Industrial Wastes
0 . 0
PULP AND
INDUSTRY L. F. WARRICK
Wisconsin Board of Health, Madison, Wis
b b T h e pulp and paper industry has increasingly given attention to means for taking care of problems occasioned by its wastes. A brief historical &sum4 shows the trend from individual mill studies through state or regional programs to the more recent country-wide activities of t h e industry to reduce, utilize, or treat wastes in order to m i n h i s e water pollution. Mitl effluents are broadly classed as chemical pulping wastes or white-water (fiber) wastes. The characteristics of each are described with particular regard to effects on t h e waterways in which they are disoharged. T h e pmcedures for bringing about stream improvement in general c o m e under t h e headings of utili-
zation, and of treatment and disposal. Save-all and recirculation systems for white-water wastes am described. Savings effected by utilhation of white water more than justify the costs of extensive r e c o v q systems. Reduetions in losses of papermaking stock to the streams through mill improvements are cited. Chemical pulping wastes, such as sulfite waste liquor, are t h e stmngest from a pollution point of view, and are t h e most d i 5 c u l t to utilize or treat and dispose of in a practical and emnomical manner. In general, the costs for taking care of wastes to prevent serious stream pollution am increasingly to be recognized as an essential part of production costs.
c
example, the Wisconsin sulfite pulp manufacturers agreed in 1939 t o support joint research by a special staff on ways and means for further reducing pollution by sulfite waste liquor. An allotment of 10 cents per ton of pulp produced was d e to c a r y out essential studies. These included laboratory experiments on most promising methods a t The InstituF of Paper Chemistry, followed by pilot plant tests and other activities in the 6. A similar agreement was entered into by the Wisconsin Kraft Pulp Manufacturers about the same time; developments were financed jointly by the state group until the waste dispposal activities were recently incorporated into the ihdustry-wide program of the Na. tional Council for Stream Improvement of the Pulp, Paper and Paperboard Industries; Inc., This organization started in 1944 to carry on research and development work in the various pulp and papermaking etstes, with regional advisory committees to sdd in estabbhing an& carrying out activities;. There is. already evidence to show khat programs adopted by these various agencies me producing results’of value in cleaning up our lakes and streams.
LEAN water is needed by many industries. Especially for the pulp and paper industry, an adequate wster supply of suitable quality is a primary factor in manufacturing processes. Water is essential in most of the steps in producing pulp and ps, per. It is employed for power and steam production in.tbe mills. Vacuum evaporatom use water and also cooling and condensing equipment. Accordingly, the existence of a sufficient supply of water, wailable at little cost for conditioning to render it satisfactory for mill use, is a defmite asset. The use of large amounts of water in pulp, paper, and paperboard production has inevitably created problem of waste & pas+l.. Substance d d e d to the water and discharged to water courses in mill effluents occa%on varying degrees of pollution, the nature of which will be mentioned later. Erronomy in production requires that lOss ofpapermsking materials be kept at a ininimum, and needs for stre- improvement neoe&tate that certain other ingredients of the effluentsbe removed and utilized or disposed of by the most effective,practical methods. The pulp and paper industry has increasingly given attention to jindiugways v d w m for taking care of the problem occwioned by its wastes. Initidly most of,the progreb in reducing wastes was made through rese,arch and development conducted by indihdual mills or coiporations. Early attention was directed to devising and installing systems for reclaiming fiber and other mterials used in the products being discharged through mill sew; ers and charged off as “sewer losses”, Surveys often revealed high losses which could Be corrected at the source or reduced by applying certain technological principles to waste recovery. These developments generally have shown profits on the investment required for talla at ion and operation of tbe systems. The more difficult pmblem of what could be done with the wastes from chedcal &nufacture of pulp, such as sulfite waste liquor, remained unsolved. 4lthougbmuch money was spent on individual mill studies, the progresa was slow. The answer to what oould he done with these pulping wastes was, however, of major importance from the point of view of stream improvement. Industrial groups are increasingly seeing the advantages of collective action in solving mme of their common waste utilizs, tion or treatment and disposal problems. The need for concerted effort has been recognized by the pulp and paper industry. For I
.
,
GENERALPROBLEM
. .
The general problem confronting the industry is what can be done to return waters.used in their processes to the stream in as nearly the .same condition as it was originaUy: Practical and economic consideratious mitigate agsjast the ideal solution, however, and the question resolves itself into how far it is feasible and necessary to go in waste reduction measures to redore watem to reasonably clean conditions. The h a l utilization of watem receiving mill effluentg have a definite hearing on the.degree of. cleanliness that should be attained. Consideration should be given to the uses of these waters far drinking and domestic purposes, industrial water supply, watering of stock, propagation of 6sh, oysters, and other aquatic life, navigation, power production, agricultural development involving,irrigation, and recreatiod pwposes, such as bathing, boating, and fishing. Estheticconsid-. erations are involved, particularly in recreational areas. fibrous wastes, when discharged into a stream, have been found to collect on the. bottom in the form of large sludge deposits. This sludge mat covem the bottomof the stream in Such a yay 88 to interfere with the spawn and spawnhg of &h. It also entraps 620
May 1947
Figure 1.
miti
671
INDUSTRIAL AND ENGINEERING CHEMISTRY
Sulfite Vaste Storage Pond ant1 Cascade ieration. to Redrice O\?gen Deniancl i n the Stream
cnrries t l o ~ i with i it other orgariic matter n-liich decomposes
arid oftcn give< ri-e t o offensive conditions. Particularly is thi,
true duriiig t h e summer months when large portion5 of the sludge are carried t o the surface by gas bubhlei formed iii the decomposition of the organic matter. Uiologic:il studies have shown t h a t pulp mill wiGtes are detrinient:il t o fi-li and other aquatic life because of their high oxygen ticniand, their fibrous sludge producing solids, and, in some inst:rnres, their toxic components. T h e oxidation of spent chemicals and the lignin, carhohytlrates, :%rid other materials estracted from tlie v o o d iii the cliemical pulping processe; brings about a marlied reduction in the dissolved oxygen in a stream when tlic-c sulwtniices are discharged into it. If the dissolved oxygen coiiteiit of the miter is depleted, odors mid other iiuiiaiice conditions c a n I F espected, nnd if it iF reduced below 2 parts per million, tliere \vi11 hr iiisuficieiit oxygen t o support moqt fish life. The f i ~ hmubt either Feel; otlier habitat or suffoc:ite through lack of diwolved oxygcii. The folloxiiig sequence of pollution effects resulted in a situafnctor in the initiation of a state-n-ide st'ream sanitation program in Jl-iscoiisiii ( 2 ) : Floating fiber, chips, and decompobing Llttdge accumulated above one of several dams downstream from a sulfite pulp and paper mill. Great numbers of fish died in the btrenni belov- the same d a m as a result of osygen depletioii, due principally t o sulfite pulping wastes. -\s a result of an iiive-tigntion, stream conditions x e r e improved through the area n-here the fish died by t h e installation of efficient devices for reducing fiber losses and sludge producing m s t e s , and by providing a .storage poiid for the sulfite pulping waste having a cascade spilln-ay (Figure 1) for aeration of the waates t o decrease their rapid absorption of dissolved oxygen from the stream. -1reservoir t o increase the dry weather flow of the river helped further n.ith stream improvement. STREAXI AER.4TION
3Icclintiical itrenni aeration facilities 1ial.e been tried experinieiitally, stxrtiiig in 1943, t o offset t h e effects of greater pollution loading with increased production of sulfite pulp. l i r is 11lon.n through porous tubes aiid plates submerged in t h e stream a h v e the r:rcl;s and in the tailrace a t a poiver plant ahout tnelve miles lielox the mill, t o rcstore some of the dissolved osygeii and reduce the oq-geii demand in the stream. Beneficial results have been described in receiit puhlications and n-ill not be repeated here (9). 1Iechaiiical stream aeration may be regarded only as a n ameliorating meamre, pending development of acceptable means for abating pollution a t its source. K h e r e applicahle, however, it
offers n n-ay of ,supplemeiiting otlier metliods for avoiding tiwrilile due t o osygeii depletion Tvith prolonged lon- strram flo~vs.nccidental q)ills of n x i t e , and other emergency coi~ditionu. Before proceeding further with remedial measures in stream improvement, n-e \Till consider the processes producing pollutioiial n-a-tes. For this discussion the mill effluents are brondly ed a+ chemical pulping Ti-astes and as .ivliite-water (fiber) n-nates. The former include essentially spent c hemicals along nitti the riorifihrouu ingredients removed in the pulping processes; the latter contain a n-ide variety of papermaking materials in addition t o fiber, in large part cnrried in suspeiision in the water. CHEXIICAL PULPING W A S T E S
SL-LFITE (.&CID) PROCESS. The sulfite process for pulping viood involves "cooking" chips in a digester at high temperatures and pressures along xvitli a solution of sulfurous acid in which lime or some other base is dissolved. T h e cellulose fibers are separated from lignin, hemicelluloses, and other cementing materials. Calcium bisulfite in the cooking liquor reacts with the lignin in the n-ood to form soluble calcium lignosulfonate. Wood gums are :~lso hydrolyzed in the acid cooking liquor a t high temperatures. The soluble materials present in the spent liquor are drained atray from t,he fibers a t t h e end of t h e cook, the liquid effluent being k n o n n R S sulfite ivaste liquor. Soluble products of digestion in the sulfite waste liquor comprise about 50% of the TTeight of the wood. For every ton of !sulfite pulp, about a ton of soluble material is discharged t o streams in about 2500 gallons of \Taste liquor. Xormally i t contains 1 0 ~ o solids, mostly lignin and carbohydrates. The quantities vary according t o the Tvoods used and method of cook. Comporit,ioiis of waste liquors from sulfite pulping of spruce and poplar, 011a 10ccsolid tlasis, are as follows: Lignin Carbohydrates Proteins Resins and fats SO? combined with lignin CaO combined u i t h iignosulfonic acid
Total
Sprucs 4.6Y0 2.3 0.1 0,s 1.7 0 .8
Poplar
3 iCE 3 2 0.1
0 7 1 6 0 7
--_
10 0';
This tahulatioii sho~i-st h a t lignin, carhohydr:ttes, :iiid siilfiir dioxide combined Ivitli ligiiiii comprise the major constitueiits of tlie waste. These constituents are our primary concerii iii waste uti!izatioii, or treatnieiit and disposal, in effecting stre:im improvement. Procedures for the solution of t h e sulfite w i s t e problem have varied all the ~ ~ from x y measures n-hich noulti change the prin-
672
INDUSTRIAL AND ENGINEERING CHEMISTRY
Table I.
Type of Mill
Mill So.
Rewilts of 1916 Survey of Wastes at Wisconsin Pulp a n d Paper 31ills"
TI-aste, Gal. per Ton of Product
Solids, Lb. per Ton of Product Fixed Volatile sussueTotal pended pended soluble
____
36.8
Book
67.0
4 v . Loss Detd. b y hlill, %
0.9 1.0 1.3
...
0.7
... 0.6
...
Fiber Loss, % of Production 1946 1945
1 1 1.5 0 5 0 6
;
1.1 0 6 1 3 0 9
25.5 22.5
10
....
....
...
12 13 14
23,048
12 3 0.3 1: 8 r 3 2.9 0 0 4.4 3 7 5.7
... 26.2 16.5 6 2 24 1 51 0 63 3 27 6 37.1 20.6 30 4
43.9 65.5 21.3 132.4 355 4 32.1 59 2 88.: 222 113.4
1.3 0.8 0.3 1.2 2.5 3.2 1.4 1.9 1 0 1 5
28,432
6 8 28 4 18 4 10 9 12 4 3 4 57 3 5 7 17.9
11 5 72.1 60.9 26.9 ''9 1 17.5 30 9 12.1 31 2
.i5 6 117 7 71 2 5 , 117 3 44.5 649.4 93.2 146.8
33,52i 17,980 18,630 20,690
34.5 29.4 8 9 14.7
132 1 33.0 99.3 18.5
305 0 04.6 47 4 59.8
ii,iso
.
6.2 18.7
3'1 .ii 2
'35'4 108 6
0.5
11
AV. m-rapping
hv. Bond
27 2 31.3 66.9 20.8 37.2 29.0 65.7 44.6
-innua1
12 3 28 8
13,071 Tissue
28 29 30 31 32 33
,
__
,
2
...
0 8 1 8 1 8 2 4 3 0
... 1.0
... ...
2.3 1.2
0.8
...
0 3 ..,
...
1.5
0 6 3 6 3 0 1 3 1 1 0 9 1 5 0 6 1.6 6 6 1.6
... 1.2 ...
5 0
0.4
0'2 2.8
...
0.9
1\. .
20.461
34 35 36 .\v.
59,750 59,230
27,200 48,72i
1 0 11 3 3.7 5.3
13.8 49 0 34 2 32.2
88 4 118 1 12i.9 111.4
4 2 1.9
...
0 7 2.4 1.7 1.6
Board
37
5,600
0 9
10.9
26 3
0.6
0 5
Blark middinl:
38
57,400
13 2
86.3
232 9
4.2
..
Glasrine
Rag arid de-inkpd p u l p
R39 D40
58,500 25,055
I14 1 R42 D43
95,820 19,810 49.796
.i\.. K r a f t pulp
44 45 46 47 48 .\ v .
Sulfite pulp
49
50
51 52 53 54 55 56 57 58 59 60 61 62 63 AV. Groundwood pulp
64 65 66 67 68 AV.
Vol. 39, No. 5
720'
71,030
56,820 .57,630 52,420 86.290
64.836 51,500 45,600 4.360' 56,2iO 15,570 55.310 39,680 80,580 37,330 42,040 22,490 (1,340 54.690
75.900
38,290 50.470 so0
i;P&
6 ,550 5i0 2,302
109 8 29 6 97 5 198 4 352.5 157.6 18.3 43.5 10.9 91.6 3.9 33.6 14.4 4 8 0 2 2 4 3.9 2 1 0.8 4 0 2.6 1.3 0.9
1.2 11.c 1.B
1.5 3.7 0 3
..
0 0 21 0.03 0.15
...
109 8 104 8 453.2 126 4 147.0 188 2
197 2 289.5 581.0 3234 4 "55 9 !ill 6
77 3 8
400 0 826 6 270 201., 3G0.2 329 8
1 0 2 4 1.1
1434 !I
1.6
71 26 01 38 61
S 2 8 2
36 2 37 8 8 8 20.5 35 2 99.5 4.4 32 1 28.0 13 1 50.2 55.: :36,i 48 1 57.6 37.6 0.6
...
5.2 36.4 2 6 11.2
E
2057.5 2763 2 4059.jc 2041.5 2541 4 /6Q.0c 3686.2 2925.9 2293.4 2069 2845.t 1297.8' 2349.5 1956 6 2413.8 4.1
....
2
3 15., 4.6
7.0
... ...
...
i'i ...
... ... ...
0.4 2.2 13
...
1.4
4'0 3 7
i:i ...
...
... ...
0.1
0:l
...
0 8
3 4 1.4 1 2 0 8 1 1 2 0 3 5 2 0 4 0 0 '.I 2 0
0 5
I n
3 1 1.9 2 0 0 6 1 6 0.8 I 6 2.2 1 3 1.6 1 7 0 3 0.4 1.2
O.Q 4 6
3 2 2.9
Finanrial 1.0s. h ,
-_____
3,927 1,516 1,149 14,891 6,091 4,265 2,188 2.418 1,068
.,
,
, ,
?,027 0,003 21,200 5,113 19,403 13,146 1,756 8,161 5,861 1.363
..
,.
.
.
40
26 15 89 60 90 24 44 35 47
~ ~ iper l 1)ay. 1946 147 51 112 87 30 73 3 41 135 14 19 92 36 90 1 9 18 45 65
E:
5 1 05 18 6 8
388 64 127 101 54
9 80 101 60 51 41 17
06 128 47 113
19 31 52 66 06 77 20
28 112 198 45 78 17 90 16 73
29 78 61 0 2 213 84 89 41 6 38 54.37 20.96 29 40
. . . . . . . . .
10 125 127 19 66 38 41 13 56
5.745 7.196 4,671 4,367
171 108 173 32
67 61 86
133 06 63 96 51 00 7 3 60
2.358 5.3i5 22,631 3.267 957 5,740 1,432 1,593
..
2,834 5,279 36,909 8,212 1,197 2,428 2,765 1.455 l,i6R
4,088 2,270
10,606 994 2,405
6;305 ,, ,
,
,
2,902 1,212 1,802 ,,
., .
.,..
7,424 2,519 2,388 ,
.,
, ,
...
....
82
'37 116
14 37 38
28 82 67 59
22 206 100 109
29.02 1.5 2 % 19 29
11
31
32.37
7'80
...
....
0 8
1,780
4,975
4 3
5.3
19,487
12,236
158
190
135 8b
5 5
2 1
.5,042 5,405 7,110
4,312
469 308 450 527 260 403
308 524 660 439 244 435
127 0:i 28 i o 200 54
574 677 453 275 277 451
391 333 4.59 217 457 371
5 2
h 9
i.274
,.>6C --
162
6 1
8 4
3.9 ,'3 6 13 4 H 1 9 3.1
2 .3
14,407
1 7
60.680
1 5 3 1
;71,360 62,426
10,205 30,470 43,546 49,237
44,012
74,262
... ...
0 7 1 6 0.5 0.5 0.6 1.0 0.8 0.5
5-Day R.O.D. Population Equivalent Persone per s o . of pereons ton of product 1946 1945 1946 1945 13,074 11,589 39 37 32 45 6.019 8,195 21 19 3,227 2,378 38 30 540 417 62 66OC 20,947 212,520 17 30 1,209 1.807 44 14 3,690 1,100 41 .... 4,986 ..... 64 .... 5,618 .., . . 40 29
1.8 1.9 0 4 1.0
;.
6.002 17,615
1.6 2 0
2
1 1.
0 0 2c 1.6 1 4 0 6 2.5 2 8 1.8
0 4 1.0 0 3 3.6 1.1 1.9 1.0 0.6 4 9 2.5 2.1
2.0
1.8
I.8 ,I
z:; ;:: 003
0'.3 1.8 0.1
0.6
. . . . . . . . . .
. . . . . . . . . . 100,640 147,826 98,249 618251 478:860 427,615 66,315 198,045 404,035 206,741 344.390 365,091 148'00 330:;62 131,296 138
. . . .
....
1.1
132,192 148,824 145,431 27,5360 284:226 723,240 84,588 645,753 392,196 176,468 262,143 2i6'747 408:048 95,718
..........
.... 0.004 0 7 1.5
7,656 4.204 14,159
,,
.....
..,
.., . .
8 ..
ii
53 10 20
ij,?
:3fi ;iO
.... 3'3. l i i 1'29 07 6 2 , ti0
417 fib 120 i i i
.. 48 96 04 i o 4 29 40.14 113 40
1480 1'344 1054 2400 3666 3900 616ZC 3190 3040 2183 4092 7380 88SC 1200' 1630 0454 3326 3220 3463 3140 2926 2467 3316 , . . , 1214c 1781 2821 3747 2440 2206 2857 3309
. . . :i0 2,990 1,112
906 662 711
23
209 00
,5 ! l i i i 76 Cix 04 1 4 :i:i 117 07 122 :il 8 8 1:i 112 56 62 42
. . .
....
0 77
0 P 49 .54 ...
C
:i 70 3 xi 1 07
....
52
a Table prepared by Bureau of Sanitary Engineering, nisconsin Board of Health, as parr of annual mill waste survey. D a t a compiled by T . Y. TVisJiiea.ski from analyses made by Gerald, Lawton of composite samples covering a week o i operatipa, collected n i t h cooperarion of technirai personnel the rn~lls. b T h e financlal loss to the mlll through the loss of fiber was calculated using the follow~ng values a s a basis: Book wrapping, tlssue, and nulhte bond paper, $40 per t o n ' newsprint, $25;. paperboard, $20; rag content bonds,, %BO! sulfite and kraft pulp, $40; groundyood pulp, $15. These ralues are the same as those used
