FEDERAL WATER POLLUTION CONTROL ADMINISTRATION
NORTHWEST REGION, PACIFIC NORTHWEST WATER LABORATORY
plywood plant glue wastes disposal
march • 1969
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FEDERAL WATER POLLUTION CONTROL ADMINISTRATION
NORTHWEST REGION, PORTLAND, OREGON
James L. Agee, Regional Director
PACIFIC NORTHWEST WATER LABORATORY
Corvallis, Oregon
A. F. Bartsch, Director
_____ iii :
NATIONAL THERMAL NATIONAL EUTROPHICATION
POLLUTION RESEARCH RESEARCH
Frank H. Rainwater A. F. Bartsch
NATIONAL COASTAL WASTE TREATMENT RESEARCH
POLLUTION RESEARCH AND TECHNOLOGY: Pulp &
D. J. Baumgartner Paper; Food Processing;
Wood Products & Logging;
BIOLOGICAL EFFECTS Special Studies
Gerald R. Bouck James R. Boydston
TRAINING CONSOLIDATED LABORATORY
Lyman J. Nielson SERVICES
Daniel F. Krawczyk
TECHNICAL ASSI STANCE
AND INVESTIGATIONS POLLUTION SURVEILLANCE
Danforth G. Bodien Barry I-I. Reid
WASTE TREATMENT RESEARCH
AND TECHNOLOGY
SPECIAL STUDIES BRANCH
Donald J. Hernandez, Chief
Danforth G. Bodien*
B. David Clark
Robert D. Shankland
R. Stewart Avery**
Cecil A. Drotts
Judy K. Burton
* Now assigned to Technical Assistance and Investigations
Now assigned to Food Wastes Research Branch
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PLYWOOD PLANT GLUE WASTES DISPOSAL
Final Report
A Technical Projects Report
No. FR-5
by
Danforth G. Bodien
United States Department of the Interior
Federal Water Pollution Control Administration, Northwest Region
Pacific Northwest Water Laboratory
200 South 35th Street
Corvallis, Oregon 97330
January 1969
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ABSTRACT
In the States of Oregon, Washington, Idaho, Montana, and
California, 158 plywood plants generate an estimated 6.2 million
gallons of wastewater per day from the cleanup of glue mixing
equipment and glue spreaders. Some of the wastes are toxic to
fish and all are high in pollutional strength. Treatment of these
glue wastes varies from plant to plant, but generally consists
only of solids separation or the removal of suspended matter.
Biological treatment investigations showed that BOD removals
of 90+ percent can be attained where protein and urea glues are
involved; however, this process proved unworkable for the phenolic
glues and the process of incineration was shown to have good
potential. Wastewater reuse offers the best waste disposal
answer for the phenolic glues and possibly also for the protein and
urea glues.
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CONTENTS
Page
INTRODUCTION
Problem i
Authority . . 2
Objectives and Scope 2
Acknowledgments 2
SUMMARY
Findings 5
Conclusions 7
Recoimiendations 7
PLYWOOD PLANT SURVEY 9
PLYWOOD PLANT CHARACTERISTICS
Location and Number 11
Production 11
Operations 15
Green End 15
Layup 15
Trends 21
WASTE CHARACTERISTICS
Waste Quantity. 25
Measured Waste Discharges. . 25
Calculated Waste Discharges. 33
Waste Quality 35
Chemical Investigations. . . . . . 35
Pollutional Effects . . . 38
Stream Survey 38
Toxicity Studies. . . . 38
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CONTENTS (Continued)
TREATMENT AND CONTROL
Methods in Use
Biological Treatment Studies
Protein Glue Studies. .
Phenolic Glue Studies .
Urea Glue Studies
Physical-Chemical Treatment Studies.
Neutralization
Incineration
Wastewater Reuse
BIBLIOGRAPHY
DEFINITION OF TERMS
Page
47
51
51
59
61
63
63
72
74
79
81
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LIST OF TABLES
No. Page
1 Number and Percentage of Plants Surveyed 9
2 1966 Plant Production - By Type and Grade - of
Plants Surveyed 10
3 Number of Plants by Types of Plywood 11
4 1966 Plant Production by Types of Plywood . . . • 13
5 Green Ends, Cold Decks, and Log Ponds • 17
6 Number and Size of Log Ponds at Plants Surveyed . • • 18
7 Number of Glue Spreaders for Plants Surveyed. . 20
8 Number of Spreader Shifts for Plants Surveyed . . 21
9 Current and Projected Adhesive Consumption in
the Plywood Industry • . 22
10 Characteristics of Plants Used in Discharge Study 25
11 Glue Waste Discharge Measurements 32
12 Ingredients of Typical Protein, Phenolic and
Urea Glue Mixes 36
13 Average Chemical Analysis of Plywood Glue . . . . . . 37
14 Anderson Creek - Physical Observations 42
15 Acute Toxicity Characteristics of Various Plywood
Glues 44
16 Disposal Method of Plants in Survey 48
17 Chemical Analysis of Settled Effluent 49
18 Biological Treatment of Protein Glue 55
19 Biological Treatment of Urea Glue 62
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LIST OF TABLES (Continued)
Page
No.
20 Neutralization of Protein Glue Waste 70
21 Alum vs H 2 S0 4 For Neutralization of Phenolic Glue
Waste 71
22 Incineration Test for Phenolic, Protein and Urea
Glue 73
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LIST OF FIGURES
No. Page
1 Plywood Plant Locations . . . . • • 12
2 Projected Growth in Demand for Plywood, 1950—2000
3 Plywood Plant Flow Diagram.
Glue Mixing Area
Glue Spreader
Average Glue Waste Flows (Plant 1).
Daily Average Glue Waste Flows (Plant 2).
Daily Average Glue Waste Flows (Plant 3).
Daily Average Glue Waste Flows (Plant 4).
Anderson Creek Sampling Sites
Activated Sludge Pilot Plant Flow Diagram
Activated Sludge Pilot Plants
BOO vs COD for Borden’s Casco S-230
13 BOD vs COD for Borden’s Casco S-230 Protein Glue.
14 Influence of Loading on BOD Removal for Borden’s
Casco S-230 Protein Glue
15 Titration Curves for Phenolic and Protein Glue.
16 Titration Curve for Hardwood Glue
17 COD and TOG of Supernatent vs pH for Protein Glue
18 COD of Supernatent vs pH for Phenolic Glue. .
19 Reuse System Flow Diagram
20 Reuse System Showing Settling Tank, Pump and Roof
Storage Tank.
4A
4B
5
6
7
8
9
10
11
12
14
16
19
19
26
28
29
30
40
52
53
56
57
58
65
• • . 66
67
68
76
77
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PLYWOOD PLANT GLUE WASTES DISPOSAL
INTRODUCTION
Probl em
The cleanup of glue spreaders at plywood mills produces a
waste that is high in pollutional strength, though quite low in
volume. At the present time, the State of Oregon rates this
waste as its primary water pollution problem, based on the number
of complaints received.
The plywood industry uses three basic types of glue: the
blood-soya, or protein variety, for interior grade plywood; the
phenolic formaldehyde variety used primarily for exterior grade
plywood; and a urea formaldehyde glue used for hardwood paneling.
Each presents its own waste disposal problem and any combination
of these may compound the problems.
The blood-soya glues produce an alkaline waste with a high
oxygen demand. Coagulation of the glue soltds may cause large
masses of solids resulting in sewer stoppage. The waste also
supports the growth of Sphaerotilus sp.
Phenolic formaldehyde glues produce a toxic, alkaline waste
which creates color, taste, and odor problems in a receiving water.
The urea formaldehyde glue wastes differ from the others,
being acidic in nature. These glues are used for less than
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2
8 percent of the plywood production in the study area. For this
reason, most of the work here reported had to do with the blood-
soya and phenolic glues.
Authority
The Pacific Northwest Water Laboratory of the Federal Water
Pollution Control Administration, Northwest Region, was requested
by the Oregon State Sanitary Authority, letter dated January 19,
1966, to study methods for disposing of glue wastes from plywood
plants. Authorization for this study was from the Federal Water
Pollution ContrQl Act, as amended.
Objectives and Scope
This study was carried out to determine the magnitude and
extent of the problem created by the disposal of glue wastes,
review the characteristics of plywood glue wastes, and recommend
methods of treatment for these wastes.
The study area includes the States of Oregon, Washington,
Montana, Idaho, and California. Basic information on plywood
plants was collected from plants in all five states, while field
work was confined to plants in Oregon that are representative of
the industry.
Ackriowl edgments
Acknowledgment is made of the American Plywood Association’s
valuable assistance in conducting a survey of waste generation
and disposal practices at its member plants.
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3
Special thanks are tendered to the Borden Chemical Company
at Springfield, Oregon, for its donation of glue ingredients and
assistance in explaining and defining techniques involved in
preparing the glue mixes.
Thanks are expressed also to the personnel of the many plants
visited for their great interest and cooperation.
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SUMMARY
Findings
1. Approximately 158 plywood plants in the study area
generate an estimated 6.2 million gallons of waste per day from
the cleanup of glue spreaders and glue mixing equipment.
2. Average water usage at four plants surveyed ranged from
18,800 to 76,500 gallons per day. This variation has no apparent
relationship to type of glue used or amount of plywood produced.
3. Less than 250 gallons of water are needed to wash down
a glue spreader.
4. Based upon the production of surveyed plants, phenolic
and protein glues each contribute approximately 48 percent of the
total waste with urea glue contributing the remaining 4 percent.
5. All three types of glue studied exhibit high pollutional
strength. Chemical oxidation demands (COD) measured were
177,000 mg/kg protein glue, 653,000 mg/kg phenolic glue and
195,000 mg/kg urea glue. The protein and phenolic glues are
alkaline in nature while the urea glue is slightly acidic. The
protein and urea glues possess adequate nutrients for biological
treatment while the phenolic glue requires supplemental additions
of nitrogen and phosphorus.
6. The discharge of untreated glue waste has a damaging
effect upon the biota of receiving waters.
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6
7. The protein glue wastewaters exhibited an average 96-
hour median tolerance limit (TLm) of 4,500 mg/l on guppies while
the phenolic glue wastewaters proved more toxic with an average
96-hour TLm of 1,140 mg/i.
8. Seventy-three percent of the plants surveyed provide
settling devices of various types which remove the wood chips
and a portion of the glue solids; seventeen percent of the plants
surveyed dump raw wastes into city sewers, rivers, the ocean, and
other receiving waters.
9. Most settling tanks and basins in use at plants are
inadequately maintained, leading to very low removal efficiencies.
10. Biological treatment employing detention times of 8,
12, and 16 hours were used for the protein glue while 16 hours
and 5 days were used for the urea glue. At all these detention
times, Biochemical Oxygen Demand (BOD) removals of 90+ percent
were achieved at loadings as high as 50 lbs BOD/100 lbs Mixed
Liquor Suspended Solids (MLSS).
11. Attempts to acclimate a biological system to handle
phenolic glue waste were not successful.
12. Neutralization and settling of protein or phenolic glue
wastewater using either alum, sulfuric acid, or hydrochloric acid
removed 99+ percent of the COD and TOC. These good removals were
accompanied by the production of large amounts of sludge ranging
from 065 ft. 3 /lb phenolic glue for acid neutralization to 0.98
ft. 3 /lb phenolic glue for alum neutralization.
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7
13. Glue solids can be burned at high temperatures producing
only small percentages of ash. Based upon the wet weight of the
glue ash, productions of ash ran 4.12 percent, 6.12 percent, and
nil for phenolic, protein, and urea glue, respectively.
Conclusions
1. Far more water is used at most plants than is required
to wash down the spreaders and glue mixing equipment.
2. Biological treatment is an effective method for treating
protein or urea glue wastes. Nutrient addition and acclimation
are not needed.
3. Biological treatment was not found to be feasible for
wastes containing pheriolic glues.
4. Neutralization was found to be a feasible treatment
process. However, provision must be made for handling the large
amounts of sludge produced.
5. Wastewater reuse is by far the most feasible treatment
system for phenolic glue waste.
6. If a wastewater reuse system proves workable for protein
and urea glues, the problem of glue waste can be eliminated.
Recommendations
It is recommended that:
1. The practice of discharging untreated glue wastes to
municipal sewer systems or receiving waters be discontinued.
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8
2. All plants take the necessary steps to reduce their
waste volumes. This reduction is a necessity if a system of
wastewater reuse or incineration is to be employed.
3. All plants install and properly maintain adequate
size settling tanks or basins for the removal of suspended
matter. Screening of the waste prior to settling would
improve the operation of the settling device by removing large
glue solids and wood fragments. Screenings and sludge from
these settling tanks and basins should be disposed of by in-
cineration, landfill, or another acceptable method.
4. Plants using phenolic glues develop and utilize a
wastewater reuse system, thus eliminating the need for waste
discharge. If a reuse system cannot be used, incineration
should be investigated before considering neutralization.
5. Plants using protein or urea glues investigate the
possibilities of wastewater reuse. If this process proves
infeasible, incineration or biological treatment could be used.
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PLANT SURVEY
Plywood plants vary in many respects such as size, type of
waste generated, and waste disposal methods. To gain an under-
standing of the plywood industry, this study employed two methods:
the first involved visits to 52 plants, all in the State of Oregon;
the second obtained from the American Plywood Association (APA)
information which the Association itself collected in a survey
of its member plants concerning production, operations, waste
generation, and disposal practices.
To obtain a good response, the APA supervisors filled out
questionnaires on their routine visits to the plants in their
respective districts. This gave a 100 percent return for the
APA plants. From Tables 1 and 2 it can be seen that the APA
survey represented about 67 percent of all plants, and 70 percent
of the plywood production in the study area, a representative
sample of the industry.
TABLE 1
NUMBER AND PERCENTAGE OF PLANTS SURVEYED -”
Number of Number of Plants % of Plants
State Plants Surveyed Surveyed
California 22 11 50
Idaho 4 2 50
Montana 6 4 67
Oregon 92 59 64
Washington 34 30 88
TOTALS 158 106 67
a!
APA Survey, 1967
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TABLE 2
1966 PLANT PRODUCTION - BY TYPE AND GRADE - OF PLANTS SURVEYED
a/
Softwood
Production
(Sq. Ft.
State Interior Grade
3/8” Basis)
Exterior Grade
Hardwood
(Sq. Ft.
Production
3/8” Basis)
Total
(Sq. Ft.
Production
3/8” Basis)
California
Idaho
Montana
Oregon
Washi ngton
TOTALS
PERCENT OF
TOTAL
345,480 ,000
112,200,000
274,764,000
2,760,048,000
889,272,000
4,381 ,764,000
230,820,000
27,000,000
118,836,000
2,874,252,000
1,165,800,000
2,416,708,000
11,460,000
310,128,000
321 ,588,000
576,300,000
139,200,000
393,600,000
5,645,760,000
2,365,200,000
9,120,060,000
APA Survey, 1967
48.0 48.4 3.6
100.0
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PLYWOOD PLANT CHARACTERISTICS
Location and Number
The locations of the 158 plywood plants in the five—state
study area are shown on Figure 1. The plants are concentrated
in the Willamette and Rogue River Valleys in Oregon and the Puget
Sound area in Washington. Table 1 shows the distribution of the
158 plants by state. As can be seen, Oregon has 92 plants or
approximately 58 percent of the total. Table 3 breaks down the
plants surveyed by type of plywood produced. Comparison of the
tables shows that a good cross-section was obtained by the survey.
TABLE 3
NUMBER OF PLANTS BY TYPES OF PLYWOOD -”
State
Softwood
Plants
Hardwood
Plants
Mixed
Plants
Total
Plants
California
17
4
1
22
Idaho
4
0
0
4
Montana
6
0
0
6
Oregon
84
2
6
92
Washington
22
2
10
34
TOTALS
133
8
17
158
Producti on
Despite a slump in new housing starts, plywood demands have
continued to grow. This growth is expected to continue, increasing
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FIGURE 1
PLYWOOD PLANT LOCATIONS
..
.
S
1
S
.
I
S
S
S
OREGON
S
.
S
IDAHO
S
CALIFORNIA
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13
an estimated eightfold by the year 2OOO -”. This expected
growth rate is shown in Figure 2.
Plywood production for 1966, a normal year, is given in
Table 4. These data give the hardwood and softwood production by
states and show that, in the study area, the softwood makes up
92.1 percent of the total . The State of Oregon in 1966 produced
64 percent of the total plywood for the five states in the study
area.
TABLE 4
1966 PLANT PRODUCTION BY TYPES OF PLYWOOD—
Softwood Production Hardwood Production Total Production
State (Sg.Ft. 3/8” Basis) (Sg.Ft. 3/8” Basis) (Sg.Ft. 3/8” Basis )
California 1,277,000,000 115,500,000 1,392,500,000
Idaho 293,100,000 -—- 293,100,000
Montana 456,000,000 --- 456,000,000
Oregon 7,948,350,000 499,450,000 8,447,800,000
Washington 2,150,600,000 427,500,000 2,578,100,000
TOTALS 12,125,050,000 1,042,450,000 13,167,500,000
92.1 7.9
Table 2 gives the 1966 production for the plants surveyed.
In this table, the softwood production is further divided into
interior and exterior grades. The survey shows that the production
totals for interior and exterior grades are very similar, being
48.0 and 48.4 percent, respectively. Hardwood plywood production
accounts for the remaining 3.6 percent.
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/
/
I
HARDWOOD PLYWOOD
(SURFACE SQ. FT.) 1
1960 1970
1980 990
2000
DEMAND
1950 - 2000
hO
$05
95
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
/
00
90
85
80
75
70
65
60
55
50
45
40
35
30
25
20
15
10
SOFTWOOD
I
I
I
I
I
I
I—
LU
LU
LL
LU
U)
z
0
-J
-J
PLYWOOD (3/ØM BASIS)
/
I
I
I
/
I
I
F
/
/
/
/
/
/
/
/
/
/
/
/
/
I
/
I
,
5
0
l9
FIGURE 2.
YEAR
P ROJ ECTE D GF DWTH IN
FOR PLYWOOD 1
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15
Operations
To help understand the plywood operations, a flow chart of
a complete plant is shown in Figure 3. This flow chart also
indicates sources of solid and liquid wastes.
Green End
The green end of a plant involves the storage and
handling of logs through the process of turning them into veneer.
Storage of logs may be in a log pond, a cold deck, or a combina-
tion of both. Log ponds at plywood plants usually serve further
as a disposal site for the glue wastes. This rids the plant of
the glue waste but usually complicates pollution problems caused
by the log storage. Cold decking also causes some pollution
problems; water sprayed over the logs to keep them from checking
usually finds its way into the log pond or to another receiving
water body. Table 5 presents data on green ends, log ponds, and
cold decks. Of the plants surveyed, 82.1 percent have green ends.
Of those having green ends, 63.2 percent have log ponds, and 59.4
percent have cold decks. Table 6 presents more detailed informa-
tion on the log ponds. The average size log pond for the plants
surveyed was 17 acres, with a range from 0.5 to 100 acres.
Lay
The first potential source of glue waste is the washdown
of kettles and equipment used for mixing and storing the glue. A
typical plant, producing 100 million square feet (3/8 inch basis)
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FIGURE
3.
PLYWOOD
PLANT
FLOW
DIAGRAM
GREEN END
— , SOLID WASTE
LIQUID WASTE
WASTE
THIS WASTE IS BURNED
OR CHIPPED FOR REUSE
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17
of plywood per year, approximately 50 percent exterior and 50 per-
cent interior grades, makes up about 11 batches per day of protein
glue and 9 batches per day of phenolic glue. This amounts to
approximately 400,000 pounds of phenolic and 350,000 pounds of
protein glue per month. The mixing equipment may not always be
washed between batches or in some cases, may not be washed at all,
but if it is washed, only a small amount of water should be used.
Thus, any waste generated by this phase of the operation is a
small but highly concentrated part of the total. A glue-mixing
area from a typical plant is shown in Figure 4-A.
GREEN ENDS, COLD
TABLE 5
DECKS’, AND LOG PONDS!!
State
California
Idaho
Montana
Oregon
Was hi ngton
Plants Surveyed
with
Green Ends (% )
90.9
100.0
100.0
83.1
73.3
Plants Surveyed
with
Cold Decks (% )
72.7
100.0
100.0
57.6
50.0
Plants Surveyed
with
Log Ponds (%)
27.3
0.0
16.7
72.9
56.7
WAPA Survey, 1967
The second source of glue waste is the spreaders.
glue spreader from a typical plant can be seen in Figure 4-B.
A
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TABLE 6
NUMBER AND SIZE OF LOG PONDS AT PLANTS SURVEYED
Number
of
Total Size
Avg.
Size
Max.
Size
Mm.
Size
Plants
of Ponds
of
Ponds
of
Ponds
of
Ponds
State With Ponds
(Acres)
(Acres)
(Acres)
(Acres)
—
California 6 88.5 14.8 30.0 2.5
Idaho 0 0.0 0.0 0.0 0.0
Montana 1 7.5 7.5 7.5 7.5
Oregon 43 865.5 20.1 100.0 1.5
Washington 17 169.5 10.0 75.0 .5
TOTAL 67 1,131.0
AVERAGE
FOR 5 STATES 16.9
MAXIMUM SIZE FOR 5 STATES 100.0
MINIMUM SIZE FOR 5 STATES .5
APA Survey, 1967
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FIGURE 4
A. GLUE MIXING EQUIPMENT
B. GLUE SPREADER
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20
Table 7 gives data on the number of spreaders in the plants
surveyed. As can be seen, the plants have from one to nine
spreaders each, with a plant average of three. Of more interest
is the number of spreader shifts per day as these, along with
type of glue used, determine the number of washdowns. Table 8
contains data on spreader shifts for the surveyed plants. The
plantssurveyed average slightly over six spreader shifts per day
with a range of from one to twenty. The spreaders are usually
washed down once per shift when protein glue is used and at
least once per day for phenolic glue. The difference is due
to the fact that the protein glues have a pot life of six to
eight hours, whereas the phenolic glue lasts almost indefinitely.
Whereas spreaders using phenolic glue need be washed down only
once per day, the accumulation of wood chips in the pans usually
necessitates a rinsing at the end of each 8—hour shift.
TABLE 7
NUMBER OF GLUE SPREADERS FOR PLANTS SURVEYED -”
Average! Max.! Mm .!
State Number Plant Plant Plant
California 24 2.2 4 1
Idaho 3 1.5 2 1
Montana 10 2.5 4 2
Oregon 179 3.0 9 1
Washington 94 3.1 6 1
TOTAL 310
Average 2.9
Maximum 9
Mininium 1
‘APA Survey, 1967
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21
TABLE 8
NUMBER OF SPREADER SHIFTS FOR PLANTS
a!
SURVEYED
State
Total
Number
Average
Plant
Max.!
Plant
Mm.!
Plant
California
42
3.8
7
1
Idaho
8
2.0
5
3
Montana
25
6.3
11
4
Oregon
406
6.9
20
2
Washington
185
6.2
16
1
TOTAL
666
AVERAGE
6.3
MAXIMUM
20
MINIMUM
1
a!
APA Survey,
1967
Trends
Three trends of the plywood industry are of interest froa
a water pollution standpoint. These trends involve production,
adhesive consumption, and glue application.
As was pointed out earlier, plywood production is expanding
at a fairly rapid rate. The year 2000 will see an estimated
2/
eightfold increase over present prodution . This means that waste
treatment efficiencies will have to improve as more waste is generated.
For example, if 90 percent treatment is required in 1967, 98.75 percent
treatment will be necessary in 2000 to maintain the sai e pollutional
load on receiving waters.
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22
The second trend concerns the adhesives used by the industry.
Table 9 shows current and projected adhesive consumption for the
plywood industry. From this table, we see that, as of now,
phenolic glues are being used for a portion of western interior
grades as well as for all of southern interior grades. This
table also shows that, by 1975, phenolic glues will be used
for almost all softwood plywood production. This trend toward
all phenolic glues is due to decreasing costs of phenolic resins
and problems with failures of interior plywood of inferior
quality which were exposed for short periods of time to exterior
environments. Problems such as these moved the Los Angeles
Department of Building and Safety to rule that all softwood
plywood for construction must use exterior glue
TABLE 9
CURRENT AND PROJECTED ADHESIVE CONSUMPTION
IN THE PLYWOOD INDUSTRY. J
(Million of Ponds)
Plywood Type
1965
1975
Phenolic
Urea
Protein
Phenolic
Urea
Protein
Western
Exterior
81
--
--
194
--
--
Western
Interior
14
--
104
137
--
--
Southern
Exterior
--
--
--
91
--
--
Southern
Interior
10
--
--
86
—-
—
Hardwood
--
55
--
--
120
--
TOTALS
105
55
104
508
120
Nil
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23
Innovations are being sought in the area of glue application.
One idea involves extruding the glue onto the veneer as opposed
to rolling it on with a conventional spreader. Another idea
employs a paper glue line where a dry sheet of glue is placed
between the sheets of veneer. A new process, if found, might
eliminate the glue spreader and the subsequent waste produced
from its washdown.
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WASTE CHARACTERISTICS
Waste Quantity
Measured Waste Discharge
Waste flows were measured at four plants over periods
ranging from six weeks to several months. Measurement schemes
differed at each plant according to equipment availability and
accessibility to the waste stream. These plants are referred
to by number and pertinent data are shown in Table 10.
TABLE 10
CHARACTERISTICS OF PLANTS USED IN DISCHARGE STUDY
Plant
Number
1/
1966 Production
(Sq.Ft. 3/8” Basis)
Exterior
Grade
(%)
Interior
Grade
(%)
Number
of
Spreaders
Spreader
Shifts
Per Day
Days
Worked
Per Week
1
100,000,000
50
50
4
8
5
2
135,000,000
0
100
3
9
5
3
100,000,000
25
75
4
9
5
4
70,000,000
75
25
2
6
5
At Plant Number 1, a water meter was placed in the
washwater line adjacent to one of the four glue spreaders. This
meter was read at various time intervals over a seven month period.
The meter readings were multiplied by four, and the average flows
were computed. Figure 5 shows these flows for the seven month
-------
FIGURE 5
AVERAGE GLUE WASTE FLOWS
(PLANT I)
/
Ji/J
a:
0
-J
LU
L i i
w
4
LU
>
4
30
25
20
‘5
0
5
0
2
.PM.
LI
DE M8ER JANUARY FEBRUARY MARCH APRIL MAY JUNE
966 967 1967 1967 1967 967 967
DATE
-------
27
period. The average flow for the seven month period was 12.9
gpm, and the average flow for the working days in the period
was 18.2 gpm.
At Plant Number 2, a 45-degree V-notch weir and water
level recorder were installed in a ditch between the plant
and the settling pond. This proved to be a bad arrangement as
the weir was soon plugged with glue and wood chips. The weir
was removed and an alternate plan was sought. At this plant,
the settling pond effluent was pumped into the log pond with
the pump being controlled by a set of probes. The recorder was
placed on the pond. The pond area was measured and the flow
was determined. This setup was used for 7 weeks and proved to
be the easiest to maintain. Figure 6 shows the daily average
flows for the period. The average flow for the 7 weeks was 24.4
gpm and the average flow for the working days was 30.2 gpm.
At Plant Number 3, a 60-degree V-notch weir and level
recorder were installed in a ditch located downstream from the
plant’s settling tank. This setup was used for 6 weeks and
required only minor maintenance. Figure 7 shows the daily average
flows for the period. The average flow for the period was 17.9
gpm and the average flow for the working days was 21.6 gpm.
At Plant Number 4, a 16-inch rectangular weir and level
recorder were installed in the last compartment of the plant’s
settling tank. This setup was used for 6 weeks. Figure 8 shows
the daily average flows for the period. The average flow for the
-------
FIGURE
6
DAILY AVERAGE GLUE WASTE F LOWS
(PLANT 2)
V
9
LL
2224
MAY 1961
I2l4
JUNE 1967
DATE
-------
FIGURE
7
DAILY AVERAGE GLUE WASTE FLOWS
(PLANT
DATE
3)
(9
9
LU
LU
(9
4
cr
LU
>
4
MAY 1967 JUNE 1967
-------
FIGURE 8
DAILY AVERAGE GLUE WASTE FLOWS
(PLANT 4)
DATE
LU
U i
(9
4
Ui
JUNE 1967 JULY 1967
-------
31
period was 53.2 gpm and the average flow for the working days
was 54.0 gpm.
Table 11 compiles the flow data for the four plants. As
can be seen, the average flows vary widely. This variance should
have been a result of the spreader shifts per day and the types
of glue used, but this was not found to be true. Plant Number 4,
with the fewest spreader shifts per day and the highest percentage
of exterior grade production, should have the smallest flow but,
as can be seen, its flow is much higher than flows of any of
the other three. At Plant Number 4, water use differs only
slightly on working and nonworking days, further indicating that
water is being used when spreaders are not being washed down.
The flow from Plant Number 1 was much lower than that
of any of the other three. This may be due to the manner in
which the flow was calculated. Here, actual amounts of water
used for washdown were measured, eliminating any other discharges
which may get into the waste stream farther down the line, such
as the washdown water from the glue mixing area.
At two plants, the daily maximum and minimum flows were
recorded. The average is shown in Table 11 as a percentage of the
average flow for the total days measured. The maximum for the two
plants averaged 213 percent while the minimum was 60 percent.
The average discharge for the four plants was 27.1 gpm
or 39,000 gpd. When multiplied by the 158 plants in the study
-------
( )
N)
TABLE 11
GLUE WASTE DISCHARGE MEASUREMENTS
a/
Plant
Number
Days
Measured
Average Discharge
for Days
Measured (gpm)
Average Discharge
Working Days (gpm)
Maximum
Average Daily
Discharge
(% Avg. Discharge
for total days)
A
(%
Minimum
verage Daily
Discharge
Avg. Discharge
for total days)
1
212
12.9
18.2
——
——
2
49
24.4
30.2
--
--
3
42
17.9
21.6
211
53
4
42
53.2
54.0
215
67
w
See Table 9 for
Plant Descriptions
-------
33
area, it results in a discharge of 6.2 million gallons per day
of glue waste.
In conclusion, it can be seen that, under present conditions
of inexpensive water and little concern over the destination and
pollutional effects of the waste, the flow from different plants
will vary markedly, depending upon plant practices.
Calculated Waste Discharges
Two spreader washdowns were observed, both of these
at Plant Number 1 where a water meter had been installed in the
washwater line. The first washdown required 210 gallons, took
approximately 35 minutes, and resulted in an average discharge
of 7 gpm.
Assume that 250 gallons at 7 gpm is needed to wash
down a spreader. To flush out lines or troughs, an additional
10 minutes at 7 gpm is added, giving a total of 70 gallons for
flushing. This gives a total of 320 gallons for each washdown.
The average interior plywood plant with six spreader shifts and
a washdown at the end of each shift would generate 1,920 gallons
of waste per day. To this should be added the contribution from
the washdown of glue mixing equipment. A plant making 10 batches
of glue per day and washing down its equipment after each batch
should add approximately 300-500 gpd of waste. The total glue
waste discharge should then be around 2,300 gpd per plant. A
plant in southern Oregon, which reuses its waste, has reduced its
-------
34
waste discharge to approximately 1,200 gallons per day. Here
they run five spreader shifts, rinsing after each shift, and
washing down once a day. The reuse system employed at this
plant is further explained in the section entitled TREATMENT
AND CONTROL. The 1,200 gallon per day flow measured at this
point and the conservative estimate of 2,300 gallons per day
are considerably less than the 18,500 to 76,500 gallons measured
at Plants 1 through 4. This great difference can be traced to
the fact that water is allowed to run in the waste lines when
glue is not being washed off the equipment. This practice has
been followed for one or more of the following reasons. First,
some plant personnel feel that diluting the glue waste reduces
their pollution problems. SecOnd, lines become plugged on
occasion and water is kept running in an effort to prevent this.
Third, forgetfulness and poor plant practices account for the
excess amounts of water used.
It is concluded that the glue waste discharges could
and should be reduced considerably. This could easily be done
through better in—plant practices and through the development
of new techniques such as the use of steam instead of water for
cleaning the metal parts of equipment.
The problem of plugged lines could possibly be solved
by using better line flushing techniques, minimizing waste line
lengths, using teflon coated pipes or a combination of these.
-------
35
Waste Quality
Chemical Investigations
Many different glue formulas are used by the plants in
the study area. However, the actual ingredients of the glues vary
only slightly. Table 12 lists the ingredients of typical protein,
phenolic and urea glue mixes. The pentachiorophenol or phenolic
formaldehyde resin listed under protein glue is added only when
a toxic mix is required. This toxic mix makes the glue more
resistant to biological degradation.
Because all glues could not be chemically analyzed,
typical protein, phenolic and urea glues were chosen. These
were Borden’s Casco S-230 glue, Borden’s Cascophen 31 and
a!
Borden’s Casco Resin 5H . The Casco S-230 mix contains neither
pentachlorophenol nor phenolic formaldehyde resin. The
ingredients of these glues were obtained from the producing
company and the glues were mixed in the laboratory. These
prepared glues were then chemically analyzed. Table 13 lists the
results of these analyses. The phenolic glue with a COD of 653,000
mg/kg and a phenol concentration of 514 mg/kg is the strongest and
most toxic of the three glues analyzed. Whereas, the phenolic glue
has a high COD and phenolic concentration, it is the most deficient
in nutrients, having nitrogen and phosphorus concentrations of
1,200 mg/kg and 120 mg/kg, respectively.
a!
Use of product and company names is for identification only and
does not constitute endorsement by the U. S. Department of the
Interior or the Federal Water Pollution Control Administration.
-------
36
TABLE 12
INGREDIENTS OF TYPICAL PROTEIN, PHENOLIC & UREA GLUE MIXES
Protein Glue _ for _ Interior Grade Plywood
Water
Dried Blood
Soya Flour
Lime
Sodium Silicate
Caustic Soda
Formaldehyde Doner for Thickening
Pentachiorophenol b/
Phenolic Formaldehyde Resin b/
Phenolic Glue for Exterior Grade Plywood
Water
Furafi l-
Wheat Flour
Phenolic Formaldehyde Resin
Caustic Soda
Soda Ash
Urea Glue for Hardwood Plywood
Water
Defoamer
Extender (Wheat Flour)
Urea Formaldehyde Resin
a!
Residue from furfural extraction of corn cobs and oat hulls
b/
— May be added to produce a toxic glue
-------
TABLE 13
AVERAGE CHEMICAL ANALYSIS OF PLYWOOD GLUE
- ./
Analysis and Units Phenolic Glue Protein Glue Urea Glue
COD, mg/kg 653,000 177,000 421,000
BOD, mg/kg 88,000 195,000
TOC, mg/kg 176,000 52,000 90,000
Total Phosphate, mg/kg as P 120 260 756
Total Kjeldahl Nitrogen, mg/kg as N 1,200 12,000 21,300
Phenols, jig/kg 514,000 1 ,810
Suspended Solids, mg/kg 92,000 59,000 346,000
Dissolved Solids, mg/kg 305,000 118,000 204,000
Total Solids, mg/kg 397,000 177,000 550,000
Total Volatile Suspended Solids, mg/kg 84,000 34,000 346,000
Total Volatile Solids, mg/kg 172,000 137,000 550,000
1 Borden’s Cascopheri 31 which is similar to Borden’s Cascophen 382
WBordenhs Casco S-230
- Borden’s Casco Resin 5H
-------
38
Pollutional Effects
Stream Survey . A biological survey of Anderson
Creek, Tillamook County, Oregon, was undertaken to more fully
assess the impact of plywood glue waste on a small stream.
Anderson Creek, a small tributary to the Tillamook
River, is approximately three miles long. This stream was
selected because of its accessibility, size, and absence of
other waste streams. For the first half mile of its length,
it is an intermittent stream, flowing in the bottom of a large
ditch. The creek is shallow, with a maximum depth of approximately
three feet. It flows through a marshy area in its lower reaches.
The original mouth of the creek is now blocked off and the last
1,000 feet of flow is through a man-made channel. Large check
valves at the end of the channel prevent the Tillamook River
from back-flowing into Anderson Creek during high tides. The
primary source of water in the upper reaches appears to be
surface drainage from an adjacent airstrip, groundwater seepage,
and the discharge from the plywood plant. Flow measurements in
the creek below the waste outfall in the late summer ranged from
120 to 220 gpm. The Oregon State Water Resources Board determined
that the minimum flow necessary to maintain fish life was 0.4 cfs
(180 gpm) J
-------
39
The plywood plant, referred to earlier as Plant Number
discharges its waste into Anderson Creek about 2.2 miles
upstream from its mouth. The waste flow from the plant averages
12.9 gpm.
Ten sampling stations were established on Anderson
Creek. As shown in Figure 9, four were upstream and six were
downstream from the waste outfall. Three elements of the
Anderson Creek biota were sampled: benthic fauna, planktonic
algae and attached algae. Observations of the water surface
and stream bottom were also noted, as well as occasional
determinations for dissolved oxygen and pH. The results of
the Anderson Creek survey showed that the creek supported a
fairly well balanced aquatic community upstream from the waste
outfall. The introduction of the waste, however, severely
degraded the stream as indicated by studies of the benthic fauna
and phytoplankton flora.
A quantitative bottom survey revealed that benthic
animals commonly associated with clean water conditions were
absent at sampling stations established downstream from the
outfall. The ber,thic forms which colonized artificial substrate
samplers, placed both upstream and downstream from the outfall
for six week intervals during a six month period, consistently
iInformation regarding this plant can be found in Table 10.
-------
9
ANDERSON
CREEK
CREEK
OUTFALL
0 1000
SCALE IN FEET
‘I
‘
FIGURE 9. ANDERSON
CREEIK SAMPLING
SITES
-------
41
revealed severe degradation. There were some indications of
stream recovery at the mouth of the creek, about 2.2 miles
below the outfall.
The phytoplankton populations were greatly reduced
by the volumes of incoming waste. Also, downstream from the
outfall , they included certain forms commonly associated with
polluted conditions.
Observations on the physical appearance of the
stream showed badly polluted conditions downstream from the
plywood plant. Obnoxious slime growths, dark, foamy water and
foul odors were common. There was also some evidence of
oxygen depletion due to the wastes. Table 14 lists some of
the physical conditions observed at the ten sampling stations.
The presence of untreated plywood glue wastes creates
an unhealthy climate for the normal inhabitants of a stream
bottom. These organisms are important links in the aquatic
life food chain and their absence or depletion can effectively
eliminate a stream’s ability to support a resident fish
population. The associated slime growths can have a very
deleterious effect on fish spawning beds.
-------
TABLE 14
ANDERSON CREEK - PHYSICAL OBSERVATIONS
.
Approx. ——
Distance
Depth
Width
Below
Station Ft.
Ft.
Outfall, Mi. Bottom Type Remarks
AC—i 2.5—3 6-8 Coarse Sand, Silt, Small Pool. Abundant reeds and
Wood Fibers emergent vegetation.
AC—2 .75 2-3 Coarse Sand, Silt Much green filamentous algae on
bottom. Abundant vegetation.
AC-3 2-3 6-8 Silt, Coarse Sand Small pool. Much vegetation and
green filamentous algae.
AC-4 .5-.75 2 --- Gravel, Rock Riffle.
AC-5 .5 6 .03 Gravel, Rock Riffle. Bottom slime-covered, foul
odor. Water red to black and
foamy in summer. Clearer in Fall.
AC-6 .75 5 .10 Gravel, Rock Bottom slime-covered. Oil slick
and foul odor in Spring. Abundant
filamentous algae on banks.
AC-7 .75 4 .22 Gravel, Rock Bottom slime-covered. Long
strands Spjhaerotilus in Spring.
Black oily substance on banks.
AC-8 1-2 6-12 .34 Gravel, Rock Riffle. Abundant vegetation at
shore. Sphaerotilus strands, oil
slick. Water dark.
AC-9 1-2 50 1.13 Ooze, Silt Marshy, profuse vegetation, almost
stagnant.
AC-b 3 10—12 2.23 Clay, Silt No vegetation, steep banks. Water dark.
-------
43
Toxicity Studies . A brief series of acute toxicity
bioassays was conducted to further evaluate the characteristics
of plywood glue wastes. Three glues were tested to compare
their relative toxicity.
The toxicity bioassay is designed to test acute
toxicity only. It is essentially a test in which a certain
number of organisms are exposed to various concentrations of
a waste for given periods of time. The results are often
expressed in terms of the median tolerance limit (TLm)•
The methods used in conducting the bioassays were
essentially those described by Douderoff et a]., and Standard
Methods , with minor modifications - -- ’. Static or non-flowing
tests were conducted and, although certainly not representative
of stream conditions, were believed adequate for the screening
of relative toxicity.
Three species of fish were used: young guppies, ( Poecilia
reticulata) , chinook salmon fry ( Oncorhynchus tshawytscha ) and
coho salmon fry ( Oncorbynchus kisutch) . Guppies were used in
the majority of tests in order to have a uniform test organism
and because of handling ease.
In a system of daily solution renewal on guppies, the
median tolerance limits for 96 hours for Casco S-230, an interior
glue, averaged 4,500 mg/l while Cascophen 382, an exterior glue,
averaged 1,140 mg/i. Guppies tested in Cascophen 31, also an
-------
-p.
-p.
TABLE 15
ACUTE TOXICITY CHARACTERISTICS OF VARIOUS PLYWOOD GLUES
No.
Glue Fish Tests
Critical
Range,
Concentration
mg/i
96
hour U , m
m
Glue Solution
Age, Days Renewal
Avg.
Range
Casco S-23O Guppy 1 1,800-10,000 7,200 Fresh None
Guppy 2 1,800-10,000 4,500 4,200—4,800 Fresh Daily
Guppy 2 1,800-10,000 2,650 2,400-2,900 34-36 Daily
Cascophen 382 Guppy 2 650- 2,400 1 ,325 1 ,200-l ,400 48-55 None
Guppy 3 650- 2,400 1,140 830-1,400 48-76 Daily
Cascophen 31* Guppy 1 280- 1,000 500 14 Daily
Guppy 1 320- l,UOO 700 150 None
Chinook 1 100- 230 140 150 None
*Fjrst Batch
-------
45
exterior glue, had a 96 hour TLm of 500 mg/i.
In a non-renewal system, the exterior glues exhibited
a much lower decrease in toxicity than the interior glue. This
would indicate a more persistent form of toxicity. The interior
glue seemed to increase in toxicity after a long-term storage,
in contrast to the exterior glues. A comparison test between
young guppies and chinook salmon fry in a non-renewal system
using Cascophen 31 revealed 96 hour TLm values of 700 mg/i for
the guppies and only 140 mg/i for the salmon. Acute toxicity
characteristics of the various plywood glues studies can be
found in Table 15.
The State of Washington tested wastewaters from
several plywood glues on various species of salmon in both fresh
and salt water 1 . A phenolic glue similar in composition to
Cascophen 31 and Cascophen 382 was tested in aerated, non-renewed
fresh water on chinook salmon weighing about 2 gnis. The apparent
tolerance level at 72 hours was reported to be 450 - 950 ppm.
The apparent 72 hour tolerance level of the chinook fry tested
at the Pacific Northwest Water Laboratory with Cascophen 31,
in a non-aerated, non-renewal system, was 100 - 180 mg/i.
As stated earlier, the above tests were undertaken to
determine relative toxicity. To determine the chronic effects
of plywood glue to endemic fish, long-term studies should be
undertaken. These studies, utilizing a continuous flow-through
system, would involve the evaluation of untreated and treated
-------
46
glue wastewaters. It might also be advisable to conduct field
studies using live boxes above and below typical glue waste
outfalls.
-------
TREATMENT AND CONTROL
Nlethods in Use
Many different disposal methods for glue waste are in
use at the present time. The methods vary from discharging
untreated waste directly to streams, to systems involving
municipal treatment plants. Table 16 lists 23 different
schemes used by the 106 plants surveyed. As can be seen, 77
plants employ some type of settling tank or pond. The settling
tanks commonly consist of one or more 1,000-gallon septic tanks.
These settling devices remove some of the glue solids and the
wood chips. Table 17 lists the chemical analyses of the settled
effluent for three of the plants used in the discharge survey 1 .
Comparison of Table 13 and Table 17 shows a significant increase
in the dissolved solids/suspended solids ratio after the settling
operation, indicating a reduction of suspended solids. A similar
comparison also shows little reduction in phenols, phosphates,
and total kjeldahl nitrogen.
The removal of suspended solids is further evidenced by
the filling of settling devices, necessitating their periodic
clean-out. This clean-out is needed every 1 to 3 months,
depending upon the tank size, number of washdowns, and types of
glues used. In these tanks and ponds, lack of proper maintenance
1 Information regarding the three plants can be found in Table 10.
-------
48
TABLE 16
DISPOSAL METHOD OF PLANTS IN SURVEY
Number of Pl ants Using System
( j
c:
.r-
0
-4- )
S.-
o
0
C C C
4-
0
r 0 •
J
q-
4 ) O C
.
—
Disposal System
(_)
(‘
o
‘-4
= t j cj
o s-
C)
i—
c
F
Field Spreading a
Log Pond (N. 0.)—
Log Pond, Field Spreading
Log Pond, S. L. R. 0. D/
Municipal Sewer
Settling Tank,
Settling Tank,
Settling Tank,
Settling Tank,
Settling Tank,
Settling Tank,
Settling Tank,
Spreading
Settling Tank,
Settling Tank,
S. L. R. 0.
Settling Tank,
Settling Tank,
S. L. R. 0.
Other C l
Log Pond (N. 0. )
S. L. R. 0.
Waste Burner
(Further Disposal Unknown)
Field Spreading
Log Pond (N. 0.)
Log Pond, Field Spreading
Log Pond, S. L. R. 0.
Municipal Sewer
Settling Pond (N. 0.)
Settling Pond, Field
Settling Pond, Slough
Settling Pond,
1
2
3
1
1
5
7
1 1
1 1
1
1
2
8 12
20
1 1 2
4 5 11
1 1
a!
b/
Non-overfi ow
Stream, Lake, River or Ocean
Settling Pond (N. 0.)
Settling Pond,
Settling Pond,
Settling Pond,
Settling Tank,
1
1
1
1
1
2
1
2
4
5
5
3
1
1
28
2
4
1
3
14
1 8
3
1 2
1
4 14
3 7
1 5
1
4
5
S. L. R. 0.
Waste Burner
Waste is put in drums and hauled to land disposal
-------
49
TABLE 17
CHEMICAL ANALYSIS OF SETTLED EFFLUENT
/
/
& /
#2
#3
#4
Analysis & Units P1
ant
P1
ant
P1
ant
pH 11.6 9.4 10.8
COD, mg/i 1814 1917 1621
TOC, mg/i 772 723 540
Total Phosphate, mg/i 15 9 12
Total Kjeldahl Nitrogen, mg/i 110 64 3
Phenol , ig/1 1667 1790 222
Suspended Solids, mg/i 148 356 330
Dissolved Solids, mg/i 1479 1458 790
Total Solids, mg/i 1627 1814 1120
Total Volatile Suspended Solids, mg/i 125 338 322
Total Volatile Solids, mg/i 1122 1267 919
a!
Average of 2 grab samples
b/
Average of 3, 24-hour composite samples
c/
Average of 2, 24-hour composite samples
-------
50
leads to poor efficiencies and subsequent problems. Usually,
these tanks are not cleaned until they are completely filled,
resulting in zero or even negative efficiencies.
Table 16 also shows that 18 plants employ some type of
non-overflow system to dispose of their waste. In such a
system, the rates of evaporation and infiltration exceed that
of the waste input. Because of the plugging nature of glue
solids, evaporation probably accounts for most of the moisture
lost.
Twelve of the plants surveyed dispose of their waste in
municipal treatment systems. Wood chips and glue solids contained
in these wastes plug the municipal sewers and overload treatment
plant screening and grit removal processes. The high pH of the
waste may raise the plant’s pH to the point that problems
arise with secondary and digestion processes. Adjustment of
pH and the use of settling tanks or ponds should make the waste
amenable to conventional waste treatment. The settling would also
help dampen out any slugs of toxic materials, such as phenolic
compounds, which can upset the balance of a biological system.
Eleven of the plants listed in Table 16 discharge their
wastes with no treatment whatever. The majority of these plants
are located on large bodies of water such as Puget Sound, the
Pacific Ocean, or the Columbia River.
-------
51
Biological Treatment Studies
Biological treatment studies were undertaken to determine
the feasibility of this method for the treatment of plywood
glue wastes. A secondary purpose was to determine what problems,
if any, might occur if this type of waste were discharged into
a municipal treatment system. The studies were conducted on
a pilot plant scale and parameters such as nutrient addition,
BUD loadings and efficiencies were investigated.
Two different pilot plant systems were used in the studies.
Most of the work was done in a conventional activated sludge
9/
system patterned after one used by Ettinger. The system which
is shown in Figure 10 included primary sedimentation, aeration,
secondary sedimentation and sludge recycle. Pertinent data on the
system are listed in Figure 10. Figure 11 depicts these systems
as they were used at the Pacific Northwest Water Laboratory.
The second system was used only on the urea glue waste. This
was a complete mix system consisting of aeration, sedimentation,
and sludge recycle. The same aeration tank, minus the baffles,
was used as in the first system described. The aeration period
of the second system was maintained at five days. A special
secondary settler was constructed which had a detention time of
two hours.
Protein Glue Studies
Studies involving biological treatment of protein glue
were conducted for a three month period. During this time, the
-------
FEE Q
METERING
PUMP
PRIMARY SETTLER
VOLUME -3.5GAL( 13 1 2L)
DETENTION TIME —2HRS. AT FEED OF IOBML/MIN.
*- TAP WATER
SPIRAL FLOW AERATION
TANK VOLUME-27,2 GAL
AERATION TIME- 16 HRS
AT FEED OF lOB ML/MIN.
SECONDARY SETTLER
VOLUME - 5 6 GAL.C 21 L.)
DETTIME-3 1 27 HRS.
AT FEED OF lOB ML/MIN.
RETUS U -
PUMP
FINAL EFFLUENT
SLUDGE TO
WASTE
FIGURE tO. ACTIVATED SLUDGE PILOT PLANT
FLOW DIAGRAM
( 102L)
ii
SLUDGE TO WASTE
-------
FIGURE 11.
ACTIVATED SLUDGE PILOT PLANTS
I
7 J
-------
54
BOD loading was varied from 5 to 52 lb/lOO MLSS. Three
different detention times were studies with the majority of the
work done at 16 hours. Table 18 lists some of the data compiled
from the three months of operation. As can be noted, excellent
removals of BOD and suspended solids were attained at all
detention times and loadings. Also, the majority of removal
took place in the secondary system.
The protein glue pilot plant was started up using
mixed liquor from studies done with a feed of dry milk. No
problems were encountered using this method and good removals
were experienced from the beginning. Inorganic nutrient additions
were not deemed necessary because of the levels present in the
glue.
For the protein glue, correlations were drawn between
the BOD and COD’s of the influent and effluent. Figures 12 and 13
show the results of these comparisons. The equations of the
calculated lines of best fit and the correlation coefficient are
as follows:
Influent COD 77.6 + l.3(Influent BOD) It .97
Effluent COD 39.9 + 1.8(Effluent BOD) It .89
A relationship was also drawn up relating the influence of
loading on BOD removal, as plotted in Figure 14. The calculated
relation between loading and removal obtained from the data was
-------
55
TABLE 18
a/
BIOLOGICAL TREATMENT OF PROTEIN GLUE
% Removal
Detention
(Hours
Primary & Secondary Secondary
Period Treatment Treatment
) Lb BOD/100 lb MLSS BUD SS BUD SS
16 5.8 93 50 91
16 10.6 93 50 91
16 12.4 94 - 93
16 13.3 93 87 93
16 13.5 91 76 90
16 14.2 96 96 92 87
16 16.3 96 83 95 57
16 16.6 98 97 98 90
16 20.1 97 - 97
16 20.5 96 87 95
16 22.0 95 93 94 90
16 23.6 97 97 97 89
16 25.3 96 - 95
16 26.4 97 98 97 92
16 37.7 95 94 95 86
16 41.2 95 95 95 86
12 39.4 86 93 83 93
12 57.2 95 90 94 87
8 52.0 91 85 91 78
a!
Borden’s Casco S-230
-------
o tOO 200 300 400 500 600 700 600 900 K)00
INFLUENT BODI MG/LITER
FIGURE 12. BOD VS. COD FOR BORDEN’S
CASCO S-230
1500
1400
1300
1200
1100
.
S
I
S
cr
w
F—
-J
a
8
w
3
-J
lL
z
300
S
INF. COD = 77.6+1.3 C INF. BOD)
200
tOO
0
-------
ISO
/
170-
160-
150-
140--
I
130-
lao- -
S
hO--
100--
-J
90-.
o
-SO-
0
0
U 70-
I—
z
U 6 r ..
D
-J
i i EFF.COD =39.9+I.8(EFF. BOD)
40-
I
30- -
20-
ID-
0
0 10 20 30 40 50 60 70 80 90 100
EFFLUENT BOD 1 MG/ LITER
FIGURE 13. BODVS. COD FOR BORDENS CASCO S-230
PROTEIN GLUE
-------
.6
.5--
.4-
.3-
.2-
. 1
0
X-- NOT USED
x-
0 10 20
L * BOD/
FIGURE 14. INFLUENCE OF
FOR BORDENS
l0O4 MLSS
LOADING ON BOD REMOVAL
CASCO S-230 PROTEIN
GLUE
a
N
0
U i
>
0
Ui
a:
a
0
p
a:
I
R=(.0 12)L-. 109
I2 L 50
,&,= .97
30
40
50
-------
59
as follows:
lb BOD Removed/Day = (.012) lb BOD/l00 lb MLSS - .109
12 lb BOD/100 lb MLSS 50
= •97
Although good removals were obtained on the protein
glue, some operational problems were encountered. The largest
problem was with Sphaerotilus growth in the mixed liquor which
bulked the sludge and caused a considerable problem in settling.
This problem was solved by raising the pEl of the aeration
tank to 11.0 with calcium hydroxide (Ca(OH) 2 ) which killed all
the biological life. The pH slowly subsided and in approximately
10 days, the biological life, minus the Sphaerotilus , had returned.
The problem occurred twice during the operation with the protein
glue.
By employing a conventional activated sludge system,
protein glues were efficiently treated, and it is probable that
other forms of biological treatment would prove feasible.
Problems encountered appear to be no worse than those in a
domestic system.
Phenol Ic G’ue Studies
Studies involving the biological treatment of phenolic
glue were conducted for a four month period. At the end of this
time, the studies were discontinued as no results of any
consequence had been attained.
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60
The pilot plant at start-up utilized some of the mixed
liquor from the protein glue aeration tank, at a loading of
5 lb COD/lOO lb MLSS. Because the phenolic glue was low in
inorganic nutrients, these were added in the forms of animonium
hydroxide (NH 4 OH) and phosphoric acid (H 3 P0 4 ) to bring the
COD/N/P ratio up to 100/5/1 . For a short time, the system
appeared to be operating normally. However, after three or
four weeks, the solids began to drop off in the aeration tank.
The problems associated with the pilot plant were
complicated in that laboratory BOD data could not be obtained
on the phenolic glue. The phenol concentrations, while quite
high (514 mg/kg), were still in the approximate range of 500 mg/l
found by McKinney et al. to be biologically treatable with
proper acclimation- 1 1 . Special seed acclimazation studies were
performed to no avail.
The plant was started up again using a mixed feed of
protein and phenolic glue. This approach worked for a longer
time than the first, but it too eventually failed.
A third attempt was made. This time raw sewage,
bottom muds from an outfall near a phenolic waste discharge, and
mixed liquor from the protein glue aeration tank were used in an
effort to acclimate a group of organisms to degrade the glue.
This, too, ended like the others.
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61
In conclusion, all attempts to acclimate the biological
system to treat phenolic glue resulted in failure. If a system
could, in fact, be acclimatized, the operational problems
involved would require skilled supervision which, in most cases,
would not be provided.
Urea Glue Studies
Studies involving urea glue were conducted on two
different activated sludge systems, the second a result of
special pilot plant studies done in connection with a Federal
demonstration grant.
The urea glue studies were started when the protein
glue work was finished. Mixed liquor used for the protein glue
was fed into the urea waste and no problems were encountered.
Inorganic nutrient levels in the urea glue were adequate so no
nutrients were added. After running one and one-half months at
16 hours detention time, the second system, with a detention
time of five days, was initiated. The system, run at 16 hour
detention time, included both primary and secondary treatment,
whereas secondary treatment only was used in the 5-day detention
time study.
Table 19 lists the results of the urea glue tests
to date. As can be seen, excellent BOD and suspended solids
removals were achieved with both systems. The BOD removals
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62
BIOLOGICAL
TABLE 19
a/
TREATMENT OF UREA GLUE
Loadings
Detention Period Lb BOD/100 lb MLSS
%
BOD
b/
Removal
SS
16 hours 10.3 81 72
16 hours 10.7 84 91
16 hours 14.7 89 97
16 hours 17.9 90 92
5 days 4.3 90 93
5 days 23.3 98 98
5 days 24.9 94 97
5 days 28.4 94 96
5 days 30.0 87 87
5 days 30.7 93 98
5 days 44.8 96 98
a!
Borden’s Casco Resin 5H
b/
— 16 hour; Primary & Secondary
5 Day; Secondary
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63
ranged from 81 to 98 percent and those for suspended solids
from 72 to 98 percent.
The only problem encountered was fermentation,
believed to have been caused by allowing the feed to set too
long before a new batch was made. To remedy this situation,
feed was prepared each day. The plant was dumped and started
up again using mixed liquor from a municipal treatment plant.
Within a week and a half, the mixed liquor in the aeration
tank was over 2,000 mg/i which indicates that urea glue wastes
are amenable to biological treatment.
Solids production was very high for the biological
system used and preliminary figures indicate that the cost
and problems involved in the solids handling phase of treatment
may make the system prohibitive.
Physical-Chemical Treatment Studies
Neutral i zation
Due to the high pH of both the phenolic and protein
glue, neutralization was investigated. Neutralization was
envisioned not only as a possible complete treatment process,
but also as a necessary pretreatment step to subsequent
processes or discharge to municipal treatment systems or
receiving waters. The investigation of the process of neutral-
ization involved preparing titration curves for the various
glue wastes plus bench scale studies.
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64
Figure 15 shows titration curves for the alkaline,
phenolic and protein glues while Figure 16 is for the slightly
acidic urea glue. As can be seen, the phenolic and protein
glues are highly buffered, requiring large amounts of acidity
for neutralization. The urea glue, by comparison, is only
slightly acid and, therefore, was not studied further.
Bench scale studies were conducted to evaluate such
parameters as COD and TOC reduction and sludge production.
These studies were conducted by using a specified concentration
of glue in water. Equal volumes of this mixture were placed
in beakers to which varying amounts of neutralizing agent were
added. The solutions were mixed at 90 RPM’s for five minutes
and allowed to settle for four hours after which samples of
the supernatant and sludge were withdrawn for analysis. Three
different neutralizing agents: alum (A1 2 (S0 4 ) 3 181-1 2 0), sulfuric
acid (H 2 S0 4 ), and hydrochloric acid (HC1) were tested on the
protein glue, while only sulfuric acid and alum were tested
on the phenolic glue. Figures 17 and 18 show the results of
these investigations for the protein and phenolic glues,
respectively. In these figures, COD or TOC per gram of glue
for the supernatant is plotted against pH. Optimum dosages
of chemical were arbitrarily chosen where minimum TOC or COD
in the supernatant was attained with minimum chemical added.
These optimum treatment dosage points are shown by X’s on the
-------
BORDEN’S
BORDEN’S
CASCOPHEN 31
CASCO
0 I 2 34 5 6 7 6 9
S-230
10 II 12 13 14 15 16 17
ML ION H 2 S0 4 /GM.GLUE
15. TITRATION CURVES FOR PHENOLJC& PROTEIN GLUE
12
II
I0
9
S
7
6
a-
5
4
3
2
A
)
B
)
FIGURE
-------
J ‘ I
I I
T I
p p p I p i i
.7 .6 .5 .4 .3 .2 .1 0 .1 .2 .3 .4 .5 .6 .7
NQOH/GM. GLUE ML ION HzS0 4 /GM. GLUE
ML l.ON
FIGURE 16. TITRA11ON CURVE FOR HARDWOOD GLUE
12
II
I0
.7
I
0 •
Il
9
8-
.5-
.4-
.3
2
A)
- BORDEN’S C.ASCO RESIN 5 H
I I I I
I I I
I I I I I
-------
Co D OR TOCI MG / GM GLU E
FIGURE 17 COD AND TOC OF SUPERNATANT VS. pH FOR
PROTEIN GLUE
I0
9
B
7
6
5
4
3
2
I
a-
0 10 20 30 40 50 €0 70 80 90 100 110 120 130140
-------
0 100 200 300 400 500
CODS MG/GM. GLUE
FIGURE 18. COD OF SUPERNATANT
GLUE
VS.pH FOR PHENOUC
‘I
9
B
5
4
7
a-
6
3
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69
curves. As can be seen, most of the points are very close to
a pH of 7.0. Tables 20 and 21 compare the various neutralizing
agents at the optimum dosages. For the protein glue, H 2 S0 4 has
the cheapest chemical cost and produces the best supernatant.
For the phenolic glue, alum produces the best supernatant, but H 2 S0 4
produces less sludge and has a lower chemical cost. Virtually,
100 percent removal of COD was obtained by neutralization of protein
or phenolic glue with either acid or alum. When alum was used on
the phenolic glue, it was evident that some flocculation was taking
place as well as neutralization. This flocculation accounts for
the greater removal of COD and for the increased sludge production.
It is emphasized that, in the final analysis, chemical costs may
be small -in comparison to other costs such as these associated with
chemical feeding and sludge handling.
Table 21 shows that large volumes of sludge are produced
from the neutralization of phenolic glue. For acid neutralization,
40 ml of sludge/gm of glue (.65 ft 3 /lb glue) were produced as
compared to 60 nil/gm glue (.98 ft 3 /lb glue) for alum neutralization.
These large amounts of sludge could present many problems, especially
if they proved hard or expensive to dewater.
From the standpoint of producing a dischargeable effluent,
neutralization or neutralization-flocculation has proved a feasible
process. However, problems associated with the great amount of
sludge produced make other alternative processes more attractive.
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70
TABLE 20
a/
NEUTRALIZATION OF PROTEIN GLUE WASTE
A
(iN
cid Alum
H 2 S0 4 ) (iN A1 2 (S0 4 ) 3 .18H 2 0)
A
(iN
cid
HC1)
—
Optimum Treatment
Dosage, mi/gm glue 0.63 0.67 0.62
b/
COD supn’t, mg/gm glue 19.5 26.0
TOG, supn’t, mg/gm
glue C/ 3.2 9.0
pH 7 .9 6.9 7.6
Cost of Chemicals!
100 lb glue $.16 $.36 $.34
a!
Borden’s Casco S-230
b!
lnitial COD, 176,000 mg/gm glue
C!
Initial TOG, 52,000 mg/gm glue
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71
TABLE 21
a/
ALUM VS H 2 S0 4 FOR NEUTRALIZATION OF PHENOLIC GLUE WASTE
Acid Alum
(iN H 2 S0 4 ) (iN Al 2 (S0 4 ) 3 18H 2 0)
Optimum Treatment Dosage,
mi/gm glue 1.38 1.40
b/
COD supn’t mg/gm glue 67.0 50.0
pH 6.8 7.4
Total gms solids produced!
gm glue 0.24 0.46
Total Volume sludge, mi/gm
glue 40.0 60.0
Cost of chemicals/lOO lb glue $.35 $.75
Borden’s Cascophen 31
b/
lnitial COD, 653,000 mg/gm glue
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72
Incineration of Waste
Due to the low volume of waste, high organic content
of the waste, and availability of existing sources of heat,
disposal by incineration offers a promising solution to the glue
waste problem.
Three of the plants surveyed are at the present time
using waste burners to dispose of their glue wastes. Because
these metal uteepeeshl burn rather inefficiently and their use may
be prohibited in the near future, some other means of incinerating
is needed. One large corporation is considering using its Dutch
ovens which burn at temperatures of 1800 to 2000°F. If sander
dust is burned, the temperature can go as high as 2500°F.
An ash test was made on samples of protein and phenolic
glue. These were run at 600°C (1112°F) and at 1000°C (1832°F).
The results of these tests are shown in Table 22. The tests
indicated that at 1000°C (1832°F) very little ash remains. The
protein glue produced 4.12 and 23.40 percent ash, based upon wet
and dry weight, respectively, at 1000°C (1832°F). The phenolic
glue produced 612 and 15.76 percent ash, based upon the wet and
dry weight, respectively, at 1000°C (1832°F). A plant with three
spreaders running six spreader shifts per day and washing down at
each shift would generate about 12 pounds of ash per day. This is
a si al1 percentage of the total ash produced in a furnace of the
type now used at plywood mills.
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73
TABLE 22
INCINERATION TEST FOR PHENOLIC, PROTEIN AND UREA GLUE
Ba
Glue % A
sed on Wet Weight
sh @ 600°C % Ash
of Glue
@ 1000°C
Based
% Ash
on Dry
@ 600°C
Weight
% Ash
Glue Solids
@ 1000°C
a!
Phenolic
4.58
4.12
26.08
23.40
b/
Protein
13.37
6.12
34.48
15.76
C!
Urea
Nil
Nil
Nil
Nil
a!
Borden’s
Cascophen 382
b/
— Borden’s
Casco S-230
C’
Borden’s
Casco Resin 5H
Examining Table 13, one sees that incineration offers
the best potential for urea glue waste disposal as the solids are
nearly 100 percent volatile. For this reason, the percent ash values
in Table 22 are reported as nil.
If incineration is to be used as a disposal method, certain
problems must be overcome. One of the biggest of these problems is
in transporting the glue waste from the spreaders to the incinerator.
Plugging must be minimized so that maintenance of pumps and lines
is low.
Another problem lies in injecting the waste into the
furnace. Many attempts to use spray nozzles have failed due to
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74
plugging problems. The best alternative seems to be in applying
the waste to the hog fuel before it is burned.
Questions involving potential air pollution and scaling
of burners must also be answered before incineration is an
acceptable method of disposal.
Wastewater Reuse
A southern Oregon plywood plant has implemented a reuse
system which has successfully solved its waste disposal problems.
This plant has two spreaders which run for five spreader shifts
per day. Annual production is around 100,000 square feet
(3/8-inch basis) all of which is exterior grade. Seventeen to
18 batches of glue per day are mixed requiring 535 pounds of
water per batch for an approximated total of 1,150 gallons.
Spreaders at the plant are rinsed once per shift and washed
once per day. The mix tanks are scraped but not washed before
each batch mix. Lines from the glue storage tank to the spreaders
are never flushed out and no problems have resulted in three and
one-half years of operation. The plant superintendent claims
that by excluding air from these lines they will never plug.
Before rinsing or washing down the spreaders, all excess glue is
scraped from the rollers and the pan. Very little water is then
required to wash off what remains. Instead of the common 1- or
1 1/2—inch water line for washing, a 1/2— or 3/4—inch hose has
been found to be adequate. Using these practices, the total waste
volume runs less than 1,150 gallons per day.
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75
The waste flows from the spreaders to a 1 ,000 to 2,000
gallon settling tank. Before entering the tank, the waste drops
through a 1/8—inch screen which removes the chips, knots and larger
glue solids. These solids are periodically dumped into a hopper
to drain further before they are burned. The solids which settle
in the tank are pumped out on the average of every two months.
These solids are disposed of at a sanitary landfill. A 1/2-
horsepower irrigation pump pumps the liquid from the tank through
a 1—inch plastic line to a 1,000-gallon storage tank located on
the roof of the plant directly over the glue mixing area. Flat
valves in the two tanks control the operation of the pump. Steam
is used in winter to keep the waste in the roof storage tank from
freezing. However, this problem could be overcome by locating the
tank inside the plant. Figure 19 is a schematic drawing of the
waste reuse system. Figure 20 shows a picture of the settling
tank and roof storage tank.
The cost of the system, minus the settling basin and lines
to it from the spreaders, was estimated at $500. Besides solving
the waste problem, the company actually received other benefits
from their system. First, they have reduced the amount of caustic
needed in making their glue, due to the caustic returned in the
waste. Secondly, they have increased the resin content of their
mix, thus producing a better adhesive. They have also increased
the viscosity of their glue, much to the surprise of the glue
manufacturer.
-------
p
I PLASTIC
LINE
* MESH SCREEN TO
REMOVE CHIPS 1 ETC.
HP IRRIGATION PUMP
CONTROLLED BY FLOAT
VALVES IN SETTLING
TANKS. HOLDING TANK
1Q00 GALLON
HOLDING TANK
GLUE SPREADER
PAN
I ’
.1
TANK
LUDGE PUMPED OUT
AND TAKEN TO LANDFILL
: .
FIGURE 19. REUSE SYSTEM FLOW DIAGRAM
-------
FIGURE 20. REUSE SYSTEM SHOWING SETTLING TANK,
PUMP AND ROOF STORAGE TANK
The system might be further improved by using some steam for
cleaning metal parts and teflon-coated glue pans for easier clean-out.
Reuse, as employed at this plant, could be utilized at any
plant where phenolic glues are used. Reuse systems for wastes
from protein and urea glue are not being employed at the present
time, but should be tried. If the plant uses different glues, the
wastes must be kept separate if reuse is to be practiced. Important
in this southern Oregon plant’s reuse of its wastewater is the great
reduction in volume of washwater that can be achieved through better
in-plant practices.
-------
BIBLIOGRAPHY
1. 1967 Plywood and Board roducts Directory . Forest Industries,
Portland, Oregon, 1967.
2. Sherman, D. F., “Plywood Weathers Rough ‘66 —- Yet Scores
Notable Gains.” Forest Industries, 94 (1), 1967, PP. 42—45.
3. Anonymous, “Los Angeles Story Spotlights Problem of Non-
Conformance.’ 1 Forest Industries, 93 (1), 1966, p. 58.
4. Anonymous, “Final Report on Preliminary Technical-Economic
Evaluation of Wood Adhesives Based on Soluble Animal
Protein, Soy Flour, and Dialdehyde Starch.” Battelle
Memorial Institute, Columbus, Ohio, 1967.
5. Anonymous, “North Coast Basin.” Oregon State Water Resources
Board, Salem, Oregon, 1961.
6. Douderoff, P., Anderson, B. G., Burdick, G. E., Gaitsoff, P. S.,
Hart, W. B., Patrick, R., Strong, E. R., Surber, E. W.,
and Van Horn, W. M., “Bioassay Methods for the Evaluation
of Acute Toxicity of Industrial Wastes to Fish.” Sewage
and Industrial Wastes , Vol. 23, No. 11, 1951, pp. 1380-
1397.
7. American Public Health Association, “Bioassay Method for the
Evaluation of Acute Toxicity of Industrial Wastewaters
and Other Substances to Fish.” Standard Methods for the
Examination of Water and Wastewater , 12th ed., American
Public Health Association, New York, 1965, PP. 545-563.
8. Holland, 6. A., Lasater, J. E., Newmann, E. D., and Eldridge,
W. E., “Toxic Effects of Organic and Inorganic Pollutants
on Young Salmon and Trout.” Research Bulletin No. 5,
State of Washington, Department of Fisheries, 1960.
9. Robert A. Taft Sanitary Engineering Center, “Interaction of
Heavy Metals and Biological Sewage Treatment Processes.”
PHS Publication No. 999-WP-22, 1965, p. 6.
10. McKinney, R. E., Tomlinson, H. D. • Wilcox, R. L. ,
Industrial Waste . 28, 1956, pp. 547-557.
-------
DEFINITION OF TERMS
jgae -— Simple plants, many microscopic, containing
chlorophyll.
Biota —- All the living organisms of a region.
BUD -- Biochemical Oxygen Demand. A measure of the amount
of oxygen required for the biological decomposition of dissolved
organic solids to occur under aerobic conditions and at a
standardized time and temperature.
COD -- Chemical Oxygen Demand. A measure in terms of the
amount of oxygen required to chemically oxidize all organic
compounds, with a few exceptions, and some reduced inorganic
compounds.
Cold Deck -- A method of log storage where logs are stacked
in piles and kept wet to prevent checking by use of sprinklers
located on top of the stack.
Conductivity -- Referred to as specific conductance at a
specified temperature (25°C). The opposite of resistance and
used as a measure of the concentration of total ionized solids
in water. Reported in micromohos (uMHOS).
Dissolved Solids —— Solids which are in solution.
Exterior Grade Plywood -- Plywood made with 100 percent
waterproof glue and a high grade veneer.
Fauna -— The entire animal life of a region.
-------
82
Flora -- The entire plant life of a region.
.2!1I. -— Gallons per minute.
Green End -- Portion of a plywood plant involving the
storage and handling of logs through the process of turning
them into veneer.
Interior Grade Plywood -- Plywood made with a moisture
resistant (but not waterproof) glue.
pg/i —- Micrograms per liter (1000 ig/l = 1 mg/i).
mg/i Milligrams per liter (100 mg/i 1 gm/i).
-— Million gallons per day.
MLSS -- Mixed liquor suspended solids.
-- The negative log of the hydrogen ion concentration.
The pH scale is usually represented as ranging from 0 to 14,
with a pH of 7 representing neutrality. Acid conditions increase
as pH values decrease, and alkaline conditions increase as pH
values increase.
Phenols -- (C 6 H 5 OH). The monohydroxy derivative of benzene,
known as carbolic acid. Phenols are waste products of oil
refineries, coke plants, and some chemical producing facilities.
Phenols are used extensively in the synthesis of phenolic type
resins. Concentration of phenols in the order of .01 to .1 mg/i
are detectable by taste and odor tests.
ytoplankton -- Plant Microorganisms, such as certain
algae, living unattached in the water.
-------
83
Plankton -- Aquatic plant and animal organisms of small
size, mostly microscopic, that have relatively small powers of
locomotion or drift in the water subject to wave action and
currents.
Sphaerotilus sp. -- Slime-forming bacteria.
Spreader Shift -- One spreader running one shift (8 hours).
Supernatant -- The liquid overlaying the solids which have
settled.
Suspended Solids -- Solids that float on the surface or
are in suspension in water, sewage, or other liquids.
TL -- Medium tolerance limit. The concentrations of
material which 50 percent of the test animals can survive for
the length of the test period.
TOC —- Total Organic Carbon. Reported as carbon (C).
Total Kjeldahl Nitrogen -- Organic nitrogen and nitrogen
in the form of ammonia (NH 3 ). Does not include nitrogen in the
form of nitrates (NH ) and nitrites (NO ).
Total Phosphate -- Phosphorus in organic and inorganic
forms. Phosphorus and nitrogen are nutrients necessary for
maintaining biological growth.
Total Solids -- The sum of the suspended and dissolved
solids.
Total Volatile Solids -- The quantity of solids in water,
sewage, or other liquids lost on ignition of the total solids
at 600°C (1112°F).
-------
84
Total Volatile Sus p ended Solids The quantity of solids
in water, sewage, or other liquids lost on ignition of the
suspended matter at 600°C (1112°F).
Veneer -- A thin sheet of wood turned off a log by a
lathe and used in the production of plywood.
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