
Advanced None - - -
31
-------
II. GROSS WASTE QUANTITIES BEFORE TREATMENT OR OTHER DISPOSAL
A. Waste Quantities and Volumes for an Average Size
Plant Producing 50 x 10& Ib/yr
Waste Load, Waste Water Volume,
106 Ib/vr 106 qal/vr
0.5 75
No data could be obtained on the concentration of BOD or SS in waste
water. The above waste load is based on the assumption that 0.5%
suspending agents (based on the weight of product) are being used by
the entire industry. It is possible that some products is lost in the
waste water, but no data are available. A municipal treatment facility
reported that the effluent from one polystyrene plant was entirely
inorganic, indicating that no catalyst or product were present in the
waste. No significant variations in loadings are caused by shift,
daily, or seasonal changes. There are no significant differences in
unit waste production for plants of significantly different production
output.
B. Total Waste Quantities and Waste Water Volumes
Typical Technology
Waste Quantities, Waste Water Volume,
106 Ib/vr 109 gal/vr
23 3.38
C. Total Waste and Waste Water Quantities/Unit of Physical Product
Typical Technology
Waste Load ^ Waste Water Volume
Ib/lb product gal/lb product
0.01 1.5
D. Total Waste Quantities and Waste Water Volumes Produced
in Base Year (1963)
Typical Technology
Waste Load, Waste Water Volume,
10° Ib/vr 109 qal/vr
15.0 23
Based on assumption that 0.01 Ib of waste is produced per Ib
of product (0.5% catalyst plus 0.5% suspending agents)7 also
assuming all of these contaminants are removed from product
and disposed of in waste water and that no product is wasted.
32
-------
E. Projected Gross Wastes and Waste Water Volumes
Typical Technology
Year
1967
1968
1969
1970
1971
1972
1977
Waste Load,
106 Ib/vr
23
25
28
32
33
35
44
Waste
Volume, 10
3.5
3.8
4.2
4.7
5.0
5.3
6.6
Water
gal/yr
F. Seasonal Waste Production Patterns
There are no seasonal patterns in waste production from the
polymerization of styrene-type plastics.
III. WASTE REDUCTION PRACTICES
A. Processing Practices
There are no processing practices associated with waste
reduction.
B. Treatment Practices
1. Normal Removal Efficiency (%) of Waste Treatment
Methods in a Plant Employing Typical Technology
No plants employing typical technology have waste treatment
facilities.
2. Rate of Adoption of Waste Treatment Practices
Treatment has been and will continue to be discharged to municipal
sewers at a rate exceeding 90%
(a) There are no sequential application or removal
techniques required by technological considerations.
(b) There are no substitute techniques in use.
(c) There are no interdependencies among waste removal
techniques that affect costs or relative efficiencies.
33
-------
3. Combined Wastes
a. Percentage of Waste Discharged to Municipal Sewers
It is estimated that over 9094 of the waste is discharged
to municipal sewers.
b. Waste Removal Problems Caused by Combining
Industrial with Municipal Wastes
Municipal water departments contacted in regard to problems they
encounter with waste waters from the processing of polystyrene claim
that to date no problems have arisen. Combination of this waste
water with municipal wastes is feasible without alteration of existing
treatment processes.
C. By-product Utilization
There are no by-product for wastes derived from the polymerization
of polystyrene, and none is likely to be developed by 1977.
D. Base Year Net Waste Quantities
It is estimated that 15 x 10 Ib of waste were discharged to
municipal sewers in 1963. No accurate data on net amounts discharged,
if any, to watercourses are available. At 87% for this particular
type of waste, it can be estimated that 2 x 106 of waste reach the
watercourse.
E. Projected Net Waste Quantities
No accurate data are available. It can be assumed that most of
the waste will be discharged to municipal systems. Assuming that
87% removal will hold constant, the following net waste quantities
can be estimated.
Net Waste
Quantities
Year 106 Ib/yr
1967 3.0
1968 3.3
1969 3.6
1970 4.2
1971 4.3
1972 4.6
1977 5.7
34
-------
IV. WASTE REDUCTION OR REMOVAL COST INFORMATION
A. Replacement Value and Annual Operating and Maintenance
Expenditures of Existing Waste Removal Facilities
Polystyrene plants studied* do not have waste removal facilities,
B. Capital Cost and Economic Life of Processing and
Waste Removal Treatment Equipment
There are no waste removal treatment facilities.
The plants studied produce 80% of the polystyrene
manufactured in the United States.
35
-------
SECTION 4
SIC 28214 POLYOLEFINS
POLYETHYLENE
The polyethylenes produced today run the gamut from low-molecular-
weight waxes of a few thousand-molecular-weight to polethylenes of
several-million-molecular weight. In addition to the range in molecular
weights, an equally wide range in stiffness is available. Product
versatility is further obtained by synthesizing copolymers with hydro-
carbons or polar monomers. To these qualities must be added low-cost,
easy processability, good stability in processing, low permeability to
water, good electrical properties, and wide range of property modifica-
tion for specific processing or end use requirements. It is not un-
common for a producer to market more than 50 grades. In decreasing
order of utilization polyethylene is used: film and sheet, injection
molding, blow-molded bottles, cable insulation, coatings, pipe, and
all other uses.
The past and project growth of polyethylene is as follows:
Production
109 Ib/vr
1.85
2.08
3.03
3.59
4.95
7.60
I. PROCESSES AND WASTES
A. Fundamental Manufacturing Process
A fundamental process for manufacturing polyethylene is the high-
pressure method.* For convenience, the final product is often referred
to as low-density polyethlene (LDPE). This form of synthesis is an
example of continuous-flow gas-phase bulk, polymerization.** The high-
purity (99.9%) ethylene stream is elevated to a process pressure and
passed through a reactor in the presence of free radical initiators.
*For uniformity among manufacturers, the final product is defined
by ASTM tests D151 or D792; Type I has a density between 0.914 and
0.925, Type II between 0.926 and 0.940
** Relatively small volumes of LDPE for specialty applications are
commercially produced by solution and emulsion processes.
36
-------
The resulting polymer-monomer mixture is seperated by pressure reduction
into a monomer-rich stream and a polymer-rich stream. The monomer-rich
stream can be cleaned and recyled as feed to the reactor or used in
another process. The polymer-rich stream is usually further concen-
trated by a second separation step and then extruded into ribbons
or strands for pelletizing.
The reactor can be of a tubular or an autoclave design. Figures
6 and 7 are the flow charts for these processes. The tubular reactor
operates at 150 to 300°C between 14,000 and 40,000 psig* at the charge
end and as low as 10,000 psig at the discharge end. The physical
properties of the final product are a function of reaction temperature,
pressure, equipment, and initiator or initiators. The autoclave poly-
merizes in minutes rather than seconds at a pressure between 15,000
and 30,000 psig. Modifiers can be added directly to the reactor or may
be added to the feed stream before compression. Chain transfer agents,
diluents, retarders, or accelerators can also be metered into the feed
stream in an effort to modify reaction kinetics and polymer properties.
The reaction mass at the end of the tube passes through a let-down
valve into a product separator from which the polyethylene is removed,
water-cooled, and chopped. The unreacted ethylene is cleaned, cooled,
and recycled.
The high-pressure process can produce copolymers with polar
materials, such as acrylates, as well as copolymers with olefins.
Another fundamental process for making polyethylene is the low-
pressure method. The reaction product is referred to as linear, or
high-density, polyethylene (HOPE).** The most common reaction is
known as the Phillips process, which uses a supported catalyst
(chromia-alumina combinations) . A flow chart is shown in Figure 8.
The reaction takes place in a low-pressure, agitated vessel between
135 and 190°C. The process utilizes solvent that must be separated
and purified.
The other low-pressure method for synthesizing linear, or HDPE, is
known as the Ziegler process (see Figure 9). The converter reactor'and
operating conditions are very similar to that of the Phillips process.
The Ziegler process utilizes titanium halides? and aluminum is used
for catalysis.
The separation and purification of the solvent requires more
sophisticated equipment than the Phillips process. In most respects
the two processes and products are very similar.
"* Units have been operated between 9,000 and 70,000 psig.
** Linear polyethylene comes in densities between 0.940 and 0.970.
Copolymers can be synthesized with other olefins.
37
-------
Vent
i
Filter
Oils
Waxes
Ethylene
Feed Stock
i
Low Pressure
Purnp
High Pressure
Pump
i
Tubular Reactor
i
Separator
i
Deodorizer
I
Chiller
i
Chopper
i
Polyethylene
Catalyst
Figure 6
TUBULAR-REACTOR PROCESS FOR LOW DENSITY POLYETHYLENE PRODUCTION
38
-------
Ethylene
Feed
i
Low Pressure
Pump
i f
High Pressure
Pump
Oils
Waxes
i
Filter
Mixer
Autoclave
Reactor
I
Separator
\f
Chiller-
Chopper
1
Polyethylene
Catalyst
Figure 7
AUTOCLAVE-REACTOR PROCESS FOR LOW DENSITY POLYETHYLENE PRODUCTION
39
287-033 O - 68 - 4
-------
Ethylene
Feed Stock Catalyst
Solvent
LLE
Reactor
1
Separator
i
Filter
Spent
Catalyst
Alcohol
< r \'
i
Precipitator
Centrifuge
I
Dryer
i
Polyethylene
Solvent
Separation
and
Purification
Figure B
PHILLIPS PROCESS FOR HIGH DENSITY POLYETHYLENE PRODUCTION
40
-------
Catalyst
Mixing Tank
Sequestering
Agent
Water or
Alcohol
Dry Hydrocarbon Solvent
Transition Metal Halide
Aluminum Alkyl
Catalyst Modifier
(optional)
Dry Hydrocarbon Solvent
Reactor
1
Flash
Separator
Staged
Washer
Centrifuge
Dryer
I
Polyethylene
Ethylene
Feed Stock
Alcohol Waste
Solvent
Figure 9
ZIEGLER PROCESS FOR HIGH DENSITY POLYETHYLENE PRODUCTION
41
-------
B. Significant Water Wastes
Low-density polyethylene (LDPE) processes create no significant
water wastes. Water contacts the product only at the chiller-chopper
step. An analysis of a typical highly recirculated chill water (ribbon
bath) revealed a very low total organic carbon (TOG) of 0.4 mg/liter.
The heat generation depends upon pressure, initiator concentration,
and temperature. If the total conversion of ethylene were run
adiabatically, the product temperature would be 1000°C hotter than the
starting temperature. Heat is removed by loss through the tube walls
and by removal through recycling of the gas and the product. These
are properly balanced to give a stable system. As defined by current
interpretation of legislation, thermal pollution is not a problem
in polyethylene polymerization.
Air pollution is generated by the combustion of ethylene (flare
gasses) that has been collected from accidental losses, valves, pumps,
and fittings. Some plants burn solids wastes for power generation.
The high-density polyethylene (HDPE) processes, Phillips and
Ziegler, produce no significant water wastes. Typical effluent process
waste waters contain a BOD in the range of less than 10 mg/liter.
Potential hazards for generation of waterborne wastes are improper
operation, spills, and washdown of equipment and facilities.
Air-discharged wastes are generated from burning ethylene flare gas.
C. Reuse of Process Water in 1964
Water is used for chilling the final product (LDPE) at the time
it is pelletized by dicers, choppers, or cube cutters.. Alternately, die
face cutters can be used to cut the molten polymer prior to chilling it.
The volume of ^ater utilized for this operation is insignificant,
4 x 10^ gal/yr for the entire LDPE industry.
It is customary to reuse the chill water with only minor makeup.
The water is reused several hundred times. Because of the low volume
involved, no accurate calculations have been made of this reuse.
Linear polyethylene (HDPE) uses approximately 150 x 10 gal/yr for
process water. * In a typical operation water is not reused.
* A typical plant manufacturing 140 x 106 Ib/yr of LDPE utilizes 200
gpm of chill water with 2% makeup. By assuming a total,annual
production of 2.9 x 10y Ib of LDPE, we arrive at 4 x 10 gal/yr of
process chill water.
** Calculations are based upon 1.05 x 106 Ib HDPE produced per year;
process water utilized at a rate of 144,000 gal per 10 Ib of
HDPE produced.
42
-------
D. industry Subprocess Mix*
Estimated Percentage of
Production from jProcess
High-Pressure Low Pressure
Year Process Process
1950 100 0
1963 78 22
1967 73 27
1972 70 30
1977 70 30
E. Difficult Waste Control Problems o£ Subprocesses
The volume of process water used and waste loads for fundamental
processes and subprocesses and relatively insignificant. The variance
found in waste loads between processes and between processes and sub-
processes are relatively insignificant.
F. Levels of Technology
(1) Typical production processes are describred in Section IA.
(2) Older production processes are the same as the typical
technology.
(3) No advanced technology is forseen.
Plant size **
, Plants __%
Small (50 x 10 Ib/yr) 12 39
Medium (50-100 x 106 Ib/yr) 11 35
Large (100 x 106 Ib/yr) 8 26
II. GROSS WASTE QUANTITIES BEFORE TREATMENT OR OTHER DISPOSAL
A. Waste Quantities and Volumes for an Average Sized Plant
of 140 x 10b Ib/yr of LDPE; and Average Sized Plant of
100 x 106 Ib/yr of HOPE
The waste load for LDPE is insignificant and is too low for
practical measurement.
*Data are interpolated and extrapolated from production data in pounds
for years 1955, 1960, 1965, 1967, 1970, and 1975 from Plastics
World, page 26, Jan. 1967.
** Chemical Profiles, 1 January 1965.
43
-------
The waste water volume for LDPE is insignificant. There is
no measurable flow.
A waste load of 12,000 Ib BOD/yr is insignificant for HDPE.
A waste water volume of 144 x 10 gal/yr is insignificant
for HDPE.
B. Total Waste Quantities and Waste Water Volumes
Waste load and waste water volume are insignificant for LDPE
and HDPE.
C. Total Waste and Waste Water Quantities per Unit
of Physical Product
Waste load and waste water volume are insignificant for LDPE
and HDPE.
D. Total Waste Quantities and Waste Water Volumes
Produced in Base Year 1S63
Waste load and waste water volume were insignificant for LDPE and
HDPE.
E. Projected Gross Wastes and Waste Water Volumes
For both LDPE and HDPE, -the waste load and waste water volumes are
considered negligible for the years 1968 through 1977.
F. Seasonal Waste Production Patterns
There are no significant seasonal patterns in waste production.
Ill . WASTE REDUCTION PRACTICES
A. Processing Practices
i_._ Waste Reduction Efficiency (%) of a Given Sub process
Relative to Alternative Sub processes
This is not applicable to polyethylene production.
44
-------
2. Sequential Requirements and Intedependencies of
Processes Affecting Waste Production
This is not applicable to ethylene production.
B. ^Treatment Practices
Waste loads and waste water volumes for LDPE and HDPE are so low
that they do not require treatment. It is not expected that this
condition will change in the future.
C. By-product Utilization
There are no by-products.
D. Base Year Net Waste Quantities
Base year net waste quantities were insignificant.
E. Projected Net Waste Quantities
Net waste in the future will be insignificant.
IV. WASTE REDUCTION OR REMOVAL COST INFORMATION
A. Replacement Value and Annual Operating and Maintenance
Expenditures of Existing Waste Removal Facilities (1966)
Waste loads and waste water volumes are such that they do not
require treatment for LDPE and HDPE.
B. Capital Cost and Economic Life of Processing and Waste
Removal Treatment Equipment
Waste loads and waste water volumes are such that they do not require
treatment for LDPE and HDPE. There are no reductions in processing
costs due to modified technology or by-product recovery.
Source Material: "Manufacture of Plastics," Vol. 1, W. Mayo Smith,
Reinhold Publ. Corp., 1964.
"Polyethylene," R. A. Raff & J. B. Allison,
Koppers Co., Inc., Interscience Publishers, 1956.
45
-------
"Market Study of the Plastics Industry," R.
Kirkconnell, 1963. Majority of data obtained
by interviews, plant inspections, telephone
communications, and in-house experience.
46
-------
POLYPROPYLENE
Polypropylene is attractive for many uses because of its unique
combination of desirable properties and low cost. These qualities make
this polymer valuable in various molding and extrusion applications;
special grades are also available for manufacture of film and fiber.
It is amenable to use in injection-molding, blow-molding, and extrusion.
High melting point and heat resistance go hand in hand to produce molded
articles that withstand boiling and autoclaving, but have useful strength
at elevated temperatures. Good machinability permits threading and/or
the cutting operations on molded pieces. Its use for bread wrap and
similar food-packaging applications is made possible by its non-toxic
nature, low extractibles, and amenability to protection by stabilizers
safe for food use. Polypropylene fiber and filament take advantage of
the relatively high melting temperature and the high tensile strength
that results when propylene is stretched. The polymer has found early
use in pipe and sheet.
The pasts and projected growth of polypropylene reflects the
management of desirable physical properties with low cost.
Production
109 Ib/yr
0.15
0.20
0.37
0.76
0.90
1.50
I. PROCESSES AND WASTE
A. Fundamental Manufacturing Process
The fundamental process for producing polypropylene involves
polymerization, purification, and finishing. During polymerization, a
solution of propylene in an iner^ hydro carbon diluent is converted to
a slurry containing insoluble, crystalline and noncrystalline polymer of
high molecular weight. The noncrystalline polypropylene formed in the
process, along with catalyst and diluent, is separated from the
crystalline product during purification. The dried powder is then
compound for specific end uses, pelletized, and packaged for shipment.
During polymerization, complete conversion of propylene per pass
is not economically desirable. A fraction of the propylene must
therefore be recycled. Certain impurities tend to accumulate and must
be removed. Propane gradually builds up and must be distilled out.
47
-------
Propylene
Catalyst
Wash
Diluent
Conti nuous
Polymer!zer
±
Flash Tank
Surge Drum
Centrifuge
n
Diluent
Cleanup
1
Dryer
Extruder
I
Dicer
I
Polypropylene
Figure 10
CONTINUOUS PROCESS FOR POLYPROPYLENE PRODUCTION
48
-------
Polar materials used in the purification steps must "be completely
removed by distillation and/or suitable scrubbers or absorbers.
Hydrocarbon diluent, which tends to be carried out with the propylene,
may have to be removed, depending upon the process.
The process for the synthesis, purification, and finishing of
polypropylene is a secret closely guarded by all manufacturers. However,
well-recognized basic requirements and steps in the process have been
published ana can be taken as typical of existing conditions. The
polymerization step may be either batch or continuous, both are in use.
Figure 10 is a flow chart for the continuous process. The reaction takes
place in vessels able to withstand 200 psig. Polymerization is exothemic
(1000 BTU/lb of polymer) . A part of the heat may be dissipated by cold
incoming nionomer and solvent in the continuous operation. Other methods
of heat removal include jacket cooling, reflux condensers and re-
circulation of cool slurry.
B. Significant Water Wastes
The synthesis of high-density polyethylene (HDPE) and polypropylene
presents very similar processes, waste loads, and waste water volumes.
In both cases, the loads and volumes present almost negligible problems
relative to treatments and costs.
49
-------
SECTION 5
SIC 28215 ACRYLICS
The acrylic monomers are mainly used in the preparation of polymers
and copolymers of increasingly broad application. Several producers
make cast sheet. The volume has increased with price reduction. During
the past few years, the production of emulsion products (paints) has
increased sharply.
The acrylic monomers are commercially polymerized by a free radical
process.
Production,
Year 109 Ib/yr
1962 0.18
1963 0.20
1965 0.24
1967 0.29
1970 0.37
1977 0.52
I. PROCESS AND WASTES
A. Fundamental Manufacturing Process
Acrylic resins are made by three processes: bulk polymerization,
solution polymerization, and emulsion polymerization. Bulk polymeriza-
tion is used for cast sheets and molding and extruding powders. Solu-
tion polymerization is used for industrial sales coatings including
automobile paints and fabric coatings. Emulsion polymerization is used
mainly for trade sales coatings such as home paints. A good estimate
is that about 40% of acrylic resins are made by emulsion polymerization,
Emulsion polymerization of acrylic resins is a batch operation.
The monomer is combined with the catalyst, water, and surfactant in
a large vat. Polymerization and emulsification are carried out
simultaneously. Some of the water is removed and additional surfactant
added. Lumps are removed by either filtration or centrifugation, and
the emulsion is placed into .storage. The final product contains about
50% acrylic resin. This process is a batch process, and efficient
operation requires vats that are no smaller than 1000 gal. A maximum
size of 4000 gal results from a need to control the progress of the
polymerization and remove the heat of reaction.
Figure 11 is a flow diagram of the emulsion process.
50
-------
Monomer A, Monomer B,
Catalyst, Surfactant,
Water
I
Polymerization
and Emulsification
i
Post Addition
of Surfactant
i
Filtration
Acrylic
Emulsion
i
Lumps
Wash
Water
I
Waste
Monomer
Polymer
Surfactant
Figure 11
FLOW DIAGRAM FOR THE PRODUCTION OF ACRYLIC EMULSION
51
-------
B. Significant Water Wastes
1. Emulsion Process
The bulk and solution polymerization methods create very little
wastes. Waste from the manufacture of acrylic resins is virtually all
from emulsion polymerization. The emulsion polymerization process will
be considered the fundamental process since waste is the main concern
in this study.
The emulsion polymerization of acrylates creates a concentrated
water waste. The waste in the process comes from washing the vat be-
tween batches and from lumps that are filtered or centrifuged out of
the emulsion mix. Thus the. waste contains acrylic monomer, acrylic
polymer, emulsifying agents, and catalyst.
The waste is white and highly turbid and has a high suspended-
solids content.
2. Other Acrylic Processes
There is no known process water involved in the polymerization of
acrylates by the other two processes.
C. Reuse of Process Water in 1964
There is no reuse of process water.
D. Industry Subprocess Mix
There is some subprocess mix by those who make acrylic emulsions.
Both the products of the emulsion process and the solution process are
mainly directed towards the coatings market. Thus the manufacturer of
emulsions very often has a solution acrylic product as well. Usually
less than 20% of the acrylic volume is the solution type. The product
mix also includes a number of other coating products so that very little
of the total combined waste is due to the manufacturer of acrylic resins.
E. Difficult Waste Control Problem of Subprocesses
Very little waste is created by the subprocesses. There are no
difficult waste control problems from them.
F« Levels pjE Technology
1. Typical
All three methods — emulsion, solution, and bulk — must be con-
sidered typical methods for making acrylic resins. Since the uses are
52
-------
different, they are not competing for the same market, and the pro-
duction in one area does not affect the market in another. Jointly,
they affect one another only in the demand for the monomer.
Older
The oldest process is the bulk polymerization process, but the
demand for the bulk material has not been affected by the markets
for the other two types of acrylic resins.
3. Advanced
An advanced type of acrylic resin has been developed recently.
It is called a syrup and consists of a solution of polymer in the
monomer. It has special advantages in bulk-type applications, i.e.,
for making sheets and complicated solid shapes. Its waste should be
little different from that of the bulk-type operation. Perhaps the
ease in its use will improve the market for the bulk resin. This
technology is considered proprietary; consequently, accurate projec-
tions cannot be made.
No reliable data are available for the range of plant sizes and
outputs.
II. GROSS WASTE QUANTITIES BEFORE TREATMENT OR OTHER DISPOSAL
A. Waste Quantities and Volumes for One Plant Current Technology -
Medium Sized Plant
Waste Load, Waste Water Volume,
106 Ib BQD/yr 109 gal/yr
Emulsion 0.030 0.0025
( 20 x 106 Ib/yr)
There is no significant difference in unit waste production for
plants of significantly different production output.
B. Total Waste Quantities and Waste Water Volumes
Waste Load, Waste Water Volume,
106 Ig BOD/yr 1Q9 gal/yr
Emulsion 0.165 0.014
53
-------
C. Total Waste and Waste Water Quantities per Unit of Physical
Product
Waste Load, Waste Water Volume,
Ib BCD/lb Prod qal/lb
Emulsion 0.0015 0.125
D. Total Waste Quantities and Waste Water Volumes Produced in Base
Year 1963
Waste Loac, Waste Water Volume,
10° Ib BCD/yr 109 gal/yr
Emulsion 0.120 0.010
E. Projected Gross Wastes and Waste Water Volumes
Emulsion Polymerization
Waste Load,
Year 106 Ib BOD/yr
1968 0.192
1969 0.204
1970 0.222
1971 0.234
1972 0.252
1977 0.312
F. Seasonal Waste Production Patterns
For most manufacturers of acrylic resins, a seasonal pattern does
not exist. For the emulsion manufacturer directly tied into trade sales
of paint, the manufacturer leads the trade sale by 60 days. The fall
and winter months are the slowest for paints; demand may drop as much
as 30% during these months.
The amount of the acrylic resins being used for latex paints is
somewhat less than 4036 of the total resin output. The amount of future
seasonal changes will depend on the demand for acrylic latex paints.
Although the paint is easy to apply and weathers well, it is expensive.
III. WASTE REDUCTION PRACTICES
A. Process Practices
1. Waste Reduction Efficiency (%) of a Given Subprocess Relative
to Alternative Subprocesses
Although still an undisclosed quantity, the wastes related to the
bulk process and to the solution process are reputed to be insignificant,
54
-------
compared to the waste from the emulsion process. Comparisons between
subprocesses are invalid, however, since the products do not compete
with each other for the same end use.
2. Sequential Requirements and Interdependencies of Processes
Affecting Waste Production
An accurate answer to this question cannot be given at this time.
B. Treatment Practices
1. Normal Removal Efficiency (%) of Waste Treatment Methods
in Treating Waste from a Plant of Typical Technology
Acrylic plants, unlike cellulosic plants, are in a complex of
facilities that make a number of different products with a corresponding
variety of wastes. Also, the acrylic plants generally feed their waste
into municipal systems. This has created a number of problems from the
start and a variety of eventual solutions. These solutions range from
a self-contained closed-end waste treatment plant in which the water is
continuously recycled to a wash water treatment plant that also treats
the waste for a municipality in a joint operation.
A particular plant, where some waste removal efficiency data were
available, uses activated sludge. The removal efficiency of BOD is
85%. Suspended solids removal was estimated to be at about the same
level.
2. Rate of Adoption of Waste Treatment Practices
No concrete data of this type were available, but it is apparent
that everyone either had a treatment facility or was about to install
a treatment facility that would meet the requirements of the present
local code.
3. Percentage of Waste Discharged to Municipal Sewers
No data of this type were available.
4. Waste Removal Problems Caused by Combining Industrial
Waste with Municipal Wastes
The waste is white, highly turbid and has a high suspended solid
content. By nature, the waste requires a particularly long biodegrada-
tion time. A 14 to 20 day treatment is being used in one plant. In
another plant the suspended solids are passed directly into a settling
pond where they are precipitated with fly ash generated in the heating
plant. This process does not take care of all of the fly ash, but it
seems to be the solution to the suspended solids problem.
The waste is better treated at the plant to remove the suspended
solids before passing the effluent out into a municipal system. Some
municipal plants have reported these wastes as essentially untreated
under standard operating conditions.
55
287-033 O - 68 - 5
-------
C. By-product Utilization
There are no by-product uses of wastes not is there a likelihood
of any being developed and marketed in the next ten years.
D. Base Year Net Waste Quantities
No data are available that would permit calculation of net waste
quantities reaching watercourses in 1963. They are no greater than the
gross quantities and probably no less than 10% of those figures.
E. Projected Net Waste Quantities
No data are available to permit calculations of projected net
waste quantities.
IV. WASTE REDUCTION OR REMOVAL COST INFORMATION
A. Replacement Value and Annual Operating and Maintenance
Expenditures of Existing Waste Removal Facilities (1966)
Data in this specific format (replacement value) were not available.
The following figures give some indication of treatment costs.
Emulsion produced 0.0037 §/lb Product (Emulsion)
Total acrylics produced 38 x 10^ $/yr
Capital goods depreciation 33 x 10;? $/yr
Operating and maintenance 5 x 103 $/yr
B. Capital Cost and Economic Life of Processing and Waste Removal
Treatment Equipment
Capital Depreciation, Economic
$/lb product Life, yr
Emulsion 3 x 10~4 40
Capital goods cost for total acrylics produced* = $1.3 x 10 .
* Total waste comes from the production of acrylic emulsion.
56
-------
SECTION 6
SIC 28216 ALKYD AND POLYESTER RESINS
Alkyds 'and polyesters are characterized by great variation in
formulations, not only as represented by the class of resin produced,
such as oil-modified polyesters (alkyds), unsaturated polyesters
(laminates and molding compounds), and linear polyesters (films and
fibers) , but also within each group. For example, one plant engaged
solely in the production of alkyd resins had 300 different compositions
in active manufacturing status. Saturated polyesters are used for
urethane plastic production. Highly branched polyesters are used for
urethane polymers for coatings, rigid foams, and adhesives.
Many of the applications for polyesters require a cross-linking
(curing) process that is difficult to control and does not lend itself
to mass production; the anticipated growth rate reflects some of these
processing characteristics.
Production,
109 Ib/yr
0.68
0.76
0.92
1.10
1.40
1.80
I. PROCESSES AND WASTES
A. Fundamental Manufacturing Process
The fundamental manufacturing process for alkyd and polyester
resins is batch-type condensation polymerization of a dibasic acid and
a polyfunctional alcohol. Polymerization in the presence of oils or
fatty acids results in a complicated polymar known as an alkyd resin.
The polymerization process is illustrated in Figure 12. Two types
of polyester resins can be identified. One consists of an unsaturated
polyester to which a monomer is added, e.g., styrene, resulting in
thermosetting properties due to copolymerization. The other, a simpler
polymer, consists of linear chains with no provision for cross-linking.
In each case the raw materials are heated to the reaction temperature
(165 to 260°C) ani the degree of polymerization is monitored by
viscosity or acid number.
57
-------
B. Significant Water Wastes
The significant wastes associated with the production of alkyd and
polyester resins are (1) unreacted volatile fractions of raw materials
that either appear in the withdrawn water of esterification and in the
water used in scrubbers, or are vented to the atmosphere, and (2)
residue in kettles cleaned out either with caustic solutions or
solvents.
C. Reuse of Process Water in 1964
In the representative segment of the industry studied, no signif-
icant amount of process water is reused.
D. Industry Subprocess Mix
No subprocesses in the polymerization of alkyds and polyesters
were encountered. Production technology has been stable, and the
consensus is that it will remain so.
E. Difficult Waste Control Problems
The variation in the attitude of the plant toward the difficulty
of waster control is illustrated by the differences in waste water
treatment practices. These practices vary from no treatment to
complete segregation and shipping out of all process waste water in
tank trucks for land disposal since no treatment facilities exist.
F. Levels of Technology
No distinction between levels of technology could be identified.
Plants range in size from 1 to 30 million Ib/yr. No estimate of
percentages of small, medium, and large plants is available.
II. GROSS WASTE QUANTITIES BEFORE TREATMENT OR OTHER
DISPOSAL
A. Waste Quantities and Volumes for an Average Size
Plant Producinct 10 x 10" Ib/yr
Production 10 x 106 Ib/yr
Waste load 55 x 103 Ib/yr
5
Waste water volume 20 x 10 gal/yr
58
-------
Polyol
Fatty Acid
Dibasic Acid
Polyol
Dibasic Acid
Crosslinkers,
Additives
Polymerization to
Unsaturated
Polyester
Formulation
of Resins
\
Water Waste
FLOW CHART FOR ALKYD PRODUCTION
Monomer
Additives
^
Polymerization to
Un saturated
Polyester
Formulation of
Resins
Alkyd Resins
Polyester Resin
Water Waste
Figure 12
FLOW CHART FOR POLYESTER PRODUCTION
-------
The waste load is predominately solvent or caustic kettle residue
cleaning solution. Unit waste production does not vary significantly
for plants of substantially different production output.
Waste water volume can vary considerably, however, depending on
whether scrubbers are used to control vapors from the process. The
above table assumes the use of scrubbers.
Loading is of course sporadic since a batch process is involved
and washout is the significant source of waste. Variation in loading
on a time scale greater than a day, however, is not encountered.
B. Total Waste Quantities and Waste Water Volumes
Waste load 6.6 x 106 Ib/yr
Q
Waste water volume 2.3 x 10 gal/yr
C. Total Waste and Waste Water Quantities per Unit of
Physical Product
Waste load 0.006 Ib/lb product
Waste water volume 2.0 gal/lb product
D. Total Waste Quantities and Waste Water Volumes Produced
in Base Year 1963
Waste load 4.6 x 10 Ib/yr
G
Waste water volume 1.52 x 10 gal/yr
E. Projected Gross Waste and Waste Water Volumes
Year
1968
1969
1970
1S71
1972
Waste
Load,
106 lb
7.5
7.8
8.4
8.7
9.0
Waste
Water ,
10? qal
2.5
2.6
2.8
2.9
3.0
1977 10.8 3.6
This projection is based on production data for the years 1962
to 1967 and on the estimated growth rate.
60
-------
F. Seasonal Waste Production Patterns
There are no significant seasonal patterns in waste production.
III. WASTE REDUCTION PRACTICES
A. Processing Practices
1. Waste Reduction Efficiency (%) of a Given Subprocess Relative
to Alternative Subprocesses
There are no subprocesses.
2. Sequential Requirements and Intejrdejgendencies of Processes
Affecting Waste Production
There are no sequential requirements or interdependences.
B. Treatment j>r a et ice s^
Three degrees of treatment are practiced.
j^. jjo Treatment
A small plant of relatively low production volume may discharge
process water directly into the watercourse, perhaps through a leaking
bed. Some plants discharge into municipal systems.
2. Nominal Treatment
Large plants isolate process water and put it through step tanks
Where oils, etc. are removed by flotation and a solvent isolation process
where some solvent is recovered for reuse. The effectiveness of these
treatment processes is not known, but it is unlikely to be high.
3. Land Disposal
One plant, rather than treat process water, collected it in tank
trucks and hauled it away for land disposal. It is maintained here
that no adequate treatment process exists for waste water from polyester
production. This method is undoubtedly effective in reducing the waste
load in the plant effluent, but the ultimate history of the disposed
waste is not known.
4. Rate of Adoption of Waste Treatment Practices
No data were available. Some plants indicated installation of vapor
control in the early 1960s. The extent to which this has affected water
pollution is unknown.
61
-------
5. Combined Wastes
a. Percentage of Wastes Discharged into Municipal Sewers
Approximately 50% of the waste load is discharged to municipal
sewers.
b. Waste Removal Problems Caused by Combining Industrial
with Municipal Wastes
There are no problems that have been attributed to this waste.
C. By-product Utilization
No by-products are utilized to reduce waste loads. Solvents are
partially removed from wastes for reuse, thus reducing the waste load.
Development of new by-products is unlikely.
D. Base Year Net Waste Quantities
Estimated net waste quantitites reaching watercourses in 1963 is
3 x 106 Ib.
E. Projected Net Waste Quantitites
No data are available.
IV. WASTE REDUCTION OR REMOVAL COST INFORMATION
A. Replacement Value and Annual Operating and Maintenance Expenditures
of Existing Waste Removal Facilities (1966)
Treatment cost* 181 x 10^ $/yr
Capital goods depreciation 8 x 10^ $/yr
Operating and maintenance 18 x 10 $/yr
No one interviewed or visited used any other treatment method, and
the above were found only in plants with relatively large production.
Unit cost would undoubtedly be higher in a smaller plant.
* Sewer charges for 1.1 x 109 gal/yr at $113/106 gal; primary treatment
for 132 x 106 Ib product at 2 x 10~4 $/lb product; and 7.7 x 10° Ib
product at 4 x 10~3 $/lb product for land disposal.
62
-------
B. Capital Cost and Economic Life of Processing and Waste Removal
Treatment Equipment
Capital goods cost* $8 x 10
Economic life 20 yr
There are no reductions in processing costs due to modified
technology or by-product recovery.
* Sewer charges for 1.1 x 10y gal/yr at $113/10G gal; primary treatment
for 132 x 106 Ib product at 2 x 10~4 $/!*> product; and 7.7 x 10° Ib
product at 4 x 10~3 $/lb product for land disposal.
63
-------
SECTION 7
SIC 28217 UREA AND MELAMINE RESINS
Urea and melamine resins which can be used interchangeably, compete
with phenolics. Quality and economic considerations dictate the choice.
The products are water white, allowing pastel shades for items requiring
aesthetic qualities. Their superior tensile and modulus command a higher
price over phenolics. Their electrical properties are outstanding.
These products can be manufactured interchangeably in phenolic process
equipment. In some cases, water treatment charges overlap.
A modest growth rate is reflect in the following:
Production,
Year 10^ Ib/vr
1962 0.49
1963 0.51
1965 0.59
1967 0.66
1970 0.74
1977 0.95
I. PROCESSES AND WASTES
A. Fundamental Manufacturing Process
The fundamental manufacturing process for urea and melamine resins
is a batch condensation polymerization of the urea or melamine with
formalin, a 40% solution of formaldehyde in water. The raw materials,
urea or melamine and formalin, together with catalysts, miscellaneous
additives, and modifiers of a proprietary nature, are charged into a
jacketed reaction vessel and heated to initiate the reaction. Once
initiated, the reaction is exothermic, and the heating steam is shut
off. Cooling water is introduced into the jacket to control the reaction
temperature. The mixture is refluxed until the proper degree of polymer-
ization is reached. The resin is soluble in water so no separation occurs
as in the case of phenolics-formaldehyde condensation resins. The urea
and melamine resins are vacuum-dehydrated until the solids content is
50 to 60% and either sold as a solution or sprayed-dried and sold as a
solid product. At the present time the market demand is 70% for the
spray-dried product and 30% for the solution (60% solids).
Flow diagrams for the manufacturing processes are shown in Figures
13 and 14.
64
-------
75 Ib Urea
188 Ib Formalin
Catalysts
i /
Reactor
i
100 Ib
Urea Resin
1
0)
w
c
-------
52 Ib Melamine
182 Ib Formalin
Catalysts
Reactor
i
100 Ib
Melamine Resin
a)
w
c
0)
TJ
C
8
Waste Water
109 Ib H2O from Formalin
21 Ib H2O of reaction
2 Ib Melamine (66% N2)
2 Ib Formaldehyde
Figure 14
FLOW CHART FOR PRODUCTION OF
MELAMINE-FORMALDEtra>E RESIN
66
-------
B. Significant Water Wastes
The significant water wastes from the production of urea and
melamine resins are: water introduced with the raw materials, (2)
water formed as a product of the condensation reaction, (3) caustic
solutions used for cleaning the reaction kettles, and (4) blowdown fo
from cooling towers. The first three wastes are termed process water,
and the fourth is a portion of the cooling water required to control the
reaction temperature.
From Figure 13, the volumes of these waste waters can be estimated.
Per 100 Ib of dry urea, 10.8 gal of process water is sewered, excluding
the caustic cleaning solution. The cleaning solution is required only
when the formulation per kettle is altered significantly. A reasonable
estimate of usage, prorated over a year's production is 0.01 gal of a
2% sodium hydroxide solution per 100 Ib of resin. About 240 gal of
cooling water is required to control the reaction temperature. Of this
amount, 17 gal is discharged to the sewers as cooling tower blowdown.
Per 100 Ibs of dry melamine, 7.7 gal of process water is sewered,
excluding the caustic cleaning solution. Cleaning solution requirements
and cooling water needs are similar to the urea resins.
The waste water discharged from resin plants has a temperature of
about 85 to 90°F. Thus, thermal pollution is not a problem.
Spray-drying of the resin solution can result in an air pollution
problem. Generally, gas-fired driers are used, and the resin is dried
by contact with heated air. The pollution, therefore, consists of
constituents present in the fuel and small solids of product that are
entrained in the air and carried out to the atmosphere.
C. Reuse of Process Water in 1964
Process water was not reused in 1964.
D. Industry subprocess Mix
Condensation polymerization is the only process used for producing
urea and melamine resin. Production technology has changed little over
the past 20 years, and no new "advanced" technology is foreseen. The
level of technology has little effect on the waste water volumes and
content.
If the resins were completely dehydrated by vacuum distillation,
the process water discharged would increase by 7.9 gal per 100 Ib of
dry product.
E. Difficult Waste Control Problems of Subprocesses
There are no subprocesses.
67
-------
F. Levels of Technology
The batch condensation polymerization technology is representative
of "typical," "older," and "newer" subprocesses. No data are available
on the proportion of small, medium, or large plants.
II. GROSS WASTE QUANTITIES BEFORE TREATMENT OF OTHER DISPOSAL
A. Waste Quantitites and Volumes for an Average Size Plant Producing
10 Million Ib/yr
Waste Load, 106 Ib/yr
BOD
Urea NDA
Melamine NDA
SS
NDA
NDA
Urea or
Melamine
0.35
0.20
Fo rma Id ehyd e
0.35
0.20
Waste Water Volume,
106 gal/yr*
1.1
0.77
There is no significant variation in unit waste production for
plants of significantly different production outputs. There is no
significant variation in loading by season. Because of the batch
nature of the production, hourly variations can be expected.
B. Total Waste (Quantities and Waste Water Volumes
See II-A, "Typical", "older", and "newer" technologies are similar.
C. Total Waste and Waste Water Quantities/Unit of Physical Product
Waste Load, Ib/lb product
Urea or Waste Water Volume,
BOD SS Melamine Formaldehyde gal/lb
Urea
Melamine
NDA
NDA
NDA
NDA
0.035
0.02
0.035
0.02
0.108*
0.077*
* Process water only.
68
-------
D. Total Waste Quantities and Waste Water Volumes Produced in Base
Year (1963)
Wa st e^ JLjoad, Ib/yr
Urea or Waste Water Volume,
BCD SS Mel ami ne Formaldehyde gal/lb
Urea and g ^
melamine NDA NDA 13.8 x 10 13.8 x 10 47
These figures are based on the combined production of 510 million
Ib of urea and melamine resins.
E. Projected Gross Wastes and Waste Water Volumes
waste Load, 106 Ib/yr
Year
1968
1969
1970
1971
1972
1977
F. Seasonal
Production,
106 Ib/yr
680
720
740
770
800
950
BCD
NDA
NDA
NDA
NDA
NDA
NDA
SS
NDA
NDA
NDA
NDA
NDA
NDA
Urea and
Kelamine
18.3
19.5
20.0
20.8
21.6
25.6
Formaldehyde
18.3
19.5
20.0
20.8
21.6
25.6
Waste Production Patterns
There are no significant seasonal pattern in waste production,
III. WASTE REDUCTION PRACTICES
A. Processing Practices
1. Waste Reduction Efficiency (%) of a Given Subprocess
Relative to Alternate Subprocesses
There are no subprocesses.
2. Sequential Requirements and Interdependencies of Process
Affecting Waste Production
Each time a formulation is significantly changed, the kettle must
be cleaned with caustic. Typically, 350 Ib of 50% sodium hydroxide is
added to a 4000-gal kettle and diluted to 2% with water. On the average,
caustic wash is used after every 10 batches or on a monthly basis.
69
-------
B. Treatment Practices
1.
Normal Removal Efficiency (%) of Waste Treatment Methods in
Treating Waste from a Urea and Melamine Plant of Typical
Technology
Normal Removal Efficiency, %
Removal Method
Lagooning
BCD
SS
Urea and
Melamine
Formaldehyde
Thermal
incineration
Municipal
sewage plant
NDA NDA NDA NDA
Lngoons are constructed so that there is
no overflow of water. Evaporation and
seepage balance inflow. Lagoons can produce
malodors and. -result in air pollution com-
plaints.
100 100 100 100
Thermal incineration can cause air pollution,
depending upon the fuel used and the effi-
ciency of the oxidation process. Theoretically,
the organic matter in the waste water is
converted to carbon dioxide, water, and nitrogen
oxides.
NDA NDA NDA NDA
It is difficult to assign removal efficiency
figures for resin wastes because they are
mixei with many other wastes, including
sanitary sewage.
2. Rate of Adoption of Waste Treatment Practices
Reliable estimated can not be given because of the small sample
size. Most plants, however, either employ lagoons or utilize a municipal
sewer. Thermal incineration is not yet being used on melamine or urea
waste waters.
a. There are no sequential applications of removal techniques
required by technological considerations.
b. Final treatment can be accomplished by lagoons or treat-
ment by a municipal sewage plant or by incineration.
c. There are no interdependencies among the waste removal
techniques that affect costs or relative efficiencies.
3. Combined Wastes
a_. Percentage of_Wa_ste Discharged to Municipal Sewers
The exact figures are unknown but direct discharge to a water course
without treatment or with only quiescent settling was commonplace in the
1950s. Now, many plants discharge their wastes into a municipal sewer.
70
-------
b. Waste Removal Problems Caused by Combining Industrial
with Municipal Wastes
Municipal sewage authorities indicate a high degree of acceptance
for urea and melamine wastes. Difficulties encountered depend on the
type and nature of the treatment. Generally, the difficulties center
around flucuations in pH.. Therefore, combination of urea and melamine
wastes is technically feasible and pretreatment is generally not required.
C. By-product Utilization
There are no by-product uses of wastes nor are new by-products
likely to be developed and marketed in 1968 to 1977.
D. Base Year New Waste Quantities
New Waste Quantities, Ib/yr, reaching
Waste Constituents Watercourses in Base Year 1963*
BOD
SS
Urea and melamine
Formaldehyde
NDA
NDA ,
13.8 x 10
13.8 x 10
Projected Net^ Waste Quantities
Summary of Base Year and
Projected Net Waste Loads
Year Waste
1963 BOD
SS
Resins
Formaldehyde
1968 BOD
SS
Resins
Formald ehyd e
1969 BOD
SS
Resins
Formaldehyde
Gross
Waste
Quantity
Generated,
Ib
NDA
NDA 6
13.8 x 10°
13.8 x 10
NDA
NDA ,
18.3 x 10;
18.3 x 10°
NDA
NDA f.
19.4 x 10°
19.4 x 10°
Percentage of
Waste Reduced
or Removed by
Process Changes,
Waste Treatment,
and By-products
NDA
NDA
-0-
-0-
NDA
NDA
-0-
-0-
NDA
NDA
-0-
-0-
Net Waste
Quantity
Discharged,
Ib
NDA
NDA f-
13.8 X 10°
13.8 x 10
NDA
NDA
18.3 x 10g
18.3 x 10
NDA
NDA fi
19.4 X 10°
19.4 x 10
treatment and without additional treatment such as in a municipal treatment
plant. ?1
281-033 O - 68 - 6
-------
Year
Waste
1970 BCD
SS
Resins
Formaldehyde
1971 BCD
SS
Resins
Fo rma Id ehyd e
1972 BOD
SS
Resins
Formaldehyde
1977 BCD
SS
Resins
Formaldehyde
Gross
Waste
Quantity
Generated,
Ib
NDA
NDA
20.0 x 10
20.0 x 10
NDA
NDA f
20.8 x 10
20.8 x 10
NDA
NDA ,
21.6 x 10
21.6 x 10C
NDA
NDA f
25.6 x 10:
25.6 x 10*
Summary of Base Year and
Prelected Net Waste Loads
Percentage of
Waste Reduced
or Removed by
Process Changes,
Waste Treatment,
and By-products
Net Waste
Quantity
Discharged,
Ib
NDA
NDA
-0-
-0-
NDA
NDA
-0-
-0-
NDA
NDA
-0-
-0-
NDA
NDA
-0-
-0-
NDA
NDA
20.0 x 10:
20.0 x 10
NDA
NDA
20.8 x 10
20.8 x 10
NDA
NDA
21.6 x 10
21.6 x 10*
NDA
NDA
25.6 x 10
25.6 x 10
IV. WASTE REDUCTION AND REMOVAL COST INFORMATION
A.
Replorementjyalue and Annual Operation and Maintenance Expenditures
of Existing Waste Removal Facilities (1966)
Removal Method Replacement Value
Lagooning
Incineration
$25,000/acre
or $800/106 gal*
$150/gal/hr
(typical flows—
100 to 1000 gph)
Municipal sewer Not applicalbe
Annual Operation
and Maintenance Cost
Small
$300/gal/hr
$220 to 850/10° gal**
* Assuming a lagoon depth of 10 ft.
**Sewerage districts use several methods for computing charges. Some
base their charges on hydraulic flow alone; other determine their
charges on the basis of BOD, suspended solids, chlorine demand, and
flow. An example of such a rate schedule is given in Profile Study
SIC-28218 "Phenolic Resins."
72
-------
R. Capital Costs and Economic Life of Processing and Waste Removal
Treatment Equipment
See Section IV-A for capital costs and annual operating and maintenance
expenditures for waste removal treatment equipment. Economic life of
treatment units is 10 to 30 years.
There are no reductions in processing costs due to modified technology
or by-products recovery.
The incremental costs of applying the different techniques to an
existing plant as differentiated from a new plant can be ascertained
from Section IV-A.
73
-------
SECTION 8
SIC 28218 PHENOLIC RESINS
The phenol-derived resins represent the oldest family of resins.
A wide variety of products and uses make up the distribution pattern.
The major uses are for inexpensive casting and plywood bonding. It
is the virtue of cost that causes this product to compete with new more
exotic resins. The process of manufacture has not changed since first
inception and probably will not change. The phenolic products lose
approximately 5% of the very troublesome phenol during synthesis.
The cost removing phenol from process water is very high. The low
rate of growth indicates that the product is in the plateau of its
life cycle and is reflected in the following:
Production,
Year 106 Ib/yr
1962 0.69
1963 0.76
1965 0.90
1967 1.05
1970 1.22
1977 1.50
I. PROCESSES AND WASTES
A. Fundamental Manufacturing Process
The fundamental manufacturing process for phenolic resins is a
batch condensation polymerization of phenolics with formalin (a 40%
solution of formaldehyde in water), the raw materials, phenolics and
formalin, together with catalysts, miscellaneous additives and modifiers
of a proprietary nature. These are charged into a jacketed reaction
kettle and heated to initiate the reaction. Once initiated, the reac-
tion is exothermic; heating is terminated, and cooling water is intro-
duced into the jacket to control the reaction temperature. The mixture
is refluxed until the contents separate into two layers, a heavy viscous
resin layer and an aqueous layer. At this point, vacuum is applied
and the temperature is raised to remove the water. The molten resin is
drained into a pan where it solidifies on cooling.
A flow diagram of the manufacturing process is shown in Figure 15.
B. Significant Water Wastes
The significant water wastes from the production of phenolic
resins are: (1) water introduction with the raw materials, (2) water
formed as a product of the condensation reaction, (3) caustic solutions
74
-------
92 Ib Phenol
73 Ib Formalin
0.3 Ib Catalyst
V
Reactor
i
100 Ib
Phenolic Resin
0)
w
c
-------
used for cleaning the reaction kettles, and (4) blowdown from cooling
towers. The first three waste waters constitute what is normally termed
process water, and the fourth is a portion of the cooling water required
to control the reaction temperature.
From Figure 15 the volumes of the various waste waters can be
estimated. Per 100 Ib of solid resin produced, 5.3 gal of water is
introduced with the reactants and 2.0 gal of water is produced from the
reaction. Caustic cleaning solution is required only when the formula-
tion per kettle is altered significantly. A reasonable estimate of
usage, prorated over a year's production, is 0.01 gal of a 2% sodium
hydroxide solution per 100 Ib of resin. Thus, the process water resulting
from resin production is about 7.3 gal per 100 Ib of resin. About 600
gal of cooling water is required to control the reaction; 42 gal is
discharged to the sewers as cooling tower blowdown, and 558 gal is
r eci r cul at ed.
The waste waters discharged from resin plants have a temperature
of about 85 to 90°F. Thus, thermal pollution is not a problem.
Thermal incineration of the process water can convert a water
pollution problem to an air pollution problem whose magnitude will
depend upon the fuel source, the volume of waste water incinerated,
and the efficiency of the combustion.
C. Reuse of Process^ Water in 1964
Process water was not reused in 1964.
D. Industry Subprocess Mix
Condensation polymerization is the only process by which phenol-
formaldehyde resins are produced. Production technology has shown little
change over the past 20 years, and no new "advanced" technology is fore-
seen. Automated and continuous processing units have been introduced,
but operator-controlled or semiautomated batch production is the most
prevalent. The level of technology has little effect on waste water
volumes or concentrations.
E. Difficult Waste Control Problems of Subprocess
There are no subprocesses.
F. Levels of Technology
Production technology has not changed significantly in the past 20
years, and no new or advanced process technology is foreseen. Thus,
the batch condensation polymerization technology is representative of
"typical," "older," and "newer" subprocesses. No data are available on
the proportion of small, medium and large plants.
76
-------
II. GROSS WASTE QUANTITIES BEFORE TREATMENT OR OTHER DISPOSAL
A. Waste Quantities and Volumes for an Average Size Plant Producing
50 million Ib/yr
Waste Load, 106 Ib/vr Waste Water Volume,*
BCD SS Phenolics Formaldehyde 106 gal/yr
NDA NDA 1.5 0.5 3.6
There is no significant variation in unit waste production for
plants of significantly different production outputs. There is no
significant variation in loading by season. Because of the batch nature
of the production, hourly variations can be expected.
B. Total Waste Quantities and Waste Water Volumes
See Section III-A. Typical, older, and newer technologies are
similar.
C. Total Waste and Waste Water Quantities per Unit of Physical Product
Waste Load, Ib/lb product Waste Water Volume,
BOD SS Phenolics Fo rma Idehyd e gal/lb
NDA NDA 0.03 0.01 0.073*
D. Total Waste Quantities and Waste Water Volumes Produced in Base
Year 1963
Waste Load, 106 Ib/yr Waste Water Volume,
BCD SS Phenolics Formaldehyde 10° qal/yr
NDA NDA 22.8 7.6 55.5
These figures are based on production of 760 million Ib of resin.
E. Projected Gross Wastes and Waste Water Volumes
Production, Waste Load. 106lb/yr
Year
1968
1969
1970
1971
1972
1977
106 Ib/yr
1120
1180
1220
1280
1300
1500
BCD
NDA
NDA
NDA
NDA
NDA
NDA
SS Phenolics Formaldehyde
NDA
NDA
NDA
NDA
NDA
NDA
33.6
35.4 '
36.6
38.4
39.0
45.0
11.2
11.8
12.2
12.8
13.0
15.0
* Process water only
77
-------
F. Seasonal Waste Production Patterns
There are no significant seasonal patterns in waste production.
III. WASTE REDUCTION PRACTICES
A. Processing Practices
1. Waste Reduction Efficiency (%) of a Given Subprocess Relative
to Alternative Subprocesses
Theoretically, the use of solid paraformaldehyde in place of
formalin can reduce the process water volume by 72%. In practice, if
paraformaldehyde is used, some water would have to be added with the
reactants. At present, formalin is almost always used for economic
reasons. The absolute contamination loading, Ib/lb of product, probably
would not be altered by changing to solid paraformaldehyde, however.
2. Sequential Requirements and Interdependences of Process
Affecting Waste Production
Each time a formulation is significantly changed, the kettle must
be cleaned with 2 to 5% caustic. Cleaning may be on a once-a-month
schedule.
B. Treatment Practices
1. Treatment Removal Efficiency (%) of Waste Treatment Methods in
Treating Waste from a Phenolic Resin Plant of Typical Technology
Normal Removal Efficiency, %
Removal Method BCD SS Phenolics Formaldehyde
Lagooning NDA NDA NDA NDA
Lagoons are constructed so that
there is no overflow of water.
Evaporation andseepage balance
inflow. Lagoon can produce
malodors and result in air
pollution complaints.
Extraction of NDA NDA 96 0
phenolics A typical analysis of the waste
water discharged from a phenol
extraction plant is as follows:
78
-------
Removal Method
Normal Removal Efficiency, %
BCD SS Phenolics Formaldehyde
Phenol
BCD
Chlorine demand
Total solids
Volatile solids
Total susp. solids
Volatile susp. solids
PH
1600 ppm*
11500 ppm
68 ppm
500 ppm
250 ppm
40 ppm
20 ppm
6.4
Thermal
incineration
Municipal
sewage
plant
100 100 100 100
Thermal incineration can cause air
pollution, depending upon the fuel
used and the efficiency of the oxi-
dation process. Theoretically, the
organic matter in the waste water is
converted to carbon dioxide and water.
NDA NDA NDA NDA
It is difficult to assign removal
efficiencies for resin wastes be-
cause of admixtures with many other
wastes including sanitary sewage.
2. Rate of Adoption of Waste Treatment Practices
Reliable estimates are unavailable. However, phenol extraction
processes were developed in the 1950s, and the blending of resin
wastes with sanitary sewage and treatment in municipal sewage plants
was accomplished about the same time. Thermal incineration is new but
is being increasingly used, especially as a treatment method in new
plants. Presently, less than 10 plants in the United States thermally
incinerate a portion of their waste waters.
a. Recovery processes such as extraction methods must be employed
before thermal incinferation or blending with other wastes before final
treatment or disposal.
b. Extraction process can be single- or multistage and employ a
variety of solvents. At present, extraction is the only recovery process
used. Final treatment can be either thermal incineration, lagooning, or
blending with sanitary sewage.
c. Extraction processes can be single- or multistage, and a variety
of solvents can be used. . Single-stage plants reduce the phenol content
of the waste water from 5% to a level of 0.1 to 0.2%. Two-stage extrac-
tion reduces the phenol content to 0.01%. Single-stage units cost $70,000,
and two-stage units about $90,000 (1958 dollars). The cost per day per
pound of phenol removal is $12 for a single-stage plant and $88 for the
second stage of a two-stage plant.
79
-------
3. Percentage of Waste Discharged to Municipal Sewers
a. The exact percentage of waste discharged to municipal sewers
is unknown, but in 1950 direct discharge to a watercourse was common
without prior treatment. In 1967 many plants discharge to municipal
sewers even after substantial in-plant treatment.
b. Municipal sewage authorities indicate a high degree of
accommodation for phenolic waste. Studies have shown that both
phenolics and formaldehyde are biodegradable in conventional biological
sewage treatment processes, providing the concentration is maintained
below toxic levels. The difficulties that ao arise are due to fluctua-
tion in pH. Therefore, combination of phenolics and municipal wastes
is technically feasible, and pretreatment is generally not required.
C. By-product Utilization
There are no by-products, nor are new by-products likely to be
developed and marketed in 1968-1977.
D. Base-year Net Waste Quantities
Waste Constituent
BCD
SS
Phenolics
Formaldehyde
Net Waste Quantities Ib/yr Reaching
Watercourses in Base Yearf 1963*
5.3 x 10?
0.02 x lO?
0.91 x 10°
7.6 x 10°
E. Projected Net Waste Quantitites
Year
Waste
Gross Waste
Quantity
Generated,
10b It
Percentage of
Waste Reduced
or Removed by
Process Changes,
Waste Treatment,
and by-products
Net Waste
Quantity
Discharged,
106 lb**
1963
BCD
SS
Phenolics
Formaldehyde
NDA
NDA
22.8
7.6
NDA
NDA
96
0
5.3
0.020
0.91
7.6
out subsequent treatment.
** Figures represent waste discharged from plant using single-stage ex-
traction and do not reflect reductions affected by municipal treatment
plant or any other additional treatment.
80
-------
1969
1970
1971
1972
1977
Waate
BOD
SS
Phenolics
Formaldehyde
BCD
SS
Phenolics
Formaldehyde
BCD
SS
Phenolics
Formaldehyd e
BOO
SS
Phenolics
Formaldehyde
BOD
SS
Phenolics
Formaldehyde
BCD
SS
Phenolics
Formaldehyde
Gross Waste
Quantity
Generated ,
Ib
NBA
NDA
33.6
11.2
NDA
NDA
35.4
11.8
NDA
NDA
36.6
12.2
NDA
NDA
38.4
12.8
NDA
NDA
39.0
13.0
NDA
NDA
45.0
15.0
Percentage of
Waste Reduced
or Removed by
Process Changes,
Waste Treatment,
and by-products
NDA
NDA
96
0
NDA
NDA
96
0
NDA
NDA
96
0
NDA
NDA
96
0
NDA
NDA
96
0
NDA
NDA
96
0
Net Waste
Quantity
Discharged,
1Q6 Ib
7.8
0.029
1.35
11.2
8.3
0.03
1.42
11.8
8.5
0.032
1.47
12.2
9.0
0.034
1.54
12.8
9.1
0.034
1.56
13.0
10.5
0.039
1.8
15.0
IV. WASTE REDUCTION OR REMOVAL COST INFORMATION
A.
Replacement Value and Annual Operating and Maintenance Expenditures
of Existing Waste Removal Facilities (1966)
Removal Method
Lagooning
Annual Operating
Replacement Value and Maintenance Cost
$25,000/acre or
$8000/106/gal*
Small
*• Assuming a lagoon depth of 10 ft.
81
-------
Removal Method Replacement Value
Extraction
first-stage
second-stage
combined
Thermal
incineration
Municipal
sewer
$12/lb phenol
recovered/day
$88/lb phenol
recovered/day
$15/lb phenol
re covered/d ay
$150/gal/hr
(typical flow —
100 to 1000 gph)
Not applicable
Total treatment cost
Capital goods depreciation
Operating and maintenance
Annual Operating
and Maintenance Cost
$6400/10 gal
»
$6400/106 gal
$150/gal/hr
$220 to 850/106 gal*
462 x 10^ $/yr
51 x 10, $/yr
408 x 10 $/hr
B. Capital Cost and Economic Life of Processing and Water Removal
Treatment Equipment
Total capital cost: $1,344 x 10
See Section IV-A for capital costs and annual operating and main-
tenance expenditures for waste removal treatment equipment. The
economic life of extraction units if 10 to 30 years.
Schedule of Rates for Waste Treatment
by a Regional Sewerage Authority
1. Flow
Million Gallons
per Quarter
First 5
Next 5
Next 30
Next 60
Next 100
Next 200
Next 400
at
at
at
at
at
at
at
Charge per
Million Gallons
$413.86
$272.23
$200.29
$ 95.72
$ 50.02
$ 41.39
$ 36.52
* Sewerage districts use several methods for computing charges. Some
base their charges on hydraulic flow alone; others determine their
charges on the basis of BOD, suspended solids, chlorine demand, and
flow. An example of such a rate schedule is attached.
82
-------
2. Biochemical Oxygen Demand
Tons per Quarter Charge per Ton
First 30 at $ 21.07
Next 70 at $ 19.75
Next 100 at $ 17.80
Next 200 at $ 15.72
Next 400 at $ 12.61
Over 800 at $ 10.48
3. Suspended Solids
Tons per Quarter Charge per Ton
First 10 at $ 29.22
Next 70 at $ 28.24
Next 170 at $ 23.86
Next 450 at $ 13.51
Over 700 at $ 12.84
4. Chlorine Demand*
Short Hundredweights Charge per Short
per Quarter Hundredweights
First 30 at $ 12.59
Next 60 at $ 11.50
Next 180 at $ 11.07
Next 540 at $ 10.51
Over 810 at $ 9.86
The economic life of other methods is not known.
There are no reductions in processing costs due to modified tech-
nology or by-product recovery.
The incremental costs of applying the different techniques to an
existing plant as differentiated from a new plant can be ascertained
from Section IV-A.
83
-------
SECTION 9
SIC 28219 MISCELLANEOUS RESINS
Miscellaneous resins are a chemically unrelated resins that have
one common dimension, low-volume production. Several of the resins, as
indicated, generate no water wastes. Some of the specialty resins are
manufactured by just a few companies. Accurate treatment practices and
costs were not available.
The accumulative production and projected growth rate for miscella-
neous resins is, as indicated below, excellent
Production,
10* Ib/yr
0.65
0.76
1.03
1.25
1.65
2.00
I. POLYURETHaNE
The principal use of polyurethane is in the production of plastic
foams. Thermoplastic foams can be produced from styrene, vinyls,
polyethylene, and cellulose acetate. Thermosetting foams can be pro-
duced from urethane, epoxy, phenolic, urea-formaldehyde, and silicones.
In the case of urethane, either a chemically released gas (carbon dioxide)
or a low-boiling solvent (fluorcarbon, F-ll) is used for blowing. The
densities range from 1.5 to 4 Ib/cubic foot. The final product is
poured and molded, poured-in-place, or sprayed-in-place.
Urethane foams have dominated the furniture applications for foamed
plastics. Because of the ease of in-place application and high insulat-
ing value per unit volume (excellent K values), the potential growth
for insulation is very good. For versatility, the urethanes can be
mixed with vinyl, pblyolefin, and styrene foams.
Urethanes are used mainly for foams (70% in 1962, est. 40% in 1970).
Other uses are in elastomers, adhesives, fibers, paints, and coatings.
The urethane plastic is synthesized in all cases by the reaction of a
polyisocyanate (such as toluene diisocyanate) and a polyhydroxy compound
(such as polyols, glycols, polyesters, and polyethers). The reaction
mixture, including 0.1 to 0.5% catalyst (i.e., amines, metal soaps, etc.)
generates a gas that forms bubbles of controlled size and volume. The
gas released is generally carbon dioxide. The manufacturing procedure
provides for protection against contamination by water, which would
change the rate and nature of the foaming reaction.
84
-------
The production of polyurethanes creates no known water wastes.
There is no known new technology in sight that would produce water
Bastes. It is expected that water wastes will not be significant
through 1977.
The above-described excellent characteristics cause this product
to have a high growth rate.
Production
109 Ib/yr
0.200
0.250
0.380
0.500
0.985
1.000
II. EPOXY
The earliest commercial epoxy resin and the one that still accounts
for 80 to 90% of the epoxy resin epichlorohydrin. The term resin is
somewhat of a misnomer when applied to the epoxies since these products
are, for the most part, resin intermediates or prepolymers. They are
initially thermoplastic materials that are converted in their final
application into hard, tough, infusible thermosetting polymers by
reaction with suitable hardeners (at least 100 different chemical are
used to cross-link or harden this prepolymer.) No water wastes are
created in the cross-linking, or hardening, step.
One important advantage of epoxies is that they can be formulated
so that upon curing there is very little change in volume. This is
of great advantage in tool and die work where the great toughness of
epoxy resin can be used to replace expensive metal dies.
A very small number of manufacturers produce the linear prepolymer.
This prepolymer is sold to approximately 100 formulators that supply
specialty products to numerous small accounts in this business. There
are hundreds of specialty applications for epoxies.
In a typical synthesis of the prepolymer, 2.5 gal of waste water
is generated for each pound of epoxy resin produced. This would
generate 425x10 gai of waste water per year. The nature and con-
centration of wastes were not available. The largest producer (50% of
total production) stated that they have developed a process for
synthesizing epoxy resins where no waste water is generated. Information
obtained indicated that waste loads are "relatively small" and little
waste treatment is required.
The following indicates that a moderate to good growth is expected
for epoxy resins.
85
-------
Production,
1(T Ib/yr
0.060
0.090
0.118
0.150
0.225
0.260
III. ACETAL
The first commercial product was introduced in 1959. Since that
time four other companies have brought out competing products. The
product is relatively expensive; it competes mainly with metals.
The acetal resin, polyoxymethylene, is a highly crystalline
polymer composed of repeating CH-O groups. The process of manufacture
remains undisclosed. The identification and quantification of water-
borne wastes remain undisclosed. It is surmised that the product is
formed by polymerization of formaldehyde follwed by a unique method
of thermal stabilization. It is further surmised that since the final
product is comprised of, at least 75% unbranched polyoxymethylene
chains (-OCHjOCH--) that production has proceeded with no release of
either water units or other chemical fragments. On this basis, it is
assumed that no significant water wastes are generated.
The following indicates relatively low production with a minimal
growth pattern.
Production,
10 Ib/vr
0.01S
0.030
0.047
0.050
0.060
0.070
IV. POLYCARBONATES
Polycarbonate resins are a new class of resins introduced
commercially since I960.. There are now three suppliers. It is
specialty product with the following current usage:
86
-------
%
Appliance, lighting 34
Electrical, electronic 29
Safety, food, medical 13
Film and sheet 08
Plumbing 08
Miscellaneous 08
The general method of synthesis provides for preparation of a
molding resin by reacting bisphenol A with carbonyl chloride. Hydro-
chloric acid is given off and must be neutralized. The resulting
product is a thermoplastic resin consisting of bisphenol groups joined
together by carbonate linkages. For modification various phenols and
bridge molecules can be included in the structure of the product.
The water waste load is estimated at 1 gal/lb of product, and the
quantity of the water per unit of production is not available.
The growth rate to a modest volume is reflected below.
Production,
Year 10s Ib/vr
1962 0.005
1963 0.008
1965 0.030
1967 0.040
1970 0.090
1977 0.100
V. SILICONES
The first commercial production of silicones occurred in 1943.
There are now four major producers of silicones. The resins are
primarily used in electrical equipment because of their excellent
dielectric properties and heat stability. Silicone elastomers are
used for wire and cable insulation. The second largest consumer is
industrial paints.
The manufacture of silicone fluids, silicone resins, and related
products is quite simple in outline. After the production of suitable
chlorosilane compounds, the desired product is produced by hydrolysis
to form the polymer. For larger-scale production of silicone fluids,
continuous processing is applied. For production of resins, batch
processing is employed. An extreme range of products exhibiting a
broad panorama of physical properties can be produced by starting with
various chlorosilanes and varying the production procedure.
For each unit of silicone in the product, two moles of hydrogen
chloride are produced. This generated hydrochloric acid is etiher
neutralized or diluted before release to a stream. The final product
must be carefully washed, which creates a certain organic waste load.
The identification and quantification of this organic waste load was
87
-------
not available for this study.5 The waste water load is estimated at
4 gal/lb of product, or 60 10 gal/yr. One major supplier stated that
they had a process in the pilot-plant stage that produced no waste.
The price of the silicones are relatively high. This product
appears to have reached the plateau in its life cycle, as indicated
below.
Production,
Year 109 Ib/yr
1962 0.0085
1S63 0.011
1965 0.012
1967 0.015
1S70 0.015
1977 0.020
VT. NYLON 6
Nylon 6 is a linear polyamide with an average molecular weight of
19,000. The suffix 6 designates the oionomeric starting material, which
in this case is caprolactam. Nylon 6 accounts for about 25% of the
total U.S. nylon production. The bulk of Nylon 6 production is used
for carpeting, tire cord, and textiles. The remaining fiber production
finds industrial usage in items such as seat belts, parachutes, rope,
etc. Nylon 6 is also produced as extruded fiber and certain molded
products.
The polymerization process for Nylon 6 is basically the same for
all producers. Caprolactam is melted at 70 to 85°C under nitrogen in
a large blending tank. Several additives are blended at this stage,
including a molecular-weight regulator (0.05 to 0.15% acetic acid), a
delustering agent (0.3 to 1.0% titanium dioxide), a catalyst (usually
2 to 5% water), and stabilizers for light and/or heat.
The charge is fed to a polymerication reactor and held for 20 hr
at 250 to 270°C at 1 atm of pressure. The molten polymer is then
extruded through a 1/8-in orifice into a water chill bath where it
solidifies. The product is then chopped into short segments or chips.
These chips contain about 9 to 11% water extractables. The water
extractables contain 70% unreacted monomer, 10% higher lactam and 20%
low-molecular-weight amino acids. The water solubles are not usually
removed by the producer but are left in the pellets. The processers in
turn, in many cases, do n.ot remove the water solubles. What percent
of the water solubles is removed from rhe total production and what
percent of this is treated was not available for this study. One
manufacturer has installed facilities to recover the unreacted monomer
for reuse. What becomes of the low-molecular-weight amino acids in
this process is unknown.
88
-------
On the basis that most manufacturers leave the water solubles in
the final product or recovers the valuable monomers, it is assumed that
water wastes are minimal. The literature has several references to
various methods of vacuum stripping for removing monomeric components.
Considerable variance exists between sources on production figures and
future volume projections. All agree that the growth rate is healthy,
as reflected in the following.
Production,
Year 10s Ib/yr
1962 0.033
1963 0.038
1965 0.050
1967 0.100
1970 0.150
1977 0.200
VII. COUMARONE-INDENE
Under the general classification of coumarone-indene resins are
included both resins produced from coal tar by-products and those
produced from petroleu.ii refinery products (hydrocarbon resins) . The
major uses are for floor tile (25%) and rubber compounding (25%). The
remaining 50% is used as an inexpensive extender for plastics and other
miscellaneous uses.
The general manufacturing process for both raw material sources is
very similar. The highly cracked hydrocarbon fractions from either
coal-tar oils or from petroleum are processed. In the case of coal-tar
oils, both coumarone and indene are present, leading to the generic
name applied to the class. The recovery and use of a similar fraction,
which is mainly highly unsaturated hydrocarbons, from petroleum is
proportinately increasing. The production is currently 50/50 from
each source. The general procedure for synthesizing the resin from
cracked hydrocarbon fraction is to batch mix the hydrocarbon -with a
low-cost acid, i.e., 2 to 3% sulfuric acid. The oil-acid mixture is
heated to effect polymerization. A neutralizing material is then added.
The resultant product is either heated to drive off excess water and
the residues are left in the product, or water washing may be applied.
Accurate data relative to proportions of product production treated in
each manner are not known. A typical figure of waste generation is
0.25 gal of waste water per pound of production. The biodegradsable
waste generated is 0.001 Ib BOD per Ib of product.
Production,
109 Ib/yr
0.290
0.325
Q.325
0.310
0.300
0.300
89
-------
VIII.MISCELLANEOUS RESINS
The annual operating and maintenance expenditure^ of existing
waste removal faculities for the miscellaneous resins are:
Treatment cost 34 x 10^ $/yr*
Capital good depreciation 13 x 103 $/yr
Operating and maintenance 21 x 10 $/yr
The capital cost and economic life of waste removal equipment for
miscellaneous resins are:
Capital cost 0.382 106 $/yr
Economic life 30 yr
*Of those resins generating waste, only data on coumarone-
indene resins were available.
90
V. S. GOVERNMENT PRINTING OFFICE : 1968 O - 287-033
------- |