EPA-330/9-74-001-d
NATIONAL FIELD INVESTIGATIONS CENTER
CINCINNATI
OPERATIONAL CONTROL PROCEDURES
for the
ACTIVATED SLUDGE PROCESS
APPENDIX
MARCH 1974
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
OFFICE OF ENFORCEMENT AND GENERAL COUNSEL
*V ?*£-
*
-------
EQUIVALENTS USED FOR ACTIVATED SLUDGE CALCULATIONS
ft
inches
m
m
sq ft
sq m
cu ft
cu ft
cu ft
cu m
cu m
cu m
gal
gal
liter
mgd
cu in/day
gpd/sq ft
cu m/day/sq m
Ib
Ib
kg
kg
lbs/1000 cu ft
g/cu m
cu ft (H20)
gal (H20)
liter (H20)
Ib/day
kg/day
Ib
kg
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
0.3048
2.540
3.28083
39.37
0.0929
10.7639
28.3170
0.028317
7.48052
1000.0
35.3145
264.179
3.785
0.003785
0.26417
3785
0.000264
0.0408
24.51
0.453592
453.592
2.20462
1000.0
16.0
0.0625
62.4
8.345
1.000
=
=
=
=
=
rs
=
=
=
=
=
=
=
=
£5
r5
=
=
m
cm
ft
in
sq m
sq ft
liter
cu m
gal
liter
cu ft
gal
liter
cu m
gal
cu m/day
mgd
cu m/day/sq m
gpd/sq ft
kg
g
Ib
g
g/cu m
lbs/1000 cu ft
Ib (H20)
Ib (H20)
kg (H20)
English SLU
Metric SLU
mgd x mg/1 x 8.345
cu m/day x mg/1 /1000
English SLU x (V7CR*/1198)
Metric SLU x (WCR/10)
Metric SLU x 264.2
English SLU x 0.003785
*WCR = sludge weight (mg/1)/centrifuged concentration (%)
-------
NATIONAL FIELD INVESTIGATIONS CENTER - CINCINNATI
OPERATIONAL CONTROL PROCEDURES
FOR THE
ACTIVATED SLUDGE PROCESS
APPENDIX
by
Alfred W. West, P.E.
Chief, Waste Treatment Branch
MARCH 1974
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
OFFICE OF ENFORCEMENT AND GENERAL COUNSEL
-------
FOREWORD
The Waste Treatment Branch of the National Field
Investigations Center - Cincinnati is developing a series of
pamphlets describing Operational Control Procedures for the
Activated Sludge Process. This series will include Part I
Observations, Part II Control Tests, Part III Calculation
Procedures, Part IV Sludge Quality, Part V Process Control
and an Appendix. Each one of these individual parts will be
released for distribution as soon as it is completed, though
not necessarily in numerical order. The original five-part
series will then be expanded to include special case
histories and refined process evaluation and control
techniques.
This pamphlet has been developed as a reference for
Activated Sludge Plant Control lectures I have presented at
training sessions, symposia, and workshops. It is based on
my personal conclusions reached while directing the
operation of dozens of different activated sludge plants.
This pamphlet is not necessarily an expression of
Environmental Protection Agency policy or requirements.
The mention of trade names or commercial products in
this pamphlet is for illustrative purposes and does not
constitute endorsement or recommendation by the
Environmental Protection Agency.
Alfred W. West
-------
TABLE OF CONTENTS
PAGE NO.
Control Test Data 1
Trend Charts
Moving Averages 7
Semi-Logarithmic Plots 11
Probability Plot Examples 14
Testing Equipment 20
Symbols and Terminology 23
-------
CONTROL TEST DATA
V\ASTEWATER TREATMENT PLANT
24 HR AVG
(TOTALIZER)
.V S A F !
MGD RSF
XSF
z ^
SLUDGE
BLANKET
nc PT._
RSC
XSC
DOB
R <; r. ^
RSC
; XSC r XSC
I
DOB ^r " ' DOR
R
X
D
D t P M
TURBID
, » ETC D i N IT
>- -
AERATiOM
INIT :' £"
1 HR "4-
IN
INIT
1 HR
IN
JH
1 HR
IN
D O
OUT
OUT
OUT
RAW
RAW
A T
RAW
A T
OUT
RAW
A T
VOVGHT TOTAL 2ER READING
AFI
RSF
XSF
COMMENTS and SPECIAL DATA
cc~
-------
CONTROL TEST DATA
Data from the control tests described in Part II
Control Tests should be recorded in an organized manner at
each test period. A generalized data sheet suitable for
this purpose is shown on the facing page.
The test times shown near the top of the sheet will not
be standard for each plant but will normally be determined
by personnel shift changes and diurnal flow or load
variation. At times additional centrifuge and depth of
blanket tests may be desireable. These data may be recorded
at the bottom of the sheet under comments and special data.
Except for the Settled Sludge Concentration (SSC)
values, all numbers recorded on the data sheet are observed
values. The SSC's are calculated as described in Part IIIA
- Calculation Procedures.
The two sketches below illustrate how the 0400
centrifuge and settlometer test data were used to develop
Settled Sludge Volume (SSV) and Settled Sludge Concentration
(SSC) curves to help analyze sludge quality.
A seperate column is provided on the data sheet for
averaging the days' data. Flows recorded in this column
should be totalizer values. These daily average values will
be further used to calculate moving averages and additional
process parameters.
-------
TREND CHARTS
Data from individual daily tests and calculations
should be graphically displayed on "Trend Charts" so that
operators coming on duty can tell process ^status at a
glance. At least once each day, and preferably during each
shift, the data from the settlometer and centrifuge tests,
the final effluent turbidity, the depth of blanket, and
other selected parameters should be posted on the Trend
Charts. These charts, usually kept on a wall in the
laboratory area where the tests are performed, contain much
of the data essential to the operation of an activated
sludge plant. They provide graphic illustrations of process
responses to selected operational controls.
Figures 1, 2 and 3 are copies of actual trend charts
maintained by Waste Treatment Branch personnel at a recent
technical assistance project. Final effluent turbidity and
other selected process parameters are also tabulated on
Figure 3. The heavy line through August 20 on these charts
delineates a change in operating mode from two aerators and
one clarifier to two aerators and two clarifiers.
-------
The symbols, control tests and calculation procedures
for determining the parameters illustrated on Figures 1, 2
and 3 have been explained in previous Parts of this series.
For convenient referencing, all symbols used in this
pamphlet series and their definitions are restated in
alphabetical order on pages 23 through 27.
It should be kept in mind that trend charts such as
these are really work sheets and are appropriate places for
posting notes or data that might otherwise be recorded in a
log book and then forgotten. For example, unusual
occurrences that might affect plant performance, such as
slugs of strong industrial wastes or toxic chemicals
entering the plant, heavy rains, power failures, etc. can be
noted directly on the trend charts. If this is done,
reasons for sudden upsets or process imbalance can be easily
identified.
When time permits, trend charts may be expanded to
provide plant personnel with greater insights into the
operation of their treatment plant. Certain information
should be drawn on semi-log paper to help determine
relationships between various process parameters, and the
moving averages developed to damp out any large day-to-day
variations that occur.
-------
IOOO -
17 it, /f 10 2 / 22 23 2
Figure 1
TYPICAL TREND CHART SHOWING SSV & SSC CURVES
-------
ESU^XSU
M T W T f 5
/
-------
M H \X/TF
AFI
I2SF
XSF
7 46
.254
.029
ADTtaTFL 15 9
'BOD/IOOOf? I9Z
F/M
2.fa5 2.34 2
.2fa4 ,2b8
FLOWS (.r
2 "ift 1.195 1.595 2 2fc>
403 ,49fo .519 .545
2 fc.4B 2 4>4\ 2 20fc 1575 I 45'j 2 foOC
IOJ8 1.110 I.Zfo I 04>3 .750 Ofar
14.9
Oii .055 .055 .O5O .02fo . O5* . 05B .047 .055 .044
AE.KATI010 TANiiC CHAGACT&I2IST1CS
12.2 II.S II fc
.13
3'<°/3.i
11.7
19.1
14.9
23.7
24
19 O 20.fa 15.6
240 II 0 20.2
.l& 07 .13
12.fa Ifo.S
22 S 199
.21= .22 .25 .105 .O8&
IOO .081
19.7 122
30.1
.189
3 S
OF2
C5OT
CFP
COD
54=1
.97
17
83
30
FINAL
85
113
11
6&
53O 4.OO 539
99 I 07 .76
,7fa
CHA2ACT&12ISTICS
341 311
1.20 9fo
12.6 11.3
10
54
9
45
12
2fo.4 32 1
41.1
.47
34.2
FIN/XL EFFLUEMT QUALITY'
12 5 4= 4 12 5-
Z'SS 2Q9
I.O7 173
2^0 ns
1.22 103
14,5
97
294
\9
10
6<9
fa
38
fe
44,1
AZ
I I
69.2 72.1 68.4 4O 4
39
1
34
3.
2O
OJ
5
6 -
O -1
Figure 3
TYPICAL TREND CHART SHOWING FINAL EFFLUENT TURBIDITY
AND A TABULATION OF SELECTED PROCESS PARAMETERS
-------
MOVING AVERAGES
Moving averages, especially those for 7- and 28-day
intervals, are useful for evaluating process responses to
operational control adjustments. The effects of a major
change in operating procedures are usually confirmed about a
week after the start of the new control procedures. The
development of a stable sludge, fully acclimated to the
change, usually takes about a month.
The 7-day moving average (7DMA), which reflects the
effects of low load Saturdays and Sundays as well as high
load Mondays and Tuesdays, permits a realistic review of
medium term process response. The 28-day moving average
(28DMA) permits evaluation of long-term stabilization
performance.
Figure 4 is a graph of sludge wasting data, showing the
daily data points, the 7-day moving average, and the 28-day
moving average. The individual data points show
considerable variation from day to day. By plotting a 7-day
moving average, the large variations are smoothed out and
the actual trends (increasing or decreasing wasting rates)
become more apparent. The 28-day moving average shows the
long term trends.
Table 1 includes the daily (24 hour) average, and the
7-day and 28-day moving average data that are plotted on
Figure 4.
The 7-day moving average for any given day is the
average of the data for that day and the six previous days.
For example, from Table 1f the 7-day moving average for
1/4/73 is 1.932. This is obtained by averaging the data for
1/4/73 and the six previous days, starting with 12/29/72:
12/29/72 5.058
12/30/72 0.0
12/31/72 1.374
I/ 1/73 2.459
^/ 2/73 0.960
1/ 3/73 1.598
I/ 4/73 2.076
7 /13.525
1.932 = 7-day moving avg.
-------
100
9.0
80
O 60
g
v^y 50
' 40
X
oT 30
I
P
2.0
S- I0
O 0,9
-J 0.8
^ 0.7
*n
0.6
0.5
dJ
o
><
LU
0.4
0.3>
Z4 HOUE. AVECAGE
28 DAY
MOVING AVERAGE
7 DAY MOVING AVElZAGe
ZEIZO \VA5TING,
i I i 1 I I i I 1 i i i I I I
13 ZO
MOVEMBEC. \97Z
21 4 II
Figure 4
MOVING AVERAGE PLOTS OF XSU DATA
18
\972
JA.M 73
-------
Table 1
24 HOUR AVERAGES, 7 DAY & 28 DAY MOVING AVERAGES OF XSU DATA
DATE
ll/ 6/72
ll/ 6/72
ll/ 7/72
ll/ 8/72
ll/ 9/72
11/10/72
11/11/72
11/12/72
11/13/72
11/14/72
11/15/72
11/16/72
11/17/72
11/18/72
11/19/72
11/20/72
11/21/72
11/22/72
11/23/72
11/24/72
11/25/72
11/26/72
11/27/72
11/28/72
11/29/72
11/30/72
12/ 1/72
12/ 2/72
12/ 3/72
12/ 4/72
12/ 5/72
12/ 6/72
XSU
ZltHRA
XSU
7 DMA
XSU
28DMA
BOUNDARY DATE *
6
10
9
10
7
9
7
5
0
0
0
0
0
0
0
1
2
2
2
2
0
0
5
6
7
9
3
3
3
10
7
.678
.873
.259
.586
.853
.600
.119
.750
.0
.0
.0
.0
.900
.870
.630
.350
.160
.520
.736
.772
.0
.0
.508
.624
.421
.120
.230
.120
.326
.091
.182
6
8
8
9
9
9
8
8
7
5
4
3
1
I
0
0
0
1
1
1
1
1
2
2
3
4
4
5
5
6
6
.678= 1
.775= 2
.937= 3
.349= 4
.050= 5
.142= 6
.853
.720
.167
.844
.332
.710
.967
.074
.343
.536
. 8 44
.204
.595
.863
.738
.648
.242
.880
.580
.492
.558
.003
.479
.133
.713
6.
8 .
8.
9.
9.
9.
8.
8 .
7.
6.
6.
5 ,
5 .
4,
4,
4.
4,
4
4
4,
3
3
3
3
4
4
it
4
4
It
3
678 =
775 =
937 =
349 =
050 =
142 =
,853 =
,465 =
524 =
,772 =
,156 =
,643 =
.278 =
.963 =
.675 =
.467 =
.331 =
.230 =
.152 =
.083 =
.888 =
.712 =
.790 =
.908 =
.048 =
*
1
2
3
4
5
6
7
8
a
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
.243=26
.206 =
.167
.047
.020
.945
27
DATE
xsu
2UHRA
127 7/72
127 8/72
12/ 9/72
12/10/72
12/11/72
12/12/72
12/13/72
12/H/72
12/15/72
12/16/72
12/17/72
12/18/72
12/19/72
12/20/72
12/21/72
12/22/72
12/23/72
12/2it/72
12/25/72
11/26/72
12/27/72
12/28/72
12/29/72
12/30/72
12/31/72
I/ 1/73
I/ 2/73
I/ 3/73
I/ 4/73
I/ 5/73
3
It
It
5
5
6
5
5
5
3
it
6
It
it
3
1
0
1
0
6
lit
8
5
0
1
2
0
1
2
1
.08U
.098
.831
.2U2
.741
.750
.580
.058
.36lt
.It68
.368
.it It It
.599
.327
.037
.732
.907
.818
.801
.8511
.019
.188
.058
.0
.371*
.U59
.960
.598
.076
.577
XSU
7 DMA
XSU
2 8 DMA
5.593
It.876
5.105
5.1|08
5.753
5.275
5.0lt7
5.329
5.509
5.315
5.190
.290
.95I|
.775
.487
.968
.602
.238
.It32
.783
.167
It.903
.378
. 21t8
.185
.It22
.580
.805
1.932
1. It 3 5
.677
,5lt3
.373
,306
.306
3.5lt7
7U6
3.927
It.118
It.210
it.335
U.5l|2
It.651
It.729
If .7lt7
711
6lt5
710
738
786
051
078
933
817
It.755
,72lt
.398
.199
.163
It.073
LEGEND:
XSU = EXCESS SLUDGE UNITS WASTED (IN 1,000 SLUDGE UNITS)
24HRA = 24-HOUR (DAILY) AVERAGE
7DMA = 7-DAY MOVING AVERAGE
28DMA = 28-DAY MOVING AVERAGE
BOUNDARY nATE = THE FIRST DAY OF DATA INCLUDED III THE CALCULATIONS
* = INDICATES THE NUMBER OF DAILY DATA POINTS INCLUDED IN THE
CALCULATIONS, WHERE LESS THAN 7 (OR 28) ARE AVAILABLE.
-------
Similarly, the 7-day moving average for the next day,
1/5/73, is the average of the data for that day and the six
previous days, starting with 12/30/72:
12/30/72 0.0
12/31/72 1.374
^/ 1/73 2.459
1/ 2/73 0.960
1/ 3/73 1.598
1/ 4/73 2.076
V 5/73 1.577
7 /I 0.044
1.435 = 7-day moving avg.
The 7-day moving average for 1/5/73 could also be
calculated easily from the previous day's calculations by
subtracting the data for 12/29/72 (5.058) from the previous
day's subtotal (13.525), adding the data for 1/5/73 (1.577)
and dividing by 7:
13.525
- 5.058 (12/29/72)
8.467
+ 1.577 (1/5/73)
7 /10.044
1.435 = 7-day moving avg.
A 28-day moving average is derived by the same type of
calculation.
When working with a new set of data, such as at the
start of a new operational control phase, it is necessary to
start with a progressive average (rather than a 7-day moving
average) until seven days of data are included. Note that
the 7 DMA column on Table 1 does not start with a true 7-day
moving average, since the time period covered is less than
seven days. The initial values for the first 6 days shown
in the 7 DMA column are progressive averages until 11/12/72,
at which point they become true 7-day moving averages.
Similarly, the initial values for the first 27 days in the
28 DMA column are progressive averages until 12/3/72, when
they become 28-day moving averages.
10
-------
SEMI LOGARITHMIC PLOTS
Process responses (SSV, ATC, SSC, turbidity, etc.) to
control adjustments are normally plotted on a test-by-test
basis to permit process evaluation. Semi-logarithmic plots
are useful when one wishes to compare the rate of change of
various parameters to a process adjustment because it
permits direct observation of rate changes between the
parameters regardless of their magnitudes.
Consider the following hypothetical example as
displayed on the two graphs below. Two identical data sets
(A and B) are plotted on each graph. The left graph is
drawn on rectangular coordinate paper, the right on semi-
logarithmic paper. Note how readily the trend similarity
becomes apparent from a comparison of the semi-logarithmic
curves. In this example, the plotted parameters have
identical slopes and remain parallel to each other. The
rectangular plot of the same parameters does not readily
display that the rate changes, defined by their slopes, are
identical. The probable relationship between parameters A
and B might have been overlooked if only rectangular
coordinate paper had been used.
10 0
9 0
8 0
7 0
6 0
5 0
4 0
3 0
2 0
1 0
I I
10 0
9 0
8 0
7 0
6 0
1 0
0 9
T W T
RECTANGULAR PLOT
T W T
SEMI-LOGARITHMIC PLOT
11
-------
Now consider two plots drawn from the actual plant data
shown below:
Day/Date
M 12/18/72
T . 19
W 20
T 21
22
23
F
S
S
M 12/25/72
T 26
W 27
T 28
F 29
S 30
S 31
M
T
W
T
F
S
S
1/1/73
2
3
4
5
6
7
M
T
W
T
F
S
S
1/8/73
9
10
11
12
13
14
TABLE 2
Turb
(JTU)
9
9
9
13
12
13
,93
,53
,13
,00
,33
,53
13.87
21.67
17.33
19.00
20.00
17.67
13.30
9.80
6.90
6.30
6.10
5.77
8.10
9.25
6.57
6.47
5.03
3.67
5.40
5.90
10.90
10.47
CSDT
(lirs)
0.69
1 .09
1.73
3.32
3.17
2.85
3.96
4.04
4.61
3.36
3.29
2.81
2.88
2.29
1.36
1.10
0.84
0.78
0.92
0.92
0.91
0.69
0.74
0.79
1 .43
1.25
1.49
1.39
The upper illustration on Figure 5 shows a rectangular
plot of final effluent turbidity and CSDT (Clarifier Sludge
Detention Time) versus Time. The lower illustration is a
plot of the same data on semi-logarithmic paper. When
plotted on semi-log paper, the similarity between the two
curves becomes evident. The possible cause and effect
relationship between CSDT and turbidity might have been
overlooked if only rectangular paper had been used.
12
-------
10
F
D
S 2
20
ia
it
14.
10
V
o
J
li.
U-
OJ
4
IZ
I I I I
MTNVTF SS|MT\VTF5 S I M T \V T FS SMTV/TFS S
\a 19 2O 21 12 23 24 I 25 2fc 71 28 V> ?£> 31 I I ~i 3 4 S 4= 1 8 9 10 11 12. 13 14
I I I I I I I
aJ
F
o
i-,
OJ .6
D .fa
uj e>
5EM\ - LOO, PLOT
loo
so
80
70
bO
SO
4O
10
8
b
5
y
D
OJ
_J
U-
U-
3 J
4
Z
2 U-
d
I I I I I
IMTVTFS S|MT\VTFSS
I ia 19 20 Zl ZZ 2^ 24 1 25 ?b 27 78 W 30 3.1
MT\VTF ss
I 2 3 45 fo 1
M T \V T F S SI
89 10 H It n \A I
Figure 5
COMPARISON OF RECTANGULAR AND SEMI-LOGARITHMIC PLOTS
-------
PROBABILITY PLOT EXAMPLES
When collected data are plotted on probability paper,
they can be used to predict frequencies at which certain
events may occur. For example, from a probability plot of
past treatment plant data, one may estimate the percentage
of time that the hydraulic capacity of the plant may be
exceeded, and the percentage of time that the final effluent
quality may be less than acceptable limits.
Two examples of probability plots are presented.
Bacteriological data, conforming to logarithmic growth
rates, are usually plotted on probability paper with a
logarithmic vertical scale (Figure 6). Chemical data are
usually plotted on probability paper with a uniformly
divided vertical scale (Figure 7).
The first step in preparing a probability plot consists
of reorganizing the raw data, regardless of collection date,
into an orderly progression starting with the smallest
number and finishing with the largest. Such a progression
of 50,000 through 1,600,000+ for the 13 bits of data in the
first example is shown in the second column of Table 3.
TABLE 3
COLIFORM PROBABILITY PLOT EXAMPLE
Coliform Density
Tabulated
Chronologically
330,000
50,000
820,000
220,000
1 ,600,000
350,000
110,000
700,000
130,000
820,000
1,600,000 +
230,000
78,000
- MPN/100 ml
Ranked in
Ascending
Order
50,000
78,000
110,000
130,000
220,000
230,000
330,000
350,000
700,000
820,000
820,000
1 ,600,000
1,600,000 +
"Exact"
Plotting
Position
N = 13
4.8
12.2
19.2
27.3
34.9
42.5
50.0
57.5
65.1
72.7
80.2
87.8
95.2
NOTE: 541,000
330,000
Arithmetic Mean
Probability Mean (Fig. 7)
14
-------
The plotting position, shown in the third column of
Table 3 for each data item, can then be obtained directly
from Table 4 if 50 or less data points are to be plotted.
Plotting positions for sample sizes greater than 50 can be
calculated according to the formula on Table 4, page 18.
For this sample size of 13, the plotting positions ranged
from "less than" 4.855 of the time for 50,000 to "less than"
95.2% of the time for 160,000+.
The coliform concentrations were then plotted according
to their respective plotting positions. The completed
probability plot of the coliform data is illustrated in
Figure 6.
At first glance, the large and irregular day-to-day
differences in coliform concentrations shown in column one
of Table 3 appeared irreconcilable. But the probability
plot of this same information displayed the data in an
orderly fashion and permitted logical evaluation of the
survey results. As shown on Figure 6, the mean density was
330,000 MPN/100 ml and it could be expected that the
concentration would most probably equal or exceed 58,000 90%
of the time, and equal or exceed 1,850,000 *\Q% of the time.
Figure 7 is a probability plot of final effluent BODS
concentrations and aeration tank BODS loadings at an
activated sludge plant. The data were arranged as in the
previous example, and the plotting positions were determined
from the formula on Table 4. In this example normal
(rectangular coordinate) probability paper was used.
15
-------
I *IO
IO 15 20 3O 4O 5O iM 10 SO 85 9O 95 98%
COUFOR.M TEST
EQilAl,
OE. &XC&ED 1,850,000
10% OF THE TIME
UlO
Figure 6
SEMI-LOGARITHMIC PROBABILITY PLOT OF COLIFORM DATA
-------
80
12 5 10 ZQ 30 4O 50 6O 70 8O 90 95 98 99
Figure 7
RECTANGULAR PROBABILITY PLOT OF LOADING AND BOD DATA
-------
Table 4
PLOTTING POSITIONS FOR NORMAL PROBABILITY PAPER
Ordinal Sample Size Ordinal
No. 2 3 It 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
28.6 19.9 15.2 12.2 10.3 8.8 7.7 6.9| 6.2 5.6 5.2 4.8
71.4 50.0 38.3 31.0J26.0 22.5 19.7 17.6 15.8 14.4 13.2 12.2
80.1 61.7 50.0 42.0 36.2 31.8 28.4 25.6 23.3 21.4 19. B
84.8 69.0 58.0 50.0 43.9 39.2 35.3 32.2 29.6 27.3
87.8 74.0 63.8 56.1 50.0 45.1 41.1 37.8 34.9
89.7 77.5 68.2 60.8 54.9 50.0 45.9 42.5
91.2 80.3 71.6 64.7 58.9 54.1 50.0
92.3 82.4 74.4 67.8 62.2 57.5
93.1 84.2 76.7 70.4 65.1
93.8 85.6 78.6 72.7
94.4 86.8 80.2
94.8 87.8
95.2
4.4 4.1
11.4 10.6
18.4 17.2
25.4 23.7
32.4 30.3
39.5 36. S
46.5 43.4
53.5 50.0
60.5 56.6
67.6 63.1
74.6 69.7
81.6 76.3
88.6 82.8
95.6 89.4
95.9
3.9 J.6
9.9 9.4
16.1 15.2
22.3 21.0
28.4 26.8
34.6 32.6
40.7 38.4
46.9 44.2
53.1 50.0
59.3 55.8
65.4 61.6
71.6 67.4
77.7 73.2
83.9 79.0
90.1 84.8
96.1 90.6
96.4
3.4 3.3
8.9 8.4
14.3 13.6
19.8 18.8
25.3 24.0
30.8 29.2
36.3 34.4
41.8 39.6
47.2 44.8
52.8 50.0
58.2 55.2
63.7 60.4
69.2 65.6
74.7 70.8
80.2 76.0
85.7 81.2
91.1 86.4
96.6 91.6
96.7
3.1 2.9l 2.8 2.7
8.0 7.7
12.9 12.3
17.9 17.1
22.8 21.8
27.8 26.4
32.7 31.2
37.6 35.9
42.6 40.5
47.5 45.2
52.5 50.0
57.4 54.8
62.4 59.5
67.3 64.1
72.2 68.8
77.2 73.6
82.1 78.2
87.1 82.9
92.0 87.7
96.9 92.3
97.1
7.2 6.8
11.7 11.3
16.4 15.6
20.6 19.8
25.1 24.2
29.8 28.4
34.1 32.6
38.6 37.1
43.3 41.3
47.6 45.6
52.4 50.0
56.7 54.4
61.4 58.7
65.9 62.9
70.2 67.4
74.9 71.6
79.4 75.8
83.6 80.2
88.3 84.4
92.8 88.7
97.2 93.2
97.3
2.6 2.4T 2.4 2.3 2.2 2.1
6.7 6.4
10.7 10.4
14.9 14.2
18.9 18.1
23.3 22.4
27.4 26.1
31.6 30.2
35.6 34.1
39.7 38.2
43.6 42.1
48.0 46.0
52.0 50.0
56.4 54.0
60.3 57.9
64.4 61.8
68.4 65.9
72.6 69.8
76.7 73.9
81.1 77.6
85.1 81.9
89.3 85.8
93.3 89.6
97.4 93.6
97.6
6.2 5.9
9.9 9.5
13.8 13.3
17.6 16.9
21.5 20.6
25.1 24.2
29.1 28.1
33.0 31.6
36.7 35.2
40.5 39.0
44.4 42.5
48.0 46.4
52.0 50.0
55.6 53.6
59.5 57.5
63.3 61,0
67.0 64.8
70.9 68.4
74.9 71.9
78.5 75.8
82.4 79.4
86.2 83.1
90.1 86.7
93.8 90.5
97.6 94.1
97.7
5.7 5.5
9.2 8.9
12.7 12.3
16.4 15.9
19.8 19.2
23.3 22.7
27.1 26.1
30.5 29.5
34.1 33.0
2.1 2.0
5.J 5.2
8.7 8.4
11.9 11.5
15.2 14.7
18.7 17.9
21.8 21.2
25.1 24.6
28.4 27.4
31 .9 30.9
37.4 36.3135.2 34.1
41.3 39.7
44.8 43.3
48.4 46.4
51.6 50.0
55.2 53.6
58.7 56.7
62.6 60.3
65.9 63.7
69.5 67.0
72.9 70.5
76.7 73.9
80.2 77.3
83.6 80.8
87.3 84.1
90.8 87.7
94.3 91.1
97.8 94.5
97.9
38.6 37.1
41.7 40.5
45.2 43.6
48.4 46.8
51.6 50.0
54.8 53.2
58.3 56.4
61.4 59.5
64.8 62.9
68.1 65.9
71.6 69.1
74.9 72.6
78.2 75.4
81.3 78.8
84.8 82.1
88.1 85.3
91.3 88.5
94.7 91.6
97.9 94.8
98.0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
:es:
Statistical Tables for Biological Agricultural and Medical Research, by Fisher and Yates, Hafner Pub. Co., '63, Table XX, 94-95
:ables of Normal Probability Functions, U. S. Government Printing Office, '53, Table I, 2-338
'earson, E. and Hartley, H., Biometrika Tables for Statisticians Volume I, Cambridge University Press, '54, Table 28, 175, Table 1,
References:
(1) St
(2) T
(3) P
104-110
-------
Table 4
PLOTTING POSITIONS FOR NORMAL PROBABILITY PAPER
Ordtnml Ordinal
Ho. 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
3
3
3
3
3
4
4
4
4
44
4
4
4
4
4
5
1.92 1.88
4.9 4.8
8.1 7.8
1.1 10.9
4.2 13.8
7.4 16.9
0.6 19.8
3.6 23.0
6.8 25.8
9.8 28.8
3.0 31.9
5.9 34.8
9.0 37.8
2.1 40.9
5.2 44.0
8.4 46.8
1.6 50.0
4.8 53.2
7.9 56.0
1.0 59.1
64.1 62.2
67.0 65.2
70.2 68.1
73.2 71.2
76.4 74.2
79.4 77.0
82.6 80.2
85.8 83.1
88.9 86.2
91.9 89.1
95.1 92.2
98. OB 95.2
98.12
1.83 1.74
4.6 4.6
7.6 7.4
10.6 10.2
13.3 13.1
16.4 15.9
19.2 18.7
22.4 21.5
25.1 24.5
28.1 27.4
30.9 30.2
34.1 33.0
36.7 35.9
39.7 38.6
42.9 41.3
45.6 44.4
48.4 47.2
51.6 50.0
54.4 52.8
57.1 55.6
60.3 58.7
63.3 61.4
65.9 64.1
69.1 67.0
71.9 69.8
74.9 72.6
77.6 75.5
80.8 78.5
83.6 81.3
86.7 84.1
89.4 86.9
92.4 89.8
95.4 92.6
98.17 95.4
98.26
1.70 1. 66 | 1.62 1.58
4.5 4.3
7.2 6.9
10.0 9.7
12.7 12.3
15.4 15.2
18.1 17.9
20.9 20.3
23.6 23.3
26.4 25.8
29.5 28.4
31.9 31.2
34.8 33.7
37.4 36.7
40.5 39.4
43.3 42.1
46.0 44.4
48.8 47.2
51.2 50.0
54.0 52.8
56.7 55.6
59.5 57.9
62.6 60.6
65.2 63.3
68.1 66.3
70.5 68.8
73.6 71.6
76.4 74.2
79.1 76.7
81.9 79.7
84.6 82.1
87.3 84.8
90.0 87.7
92.8 90.3
95.5 93.1
98.30 95.7
98.34
4.2 4.1
6.8 6.7
9.4 9.2
12.1 11.7
14.7 14.2
17.4 16.9
19.8 19.5
22.7 22.1
25.1 24.5
27.8 27.1
30.5 29.5
33.0 32.3
35.6 34.8
38.2 37.1
40.9 39.7
43.6 42.5
46.0 44.8
48.8 47.6
51.2 50.0
54.0 52.4
56.4 55.2
59.1 57.5
61.8 60.3
64.4 62.9
67.0 65.2
69.5 67.7
72.2 70.5
74.9 72.9
77.3 75.5
80.2 77.9
82.6 80.5
85.3 83.1
87.9 85.8
90.6 88.3
93.2 90.8
95.8 93.3
98.38 95.9
98.42
1.54 1.50
4.0 3.9
6.4 6.3
9.0 8.7
11.5 11.1
14.0 13.6
16.4 16.1
18.9 18.4
21.5 20.9
23.9 23.3
26.4 25.8
28.8 28.1
31.2 30.5
33.7 33.0
36.3 35.6
39.0 37.8
41.3 40.1
43.6 42.9
46.4 45.2
48.8 47.6
51.2 50.0
53.6 52.4
56.4 54.8
58.7 57.1
61.0 59.9
63.7 62.2
66.3 64.4
68.8 67.0
71.2 69.5
73.6 71.9
1.46 1.43 1.39 1.36
3.8 3.7
6.2 6.1
8.5 8.4
10.9 10.6
13.3 12.9
15.6 15.4
18.1 17.6
20.3 20.0
22.7 22.4
25.1 24.5
27.4 26.8
29.8 29.1
32.3 31.6
34.5 33.7
37.1 35.9
39.4 38.6
41.7 40.9
44.0 43.3
46.4 45.2
48.8 47.6
51.2 50.0
53.6 52.4
3.6 3.5
5.8 5.7
8.1 7.9
10.4 10.2
12.7 12.3
14.9 14.7
17.1 16.9
19.5 18.9
21.8 21.2
23.9 23.6
26.1 25.8
28.4 27.8
30.9 30.2
33.0 32.3
35.2 34.5
37.4 36.7
39.7 39.0
42.1 41.3
44.4 43.3
46.4 45.6
48.8 47.6
51.2 50.0
56.0 54.8 53.6 52.4
58.3 56.7 55.6 54.4
60.6 59.1 '57.9 56.7
62.9 61.4 60.3 58.7
65.5 64.1 62.6 61.0
67.7 66.3 :64.8 63.3
70.2 68.4 67.0 65.5
76.1 74.2 J72.6 70.9 ]69.1 67.7
78.5 76.7 p4.9 73.2 71.6 69.8
81.1 79.1 77.3 75.5 73.9 72.2
83.6 81.6 79.7 77.6 '76.1 74.2
86.0 83.9 181.9 80.0 78.2 76.4
88.5 86.4J84.4 82.4 80.5 78.8
91.0 88.9 86.7 84.6 .82.9 81.1
93.6 91.3 189.1 87.1
96.0 93.7
96.46 96.1
91.5 89.4
93.8 91.6
98.50196.2 93.9
198.54 96.3
98.57
85.1 83.1
87.3 85.3
89.6 87.7
91.9 89.8
94.2 92.1
96.4 94.3
98.61 96.5
98.64
1.32 1.32
3.4 3.4
5.6 5.5
7.8 7.6
10.0 9.7
12.1 11.9
14.2 14.0
16.4 16.1
18.7 18.1
20.9 20.3
23.0 22.4
25.1 24.5
27.4 26.7
29.5 28.8
31.6 30.9
33.7 33.0
35.9 35.2
38.2 37.4
40.1 39.4
42.5 41.7
44.4 43.6
46.8 45.6
48.8 48.0
51.2 50.0
53.2 52.0
55.6 54.4
57.5 56.4
59.9 58.3
61.8 60.6
64.1 62.6
66.3 64.8
68.4 67.0
70.5 69.1
72.6 71.2
74.9 73.2
77.0 75.5
79.1 77.6
81.3 79.7
83.6 81.9
85.8 83.9
87.9 86.0
90.0 88.1
92.2 90.3
94.4 92.4
96.6 94.5
98.68 96.6
98.68
1.29 1.25
3.3 3.2
5.4 5.3
7.5 7.4
9.5 9.3
11.7 11.3
13.8 13.3
15.9 15.4
17.9 17.4
20.0 19.5
22.1 21.5
24.2 23.6
26.1 25.5
28.1 27.8
30.2 29.8
32.3 31.6
34.5 33.7
1.22
3.2
5.2
7.2
9.2
11.1
13.1
15.2
17.1
19.2
21.2
23.0
25.1
27.1
29.1
31.2
33.0
36.7 35.9 135.2
38.6 37.8
40.5 39.7
37.1
39.0
42.9 41.7 40.9
44.8 44.0 '42.9
46.8 46.0 44.8
48.8 48.0 ,46.8
51.2 50.0 ,48.8
53.2 52.0 51.2
55.2 54.0
57.1 56.0
53.2
55.2
59.5 58.3 '57.1
61.4 60.3 59.1
63.3 62.2 61.0
65.5 64.1 J62.9
67.7 66.3
69.8 68.4
64.8
67.0
71.9 70.2 68.8
73.9 72.2
70.9
75.8 74.5 72.9
77.9 76.4
80.0 78.5
82.1 80.5
84.1 82.6
86 . 2 84 . 6
88.3 86.7
90.5 88.7
92.5 90.7
94.6 92.6
96.7 94.7
98.71 96.8
98.75
74.9
77.0
78.8
80.8
82.9
84.8
86.9
88.9
90.8
92.8
94.8
96.8
"98.78
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
For sample sizes larger than 50
plotting position is estimated
as:
100 (ordinal number - 0.5)
sample size
Sample Size Ordinal number
51
100(1-0.5)
51
100(2-0.5)
51
100(51-0 5)
M
-------
TESTING EQUIPMENT
Some special equipment for operational control testing
are used in the NFIC-C Procedures. Basically a settlometer,
centrifuge, turbidimeter, and optical sludge blanket finder
are needed.
The construction of a typical sludge blanket finder is
shown in Figure 8. Approximate prices (1973) and types of
control test equipment that have been used by the Waste
Treatment Branch are as follows:
Blanket Finder Parts
Site Glass - Part No. 4045 for 1 1/2" pipe $5.00
Gitz Mfg. Co.
1846 South Kilbourn Ave.
Chicago, Illinois 60623
Use Schedule 40 aluminum pipe. Tape the tube
every 0.5 ft. starting at the site glass to
facilitate reading the blanket depth. Faster
readings may be obtained if distinctive markings
are used at the 5 ft. and 10 ft. points.
Mailory Direct Reading Settlometer
5" dia. x 7" high, 2 liter graduated cyl. $24.00
Scientific Glass Apparatus Co.
735 Broad Street
Bloomfield, New Jersey 07003
Turbidimeter
Hach Model 2100-A Laboratory Turbidimeter $525.00
Hach Chemical Co.
Box 907
Ames, Iowa 50010
20
-------
Single Pole
Toggle Switch
6 Volt Battery »
w/Screw Terminals
(Use Tape or Hose Clamps
to Secure Switch and
Battery to Pole)
Distinctive 10ft Marker
Wires to Battery
and Switch
4in. Schedule 40
Aluminum Pipe
Distinctive 5ft Marker
Place Tape on 0.5ft
and 1.0ft Intervals
to Hold Wire and Aid
in Determining DOB
SEE DETAIL
'\'
-------
Clinical Centrifuge, I.E.G. No. 428 $208.00
1 - Head, Trunion, 6-place, 15 ml.,
I.E.G. No. 221 $59.00
6 - Shields, Cornell Style, 15 ml.,
I.E.G. No. 303 $31.50/6
1 Pk - Replacement Thrust Cushions,
Rubber, I.E.G. No. 570 $2.40
International Equipment Co.
300 Second Ave.
Needham Heights, Mass. 02194
Centrifuge Tubes - A.P.I.
1 Dz - Kimax No. 45170 $30.00/Dz
Laboratory Timer
Interval, electric, 60-minute, with
alarm, 2 switches and elapsed time
circuit $35.00
Matheson Scientific
12101 Centron Place
Cincinnati, Ohio 45246
Note; Some of this special testing equipment is not
listed"in generalized laboratory equipment catalogs.
Manufacturers1 catalog numbers are used only to identify
types of equipment and this does not constitute an
endorsement of any manufacturer or supplier.
22
-------
SYMBOLS AND TERMINOLOGY
USED IN
ACTIVATED SLUDGE PROCESS CALCULATIONS
AAG - Aeration Age (Number of days sludge subjected
to aeration)
ADT - Aeration Tank Detention Time (Hours)
AFI - Aeration Tank Wastewater F_low-In (mgd
or cu m/day) ~" ~~
AGE - Sludge Age (Days)
ASDT - Aeration Tank SJLudge Detention Time (Hours)
ASA - Aeration Tank Surface Area
ASF - Aeration Tank Surface Area (Square Feet)
ASM - Aeration Tank £>urface Area (Square Meters)
ASU - Aeration Tank Sludge Units
ATC - Aeration Tank Concentration (% by Centrifuge)
ATCm - Mean Aeration Tank Concentration
ATCn - Aeration Tank Concentration (Final Bay)
AV - Aeration Tank Volume
AVF - Aeration Tank Volume (Cubic Feet)
AVG - Aeration Tank Volume (Gallons)
AVM - Aeration Tank Volume (Cubic Meters)
AWDT - Aeration Tank Waste Detention Time
BLT - Sludge Blanket Thickness
BLV - Sludge Blanket Volume
23
-------
BOD - Biochemical Oxygen Demand (5-day unless
stated otherwise)
BODd - Calculated Net Five-Day Biochemical Oxygen
Demand of waste water and" the "liquid"
portion" of the return sludge at the
aeration tank entrance (diluted waste water)
BODi - Five-Day Biochemical Oxygen Demand of the
waste water entering Ti_n) the aeration tank
BODo - Five-Day Biochemical Oxygen Demand of the
final claFifier effluent (out)
CDT - Final Clarifier Detention Time (Hours)
CFI - Final Clarifier F_low-I^i (mgd or cu m/day)
CFL - Final C_larifier Sludge Floor Loading
CFO - Final Clarifier F_low-Out (mgd or cu m/day)
CMC - Final Clarifier Mean Sludge Concentration
COD - Chemical Oxygen Demand
CSA - Final Clarifier Surface Area (Square Feet)
CSM - Final Clarifier Surface Area (Square Meters)
CSC - Final Clarifier Sludge Concentration
CSDT - Final Clarifier Sludge .Detention Time (Hours)
CSF - Final Clarifier Sludge Flow (RSF + XSF)
CSFD - Final C_larifier Sludge FJLow Demand
CSU - Final Clarifier S_ludge Units
CSUI - Final Clarifier Sludge Units - In
CSUO - Final Clarifier Sludge Units - Out Of Clarifier
CV - Final CJLarifier Volume
CVF - Final Clarifier Volume (Cubic Feet)
CVG - Final Clarifier Volume (Gallons)
-------
CVM - Final Clarifier Volume (Cubic Meters)
CWD - Final Clarifier Mean Water Depth
DOB - Depth Of Sludge Blanket
ESU - Final Effluent Sludge Units (Total Suspended
Solids lost in Final EFfluent expressed as SLU)
FEC - Final Effluent Concentration (Total Suspended
Solids converted" to % by Centrifuge - FETSS/WCR)
FET - Final Effluent Turbidity (JTU)
FETSS - Final Effluent Total Suspended Solids (mg/1)
j - Suffix Notation (Used to indicate a
particular aeration tank bay)
j-1 - Suffix Notation (Used to indicate the
bay preceding the bay of reference, j)
JTU - Jackson Turbidity Units
LOD - Load_ (Ibs BOD/day to aeration tanks)
LODk - Load_ (kg BOD/day to aeration tanks)
MLTSS - Mixed Liquor Total Suspended Solids (mg/1)
MLVSS - Mixed Liquor Volatile Suspended Solids (mg/1)
OFR - Final Clarifier Surface Overflow Rate
(Gal/day/sq ft or cu m/day/sq m)
PEC - Primary Effluent Concentration (PETSS / WCR)
PET - Primary Effluent Turbidity (JTU)
PETSS - Primary Effluent Total Suspended S_olids (mg/1)
PFI - Primary F_low Into Primary Clarifiers
PFO - Primary F_low Out Of Primary Clarifiers
PSF - Primary S_ludge Flow (mgd or cu m/day)
PSAF - Primary Clarifier Surface Area (Square Feet)
25
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PSAM - Primary Clarifier Surface Area (Square Meters)
PVF - Primary Clarifier Volume (Cubic Feet)
PVG - Primary Clarifier Volume (Gallons)
PVM - P_rimary Clarifier Volume (Cubic Meters)
RFD - Return Sludge Flow Demand
RFP - Return Sludge F_low Percentage (RSF as a
$" of AFI by meter)
RSC - Return Sludge Concentration (% by Centrifuge)
RSF - Return Sludge F_low (mgd or cu m/day)
RSP - Return S_ludge Percentage (Calculated from
ATC, RSC, and PEC)
RSTSS - Return S_ludge Total Suspended S_olids (mg/1)
RSU - Return S_ludge Units (To aeration tanks)
RSVSS - Return S_ludge Volatile Suspended Solids (mg/1)
SAH - S_ludge Aeration Hours (Hours/day in aeration tank)
SAP - S_ludge Aeration Hours In Percent Of Day
SCR - Sludge Concentration Ratio (SSC60 / RSC)
SCY - Sludge Cycles (per day)
SDR - S_ludge Distribution Ratio (ASU / CSU)
SLR - Sludge Ratio (RSC / ATC)
SLU - S_ludge Units
SSC - Settled SJLudge Concentration (% by Centrifuge)
SST - Settled S_ludge Time
SSV - Settled S_ludge Volume
TDT - Total Sludge Detention Time (ADT + SDT in Hours)
TFI - Sludge Thickener Flow-In (mgd or cu m/day)
26
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TFL - Total Flow (ragd or cu m/day out of aeration
tank)
TFO - Thickener Flow Out (mgd or cu m/day)
TKR - Tank Ratio (AVG / CVG)
TSF - Thickener Sludge Flow (ragd or cu m/day)
TSS - Total Suspended £olids (mg/1)
TSU - Total Sludge Units (ASU + CSU)
TXU - Total Excess Sludge Units To Waste (ESU + XSU)
WCR - Weight To Concentration Ratio (MLTSS / ATC)
WCRS - Weight To Concentration Ratio - Return Sludge
TRSTSS / RSC) ~
V - Volume Of Aeration Tank (gal, cu ft, or cu m)
XFP - Excess Sludge FJLow (as Percent of AFI)
XMF - Excess Mixed Liquor Sludge F_low To Waste
(mgd or cu m/day) ~
XRF - Excess Return Sludge Flow To Waste
(mgd or cu m/day)
XSC - Excess SJLudge Concentration (% by Centrifuge)
XSF - Total Excess Sludge Flow To Waste
(mgd or cu m/cfay) ~
XSU - Total Excess Sludge Units To Waste
NOTE: It is necessary, especially in Part IIIB, to use
subscript notation to refer to particular bays within an
aeration tank or to refer to flow values into a particular
bay of an aeration tank. Several parameters, ADT, AFI, ATC,
AV, AVG, TFL and V are combined with subscripts in Part
IIIB. With these parameters, the reader need only remember
that the number refers to the bay of the aeration tank. For
example, ATC2 means the concentration of the mixed liquor, %
by centrifuge, in the second bay of the aeration tank. AVG3
means the volume of the third bay expressed in gallons.
TFLj means the total flow through the "j th" bay, and
finally, TFLj-1 means the total flow through the bay
preceding the "j th" bay.
27 * U.S. GOVERNMENT PRINTING OfTICE: 1974 758-494/1180
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AERATION TANKS
FINAL CLARIFIER
PFO
AFI
FROM PRIMARY
RECYCLE FROM
>
THICKENER & DRAINS
RSF @ RSC
XSF @ XSC
TO SLUDGE HANDLING
TFL
CFI
@ ATC \ @ ATC
CSF
XMF I @ ATC
@ RSC
CFO
-^
@ FEC
M FLOW METER
SLUDGE PUMP
TYPICAL CONVENTIONAL
ACTIVATED SLUDGE PLANT
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