DEPARTMENT OF THE INTERIOR

UNITED STATES GEOLOGICAL SURVEY

GEORGE OTIS SMITH. DIBECTOB

WATER-SUPPLY PAPER 226

THE POLLUTION OF STREAMS BY 

SULPHITE PULP WASTE

A STUDY OF POSSIBLE REMEDIES

BY

EAKLE BERNARD PHELPS

Investigation made at the Sanitary Research Laboratory and Sewage Experiment Station 

of the Massachusetts Institute of Technology

WASHINGTON

GOVERNMENT FEINTING OFFICE 

1909

Library Copy
DEPARTMENT OF THE INTERIOR

UNITED STATES GEOLOGICAL SURVEY

GEORGE OTIS SMITH, DIRECTOR

WATER-SUPPLY PAPER 226

THE POLLUTION OF STREAMS BY 

SULPHITE PULP WASTE

A STUDY OF POSSIBLE REMEDIES

BY

EARLE BERNARD PHELPS

Investigation made at the Sanitary Research Laboratory'and Sewage Experiment Station 

of the Massachusetts Institute of Technology

WASHINGTON

GOVERNMENT PRINTING OFFICE 

1909
CONTENTS.

Introduction............................................................ 5

Stream pollution by sulphite pulp waste liquor............................. 6

General discussion.................................................... 6

Pollution of Lake Champlain......................................... 6

Pollution of James River.............................................. 6

Pollution of Potomac River.......................................... 8

Pollution of Black River............................................. 8

Manufacture of sulphite pulp .............................................. 8

The wood............................................................ 9

The acid liquor....................................................... 9

The digester......................................................... 10

The "cook".......................................................... 11

Screening and washing the stock....................................... 12

Bleaching the stock................................................... 13

Summary............................................................ 15

Sulphite pulp waste liquor................................................ 15

Previous investigations............................................... 15

Amount of waste per ton of pulp ...................................... 18

Chemical composition of the waste liquor............................... 20

Chemical nature of the organic material.................... ^........... 21

Purification of sulphite waste liquor ................................... 22

Utilization of sulphite waste liquor ................................... 24

Experimental investigations with the organic material...................... 27

Preparation of crude "lignone " ....................................... 28

Solubility of crude "lignone " ....................................... 28

Reactions with phosphorus chlorides .................................. 28

Fusion with alkali................................................... 29

Position of the sulphur in '' lignone " .................................. 29

Reactions with aromatic amines ....................................... 30

Reactions of the amine-condensation products with nitrous acid.......... 31

Reactions with nitric acid ............................................ 31

Lignone yellow....................................................... 32

Reactions of the amine-condensation products with nitric acid .......... 33

Sulphur dyes......................................................... 34

Commercial possibilities of lignone dyes ................................ 35

Conclusion.............................................................. 35

Survey publications on stream pollution................................... 37

ILLUSTRATION.

PLATE I. Diagram illustrating the steps in the manufacture of wood pulp by

the sulphite process ........................................... 16

3
THE POLLUTION OF STREAMS BY SULPHITE PULP 

WASTE-A STUDY OF POSSIBLE REMEDIES:

By EARLE BERNARD PHELPS.

INTRODUCTION.

The pollution of streams by the waste liquors resulting from the 

manufacture of paper pulp by the sulphite process constitutes one of 

the most serious stream-pollution problems with which science has 

to deal at the present time. The seriousness of the problem is the 

direct result of two factors the tremendous volume of such waste 

liquors and their high content of organic matter of extremely undesirable character. An approximate estimate of the amount of 

sulphite waste liquor discharged into the streams of the United 

States in one year is given in the subjoined statement, compiled from 

data in Forest Circular No. 120, Forest Service, United States 

Department of Agriculture.

Amount of sulphite waste liquor discharged into streams of the United States during 1906.

Million gallons.

Maine...................................................... 560

Massachusetts............................................... 45

Michigan.................................................... 175

New Hampshire ................. ........................... 380

New York ........ .......................................... 1,000

Ohio......................................................... 41

Oregon .......................... ........................... 52

Pennsylvania........... ..................................... 217

Virginia..................................................... 84

West Virginia................................................ 89

Wisconsin..... ..... ....................................... 540

All other States .............................................. 44

3,227

According to the above estimate, the total amount of this liquor 

discharged into streams throughout the country in one year is more 

than three billion gallons, and when it is considered that of this 

enormous amount 10 per cent by weight, or more than 2.5 billion 

pounds, is solid matter, mostly organic, it will be readily conceded 

that the problem of its disposal is one of no small magnitude.

a This investigation was made iti cooperation with the sanitary research laboratory and sewage experiment station of the Massachusetts Institute of Technology.

5
6 POLLUTION OF STREAMS BY SULPHITE PULP WASTE.

STREAM POLLUTION BY SULPHITE PULP WASTE LIQUOR.

GENERAL DISCUSSION.

Though the pollution of streams by sulphite pulp waste is an 

obvious and serious matter in the region where sulphite mills exist, 

the literature contains but few references which throw any light on 

the actual damage caused. In Germany the regulations of the sanitary authorities are strict. Ahrens a states that pulp manufacturers, 

in spite of constant endeavor, may come into conflict with the 

authorities because they are not able to meet the requirements in 

regard to the discharge of waste waters into rivers, and he adds that 

many factories in Germany have actually been obliged to shut down 

for that reason. Sanitary officers in the United States are more 

lenient. This is due partly to the fact that the streams in this 

country are larger and the greater number of the sulphite mills are 

located in less densely populated regions.

POLLUTION. OF LAKE CHAMPLAIN.

In some places stream pollution from this cause has been so serious 

as to warrant investigation. Leightoii,6 in his investigation of the 

pollution of Lake Champlain, made a study of sulphite pulp waste as 

it affects Ausable River, which he found ^o be a black, foul, grossly 

polluted stream in which the existence of fish or other forms of life is 

impossible. He concluded, however,. that the great dilution of the 

river waters by those of the lake renders the pollution insignificant 

so far as the lake waters are concerned.

POLLUTION OF JAMES RIVER.

Levyc made a careful study of the effect of sulphite waste pollution on James River. The sources of pollution are at Covington, Va., 

about 250 miles by water above Richmond, whose public supply is 

derived from this stream. Levy found Jackson River, into which 

this liquor is discharged and which unites with the Cowpasture below 

Iron Gate to form the James, to be perfectly clear and colorless. 

The waste entering the stream first turns the water dark brown and 

later a purplish black. Foam is created at the outfall and wherever 

the stream is interrupted by falls or by rapids. This appearance can 

be noted for the entire distance from Covington to Richmond. 

Dilution is practically the only means of improvement. On the 

sanitary side of the question Levy considers two problems (1) whether

o Zeitschr. angew. Chemie, 1895, p. 41.

& Leighton, M. O., Preliminary report on the pollution of Lake Champlain: Water-Supply Paper U. S. 

Geol. Survey No. 121, 1905.

cLevy, E. C., Report to the water committee on the investigation of the effect of trades wastes on the 

water of James River at Richmond. Richmond, 1905.
EFFECT ON VAEIOUS STEEAMS.

the substances introduced are themselves actually injurious to health, 

and (2) what influences they may have on the multiplication of 

bacteria. The liquor itself as it enters the river is absolutely sterile, 

not only on account of the actual germicidal substances which it 

contains, but also on account of the fact that it has been subjected 

for about twelve hours to steam under a pressure of 80 pounds to the 

square inch. Its germicidal properties are shown in the following 

table:

Germicidal action of sulphite waste liquor on bacteria in highly polluted water from

Shockoe Creek.

[By E. C. Levy.]

Per cent, by volume, of liquor in mixture.

1....... ............ ..............................

5....................... ............................

10............. ... ..... ............................

25....................................................

Number of bacteria per cubic 

centimeter.

At start.

450, 000

427. 500 

405, 000 

337, 500

After 6 

hours.

900,000

60,000 

35, 000 

10

After 24 

hours.

2, 500, 000 

a 7, 500, 000 

170, 000 

0 

0

Per cent of reduction ( ) 

or increase 

(+) 

In 6 

hours.

+100

- 86 

- 91.4 -100

In 24 

hours.

+ 455 

+1,585 

- 60.2 

- 100 

- 100

« I'late liquefied.

The number of bacteria in the water at the commencement of the 

experiment is calculated from the number of bacteria present in the 

creek water itself (450,000). Where the reduction is more than 99.95 

per cent it is given as 100 per cent. Even very small amounts of 

the waste liquor have an antiseptic action, but are not actually germicidal; they restrain the growth of bacteria without killing them. 

Such action may be harmful rather than otherwise, for- in a stream 

receiving sewage certain kinds of bacteria eventually render the sewage harmless. It would seem that as the character of this waste is 

so stable it does not furnish food for bacterial growth.

Complaint is made that the water of the James at Richmond is 

unfit for boiler use, both on account of its corrosive action and on 

account of the "priming" due to vegetable matter present. Aside 

from the matter of actual harm, however, Levy states that the water 

is rendered objectionable in appearance by this waste. The darkbrown, almost black water", with its accumulation of dirty scum, is 

not relished by the consumer, even if he knows that it is probably 

safe to drink it. In a bath tub this color is very pronounced, and 

even in so small a quantity as a tumblerful it is decidedly noticeable. James River is practically clear for certain periods of each 

year, and at such periods, under normal conditions, no further treatment than mere storage would be required for furnishing satisfactory 

water. But during these periods, on account of the low stage of the
8 POLLUTION OF STEEAMS BY SULPHITE PULP WASTE.

river, the trouble from Covington is most marked. Plain sedimentation has absolutely no effect on the color; but coagulation will 

remove a large part of it, and Levy found not less than 3 grains of 

alum per gallon necessary for this purpose. He estimates that with 

a daily consumption of 14,000,000 gallons it would cost $75 a day 

for alum, which would not be required if it were not for the sulphite 

pollution, and states that even then the water would not be perfectly 

satisfactory.

Farther up the river complaints have been made that fish havebeen killed by the sulphite waste. The opinion is expressed that if 

fish are killed it is perhaps because the free oxygen, which is necessary 

for their life, is used up, rather than because of the presence of substances actually poisonous in themselves.

POLLUTION OF POTOMAC RIVER.

Some experiments to determine the effect of sulphite waste pollution on fish life in Potomac River are reported by Marsh.0 He found 

a decidedly injurious effect on fish of different kinds in dilutions varying in strength from 1 part of waste liquor in 50 parts of water to 

1 part in 200 parts of water.

POLLUTION OF BLACK RIVER.

Whipple 6 has referred to the effect of sulphite pollution on the 

water supply of Watertown. He states that the sulphite liquors contribute to the odor and color of the water, and necessitate the use of 

greater amounts of alum than would otherwise be necessary.

MANUFACTURE OF SULPHITE PULP.

In order that the character and amount of the waste liquors resulting from the manufacture of wood pulp by the sulphite process may 

be comprehended it will be necessary to describe, in some detail, the 

various operations that are conducted in a sulphite mill to convert 

spruce logs into paper pulp. The processes in use at the Mechanicsville mill of the West Virginia Pulp and Paj>er Company will be 

described, as they are typical of a modern sulphite mill of average 

capacity. Though there are naturally many variations in minor 

details, the essential steps are similar at all mills, so that a detailed 

description of the processes of one mill, with an occasional statement 

of important alternative methods, will serve the purpose of this 

discussion.

a Marsh, M. C., in Parker, H. N., and others, The Potomac River basin: Water-Supply Paper U. S. 

Geol. Survey No. 192, 1907. 

6 Whipple, G. C., Proc. Watertown Soc. Eng., Watertown, N. Y., 1906.
MANUFACTURE OF SULPHITE PULP. 9 

THE WOOD.

Spruce and hemlock are the woods used almost exclusively for the 

manufacture of pulp by the sulphite process. The logs are either 

barked by hand in the woods before seasoning or by machinery at 

the mill. Machine barking necessitates cutting the log into 2-foot 

lengths; in hand work 4-foot lengths are used without further cutting. 

Machine barking also causes some waste of material through cutting 

too deeply into the log. Some measurements of logs barked by machinery show that the original circular section of the log had been 

changed to that of a circle minus 6 small segments, the area of the 

segments being found to be 18 per cent of that of the original circle. 

All logs are carefully inspected at the mill, and those in which there is 

evidence of decayed portions or unremoved bark are rejected. Subsequently a man removes the bark and decayed places from these imperfect logs with an ax. The logs are thrown into a large tank of hot 

water to loosen the ice, dirt, and sand which have adhered to them. 

They then pass through scrubbers, in which a powerful spray of water 

removes all the sand and cinders. They are then ready for the chipper. 

This machine consists essentially of three knife blades in a rapidly 

revolving vertical steel disk. One end of the log is pressed against 

these blades at an angle, and in a few seconds the log is reduced to 

chips. The resulting fragments are then run over screens to separate 

them into three portions. Everything that passes through a f-inch 

mesh is discarded. This chip dust is at present practically a waste 

product, though it is used to some extent for packing ice and for bedding horses. A half-day test at the Mechanicsville mill showed that 

1,375 pounds of chip dust, or about 2.7 per cent of waste, resulted 

from chipping 17 cords of wood. The chips which do not pass 

through a 1-inch mesh are next separated and passed through a machine known as a shredder. This machine, working on a novel principle, crushes the large chips into shreds and separates the good wood 

from the knots to a large extent. The shredded mixture is then 

'' floated'' over a long water tank, in which the knots, by virtue of their 

greater specific gravity, sink to the bottom. The separation here is 

almost complete, and the removal of the knots at this time is of great 

benefit, as they interfere seriously with subsequent operations. The 

middle portion of the chipped mixture, which is retained on a |-inch 

screen and passes through a 1-inch screen, goes directly by belt conveyors to the storage bins over the digesters, as does also the floated 

portion of the shredded chips after a second screening. The chips 

are now ready for the digester.

THE ACID LIQUOR.

The solution of chemical reagents used in the digester to dissolve 

out of the wood all intercellular and other noncellulose matter consists essentially of calcium and magnesium bisulphites with an excess 

of free sulphurous acid. It is made by passing sulphur dioxide 

60596 09 2
10 POLLUTION OF STREAMS BY SULPHITE PULP WASTE.

through a suspension of milk of lime made from dolomitic lime, or 

through towers of limestone over which water is trickling. The 

former process is in most general use in this country. A suspension 

of slaked lime (milk of lime) is made, having a strength of about 

1.2° B. that is, about 1.3 per cent Ca(OH) 2 . Gaseous sulphur dioxide 

is prepared either by roasting pyrite or by burning sulphur directly in 

specially designed burners. The gases are passed through lead pipes 

submerged in large tanks, through which cold water is running, as it 

is essential to keep the absorption .apparatus as cool as possible. The 

cooled gas next goes into a tank of milk of lime, which is nearly saturated by allowing the gas to enter at the bottom and to bubble up 

through the liquid. The unabsorbed gas is conducted from the top 

of this tank to the bottom of a second tank filled with fresh milk of 

lime, where the absorption is completed. The residual gases then 

pass to the pumps, which maintain a partial vacuum in'the tanks and 

insure a constant flow of gas. During absorption the contents of the 

tank are constantly stirred. .When the acid liquor in the first tank is 

of the requisite strength, as shown by analysis, it is pumped into the 

acid storage tanks, the second tank is emptied into the first, and fresh 

lime is added to the second. The process of absorption is then repeated. The composition of the acid liquor varies in different mills 

and even in the same mill from time to time as the quality of wood 

varies. A specimen analysis of the liquor, expressed in the mill 

terms, showed free sulphur dioxide, 2.5 per cent; combined sulphur 

dioxide, 1.1 per cent; a total of 3.6 percent. "Free sulphur dioxide" 

is the total acidity of the solution expressed as SO2 . It is therefore 

the free dissolved gas plus one-half the sulphur dioxide present as 

bisulphite. The "combined sulphur dioxide" represents the rest of 

the bisulphite radicle. The actual composition of the liquor is therefore as follows, the total base being regarded as calcium:

Analysis of sulphite liquor.

Per cent. 

Calcium (Ca)..................................................... 0. 7

Sulphur (S)........................................................ 1.8

or, in combination 

Calcium bisulphite (CaH2(SO3) 2).................. ............... 3. 5

Dissolved sulphur dioxide gas (SO.,).. ............................. 1.4

For one charge of a digester of average dimensions, 12.8 by 34 feet, 

producing about 7 tons of dry pulp at each "cook/' 16,000 gallons of 

acid liquor are used.

THE DIGESTER.

The digester consists of an upright steel cylindrical shell with a 

conical bottom and a nearly hemispherical top, lined with lead, 

within which is another lining of resistant glazed brick, pointed with a 

special mortar. Older forms of digesters have concrete linings. The 

inside dimensions of a digester of average size are, diameter 12.8 feet, 

total height 34 feet, and its capacity is about 2,700 cubic feet.
MANUFACTURE OF SULPHITE PULP. 11 

THE "COOK."

About 12 cords of wood chips are first placed in the digester, and 

then about 16,000 gallons of the acid liquor are run in, filling the 

digester within 6 feet of the top. The shell is then closed tightly and 

steam is admitted. The contents are brought rapidly to boiling temperature and then the pressure is raised gradually to about 65 pounds, 

two hours being consumed in this heating. During the next two hours 

the pressure is increased more slowly to about 80 pounds. At this 

point the digester is full of liquor, the water condensed from incoming 

steam having completely filled the space which was left at the time of 

filling. In order, therefore, to add more steam it is necessary to 

"relieve." This process consists in allowing the liquor slowly to 

escape from the top of the digester as steam enters at the bottom. 

This relief liquor is strongly acid, and as a rule is returned to the acidliquor tanks to be used again. There is some objection to such 

recovery of the relief, because it is rather dark colored and is apt 

slightly to color the next "cook." The temperature is carefully noted 

and frequent analyses of the liquor within the digester are made 

during the "cook," especially during the last two hours. Small 

samples for analysis are drawn from a tap in the side of the digester 

near the top. They are examined for total sulphur dioxide and the 

color and odor are noted. If in the opinion of the attendant the 

reaction is proceeding too fast, the incoming steam and the relief 

are both shut off and the "cook" is "held." It is intended to complete the "cook" in about six hours. Nearly at that time the sulphur 

dioxide content begins suddenly to fall, the color becomes darker, and 

a peculiar characteristic odor develops. The reactions at that time 

are proceeding very rapidly and the charge must be blown immediately 

or a dark-colored stock will result. The skill of the operator is here 

well shown in bringing about this rather sharp end point at almost 

the exact time desired, six hours. A large blow-off valve is then 

opened at the bottom of the digester and its entire contents are blown 

under full pressure into the blow pit, wrhich is a large covered wooden 

tank, 22 feet in diameter and 20 feet deep, provided with a large air 

shaft for the escape of the steam and gases. Opposite the end of the 

pipe leading from the digester there is a bronze baffle plate, against 

which the contents of the digester are thrown with great force. The 

pit is provided with a false bottom and the liquor is rapidly drained 

off. It is essential at this point to remove all the acid liquor as 

rapidly as possible. After the blowing the liquor darkens rapidly 

from a light-garnet shade to nearly black, and its retention in the pulp 

results in a dark-colored product. About 15,000 gallons of wash 

water are added as soon as possible and drained off. A second 

washing is then given with the same amount of water, when the
12 POLLUTION OF STREAMS BY SULPHITE PULP WASTE.

drains are closed, more water is added, and the stock is ready to be 

pumped to storage tanks, A small amount of the acid liquor is taken 

out during the "cook" as relief, but the principal part of it is discharged at the end of the "cook," constituting the sulphite pulp 

waste liquor.

SCREENING AND WASHING THE STOCK.

The two processes of screening and washing the stock are carried on 

simultaneously, and can best be described together. The stock is 

pumped from the blow pit into storage tanks, from which it is pumped 

as fast as needed into an elevated tank, flowing thence to the screens 

and the washing machinery. It first passes through a long revolving 

cylindrical screen, slightly inclined from the horizontal and provided 

on the inside with a continuous worm-shaped vane. This screen is 

very finely meshed, and its function is to remove a large part of the 

water from the stock. Next the stock passes into a similar cylinder 

with rectangular meshes about one-fourth of an inch wide and 1 inch 

long. The wood fiber is washed through these meshes by the aid of a 

stream of water playing from above. AH knots and undigested chips 

are retained* in this screen, collected at its open end, and measured, 

the amount and character of the undigested portions being regarded 

as a valuable criterion of the care with which the preceding processes 

have been conducted. On the average, there will be about 4 cubic 

feet of this material per "cook," or a little over half a foot per ton of 

dry pulp. The stock passes from these screens to the settling tanks 

or "rifflers," long troughs about 6 feet wide and 2 feet deep, provided 

with baffles on the bottom for the retention of sediment. The object 

of the tanks is to remove by sedimentation any sand or grit which may 

have gained access to the stock from the machinery or otherwise. 

The stock is now ready for the final screening, by which it is separated 

into marketable stock and tailings. The tailings from the first 

screening process are generally run through a second screen and a 

little good fiber is saved in that way. The final tailings are passed 

over a wet machine and felted into low-grade pulp, which is sold 

for use in the manufacture of leather board. The screened pulp also 

is passed over a wet machine, which is essential!}7 a revolving screen 

that separates the bulk of the water from the pulp, leaving the latter 

in a rather thick sheet. If the pulp is to be sold or used as unbleached 

pulp, it is taken from the wet machine at this point, passed between 

large wooden rollers, and finally removed in the form of thick sheets 

of wet pulp. If it is to be bleached, it is removed mechanically from 

the rolls of the wet machine, mixed with a large volume of water, and 

conducted to the bleach tanks.
MANUFACTURE OF SULPHITE PULP. 13 

BLEACHING THE STOCK.

The unbleached pulp as it comes from the wet machine has a very 

slight brownish color, although it appears pure white to the inexperienced eye. If such pulp is made into paper, however, it is likely to 

darken rapidly with age and drying, so that pulp for high-grade 

papers must be bleached with chloride of lime. Commercial chloride 

of lime, or bleaching powder, consists mainly of calcium hypochlorite, 

and it is made by passing free chlorine gas over quicklime. The 

trade name, chloride of lime, is therefore a misnomer. A typical 

analysis, by Wagner, a of bleaching powder of good quality is given 

herewith:

Analysis of chloride of lime.

Calcium hypochlorite (2CaOCl2 +H2O) .......................... 82. 65

Calcium carbonate (CaC03)................................... .95

Calcium chloride (CaCl2)..................................... .44

Calcium hydrate (Ca(OH)2) ................................... 6. 80"

Water (H20), free....... ...................................... 9. 82

100, 66

Inasmuch as the chlorine alone of the hypochlorite is available for 

bleaching purposes, a sample of bleaching powder having the above 

analysis would contain 43 per cent of '' available'' chlorine and would 

be called a 43 per cent bleach. The product on the market seldom 

contains so much chlorine as that, good grades in this country running 

from 35 to 40 per cent available chlorine.

The bleaching powder, or "bleach," as it is called in the mill, is 

received in large iron casks, each holding about 600 pounds. They 

are emptied into a mixing tank with approximately 3 gallons of water 

to a pound of bleach. Generally, an ordinary tank provided with a 

rotary agitator is used for this mixing, but at the Mechanicsville mill 

an improved mixer is in service, which appears to be very efficient. 

The tank is conical in shape, about 15 feet high and 10 feet in diameter 

at the top, tapering to a point at the bottom. A centrifugal pump 

with a 3-inch discharge is near the tank at its bottom level. This 

pump withdraws the liquid mixture from the bottom of the tank and 

discharges it horizontally into the upper part in a direction tangential 

to the periphery. Circulating the liquor through the tank in this 

manner produces an immense vortex, so that, although the liquor 

whirls about the sides of the tank to the level of the inlet, one can 

look down into this vortex almost to the bottom of the tank. This 

process accomplishes a thorough mixing of bleach and water in a comparatively short time. The mixture then flows into a large brick

a Wagner, R. von, Manual of chemical technology; trails, from 13th German ed. hy Sir William Crookes, 

New York, reprint of 1904, p. 360.
14 POLLUTION OP .STREAMS BY SULPHITE PULP WASTE.

settling tank and is allowed to settle until a clear liquor can be 

decanted. This liquor is tested for strength with a Baume hydrometer and is mixed with the proper amount of a weak bleach extract 

to give it the required strength of about 3° B. This weaker solution 

is made by a second extraction of the sludge or "grout" remaining 

after the first decantation. The grout is usually strengthened by the 

addition of a small amount of fresh bleach, agitated with a fresh 

supply of water, and again submitted to sedimentation. The liquor 

obtained constitutes the weak bleach mentioned above, while the sludge 

remaining, the "second grout," is agitated a third time with fresh water 

and again settled. The third lot of supernatant liquor constitutes the 

water used in the first extraction of a new lot of bleach; the "third 

grout" is a waste product. Reference to the analysis already given 

will show that it consists essentially of calcium hydrate, with more or 

less carbonate of calcium and other impurities derived from the 

original lime from which the bleaching powder was prepared.

The bleach solution of about 3° B. is mixed with pulp in the proportion of about 30 gallons of solution to 100 pounds of pulp.a The 

mixture is passed successively through a series of tanks, eight in 

number, in which it is brought to and maintained at a temperature of 

about 100° F. and is mechanically stirred. Tests of this mixture are 

constantly being made as it passes from each tank to the next, and 

additional bleach solution is added as required, the processes being so 

regulated that, after the complete treatment, requiring about six hours' 

time, the pulp will be satisfactorily bleached and the bleach will be 

exhausted as completely as possible. It is next necessary to wash out 

of the pulp mixture the residual bleach and the calcium chloride 

resulting from the process. This is accomplished by first passing the 

stock under a series of washers. A washer is essentially a frame, in 

the form of an eight-sided prism, covered with fine-meshed copper 

gauze, and mounted on a horizontal axis, so that it is about half submerged in the pulp. It rotates slowly in the direction of the moving 

stream of stock, and as the water passes through the gauze it is collected in buckets suitably arranged within, elevated to a position 

above the center line of the box, and discharged through a side outlet. 

By this means a considerable volume of water is separated from the 

stock. Fresh water is admitted after each treatment and the washing 

is repeated several times, after which the washed stock is passed over 

a wet machine as previously described. It is then either pressed into 

sheets of wet pulp or, if it is to be used at once in the mill, is removed 

from the rolls by a stream of fresh water and run directly to the paper 

mill.

a All references to pulp in these processes are to the actual weight of air-dry pulp in the mixture, though 

the pulp is always mixed with a considerable amount of water throughout the process of manufacture.
SULPHITE PULP WASTE LIQUOK. * 15 

SUMMARY.

The various processes described in the foregoing pages have been 

arranged for convenient reference in diagrammatic form in Plate I. 

The raw materials that enter into the process are shown along the 

top line of the diagram in capitals. They are wood, lime, sulphur 

(or pyrite), bleaching powder, and water. Arranged vertically at the 

left is a list of the waste and by-products of the process, namely, 

bark, sawdust, knots, sulphite waste liquor, sand and grit, and sludge 

or grout from "the bleach-solution tanks. Much of the water used in 

the later processes is returned and used for washing the freshly 

cooked pulp, so that practically the only liquid waste is the waste 

acid liquor and the first wash waters, these together making up the 

sulphite waste liquor. At the bottom of the diagram the finished 

products of the process are shown, namely, low-grade unbleached 

pulp and bleached sulphite pulp. Disposal of the grout involves 

no serious difficulties. It is usually discharged into low-lying fields 

or into artificially constructed basins, where it is converted into compact masses of carbonate of lime. The small amount of chip dust is 

readily used in ice houses or as a bedding material for horses. The 

bark if removed at the mill is either burned or given away for fuel, 

though it is generally more economical to have the barking done 

before shipment. In the study of stream pollution, therefore, consideration need be given only to the combined waters resulting from 

the digestion of the chips and the subsequent washings of the pulp 

that is, the liquor here called the sulphite pulp waste liquor.

SULPHITE PULP WASTE LIQUOR.

PREVIOUS INVESTIGATIONS.

This waste, arising as it does from an industry involving elaborate 

chemical methods and necessarily employing skilled paper-mill 

chemists, has probably received more careful and systematic study 

than any other waste product of the present day. A prize of 10,000 

marks was offered in Germany in 1894 for the best method of preventing the pollution of streams by sulphite liquor, but it still remains 

unawarded. Scores of processes for utilizing or purifying the waste 

have been patented in Germany, England, and the United States, 

but none of them has been sufficiently successful to relieve, in any 

noticeable degree, the burdensome situation. Technical literature 

contains reports of exhaustive researches on the constitution of the 

organic substances found in this liquor, but there is no satisfactory 

agreement on this point. No more striking commentary on the difficulty of the problem can be made than the bare statement that, in 

spite of all these researches, the substance is still classed as a waste
16 POLLUTION OF STREAMS BY SULPHITE PULP WASTE.

product. According to Cross and Bevan, a who summarize a paper 

by H. Seidel, 6 no satisfactory application of this by-product has yet 

been evolved. Evaporation and combustion involve losses of sulphur.c A more complete regeneration of the sulphur has been the 

subject of a series of patents.d The process of V. B. Drewson6 consists in heating with lime under pressure, yielding calcium monosulphite. The sulphite is redissolved as bisulphite by treatment with 

sulphurous acid. This process is relatively costly, and yields necessarily an impure lye. It has been proposed to employ the product 

as a foodstuff both in its original form and in the form of benzoate/ 

but its unsuitability is obvious from its composition. A method of 

destructive distillation has been patented. Seidel/ however, found 

on investigating the process that the yield of useful products is much 

too low for its economical development. Fusion with alkaline 

hydrates for the production of oxalic acid A is also excluded by the 

low yield of the product. The application of the liquor to tanning 

purposes* appears promising from the fact that 28 per cent of the 

dry residue is removed by digestion with hide powder, but this application has been investigated without practical success. Various 

probable uses are suggested by the viscosity of the evaporated extract, 

but as a substitute for glue it has proved of little value. It is also 

used to some extent as a binding material in the manufacture of 

briquets and as a substitute for gelatine in the petroleum industry. 

Cross and Bevan^ and Mitscherlich* precipitate a compound of the 

lignone complex and gelatine by adding a solution of the latter substance to the sulphite waste liquors. The compound is redissolved 

in weak alkaline solutions and employed in this form for engine-sizing 

papers. Ekman has patented a processl for "salting out" the lignone 

sulphonates, the product being resoluble in water and the solution 

having some of the properties of a solution of dextrin. Owing to its 

active chemical properties this product, "dextron," has a limited 

capability of being substituted for dextrin. The suggestion to 

employ the evaporated extract as a reducing agent in indigo dyeing 

and printing has also proved unfruitful. Seidel's application of the 

soda salt of the lignone sulphonic acid as a reducing agent in chromea Researches on cellulose, 1895-1900, p. 150.

&Zeitschr. angew. Chemie, 1900.

e German patents Nos. 74030 and 83438; also Seidel and Hanak, Mitt. Techn. Gew. Mus., 1808.

a. German patents Nos. 40308/69892, 71942, 78306, and 81338.

« German patent No. 67889.

; German patent No. 97935.

a German patent No. 45951.

A German patent No. 52491.

* German patent No. 72161.

; British patent No. 1548, 1883.

k German patents Nos. 93944 and 93945.

i German patent No. 81643.
U. S. GEOLOGICAL SUKVE

WOOD, barked, scrubbed, chipped, screened LIME, WATER SULPH

Bark

Chip dust

Large chips, shredded, floated Small chips

I ; Milk of lime Sulphu

Knots

Chips

Waste liquor

Wash water

Screen water

Sludge, Ca(OH),, CaCO,,etc.

To hoppers

Acid liquor

To tanks

 I ; 

Digester charge, cooked for six hours, blown 

I 

Stock, washed and drained 

Stock, washed in screen

Stock, screened for kn

Undigested knots Stock, passed thro

Sand and grit Stock, screene

Stock Tailing

Tailin

Unbleached pulp Water, returned for 

To bleach tan

Bleached pulp, washed Spe

Washed bleached pulp Wash water

To wet machine

I 

Market pulp

Low-g

DIAGRAM ILLUSTRATING THE STEPS IN THE MANUFACTURE OF WOOD PULP 
SULPHITE PULP WASTE LIQUOE. 17

mordanting wool and woolen goods a is more successful in practice, 

and its industrial development shows satisfactory progress. The 

product is known as "lignorosin." In another place, however, 

Cross and Bevan 6 comment on this process by calling attention to the 

fact that such use for a by-product, produced in such enormous 

quantities, is of relatively small importance.

It is remarkable that the main by-product of the bisulphite process 

is still for the most part an absolute waste, notwithstanding the many 

investigations of technologists and attempts to convert it to industrial use. As it represents a percentage of the wood pulped equal to 

that of the cellulose obtained, it is a waste of potentially valuable 

material that must be termed colossal. Moreover, as a waste to be 

discharged into watercourses, it becomes a source of burden and 

expense to the manufacturer, and with the increasing restrictions on 

the pollution of rivers it constitutes in many localities a problem to 

be solved only by the cessation of the industry. The alternative in 

such cases is dealing with it destructively that is, by evaporating 

and burning it. In this treatment the high calorific value of the 

organic matter appears on the credit side; but, as calcium and magnesium bisulphites are used, the residue from calcination is practically 

without value. If, however, a soda base is substituted, the alkali is 

recoverable in such form as to be directly available for the alkalinesulphide or Dahl process. As a more complicated alternative the 

soda can be recovered by the old black-ash or Leblanc process, and 

the sulphur by the now well-established Chance process, in which 

lime must be added to the concentrated liquors before calcination. 

The engineering features of the system in respect to evaporating and 

calcining are the same. Economic working requires (a) evaporation 

by multiple effect and (6) calcining on the continuous rotary principle. For the latter process the draft of air is concurrent, by a special 

device, with the movement of the charge in the furnace, a feature by 

which a progressively increasing temperature within the furnace is 

procured. This interesting development has been elaborated by 

Drewson and Dorenfeldt, to whose publications readers who wish to 

inform themselves in detail in regard to these developments are 

referred. The present necessity of a destructive treatment of the 

sulphite waste liquor being assumed, their scheme has many advantages ; sodium bisulphite liquors are more economically prepared and 

the pulp obtained is superior in paper-making quality and in economy 

of bleaching to that resulting from the calcium or magnesium bisulphite processes. The soda may be recovered in a form in which it 

is immediately available as a powerful hydrolyzing alkali in the

« German patent No. 99682.

6 A text-book of paper making, 2d ed., 1900, p. 143.

60596 09 3
18 POLLUTION OF STREAMS BY SULPHITE PULP WASTE.

manufacture of soda pulp, so that these two systems become complementary to one another. The employment of soda as the base also 

affords a new motive for developing the electrolytic processes of 

decomposing salt.

Cross and Bevan's comments present an excellent summary of conditions at the close of 1900. Significant of more recent developments 

in the methods of utilizing or disposing of this waste is the fact that 

in their second volume of " Researches/ ' a a treatise purporting to 

review all work of importance on cellulose industries during the years 

1900-1905, these authors make no mention whatever of the sulphite 

waste problem.

AMOUNT OF WASTE PER TON OF PULP.

It is now practicable to inquire more carefully into the amount of 

the waste and its general characteristics. The important facts to 

be considered in any discussion of stream pollution are the amount 

and the character of the polluting material independent of the 

amount of water in which it may be carried. Chemical analyses of 

the waste liquor in connection with accurate determinations of its 

volume would furnish the requisite information, and such procedure 

is usually adopted. In the present case, however, it happens that 

the amount of polluting material bears a definite relation to the total 

product of the mill in pulp, independent of slight modifications of the 

process, whereas the amount of diluting water varies greatly in different mills and even from time to time in the same mill. For example, 

some mills use the old-fashioned rotary digesters, in which it is not 

necessary to use more than half the amount of water in the acid liquor 

that is used in upright digesters. The washing process is often conducted at places where water is plentiful, with a total disregard of 

economy in water, while in other mills strict economy of water is 

necessary; therefore the concentration of the waste liquors may be 

three or four times as great in one case as in another. In view of 

these facts and of the statement made above, that a definite amount 

of polluting material is produced for each ton of pulp turned out, it 

appears that the best procedure is to determine the definite relationship between the amounts of pulp and solid waste. Results obtained 

at one mill are applicable to any mill using a similar process, though 

the actual volumes of the wastes may be greatly different. After 

having determined this fundamental relation, it is of interest to compare the figures obtained with actual analyses of the waste liquor. 

Such comparison will give an approximate measure of the volume of 

diluting water.

a Researches on cellulose, 1900-1905.
SULPHITE PULP WASTE LIQUOR. 19

A cord of spruce wood ordinarily handled at the mill will weigh 

about 3,600 pounds, of which about 55 per cent, or 2,600 pounds, is 

actual wood substance, the remaining 45 per cent being water. The 

amounts of chip dust, knots, etc., which are really insignificant as 

compared with the total weights, may be neglected in this calculation. About 1,100 pounds of so-called " air-dry" pulp having 10 per 

cent water, or, roughly, 1,000 pounds of actually dry pulp, is made 

from 1 cord of wood. Therefore the production of 1 ton of pulp 

is accompanied by the production of an equal amount of waste 

organic material that is discharged in the waste liquor. According 

to the analysis on page 10, the sulphite liquor contains 0.7 per cent 

of calcium and 1.8 per cent of sulphur, equivalent, respectively, to 

0.058 pound and 0.150 pound per United States gallon. On the basis 

of 16,000 gallons of acid liquor to a digester charge, which produces 

7 tons of air-dry pulp, each ton of pulp is represented by 132 pounds 

of calcium and 343 pounds of sulphur. About 0.1 per cent of sulphur 

dioxide, or 9 pounds of sulphur per ton of pulp, is left unoxidized at 

the end of the "cook." Of the remaining 336 pounds of sulphur 10 

per cent may be allowed for loss of free sulphur dioxide in the relief, 

leaving approximately 300 pounds of sulphur which has been oxidized in the process. The first product of this oxidation is probably 

sulphuric acid, according to the following equation, the oxygen being 

derived from the wood during the digestion :

This presents the simplest idea of the digestive action. Sulphurous acid is oxidized to sulphuric acid with a corresponding reduction 

of the wood substance. The fate of the sulphuric acid thus formed 

has not been satisfactorily determined. It is known that in the final 

product there is little free sulphuric acid. The first effect of its formation would be the precipitation of calcium sulphate, probably on 

the wood fibers. As magnesium sulphate is soluble, this is probably 

the reason why dolomitic lime gives such excellent results. If, 

however, all the calcium or magnesium originally used were converted 

to sulphate, there would be needed for that reaction only 100 pounds 

of sulphur, leaving still 200 pounds of sulphur unaccounted for. It 

'will be shown when the chemical nature of the waste is considered 

that, according to prevailing views, the sulphuric acid from this 

amount of sulphur again reacts with a portion of the wood substance 

to form a so-called sulphonic acid. This may be regarded as sulphuric acid in which one of the OH groups has been replaced by an 

organic radical (R) thus:

H-O/ N) R/ N)

Sulphuric acid. Sulphonic acid.
20 POLLUTION OF STKBAMS BY SULPHITE PULP WASTE.

This reaction is not complete and a small amount of sulphuric acid 

is generally left in the liquor. For the present it will not be necessary 

to discuss the relative amounts of these two acids. The waste material resulting from the digestion of sufficient wood to make 1 ton of 

pulp may be summarized as follows:

Materials in the waste liquor per ton of pulp.

Pounds.

Wood material................................................. 2, 000

Calcium sulphate............................................... 449

Sulphur dioxide (omitted from total)........................... 18

Sulphur in sulphuric acid and in organic combination............ 196

Total solid matter.................................... .. 2, 645

CHEMICAL COMPOSITION OF THE WASTE LIQUOR.

As has been stated, the actual strength of the waste liquor is 

entirely a matter of dilution. The 16,000 gallons of acid liquor used 

in the "cook" producing 7 tons of air-dry pulp is usually diluted with 

one to two times its volume of water in the blow pit, and other wash 

waters later mingle with this liquor in the drains. For the purpose 

of study, however, it is advisable to procure samples of the undiluted 

waste liquors directly from the digester, because in any plan for the 

recovery of tin's liquor it will undoubtedly prove advantageous to 

separate the undiluted liquor. For the investigation here reported 

samples of the liquor were collected from the bottom of the digester 

just before blowing. The hot liquor was drawn into a barrel, allowed 

to cool, and then bottled in carboys for future use. The subjoined 

table gives analyses of this liquor and the figures of several analyses 

of similar liquors by other chemists.

Analyses of sulphite pulp waste liquor. 

[Grams per liter.]

Total solids... ............ .

Ash....................... .......

Analysis of ash: 

Calcium (Ca). ........ . .

Magnesium (Mg) ......... ..... .......

Sulphur (S) .............................

Sulphite radicle (SO,) . ......................

Sulphate radicle (SO-f)...-. ............ .

1.

82

13

1.2

9

10.5

1

Dfi

2.

82

68

14

::::::

9 G

7.3

4.1

q

88

75

13

......

2.2

7 9

5.4

52

4.

85

69

16

2.9

6.7

4.8

50

5.

93

81

12

......

2.6

1.2

2.7 fin

......

6.

92

9.2

3.8

3. 8

1.9

7.

109

90

19

6.9

.18

3.8

7.2

8.

52

45

17

1.76

.97

.94

1.10

"9.27

1.024

9.

64

56

8

2.08

1.26

.90

1.36

all. 10

1.028

a Exclusive of the organic S.

No. 1, by the writer, is the average of two analyses of waste liquor 

collected directly from the digester at the Mechanicsville mill. Nos. 

2 to 6, inclusive, are quoted by Hoffmann,tt Nos. 2, 3, 4, and 5 being

oHoflmann, C., Practisches Handbuch der Papier Fabrikation, Berlin, 1897.
SULPHITE PULP WASTE LIQUOE. 21

by Wickelhaus,a and No. 6 by Lehman. No. 7 is given by Schubert,6 

and Nos. 8 and 9 are taken from the notebook of S. C. Lindberg, 

paper-mill chemist, who has kindly permitted their use.

These analyses give an excellent idea of the general character of 

the liquid. The proportions of the various constituents are in agreement with the figures which have been calculated from the amounts 

of raw materials used. The analyses also determine satisfactorily 

the nature of the inorganic matter in the waste and show the relatively large amount of organic matter present, about 80 per cent of 

the total solids.

CHEMICAL NATURE OF THE ORGANIC MATERIAL.

Thus far only the total amount of waste material in the liquor 

resulting from the digestion of 1 ton of dry pulp and its division into 

organic and inorganic constituents have been considered. The chemical nature and the essential characteristics of the organic matter 

deserve further consideration. Though our knowledge of the chemistry of wood is not extensive, the following facts seem to be definitely settled and may be accepted as embodying all that is positively known. The wood substance itself, freed from the relatively 

small amount of intercellular matter, such as gums and sap constituents, is a homogeneous material of fairly constant composition. 

To this substance chemists have given the name ligno-cellulose. Lignoce lulose can be broken down by suitable chemical treatment into 

two or more substances. These are cellulose, which is the material 

oi the wood pulp, and a complex substance or mixture variously 

called lignose, lignin, or lignone. It is this latter body or mixture of

dies which in the sulphite process is supposed to be sulphonated, 

giving rise to a substance known as lignon-sulphonic acid. The constitution of this substance is not known, nor is its chemical identity 

even assured. Beyond these meager facts all is hypothesis, despite 

the large amount of experimental work which has been done on the

^stance under discussion. Probably the best estimate of the

aracter of lignone is given by Cross and Bevan,c who made an

laustive study of the subject.

They conclude that it is a single substance made up of (a) 2C18H18O10 , 

setone transitional to quinone which chlorinates directly to margallol; (&) 6C5H4O2 , furfural, in combination by condensation with 

and (c); and (c) 5C3H4O, acetic residue. The simplest empirical 

mula for their lignone is (C6H6O3 )n, n being not less than some

Papier Zeitung, 1895, No. 38.

6 Schubert, Max, Die Cellulose Fabrikation, Berlin, 1892. 

>oss, C. F., and Bevan, E. J., Contributions to the chemistry of ligniflcation: Jour. Chem. Soc., vol.

15, rans., 1889, p. 199.
22 POLLUTION OF STREAMS BY SULPHITE PULP WASTE.

multiple of 24. Tollens a gives as the result of his analysis of the 

sulphonated form the empirical formula 

C24H2307 (OCH3 ) 2 .(S03H).

This formula must be slightly modified in view of Cross and Bevan's 

satisfactory determination of the presence of 5 acetic residues in the 

C76 molecule, instead of 6, as given by Tollens's formula. It has been 

stated that the chemical identity of the sulphonated form has never 

been satisfactorily shown. The experimental work on sulphite liquor, 

conducted by the author, seems to prove that the substance in question is probably not a true sulphonic acid.

PURIFICATION OF SULPHITE WASTE LIQUOR.

Investigations on the disposal of waste liquors may be carried out 

either with the object of recovering and utilizing the material contained therein or with the simpler aim of purifying the liquid so that 

it may safely be discharged into a stream. The former method of 

investigation has appealed most strongly to manufacturers and chemists, and a great many attempts have been made to discover some 

useful by-product in the waste sulphite liquors. Reference to these 

investigations will be made later. Owing to the failure in general of 

all such attempts and to the stringent laws against stream pollution, 

particularly in Germany, some attempts have also been made simply 

to purify the liquor by precipitating the organic matter, the experiments having no reference to the recovery of valuable by-products. 

One of the earliest of these investigations was made by H. Frank, 6 

who gives the following composition of the sulphite waste which he

used:

Composition of sulphite waste.

Grams per liter.

Total solids................................................... 82

Loss on ignition................................................ 59

Ash........................................................... 23

Calcium(Ca)............................................... 5. 3

Magnesium (Mg).......................................... .25

Sulphate radicle (S04)...................................... 14.4

In the process developed by Frank the liquor is treated first with 

lime to neutralize the free acid and then with chimney gases to carbonate the excess of lime and oxidize the calcium sulphite. A heavy 

precipitate of sulphate and carbonate is formed and it is claimed 

that much of the organic matter is dragged down, so that the supernatant liquid could be discharged into the stream. This process 

was later investigated more thoroughly by F. B. Ahrens, E. Klingstein, and P. Schubert, c who state that many German wood-pulp

a Quoted by Cross and Bevan, Researches on cellulose, p. 126. 

6 Wien. Jahresbericht, 1887, p. 1177. 

c Zeitschr. angew. Chemie, 1895, p. 41.
SULPHITE PULP WASTE LIQUOE. 23

mills have been compelled to close because it was found impossible 

to comply with the requirements of rivers-pollution officials. The 

examination of the waste sulphite liquor which they used showed 

that it gave a strongly acid reaction, had a specific gravity of 1.0465 

at 15.8° C., and was optically inactive. The dry residue was 9.4 per 

cent, of which 1.11 per cent was ash and 8.29 per cent organic matter 

not strictly accurate determinations. The liquors from the digesters 

were nearly neutralized by passing them over limestone. The hot 

lye was then mixed with a known quantity of fresh lime water once 

boiled, filtered, and the filtrate neutralized with carbonic-acid gas. 

The results obtained are shown in the following table:

Results of experiments in neutralizing hot sulphite waste liquors.

CaO

added.

Per cent.

2

3

4

5

6

7

8

9

10

11

12

15

20

30

Analysis of supernatant

liquor.

Dry substance.

Per cent.

8.75

7.48

7.36

7.13

6.86

6.74

6.65

6.61

6.79

6.54

6.52

6.31

7.00

4.99

Ash.

Per cent.

1.80

1.59

1.71

1.56

1.52

1.58

1.54

1.57

1.51

1.55

1.49

1.49

1.60

1.01

Organic 

matter.

Per cent.

 6.95

5.89

5.65

5.57

5.34

5.16

5.11

5.04

a 5.28

4.99

a 5. 03

4.82

a 5. 40

3.98

a Organic matter rendered soluble again by boiling.

When the liquors were treated cold, the following results were 

obtained:

Results of experiments in neutralizing cold sulphite waste liquors.

CaO 

added.

Per cent. 

2 

3 

4 

6 

8 

10 

12 

14

Analysis of supernatant 

liquor.

Dry substance.

Per cent. 

6.21 

6.19 

5.26 

5.08 

4.96 

5.67 

5.76 

6.26

Ash.

Per cent. 

1.11 

1.33 

1.00 

1.04 

1.10 

1.22 

1.23 

1.29

Organic 

matter.

Per cent. 

5.10 

4.96 

4.26 

4.04 

3.86 

4.45 

4.53 

4.97

Sodium aluminate was also tried as a precipitant, but the results 

were less satisfactory. The precipitated and neutralized liquors were 

then treated electrically. A current of 5 amperes and only sufficient
24 POLLUTION OF STEEAMS BY SULPHITE PULP WASTE.

potential was passed through the liquid between platinum electrodes, 

but no diminution in either mineral or organic matter was observed 

after two hours. A high-tension current (106 volts) was then tried, 

but the results were equally ineffective after a test of the same duration. It is evident, these authors conclude, that the objectionable 

organic matter, if removable at all, calls for some process hitherto 

undiscovered. Ahrens tried, unsuccessfully, to treat this waste bacterially after neutralization on the lines of his patent. It was found 

absolutely sterile to begin with, and the amount of bacterial filtration required for its decomposition was altogether impracticable. 

E. Bruch" found that if the waste liquors are treated when acid, or 

neutral, with leather glue, a compound of tannic acid and glue is 

formed which coagulates on storing and becomes highly viscid. If 

then the clear, colorless top liquor is decomposed with aluminum 

sulphate, another gummy precipitate is formed. Both precipitates 

are soluble in alkalies and in weak ammonia, and may be removed, 

dried, and powdered. If the clear liquor is then neutralized with 

chalk or lime, a precipitation and clarification ensue, and the top 

liquor is free from smell and has lost about 25 to 30 per cent of the 

total organic constituents, and these the most easily decomposable.

UTILIZATION OF SULPHITE WASTE LIQUOR.

By far the most important work on this waste liquor has had for 

its object the utilization of the organic matter. Its complex chemical nature and relatively large amount and the fact that it is still 

a chemical mystery make the field particularly inviting for research. 

In some interesting laboratory experiments made by Buddens, 6 

and quoted by Griffin and Little,6 the waste liquor was neutralized 

by ammonia, the lime was precipitated by ammonium carbonate, 

and the carbonate of lime thus formed was separated by filtration. 

The dark-brown filtrate was evaporated and the dried residue distilled. The dried residue contained 7.2 per cent of ammonia as 

salts. Water and a yellow oil were obtained in the condenser, and 

finally a crystalline sublimate appeared on the walls of the tube. 

The escaping gases were caught in a gasometer. The oil had at first 

a mercaptan-like odor, but this disappeared on heating slightly. 

The odor was without doubt due to organic sulphur compounds, 

which were present in traces. The mixture of oil and water was, 

after this heating, distilled with steam, the distillate was shaken out 

with ether and then dried, and the ether was evaporated over calcium chloride. The brown oil that remained boiled at 130° C., and 

as it colored a pine chip moistened with hydrochloric acid a strong

a Die Abwasserreinigung der Cellulose-Pabriken und die Papierleimung: Chem. Zeitung, 1892, p. 1782.

&Buddens, W., Papier Zeitung, March, 1891.

c Griffin and Little, Chemistry of paper making, New York, 1894.
SULPHITE PULP WASTE LIQUOR. 25

carmine, it was believed to be pyrrol. Pyroeatechin was also found 

in the distillate, as was proved by color tests with iron salts and by 

the reduction of Fehling's solution. The gases from the first distillation were carbon monoxide, hydrogen, mar^h gas, and hydrogen 

sulphide. Four hundred grams of the residue yielded 180 grams of 

coke, 30 liters of gas, and 200 grams of distillate. Mucic and saccharic acids could not have been present as such in the liquor, because 

they are formed by the oxidation of carbohydrates, and the action 

of the liquor is a reducing one. Yet pyrrol is formed by distilling 

the ammonium salts of these two acids. The only way of accounting 

for pyrrol is by considering that succinic acid is formed from the 

resins in the wood a not improbable assumption. Ammonium 

succinate changes readily into ammonium succinamide, which gives 

pyrrol when it is heated with reducing agents. The presence of 

pyrocatechin is due to the presence of dioxybenzoic acid (1, 3, 4), 

which is in the liquor as dipyrotechnic acid. The decomposition of 

this acid by distillation with ammonia produces tannic acid and 

pyrocatechin. Doctor Buddens states that there is no tannic acid 

in the liquor, which will give a blue-black color with ferric chloride, 

because the tannin in wood is reduced by digesting with sulphurous acid. The reduction is probably due to dipyrocatechuic 

acid, but by treating the liquor with ammonia and distilling, tannic 

acid is eventually formed. Sulphites are oxidized to sulphates when 

the tannin is reduced. It is possible, therefore, that the difficulty 

of pulping wood rich in tannin by the sulphite process is due to the 

action of the tannin, which renders the sulphurous acid ineffective. 

Lindsey and Tollens,ffl in their systematic search for the different 

sugars, used liquor from a Mitscherlich slow-process cook, with a 

specific gravity of 1.055, showing total solids 9.5 per cent, and calcium 0.41 per cent. The solution was pale yellow in color and 

strongly reduced Fehling's solution. They found no evidence of the 

presence of saccharose, dextrose, or dextrose-yielding sugars, traces 

only of levulose or levulose-yielding sugars, and btit a small amount 

of galactose. On the other hand, mannose, determined as a hydrazine, was found to represent 6 to 7 per cent of the original total solids. 

Furfural was found in some quantity on heating with hydrochloric 

acid, and xylose was identified in the solution. Alcoholic fermentation of the liquor gave amounts of alcohol corresponding to only 

1.2 per cent of the total carbohydrates. The remaining gummy 

mass behaved as a homogeneous complex, yielding several synthetic 

preparations, the analyses of which were consistent with the view 

of its homogeneity.

a LieMg's Annalen, No. 267, 1892, p. 341. Abstracts Jour. Chem. Soc., 1892, p. 802.
26 POLLUTION OF STREAMS BY SULPHITE PULP WASTE.

A summary of various attempts to recover valuable products from the 

waste has already been given (pp. 15-18). Thus far no satisfactory 

recovery of valuable chemical substances has been made. The substance itself has been used as a substitute for glue and for sizing. 

Mitscherlich precipitated the tannin compounds with glue in the 

presence of alum and sulphuric acid, obtaining a rubbery mass, soluble in weak alkali, which could be used in engine sizing. He later 

improved the process a by precipitating with lime to remove the 

sulphite present and then diffusing the liquor through membranes. 

The diffusible portion contained sugars and was fermented for alcohol. The nondiffusible part was treated as described above in order 

to remove the tannins. A later patent 6 describes a process in which, 

after the removal of the calcium salts, the liquor is heated with hair 

or bone to give a semiwaterproof sizing. V. Drewnen and L. I. 

Dorenfeldt c treat the liquor with soda ash recovered from the soda 

pulp process, precipitating the lime and a part of the organic matter. 

They draw off the clear liquor and burn the residue, using the heat of 

the combustion to evaporate more liquor. The liquor is said to contain more calorific energy than is necessary to evaporate it. The 

soda ash is recovered from the residue by the usual process, and 

about 60 per cent of the sulphur is recovered by liberating free sulphur dioxide with carbon dioxide gas. The fumes and the gases from 

the evaporation were found to be very corrosive. This trouble was 

finally overcome by combining the wastes of the sulphite and soda 

pulp mills and treating them like soda wastes. Frank's process, as 

described by Schubert/ consists in precipitating the remaining calcium bisulphite as normal sulphite with excess of lime, after which 

the precipitate is redissolved in an excess of sulphur dioxide. Such 

treatment would recover only a small part of the total sulphur. 

Meyer's process, also described by Schubert, 6 seeks to recover valuable products by destructive distillation of the organic material in the 

waste. The liquors are neutralized, concentrated to a thick sirup, 

mixed with charcoal to a paste, and distilled. The yield of valuable 

products is too small to make the process economical. H. Seidel 

has employed the soda salt of the lignone sulphonic acid as a reducing agent in chrome mordanting wool, where, under the name "lignorosiii," it is used in place of tartaric and lactic acids/ The material, especially when concentrated, is very sticky, and many attempts 

have been made to utilize it as a substitute for glue. In J. S. Robea United States patent No. 681241, 1901. 

b United States patent No. 687844, 1901. 

c United States patents Nos. 620755, 1899, and 726036, 190?. 

d Schubert, Max, Die Cellulose Fabrikation, Berlin, 1892. 

e Op. cit.

/ Rev. g6n. des mat. col., vol. 2,1898, p. 370. Jour. Soc. Cnem. Ind., vol. 17,1898, p. 1043. British patent 

No. 19005,189V. German patent No. 99682, 1897.
EXPERIMENTAL INVESTIGATIONS. 27

son's process a for the manufacture of an adhesive, which is being 

used at Ausable Forks, N. Y., by a large mill, 6 the waste liquor is 

neutralized with lime and evaporated in vacuo. The product is a 

thick, molasses-like fluid, which finds application in foundries as an 

adhesive in core making. C. H. Voight c makes a glue substitute by 

heating starch and a peroxide with the sulphite liquor. A. G. Brooks d 

evaporates the liquid till it contains 20 per cent water, then adds 

carbohydrates or albuminoids and dries the mass, which is used for 

fuel, pitch, glue, resin, or size. Knoesel 6 concentrates to 25° B. 

and treats with a slag meal high in phosphorus (Thomas slag). It 

is claimed that the phosphorus of the slag is rendered soluble in 

citrates and becomes available in fertilizing. Ahrens/ investigated 

the process and could not substantiate its claims. Processes have 

been proposed for the destructive distillation of the substance, and, 

as has already been stated, both pyrrol and pyrocatechin have been 

obtained in this manner. The yield of these products has not been 

sufficient to make the process successful. Patents have been granted 

for processes involving the use of the liquor in tannin.6' According 

to Seidel ft 28 per cent of the solids are removed by rawhide powder. 

No satisfactory method has yet been described for separating the 

tannin substance from the remainder. This seems to be one of the 

important lines for future investigation. Morterad* subjects the 

hot liquors to a partial vacuum and removes from them a considerable 

volume of sulphur dioxide. Bergerhopf-' made a cheap grade of 

paper for newspapers by using the waste liquors to digest sawdust. 

Eckman fc "salts out" the liquors and makes a concentrated solution, which he calls "dextrone," a substitute for dextrin, or British 

gum.

EXPERIMENTAL INVESTIGATIONS WITH THE ORGANIC

MATERIAL.

The knowledge of the chemical reactions which characterize lignone 

is very meager. Early in the present study it was deemed important 

to obtain additional light on the general behavior of this material. 

It was hoped that in this way knowledge of its chemical nature might 

be enlarged and particularly that some reactions of industrial value

a United States patent No. 833634, 1906. 

6 Paper Trade Journal, Jan. 5, 1905, p. 12. 

c United States patent No. 770202, 1904. 

d British patent No. 8088, 1901. 

e Jour. Soc. Chem. Ind., 1902, p. 489.

/ Chem.Zeitung, vol. 4,1905, p.40, Chem. Centralbl., vol. 1, 1905, p. 700. Jour. Soc. Chem. Ind., vol. 14, 

1905, p. 343.

Q German patent No. 72161. 

h Zeitschr. angew. Chemie, 1900, p. 951.

* United States patent No. 833936, 1906.

1 German patent No. 160651, 1903. Jour. Soc. Chem. Ind., vol. 24, 1905, p. 1028.

* German patent No. 81643.
28 POLLUTION OF STREAMS BY SULPHITE PULP WASTE.

might be discovered. For this study preparations of the dry material 

were made in various ways; the solubility of these preparations was 

investigated; attempts were made to identify a sulphonic acid in the 

material; and various other reactions were studied.

PREPARATION OF CRUDE " LIGNONE."

Three different preparations of the dry material were used. "Lignone A" was obtained in dry form at the mill. It was observed that 

certain steam pipes passing near the blow pit were heavily coated with 

a hard vulcanite-like substance, nearly an inch thick in places. About 

a pound of this material was chipped off and used in certain of these 

experiments. "Lignone B" was the supposed calcium compound 

obtained by evaporating the liquor to one-half volume and salting 

out with common salt. A granular amorphous substance, containing some salt and moisture, was obtained. "Lignone C" was 

supposed to be the sodium compound. When the liquor was neutralized with sodium carbonate and allowed to settle, a large amount of 

calcium carbonate was precipitated. The remaining liquor was 

evaporated and salted.

SOLUBILITY OF CRUDE "LIGNONE."

The solubility of each of these preparations was tested with several 

solvents in an endeavor to obtain a liquid from which the material 

could be crystallized. No solution took place in either hot or cold 

benzoin, amyl alcohol, allyl alcohol, petroleum ether, amylene, amyl 

acetate, aniline, toluene, xylene, nitrobenzene, carbon bisulphide, 

ethyl ether, or benzol. Benzoin seemed to soften the substance. 

The tests were repeated after acidifying to see if a free acid could be 

found which would dissolve, but the results were again negative. The 

two alcohols dissolved the samples if diluted with water. Ordinary 

ethyl alcohol also dissolved it, a result probably due to the water 

present. Absolute ethyl alcohol was not tried.

REACTIONS WITH PHOSPHORUS CHLORIDES.

An important general reaction of sulphonic acids is that with 

phosphorus pentachloride, giving sulphon-chlorides according to the 

reaction 

R.SO2 .OH + PG15 = R.SO,.C1 + POC13 + HC1.

Sulphon-chlorides are for the most part insoluble oils which combine with ammonia to form crystallizable sulphonamides, as follows:

R.SO3 .C1 + 2NH3 = R.SO2 .NH, + NH4C1.

Appropriate mixtures of the crude " lignones " with varying amounts 

of the pentachloride, the oxychloride, and mixtures of the two were 

made. No indication of any reaction was obtained at room tempera-
EXPERIMENTAL INVESTIGATIONS. 29

ture or at temperatures up to 180° C., at which point the oxychloride 

begins to distill. Altogether about twenty attempts were made to 

bring about this reaction. The products after heating were treated 

with ammonia, but no evidence of any amide was ever obtained. 

It must be concluded, therefore, that the "lignone" does not react 

with the chlorides of phosphorus in the way which characterizes 

sulphonic acids in general.

FUSION WITH ALKALI.

Another characteristic of sulphonic acids is their ready reduction 

to corresponding phenols on fusion with caustic alkali according to 

the reaction 

Preparations of "lignone" were fused in this way, the resulting 

masses being extracted with ether and evaporated. Only mere traces 

of ether extract were obtained, and these gave none of the usual tests 

for phenols. During the fusion the sulphur gave strong evidence of 

its escape into the air in the form of some volatile mercaptan, with a 

very penetrating and sickening odor.

POSITION OF THE SULPHUR IN "LIGNONE."

As in both series of tests just described the "lignone" failed to 

react in a way characteristic of true sulphonic acids, the presumption 

is reasonable that a sulphonic acid is not present. An interesting 

question is therefore raised. How is the sulphur in this material 

related to the molecule 1? In the salting-out experiments some light 

was thrown on this question. It was found that a considerable part 

at least of the sulphur was in such loose combination that it was given 

off as sulphur dioxide in the cold during the salting process. The 

result when first observed was attributed to the sulphur dioxide in the 

liquor, but it was possible to show that such was not its origin. A 

small amount of the fresh liquor was cautiously evaporated nearly to 

dryness and then diluted with water to the original volume. This 

solution was then salted in parallel with a fresh solution. As nearly 

as could be determined by the sense of smell, equal amounts of 

sulphur dioxide were given off by both samples. Confirmatory 

results were obtained by dissolving some of "lignone A," a completely dried sample, and treating it in the same manner. That all 

the sulphur could not be removed by this procedure was evident on 

drying and igniting the salted sample, when the same disgusting odor 

was given off as by the original sample and apparently to the same 

degree. This point was verified quantitatively by titration with
30 POLLUTION OF STEBAMS BY SULPHITE PULP WASTE.

iodine solution. When the solution was acidified, an evolution of 

sulphur dioxide occurred and the reducing power increased from an 

equivalent of 0.01 per cent to 0.104 per cent of sulphur dioxide. On 

continued boiling without acid the reducing power increased from 

0.011 to 0.015 per cent of sulphur dioxide. Boiling with potassium 

hydrate still further increased it to 0.201 per cent. Lime water had a 

similar but less marked effect. All these observations point to the 

probable fact that a sulphurous ether is present. Such ethers yield 

sulphur dioxide to sulphuric acid and are readily hydrolyzed by an 

alkali. The results here obtained are, in all respects, what would be 

expected from sulphurous ether, and the presence of a sulphonic acid 

has not been verified. Though the presence of the latter compound 

has not been disproved, the writer is strongly of the opinion that the 

major part, at least, of the sulphur is present in the form of an acid 

sulphurous ether of some complex hydrocarbon radicle.

REACTIONS WITH AROMATIC AMINES.

Previous investigators have generally agreed that "lignone" 

possesses aldehydic properties. A characteristic property of aldehydes is that of forming condensation products with certain bodies; 

the aldehyde and the other substance aniline, for example condense to form a complex molecule. When a solution of "lignone" 

was mixed with aniline, a bright-red precipitate was formed. An 

excess of aniline changed this body to a black insoluble gum. The 

reaction took place equally well with aniline oil or with aniline sulphate. All attempts to purify the product failed. It was insoluble 

in all solvents except acids, which apparently decomposed it into its 

original constituents. Reference will later be made to the action of 

strong nitric acid on the gum. Exactly similar condensations were 

observed with the following: Ethyl aniline, diethyl aniline, dimethyl 

aniline, methyl diphenylamine, m-chloraniline, ^-chloraniline, dichloraniline (1-2-4), w-nitraniline, p-nitraniline, o-toluidine, p-toluidine, dibrom-o-toluidine, o-tolidine. Substituted amines which did 

not give condensations were o-nitramline and dinitraniline (1-3-5). 

Bright-red products were formed in every case where the amine 

retained the NH2 group. With amines in which substitution had 

taken place in that group brown or black compounds were formed. 

The reactions of these preparations with fused sodium sulphide is 

considered under the caption "Sulphur dyes." As in the case of 

the aniline condensation product, it was not possible to purify these 

gummy substances. They were decomposed into the original constituents on treatment with strong acids or generally on heating.
EXPERIMENTAL INVESTIGATIONS. 31

REACTIONS OF THE AMINE CONDENSATION PRODUCTS WITH

NITROUS ACID.

On the assumption that the condensation products still retain 

their characteristic amine group, they were treated with nitrous acid 

in an ice bath, in the hope of obtaining some 'new bodies through 

the diazo reaction. In the case of aniline this reaction is 

C6H5NH2 .HC1 + NO2H = C6H5N: NC1 + 2H2O.

When this substance alone is heated it decomposes, yielding 

phenol, but in the presence of other substances, such as some unaltered aniline, reactions of technical importance can be brought 

about:

C6H5N: NC1 + H2O = C6H5OH + N2 + HC1, 

or C6H5N: NC1 + NH2C6H5 = C6H5N: N.NHC6H5 + HC1.

The product of the latter reaction is diazo-amidobenzene, a starting 

point for the preparation of an important group of dyes. Application of the diazo reaction to the condensation products above 

described did not generally result in apparent change. In some 

experiments an excess of the amine reacted in a manner quite characteristic of the amine itself without any substituted groups. The 

general inertness of these bodies under such conditions leads to the 

conclusion that substitution takes place in the amido group of the 

condensation products. This is further verified by the fact previously shown, that all primary amines gave bright-red condensation 

products, while the others gave brown or black substances.

REACTIONS WITH NITRIC ACID.

Concentrated nitric acid was found to have a very vigorous action 

on the dry "lignone" preparation and on the sulphite liquor itself at 

high temperatures. The organic matter of the dry "lignone" is 

completely oxidized, chiefly to oxalic acid, in the presence of a sufficient excess of the acid. Nitrous acid fumes are evolved, and the 

odor of acetic acid can be distinctly detected. The action of nitric 

acid on the waste liquor is less violent. When a mixture of one part 

strong acid and ten parts of liquor is warmed, action begins at once. 

Nitrous and acetic acids are evolved, as with the dry product, and 

the color of the solution changes from dark brown to bright, golden 

orange. This solution, after neutralization of the free nitric acid by 

an excess of sodium acetate, was found to dye wool and silk a beautiful orange-yellow. This yellow dyestuff, which for convenience 

may be called lignone yellow, is of peculiar interest as a product to 

be recovered that may be valuable, and it was therefore carefully 

studied.
32 POLLUTION OF STREAMS BY SULPHITE PULP WASTE.

LIGNONE YELLOW.

Difficulty was at first experienced in separating the dye from ih°> 

liquid. Cloth could be dyed directly in the liquid with excellent 

results, but on evaporation the dye lost a great deal of its coloring 

power. By evaporating it in partial vacuum to a thick sirup and 

then reducing it to dryness in a warmed vacuum desiccator, it wa« 

finally possible to obtain the desired material in dry form. It is a 

light-yellow powder, very porous, and extremely hygroscopic, which 

latter property considerably diminishes its commercial value.

Samples of woolen cloth dyed in baths prepared from the dried 

material in the proportion of 2 per cent of the dye, by weight, wero 

very beautifully colored. The color is retained on boiling for half 

an hour in soap solution, dilute acetic acid, or dilute alkali. It withstands the action of bleaching powder, chromate, and other oxidizing 

agents. It will stand direct summer sunlight for two days without 

apparent discoloration, but it is affected on the third day; so it is, 

therefore, only moderately fast to sunlight.

Lignone yellow is exceedingly soluble in water and in ethyl alcohol. 

On evaporation of these solutions it yields a pasty mass which i? 

completely dried with difficulty. When dried at 100° C., it is decomposed with evolution of nitrous oxide. It can be eventually oxidized 

with nitric acid to oxalic acid. From the manner of its formation it 

might be thought to be a iiitro-body and in its dyeing properties it 

resembles picric acid; but it differs from the latter and from other 

nitrophenols in several particulars. Picric acid, or tri-nitrophenol, 

crystallizes from hot water and is difficultly soluble in cold water. 

The same is true of para-nitrophenol. Ortho- and meta-nitrophenols 

melt at 45° C. and 96° C., respectively. The three dinitrophenols arc 

converted to picric acid 011 further nitration. If lignone yellow is an 

aromatic nitre-body, it must be more complex than any of the nitrophenols. Repeated attempts to reduce this dye were made, but no 

amiclo-bocly could be detected after attempted reduction with zincdust, zinc and hydrochloric acid, iron and sulphuric acid, ammonium 

sulphide, hydrogen sulphide, or the electric current. In no case die1 

nitrous acid bring about any reaction after these attempts at reduction. Generally, the yellow color was not destroyed. Neither weak 

chromic acid nor bleaching powder destroy the color. Long-continued boiling of the original sulphite liquor with sodium nitrite gives' 

a liquor with feeble dyeing properties, the color being like that of the 

nitrated substance. It is possible,. therefore, that the dye is a 

nitroso-compound of some complex radicle rather than a nitro-body. 

All attempts to prove this point resulted negatively and the question 

of the fundamental character of the dye remains open.
EXPERIMENTAL INVESTIGATIONS. 33

REACTIONS OF THE AMINE CONDENSATION PRODUCTS WITH

NITRIC ACID.

It was thought that the nitration of the substances produced by 

the condensation of the "lignone" substance with various amines 

might give rise to dyes of different character, and that the latter might 

have technical value as well as furnish some clue to the nature of lignone yellow. Accordingly, the different condensations described 

under "Reactions with aromatic amines" (p. 30) were submitted to 

the action of dilute nitric acid and the dyeing properties of the 

resulting solutions were tested on samples of wool. To obtain comparative results, the same quantities of the various components were 

used each time. As many of the amines are themselves capable of 

easy nitration under suitable conditions, a blank test was made each 

time, the amine tested being used without any sulphite liquor. The 

results of such blank tests as gave a dya in any way similar to that 

resulting from the condensation product are not recorded as positive. 

In each test approximately one part of the amine and one part of 

nitric acid were used with twenty parts of the sulphite liquor. The 

results of the tests are summarized in the following table:

Nitration of products resulting from the condensation of "lignone" and amines; wool

dyed in resulting liquors.

Amine.

m-Nitraniline. ............................

Color of dye produced.

Golden orange. ..............

Intensity of 

color!

Weak.........

Weak.........

Weak.........

Strong. .......

Weak.........

Color of blank.

Colorless.

Pale pink.

Colorless.

With the exception of one or two doubtful cases, it appears that the 

condensation products enter into reaction with nitric acid just as 

"lignone" alone does, and that the shade and intensity of the dyes 

produced by the reaction vary from green through orange and yellow 

to brown, depending on the nature of the amine that is used. Some 

general observations can also be made from this study. Substitution 

in the amido group of ethyl aniline, etc., gives greenish shades, and 

the lighter the substituting groups the more pronounced the green. 

In mono-substituted aniline, the para-compounds give the most bril-
34 POLLUTION OF STREAMS BY SULPHITE PULP WASTE.

liant and powerful dyes, and then in decreasing brilliancy the metaand the ortho- compounds. The most powerful and brilliant dyes of 

the series in the table were those produced by ^-chloraniline, p-nitraniline, and £>-toluidine. Chlor-compounds give the most brilliant dyes; 

the nitro-compounds give dyes of more strength and body. As with 

the nitrated "lignone" alone, here also every attempt failed to produce amines from their nitrated substances. Many of the products, 

it is true, gave a reaction with nitrous acid after reduction, but in all 

such cases the reaction was that of the amine originally used and the 

resulting substances could be prepared equally well without the addition of "lignone." Reduction of the nitraniline products was not 

attempted, as too great complication would arise from the presence 

of the nitro-groups known to be present.

SULPHUR DYES.

Many organic substances yield dyes when fused with a mixture of 

sulphur and sodium sulphide. These so-called sulphur dyes are now 

manufactured in a variety of colors. They are direct cotton dyes 

that is, they dye cotton without the aid of a mordant and they are 

very fast. Their cheapness and valuable properties have caused 

them to come into wide use. An attempt was made to prepare dyes 

of this kind from sulphite waste liquor and from several of its condensation products. In particular, it was hoped to obtain dyes of 

bright color, red or blue, because such colors are especially desirable 

and bring good prices on the market. Brown and black are much 

more readily made, and are consequently cheaper. Mixtures of one 

part dry crude "lignone" and one-half part each of sodium sulphide 

and sulphur were fused for fifteen minutes at a low heat. The 

resulting mass was extracted in hot water and the extract filtered and 

evaporated. From 25 grams of dry "lignone" there were made 20 

grams of a green powder, soluble in water containing a little sodium 

sulphide. This powder was found to be a true sulphur dye, coloring 

cotton a dark green, which changed to a good black on oxidation in 

the air or on subsequent treatment in a chrome bath. Compared 

with commercial dyes in the market, this dye is worth about 7 cents 

a pound in its impure condition. About half its weight is inert material, which can be removed by proper treatment. Similar experiments in preparing sulphur dyes were made with the condensation 

products previously mentioned. (See p. 33.) The shades of the 

resulting dyes were somewhat modified by the presence of the amine, 

but they were all browns, grays, or black. No advantage was apparent in the use of the condensed products over that of the untreated 

"lignone."
CONCLUSIONS. 35 

COMMERCIAL POSSIBILITIES OF LIGNONE DYES.

Two of the best dyes, namely, those resulting from the nitration of 

"lignone" alone and of "lignone" condensed with p-chloraniline, 

were prepared in large quantity, in order to determine the yield and 

the cost of the process. One hundred grams of dry crude "lignone" 

were treated with 50 cubic centimeters of concentrated nitric acid 

(specific gravity 1.42), and the resulting solution evaporated in vacuo. 

Seventy grams of lignone yellow were obtained. Compared with 

mandarin yellow, the technical dye approaching it most nearly in 

color and fastness, it is worth 18 cents a pound. The cost of nitric 

acid would be 5 cents a pound of dye. To neglect for the moment 

the cost of evaporating the original liquor, the margin between the 

cost of the acid and the value of the dye appears to be sufficient to 

pay for the work of handling. This would be true at places where 

expediency makes it necessary to evaporate the liquor in any case, 

and also at places where the dye could be used in liquid form 

as made. The cost of evaporating the liquor, however, would 

undoubtedly be greater than the value of the dye. It must also be 

borne in mind that there is necessarily a limited market for a dye of 

this kind a market too limited, in fact, to permit any general adoption of this plan of utilization, even if it were very much cheaper. A 

similar test of the cost, yield, and value of the dye from p-chloraniline 

gave an additional cost of 9 cents a pound of dye for aniline, making 

the total cost for material 14 cents a pound. While the color was 

much more brilliant, its red shade lowers slightly its market value, 

pure yellows and greenish yellows being in much greater demand for 

use thaft browns. As an additional market outlet, however, this dye 

may possibly help in the utilization of sulphite waste liquor. The 

actual results attained in this investigation are not considered so 

important as the fact that a new and interesting series of reactions 

of "lignone" have been discovered. Further development of these 

dyes is the work of the skilled expert in textile coloring. It is not too 

much to expect that such an expert, possessing full knowledge of the 

technique of dyeing, will be able not only to simplify and to reduce 

to a practical working basis the methods herein outlined, but also to 

discover new and more valuable products by further experimentation 

along similar lines.

CONCLUSION.

The foregoing study of sulphite pulp waste liquor and of the possible utilization of the organic material in it may be summarized in a 

few sentences.

Stream pollution by the waste from sulphite pulp mills is extensive 

and wasteful; every year over two and a half billion pounds of solid
36 POLLUTION OF STREAMS BY SULPHITE PULP WASTE.

matter from this source are turned into the rivers and lakes of the 

United States.

The problem of utilizing this immense amount of waste matter has 

been studied for a long time, and numerous processes for using or for 

destroying it have been devised, but they are all unsuccessful, either 

because there is only a limited market for the proposed product or 

because the suggested process is prohibitively costly.

Successful disposal of the sulphite waste liquor lies obviously in the 

utilization of the so-called "lignone" in it, but aside from the employment of this substance to a slight extent as an adhesive and as a source 

of tannin, no practicable way for its direct use has been devised.

The waste consists principally of wood material separated from the 

wood fiber by the action of a strong sulphite solution on wood chips; 

it is a compound of "lignone" with sulphur; but the exact nature of 

the union has not been definitely demonstrated.

Experimental evidence indicates that the sulphur-bearing compound in the waste liquor is not a true sulphonic acid; at all events, 

it does not react like an ordinary sulphonic acid. Its condensation 

with the aromatic amines point to its probable aldehydic nature.

Nitration of "lignone" and of its amiiie condensation products? 

gives a series of dyes the shade and intensity of which vary from 

green through orange and yellow to brown, depending on the nature 

of the amine that is used. These substances dye wool directly, giving 

brilliant colors that are fast to soap, acids, and alkalies, and reasonably 

fast to sunlight. One of them, named lignone yellow, and made by 

nitrating crude "lignone" itself, dyes wool and silk a beautiful orange 

yellow. Fusion of ' 'lignone " with sodium sulphide and crude sulphur 

produces a sulphur dye that colors cotton dark green, changing to 

black on treatment in a chrome bath.

A search for new compounds, such as that made in the present 

investigation, possesses the serious drawback that much time and 

effort may be spent without tangible results; on the other hand, an 

important discovery may be made at any time. Certain reactions 

brought to light in this work with "lignone" reveal great possibilities. 

Though the dye called lignone yellow has only slight commercial 

possibilities and is at best but a partial solution of the major problem, 

yet the opportunities for further progress along this line are pregnant 

with the ever-present chance of discovering valuable substances. 

The number of "lignone" condensation products is almost unlimited, 

and a wide field for investigation is thereby offered. Only a small 

portion of a large and interesting territory has been covered by these 

experiments and the results are by no means conclusive. But it is 

hoped and expected that the mere reopening of this old and practically 

abandoned problem by calling attention to these new lines of attack 

may result in renewed investigation and in the ultimate utilization 

of a substance that to-day is probably the most valuable waste material 

known to industrial chemistry.
SURVEY PUBLICATIONS ON STREAM POLLUTION.

The following water-supply papers of the Survey discuss stream 

pollution. Nos. 103,152,185, and 194 can be obtained from the Super- 

 'ntendent of Documents, Government Printing Office, Washington, 

D. C., at the prices stated. Any of the others will be sent free, while 

the edition lasts, on application to the Director of the United States 

Geological Survey.

72. Sewage pollution in the metropolitan area near New York City and its effect on

inland water resources, by M. O. Leighton. 1902. 75 pp., 8 pis. 

79. Normal and polluted water in northeastern United States, by M. O. Leighton.

1903. 192 pp. 

103. A review of the laws forbidding pollution of inland waters in the United States,

by E. B. Goodell. 1904. 120pp. lOc. (See No. 152.)

108. Quality of water in the Susquehanna River drainage basin, by M. O. Leighton, 

with an introductory chapter on physiographic features, by G. B. Hollister.

1904. 76 pp., 4 pis. 

113. The disposal of strawboard and oil-well wastes, by R. L. Sackett and Isaiah

Bowman. 1905. 52 pp., 4 pis. 

121. Preliminary report on the pollution of Lake Champlain, by M. O. Leighton.

1905. 119pp., 13 pis. 

144. The normal distribution of chlorine in the natural waters of New York and New

England, by D. D. Jackson. 1905. 31 pp., 5 pis. 

152. A review of the laws forbidding pollution of inland waters in the United States

(second edition), by E. B. Goodell. 1905. 149 pp. lOc. 

179. Prevention of stream pollution by distillery refuse, by Herman Stabler. 1906.

34 pp., 1 pi.

185. Investigations on the purification of Boston sewage, by C.-E. A. Winslow and 

E. B.Phelps. 1906. 163pp. 25c.

186. Stream pollution by acid-iron wastes, a report based on investigations made at

Shelby, Ohio, by Herman Stabler. 1906. 36 pp., 1 pi. 

189. The prevention of stream pollution by strawboard waste, by Earle B. Phelps.

1906. 29 pp., 2 pis.

192. The Potomac River basin geographic history; rainfall and stream flow; pollution, typhoid fever, and character of water; relation of soils and forest cover 

to quality and Quantity of surface water; effect of industrial wastes on fishes; 

by Bailey Willis, R. H. Bolster, H. N. Parker, W. W. Ashe, and M. C. Marsh.

1907. 364pp., 10 pis.

193. The quality of surface waters in Minnesota, by R. B. Dole and F. F. Wesbrook. 

1907. 171 pp., 7 pis.

194. Pollution of Illinois and Mississippi rivers by Chicago sewage; a digest of testimony in the case of the State of Missouri v. the State of Illinois and the Sanitary District of Chicago, by M. O. Leighton. 1907. 369 pp., 2 pis. 40c.

37

O