Physical and Chemical Characteristics J of Waste Water Discharge FRANK .j. C:OOGA4?i ~ N E. D B. P,IILLE1 Louisiana Il'ild Life and Fisheries Contmissioit arid Louisiana S t r e a m Control Coi~antinsiori, Baton Roicgr, Lo.
T h i s investigation w a b undertaken to establish the phj sical and chemical composition of the various efRuents in the waste stream o f a large, modern petroleum refinery. Special emphasis was placed on iinniediate and long term oxygen demand characteristics. Zmmedia te oxygen demand was balanced against the oxygen available in the cooling water to find out whether or not an oxygen residual would commonly be found. lIethods of satisfying the inimediate oxygen demand of two wastes are discussed in order to determine if it is possible to ensure the discharge of a composite waste with some residual oxygen and thus to diminish the effect of the w-aste o n the receiving stream,
T
HE chemical and physical cliaracteristics of the vai,ious effluents contributing to the pollution load encountered a t a petroleum refinery were st,udied so that methods could be devised to lessen this load. il standard sampling procedure was followed; and the flow from each unit or group of similsr units (Table I) was sampled. The nature of each individud sLreain was
TSBLE
Sample 1
2 3 4
5 6
7 8
I.
1)ESCRIPTION OF SEWERS ANI) DISCHARGE SYSTEMS
~A1II'I.E STATIONS
Sample Description lIot mater seirer Acid plant effluent Secondary outfall Oil separator
Primary outfall Effluent to acid ditch No continued use Sewage and poxver plant effluent
1 Present address, Kaiser Aluminum and Chemical Corp., Baton Rouge, La.
All the water used for cooling, some sanitary sewagc, alid t b ~ o m runoff are collected in a hot water sewer as shown in Figllrci 1. Thii,tcwi separate units or groups oi units contribute to t h ~ : wntral t r u n k of this system. This flow enipties into it settling iition hasinj then into the river through two outfalls. . o u t i d 1 flow cont,rol consists of a. weir, the height of \riiic,h is reguliitcd 1)y removal planks set in slots, Thc sncund:ti'y o u t f d l control structure consists of three 18-incZ1 ciiamr:ttai. pipes. with gate valves on the pond side. Therc is alw :I large oil retaining h f f l ~ l eplaced in front of these three piyen, nstoiitliiiy :3 feot below the pond surface. 91
not, thoroughly checkcd. I t seemed nioIe important to determine the characteristics of the main n:tste streams and to know the important pollutional characteristics of the composiic waste, and thus to facilittite the investigation of the individual sources of pollution. Emphasis was placed on investigation of' the B.O.D. and immediate oxygen demsnd versus available oxygen relationship, hecause bioassays of the effluents, by mother departmental group, revealed them to be nontoxic. Tastes and odors vr-ere not a problem as the receiving stream \ m s somctimes salty and was tiot used a s R potable water source. The high temperatures oC the river water in the immediate vicinity of the outfall could constitute a barrier t o fish movement,; biologists of the Louisiana mild Life and Fisheries Commission will study this in a separate investigation. Each effluent stream was investigated for one or more of the following: flow rate, temperature, pH biological oxygen demand (B.O.D.), oxygen demand (O.D.), immediate oxygen demand, phenols, chlorides, ether
290
solubles, :tlkaliiiities, sulfides, sulfuric acid content, and YuIfti~, dioxide, depending upon the individual sample. With t-his information, various balances were obtained as shown in Table 11. Further investigation should include the use of process f i o ~ diagram in a comprehensive Rearch for methods So reducc t h p immediate and biochemical unit oxygen cleinands of all wast,cs i n order t o cut the loncl of the composite waste to a minimum.
Figure 1.
Hot W-ater Sewer
I N D U S T R I A L A N D E N G I N E E R I N G CHEMISTRY
Figure 2.
Oil Sewer Vol. 46, No. 2
-Petroleum TABLE: 11.
PHYSICAL AND
CHEMICAL
CH.4RBCTERISTICS OF
Wastes-
VARIOUS IVASTE STREAMS
(Sample numbers refer t o sample stations as shown in Table I )
Date 6/29/50 6/29/51 6/29/50 8/2/50
s/z/po
8/2/50 8 12/50 8 (2 '50 n / 2 1/ 5 1
212 1/51 2/21/51 2/21 / 5 l 2/21/51 2/21/51 3/7/21 3/7,21 1/7/51 3/7/51 3/7/51 3/7/51 3 / 7 '21
Sample N0.O
D.O., P.P.M
Temp
C.
P
BOD P;P:M..'
3 (15)O 5 (18)Q 7 (20)O
42 43 32
2.0 6.7 6.2
0.0 0.0 8.2
18.5 21.5 6.9
1 (16)'' 3 (15)C 4 (148)5 (18): 6 (19)
43 42 37 42 37
7.6 4.4 10.0 7.2 7.1
0.0 0.0 0.0 0.0 0.0
14.0 19.0 272.0 25.0 142.0
1 (16)a 2 (14)Q 3 (15). 4 (14a)a 5 (18)" 6 (19)a
28 23 26 26 2fi 30
7.8 "0 ? ,I 4 10.8 7.0 7.2
6.2 0.0 0.0 0.0 1.6 0.0
6.2 91 .o 16.4 317.0 7.9 133.0
1
31
9.6
5.76
31 27 30 24 26
4 : 0
0.0 0.0 0.0 6.9 6.4
13.3 148.0 17.0 0.2 2.0
.i .1
6.7 10.2 141 . O 14.0
2 3 4 5 7 (2Oj 8 (17)
, . .
9.8 7.8 6.7 7.3
4 .0 , . .
C.O.D., P.P.M.
...
... ...
... ..
. . ,
O.D.
P.F.ILi ... ..
... ...
...
. .
12.6 60.0 20.0 610.0 18.4 145.0
... ...
. . ,..
... ...
%
C.O.D. of
R.O.D.
Chlo Phenols, rides P.P.M. P.P.AI
Ether soiubles,
Alkalinities as CaC08
P.P.M OM
... ... ...
...
...
;
. .
k 280 65,100 2,703 50,136 1,310
14.0
...
16.3 300.0 14.4 11.0 8.5
48 000 2,981 29,041
...
con m o l d o 6 ...
,.
...
...
...
Flow, Gal./ RIin.
;
k', 760
. . ...
Neg. Neg!. Neg. reg.
...
... ...
Neg.
...
Neg. Neg.
1300
...
...
...
. .
... ...
...
... ... ... ... ...
0.0
...
... . .
POS.
. .
Pos. Pos.
1400 63 1480 26
. .
...
1830
..
1900
,..
Keg. Neg. Ne&
1920
f 1200 350
...
keb.
1570
,..
0.0
...
0:0
1650 1710
...
... ...
...
Keg,
...
... ...
...
... ,.. ... ...
0.0
12.0 0.0
...
0.0
...
0.0 94.0 0.0
...
. . . . . . . . ...
. . . . . . 0.0
37.3
0.0 1026 0.0
0.0 0.0 28.0
0.0
47.0
. . . . . . . . . . . . ...
.
,
..
..
, . .
..
...
.. ,.
0.0 2 i . o 112.0 0.0 0.0 51.4
...
..
.. ...
.. ... I . .
0.0
2a:o
4 ,7 0.0 94.0 0.0
3.7 0.0 112 0.0
0.0 28.0 0.0 61.4
0.0
0.0
37.3
0.0 0.0 112 0.0 0.0
28.0 27.9 0.0 25.0 23.3
...
,..
...
Refinery :3/8/51 3/8/51 33/8/21
3/8/a1 3/8/51 3/8/B 1
1
3 4 5 6
8 (17)
29 28 27 27 32 26
8.7 9.8 7.7 7.3 7.1
0.2 0.0 0.0 0.0 6.2
6.4
1.7
4/3/61 4/3/51, 4/3/51 4/3/51 4/3/61
1 3
7.2 6.4 9.2 6.8 6.8
5.3 0.0 0.0 0.5 6.0
7.1 10.4 272.0 17.3 Neg.
.4/25/51 4/25/51 4/26/51 4/25/51
1 34 7.4 3 32 7.0 4 28 10.0 5 33 7.9 All units operating
4.4 0.0 0.0 0.0
5,2 6.9 264.0 7.1
~4/26/5l 4/26/51 4/26/51 4/26/51 4/26/51
2 3 4
34 34 34 28 5 32 All units operating
7.3 3.0 5.8 9.5 7.0
4.2 0.0 0.0 0.0 0.0
3.2 123.0 4.0 144.0 8.1
Refinery 1 2 3 4
8.0 4.0
4.5 0.0
55.0 94.0
5/5/51 5/8/51 :>/S/?l .5/8/01 5/8/51 .5/9/51 2/9/51 0/9/5l 3/9/51 5/9/51
29 27 24 5 27 8 22 All units operating
,..
4
1
3i
io+
38 7.6 All units operating
5
1
2 d
4
41 34
2/3 1/51 < /31/51 7/3 1/5 1 7/31/51 7/31/51
2 3 4 5
0 0.0
8/1/51 8/1/51 8/1/51 8/1/51 8/1/51
2 3 4
...
5
1
1
5
1 2 3
0.0 0.0
.s
32 10+ 38 7 0 All units operating
3 4
...
4.24 0.0
8.4 2+
. . . . .
5
5/16/51 5/16/51 5/16/51
8/13/51 8/13/51 8/13/51 8/31/51 8/31/51
40 33
43 43
8.4 3.0
, . .
... , ,
. .
, , .
.
,
...
.. , . .
...
46
... , . .
120
...
56
, . I
64.0
... ...
368: 0 10.7
70.0 0.8
5.2 77.0
61.4
3h8:O 16.0
...
43
'7.'3
0.0
44 43 43 39 43
7.8 3.0 6.6 9.5 7.8
2.64 0.0 0.0
7.8 3.0 7.9
4.8
0.0
0.0
162,000 129,000 3,145 23,350
12.8 235.0 14.6 310.0 16.4
149,000 6,500 79,100 3,810 64,350
... , . I
. . ..
I
.
...
9.8
010
6.2 156.0 10.9 660.0 13.0
0.0 66.0 0.0 60.0 0.0
,.
...
..
... ...
...
... , . I
0.0
Pos.
I
.
.
...
Nep. Neg. Neg. Neg.
...
...
475 700 740 632 434
545 25
0.0 0.0 37.3 0.0 0.0
...
, . .
...
... ..
,..
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...
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...
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)
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...
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...
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Not flowing5 9 . ... 5.2
...
...
...
.., ..,
, . .
...
, . .
, . .
0.0 51000 24.0 Not flowing Washing out 166,400 0.0
...
... ...
...
...
... , . .
,..
36.0 0.0 9.1 0.0
... . . ...
0.0
...
...
..
...
(
, . .
... ... ... ... ... ).. , . .
...
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... .. ...
I
.
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...
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01027
.
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57.5 ... ... 0.0 .., 16.5 ... ... 11.7 ... ... separator. 6 Average flow taken a t .
...
.,
..
.
...
... ...
... . .
, . .
.
...
...
...
...
(
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...
6;OOO 41,140 4,000 80,100
. ,
...
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.
...
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...
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i9io
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38.9
... ... ...
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97.5
..
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.
... ...
17.4
,..
...
The other main system designated as the oil sewer is shown in Figure 2. All water that comes in contact with any hydrocarbon, in separators or otherwise, and all water used for caustic or acid wash with floor washings and normal runoff from around each unit flows through this oil sewer. An API separator receives this effluent and removes the oil from the water phase whereupon the
February 1954
...
6,5006 6 9 ' Not flowing 3,454 23 104,950 9.3
15.7 0.0 , . . 67.7 39.0 5'000 17.0 0.0 ... 47:400 430.0 71 .O ... 9 ~ 6 n n 2,665 26.6 3.1 8 . 4 Unk'nown ... 99,000 t o sampling stationa as shown in Figure 1; 14A is a t oil
o n
,..
... ... ..
2.6
0.0 18.4
...
16.0 16.7 475.0 23.4
;
.. .. ...
iiS:o
6.6 78.0
...
72 000 3,674 42,390 9,500
1600
0.0 0.0
. . ,
6;iooa 79 Not flowing 2,764 32 115,230 16
2.84 0.0
I . .
14.4 18.1 332.0 19.3 12.6
...
...
90.0 0.5
...
8.3
48;OOO 2,981 29,041 1,400 9,760
... .., ..
53.0 9.6
,..
14.0 13.1 300.0 13.0
...
0.0 0.0
..
45 44 45 4 41 5 45 Numbers in parentheses refer
. .
, . .
...
...
0:ois
... . .
o:o4o
. . . . . . . . . .
previous date.
oil is pumped back for rerun, and the water enters the settling pond as shown in Figure 2. Oil and water emulsions are broken by use of a commercial de-emulsifier or soda ash, and the mix is returned through the separator to facilitate oil recovery. The sludge is presently burned in pits located on the opposite side of the settling pond
INDUSTRIAL AND ENGINEERING CHEMISTRY
291
from the separator but in the near future will be put through vacuum filters t o recover all the oil possible. Surface drainage flows in open ditches; these drains go either directly into the settling pond or to a canal which empties into the settling pond. The acid plant effluent enters the settling pond a t point 14 in Figure 1. Therefore three streams enter the pond-the hot water sen-er, the oil separator effluent, and the acid plant effluent. There are two outlets from the pond into the river as s h o w in Figure 3. The acid plant effluent empties into the pond adjacent to the secondary outfall, and almost all the acid plant effluent discharges through this outfall. Most of the oil separator effluent goes out through the primary outfall.
Material balances were matie o n the immediate oxygen demiand loads of the main streams entering the settling pond ant1 the available dissolved oxygen from the hot water sewer. Gsing observed Ao.ivs as the basis for calculating dilution ratios, the settling pond dilutions were duplicatecl in tlic Itthoratory and the results agreed with those ohtained in the settling ponds. The effects of the total effluent, upon the condition of t,be receiving stream were obtained by means of biological oxygen demand (I3.O.D.) and dissolved oxygen (D.O.) profiles nt high a,nd low t,ides and at low stream stage*. RESULTS
The waste leaving the hot water sewer is an effluent resulting from use of once-through cooling and condenser water. This cooling water is pumped t>hrouglivarious units within the refinery ivithout hydrocarbon contact except for leakage. Homet,imcs a braclush stream is t h e source of refiner)- cooling and process xmter so chlorination of t'he intake water is necessary to keep marine groivth t,o a minimum.
I S RIVER
Figure 3.
Outfall System
The discharges from the primary and secondary outfalls are brought together as shoivn in Figure 3 a n d are channeled parallel to the river for 300 feet. This is done to allow addit,ional cooling time to prevent an increase in water temperature in the barge loading area. This also tends to prevent t,lie re-use of this water in the refinery. SA\II'LING
d
1
AND TESTING PROCEDURES
Oil separator B.O.D./day, pounds Acid plant B.O.D./day, pounds Available D.O. from hot watersewer, pounds D.O. a t primary outfall, pounds Immediate oxygen demand, pounds Primary outfall load, pounds Secondary outfall load, pounds Total load pounds B.O.D. sat'isfied per day Secondary outfallpounds/day pounds/day Primary outfall, Total, pounds/day
ACiD PLANT EFFLUENT
30
m
On the spot analyses for pH, tempcrature, and dissolved oxygen were run; a flow rate was determined and a lab sample was taken a t each point shown. The samples were placed under refrigeration and returned to the laboratory for the determination of one or more characteristics. B.O.D. and immediate oxygen demand determinations were run on these main streams to find out the reaction rates of t'he various effluents and combinations of effluents. Semilog plots of B.O.D. residual versus time (Figure 4) were made to show oxygen depletion characteristics as were B.O.D. versus time plots (Figure 5 ) to determine the immediate oxygen denlands that were exert,ed during the first 6 hours of t,he tests.
292
40
0
2 3 4 TIME (DAYS)
5
6
Figure 4. Semilog Plots of B.O.D. Residual os. Time
The p H of the hot water s c w e ~effluent varies from 7.2, the lowest reported, to 9.6, the highest. The dissolved oxygen in this effluent decreases steadily from a niaximuni during the winter months to a minimum during July and August. There is a corresponding increase in hot water effluent, flow during the summcr time, but this increase is not sufficient to maintain the sarnc available dissolved oxygen as shown in the oxygen balances. The
1,080 6,000 .j,460 5,860 Unknown
11,080 5,700 7,280
8,300 5,700 8,100
6,360 8,8JO 7,360
0 4,462 13,275
0 7,280 S.790 8.990
0
9,230 1,090 10,700
0 11 ,180 6,260 3,800
,..
17,780
12,690
10,050
2,960 2,900 8,860
3,520 656 4,176
1,220 2,OfiO 3,280
13,820 4,060 8.600
12,760 ,340 5,660
12,200
0 Unknown
0 8,000 13,500 0 . 0 not flow-
0 8,820 22,150 0 . 0 not flow-
10,300 3,760 8,575
5,300 5,700 6,320
5,050 5,700 4,680
31,700 9,350 3,800
983 8,744 4,780 12,820
0 5,605 3,900 7,650
0 5.543 4,880 5,860
G,2%
13,410 5,780
3,728 31,600 9,630
17,570
13,630
10.7SO
18,780
41,250
4,226 1,570 5,795
2,540 1,950 4,400
1,940 1,610 3,550
4,430 1,738 6,188
9,020 3,240 12,260
,
ing
. ..
ing
0 . 0 not flowing
...
...
.,
4,'kO
7,'300
i,i75
I N D U S T R I A L A N D E N G I N E E R I N G CHEMISTRY
Vol. 46, No. 2:
P e t r o l e u m WastesA N D BIOCHEMICAL OXYGENDEMANDS EXERTED BY THE ACID EFFLUEXT; SEPARATOR EFFLUEXT, TABLE IVA. CHEMICAL HOT plTATER SEWER, AND PRIMARY AXD SECOXD.4RY OUTFALLS
Sample Temp., by Vol., Time C. % Hour; 25 25 25 25 25 25 25 21 21 21 21 21 21 21 21 21 21 21 21 21 21 21 21 21
33 33 33 33 33 33 33 33 25 25
25 25 25 25 25 21
8.33 8.33 8.33 8.33 8.33 8.33 8.33 8.33 8.33 8.33 8.33 8.33 3.33 3.33 3.33 8.33 8.33 8.33 8.33 8.33 8.33 8.33 8.33 8.33 8.33 8.33 8.33 8.33 8.33 8.33 8.33 8.33
lii4
I/?
1
2 4 6 8 12 16 20 24 48 72 96 120
1/4
1 2 4 24 48 72 96 120
:$4
C.O.D. C.O.D. R ~ u c and after tion upon B.O.D., Aeration, Aeration, P.P.lLi. P.P.31. P.P.M. (Min.) % Initial D 0.
final D.O.,
Acid Effluent 5/9/51 8.18 3.07 8.18 3.10 8.18 3.07 8.18 2.80 8.18 3.09 8.18 2.95 8.08 2.90 2.90 8.18 2.90 8.18 2.90 8.18 8.18 2.87 3.00 8.18 5.95 8.18 5.85 8.18 8.18 4.95 Secondary 8/1/51 8.90 8.90 8.90 8.90 8.90 8.90 8.90 8.90 8.50 8.30 8.50 7.88 2.90 8.45 8.38 ( 3 2 8.46 7.43
,
... ... .., ...
. o
... ... ... ... ... ...
%
3.33 3.33 8.33 8.33 8.33 8.33 8.33 8.33 8.33 8.33 8.33 8.33 3.33 3.33 1.66 1.66 0.33
...
...
...
... ... , , .
..
, . .
Separator Effluent 4/25/jl 4.04 0.20 46.0 4.04 0.16 46.6 2 4.04 0.0 ,.. 4 4.04 0.0 , . , 6 4.04 0.0 ,.
...
... ... , , . ...
.
Separator Effluent 4/26/51 1/4 8.12 3.48 55.8; 1/4 7.95 6.17 55.8 '/? 8.12 3.45 56.0C
35.5 21.4 35.4
Separator Effluent 5/8/51 8.18 2.35 70.0
3.33 3.33 3.33 3.33 3.33 3.33 3.33
26 21
...
0.0 0.0 0.0 0.0 2.4 7.5 6.7 10.3 10.9
Separator Effluent ;/9/51 8.18 4.26 118.0 1; 4 8.08 4 22 110.0 8.08 4.14 118.2 8.08 3.60 2 134.0 8.08 2 75 4 160.0 8.08 6 2.85 157.0 8.08 2.38 12 171 .O
.
...
61.0 61 . O 61 .O 65.0 67.0 70.0 94.0
Sample Initial by Vol., Time, D.O.,
3.33 3.33 3.33 3.33 3.33 1.66 1.66
I . .
61.0
1/14
c.
...
61.4 61.0 61.4 64.5 61.1 62.7 61 .O
8.33
Temp
36 4 61.6 36 8
,..
, . . , . .
'/;
..,
... . .
...
.. , .
26 21 21 21 21 21
8.33 8.33 8.33 8.33 8.33 8.33
Hours P.P.M.
Final D.O.,
P.P.M.
Separator Effluent 5/9/51 8.08 2.93 16 3.05 20 8.08 2.10 24 8.08 1.46 8.08 48 8.08 0.11 72 3.13 8.08 96 8.08 1.95 120
C.O.D. C.O.D. Reducand after tion upon B.O.D., Aeration, Aeration, P.P.M. (Min.) % (Contd.)
155.0 151 .O 180.0 199 I O 236.0 297.0 368.0
Separator Effluent 5/16/51 53.0 1 7.95 6.20 5.50 54.0 24 7.30
...
...
... ... ...
...
... ...
... ...
H o t Water Sewer Effluent 10/2/51 0.0 8.75 8.75 1/4 1 3 4 6 24 48 72 96 120 48 72 96 120 120
8.70 8.70 8.60 8.60 8.60 8.57 7.90 8.05 7.98 7.50 6.72 6.30 6.25 6.25
8.70 8.70 8.45 8.33 8.20 8.27 7.48 7.15 6.80 5.62 5.00 5.10 4.88 5.96
0.0 0.0 1.8 3.2 4.8 6.0 6.2 8.4 13.2 56.0 52.0 72.0 83.0 90.0
Primary EWuent 5/16/51 0.5 7.50 1 7.54 4.4 6.93 7.30 24 1 4.0 48 7.50 6.35 9.0 5.98 6.72 72 9.6 96 5.50 6.30 8.5 5.55 6.25 120
Primary Effluent 8/1/51 8.33 8.90 0.0 ... 8.33 2 8.90 8.90 0.0 . . 8.33 4 8.65 8.60 0.6 .., 8.33 8 8.65 8.40 3.0 ... 8.33 8.04 L64 ... 24 8.50 8.33 7.95 6.60 ... 48 8.50 8.33 7.78 8.04 ... 72 8.48 8.33 7.67 8.50 ... 96 8.38 8.33 120 8.46 7.37 13.0 ... 8.33 (1 Moderate aeration 15 min., 3 5 . 5 C.O.D. 3 6 . 4 % reduction. Heavy 15 min.,,21.4-C.O.D., 61.6% reduotion. 0 Moderate 15 min., 30.4 C.O.D., 3 6 . 8 % reductlon. 21
. . ,..
...
... ... . . ... ..
... ...
from 130 p.p.m. to 150 p.p.m. Phenols were run on this effluent amounts of dissolved oxygen have been determined in the samples and were found t,o be present, but since phenols could not be taken on several days during the 7 months, February through detected in the secondary outfall, sampling of this waste was August 1951. One day in February 8575 pounds per day of oxydiscontinued. gen mas available and one day in August only 3728 pounds per The acid plant effluent entering the pond is water containing day was available. -4pproximately 115,000 gallons per minute dissolved sulfur dioxide gas from scrubbers and cooling towers was the total flow in February and 150,000 gallons per minute was the observed flow in rlugust on the dates of sampling. This represents a decrease of 56% in TABLE IVB. CHEMICAL 4ND OXYGEN D E ~ I A K RESUXE D AT 30" c., '/4 HR. the available dissolved oxygen with a corresponding increase ReducTime, C.Q.D. tion in flow of approximately 20% of alter upon Sample by volume (Table 111). The by Initial Final AerAerAerD.O.. C.O.D., ation, ation, ation, Date Description Tznip., Vol., Time, D.O., hot water sewer effluent hm a 1951 of Sample c. % Hours P.P.31. P.F.M. P.P.M. Min. P.P.M. c/o low B.O.D., average 6 p.p.m. 8/28 ot watersewer 30 8.33 */4 8.40 8.40 0.0 .. ... ... (Figuresgand 10). The pounds 8/28 Zcid effluent 30 3.33 I/, 8.72 7 42 39.0 .. ., .. .. ... 8/28 (3) Secondary 30 8.33 l/4 8.40 8.40 0.0 .. ... per day B.O.D. of t8his efflu8/28 (4) Separator effluent 30 3.33 l/g 8.72 6.37 71.0 .. ,.. ent is large because of the large 8/28 Primary 30 8.33 '/P 8.40 8.14 3.1 .. . . . 9..6....2. 8/29 2) A e r a t e d f o r l 5 m i n . 30 3.33 '/a 8.50 8.45 ,,, 15 1.5 volume of the stream. There 8/29 4) Separator effluent 30 3.33 I/+ 8.50 7.50 ... 15 30.0 57.7 aerated for 15 niin. is noimmediatedemand exerted (2 & 4 ) A c i d a n d s e p a 30 6.66 I/' 8.25 6.55 ... 15 25.0 0.2 8/29 rator mixture by this effluent (Table 117). 8/29 (2 & 4) Acidandsepa30 6.66 8.25 7.42 . . . 15 13.45 31.4 An effluent running into the rator mixture aerated prior to mixing acid plant discharge ditch bel/4 8.50 8.25 ... 15 7.5 80.8 8/29 (2) Acid effluent aer30 3.33 fore it reached the pond was ated for 15 min. 8/29 (4) Separator effluent 30 3.33 1/4 8.50 7.30 . . . 15 36.0 49.4 sampled on several occasions. aerated for 15 min. The flow was found t,o be ap8/29 (2 & 4) Acidandsepa30 6.66 1/1 8.30 7.00 .., 15 19.5 23.5 rator mixture aerproximately 1300 gallons per ated prior to mixing minute, with a B.O.D. ranging
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February 1954
INDUSTRIAL AND ENGINEERING CHEMISTRY
293
and from leakage TIME (DAYS) from the units 1 2 3 4 5 I I I I I within t h e acid p l a n t . A pH of less than 3 is characteristic of t h i s effluent. This w a st e a v e r a g es 5 0 0 0 g a l l o n s per minute and exerts ACID PLANT a definite imino diate oxygen demand. A 120 m a x i m u m t o 18 R0.D CURVE p.p.m. m i n i m u m represents the range for this demand (average 60 0 p.p.m.). The peiI 2 3 4 6 8 10 12 14 16 18 2022 2 4 2 6 2 8 TIME LHDURS) centage of sulfuric acid present in the Figure 5 . H.O.D. CY. Time Plots effluent ranges from 0.027 to a maximum of 0.098. Analysis of all samples of this effluent shoivctl that the immediate oxygen demand in pounds per day \v:is approximately 1 0 0 ~ higher o than that of the oil separator \wet?. This demand is caused primarily by the conversion oT sulfur dioxide t,o sulfur trioxide. As can lie seen from the plot of 13.0.11. residual (p.p.m.j versus time (da Figure 4, the imniediati~ oxygen demand is approximately 80% of the 5-day H.O.D. &lftc>r t'he first day, the rate of reaction, K, equals 0.107, its shown I>\Figure 4. The immediate oxygen demand of this wid \rast(I varied between a maximum of 97.5% and a nlinirnum 24% of thr. &day B.O.D. After the immediate osygen demalid in wtisfictl. a leveling off occurs as seen in Figure 4 90 that a slop(%of ZIWI is evident. I n the first and second day the slope T ~ : I S 0.144, t,Iw slope for the second to the third day ww 0.Oi:J. This change in slope was probably caused by thr. dying of bacteria tluc to thc tosic, effects of the effluent, n i t h a multiplicntion of r following a depletion of the total hacteria populatioti. Tho most important characteristic of this :tciti cffluc~ntis the high ininic~diatc~ oxygen demand ttserted.
2ot
TABLEv,
IMMEDIATE ~ E M A X D REDCCTIOSS OS SEPARATOR 1v.4sTER -~llc:drictionl (:ai0 (1)
Aeration separately Aeration separately and mixirig afterwards Mixture only Mixture and then aeiatiori of this mixture
ii 4
73 .0
?" 1 .>o2
.\(:ID
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. but, t,hey were also prcsent a t refinery €3. Of Solids from the effiuenx of these three refineries, one hail primarily emulsion and no significant amount of biological growth, ii second had principally filamentous blue-green algnc, which were not part,icularly objectionrtble, and the third h:td primarily slime bacteria, which wcrc the most troublesome. AI1 slime growths contained some free arid erriu~sifiedo i l and silt. Other organisms were generally of minor significance. Planki-on studies of raw or influent water t,o t.he plant were not made, a,s the troublesome organisms were prirnrtrily bncterial in nature. The usual plankton procedures do not include hacterial studies. X1P
I N D U S T R I A L A N D E N G I N E E R I N G CHEMISTRY
Vol. 46
