-------
TABLE 8
AVERAGE SPECIFIC CONDUCTANCE (MICROMHOS PER CM)
July 1958
August
September
October
November
December
January 1959
February
March
April
R
675
—
—
925
1167
1100
1100
1083
1
4-20
508
500
600
613
563
600
870
913
900
2
400
395
407
393
314
353
450
589
700
567
3
480
488
510
600
619
513
617
833
881
850
4
400
368
433
467
595
444
617
742
875
908
5
450
455
450
556
588
463
600
767
850
917
6
•*«•»
438
400
430
395
380
400
467
575
517
TABLE 9
AVERAGE ALKALINITY CONCENTRATIONS (PPM) AND PERCENT REDUCTION
TOTAL ALKALINITY
CO,,
HCO.,
TOTAL
July 1958
Aug.
Sept.
Oct.
Nov.
Dec.
Jan. 1959
Feb.
March
April
10 Mo. Av.
% Red
1
37
46
29
6
22
5
0
0
0
13
16
2
16
47
20
15
19
27
29
0
25
29
23
3
0
37
30
32
8
3
0
0
0
21
13
4
15
45
22
31
23
3
0
0
0
4
14
5
22
49
37
37
30
2
0
0
0
15
19
6
20
30
17
18
9
15
14
12
52
42
23
R
277
274
273
280
288
281
294
289
266
290
281
1
124
131
147
192
149
194
216
211
202
195
176
2
159
109
139
157
146
135
133
186
167
169
150
3
181
134
140
141
166
182
196
209
211
184
174
4
180
95
143
137
144
169
187
205
219
206
168
5
173
106
121
130
137
179
196
203
213
192
165
6
144
119
137
139
146
145
143
145
98
104
132
R
277
274
273
280
288
281
294
289
266
290
281
1.
161
177
176
198
171
199
216
211
202
208
192
^o
Jii
2
175
156
159
172
165
162
162
186
192
188
172
OQ
3
181
171
170
173
174
185
196
209
211
205
187
"V
4
195
140
165
178
167
172
187
205
219
210
184
or
JD
5
195
155
158
167
167
181
196
203
213
207
184
or
-55
6
164
149
154
157
155
160
157
157
150
146
155
J ^
4-9
25
-------
TABLE 10
AVERAGE OXYGEN CONCENTRATIONS (PPM)
July 1958
August
September
October
November
December
January
February
March
April
10 Mo. Av.
1
11.3
21.0
16.0
4.7
14.1
4.7
0
0
0
10.2
8.2
2
4.3
20.7
14.6
11.8
12.5
11.5
10.8
1.4
9.0
9.1
10.6
3
3.9
19.3
16.4
16.0
10.0
4.1
0
0
0
7.6
7.7
4
3.7
17.7
13.3
17.3
14.2
3.9
0
0
0
1.5
7.2
5
5.0
21.6
17.8
18.4
15.8
3.4
0
0
0
6.1
8.8
6
7.0
8.8
10.9
9.9
9.4
8.9
8.9
10.5
12.7
8.8
9.6
TABLE 11
AVERAGE COLIFORM (MPN/100 ml x 1CP) DENSITIES AND PERCENT REDUCTIONS
July 1958
August
September
October
November
December
January 1959
February
March
April
10 Mb. Av.
% Reduction
Cell
Raw
43,000
45,825
172,000
361,500
277,250
45,825
317,666
205,333
17,200
18,866
150,446
1
3.6
16.4
7.6
38.6
24.9
24.9
59.6
76.3
30.2
31.7
31.4
99.98
2
4.3
1.6
0.59
1.5
2.7
2.5
4.7
17.2
17.2
4.3
5.7
99.99
3
43.0
5.5
6.0
16.5
37.4
37.4
30.1
59.6
59.6
31.7
32.7
99.98
4
0.93
2.3
4.06
5.9
16.4
13.3
18.8
48.4
46.8
59.7
21.7
99.99
5
4.3
4.7
5.9
26.5
5.6
9.5
30.1
18.9
17.2
43.0
16.6
99.99
6
___
4.7
2.9
8.0
4.7
5.5
5.9
17.2
4.3
5.9
6.6
99.99
TABLE 12
AVERAGE PHYTOPLANKTON DENSITY (PPM BY VOLUME)
August 1958
September
October
November
December
January 1959
February
March
April
August-April
Cell 1
5,454
3,122
1,735
772
390
253
172
883
3,603
1,851
Cell 2
972
1,976
16,113
1,434
875
527
111
2,038
3,134
3,658
Cell 3
4,553
6,712
2,719
2,930
974
386
120
1,752
2,053
2,573
Cell 4
1,656
3,857
3,152
703
374
169
39
613
341
1,542
Cell 5
5,726
4,497
1,971
3,333
1,005
190
12
534
4,879
2,532
Cell 6
2,559
3,693
1,752
665
930
702
518
2,760
3,051
1,841
26
-------
PHYSICAL FEATURES
Temperature
Average monthly surface temperatures
(Table 13) differed but little from cell to
cell. Although it cannot be assumed that
some variations did not result from dif-
ferences in time of measurement, it ap-
pears that raw sewage kept ponds slightly
warmer in winter than did effluent from
primary units. During other season, tem-
perature was more directly controlled by
weather conditions.
Vertical series of temperature readings
were made upon several dates to check
upon extent of mixing within the ponds.
Measurements were often taken at 6-inch
intervals, and a difference of 1° C over
this distance was assumed to indicate
separate water layers. This procedure
appeared conservative in view of the char-
acteristic decline of 1° C per meter in
thermoclines of lakes and reservoirs.
Chemical features sometimes indicated
that water layers were not as distinct and
separate as suggested by temperature
differences, but it soon became apparent
TABLE 13
AVERAGE SURFACE TEMPERATURES °C
July 1958
August
September
October
November
December
January 1959
February
March
April
1
28
31
28
20
12
2
2
5
10
13
2
27
30
28
22
12
1
1
4
9
13
3
28
30
28
21
13
2
3
6
10
14
4
28
31
27
21
12
2
2
5
10
14
5
28
31
27
21
12
2
2
5
10
14
6
27
30
26
23
12
1
1
4
10
14
that photosynthesis was at times possible
for some distance down and its effects
upon water chemistry were similar in
various layers. Upon several occasions
chemical features indicated separate wa-
ter strata. Chemical and thermal aspects
are related in the following section.
STRATIFICATION
Representative vertical measurements
made in Cells 4 and 5 in July, August,
September, October, and November 1958
appear in Table 14. These two cells re-
ceived the same quantity of raw sewage
(28,000 gpd), but Cell 4 was 5 feet deep
and Cell 5, 2 1/2 feet deep. Development
of thermal layers and effects of photo-
synthesis or decomposition-respiration
within individual strata are illustrated.
Layers in each lagoon varied from 6 to
18 inches in thickness. Alkalinity and pH
were most influenced by decomposition in
deeper layers and photosynthetic effects
were most pronounced near the surface.
Photosynthesis, when evident, was always
more intense at the 6-inch depth than at
the surface. In Cell 4, oxygen production
apparently did not occur below 18 inches,
but it was present in deeper layers in Sep-
tember, October, and November. In Cell 5,
photosynthesis often occurred at 30 inches.
It is evident from change in alkalinity con-
centration at the bottom that Cell 4 exper-
ienced a period of complete circulation in
early September, and that Cell 5 was first
mixed sometime between August 4 and 11.
Stratification could have been broken up at
other times between sampling dates. Com-
plete circulation evidently promoted better
light penetration in Cell 5 and its entire
liquid depth was thereafter brought under
the influence of photosynthesis and aerobic
activities. In Cell 4, photosynthesis did not
extend as deeply and oxygen reached lower
27
-------
TABLE lit
July 8
11:00 a.m.
Aug. 4
2:00 p.m.
Aug. 11
9:15 a.m.
Aug. 19
12:30 p.m.
Sept. 8
9:20 a.m.
Sept. 18
2:30 p.m.
Oct. 1
2:30 p.m.
Nov. 27
2:00 p.m.
Cell
Depth
0
6"
12"
18"
24"
0
6"
12"
18"
54"
0
6"
18"
36"
60"
0
6"
18"
36"
60"
0
18"
60"
0
6"
12"
18"
24"
36"
60"
0
24"
60"
0
18"
30"
60"
V
4
°C
28.5
28.5
27.0
27.0
25.5
31.0
31.0
28.0
27.0
25.0
30.0
30.0
29.0
28.0
26.0
33.0
33.0
27.0
26.0
25.0
28.5
25.0
22.0
28.0
28.0
27.5
26.0
25.0
25.0
23.0
24.0
21.0;
20.0
8.0
6.0
6.0
4.0
ertica
pH
7.6
7.7
7.4
7.3
7.2
9.8
10.1
8.0
7.2
7.1
9.0
9.0
8.7
7.6
7.1
9.1
9.3
*8.1
7.3
7.1
8.4
8.2
7.1
8.2
8.3
8.1
8.0
7.9
7.7
7.6
9.0
8.4
7.3
8.4
8.1
8.0
7.2
1 Mea
A
C03
0
0
0
0
0
84
94
0
0
0
38
42
28
0
0
46
56
4
0
0
16
4
0
8
10
4
Tr.
0
0
0
42
14
0
14
2
0
0
sureme
Ik.
HC03
220
224
226
232
235
49
38
145
188
192
101
96
110
191
206
95
84
145
201
212
135
148
196
171
170
176
178
183
183
189
123
153
193
156
170
178
196
nts in
02
1.7
3.2
Tr.
0
0
17.8
19.0
7.6
X
18.7 f
19.7
14.6
0
0
20.8
23.6
6.4
0
0
13.2
9.3
0
8.9
8.9
8.5
8.1
6.9
5.4
4.6
19.6
11.3
1.9
10.8
8.7
7.1
1.2
Cells 4 and
July 8
11:00 a.m.
Aug. 4
2:00 p.m.
j
Aug. 11
9:15 a.m.
i
f
"Aug. 19
12:30 p.m.
i
i
f
j
Sept. 18
2:10 p.m.
Sept. 23
10:10 a.m.
5, 195
Cell
Depth
0
6"
12"
18"
24"
0
6"
12"
18"
30"
0
6"
18"
30"
0
6"
18"
30"
0
6"
12"
18"
24"
0
6"
18"
30"
8
5
°C
28.5
28.5
27.0
27.0
25.5
35.0
32.0
30.0
27.0
27.0
31.0
31.0
31.0
28.0
31.0
31.0
29.0
27.5
27.5
27.0
27.0
26.0
25.0
27.0
27.0
26.0
25.0
pH
7.1
7.1
7.1
7.0
6.8
9.6
9.8
9.3
7.1
7.1
9.0
9.1
9.0
8.6
9.2
9.3
9.0
8.7
9.0
9.1
8.9
8.4
8.1
8.9
8.9
8.8
8.1
All
C03
0
0
0
0
0
78
96
52
0
0
42
42
40
24
50
56
42
26
40
42
36
16
Tr.
36
38
30
4
k.
HC03
226
234
234
237
246
74
54
103
212
224
111
111
114
131
105
99
115
132
110
107
115
134
154
120
118
126
153
°V
0
0
0
0
0
27.4
35.6
17.5
0.6
0
19.0
20.1
19.7
12.4
28.9
29.6
27.2
18.7
18.3
19.6
17.5
10.8
9.3
18.2
18.5
16.3
11.1
28
-------
layers only through mixing of water strata.
Periods of complete circulation did not
coincide with any series of depth measure-
ments but they undoubtedly occurred.
It seems reasonable to assume that com-
plete mixing of a stratified pond will lower
oxygen concentration in surface waters
after anaerobic products are brought up
from near the bottom. No observations
were made during a time of full circulation
in 1958, but some 1959 records clearly
demonstrated loss of oxygen following com-
plete circulation in Cell 4 in August and
September (Table 15). Cell 5 maintained
more complete circulation in August 1959
and did not lose oxygen until the advent of
ice cover. More detailed reports on 1959
studies will appear later.
Examination of Tables 14 and 15 should
indicate upward travel of waste products
in stratified ponds with progressive puri-
fication. Upper layers mask the oxygen-
less condition of the depths, and stratifica-
tion imposes an anaerobic-aerobic series
operation. However, reference to Tables
5, 6, 7, 8, and 11 will indicate no in-
crease in efficiency through this type of
operation, and it involves a constant haz-
ard of odor production with each period of
complete circulation. Greater accumula-
tion of anaerobic products delayed oxygen
recovery after ice melt.
TABLE 15
DEVELOPMENT OF COMPLETE CIRCULATION AND RETURN OF STRATIFICATION
IN CELL 4, 1959 (TEMPERATURE AND 02)
D
e
P
t
h
0"
6"
12"
18"
24"
30"
36"
42"
48"
54"
60"
8/26 8/27 8/28 8/29 8/30 8/31 9/3
°C
31.0
31.0
29.5
28.5
27.5
27.0
26.5
26.0
26.0
—
24.5
°2
13.6
—
__
—
0
0
0
0
0
0
0
°c
27.5
27.5
27.5
27.5
27.5
27.0
26.5
26.0
25.5
25.0
25.0
°2
0.2
0.5
0.5
0
0
0
0
0
0
0
0
°C
28.0
28.0
27.5
27.5
25.5
27.0
27.0
26.5
26.0
25.5
24.5
°2
3.9
2.9
0.3
0
0
0
0
0
0
0
0
°C
29.5
28.5
27.0
26.5
25.5
25.5
25.5
25.5
25.5
25.0
—
02
0
0
0
0
0
0
0
0
0
0
0
°c
28.0
27.5
27.0
25.5
25.5
25.5
25.5
25.5
25.5
25.0
—
°2
0
0
0
0
0
0
0
0
0
0
0
°c
27.5
27.5
27.0
26.5
26.5
26.0
26.0
26.0
25.5
—
—
°2
0
0
0
0
0
0
0
0
0
0
0
°c
30.5
30.0
29.0
27.5
25.5
25.5
25.5
25.5
25.5
—
25.0
°2
9.4
7.2
0.4
0
0
0
0
0
0
0
0
ODORS
Sulfides rose from ponds when oxygen-
less conditions persisted after disappear-
ance of ice cover. Cell 2 returned to an
aerobic state four days after its surface
became open; Cells 1, 3, and 5 required
40 to 41 days; and Cell 4 remained oxygen-
less for 61 days after its ice melted. For
a time in late February and early March,
determination of units with greatest pun-
gency was not possible, as sulfides were
detactable for 550 feet from the general
lagoon area and emanations from all cells
were intermingled. By March 10, a no-
ticeable decline in odor intensity was ap-
parent and it was possible to follow the
strongest sulfide trails to Cell 4. Release
of malodorous gases gradually declined
and Cell 4 had barely detectable odor for
a few days prior to recurrence of oxygen
therein on April 27. Decline in sulfides
with prolonged oxygenless conditions has
been assumed due to a low rate of photo-
synthesis that provides oxygen but in quan-
tities unequal to demands. Oxygen ab-
sorbed from the atmosphere may also react
with sulfide.
Odors did not extend to habitations or
work areas.
29
-------
BOTTOM DEPOSITS
Twenty-seven core samples, nine along
each of three north-south transects at the
1/4, 1/2, and 3/4 points of the east-west
width, were collected in each one-acre
lagoon in May 1959. Terminal samples in
each line were 10 feet from margins and
others were at 20-feet intervals. Cores
and supernatant water (2") were dried in
sampler tubes for 12 hours at 100° C and
stored in aluminum foil wrappings prior to
measurement and study.
Each core (Figure 3) extended about two
inches down into the original compacted
clay bottom. The clay was covered with a
layer of granular silt, and this stratum
was topped by a thin, dark green coating
of algae and organic matter. Details for
each cell follow:
Cell
1
2
3
4
5
Loading ( Lbs .
BOD/Acre/Day)
1957-58
20
40
60
80
100
1958-59
120
*
100
60**
60
Thickness (inches)
Organic Layer
Max
0.125
0.03
0.05
0.02
0.06
MLn.
0.008
0.008
0.008
0.008
0.008
Ave.
0.02
0.01
0.02
0.03
0.02
Silt Layer
Max.
2.25
2.30
2.30
2.40
2.25
MLn.
0.5
0.25
0.75
0.25
0.4
Ave.
0.8
0.9
1.1
0.7
1.1
^Received effluent from Cell 3.
**5' deep.
Average thickness for the five lagoons
was: organic layer 0.02 inch, silt layer
0. 9 inch. Gray discoloration of lagoon
water was common after heavy rains and
it appears that infiltration into sewers was
mainly responsible for the silt deposit,
although dike erosion contributed some
sediment before development of vegetative
cover. Intermittent silting trapped some
organic matter, and these inclusions are
considered responsible for the granular
nature of this bottom layer. The organic
layers largely resulted from algal growth,
in contact with the bottom and suspended
in the lower two inches of water. It was
deemed advisable to include suspended
matter extending up this distance as it
was impossible to distinguish between
suspended and deposited particles. Floe-
culent matter often rose in large clouds
when the bottom was disturbed. However,
it dried to thin layers.
30
-------
Cores were not assumed diagnostic of
all events that had affected the bottoms.
Yet, when Cell 1 was pumped down in Oc-
tober 1959, it was apparent that the core
sampling pattern had given an accurate
picture of the general sedimentation rate.
It missed the small mound of silt at the
orifice and the ridge along the inlet pipe
(Figure 4), but these small areas were the
only noted divergences from the general
pattern. Broader inequalities in the bottom
were left after final grading. Watered
areas remaining in Cell 1 after pumping
occupied essentially the same regions in
which water first accumulated at the start
of filling.
Loss of capacity occasioned by sedimen-
tation of organic matter appears incapable
of producing a criterical condition for a
hundred years or more. Silting is a more
serious matter and will probably result in
a loss of one acre foot per surface acre in
about 25 years.
Marginal and emergent vegetation, when
allowed to remain a few weeks, added to
organic bottom deposits in local areas;
and mowers often allowed grass clippings
to settle to the bottom over an area extend-
ing 2 to 4 feet from the waterline. These
contributions were not included in core
samples, as their presence was assumed
unlikely with proper maintenance.
FIGURE 4 - Bottom of Cell 1, October 1959
Note mound of silt at end and silt ridge along inlet pipe.
31
-------
SUMMARY
This article briefly reviews highlights
of the 1957-58 investigation and presents
1958-59 findings. Operation was changed
in Jane 1958 as follows: Load was in-
creased to 100 and 120 pounds B. O. D. /
acre/day in Cells 3 and 1, respectively;
load to units 4 and 5 was decreased to 60
pounds B. O. D./acre/day; and Cell 2 re-
ceived only effluent from Cell 3. Depth
was increased to 5 feet in Cell 4. Raw
sewage load to Cell 6 fell to 8 pounds
B. O. C. /acre/day, and it continued to re-
ceive effluent from other cells.
Operations in 1958-59 substantiated ear-
lier data in indicating desirability of in-
series operation for realization of highest
quality effluent and greatest assurance of
oxygen production under ice and snow
cover. Efficiencies in removal ot various
sewage components remained high.
Depth increase to 5 feet induced more
prolonged thermal stratification and de-
velopment of thicker anaerobic layers.
The latter increased the likelihood of odor
development as they could promote surface
concentrations or sulfides when mixing
developed with full circulation. Greater
production of anaerobic compounds also
delayed return of oxygen in the spring.
Upward progression of wastes purification
during periods of stratification, and aero-
bic cover then developed, would provide
a simple in-series anaerobic-aerobic
operation. However, a maintenance of this
condition would require protection from
wind with a transparent cover, and it ap-
pears to be slightly less efficient in
B.O. D. and coliform removal then opera-
tion with more constant circulation and
greater aerobic volume.
Bottom studies indicated inconsequential
capacity loss to organic sedimentation.
However, silting orginating in sewer infil-
tration will occasion a loss of one foot in
each cell in 25 years.
REFERENCE
1. Neel, Joe K. , McDermott, J. H. , and
Monday, C. A. , Jr. "Experimental
Lagooning of Raw Sewage. Fayette
Missouri, Experimental Stabilization
Ponds. 1957-58." (To appear in Jour-
nal, Water Pollution Control Federa-
tion. )
32
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STABILIZATION POND RESEARCH AND INSTALLATION EXPERIENCES IN
CALIFORNIA*
by
William J. Oswald**
INTRODUCTION
It is the purpose of this article to cover
the status of stabilization pond utility and
design in California and on the basis of cur-
rent research to attempt to predict the
trend that future pond development will
take. Before entering a discussion of Cali-
fornia ponds it is well to review certain
factors which are common to all ponds,
namely the physical and biological reac-
tions which occur in them, their perform-
ance or waste treatment capability and their
classification. This brief review is drawn,
in part, from a more extensive discussion
of pond design fundamentals presented
elsewhere (6).
Physical and Biological Reactions. A list
of evident physical and biological reactions
in ponds must include with respect to the
liquid, such properties as inflow, evapora-
tion, percolation, overflow, thermal ef-
fects and gas exchanges, and with respect
to organic matter; sedimentation, flotation
biological oxidation, anaerobic acid decom-
position, methane fermentation and photo-
synthesis.
The hydraulic properties of a pond are
important because a hydromass of some
magnitude is essential to sustain and pro-
tect the pond microorganisms from rapid
changes in pH, temperature, gaseous ten-
sion and nutrient concentrations. Creation
of a hydromass, therefore, is a prerequi-
site to establishment of a stable biological
community. Not infrequently in newly acti-
vated ponds the volume of evaporation and
percolation may approach that of the inflow
and the pond contains so little water that
marshy conditions sometimes prevail. Un-
der these conditions opportunist algae such
as Chlamydomonas undergo massive and
useless proliferation, accumulate on the
surface, and some die to become vilely
odorous and to form a breeding place for
gnats and flies. If the volume of inflow suf-
ficiently exceeds evaporation and percola-
tion the pond gains depth and ultimately
comes to equilibrium or overflows. The
quality of this overflow then becomes sig-
nificant from a biological, bacteriological
and public health standpoint. Inasmuch as
both evaporation and percolation are ex-
pressed in inches per day, the hydraulic
load on a pond is conveniently similarly
measured. For example pond 48 inches
deep, operating at a detention period of 12
days, receives an inflow of 48/12 or 4
inches per day. If evaporation and percola-
tion total 1 inch per day, outflow will be 3
inches per day.
The allowable organic load on a pond is
a function of the rate at which the various
biological processes dispose of the load
without nuisance and hence its magnitude is
the sum of all such biological removal
processes. The initial biological process,
acting upon organic matter entering a pond,
is usually biological oxidation. Biological
oxidation is dependent upon the presence of
suitable organisms, and sustained contin-
uity of optimum pH (7 - 9), temperature
15° - 25° C, sufficient time to develop a
stable population, the presence of oxygen
2-10 ppm. and the availability of organic
matter. Of major concern is the availabil-
ity of oxygen for which two sources need
be considered--atmospheric reaeration and
photosynthesis. Without special mixing of
a pond by artificial or natural means at-
mospheric reaeration will introduce less
than 40 Ibs. of oxygen per acre per day
even under anaerobic conditions. A pond
•This research was supported in part by research grant 2601 from the National Institutes of Health, United States Public Health
Service.
"Associate Professor of Sanitary Engineering and Public Health, University of California, Berkeley, California
33
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which operates without nuisance is of
course aerobic and therefore absorbs less
oxygen. Thus atmospheric reaeration con-
tributes very slowly to the oxygen re-
sources of unmixed ponds. In fact, atmos-
pheric oxygen is often excluded by super-
saturation conditions which accompany
vigorous photosynthesis.
It has been shown that under satisfactory
conditions of illumination, temperature
and nutrition, photosynthesis may give rise
to 200 Ibs. of oxygen per acre per day.
Assuming 3.68 calories per mg. of oxygen
and a light conversion efficiency of 5 per-
cent (7) the light energy requirement is
15, 000 calories per liter per day, and in-
tensity attainable in ponds 14 inches deep
in summer and 4 inches deep in winter.
Under present operational conditions these
depths are impractical for many reasons.
For example, under the conditions of oxy-
gen production cited, a pH of 11 may be
reached under which conditions, bacterial
growth and oxygen utilization halt entirely,
and coagulation and precipitation of the en-
tire biomass may follow. A pond 4 feet
deep receiving light equivalent to the
15,000 calories per liter per day cited
above will produce about 50 Ibs. of oxy-
gen per acre per day with an increase
in pH to 9.5. Thus successful pond de-
signs are currently limited to load rates
of 40 to 50 Ibs. of BOD per acre per
day. Extensive mixing facilities would be
required to utilize the maximum photo-
synthetic oxygenation rate of 100 or 200
Ibs. per acre per day because sedimen-
tation maintains the biologically available
organic matter at the pond bottom.
Biological flocculation accompanying
biological oxidation brings about accumu-
lation and sedimentation of most of the
dissolved organic matter introduced into
a pond within 24 hours. Studies have
shown that the mass of this material may
equal, or exceed, the applied BOD load.
Thus, a pond loaded at 40 Ibs. of 5-day
BOD per acre per day will also have
about 40 Ibs. of volatile solids deposited
at the bottom each day. Because of its
concentration and position this material
is no longer subject to aerobic oxidation.
The fate of this organic matter at the
pond bottom is then a function of the con-
ditions existing at the pond bottom when
it arrives.
Four major possibilities exist. First,
the temperature is near 4° C, or if the
pH is below 5. 5, decomposition of the
organic matter is very slow and heavy
accumulations of organic matter become
stored at the pond bottom. Second, if
bottom temperature is high, acid decom-
position occurs, and particularly in high
sulfate waters sulfate reduction may oc-
cur with attendant hydrogen sulfide nui-
sance. The third possibility is methane
fermentation which may be highly desir-
able for BOD removal. Ideally, methane
fermentation requires a pH of 6.8 to 7.2,
an absence of oxygen, relatively high
temperature, available volatile acids, the
essential organisms, and sufficient time
for the process to become established.
Under ideal conditions several hundred
Ibs. of organic matter per acre per day
may be converted to methane. Methane
fermentation is evidenced by widespread
easily visible bubbles of gas rising to the
quiescent pond surface. The normal ratio
is believed to be 10 cubic feet of gas per
pound of BOD destroyed. Acid conditions
and low temperatures may delay or en-
tirely inhibit the onset of methane fer-
mentation, but if fermentation is inprogress,
acid conditions are less likely to occur be-
cause the products of acid decomposition
are rapidly converted to methane. It is be-
lieved that methane fermentation blocks the
occurrence of sulfate reduction, primarily
because it controls the build-up of organic
matter; one essential for sulfate reduction.
Methane fermentation is a desirable proc-
ess for decomposition of settled pond bot-
tom deposits and, once the process is
established, leads to a stable, low nui-
sance pond operation. There is little in-
formation on the rate of accumulation of
stable sludge solids in ponds undergoing
fermentation. At the Concord, California,
ponds sludge accumulation amounted to about
1 or 2 cubic feet per annum per capita. Most
of this deposition was within 200 feet of the
pondinlet, a factwhich demonstrates the
rapid rate of sludge deposition in an active
pond. The fourth possible fate of organic
matter is to bring about its resuspension
by physical means, accompanied by proc-
esses which furnish sufficient oxygen to
permit aerobic decomposition.
Pond Classification. Based upon a rec-
ognition of the importance of several
biological processes it has been pro-
posed that from the treatment standpoint
three major classes of ponds could be
defined--an-aerobic, facultative, and
aerobic (6).
34
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Anaerobic ponds were defined as those
in which the major fraction of the applied
BOD is decomposed through me thane fer-
mentation. Designed to establish condi-
tions which encourage methane fermenta-
tion, these ponds may be as much as 10
feet deep, have a small surface area to
volume ratio and may be loaded in ex-
cess of 400 Ibs. per acre per day. An-
aerobic ponds may be extremely odorous
and, therefore, must be carefully located
with respect to populated areas. Efflu-
ents from anaerobic ponds usually have a
BOD in excess of 200 ppm. and hence
require further treatment before discharge
into a water course. Photosynthetic bac-
teria have been observed to become es-
tablished in anaerobic ponds. These or-
ganisms convert hydrogen sulfide to ele-
mental sulfur and hence aid in the control
of odors. If active sulfide reduction oc-
curs, ponds may be without odor.
The term facultative was proposed for
stabilization ponds most commonly de-
scribed in the literature. Ideally, BOD
removal occurs as a result of both aer-
obic processes occurring in the superna-
tant and anaerobic processes occurring in
the bottom sludge layers. Loadings are
ordinarily confined to 50 Ibs. BOD per
acre and effluents rarely have BOD's in
excess of 30 ppm.
In aerobic ponds organic matter is de-
composed solely through the mechanism
of aerobic oxidation. The ponds are de-
signed with a large surface area to vol-
ume ratio and oxygen is introduced by
mechanical aeration or photosynthetic oxy-
genation. In the former case, provision
is required for sludge removal and in the
latter case, large quantities of algae are
grown and may be removed through sep-
aration as a valuable by-product. If con-
tinuous mechanical movement of the liq-
uid is employed BOD loadings in excess
of 500 Ibs. per acre are possible. If
photosynthetic oxygenation is employed
BOD loadings are 100 to 200 Ibs. per
acre per day. In either case, effluent
BOD levels of 20 to 30 ppm. are obtained.
If algae are separated by flocculation an
effluent BOD of less than 10 ppm. may
be obtained. The amount of algae pro-
duced may be 20 to 30 tons per acre per
year.
CALIFORNIA INSTALLATIONS
History. It is uncertain when and where
ponds were first used in California. With
regard to industrial wastes, the beet
sugar industry which entered the state
near the turn of the century brought with
it the practice of impounding wash and
processing waste waters. Impounding of
sanitary wastes occurred coincidentally. A
small ponding installation at Bitterwater,
San Benito County, California, was con-
structed about 1916 to receive oil pumping
station wastes, waste boiler feed water,
and domestic sewage. Preceded by a sep-
tic tank this pond operated successfullyfor
25 years without nuisance. According to
Gillespie (2) the first municipal disposal
plant utilizing ponds resulted from clogging
of seepage beds at Santa Rosa, California
in 1924. Gillespie's interest greatly accel-
erated the use and acceptance of ponds in
California and throughout the West.
Distribution and Application. Ponds are
now used throughout California and are dis-
tributed more or less uniformly in the in-
termediate population density areas of the
state. There are about 125 (1) municipal
stabilization ponds, perhaps three times as
many industrial waste ponds, and numerous
small pond installations in connection with
niki bases, communication centers, iso-
lated restaurants, motels, and so on.
Installations now exist which process raw
sewage or wastes, screened and commi-
nuted sewage or wastes, primary effluent,
trickling filter effluent, activated sludge
effluent, effluents from prolonged aeration
tanks, imhoff tank effluent and septic tank
effluent.
The ponds receive domestic sewage, beet
sugar waste, fiberboard and plywood manu-
facturing wastes, miscellaneous fruit and
vegetable wastes, vegetable dehydrating or
freezing plant wastes, nut processing
wastes, animal holding pen and feeding pen
wastes; slaughter house, packing house,
poultry processing and reduction plant
wastes; and refinery wastes. As far as is
known milk processing wastes and winery
wastes are not processed in ponds in Cali-
fornia.
35
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Pond Systems. There is endless variation
in the type of pond systems employed in the
numerous installations and communities.
Numbers of ponds in a given system vary
from single ponds to some with a total of
10 ponds. The flow-through patterns for
multiple ponds include series, parallel
and combinations of the two. Many of the
systems can be varied from series to par-
allel. Many systems have anaerobic and
facultative ponds in series.
Types of Ponds. Many California ponds
fall into the general class defined above as
facultative. Other ponds are so shallow or
lightly loaded that they remain aerobic
through most of their depth. Several ponds
are intentionally designed to operate in an
anaerobic condition. A system of 4, 2-acre
facultative ponds, operated in parallel, is
to be found in the 8-acre experimental di-
version system at Woodland, California.
Loaded with raw, comminuted sewage at
the rate of about 50 Ibs. of 5-day BOD per
acre per day, the ponds are anaerobic with
methane production in the bottom deposits
and aerobic with algal growth in the super-
natant. Observed to be entirely nuisance -
free, the ponds discharge no effluent and
have attained an equilibrium depth of about
5 feet under a hydraulic load of 1. 5 inches
per day. Two recurring transcient phe-
nomena periodically modify activity in these
ponds. A periodic lightening from their
characteristic green color usually follows
a period of vigorous algal growth. This
lightening is partially attributed to floccu-
lation of algae accompanying precipitation
of magnesium hydroxide and other salts
under conditions of high pH and warm tem-
peratures which typify periods of vigorous
algal growth. Following precipitation a
sharp decrease in dissolved oxygen is ob-
served accenting the importance of photo-
synthetic oxygenation in such ponds. A
second phenomena is recurrent infestation
with "shrimps" and rotifers which also
bring about precipitation of the algae and a
lowering of the dissolved oxygen. Accord-
ing to Hiatt (3) dosage of the pond-s with 1 -
2 ppm. of "Dibrom 8" (Ortho) has proved
effective in controlling Daphnia at Wood-
land.
An interesting anaerobic stabilization
pond is located at the Marks Reduction
Plant, Woodland, California. Reported
previously (6) this pond receives a summer
BOD load of about 700 Ibs. per acre per
day and a hydraulic load of 2 inches per
day. The effluent is discharged into a sec-
ondary pond where it leaches into the soil.
The primary pond receives combined re-
duction plant waste and condenser water
having a BOD of 1, 000 to 1, 600 ppm. The
primary pond effluent has a BOD of about
200 ppm. The supernatant BOD in the sec-
ondary pond is about 50 ppm. Wastes in the
primary pond undergo heavy methane fer-
mentation. The pond's surface is deep pink
with Thiopedia. The secondary pond is
aerobic at its surface and deep green in
color with Euglena. BOD removal in each
pond is about 75 to 80 percent and over-all
BOD removal is in excess of 90 per cent.
Odors from the primary pond are largely
controlled by the Thiopedia which utilize
hydrosulfide. The secondary pond is odor-
less.
No prototype aerobic (high rate) ponds
are to be found in California. Small scale
pilot plant units, 0.01 acres, have been in
operation at the University of California
Field Station for a number of years and are
believed to have amply demonstrated the
utility of this process. These units receive
3 to 6 inches of hydraulic load and 100 to
200 Ibs. of BOD load per acre per day.
BOD Loadings. Most California ponds are
designed for BOD loads of 40 to 50 Ibs. per
acre per day but many exceptions exist.
The lightest pond loading thus far encount-
ered is at the U. S. Army Communications
Center, Davis, California. About 3 feet
deep in adobe soil, the pond has a detention
period in excess of 60 days and a BOD
loading of about 10 to 15 Ibs. per acre per
day. The pond is preceded by a conven-
tional septic tank and is followed by a sec-
ondary pond which is fenced separately
from the primary pond and serves as a
watering place for several dozen sheep used
to control vegetation among the radio an-
tenna masts.
The most heavily loaded industrial waste
pond is that described above at the Marks
Reduction Plant. The most heavily loaded
domestic waste pond in California is the
primary pond at Concord. This primary
pond has a flow-through channel about 1
mile long constructed of redwood baffles
and has aggregate area of 14 acres. Its
loading is about 250 Ibs. per acre per day.
Although able to sustain this load and re-
main odor-free in summer the pond "fails"
and becomes odorous in winter. "Failure",
however, merely means that hydrogen-
36
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sulfide odors are excessive at a nearby
shopping center. Even during "failure" the
pond discharges an effluent to the secondary
pond with a BOD less than 70 ppm. The
secondary pond has an area of about 15
acres and also is arranged by means of
baffles for flow-through. This pond dis-
charges an effluent BOD of about 30 ppm.
to Walnut Creek. Recirculation from sec-
ondary to primary ponds is not possible
under current design, but new construction
will provide this feature which is strongly
indicated under these circumstances.
Pond Sizes. In physical size the vegetable
processing waste lagoons are largest.
Examples are the Spreckles sugar waste
lagoons, Woodland, 400 acres in several
ponds; municipal and cannery waste facul-
tative lagoon, Stockton, 200 acres in a
single pond; and the municipal and cannery
waste lagoons, Davis, about 100 acres in
10 ponds. Of the municipal waste ponds one
of the largest is that at Chico in which,
since no effluent is permitted in the re-
ceiving stream, evaporation and percola-
tion must consume the entire sewage flow.
The Chico ponds have an aggregate area of
103 acres, serving a population of 15,000.
Following primary treatment, BOD loading
on these ponds is about 1,200 Ibs. per day.
About one -third of the pond area is farmed
each year, the farmed acreas being ro-
tated; a feature which greatly improves
percolation. Levees on a gentle alope of 8
or 10 to 1 permit cultivation of the entire
pond area.
Another large municipal pond system is
located at El Centre, California. Consist-
ing of three ponds this system has an ag-
gregate area of 50 acres, serving a popu-
lation of 18,000. Following primary treat-
ment, the BOD load is reported to be about
50 Ibs. per acre per day (5). Relatively
shallow depths, combined with large sized
ponds, have lead to heavy algal growths
which accumulate on the surface and de-
compose. An urgent problem with hydrogen
sulfide odors in this pond's system was
greatly improved as a result of a special
study by Maloney ei al. (4). By excluding
milk waste, hydrogen sulfide odors were
minimized but entirely satisfactory opera-
tion has not been attained to date. In cur-
rent studies the ponds will be operated at
a depth of 6 feet in an effort to overcome
excessive algal growth and perhaps permit
establishment of methane fermentation in
bottom deposits.
The smallest pond installations are those
to be found at road-house inns and individ-
ual homes in remote locations of California.
The disposal system usually consists of a
grease trap, a septic tank, and a pond
sometimes hastily scooped out to replace a
clogged leaching field. Although poorly
maintained, one finds these simple little
ponds green and odor-free.
Pond Depths and Bottom Shape. Excessive
algal growth which leads to formation of
mats, sometimes loosely termed "blue
green algae" is an objectionable condition
which may be prevented by using greater
depth. The current trend in California is
away from shallow depths for facultative
ponds. High rate ponds, which are entirely
dependent upon aerobic decomposition for
waste disposal, must be shallow to permit
photosynthetic oxygenation. Facultative
ponds, however, which are dependent on
both aerobic and anaerobic processes,
should be designed to permit the occurrence
of bottom conditions favorable to methane
fermentation. Thus depths of 5 to 6 feet are
implied. Anaerobic lagoons which depend
almost entirely upon digestion for disposal
have been designed with depths of 10 or 12
feet.
In a trend away from uniform depths sev-
eral recently designed California ponds,
such as those at Vacaville, are constructed
with a gentle bottom slope leading to a
drain. Stone (8) has recently described a
pond with a center well which gives the
pond a small collective area for low flow
conditions.
Levee Slopes and Protection. A great vari-
ety of levee cross sections are to be found.
The flattest levees known to the author are
those at Chico, noted previously, with side
slopes of about 10 to 1. No unusual opera-
tional problems have resulted from this ex-
tremely stable cross section. At the other
extreme the City of Concord, pressed for
area, has shavedits wellcompactedperiph-
eral levees to slopes of less than 2 to 1
and abandoned internal levees entirely in
favor of redwood fences, or baffles, used
as flow guides. Experience has shown that
care must be exercised to maintain approx-
imately equal depths on either side of these
fences to prevent failure.
A greater degree of levee protection
from wave erosion is afforded by maintain-
ing gentle levee slopes than by heavy com-
37
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paction. Rigid compaction specifications
add greatly to the cost of pond construction.
//ind damage is decreased by decreasing
pond size but even 1 or 2-acre ponds will
suffer erosion of steep, carelessly com-
pacted banks during strong winds. Linings
have been used to protect steep levees.
Special bank protection installations are
to be found at a number of places. Stockton
has placed a coat of 6 inches to 8 inches
riprap on its inner levee face. At El Centre
all levees are lined with one-half inch
prefabricated asphalt panels. Davis has
complete asphalt caps on some levees with
gunite side slopes. Both the riprap and
asphalt panels cost about 30 cents per
square foot in place . Cost data is not avail-
able on the concrete liners. At Lakeport,
California, Trotter controlled excessive
seepage with local clay spread and com-
pacted over the entire pond bottom (9). The
University of California's pilot stabiliza-
tion pond at Concord was partially lined
with 6 mil polyethylene. There are no re-
ported cases of ponds completely lined
with more expensive materials.
Inlet and Outlet Structure. Inlet structures
have mainly consisted of simple risers lo-
cated along one side, or in the center, of
the pond. Several consulting engineers have
installed inlets designed to discharge a
horizontal tangential jet of sewage which
appears to give rise to gentle sustained
currents in the ponds. No special benefits
have been observed to result from either
jet type or riser type influent structures.
Limited comparable experience has shown
that the Woodland ponds, with submerged
vertical central inlets, developed methane
fermentation more quickly than did the
Concord ponds which are equipped with
tangential jet inlets. However, unknown
factors other than inlet design could have
produced this result.
Outlet structures are frequently simple
wooden boxes, or corrugated metal cul-
verts, placed in the levee at an invert
height, corresponding to a selected depth.
Vertical risers, built of metal or concrete
and having flash boards with which to con-
trol depth, are commonly used. A modifi-
cation of this type of outlet is a series of
rings stacked in a ring guide. This latter
device has the advantage of allowing 360°
skimming and has been used on recircula-
tion lines at Concord.
Types of Algae. Observation of algal type
in many California ponds shows that the
major algae are nearly always Chlorella,
Scenedesmus, Euglena or Chlamydomonas.
Ankistrodesmus and various blue-greens
are frequently found but usually do not
dominate. With regard to the four most
common algae, Chlamydomonas is the least
desirable, for although it can grow with ex-
plosive speed it spreads over pond sur-
faces, shuts out light, and accumulates in
corners where it decomposes with vile
odors. In Richmond, Euglena viridis has
also been observed to form surface scums.
FUTURE DEVELOPMENTS IN
CALIFORNIA PONDS
Currently the use of facultative ponds is
increasing in California. As conventional
municipal pond installations become more
heavily loaded there will be a tendency in
land short areas to undertake processes
which will make more efficient us"e of avail-
able land. Under these conditions the facul-
tative pond may not survive. It seems
doubtful, however, that there will be a
complete return to trickling filters and ac-
tivated sludge plants since these processes,
although they meet current state standards,
produce, rather than remove, fertility
elements. Regardless of their low BOD and
bacteriological purity, effluents from ac-
tivated sludge and trickling filter plants are
understood to inevitably produce nuisance
algal blooms of uncontrolled and ever-
increasing magnitude in inland receiving
waters. It is therefore expected that addi-
tional state standards for water pollution
control will be forthcoming and that efflu-
ents which contain fertility elements willbe
judiciously excluded from receiving waters
which have no discharge to the sea. Thus
new processes must be developed which
will not only remove BOD and decrease
bacterial content, but also strip away am-
monia, carbonate, phosphate, and other
fertility compounds.
California's new inland reservoirs such
as Turlock, Berryessa or Nacimiento are
undergoing explosive development of popu-
lation and recreational facilities. Sewage
effluents, seepage pit effluents, and efflu-
ents from leaching fields, will inevitably
carry fertility elements into these reser-
voirs in increasing amounts. Successive
38
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crops of algae will integrate these nutrients
and bring about accelerated eutrophication.
A large measure of the enormous recrea-
tional value of these reservoirs will even-
tually be lost, due to excessive algal
growth. A sewage disposal process is re-
quired which will prevent this. The only
process which appears economical for this
purpose today is the high rate photosyn-
thetic oxygenation pond.
Research is now underway to develop
small pond installations for isolated areas
which will remove fertility elements and
dissipate or reclaim them. The best hope
seems to be lined, series operated ponds,
from which the tertiary effluents may be
used for spray irrigation of harvested
crops, for fish ponds, or for beautification
ponds and fountains.
cause of their convenience as well as low
construction and maintenance costs.
It is hoped that eventually inland Califor-
nia communities will undertake to utilize
aerobic high rate algae ponds for all agri-
cultural and domestic wastes, moving
eventually into production and sale of algae
and reclaimed water. Under these condi-
tions we may look for algae to become a
basic raw material, comparable to lumber
or corn; a source of industrial and agricul-
tural chemicals and foods of many kinds.
SUMMARY
This article reviews the history, distri-
bution and current application of stabiliza-
tion ponds in California with emphasis on
special design characteristics in specific
installations.
In the industrial and agricultural waste
field, California is continuing a vigorous
research program for reclamation of an
ever larger fraction of these wastes for
useful purposes. But before this goal is
achieved, it is probable that'anaerobic
ponds will be used to a greater extent be-
Fundamental reactions occurring in
ponds, pond classifications and pond per-
formances are described and discussed.
Current research and development and
prospects for future pond applications in
California are outlined.
REFERENCES
1. Cornish, A., and Ward, Paul, California State Health Department, Berkeley. Pri-
vate Communication (I960).
2. Gillespie, C. G. "Oxidation Ponds in California, " Sewage Works Journal, 16, 740,
(1944).
3. Hiatt, A. L. , City Engineer, City of Woodland, Private Communication (I960).
4. Maloney, T. E., Bartsch, A. F. , et al. "Study of Experimental Sewage Stabilization
Ponds at El Centre, California, " U. S. Department of Health, Education, and
Welfare, Public Health Service, Robert A. Taft Sanitary Engineering Center,
Cincinnati, Ohio, (1959).
5. McKlintock, Len C. , City Manager, City of El Centro, Private Communication,
(I960).
6. Oswald, W. J. "Fundamental Factors in Stabilization Pond Design," No. 44, Confer-
ence on Biological Waste Treatment, Manhattan College, New York (I960).
7. Oswald, W. J. "Light Conversion Efficiency of Algae Grown in Sewage, " Journal of
the Sanitary Engineering Division, Proceedings of the American Society of Civil
Engineers, 86, SA4, 1, 71-95. (I960).
8. Stone, Ralph, "Waste Stabilization Basins for a District Sewage Treatment Plant, "
Civil Engineering, 30, 3, 158-159, (i960).
9. Trotter, Roy M. , and Associates, Consulting Engineers, Berkeley, Private Com-
munication (I960).
39
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STUDY OF THE PERFORMANCE OF A SEWAGE STABILIZATION POND
AT FARMVILLE, VIRGINIA
By
C. E. Cooley, and R. R. Jennings*
INTRODUCTION
Stream pollution control in Virginia
dates from July 1, 1946, when the State
Water Control Law became effective. Soon
afterward a small but determined staff be-
gan work on this very complex problem.
The first job was to notify all communities
that discharged raw sewage into State
waters that they should formulate pollution
abatement programs in accordance with the
Law.
The Town of Farmville is one of the
communities that was so notified. It has a
population of about 5, 000 and lies in an
agricultural belt in south central Virginia.
There is little industry in the area, but a
college with a student population of approx-
imately 1,200 contributes to the Town's
economy.
The Town had retained a consultant who
estimated the cost of constructing a sewage
collection system and a "conventional"
primary treatment plant to be something
over 1/2 million dollars. This was not
considered economically feasible by the
Town fathers. Starting in 1947 they were
requested periodically to appear before the
State Water Control Board, which adminis-
ters the Law, to explain why the Board's
requirements had not been met. The case
continued to drag until finally, in the latter
part of 1956, the Town advanced the pro-
posal to use lagoons, or stabilization
ponds, to treat the sewage.
It was finally agreed, after conferences
and meetings between representatives of
the Town, the State Health Department,
and members of the Board's staff, that the
Town would use a lagoon to treat the sew-
age from a portion of the town.
Lagoons had been used in Virginia for a
number of years successfully to treat in-
dustrial wastes from textile plants, can-
neries, and slaughter houses. They had not
been used for treating sewage, however,
this being the first such installation pro-
posed.
The Town therefore agreed to construct
the proposed lagoon in such a way that the
Board could most expeditiously observe
and study its performance. After many de-
lays, final plans were drawn and construc-
tion was completed. Finally, on November
21, 1958, raw sewage was pumped to the
lagoons for the first time.
SCOPE OF THE STUDY
While planning and construction was
underway, the staff was in the process of
determining the scope of its proposed
study. Considerable data was available re-
garding physical design of ponds, so the
principal objective was to determine the
maximum possible B.O.D. loading which
could be used in this climate. However, we
decided that we would collect as much data
relating to their performance as possible,
within the limitations of personnel, equip-
ment, time and money available. In this
connection, we are especially grateful to
personnel of the U.S.P.H. S. , who gave us
much advice and encouragement in getting
our study program set up and moving.
Their help, stemming from experience,
saved us a great many headaches, but not
all of them.
Automatic equipment was installed to
collect all samples, both of raw sewage
and effluents, for chemical analyses. Man-
ually collected samples were used for
bacteriological and biological analyses.
Engineer and Biologist respectively of State Water Control Board, Richmond, Va.
41
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From previous studies by the
U.S.P.H.S. and other states it was appar-
ent that physical features such as sunlight,
rain, wind, and other natural conditions
play an important role in the successful
operation of sewage lagoons. Therefore,
automatic recording equipment was set up
at the ponds to obtain data regarding solar
radiation (sunlight), barometric pressure,
relative humidity, air temperature, and
precipitation. Apparatus was set up to
measure the rate of evaporation. Although
there was no recording equipment for wind
velocity and direction, frequent visual ob-
servations of indicating meters are made.
We had intended to install Canwisher elec-
trodes in the ponds to measure and record
dissolved oxygen, but we were unable to
get the necessary equipment set up in time.
DESCRIPTION AND LOADING
The Town agreed to construct the lagoon
with three cells of identical size. In the
remainder of this paper they will be re-
ferred to as ponds A, B, and C, as shown
in Figure 3. Statistics on the ponds are
given in Table 16. Depthhas beenmaintained
at 3 feet, although the outlet structures
TABLE 16
Size and Volume of Ponds
Size of each pond, acres
Size of each pond, square feet
Depth, feet
Capacity, cubic feet
Capacity, gallons
60,984
3
182,952
1,372,140
are designed so the depth may be varied
between 3 and 5 feet.
The 1/6, 1/3, and 1/2 volume split was
in effect from November 1958, when the
ponds started operating, until September
5, 1959. On the latter date 1/4 of the
volume was put into Ponds A and B in
series, and 3/4 to C. On December 15,
1959, all flow was diverted to Pond A, in
series with B and C.
The sewage splitter compartment*, for
the first 7 months of this study, was so
arranged that ponds A, B, and C received
1/6, 1/3, and 1/2 of the raw sewage flow,
respectively, for anticipated B. O. D, load-
ings of 20, 40, and 60 Ib. per acre per
day, or a population equivalent of 120,
240, and 360 persons per day, respec-
tively. However, the volume of the raw
sewage did not come up to that expected
from preliminary studies, averaging only
62, 660 gpd to the ponds, about half that
originally expected. While B. O. D. con-
centration was in the expected range, the
total load averaged only 90 Ib. per day,
also about half that expected. Table 17
shows the various expected and actual
load arrangements.
Table 18 shows the actual B.O.D. load
in pounds per acre per day and in terms of
equivalent population.
•The splitter compartment consists of a cylindrical com-
partment 6 ft. in diameter and 1 1/2 ft. high. The incoming
sewer line rises 1 1/4 ft. vertically into the center of the
compartment. Three (or more) gates may be dropped into the
annular space between the riser and the outer wall of the com-
partment to proportion the flow to the three ponds.
42
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,-- ** / L I. Ł SEWAGE LAGOONS
FIGURE 3
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TABLE 18
B.O.D. Load
Pond A ( 1/6 load )
B ( 1/3 load )
C (1/2 load)
Pond A ( 1/4 load )
B (series with A)
C (3/4 load)
Pond A (Total load) . ...
B.O.D., Lb. per Acre
per Day
11
21
32
16
48
64
Equivalent Population
per Acre per Day
67
126
193
96
290
386
CHEMICAL AND BACTERIOLOGICAL
EXAMINATION
Sampling
For chemical analyses, samples of the in-
fluent and final effluents from the ponds
•were taken with automatic samplers.
During the first six months of this study
(February to August, 1959) composite sam-
ples were taken every 12 hours, around the
clock, of the raw sewage and of the final
effluent from each pond. From August
through October 1959 samples from the
same sources were composited every 24
hours.
Samples were analyzed in a Water Control
Board trailer laboratory stationed at Farm-
ville. This trailer was equipped to make all
necessary chemical and biological analysis.
Chemical analyses made were pH, alka-
linity, B.O.D., settleable solids total
solids, total solids, suspended solids,
ammonia, nitrite, mitrate, sulfate, phos-
phate and chloride.
Results of Chemical Analyses
B.O.D. B.O.D. of the raw waste to the
three ponds fluctuated a great
deal. We believe that part of the
variation is due to the fact that a hospital
which is connected to this system period-
ically discharges some type of toxic waste.
We have not made a study to identify this
waste, but we hope to do so.
There was no great degree of difference in
the amount of B.O.D. reduction in each of
the ponds. Changing the flow arrangement
on September 5, 1959 so that pond C re-
ceived what could be considered a shock
load by increasing it by 1/4, apparently
did not affect the degree of B.O.D. re-
duction.
On the basis of the results of the above
loading it was decided, on December 15,
1959, to give pond A, which received 1/4
the total flow at that time, a severe shock
load by increasing it by 3/4, that is, to
receive all of the raw sewage flow. There
was no apparent adverse effect, as shown
by a number of surveys made since that
time.
The overall average B. O.D. reduction for
the period from March 1959 through October
1959 was 80% in each pond. This same
degree of treatment is now being accom-
plished by Pond A with a population equivalent
of almost 400 persons per acre per day.
There is little additional B.O.D. reduction
in Ponds B and C, in series with A.
Percentages of B.O.D. reduction cited
above are based on the concentration of
B.O.D. in ppm. When considered on the
basis of a pounds per day B.O.D. load in
the raw sewage and in the final effluents
leaving the ponds, the indications are that
the efficiency will be higher. This is prob-
ably due to seepage and other losses within
the system making the amount of liquid
being discharged from the ponds less than
the amount which they receive.
45
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Ammonia The overall average ammonia
reduction in the 3 ponds for the
entire period has been 80%. As
in the case of the B.O. D. , ammonia in the
raw sewage had a fairly wide range of con-
centration, while concentration in the final
effluents from the 3 ponds was, for all
practical purposes, the same.
There was considerable variation between
the 3 ponds in percentage reduction of
ammonia during the early period of opera-
tion, but during the late spring and early
summer the same pattern of concentration
is shown in the final effluents from the 3
ponds. However, since the flow arrange-
ment was changed on December 15, 1959,
for Pond A to receive the total load, we are
experiencing an average reduction of only
about 65%. Pond B, in series with A, adds
22 days retention time, and gives an addi-
tional 30% removal for a total reduction of
95%. Pond C adds another 22 days reten-
tion time but apparently accomplishes no
further reduction of the ammonia.
Nitrates There was very little nitrification
in the ponds .
Sulfates The sulfate concentration, as can
be seen in Figure 5, is highly var-
iable and does not show any signi-
ficant increase or reduction. Analysis of
the treated drinking water at Farmville
also indicates a variable sulfate concentra-
tion and does not follow any definite pattern
of concentration.
Orthophosphates Orthophosphates show an
apparent reduction within
the ponds; the greater re-
duction occurring with the least load.
Chlorides Although the data is not shown,
we have found that there is no
significant increase or decrease
of chloride concentration within the ponds.
P.O. and pH P.O. and pH analyses were
made on samples of the final
effluents during a number of
24-hour surveys. These samples were col-
lected every hour during any given 24-hour
survey. In general, the results tend to fol-
low the typical diurnal variation of both
D.O. and pH within the ponds. However,
some results do not show the typical vari-
ation. For example, we have experienced
a high D.O. at night when we would expect
it to be very low, or at least on a decrease.
There is no apparent explanation at this
time for this non-typical variation.
We have made a few preliminary studies on
the D.O. concentrations in the ponds prop-
er. Our results, to date show that there is
a difference in concentration at the various
sampling stations established for this pur-
pose. We hope to make further studies along
this line.
Results of Bacteriological Analyses
Coliform reduction was 99% for at least
50% of the time and 90% or more for 99% of
the time. MPN of coliform organisms in
the raw sewage ranged from 4, 000, 000 to
110,000,000 plus.
BIOLOGICAL EXAMINATION
Introduction
This biological work covers only the
microscopic phytoplankton and the aquatic
insects which inhabit the Farmville stabili-
zation ponds. To avoid confusion regarding
which organisms comprise the phytoplank-
ton and which comprise the zooplankton, all
those planktonic forms of life which are
autotrophic are considered as belonging to
the group of organisms known as Algae.
Also to further simplify the classification
of the Algae, the organisms as herein re-
ported are broken down into three major
groups, as follows:
Green Algae - Bear chromatophores,
usually store their food in the form of
starch, usually possess pyrenoids, and do
not possess flagella in the adult stage. The
diatoms are included within this group,
although they do not store starch.
Bluegreen Algae - Do not bear chroma-
tophores, the pigment being distributed
throughout the cytoplasm; do not store their
food in the form of starch; pyrenoids are
lacking; and do not possess flagella.
The Flagellates - Possess flagella during
the adult stage of their life cycle.
Technical Methods
Sampling From May 1959 through July 1959
all samples collected for biolog-
ical determinations •were made on
46
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the final effluents of the three ponds. This
was done on the assumption that an equal
distribution of organisms existed. Early in
the study only one final effluent sample per
pond was collected for any particular 24-
hour period, but in some cases the time of
collection differed.
To ascertain if we were obtaining a repre-
sentative phytoplanktonic flora, samples
were collected of the final effluents at dawn,
midday, dusk, and midnight. The results
indicated that not only were different genera
discharged during the periods in question
but also that their concentrations varied.
Sampling stations were then selected in the
ponds proper. Results showed an unequal
distribution of genera and numbers within
genera. Therefore, from August 1959
through December 1959, samples were col-
lected in each pond proper, using a Foerst
stream sampler. The samples thus col-
lected, contained organisms from the sur-
face down to a depth of 18". Four stations
were selected in each pond. The above
method, we believe, has given us a more
representative picture of the flora in ques-
tion.
The genera and the number of genera as
herein reported are the total different gen-
era as found at the four stations. The num-
ber of organisms, as reported, are the av-
erages as found at the selected locations.
Enumeration The Palmer Cell, developed
by Dr. C. M. Palmer, was
used in counting the organ-
isms. We believe that the method as put
forth by Dr. Palmer is the most accurate
devised to date.
Correlation of Biological and Chemical
Results
The main purpose of the biological study
was to determine if a correlation existed
between the biological and chemical data.
Tables 19 through 22 set forth the re-
sults of the various possible relationships
that were studied.
TABLE 19
Effect of B.O.D. Loading Upon the Number of Genera and the Total
Number of Organisms
Date
Sept. 4, 1959...
Aug. 28, 1959...
Sept. 18, 1959..
Sept. 4, 1959...
Aug. 28, 1959...
Sept. 4, 1959...
Aug. 28, 1959...
Sept. 18, 1959..
Sept. 11, 1959..
Dec. 14, 1959...
Oct. 20, 1959...
B.O.D. Loading (ibs)
17
17
22
33
34
50
51
65
68
72
73
No. of Genera
25
22
16
18
28
16
12
15
21
12
16
No. of Organisms/ML
do6)
.75
1.09
1.41
0.13
0.28
0.29
1.52
1.37
1.67
6.53
2.66
On the basis of the data we have obtained,
we have not been able to demonstrate a cor-
relation between the number of genera pres-
ent, the total number of organisms and
B.O.D. loading.
47
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TABLE 20
Effect of B.O.D. Loading on the Predominant Genus Present
Date
Sept. 4, 1959
Aug. 28, 1959
Sept. 18, 1959
Sept. 4, 1959
Aug. 28, 1959
Sept. 4 1959
Aug. 28, 1959
Sept. 18, 1959
Sept. 11, 1959
Dec. 14, 1959
Oct. 20, 1959
B.O.D. Loading (its)
17
17
22
33
34
50
51
65
68
72
73
Predominant Genus
There appears to be no correlation be-
tween the loading in terms of B.O.D. and
the predominant genus. It might be noted
that Ankistrodesmus, when not the predom-
inant genus contributed greatly to the total
number of organisms.
TABLE 21
Percent Reduction in B.O.D. Compared to the Predominant Genus
at Different Loadings
Date
Sept. 4, 1959
Aug. 28, 1959
Sept. 18, 1959
Sept. 4, 1959
Aug. 28, 1959
Sept. 4, 1959
Aug. 28, 1959
Sept. 18, 1959
Sept. 11, 1959
Dec. 19, 1959
Oct. 20, 1959
Predominant Genus
Synectocystis
Synectocystis
Ankistrodesmus
Synectocystis
Synectocystis
Synectocystis
Synectocystis
Synectocystis
Merismopedia
Ankistrodesmus
Ankistrodesmus
B.O.D. (Ibs) Load
17
17
22
33
34
50
51
65
68
72
73
Percent Reduction
80
79
79
80
78
79
16
78
79
84
49
As in the two previous cases, there ap-
pears to be no correlation between the per-
cent reduction and any particular predom-
inant genus.
48
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TABLE 22
Percent Reduction in B.O.D. Compared to the Number of Genera and the Total
No. of Organisms At Different Load Levels
Date
Sept. 4, 1959
Aug. 28, 1959
Sept. 18, 1959
Sept. 4, 1959
Aug. 28, 1959
Sept. 4, 1959
Aug. 28, 1959
Sept. 18, 1959
Sept. 11, 1959
Dec. 14, 1959
Oct. 20, 1959
B.O.D. (Its)
17
17
22
33
34
50
51
65
68
72
73
No. of
Genera
25
22
16
18
29
16
12
15
21
16
12
No. of
Organ! sms/ML
do6)
0.75
1.09
1.41
0.13
0.28
0.29
1.52
1.37
1.67
2.66
6.53
Percent
Reduction
80
79
79
80
78
79
16
78
79
84
49
Again, as far as we can determine at
this time, there appears to be no correla-
tion of biological and chemical results.
Typical Genera
Below are listed some typical genera found in the Farmville ponds.
GREENS BLUEGREENS FLAGELLATES
Ankistrodesmus
Chlorella
Chlorocooccum
Closterioposis
Coelastrum
Cruglgenia
Golenkinia
Kirchneriella
Micractinium
Mavicular
Nitzschia
Oocystis
Phytoconis
Scenedesmus
Schroderia
Ulothrix
Anabaena
Anacystis
Merismopedia
Oscillatoria
Synectocystis
C hlamydomonas
Chlorogonium
Chrornulina
Cryptomonus
Eudorina
Euglena
Glenodinium
Gonlum
Gyrodinium
Massertia
Pandorina
Phagus
Trachelomonas
Aquatic Insects
The field work incidental to this phase of
the study was conducted by Mr. Jack Lamb,
Entomologist, Virginia State Department
of Health. The data is limited, since the
main objective was to determine the prin-
cipal aquatic insects inhabiting the ponds.
49
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Listed below are the groups found:
Coleoptera
Cyrindae (Whirligig bettles)
Dytscidae (Preddceous Diving Beetles)
Hydrophildae (Water Scavenger Beetles)
Hemiptera
Notonectidae (Back swimmers)
Diptera
Tendlpedidae (Midges)
Cullcidae
Chaoboninae (Phontom Midge)
Cullcinae (True Mosquitoes)
Culex Piplens
Culex Salinarius
Culex Piplens and Culex Salinarius were
not found in the ponds proper, but were
found both in the overflow line and in the
bottom of one of the overflow boxes, when
the discharge ceased due to evaporation.
These creatures were also found inhabiting
the effluent channel and the swampy area
which receives some of the treated waste.
Excluding the mosquitoes, the rest of the
aquatic insects listed above were found in
all three ponds at various concentrations,
some in the effluent ditch, and some in the
swampy area.
GENERAL, OBSERVATIONS
Odor
Since the possibility of odors occurring is
frequently thought of in connection with this
type of treatment, we have paid special
attentionto this aspect of the sewage lagoons .
Daily observations from February through
September 1959, and frequent observations
since September revealed no noticeable
odors at a distance of more than 20 feet
away from the ponds, except for one day,
which was exceptionally hot and humid with
negligible air movement, when odors were
noticeable about 250 feet away.
Ice Cover
We have not experienced any difficulties in
the ponds, either in the way of odors or
treatment, due to icing.
During the two winters (1 958-59 and 1959-60)
that the ponds have been in operation, the
ice cover has existed for only a few con-
secutive days at a time. Since there were
so few days of continuous ice cover, we
have not considered this condition a signif-
icant factor in our studies at Farmville.
The 1958-59 winter was a particularly se-
vere one.
Weather
Although we have voluminous data concern-
ing the various aspects of climatology we
have not yet had the time to correlate it
with treatment within the ponds. We can,
however, confirm the correlation that oth-
ers have reported to exist between the solar
intensity and dissolved oxygen within the
ponds, that is, the greater the solar radi-
ation, the greater is the concentration of
dissolved oxygen that may be expected.
It is not apparent from our D. O. and pH
studies that wind action adds any appre-
ciable amount of oxygen to the ponds them-
selves. During our 24-hour surveys when
there was sufficient wind Lo cause waves on
the ponds, there did not seem to be any
noticeable increase in dissolved oxygen.
This may be due to the fact that the waves
rolled rather than, broke.
CONCLUSIONS
From the results of our studies the State
Department of Health and the staff of the
State Water Control Board have agreed that
sewage lagoons with loadings of 200 per-
sons (33 Ibs. B.O.D.) per acre per day
will be approved. This compares with an
interim figure of 150, based on recommen-
dations by the USPHS and various other
agencies. Any further upward revision will
depend on the evaluation of the data now
50
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being obtained in the current arrangement
of the ponds.
Also, on the basis of these results, the
interim requirement that ponds be located
1/2 mile from municipal limits and 1/4
mile from the nearest residence and habi-
tation have been eliminated, and criteria
used in setting distance requirements for
conventional sewage plants will apply.
Though the coliform organism reduction
was 90 to 99%, this still represents a high
number of organisms being discharged to
the receiving body of water. Chlorination,
and perhaps also means for removing
algae, must be provided where demanded
by the uses of receiving stream.
Up to this point in our study we have not
been able to correlate our biological data
with the chemical analyses. In the future,
after more data has been collected and
compiled, we will again attempt to deter-
mine if a correlation exists between the
biological and chemical aspects of the
study.
Based on our study of the performance
of Farmville, Virginia, sewage stabilization
pond and our previous experiences with
ponds treating industrial wastes, we be-
lieve that this method provides an entirely
satisfactory and economical means for
waste treatment, under conditions where it
may be employed.
We have not had the time to tabulate and
process much of the data that was collec-
ted. When this is done, additional conclu-
sions and observations will undoubtedly be
possible.
51
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SEWAGE LAGOONS IN AUSTRALIA
by C. D. Parker*
1.0 Introduction.
Study of the possibilities of treatment
of sewage in lagoons in Australia by the
Melbourne and Metropolitan Board of Works
goes back over 20 years and large scale ap-
plication of this form of treatment has been
in use there almost fifteen years.
With the amount of study that has been
made of this form of treatment at Melbourne
over the years it is not surprising that Mel-
bourne offers the most extensive develop-
ment of lagoons in Australia.
It is only over the last 5 - 10 years that
there has been any other developments in
Australia of lagoon treatment but now as in
America, interest in the use of lagoon treat-
ment is widespread, a number of installa-
tions have been built and some of the other
larger authorities are now contemplating
this form of treatment for sewage purifi-
cation.
2. 0 Australian installations.
2. 1 Melbourne.
The use of sewage lagoons in Mel-
bourne goes backtwenty four years to 1936
when alarge area of 570 acres was convert-
ed to a huge pond to give finalizing treat-
ment to effluents from grass areas.
To under stand the way in which de-
velopment of sewage lagoons has occurred
in Melbourne, it is desirable to briefly out-
line the methods of purification that have
been used.
The Melbburne sewage system was
constructed in 1893 on the separate princi-
ple and all flow gravitates to Spotswood
Pumping Station 5 miles from the center
of the city where it is at present lifted
through rising mains 2 miles to the head of
an 11" diameter gravity sewer which con-
veys the 110 m.g.d. (U.S.) to the Metro-
politan Farm at Werribee.
The Farm is 27, 000 acres in area
and here the sewage is treated on 12,000
acres of pasture 2, 100 acres of grass fil-
tration area (used in winter) and 1, 100
acres of lagoons.
Prior to the development of la-
goons, sewage was purified in summer by
irrigation over prepared pastures irrigated
one day every 18-21 days and grazed by
some 15, 000 head of cattle and in winter by
continuous surface application to grass
areas, the effluent being taken into shallow
collecting drains at the end of each bay.
Both processes are liable to dis-
turbance by sudden increases in flow.
This is a daily problem with the
natural fluctuation in flow over the 24
hours of the day. It is accentuated by the
fact that the daily peak flows arrive at Wer-
ribee between midnight and 6 a.m. when
distribution has to be made under night
shift conditions.
The problem is further accentuated
by storm flows when the daily flow arriving
at Werribee is increased from 110 to 170
m.g.d. When these flows occur in summer
and the pastures are sodden, it is a prob-
lem to dispose of the water.
In 1939 research into the possibil-
ities of lagoon treatment was initiated using
the installation described in our paper of
1950 (Parker et al S.W.J. 1950). This con-
'Chief Chemist and Bacteriologist, Melbourne and Metropolitan Board of Works, Aust.
53
-------
sisted of a number of ponds with a total
area of some 5 acres. The most important
finding of these earlier investigations was
the greatly increased efficiency achieved by
using a two stage process, the first stage
functioning as an anaerobic lagoon and the
second stage the normal aerobic algal type
lagoon. Other important operational factors
were also established.
The large 570 acre lagoon already
existing was adapted in 1947 to treat settled
sewage in excess of the average daily rate
of flow, over the daily night peak periods
already mentioned. This development was
based on the experimental work published
in 1950. At first a 30 acre semi-landlocked
section served as an anaerobic lagoon but
subsequently the overall capacity was in-
creased by the provision of 50 and then a
further 50 acres of prepared anaerobic la-
goon, in conjunction with the 570 acre aero-
bic area. In 1951, the 115E lagoon of 60
acres, 15 acres anaerobic and 45 acres
aerobic lagoon was built as a prototype ana-
erobic-aerobic installation also to treat
these daily night peak flows. With increas-
ing dkily dry weather flow these units have
increasingly been used for dry weather
flows throughout the day. At present a third
(35-40 m.g.d.) of the total flow is treated
through these lagoons.
With present conditions it is possi-
ble to handle most of the extra storm flows
through these lagoons by loading them below
their maximum capacity under dry weather
conditions and then increasing the flow of
weak sew/age. Thus the Murtcaim lagoon
normally can handle 30 m.g.d. in summer
and this can be increased to 50 m. g. d. for
periods of two to three days.
A number of smaller areas amount-
ing to 200 acres in all have been converted
from fairly useless land areas to lagoons.
In Melbourne we are faced with an
unusual situation in the next twelve months.
The existing Spotswood pumping station is
currently being replaced by a new station
at Brooklyn situated at the head of the ex-
isting gravity sewer toWerribee. The sew-
age will be carried on from Spotswood to
Brooklyn by deep tunnel gravity sewer and
then lifted vertically into the gravity sewer.
The new station will have a capacity of 300
m.g.d. compared with the present capacity
of 170 m.g.d. Consequently as soon as the
new station operates it will, under flood
flow, pump 300m. g. d. to Werribee instead
of the present 170 m.g.d. This sudden in-
crease in flow to be handled represents a
considerable problem.
To cope with it an area of holding
lagoons of over 400 acres (capacity 500 m.
g. ) has already been prepared and this can
be increased if necessary.
Flood flows will then be run into
these units and held until purified. They
also provide some additional capacity for
treating normal daily flows.
At Braeside Treatment Works
lagoons are used in a different way. In
building the original plant to serve an
area at the southeast of the city, lagoons
were provided following the trickling fil-
ters and humus tank. These consisted of
two in series of about 1 acre in area, fol-
lowed by a larger pond of 15 acres. The
description of this installation was given
in our paper (Parker et al, S.I. W. Jour-
nal 1959). With increasing flows these
lagoons have successfully treated effluent
from filters loaded at 1500 galls/c.yd./d
(effluent B.O.D. 70 - 80 p. p. m. ).
When the plant was enlarged to
cope with the present contributory popula-
tion of 27, 000 the same principle was
adopted. The new filters are now loaded
at 850 galls/yd/d. the humus tank effluent
has a B.O.D. 25 - 30 p.p.m. and this
passes through two new lagoons of 3 acres
each before discharging to the original 15
acre pond. In this way B.O.D. is brought
down to 5 - 10 p.p.m. and the algal con-
tent is quite low, the suspended solids
content remaining well below 30 p.p.m.
at all times.
2.2 Kerang.
The lagoon installation here was
built to meet a rather unusual condition
and to treat sewage of unusual constitu-
tion. Kerang is a Victorian country town
with population of 4 - 5,000. It is an irri-
gation area with a ground water level near
the surface. As a result the sewer pipes
are constantly immersed in ground water
and subject to considerable infiltration.
The ground water is extremely saline
containing some 60, 000 p. p.m. total min-
eral solids. The sewage is consequently
highly mineralized and low in B.O.D.
54
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The wooden rising main which
conveyed the sewage to the treatment
plant had become so filled with slime
growth that it was only possible to pump
the flow part way to the treatment plant
and release it into a swamp. Through lack
of use the treatment plant had fallen into
disrepair and when the main was cleared
by lime and chlorine treatment, it was
decided rather than repair the old plant to
treat the sewage in lagoons. During the
time when the sewage was discharged to
the swamp a considerable odour nuisance
existed and this was a further reason for
taking remedial measures.
The lagoon was constructed as
two anaerobic ponds in parallel followed by
a larger aerobic unit. The daily flow was
500, 000 galls/day, the two anaerobic units
were 0.2 acres each and the aerobic unit
2.0 acres. The detention time allowed was
only 16 hours in the anaerobic unit. Oper-
ation of this installation has shown some
rather unexpected results. Presumably
because of the Ligh mineral content, growth
of sulphate reducing vibrios in the anaero-
bic unit has been extraordinarily prolific
in the 16 hours detention there is an in-
crease to 20 - 30 p.p.m. sulphide in the
effluent. This in turn imposes an additional
oxygen demand on the aerobic unit and it is
remarkable that in the 30 hours detention
in the aerobic unit this sulphide is wholly
destroyed and the B.O.D. is reduced to
25 - 30 p.p.m. a. slightly longer detention
in the arm of the swamp to which the ef-
fluent discharges brings the B.O.D. well
below 20 p.p.m. The microbiology of this
installation offers a fascinating field for
study but owing to the distance from Mel-
bourne it has not been possible to do much
about it. Certainly the algal development
in this highly saline lagoon is very differ-
ent from the normal growth.
Probably the most effective way of
dealing with this type of sewage is a single
large aerobic lagoon with recirculation of
effluent to the influent to prevent the devel-
opment of anaerobic conditions.
2. 3 Wangaratta.
Here the domestic sewage from
a town of 5 - 6, 000 together with woollen
mill and rayon weaving mill wastes are
treated in an anaerobic unit of 3 acres with
7 days detention and an aerobic unit of 20
acres with 22 days detention.
The aerobic lagoon is a typical
single unit pond with profuse growth of
Euglena and Trachelomonas, the filtered
B.O.D. is 10-15 p.p.m. It is at present
proposed to subdivide the 20 acre aerobic
pond into a series of small units to be
operated in series to reduce the algal con-
tent of the final effluent.
2. 4 Castlemaine.
Here lagoons are provided after
trickling filters, there is ample detention
and a sparkling clear algal-free effluent
is obtained.
2. 5 Commonwealth Department of
Works.
Has a four lagoon installation, as
tertiary treatment for overloaded filter
plants.
2.6 Others.
A few other country sewage treat-
ment plants have lagoons after secondary
treatment.
3. 0 Operational factors important under
Australian conditions (Melbourne).
Use of sewage lagoons in Australia
falls into three categories.
(a) Anaerobic - aerobic two stage
units for the continuous treatment of dry
weather flow raw sewage.
(b) Holding ponds for intermittent
treatment of storm flows.
(c) Aerobic units for tertiary treatment
after high rate trickling filters.
3.11 Anaerobic units - continuous
treatment.
(a) There is no exact quantitative
data as to whether they should be designed
on an area or volume basis. Probably for
the same volumetric content a shallower
unit would be more effective than a deeper
one.
(b) There is no optimum size as
wave action is unimportant.
(c) With multiple cells these are
more efficient if arranged in parallel.
55
-------
(d) Their microbiological function
is to perform a methane fermentation; pho-
tosynthetic purple sulphur bacteria are
sometimes present but not algae. Sulphides
are formed from sulphate but also de-
stroyed, concentrations are often less in
the effluent than the influent. There should
be a rise of about 0. 5 pH unit through the
ponds.
(e) There is less odour than from
a corresponding area of raw sewage.
(f) With high solids loading there
is some carry-over to aerobic units but no
evidence of failure of anaerobic units due
to solids accumulation. Arrangement of
anaerobic cells in series will minimize this
carry-over. Possibly a sedimentation unit
between anaerobic and aerobic units would
be desirable.
(g) B.O.D. removals found are
summer (70° F) 1200 Ibs/ac/d, winter
(48° F) 350 Ibs/ac/d. Suspended solids are
reduced from 450 p.p.m. to 75 p.p.m.
3. 12 Aerobic units - continuous treat-
ment.
(a) It is desirable to limit the size
of each cell to 10 acres.
(b) Optimum depth is 2 - 3 feet.
(c) Pond Layout influences micro-
biological character of final effluent.
(d) B.O.D. removals are similar
to elsewhere, 60 - 100 Ibs/ac/d.
(e) Optimum ratio between area
of anaerobic and aerobic units is 1 to 5.
(f) Wall construction may be 1 1/2
to 1 protected by concrete or 5 to 1 grassed
or metalled.
3. 2 Holding ponds for storm flow treatment
int e r mitt e ntly.
(a) B.O.D. removal is at same rate as
aerobic ponds operated continuously.
(b) Method of operation is dependent on
hydraulic considerations, e.g. whether
ponds should be held full, empty or half-full
between uses.
(c) Where ponds are to be used infre-
quently deeper ponds are preferable to
shallower units.
3. 3 Aerobic ponds after high rate trickling
filters.
(a) These may be used where complete
odour elimination is necessary to relieve
an overloaded filter plant or deliberately as
a form of economic'high rate treatment.
(b) B.O.D. removals are higher than
for aerobic units treating raw sewage or
anaerobic effluents
(c) The algal content of the effluent is
low.
(d) High coliform removals are
achieved.
4. 0 Research.
Research in Australia on lagoon
treatment is centred at the Melbourne and
Metropolitan Board of Works.
The current program of research
on lagoon treatment in Melbourne includes
the following topics.
(a) The study of the effect of lagoon
layout in relation to hydraulic character-
istics of installations used for intermittent
treatment of weak storm flows.
(b) Effect of various lagoon layouts on
the chemical and microbiological charac-
teristics of aerobic lagoon effluents loaded
at the same over-all rate.
(c) Study of the most effective distri-
bution of loading between high rate filters
and lagoons when used in conjunction, par-
ticularly with regard to the chemical and
microbiological characteristics of the final
effluent.
(d) A comparative study of the micro-
biology of sewage lagoons operated in var-
ious ways.
56
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ECONOMICS OF WASTE STABILIZATION LAGOONS IN REGION VI
By Herbert C. Clare and Daniel J. Weiner*
INTRODUCTION
The wider acceptance of the waste stabi-
lization lagoon in the past decade reflects
satisfaction of a demand by municipalities
for a treatment facility which fulfills low
cost as well as effective treatment re-
quirements. In this period, an increased
use of the lagoon for treatment of raw sew-
age has served to provide sufficient data
to enable water pollution agencies, other
interested agencies and individuals to pro-
vide more realistic fiscal data whenever
the familiar question "How much is it going
to cost?" arises.
Both raw sewage lagoons and conven-
tional treatment plants have their places in
the waste treatment field, and frequently
conventional plants and waste stabilization
lagoons have been utilized in combination
to maintain the quality of water in a re-
ceiving stream.
The collection of extensive data for this
report has been made possible by the pas-
sage of the Federal Water Pollution Con-
trolAct, P. L. 660, 84thCongress, wherein
the U. S. Congress authorized grant funds
for the construction of sewage treatment
works as an integral part of Federal finan-
cial assistance for the prevention and con-
trol of water pollution. The intent of the
Act is to "accelerate local programs of
treatment works construction by providing
an incentive to take action, now to clean up
the waters of the country".
STUDY METHOD
(a) Sampling
The acceleration of community pro-
grams to construct treatment works for the
abatement and control of water pollution is
reflected in some 452 projects, which have
been completed or are in the construction
or final planning phases, in Region VI,
consisting of the states of Iowa, Kansas,
Minnesota, Missouri, Nebraska, North
Dakota and South Dakota. Cost data have
been assembled, and include either the fi-
nal construction costs or the actual con-
tract prices, depending upon the status of
the project. The project design population
equivalents range from 150 to 48, 000.
For this presentation there have been
gathered cost data from the files of 262
engineered treatment plants, which include:
13 primary plants, 81 secondary plants, 8
oxidation ponds (conventional treatment
plants followed by lagoons), and 160 waste
stabilization lagoons otherwise known as
raw sewage lagoons. In Region VI there
has been considerable activity in waste
stabilization lagoon construction, indicated
in Table No. 23.
Resonably accurate cost data are desir-
able, so that they can be used by water
pollution control agencies, consulting engi-
neers, municipal officials, and other agen-
cies and individuals interested in water pol-
lution control as a yardstick to gauge a
municipality's ability to afford a waste
treatment facility. Further, they help pro-
vide guidance in the selection of a particular
type of works tailored to meet specific treat-
ment requirements.
No attempt was made to evaluate differ-
ences in costs due to variations in design
criteria for conventional treatment plants
throughout Region VI. Similarly, there was
no differentiation between lagoon loading
and sizing; single or multiple cells; earth-
work and land costs.
(b) Study Basis
This study was based on a comparison
of hydraulic and organic loading and proj-
ect cost. The loadings were those stated
•Respectively, Regional Program Director and Construction Program Director, Water Supply and Pollution Control Program,
PHS, Region VI, Kansas City, Mo.
57
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TABLE 23
Sewage Treatment Facilities
State
Total
Primaiy
Plants
9
2
1
1
6
1
13
Secondary
Plants
21
24
19
7
10
81
Oxidation
Ponds
8
8
Waste
Stabilization
Lagoons
3
11
3
44
21
52
26
160
by the consulting engineers. Included were
the 20-year design factors, such as popu-
lation and industrial growth. Estimates of
future industrial wastes as presented in
engineering reports were included in the
design population equivalent.
(c) Statistical Method
To present the data statistically in
linear form, the least squares method was
utilized. This method is based upon the law
of chance of random sampling and is de-
signed to make the sum of the squares of
the differences, or residuals, between ob-
served and calculated values a minimum.
The least squares line for a given series
may be obtained through use of a given set
of "normal" equations. The "normal" equa-
tions for a linear equation, y = a + bx, are
as follows:
(1) a + b(Ex) - Ey = 0
~nTT"
(2) a(Ex) + b(Ex2) - (Exy) = 0
The range of data led to a use of the log-
arithmic scales, and "normal" equations
for the linear form of the equation y = axD
were as follows:
(1) a + b(E log x) - E(log y) = 0
(2) a(E log x) + b(E log2 x)
n n
- (E log x log y) = 0
Where Ex = sum of population equivalent
(PE)
= sum of 1000 gpd design flow
Ey = sum of cost of treatment in
$/PE
= sum of hydraulic loading treat-
ed in $1000/mgd
= sum of squares log population
equivalent
= sum of squares log design hy-
draulic loading
E(logx) (log y) = sum of products of the log-
arithms of "x" and "y"
a = constant
b = constant
Data are expressed in current dollar val-
ues for cost of treatment in $/PE and in
$1000/mgd to provide realistic data based
upon current dollar values for use of con-
sulting engineers, municipal officials and
others interested in treatment costs. Com-
parisons with other known methods and in-
dices were considered.
TREATMENT COSTS
Total costs, including land costs, based
upon the total population equivalent to be
treated and the total design flow, are in-
cluded in Table No. 24.
Primary treatment installations would
serve a population equivalent of 186, 760
with a flow of 19.31 mgd, at a cost of
$3,530,830.88.
58
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TABLE 24
Total Design Loadings and Costs
Conventional
plants
Lagoons excluding interceptors
Design
population
equivalent
14,366
41.4,4.66
4,800
291,570
291,570
Design flow
1000 gpd
19,313
36,550
491
28,049
28,049
Total cost
(dollars)
3,530,344.88
14,300,972.01
308,550.32
8,044,830.34
4,919,294.77
Secondary treatment plants cost $14,300,
972.01 and were designed to treat wastes
amounting to 414,466 population equiva-
lents and a flow of 36.55 mgd.
The oxidation pond units were designed
to treat a waste equivalent to 4, 800 per-
sons with a sewage discharge of 0.49 mgd
at a cost of $308,550.32.
The lagoons included in this study have
been designed to serve a population equiv-
alent of 291,570 with a waste discharge of
28.05 mgd. Cost, including intercepting
structures, amounted to $8,044,830.34;
cost without these structures was $4, 919,
295.77.
Population Equivalent- A population equiv-
alent (P.E.) is used to express industrial
wastes and is based upon 0. 167 pounds per
day of 5 day, 20°C. Biochemical Oxygen
Demand (B.O.D.) per person. Inthis man-
ner the organic component of industrial
and domestic -wastes may be expressed in
a common denominator.
Region VI costs are presented in Figures
4, 5, 6, and 7. Figures 4 and 5 show the
total cost for each type of treatment proc-
ess. These are presented on the basis of
design population equivalent and flow. De-
sign flows are expressed in 1,000 gallons
per day to facilitate computation of the
line of best fit. Figures 6 and 7 indicate
the cost in dollars per population equiva-
lent and cost in thousands of dollars per
million gallons of wastes treated daily.
The largest and smallest plant sizes for
each type of treatment facility are indica-
ted by hash marks on the curves.
Tables Nos. 25 and 26 provide additional
cost data and present a comparison of
costs. The upper range in population
equivalent and million gallons per day to
be treated is based upon an extrapolation
of the cost curves. The equation for each
curve is presented in Appendix No. 1 of
this paper.
The tabulations indicate that primary
treatment plants for design population
equivalents of 100, 1,000 and 10,000 may
be population equivalent: $77.91, $40.05
and $20.58; per population equivalent for
secondary treatment works, $127. 30,
$64.83 and $33.02; for oxidation ponds,
$105.20, $53.34 and $27.04; for waste
stabilization lagoons, including interceptor
or outfall structures, $69.90, $34.79 and
$17.32; and for waste stabilization lagoons
without interceptor or outfall structures,
$29.36, $18. 52 and $11. 69, respectively,
All costs include land.
Land Costs
Land costs have been included for all
treatment plant types, to obtain a complete
and equitable comparison.
Land costs for 213 primary, secondary,
raw sewage stabilization lagoon and oxi-
dation pond projects were studied. Data
for 10 primary facilities, 68 secondary
plants, 127 raw sewage lagoons, and 8
oxidationpond installations were reviewed,
and average land costs for each group
were computed in $/PE. The results are
presented in Table No. 27.
Included in this study is a comparison of
conventional treatment plant costs includ-
59
-------
TOTAL COST, $1, 000
* \
\ \\ \
\ Xx \
\ \\ >
60
-------
10
TOTAL COST, $1,000
^r^r~
_J_ I I 1
JJKL
\
\
\
\
\ \
\ \
^ s
V^
\\
\\
O .
5!
•^
I.QQO
\
\
10.000
o
G
W
Ul
CO
O
2
d
>-< 1-3
2 •
61
-------
COST, $/PE
62
-------
COST, $1.000/MGD
63
-------
REGION VI
TABLE 25
Treatment Plant Costs Based Upon Design Population Equivalents
Population
Equivalent
100
1,000
10,000
100,000
Primary
77.91
4-0.05
20.58
10.58
Secondary
1?7 30
6-4.83
33 02
16 82
Oxidation
Ponds
105 ?0
53 34
?7 04
13 71
Lagoons
w/int .
69 90
34 79
17 3?
8 62
Lagoons
w/o int.
pq 36
18 5?
11 69
7 37
TABLE 26
Treatment Plant Costs Based Upon Design Flows
1,000
gpd
10
100
1,000
10,000
Primary
689.30
384.10
214.00
119.20
Secondary
1,468.00
719.00
352.20
172.50
Oxidation
Ponds
1,927.00
458.00
18.90
25.88
Lagoons
w/int .
736.50
355.00
171.90
83.02
Lagoons
w/o int.
296.00
185.00
115.70
72.33
TABLE 27
Land Costs for Treatment Works
Type of plant
Cost
in $/PE
1.25
1.20
3.10
2.30
ing land with waste stabilization lagoon,
construction, land, and interceptor (out-
fall) costs. These costs are actual con-
struction or contract costs and land prices.
Where a lift station and force main is part
of the interceptor (outfall) sewer, this has
been included in the cost of the lagoon
treatment facility.
Another study compares cost of the con-
ventional treatment plant including land
with costs of the lagoon and land, but with-
out the interceptor or outfall structure.
Fees for administrative, legal, engineer-
ing and technical services were not in-
cluded in these costs.
DISCUSSION
One special characteristic of Region VI
is the number of small communities. Cog-
nizance must be taken of the fact that with-
out a reasonable first cost for a treatment
facility and for the operation and mainte-
nance which follows its installation, waste
treatment would be out of financial reach
of a large number of these small commu-
nities.
It is apparent frorrfthe curves in Fig-
ures 4, 5, 6 atid 7 that waste stabilization
lagoons, with or without intercepting or
outfall structures, generally cost less than
primary or secondary treatment facilities.
In Figures 5 and 7 the curves intersect for
plants designed to treat wastes from small
64
-------
communities amounting to-30, 000 gallons
per day. However, the curve for primary
plants is based upon a study of only 13
projects. If the primary curve were based
upon more extensive data, the two curves
might not intersect. Cost curves in Fig-
ures 4 and 6 show that the waste stabiliza-
tion lagoons require a lower initial capital
investment. In these figures, none of the
curves intersect. The change in slope of
the primary plant curve caused by the use
of gauged flows instead of arbitrary flows
for design purposes accounts for the fact
that the curves intersect in Figures 5 and
7 and not in Figures 4 and 6.
The use of lagoons depends largely upon
the feasibility of using available land. De-
velopment of waste stabilization lagoons
as a treatment device may have had an in-
itial setback because of the belief that la-
goon land costs could exceed other financial
benefits, such as low annual operation and
maintenance costs and the initial capital
investment of the structure when com-
pared with other treatment methods.
Experience data have shown that in many
cases the price of land may be fifty per-
cent of the cost of the completed waste
stabilization lagoon, yet the total cost has
been equal to or less than the cost of a
completed secondary treatment works. In
numerous instances land costs could be
double or triple the completed lagoon con-
struction costs before equaling the conven-
tional plant cost.
However, experience has shown that in
addition to providing decided advantages of
a high degree of treatment, low initial cap-
ital investment, and low operation and
maintenance costs, the raw sewage lagoon
possesses a flexible feature, particularly
in areas which are subject to rapid popula-
tion growth. In such cases it has been found
that lagoons may be resited and constructed
downstream and the lagoon land which may
have appreciated in value can then be re-
claimed for housing or industrial site de-
velopment.
In addition to its use as a device for
treating raw sewage, the attractive fea-
tures indicated above lead to consideration
of lagoons to provide a polishing of con-
ventional, pri.mary or secondary treatment
plant effluents.
In some instances it may not be possible
to procure an adequate area for the lagoon
at the plant site, but may be possible to use
a lagoon located at some distance from the
conventional plant. When topography will
not permit use of gravity piping between
the conventional plant and the lagoon (oxi-
dation pond), pumping will be necessary,
and a feasibility cost study will be required.
The study showed that land costs vary
widely and that variations depend largely
upon the location and numerous land uses
as well as intangible human factors.
The data in Tables Nos. 25 and 26 can be
used to compare the approximate cost of
each type of treatment facility. The study
emphasizes the need for compiling more
complete project data. Cost information
resulting from an evaluation of these data
will aid inpreliminary engineering phases.
Adequate records of operation and main-
tenance costs have not been gathered for
waste stabilization lagoons. A limited
amount of data has been assembled for
conventional treatment plants. On the ba-
sis of information supplied in the project
engineering reports of consulting engi-
neers, a wide range exists in the esti-
mates of these expenditures for all types
of waste treatment facilities.
These latitudes in costs are dependent
upon the price in individual local areas for:
Labor, fuel and power, size of plant, the
amount of built-in mechanization, as well
as expenditures for replacement of equip-
ment. The simplicity of lagoon design ob-
viates most of these costs.
Lagoon maintenance seldom requires
more than two cuttings of the dike slope
grass per year. The removal of scum,
grease and floating algae is not generally
a problem. Therefore, this operation does
not require the attention associated with
removal of the same material in conven-
tional treatment plant operation. Seasonal
operation of valves may be required for
multiple cell installations for operation in
parallel or series or where flexible depth
control is exercised for optimum effi-
ciency. Removal of emergent vegetation
may be required periodically and may be
65
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minimized by providing the required liq-
uid depth. Duties at an average conven-
tional plant require similar, but more
concentrated, effort and vigilance. The
average conventional plant with a greater
number of details requires more extensive
attention of a skilled operator.
Estimated operation and maintenance for
waste stabilization lagoons range from
$0. 20 to $1. 00 annually per population
equivalent, and from $1.00 to $4.00 per
population equivalent year for conventional
waste treatment plants.
Additional data are needed for lagoons
serving population equivalents and design
flows in the upper ranges of the graphs.
When obtained, this will enable investiga-
tors to arrive at more reasonable conclu-
sions.
SUMMARY AND CONCLUSIONS
Data presented represent a large number
of sewage treatment facility cost data in
Region VI. Cost data of the varying treat-
ment processes have been.analyzed and the
evaluation of plants cost summarized. The
results should provide a reasonable assist-
ance to water pollution control agencies,
municipalities, consulting engineers and
others interested in water pollution abate-
ment measures.
Waste stabilization lagoons cost less to
construct than other types of waste treat-
ment facilities. Land costs are slightly
higher, but are offset by the lower initial
capitol cost and difference in annual oper-
ating and maintenance cost. In addition,
lagoons provide greater ease of relocation,
possibly with financial benefits due to in-
creased land values.
Lagoons may be used in combination with
conventional treatment works to provide
additional treatment capacity at a lower
cost.
ACKNOWLEDGMENT
Acknowledgment is made of the partici-
pation of Thurman B. Sauls, Assistant
Sanitary Engineer (R), in the preparation
of this paper.
66
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APPENDIX 1
Cost Curve Equations for
Studied Treatment Facilities in Region VI
.70/(P.E.)°-293
0.707
Secondary $/PE = 490.
$l,000/mgd = 2,997. 00/( 1,000 gpd)
Total Cost
Total Cost
Primary $/PE = 294
$l,000/mgd
Total Cost
Total Cost
0.310
= 490.70 (P.E.)
= 2,997.00 (1,000 gpd)
.90/(P.E.)0'289
= 1, 237. 00/( 1,000 gpd)
= 294.90 (P.E.) °-711
0.690
0.245
= 1,237.00 (1,000 gpd)
0.746
Lagoons w/interceptor
0. 303
EQUATIONS
$/PE = 282.80/(P.E.)
$l,000/mgd = 1,525.00/(1, 000 gpd)
Total Cost = 282. 80 (P.E.) °'69?
Total Cost
0.316
0.684
Lagoons w/o interceptor $/PE = 73.73/(P.E.)
= 1,525.00 (1,000 gpd)
0.200
0.204
$l,000/mgd = 473.40/( 1,000 gpd)
Total Cost = 73.73 (P.E.) °-8°°
Total Cost = 473.40 (1,000 gpd)0>°796
Oxidation Ponds
$/PE = 409.30/(P.E.) °'295
$l,000/mgd = 8, 108.00/(1,000 gpd)
Total Cost = 409.30 (P. E.) °'7°5
0.624
Total Cost = 8, 108.00 (1,000 gpd) °'376
Bibliography
Fair, Gordon Maskew, and Geyer, John Charles
Water Supply and Waste Water Disposal. John Wiley and Sons, Inc., New York, (1956)
Howells, D. H. , and Dubois, D. P.
Design Practices and Costs for Small Secondary Sewage Treatment Plants in the Upper
Midwest.
Sewage and Industrial Wastes, Vol. 30, No. 11, November, 1958.
67
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SOME OBSERVATIONS ON THE GROWTH, APPLICATION, AND
OPERATION OF RAW SEWAGE STABILIZATION PONDS
W. W. Towne and W. B. Horning*
INTRODUCTION
To avoid unnecessary repetition of mate-
rial already covered we will present some
general comments relating to the growth,
application, and operation of this method of
sewage treatment. Therefore, we will
briefly discuss: (1) the factors influencing
the growth and use of raw sewage stabili-
zation ponds in the United States; (Z) the
conditions affecting the applicability of this
type of sewage treatment; and (3) some of
the operating problems that have come to
our attention both within the United States
and in foreign countries. In closing we
would like to present some general conclu-
sions that have developed as a result of our
association with the problem over the past
several years and to point out some of the
questions yet to be answered.
It is realized that the stabilization ponds,
oxidation ponds, lagoons, or whatever you
prefer to call them, have been in use in
this country for many years. In fact, they
are probably one of the oldest man-made
sewage treatment devices. Previous to
1948, however, when the first ponds were
constructed at Mattock, North Dakota, the
process had been looked upon as an adjunct
or supplementary treatment process rather
than a complete method of sewage treat-
ment. It is only within the past few years
that ponds have been used extensively in
this capacity. This early phase of the de-
velopment in the Dakotas has been well
documented here by Mr. Svore. Without
question many communities are now enjoy-
ing a higher standard of living and health
protection because of the foresight of these
early investigators. This early apprehen-
sion was extensive and many could not vis-
ualize the application of stabilization ponds
as a complete method of sewage treatment
even in those areas where the facilities had
been used as secondary or tertiary treat-
ment devices and where they had demon-
strated their ability to stabilize organic
matter.
EARLY GROWTH
During the early 1950's then, the process
entered a trial period and those that had
observed the results became more and
more convinced that this system of sewage
treatment definitely did have an area of
application. It was also recognized that
additional scientific information was essen-
tial concerning the factors involved in the
stabilization of organic matter, if rational
design criteria were to be developed. Fur-
ther evidence of this spreading interest
was the resolution adopted by the State and
Territorial Health Officers Conference in
1954 asking the Public Health Service to
investigate this method of treating raw
sewage and to determine the various design
factors, their effectiveness and details of
operation. The Regional Office, here at
Kansas City, had also been following early
developments in the Missouri Basin and in
1954 representatives of that office, the
Robert A. Taft Sanitary Engineering Cen-
ter, and the States of North and South Da-
kota developed plans for a cooperative
study to obtain seasonal operating data
at five different installations in the two
States.
Concurrent with this work other investiga-
tors were conducting research relating to the
performance of oxidation ponds and the fac-
tors affecting the algal-bacterial relation-
ships involved in the stabilization processes.
The University of California has long been the
focal point for this type of research; Gotaas,
Ludwig, Oswald, and associates have
all made outstanding contributions to a bet-
ter understanding of the phenomena in-
'Chief, Field Operations Section, and Biologist, Field Operations Section, respectively, Technical Services Branch, Robert A.
Taft Sanitary Engineering Center, Cincinnati, Ohio.
68
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volved. Herman and Gloyna, at the Univer-
sity of Texas, also were actively engaged
in research on the subject, as were many
others.
While the Public Health Service fully
recognized the importance of this basic re-
search and, in fact, contributed to its sup-
port through research grants, the need to
evaluate the field application of the re-
search findings in many sections of the
country was recognized. The Public Health
Service was zilso interested in developing
an adequate low-cost method of sewage
treatment requiring a minimum of techni-
cal supervision and maintenance. To this
end the major effort of the Public Health
Service has been directed to field observa-
tions and studies.
While these early studies did not develop
mathematical design formula they did point
out general design factors that required
consideration and demonstrated that prop-
erly designed and operated stabilization
ponds would provide a degree of purifica-
tion comparable to that obtained by conven-
tional complete treatment processes and
that the effluent might be discharged in a
similar manner. At the same time it was
fully recognized that like any other sewage
treatment process, stabilization ponds had
advantages and disadvantages and they
should not be considered as a panacea for
all sewage treatment needs, but that their
use deserved to be considered in the eco-
nomic and engineering evaluation of waste
treatment methods. This type of field
evaluation was no doubt instrumental in ob-
taining general acceptance by many regula-
tory agencies.
Another important benefit of these field
evaluations was related to the Construction
Grants Program of the Federal Water Pol-
lution Control Act which got under way late
in 1956. Because our observations and in-
vestigations clearly supported the efficacy
of this type of treatment, the Service felt
justified in approving this method of sew-
age treatment as being eligible for con-
struction grants. During the first two years
of the Construction Grants Program 254
projects in 29 states in which stabilization
ponds was a method of treatment were
approved for Construction Grants. Fifteen
months later, namely as of March 31,
I960, Grant offers had been made on 443
projects in 3,2 states. Some of these were
for stabilization ponds operating either as
secondary or tertiary treatment units.
However, as of May 31 of this year 418
raw sewage stabilization pond projects have
been approved for construction in 27 states.
In addition to these Federal aid projects,
many projects have been constructed with-
out such aid and this type of treatment is
now being used in at least 39 states either
for complete or partial treatment of do-
mestic sewage. This process is also being
used by an increasing number of industries.
Judged by our experience these facilities
have functioned with a minimum of diffi-
culty and complaint other than the usual
problems often associated with placing any
new sewage treatment plant in operation.
Thus, it would appear that the use of stabi-
lization ponds for treating raw municipal
sewage is now beyond the trial period and
we are now approaching the time when our
efforts should probably be directed at re-
fining design criteria so that their applica-
tion can be extended into other areas and
their cost may be further reduced.
APPLICATION OF THE PROCESS
As previously stated, this process is not
a panacea for all sewage treatment prob-
lems but certain features make it espe-
cially applicable under a wide variety of
conditions. All of us recognize that be-
cause of the relatively large land area re-
quired, the greatest application will no
doubt be small communities, where land is
readily available but where the per capita
costs for conventional treatment plants are
high and the revenues correspondingly low.
Without question this practical minimum
cost method of sewage treatment has made
it possible for many communities to afford
a community water-carried sewerage sys-
tem with its related conveniences andbene-
fits that would otherwise have been impos-
sible.
However, the facility is not limited in its
application to small communities alone. It
has been demonstrated to have a very real
place in meeting the needs of our ex-
panding metropolitan areas. The problems
associated with the sanitary aspects of
suburban housing are known to all of us.
We all realize the limitation of individual
waste disposal systems and the desirabil-
ity of community systems for metropolitan
69
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areas. In the initial developments stages,
however, the high capital investment and
the initial limited tax base often make it
impossible to construct both the necessary
system of sewers and conventional treat-
ment works. This frequently results in the
construction of individual disposal systems
in areas not suitable for their use which at
the best may prove to be only a costly
stop-gap solution to the problem. These
difficulties can be materially reduced if
sewage treatment processes with low first
cost, minimum operating costs, and ca-
pacity for easy expansion, can be provided.
In many instances, such treatment devices
may be needed only as an interim facility
until the time that several developments
can merge into a combined collection and
treatment works. In such cases, salvage
value of the initial sewage treatment in-
stallation is also important.
It is in this field that the stabilization
pond has found real application. The rea-
sons are quite apparent. First, in the ini-
tial stages of the development a greater or
lesser amount of land is available and part
of this can often be set aside for a stabili-
zation pond including a buffer strip sur-
rounding it. Secondly, the system of ponds
necessary to serve the ultimate develop-
ment can often be built in stages as the
population load builds up. Thirdly, the
pond area can be very economically re-
claimed for future housing developments if
and •when subdivision can join a combined
sewer district, thereby realizing an al-
most 100 percent salvage value. In fact,
the reclaimed area may have a consider-
ably greater value than the raw land did
when the development was started. A
fourth and very important advantage is that
the cost of sewer construction is much less
on raw land than when the development is
complete and individual treatment plants
have to be replaced by a community sys-
tem. Many areas have used the stabiliza-
tion ponds most effectively for this use,
the most extensive of which has been right
here in the Kansas City area.
Other areas that have taken advantage of
this method are the Metropolitan Sanitary
District of Greater Chicago, Pittsburgh,
Denver, Seattle, and several areas in Mis-
sissippi. There may be others. The Chi-
cago situation offers what appears to be an
ideal situation. Within the past few years
the Sanitary District has taken in a consid-
erable area north and west of the old Dis-
trict boundaries for which it is responsible
for collecting and treating the waste. It
will take considerable time to provide inter-
cepting sewers to serve all this area and
the District has effectively utilized stabil-
ization ponds to serve these communities
and newly developed housing areas until
such a time as the sewer collection system
is extended.
Other areas in which stabilization ponds
have been effectively used include national
parks, Indian reservations, tourist courts,
boarding schools, and isolated military in-
stallations. Many of our national parks
operate on a seasonal basis and have an
extremely fluctuating load. Stabilization
ponds have many advantages for such con-
ditions. First, the period of operation dur-
ing the summer season is that period when
the maximum biological activity exists and
when the maximum loading can be applied.
Secondly, the stabilization pond requires
no extensive breakin period such as an ac-
tivated sludge plant or trickling filter.
Stabilization ponds have no discharge until
they have filled to an operating level at
which time the processes of purification
are fully established. Thirdly, the sim-
plicity of operation has many advantages
where technical supervision is usually lim-
ited.
The Bureau of Indian Affairs has used
this method of treatment quite extensively
on many reservations and boarding
schools. Here again the simplicity of op-
eration and maintenance are of particular
importance. Probably one of the most in-
teresting applications of this method of
treatment exists in Alaska where a stabili-
zation pond was constructed to serve a
school at Fort Yukon some eight miles
north of the Arctic Circle. This is in the
permafrost area where any conventional
type of water-carried sewerage presents
many costly and difficult operation and
maintenance problems. In an effort to de-
velop improved methods of sanitary sew-
age disposal the Arctic Health Research
Center of the Public Health Service, at An-
chorage, working with the Bureau of Indian
Affairs and the Alaskan Health Department
developed a design for a stabilization pond
to serve the public school at Fort Yukon.
This facility has operated satisfactorily
through two winters and is providing a
simple and economical method of waste
70
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treatment and disposal for this area. This
likewise is a seasonal operation but in this
case the off season is summer. Anderegg
and his associates have reported on this
and other installations in Alaska. (1)
As the use of stabilization ponds has ex-
panded in the municipal field many indus-
tries have likewise shown an interest in
the application of this type of treatment for
various types of industrial wastes. The use
of ponds or lagoons as an adjunct to indus-
trial waste treatment and disposal is not
new. In fact, such use can be traced back
for several decades and it is likely that
they existed prior to the time that their use
was recorded in the literature. Usually,
however, stabilization of the waste was not
the primary objective. They were usually
used as seepage pits, settling basins, or
for holding industrial wastes until greater
dilution was available in the receiving
streams.
The lagooning of vegetable canning
wastes has been practiced for many years
but the organic loadings were invariably of
such magnitude that anaerobic decomposi-
tion always resulted, often accompanied by
offensive odors requiring the application of
sodium nitrate for odor control. More re-
cently, however, several industries are
installing stabilization ponds as a complete
treatment unit. A preliminary review of
this application summarized some 40 or 50
installations serving at least 10 different
types of industry. (2) These installations
varied widely in loadings and types of
waste being created, as well as in design
features such as depth, size of installation,
and methods of operation. As would be ex-
pected organic wastes that have been suc-
cessfully treated by conventional biological
processes have also been amenable to
treatment in stabilization ponds. Similarily,
those wastes that require addition of cer-
tain nutrients to support biological life in
conventional treatment may also require
the addition of nutrients to provide effec-
tive pond treatment.
In general, it may be stated that there is
less uniformity in the design criteria being
applied to the design of industrial waste in-
stallations just as there is less uniformity
in the character of the wastes.
The many applications of this treatment
have not been limited to the United States.
Concurrent with the publication of re-
search results and reports on the success-
ful use of the aerobic type of stabilization
process in this country, many inquiries
were received by the Public Health Service
from numerous foreign countries. A large
number of foreign visitors pass through the
Sanitary Engineering Center annually.
Probably no other subject is of more uni-
versal interest to these people, and
ponds have been constructed in many
foreign countries following the general
design criteria developed in this coun-
try. Through an exchange of correspond-
ence and reports concerning operating
data, experiences, and problems, there
has been much mutual benefit. The Public
Health Service is deeply indebted for this
continued interest and assistance.
OBSERVATIONS ON DESIGN
AND OPERATION
Probably one of the most common ques-
tions in the minds of many of our visitors
is how do design criteria which may be
suitable for cold climates apply to their
country. If there has been any one thing
that may have contributed to the lack of un-
derstanding and confusion concerning de-
sign criteria, it has been this failure to
recognize two extremes in climatic condi-
tions that may require entirely different
approaches in design, i.e. , ice cover vs.
open water. Naturally, in those climatic
regions where long periods of ice cover
prevail it is impossible to maintain aerobic
conditions even with the lowest possible
loading. Consequently, factors governing
the maintenance of an aerobic environment
under open water conditions no longer ap-
ply. During such periods anaerobiasis is a
certainty and the pond temperatures are
only slightly above freezing. This results
in a very much slowed up biological activ-
ity with the resultant accumulation of
sludge deposits which are not dispersed
because of almost complete quiescence.
These solids remain in a refrigerated
condition until spring when increased tem-
peratures speed up biological action, and
the winter's accumulation of fresh sludge
begins to digest anaerobically at such a
rate that so-called "acid digestion" pre-
vails, with a lowering of pH and the poten-
tial production of hydrogen sulfide gases.
Many of us who have lived in these colder
climates remember similar periods of
spring time complaints with Imhoff tanks.
71
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It is fully recognized that during the
summer months loadings considerably
higher than those commonly advocatedhere
in the Plains States can easily be handled.
However, unless there is adequate isola-
tion to minimize the effect of odors that
may prevail during the spring break-up
period it has been the policy to reduce
loadings so that the time required for tran-
sition from anaerobic to aerobic conditions
will be minimized. In those climates where
ice coverage does not prevail, it has been
demonstrated that much higher loadings
than those common in our northern States
are practical. This has been borne out by
actual experience both in this country and
abroad. The Public Health Service experi-
mental ponds at both Fayette, Missouri
and Lebanon, Ohio, have operated with a
minimum of odor at loadings approaching
100 Ibs. of 5-day BOD per acre per day,
even though there have been moderate pe-
riods of ice cover and resulting anaerobi-
asis.
Personal communications from two for-
eign sources may also be of interest. Mr.
H. D. Hodgson, Government Health In-
spector in South Rhodesia, South Africa,
reports that loadings of slightly over 800
population per acre per day had been han-
dled satisfactorily. Mr. Harold A. Taylor,
Chief Health Inspector, Ministry of Local
Government Health Housing, Nairobi, in
commenting upon the operation of pilot
sewage lagoons in Kenya Colony, East
Africa, states that aerobic conditions were
maintained with loadings in slightly-excess
of 200 Ibs. of 5-day BOD per acre per day.
However, when this load increased to ap-
proximately 300 Ibs. per acre per day, the
pond lost its green color and anaerobic
conditions accompanied with typical septic
odors developed. In these warmer climates
it would also seem reasonable to expect
that anaerobic action would be less likely
to produce objectionable odors. Under such
conditions once alkaline digestion is estab-
lished the resulting gases of decomposition
should be essentially the same as those
from normal functioning, unheated, sludge
digester and should be no more objection-
able. Therefore, in such areas, it may not
be necessary to design to satisfy the accu-
mulative effects resulting from a sludge
build-up under long periods of ice cover-
age.
While the studies in this country have
been primarily related to the phenomena
taking place in aerobic environments the
above discussion logically leads to the
question of what would happen should we
utilize anaerobic lagoons. All of us have
read with much interest the pioneering
work that has been done in this field by
Mr. Parker and his associates in Mel-
bourne, Australia and we are indeed fortu-
nate in having him present here at this
conference. He should know, however,
that the results of his work have preceded
him to this country and we already have in
operation at least two ponds employing the
anaerobic-aerobic principle following his
general design criteria.
These two installations are located at
Long Beach and Redmond, Washington.
The first installation was studied by the
Public Health Service and was reported on
at the most recent Industrial Wastes Con-
ference at Purdue in May of this year. (3)
This resort community on the Pacific
Ocean near the mouth of the Columbia
River has high summer and low winter
populations resulting in extreme variations
in loading. The observed loadings ranged
from 185-450 Ibs. of 5-day BOD per acre
per day on the primary ponds, with reduc-
tion ranging from 40-70 percent, the ma-
jority approximating 60 percent. The
aerobic pond loadings varied from 13-40
Ibs. of 5-day BOD per acre per day re-
sulting in reductions varying from 50-85
percent. The over-all BOD removal at this
installation ranges from 74-96 percent. It
may be of interest to report that during the
study period algal growths were frequently
evident at the surface of the anaerobic
ponds while anaerobic digestion of sewage
solids was taking place at the bottom. In
general, the operation of this facility has
been extremely satisfactory. Some septic
sewage odors were noticed during the
summer months in the late evening hours
but the operator reports that these were
quite effectively controlled by recirculat-
ing from the aerobic pond to the anaerobic
ponds for a period of approximately two
hours during the afternoons when the dis-
solved oxygen content in the former ponds
was at a maximum.
The other installation at Redmond,
Washington serves a residential develop-
72
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merit adjacent to Seattle. The Washington
State Health Department and the State Wa-
ter Pollution Control Commission approved
this as an experimental treatment plant to
be abandoned when interceptor sewers
were provided by the municipality of Met-
ropolitan Seattle. A study of this installa-
tion was conducted during the period
October 1958 to September 1959 by Mr.
Walter L. Berschauer a graduate student
at the University of Washington, now with
the Washington Health Department. The
authors are deeply indebted to Mr. Ber-
schauer for a copy of his thesis "Research
and Investigation on a Multiple Cell Sewage
Stabilization Pond" and his permission to
use some of the data.
A series of analyses extending from
March 19 to June 25, 1959 gave the follow-
ing results:
The anaerobic pond was loaded at a rate
of 463 Ibs. of 5-day BOD per acre per day
while the entire aerobic section was loaded
at a 20-lb. rate. However, since the aero-
bic section consisted of three ponds in se-
ries the load on the first pond was approx-
imately 75 Ibs. per acre per day. The two
remaining ponds resulted in relatively
little additional BOD removal but did serve
to reduce the number of algae in the final
effluent. The removals average 61 percent
for the anaerobic pond with an over-all re-
duction of 91 percent. Berschauer reports
that during winter operation little or no
odors were detected in the anaerobic sec-
tion. Odors were noticeable in the early
spring from this section, at which time
rapid gas production was apparent and this
carried solids to the surface. Such odors
as appeared on the aerobic ponds were of
a fishy nature and were attributed prima-
rily to algae.
As a result of his studies Berschauer
concluded that BOD loadings as high as 78
Ibs. per acre per day could be applied on
the aerobic ponds and loadings in excess of
555 Ibs. per acre per day could be applied
to the anaerobic ponds without difficulty.
CONCLUSIONS
In concluding this rather rambling dis-
cussion of where we started, where we
are, and where are we going, I think we
can point out some well substantiated ac-
complishments.
1. Research and field studies carried
out in this country during the past
ten or so years have definitely
proved the efficacy of raw sewage
stabilization ponds as a practical
minimum-cost method of sewage
treatment having wide application
throughout the world.
2. Properly designed and operated sta-
bilization ponds may be expected to
provide a degree of purification
comparable to that obtained by con-
ventional complete treatment proc-
esses and the effluent may be
discharged in a similar manner.
Like any other sewage treatment de-
vice stabilization ponds have both
advantages and disadvantages. They
should not be looked upon as a pana-
cea for all sewage treatment needs
but may be considered in the eco-
nomic and engineering evaluation of
waste treatment methods.
3. Although stabilization ponds appear
to be simple in their design and op-
eration, it is essential that they be
designed by people having a thorough
knowledge of the factors contributing
to their success and/or failure. The
design criteria may vary radically
between different climatic and geo-
graphic areas and for these reasons
the designing engineer should not
attempt to blindly apply such cri-
teria without considering the local
factors involved.
4. On the basis of operating experience
in this country and abroad, organic
loadings of at least 100 Ibs. of 5-day
BOD per acre per day are no doubt
feasible for ice-free climates or
where potential odors at ice break
up are not a controlling factor.
5. The factors to be considered in loca-
tion and site selection for these fa-
cilities are essentially the same as
for other more conventional types of
sewage treatment plants.
6. While there is no epidemiological
evidence indicating that stabilization
ponds constitute a serious public
health hazard, the potential for the
propagation of insects and other pos-
sible disease vectors is no doubt
73
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greater in ponds than at conventional
treatment works and requires con-
sideration by the designer.
Although our knowledge of this method of
waste treatment has increased greatly dur-
ing the last 10 or 15 years this has also
made us cognizant of the need for even
more knowledge on the subject. The fol-
lowing comments point out several areas
in which our knowledge is lacking.
1. Naturally, we need much more funda-
mental information on the whys and
wherefores of algal-bacterial rela-
tionships and the factors affecting
them. One prominent researcher in
the field recently told me that he felt
much more confident of his under-
standing of the basic factors after
one or two years of working with the
problem than he does now after sev-
eral years of effort. Without doubt,
much, much more basic research is
needed together with the related field
studies and observations necessary
to fully evaluate the applicability of
these scientific findings. On the other
hand, I seriously question that we
will ever be able to develop design
formula that will adequately consider
the variability of all factors affecting
the functioning of the processes. At
least we cannot wait for that time to
experiment with new ideas and apply
the available knowledge toward pro-
viding better and lower cost sewage
treatment.
2. The viability of pathogens and virus
and possible bactericidal action of
algae require additional study.
3. More knowledge concerning effective
insect control measures is highly de-
sirable. Although we have experienced
very little difficulty from this prob-
lem in this country, we have re-
ceived reports where it has become
a serious problem elsewhere. Also,
if these facilities are going to have
world wide application we need to
give consideration to possible con-
trol methods for other types of dis-
ease vectors. One of these that
comes readily to mind is the possible
significance of stabilization ponds as
a link in the chain of transmission of
schistosomiasis where that disease
is prevalent.
4. Greater effort should be devoted to
the evaluation of this method of waste
treatment for wider application in the
industrial field.
5. The application of anaerobic-aerobic
processes deserves consideration.
This would appear to have application
in warmer climates where cyclic
sludge problems are less likely.
6. Consideration should be given to in-
corporating various adjuncts or ad-
ditional types of equipment in the
design of these facilities in order to
improve their efficiency. For in-
stance, the reported beneficial
effects of recirculation during lim-
ited critical periods warrants further
evaluation. We should not lose sight
of the fact, however, that the addi-
tion of mechanical equipment with its
attendant demands for maintenance
tends to nullify one of the principal
advantages of this method of treat-
ment, namely, simplicity. On the
other hand, the area requirements
and short-time critical seasonal
problems may well warrant the in-
clusion of mechanical devices purely
from an economical standpoint.
These are just a few of the areas in
which I believe we need to direct our future
efforts. I am sure that before this sympo-
sium is finished, many other areas of in-
vestigation will become apparent.
In closing I would like to say that I think
that it is very appropriate that this sympo-
sium is taking place here in the general
area where raw sewage stabilization ponds
got their start and I wish to commend the
Missouri Basin Engineering Health Council
for initiating this meeting.
REFERENCES
1. Anderegg, J. A., Walters, C. F. ,
Milliard, D. , and Meyers, H. F. ,
" 'Eskimo' Algae Make Lagoons Work
at the Arctic Circle. " Wastes Engi-
neering, 31, No. 6, June I960.
2. Towne, W. W., and Pahren, H. R. ,
"Use of Stabilization Ponds in Treat-
ing Sewage and Industrial Wastes. "
Proc. 8th Southern Municipal and In-
dustrial Wastes Conference, Chapel
Hill, North Carolina, April 1959.
3. Wilson, J. N. , McDermott, J. H. ,
and Livingston, A. , III. , "Perform-
ance of a Sewage Stabilization Pond
in a Maritime Climate: 1957-1958."
Proc. 15th Purdue Industrial Wastes
Conference, May I960, (in Press)
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WASTE STABILIZATION LAGOONS
DESIGN, CONSTRUCTION, AND OPERATION PRACTICES
AMONG MISSOURI BASIN STATES
Glen J. Hopkins*
Before 1950, use of lagoons as sole and
permanent sewage treatment facilities gen-
erally were discouraged. About 1952, great
upsurge of interest in their use at many
localities throughout the country empha-
sized the desirability of documenting the
design, construction, and operating prac-
tices generally used. At its 1958 meeting
at Deadwood, South Dakota, the Missouri
Basin Engineering Health Council, in rec-
ognition of this need, appointed a Commit-
tee to accomplish this objective. The Com-
mittee report, approved by the Basin Coun-
cil on January 21, I960, serves as the
basis of my presentation today, and copies
of that report are available today, for any-
one interested.
The Committee soon realized that waste
stabilization lagoons have been adapted for
successful use under highly varying con-
ditions. Like other methods of sewage
treatment, they can be designed to provide
intermediate, secondary, or higher levels
of removal. Variations in water quality,
rain fall, evaporation, water use per
capita, soil conditions, nature of receiving
watercourses, dilution water available,
uses of the receiving waters, and similar
factors permit design to vary widely.
The many installations demonstrating
satisfactory performance with highly di-
vergent design criteria, impressed the
Committee that it was not desirable to out-
line firm design criteria. Its members
elected to outline range of design practices
satisfactorily employed in the Basin, leav-
ing each individual State wide latitude as
to specific practices to be recommended
for that State.
The Committee report was based on the
best information now available, heavily in-
fluenced by experience in those States hav-
ing a large number of installations, and
the premise that waste stabilization lagoons
are a proven and demonstrated method of
satisfactory waste disposal to be consid-
ered, along with other methods of treat-
ment, in the engineering and economic
analyses leading to final selection of a
sewage treatment facility.
The terms "recommended" and "should"
are use to denote widely used practices,
and do not imply a mandatory requirement
fbr any specific State or installation.
At its 1956 meeting at Helena, Montana,
the Missouri Basin States adopted the ter-
minology of "waste stabilization lagoons".
Similar action was taken by the Great
Lakes-Upper Mississippi River Board of
State Sanitary Engineers at the March 1959
meeting at Chicago, Illinois. In this dis-
cussion, the terms "waste stabilization la-
goons", "stabilization lagoons" and "la-
goons" are used interchangeably. The term
"ponds" is still used by some of the Basin
States.
PRELIMINARY ENGINEERING REPORT
As for other sewage treatment works, a
preliminary engineering report on the pro-
posed facility should be prepared and sub-
mitted to the appropriate State agency for
review prior to development of final plans
and specifications. This report should indi-
cate the location and topography of the pro-
posed site, volume and characteristics of
sewage flow, industrial wastes, size and
shape of units, surface and subsurface soil
conditions, nature of receiving watercourses,
downstream water uses, dilution water
available, and geographical location with
respect to residences, commercial devel-
opment, water supplies and other topo-
graphic features.
Preliminary reports should be reviewed
and evaluated on an individual basis, with
local conditions receiving appropriate con-
sideration.
*U. S. Public Health Service Region VI, Kansas City, Missouri.
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LOCATION
Stabilization lagoons, like other sewage
treatment facilities, should be located as
far away from existing and future residen-
tial and commercial developments as is
reasonably practicable and economically
feasible. Like other sewage treatment fa-
cilities, location of a waste stabilization
lagoon depends upon many factors and each
installation merits individual considera-
tion. If not unduly influenced by cost, con-
sideration should be given to the probable
course of possible expansion and the direc-
tion of prevailing winds. Other factors per-
mitting, preference should be given sites
that permit unobstructed wind action on
water surface.
Early installations had the benefit of
considerable separation from residences,
and the impression developed that substan-
tially greater remoteness is required for
lagoons than for other sewage treatment
devices. Experience has demonstrated that
lagoons usually can be located as close to
habitation and other developments as can
other sewage treatment processes. Gener-
ally, it is recommended that isolation re-
quirements for lagoons be identical with
and determined by the same factors that
are associated with other sewage treatment
plants. As with other plants, provision for
probable future expansion, including land
availability, may well be considered.
While no evidence of underground pollu-
tion affecting water supplies has been at-
tributed to existing installations, the sig-
nificance of pollution of underground waters
is so great that this aspect of location
merits very serious consideration. Except
for fissured rock or coarse gravel for-
mations, travel of bacteriological pollution
through significant horizontal soil distances
is not considered probable. Chemical pol-
lution, including detergents, may travel
much further than bacteriological pollution
in normal soil formations.
AREA AND LOADING
Early stabilization lagoons in North
Dakota were located in areas of inexpen-
sive, relatively level land, and were bas-
ically designed for one acre of water surface
per 100 population, or population equiva-
lents, of organic wastes expressed in terms
of 5-day 20° C B.O.D. This basis of de-
sign was predominantly one of economics
and experience, since cost was well within
the financial capabilities of North Dakota
communities and the installations per-
formed quite satisfactorily. Later experi-
ence in North Dakota revealed that sub-
stantially heavier loadings, arranged
primarily to insure water level mainte-
nance, did not mitigate against successful
performance. Similar experiences have
been observed in Missouri, Kansas, Ne-
braska and Wyoming.
Five day 20° C B.O.D still is used as
one factor of design in most States of the
Missouri Basin. Total first stage B.O.D.,
has on occasion been used, particularly
where significant industrial wastes are in-
volved.
Loadings, and subsequently the lagoon
area, are influenced by many factors, in-
cluding, but not necessarily limited to:
water use per capita, evaporation, rainfall,
seepage, the degree of treatment desired,
growth prospects, and the basic plan of
operating the facility. Optimum loading and
area should reflect appropriate considera-
tion to all pertinent factors.
In cold climates, where substantial ice
cover may be expected for an extended
period, it may be desirable to operate the
facility to retain all wintertime flows. In
other climates, lagoons may be operated
on a "flow-through" principle, with continu-
ous overflow. In some instances, essen-
tially complete retention may serve as a
basis of design rather than B.O.D. load-
ings.
"Flow-through" lagoons receiving raw
sewage normally employ a minimum of 60
days retention, with 90 to 120 days fre-
quently specified. A high degree of coli-
form removal is assured even with 30 day
retention. Installations receiving partially
treated sewage may provide lesser reten-
tion, usually in relation to the degree of
reduction accomplished by prior treatment.
Lagoon loadings of from 10 to 34 pounds
of 5-day 20° C B.O.D. per acre per day
have demonstrated satisfactory service
throughout wide areas of the Missouri
Basin. The lower range permits longer
retention and greater flexibility for handling
future increases in waste loadings from
population growth or industrial increases.
However, the lower loading generally re-
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suits in a lesser volume of sewage per unit
of area, and enhances the possibility of
operational difficulties brought on by in-
ability to maintain satisfactory liquid depth,
particularly in areas of low per capita water
use, low rainfall, high evaporation, or sig-
nificant seepage. While primary considera-
tion is given to organic loading, in many
instances the area finally decided upon is
based upon both the organic loading and the
hydraulic loading.
Lagoons have clearly demonstrated ability
to handle satisfactorily substantially higher
loading during summer periods, making
them particularly appropriate for resort
areas and similar instances where heavy
summer population is anticipated.
B.O.D. loadings up to 68 pounds of 5-day
B.O.D. per acre have been employed in
Missouri, particularly in sub-divisions
where land costs are high and the lagoon is
planned as an interim installation, to be
replaced in reasonable time by trunk sewers
leading to a more permanent installation.
These higher loadings are permitted only
for installations viewed as "temporary",
and must include provision for dosage of
sodium nitrate as needed.
For lagoon units operated in series,
design should recognize that the entire or-
ganic load will be applied to the primary
unit.
Lagoons should be of such shape that
there are no narrow or elongated portions.
Round, square, or rectangular units with
length not exceeding three times the width,
are considered most desirable. Dikes
should be rounded at corners to minimize
accumulation of floating materials.
MULTIPLE UNIT INSTALLATIONS
Many Missouri Basin installations em-
ploy multiple units, some operating in
parallel, others in series. Series opera-
tion is beneficial where a high level of
B.O.D. or coliform removal is important.
The effluent from secondary units in series
operation has much lower algae concentra-
tions, with resultant decreases in color and
turbidity. However, some multiple unit in-
series operating installations have been
designed to provide virtually complete re-
tention of wastes.
Many installations provide flexibility so
that units may be operated either in series
or in parallel. Except for small installa-
tions, this has considerable advantage.
This may also be important in areas of low
water usage, high evaporation, or consid-
erable seepage. For small installations (6
to 8 acres) a single unit seems conducive
to better circulation, but reasons other
than circulation make two units preferable
even for small installations.
The additional cost of equipping units for
both series and parallel operation is usually
quite nominal. In some instances, actual
savings can be demonstrated because of the
lesser volume of earthworkpossible through
better adaptation of two or more smaller
units to over-all topography. The flexibility
may have substantial advantage, particu-
larly as volume and loading are increased
through population growth or other causes.
Except for small installations (6 to 8 acres
or less) it is recommended that units be
designed to permit both series and parallel
operation as desired.
For larger communities, two or more
units have advantage over a single unit.
Wave action is more intense on larger
bodies of water, and prevailing topography
often permits lesser construction costs
through multiple units. While circulation is
influenced by area, there appears to be
little advantage in this respect to installa-
tions in excess of 40 acres.
SURFACE RUNOFF
Lagoons should not receive significant
amounts of surface runoff. If necessary,
provision should be made for diverting
surface water around the ponds. For new
installations, and for installations where
maintenance of satisfactory water depth
may be a problem, the diversion structure
may permit entrance of the surface water
into the lagoon when desired, yet preclude
it at all other times. Silt that would be car-
ried into the installation by runoff must be
considered.
DIKES
Dikes should be so constructed as to
prevent excessive seepage through the dikes
or between the embankment and the natural
77
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ground. Compaction afforded by the use of
conventional construction equipment is
usually adequate. Prior to starting the em-
bankment, vegetation should be removed,
and the area upon which the embankment
is to be placed should be scarified. While
experience demonstrates that it is generally
unnecessary to key the dikes into impervi-
ous subsoil, this precaution may be advis-
able for sandy top soils or for dikes repos-
ing on shale or similar formations.
The dikes should be of sufficient width to
accommodate mowing machines and other
maintenance equipment. A width of 8 feet
is generally considered adequate, and lesser
width may be approved for small installa-
tions.
Dike slopes may be influenced by the
nature of the soil and the size of the instal-
lation. For outer slopes, 3 horizontal and
1 vertical is conducive to satisfactory
maintenance, although economical use of
excavation material may warrant flatter
slopes. Inner slopes are generally designed
from 3 or 4 horizontal to 1 vertical, although
slopes exceeding 5 to 1 are sometimes
specified for larger installations, and
slopes steeper than 3 to 1 may be warranted
for small installations. Flat inner slopes
have the distinct disadvantage of added
shallow areas conducive to emergent vege-
tation. Wave action is more severe for
larger installations, warranting considera-
tion of flatter inner slopes. However, ob-
servation reveals that a given installation
will develop a particular slope at the water
line rather independent of the slope origi-
nally provided, the constructed slope being
adjusted by wave action to give a "dished"
effect near the water line.
The freeboard to be specified is to some
extent influenced by the size and shape of
the installation, as wave action is more
pronounced on larger bodies of water.
Freeboard should be sufficient to facilitate
necessary maintenance operations without
accident hazard Three feet above maxi-
mum liquid level is usually specified as
minimum freeboard. However, 2 feet is
considered adequate by some States, par-
ticularly for installations of 6 acres or
less not exposed to severe winds.
LIQUID DEPTH
Optimum liquid depth is influenced to
some extent by lagoon area. Relation of
depth to size should be such as to facilitate
circulation within the body of water, and
larger installations may allow greater
liquid depth than would be considered for a
smaller facility. The basic plan of opera-
tion may also influence depth. Lesser
depths are conducive to emergent vegeta-
tion and enhanced mosquito breeding. Ex-
perience in the Kansas City area has
demonstrated 2 to 3 feet as the most de-
sirable operating depth during the pro-
longed periods of cool, cloudy weather,
occasionally encountered in early spring
or late fall. These installations serve sub-
divisions, are heavily loaded, and are less
than 10 acres in area. Experience has
demonstrated however, that greater depths
are desirable during the summer to dis-
courage emergent vegetation.
Experience has conclusively demonstrated
the advantage of facilities which permit
operation at selected depths up to 5 feet,
and provision for additional depth may be
desirable for large installations. Facilities
for adjusting water levels can be provided
at little increase in cost, and permit opera-
tional flexibility of considerable advantage.
For example, where winter retention is
visualized, the operating level can be
lowered as desired before ice formation
and gradually increased by the retention of
winter sewage flow. In the spring, the level
can then be lowered to any desired depth at
the time surface runoff and dilution water
are generally at a maximum. Shallow opera-
tion can be maintained during the spring,
increasing the depth as necessary to dis-
courage emergent vegetation. In early fall,
the levels can be lowered before cloudy
periods are encountered and again be ready
for retention of winter sewage. In areas of
high evaporation, as Western Kansas, a
full lagoon in late spring may well be an
operating objective.
Facilities to permit operation at selected
depths are desirable for any installation,
and can be provided at very little increase
in cost. For lagoons of considerable size,
provision for periodic operation at depth
greater than 5 feet may be advantageous.
LAGOON BOTTOM
The lagoon bottom should be made as
level as possible with conventional dirt
moving equipment and operations, and the
finished elevation should not vary more than
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plus or minus 6 inches from the average
elevation of the bottom.
The lagoon area should be cleared of
excessive vegetation and debris. This
material should not be included in the
waterside two-thirds of the embankment,
but may be used if judiciously placed in the
outer third of the embankment. Rock or
other porous material may also be placed
in the outer one-third of the embankment,
but should be covered with earth to facili-
tate maintenance.
The bottom should be well compacted and
relatively tight to avoid excessive seepage.
Removal of porous top soil and compaction
of subsoil improve the water holding char-
acteristics of the bottom, and adequate
compaction may be as important in this
regard as soil characteristics. Proper
compaction can usually be accomplished
through judicious use of conventional earth
moving equipment, although additional
treatment, as sheep-foot rolling, may be
justified.
The ability to maintain a satisfactory
water level in the lagoon is one of the most
important aspect of design; one for which
the consulting engineer must assume re-
sponsibility. Where excessive percolation
is a problem, increased hydraulic loading
or partial sealing may merit consideration.
Porous areas, as gravel pockets, should
receive particular attention. Removal of
gravel or sandy pockets and replacement
with well compacted clay or other suitable
material may be indicated. Limiting values
of acceptable percolation may be merited
in some areas, as a measure againstwhich
sealing of porous bottoms will be required.
Influent pipes discharging vertically up-
ward have been successfully used, but ap-
pear to demonstrate no advantage. Some
States discourage a vertical discharge be-
cause of possible accumulation of grit in the
lime. For horizontal discharge, a suitable
concrete splash plate should be constructed
around the point of discharge to minimize
erosion in the vicinity of the terminal
structure.
OVERFLOW STRUCTURES
Overflow structures should be designed
to permit operation of the lagoon at selected
water depths. The outlet structure should
permit lowering the water level at a rate of
at least 1 foot per week while the facility
receiving its normal load. It should be of
adequate size and suitable construction to
permit easy access and normal mainte-
nance operation. It is desirable that pro-
vision be made for complete draining of the
lagoon.
During ice-free periods, discharge should
be taken near, but below, the water surface.
This releases effluent of the highest quality,
and insures retention of floating solids. For
operation during periods of ice cover and
ice formation, the discharge is usually
from a point substantially farther below
the surface. However, some States have
successfully used surface overflow pipes
during prolonged freezing. Overflow struc-
tures generally comparable to a sewer
manhole are most frequently employed,
with selective level discharge facilitated
through valved piping or other adjustable
overflow devices. Stop planks of creosoted
lumber have been successfully used in some
cases.
Overflow lines should be vented if the
design would otherwise permit siphoning.
The overflow and outlet structure should be
designed to meet the needs of the individual
installation, with due consideration to the
plan of operation. For "flow-through" la-
goons the maximum rate of effluent dis-
charge is considerably less than the rate of
peak sewage flow, because of lagoon losses
and the leveling out of peak flows.
INTERCONNECTING PIPING
Interconnecting piping for multiple unit
installations should be of suitable materials
and properly located so as to facilitate
maximum retention in the facility. In some
States, cast iron is specified for intercon-
necting piping. Valving or other arrange-
ment to regulate flow between structures
is recommended. It is desirable that each
unit of a multiple unit installation be
equipped for flexible depth control. The
influent pipe to the secondary unit should
discharge horizontally at or near the la-
goon bottom so as to minimize need for
erosion control measures. The inlet to
secondary units can be located as near the
dike as construction permits. If operation
in parallel is to be considered, inlets
should be designed as though each unit
were to be operated as a primary unit.
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INDUSTRIAL WASTE
Lagoons may be used for treating indus-
trial wastes that are amenable to biological
treatment, or a mixture of organic indus-
trial wastes and domestic sewage. Instal-
lations are now successfully serving oil
refineries, slaughter houses, dairy and
creamery establishments, poultry proces-
sing plants, and rendering plants. Special
study should be given the industrial wastes
whenever they constitute a significant por-
tion of the total load. Recommendations
for loading and area, included in the pre-
ceding paragraphs, may be used to guide
loading and area of facilities receiving
industrial wastes. Possible toxic effects
of industrial wastes should not be over-
looked Toxic materials in concentration
that would interfere with other biological
sewage treatment processes should be han-
dled in lagoons only after thorough study
and evaluation.
Relatively little experience is available
in the sealing of lagoons where high seep-
age rates are expected. Some clogging of
permeable soil results from sewage solids,
even though the sludge layer is extremely
thin. Some lagoons have been built with
multiple units to facilitate heavy original
loadings. The entire sewage load is dis-
charged to the smaller area, and when
water holding capabilities are obtained, the
flow is diverted to another unit.
Some use has been made of bentonite,
asphaltic coating, clay blanket, and other
sealing materials. Sealing by these methods
can best be considered as a special prob-
lem for individual installations, with the
consulting engineer basically responsible
for adequate sealing to permit maintenance
of satisfactory water levels.
INFLUENT LINES
The influent line to primary units should
discharge far enough from any bank to in-
sure minimum interference with normal
circulation. For small installations, the
discharge should be at the approximate
center of the lagoon. For medium sized
installations, there appears to be little
advantage in locating the inlet more than
200 feet from the nearest bank, with 400
feet desirable for lagoons of 40 acres or
more in area. Multiple inlets appear to
have some advantage in dispersing solids
uniformly throughout the lagoon, particu-
larly in large installations.
Gravity inlets to primary units should
slope on a uniform grade from the manhole
at the terminus of the outfall sewer to a
point approximately one pipe diameter
below the toe of the inner or waterside
slope of the dike. From this point the pipe
is usually laid on a zero grade to the point
of discharge, with the top of the pipe being
slightly below the average elevation of the
lagoon floor. Placing the bottom of the pipe
on the lagoon floor, the use of earthen
dikes, piling or other pipe supports, or the
use of shallow dike formed areas around
the inlet are not recommended, as there
is some evidence that this may interfere
with normal circulation.
Gravity lines and inverted syphons have
been successfully used in many installations
to discharge untreated sewage to primary
units. Submerged portions of the influent
line should be considered as under slight
pressure, with appropriate materials and
methods of construction. The size of the
line should not be reduced along the sub-
merged portion. Materials generally ac-
cepted for underground use may warrant
consideration for use as gravity influent
lines. Consideration should be given to the
possibility of septicity, soft foundations,
ice cover, and other loading problems.
The influent line may advantageously
discharge horizontally, into a shallow,
saucer shaped depression. This depres-
sion should have a minimum depth equiva-
lent to the outer diameter of the pipe and a
maximum depth of the pipe diameter plus
one foot, with'a radius varying from 25-100
feet depending on the size of the unit. The
depression, intended only to facilitate sub-
mergence of sewage solids while the lagoon
area is becoming saturated and covered
with liquid, is particularly important for
installations serving new sewer systems.
MISCELLANEOUS
Embankments should be seeded along the
outer slope, the top, and along the inner
slope to the normal water line. This mini-
mizes erosion, facilitates weed control,
and permits the maintenance necessary for
good appearance. Alfalfa and similar long
rooted crops should not be used. The County
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Agricultural Extension Agent can usually
advise of a hardy, locally suited permanent
grass which will not interfere with the
water holding capacity of the dike.
Riprap or other protection is warranted
only under unusual conditions, such as pro-
tection of dikes from erosion due to severe
flooding of the adjacent watercourse, or
extremely severe wave action. Possibility
of floods should be considered as lagoon
dikes, like other earthen embankments,
would be subject to flood damage.
The lagoon area should be enclosed with
a suitable fence to preclude entrance of
livestock and to discourage trespassing.
Fences consisting of 3 or 4 strands of tightly
stretched barbed wire have been found to
facilitate mowing and other maintenance
operations, and otherwise to be completely
satisfactory unless swine or poultry have
access to the area. For lagoons serving
schools, resorts, or similar facilities,
chain link or other special fencing may
merit consideration.
At least one vehicle access gate should
be provided.
The nature of the facility should be
clearly designated through appropriate
signs properly located at suitable intervals
along the fence. The signs need only desig-
nate that the facility is a sewage treatment
device and advise against trespassing.
For lagoons serving combined sewer
systems, suitable grit removal facilities
may be appropriate. Excessive grit may
result in interference with circulation or
discharge, through excessive accumulation
of heavy material at the point of inlet dis-
charge.
Study and evaluation of lagoons may be
greatly expedited by providing a flow
measuring device for influent and effluent.
These devices need not provide continuous
measurement, and may be quite inexpen-
sive. For example, a manhole on the in-
conning sewer and one in the lagoon over-
flow line may be equipped so that a weir
plate can be easily slipped into place dur-
ing periods of flow measurement. A uni-
form receptacle for the weir plate will
permit the State Agency to provide standard
weir plates to expedite special studies.
Flow measuring units should be located as
close to the lagoon facility as feasible and
practicable, but should not be located in
submerged portions of a sewer.
Soil sterilization along the shallow water
portion of the dikes has been found to be
effective in controlling weeds in Kansas.
The sterilizer, to be effective, should be
resistant to leaching and toxic to weeds
but not to algae. Application is made by
power spray prior to filling of the lagoon.
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POND TREATMENT OF
MEAT PACKING PLANT WASTES
F. W. Sollo*
Oxidation ponds have become a very
common method of sewage treatment for
small communities. Little has been re-
ported, however, on the use of these de-
vices for the somewhat stronger wastes of
the meat packing industry. Over a period
of ten years, we have gained some experi-
ence with the use of ponds for this applica-
tion, and feel that they have certain advan-
tages where sufficient space is available
and where the climate is suitable.
In 1951, a problem confronted Swift &
Company at its plant near Moultrie, Geor-
gia. The waste from this plant was dis-
charged to a small stream which was es-
sentially dry for several months of each
year. A chemical treatment plant had been
provided but did not produce the required
degree of treatment. Unsatisfactory con-
ditions prevailed throughout the dry sum-
mer months.
At that time, the use of oxidation ponds
had been reported for a number of munici-
palities and army installations (1,2, 3). It
appeared that this method of treatment of-
fered the advantages of a low investment or
construction cost, simplicity of operation,
and production of an effluent which was
stable even with no dilution. On the other
hand, the reported loadings, in the range
of 50 Ibs. of BOD per acre per day, indi-
cated that large areas of level land would
be required. In addition, there was no re-
ported experience with this method for
meat packing wastes. To evaluate the
method, it was decided to construct a pilot
scale pond in connection with our plant at
Moultrie.
In the course of preliminary laboratory
tests, it was found that ponds could be op-
erated anaerobically without producing ob-
jectionable odors. The potential loading and
BOD reduction per unit area in anaerobic
ponds appeared to be considerably higher
than that possible for oxidation ponds. This
greater efficiency was expected, and a sim-
ilar finding had been reported in the lit-
erature. (3) The absence of odor, at least
of an offensive character, had not been an-
ticipated. In view of the favorable labora-
tory experience, an anaerobic pond was
also constructed for test purposes at
Moultrie.
PILOT SCALE TEST
The first anaerobic pond had a capacity
of 8,000 gallons and was approximately 5ft.
deep. The waste was added near the bottom
at one end of the pond, and the effluent was
taken off about a foot below the surface,
near the opposite end. Digested sludge
from a municipal treatment plant was added
initially to obtain the desired fermentation.
A number of operating difficulties were
encountered, due to the small size of the
pond and the small waste flow required.
Sedimentation with a very short detention
period, and grease removal, were applied
to the influent, but occasionally solids of
sufficient size to interfere with the pumps
or measuring devices would pass the pre-
treatment facilities. These were the only
problems which arose, and there appeared
to be no objectionable odor.
Over a period of three months, this pond
produced an average BOD reduction of
78.6%, with an influent BOD of 1680 mg.
per liter, pond temperature of 72° F. , and
a detention period of 4.4 days.
The oxidation pond had an area of 0. 53
acres and was approximately 3 feet deep.
A recirculation system was provided which
sprayed a mixture of the raw waste and the
pond contents through a number of nozzles.
Recirculation was maintained at 100 gallons
per minute continuously. This served to
distribute the load over the pond surface
and provided some degree of aeration. A
•Sanitary Engineer, Swift & Co., Chicago, Illinois. Also presented at the 15th Annual Purdue Industrial Waste Conference,
May 3. 4, and 5, 1960.
82
-------
heavy BOD load was maintained with the
object of determining the maximum possi-
ble loading.
Over a three month period this pond pro-
duced a 90% BOD reduction with an influent
BOD of 1450 mg. per liter, detention pe-
riod of 50 days, and a BOD loading of 243
Ibs. per acre per day. The effluent was
green and rather turbid, due to the unicell-
ular algae produced. Oxygen concentrations
far above saturation were observed near
the pond surface during daylight hours,
although none was found below a depth of
18 to 24 inches even in daylight, and that
in the surface layer was dissipated rapidly
as light intensity decreased.
From these tests it appeared that the ox-
idation pond could handle loadings some-
what higher than were generally being used,
and would produce a stable effluent. On the
other hand, the anaerobic pond did not pro-
duce a stable effluent but was far more ef-
ficient in BOD reduction per unit area.
Thus a combination of these ponds, operat-
ing in series, was an obvious choice. To be
certain that the effluent from an anaerobic
pond could be handled with no special prob-
lems in the oxidation pond, our facilities
were modified to permit a test with series
operation.
A portion of the previous oxidation pond
was dammed off for use as an anaerobic
pond. (Fig 8) This section was approxi-
mately 50 feet square and had a capacity
of 100,000 gallons. The oxidation pond was
reduced to 0.40 acres by this change. Re-
circulation was continued and in the oxida-
tion pond but the spray nozzles were elim-
inated. Thus distribution of the load was
maintained, but the aeration formerly pro-
vided was eliminated. An appreciable
power saving appeared possible by this
change.
The ponds were operated in this manner
for a period of 11 months. Typical operat-
ing data are given in Table 28.
The BOD of the final effluent in these
tests varied from 35 to 270 mg. per liter.
With other methods of treatment this efflu-
ent would be considered unsatisfactory for
discharge to a dry stream bed. It appeared
unlikely, however, that any nuisance would
be caused in a stream by this effluent as
long as the pond itself remained stable.
Dilution in the stream, if any were avail-
able, and reaeration, should improve con-
ditions over those prevailing in the pond.
For these reasons, it was thought that this
effluent should be satisfactory.
BOD data may be misleading on such an
effluent, since the algae will consume oxy-
gen in darkness as in the normal BOD test,
but will produce oxygen with sufficient
light. Our data were also affected by the
TABLE 28
PONDS IN SERIES
Average Data, 6/1/62 to 3/28/53
Anaerobic Pond
Detention
BOD Loading
Influent BOD—
Effluent BOD
BOD reduction 65.4$
4.6 days
11.2 Ibs. per 1000 cu.ft. per day
820 mg. per liter
mg. per liter
Oxidation Pond
Detention 18.4 days
BOD Loading 130 Ibs. per acre per day
Influent BOD 284 mg. per liter
Effluent BOD 116 mg. per liter
BOD reduction 59.2*
83
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fact that the samples were frozen for pres-
ervation, killing most of the algae. Unfro-
zen samples, diluted as in the BOD test,
but incubated in daylight, produced oxygen
rather than exerting a demand. The same
samples, with normal incubation, exerted
a normal oxygen demand.
FULL SCALE INSTALLATION
With the data obtained in these tests, it
was decided to proceed with installation of
a pond system of treatment for our Moul-
trie plant. This was completed in 1955,
operation starting in November.
The existing chemical treatment plant
was left intact, but chemical addition was
stopped. Thus these facilities served for
primary sedimentation and grease recov-
ery.
The anaerobic pond, shown in Figure 9,
is 192 ft. x 320 ft. at the surface, and has
a 14 ft. water depth. The banks are of
earth construction and have a slope of 1 to
3. The approximate volume of this pond is
4. 2 million gallons. A concrete pad was
provided at the water line to prevent ero-
sion and weed growth.
As in the pilot scale ponds, the waste is
introduced near the bottom at one end and
the effluent removed at the other end. Un-
derflow baffles were profided at the efflu-
ent weirs to prevent loss of floating solids.
Sludge is recirculated from the pond bot-
tom and mixed with the influent waste to
obtain maximum possible contact.
No heating facilities were provided due
to the mild climate, and four years of suc-
cessful operation indicates that heat is not
required. However, occasional extended
cold weather has resulted in somewhat re-
duced efficiency. The effect on efficiency
is noted when the pond temperature re-
mains below 75 F. for a prolonged period.
The oxidation pond, shown in Figure 10,
is irregularly shaped and has a total sur-
face area of 19.2 acres and a depth of 3
feet. Here again, the banks are protected
at the water level with a concrete pad. The
waste entering this pond consists of the ef-
fluent from the anaerobic pond, condenser
water, and storm water.
The waste is mixed with the recirculated
flow of pond contents and distributed along
the west bank by a flume and series of
twelve weirs. Effluent is removed through
four overflow channels in the east bank and
the recirculated flow is drawn from the
southeast corner through a channel along
the south edge to the pumping station at the
southwest corner. A pumping capacity of
4500 gallons per minute was provided for
recirculation, (three 1500 gallon per min-
ute pumps) but only one of the three pumps
is operated under normal conditions.
In Table 29, we have listed the BOD
values for the first four years of operation
averaged over each period of six months.
The table shows an obvious improvement
in results, especially in the anaerobic
pond, through the first eighteen months.
This trend actually extended through Octo-
TABLE 29
AVERAGE BOD VALUES
Jan.-
Jul.-
Jan.-
Jul.-
Jan.-
Jul.-
Jan.-
July-
June,
Dec.,
June,
Dec.,
•June,
Dec.,
June,
Dec.,
1956
1956
1957
1957
1958
1958
1959
1959
Raw Waste
1005
1390
1110
1068
1052
1010
879
1250
Anaerobic
Effluent
454
109
55
105
141
83
96
230
Oxidation
Pond
Influent
345
103
95
124
130
63
66
137
Final
Effluent
127
40
46
51
92
61
43
73
84
-------
her, 19570 During November and Decem-
ber, unusually cold weather prevailed and
the efficiency of the process deteriorated
to some extent.
Stream conditions have been entirely sat-
isfactory below our outfall since installa-
tion of these ponds. During periods of low
flow, the stream has a distinct green color
for the first mile or two but no odors have
ever been noted and the color disappears
in a short distance.
Operation is very simple. The only labor
required is the occasional maintenance and
greasing of pumps, cleaning bar screens,
and caring for the grounds. This, of course,
is exclusive of labor for operation of the
primary facilities. Routine analyses have
been continued as a precaution against un-
foreseen difficulties.
pond, but no heat was provided in the oxi-
dation pond.
Excellent results were obtained and for
a small packing operation the method
should be satisfactory. For a large oper-
ation the cost of heating the pond would
probably make other methods more attrac-
tive.
The anaerobic pond has also been applied
at another of our packing plants, located
in North Carolina, as a pretreatment de-
vice. The pond reduces the BOD of the
waste to approximately 100 mg. per liter
before it is discharged to the municipal
plant where it is given final treatment on
trickling filters. In this case also, there
was a gradual improvement in results dur-
ing the first year of operation. Steam is in-
jected as required to maintain a minimum
of 75° F.
SLUDGE ACCUMULATION
The pilot plant experience did not pro-
vide any reliable information as to sludge
accumulation. It was anticipated that sludge
would have to be removed from the anaer-
obic pond upon occasion but not from the
oxidation pond.
After 2 1/2 years, itwas foundnecessary
to remove sludge from the anaerobic pond.
The top level of the sludge layer was about
4 ft. below the surface, and sludge carry-
over appeared certain in a short time. The
surplus sludge was pumped to a nearby
field where it dried without nuisance.
OTHER APPLICATIONS
In further tests, carried out in Iowa, it
was found that the method could be applied
in a fairly severe climate. An underwater
burner was provided to heat the anaerobic
SUMMARY
A two-stage system of ponds has been
applied to the treatment of meat packing
plant wastes. Advantages are low invest-
ment cost, simplicity of operation and pro-
duction of an effluent that is stable without
dilution. The system has been applied in
areas with a mild climate, and its great-
est advantage is for this application, but
it has also been found applicable in rela-
tively severe climates.
BIBLIOGRAPHY
1. Caldwell, D. H. , Sewage Works Jour.,
18, 443-58 (1946)
2. Committee on Sanitary Engineering,
N. R. C., Sewage Works Jour., 18,
1023-6 (1946)
3. Parker, C. D. , Jones, H. L. , and
Taylor, W.S., Sewage and Ind.
Wastes 22, 760-75(1950)
85
-------
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>irwi -/
Lift station
Recirculation line '
Effluent weirs
ANAEROBIC POND
192' x 320' XI41
Vol. 4.6 mil. gal.
FIGURE 9
87
-------
Over Flow
Troughs
Surface area —19.2 acres
Volume - 19,000,000 gals.
Recirculation channel
Pumping station
FIGURE 10
-------
DEVELOPMENT AND ACCEPTANCE OF LAGOONS IN MISSISSIPPI
J. E. Johnston*
From skepticism to enthusiasm --
those four words summarize the sewage
lagoon story in Mississippi. The state
health officer was skeptical when the la-
goon idea -was first presented to him; pro-
fessional engineers in the state were dubi-
ous; municipal officials were likewise
skeptical; and the public in some cases
was almost hostile.
But somehow the lagoon idea as a solu-
tion to the sewage problems in our small
towns had taken hold of us in the Division
of Sanitary Engineering -- things we'd
heard about it and read about it would not
leave us in peace. Like the evangel stirred
by a spirit outside himself, we could not
rest. And I'm here to share our story with
you -- because in introducing the lagoon in
new areas some of you will perhaps en-
counter this same attitude of skepticism
that we had to combat. But my advice to
you is simply this: "Don't give up. " It
won't be easy to hold out, but on your side
will be two unshakable allies: first, the
engineering and chemical principles in-
volved; and second, the proven experience
of the workability and practicality of the
lagoons. First of all you will need a well-
grounded belief in the idea. I warn you,
however, conviction alone will not be
enough; coupled with it, you'll need tenac-
ity also.
As you know, Mississippi has been an
agricultural state with most of the popula-
tion living on farms and a comparatively
few people living in the approximately 270
towns. With the economy of the state
geared to agriculture as it had long been,
there had been little need for larger cen-
ters of population. But with the develop-
ment of the industrial programs of the
state and the mechanization of farm oper-
ations in the last two decades, our small
towns began to attract more people.
Accordingly, as the towns began to grow,
there was an increased need for sewage
facilities.
In 1955 in Mississippi, there were only
some 24 municipalities with conventional
sewage treatment plants. To make matters
worse, most of these were not operated
efficiently. A number of towns had sewage
collecting systems, but discharged raw
sewage or septic tank effluent into streams-
some of which did not have sufficient
flow for adequate dilution. This was the
condition that confronted us when I became
Director of Sanitary Engineering of the
State Board of Health.
For a number of years we had been
aware of the use of lagoons, but gave them
little consideration until the Dakotas began
to use them so effectively. We learned of
the good results of the Dakotas' lagoons
when we began to search for an answer to
the ever-increasing problem of sewage
treatment for small municipalities. As we
discussed their use in Mississippi, first in
an almost joking manner, our interests
grew. After it became evident that lagoons
might be the answer to our problems, we
began to seriously study all available in-
formation - and then to seriously talk la-
goons. In professional engineering circles,
instead of encouraging us, practicing engi-
neers tried to throw cold water on us.
Some even went so far as to come to me,
or send my friends to me, with the warning,
"You're going to get in trouble. "
However, obsessed with the idea that the
lagoon held the answer to many of our
acute sewage problems and our responsi-
bility in doing something about it, we re-
quested the Public Health Service to send
to Mississippi someone -who was thoroughly
familiar with the stabilization ponds to dis-
cuss them with us. Two specialists came
to our state on January 25, 1956 -- W. W.
Towne, Chief of Water Pollution Control
of the Robert A. Taft Sanitary Engineering
Center (whom you heard yesterday), and
L. A. Young, Associate Regional Engineer
of Public Health Service, Atlanta. After
the assurance of these two experts that the
"Director, Sanitary Engineering, Mississippi State Board of Health, Jackson, Mississippi.
89
-------
ponds would probably work better in Mis-
sissippi than in the mid-western states
where they freeze over in winter, our en-
thusiasm rose. But even these specialists
could not completely dispel the skepticism
of the state health officer. When he was
told that a hurried call had been issued for
professional engineers in our capital city
and vicinity to come to hear the story the
Public Health Service specialists had to
tell, he said: "I hope you don't get the
BoarcLolJHealth in trouble. "
Thirteen engineers and chemists an-
swered the call; and to a man they became
not only interested, but most of them en-
thusiastic about the possibilities of the la-
goon in our state. At the close of the meet-
ing, they suggested that I go to Missouri
and see the lagoons in operation. Even
though the state health officer did not ap-
prove my going, not to be deterred, early
in March after the ice had melted, I went
to Missouri sub rosa. I never shall forget
the courtesies of Albert Happy and his
staff, Glen Hopkins, and Joe Neel. Every-
thing I saw in Montgomery City, Paris,
Perry and the Kansas City area exceeded
my expectation. Convinced that the State
Board of Health should recommend the la-
goon, I turned homeward with my mind
made up and a jug of lagoon water in my
car! That jug of water was more convinc-
ing than words.
Recommendation of the lagoon by the
State Board of Health was forthcoming. The
design criteria developed in the mid-west
were adopted by our agency, with the ex-
ception of the loading factor which was set
at 35 pounds of BOD per acre. All engi-
neers concerned with this type of work
were contacted and our design criteria
discussed with them.
Our first target was Prentiss, a fast-
developing town in South Mississippi. The
main part of that town was served by an
Imhoff tank, which was over-loaded and
very poorly maintained. The western sec-
tion was developing and needed service,
but a pumping station would be required.
Then it was that the consulting engineer,
in cooperation with the State Board of
Health, in conference with the city officials
convinced them that the lagoon could best
solve their sewage oroblem.
The Prentiss lagoon was put in operation
on October 1, 1956. Never shall I forget
the day I took the state health officer down
to see this "curiosity. " On the trip was
also the assistant health officer, who is
now state health officer and supporting the
program with a great deal of enthusiasm.
We had hardly gotten outside the city limits
of our 60-mile trip when they began to rib
me, saying they could already smell the la-
goon. I took the ribbing of my two superi-
ors as long as I could and said, "All right,
gentlemen, just let up until we get there.
If there's any sewage odor at all from the
lagoon, the drinks are on me. " When we
got to the site, I took a bucket and caught
it about half full of the effluent from the la-
goon and handed it to the state health offi-
cer. He sloshed the -water around, stuck
his nose in the bucket, sniffed and sniffed
again. "I'll buy the drinks, " he said, the
last vestige of skepticism gone !
Continuously for almost four years now
this lagoon has been in operation. What has
been its operational history? How has it
been accepted by the people? To get the
answer let me quote from a recent report
to us by the mayor of the town:
"I am happy to inform you that it is doing
a perfect job. It has been in operation near-
ly four years and has done better this year
that it did the first year, even tho it has
had a small increase in load. I can safely
say that for a small town where land is
reasonable, that this is the best solution,
as the cost of construction is very reason-
able.
"We have approximately 400 people per
acre and it is doing perfectly, other than
just a little floating matter on top of the
water. You can hardly recognize it as being
anything but a fish pond since it doesn't
have any odor at all - in fact, there are
millions of small fish in it. "
But back to the development of the lagoon
in Mississippi. From near and far came
consulting engineers, city officials, devel-
opers, and university professors to see
the Prentiss lagoon - the first sewage la-
goon to be constructed in the southeast.
They came from Florida, Georgia, Ala-
bama, South Carolina, Tennessee, Louisi-
ana, Arkansas, and Virginia. Requests be-
gan to come from city officials and civic
clubs for us to talk to them about lagoons.
90
-------
Even though the State Board of Health
has promoted the lagoons by all mass
media available - the press, television,
exhibits, and state-level meetings, from
the very beginning the decision was made
to let the promotion program on the local
level be through the practicing consulting
engineer. We declined to accept invitations
to discuss lagoons with any local group un-
less the invitation came through an engi-
neer. This decision, wise as it was, had a
two-fold basis: first, we wanted to keep the
program in the hands of the engineers; and
second, our staff was too limited to spend
time providing programs for some civic
club. If the municipality was interested
enough to employ an engineer, we felt that
it meant business and we went early and
late from one side of the state to the other
to talk lagoons. The wisdom of our deci-
sion to work through the practicing engi-
neers has time and again been demon-
strated; it is also substantiated by a letter
that came to our office recently from
Eugene Thomas, President of the Mis-
sissippi Society of Professional Engineers:
"It has been my privilege since 1956 to
follow the development of sewage lagoons
in Mississippi, and since I believe this
development has made a real contribution
toward the general improvement of sani-
tary conditions in the smaller communities,
I would like to congratulate you on the man-
ner in which your office has handled this
relatively new idea ir our State.
"Your splendid cooperation with the prac-
ticing engineers of Mississippi is something
that every member of the profession appre-
ciates, and I feel that the contribution made
by your office in improving conditions
throughout the State is worthy of continued
confidence. I know for a fact that you have
in all cases worked through the engineering
profession in this matter rather than
through other local officials.
"This is an approach which I feel is
fitting and proper and which not only pro-
vides an opportunity for engineers to partic-
ipate in these developments, but also con-
tributes greatly to an orderly method of
community improvement.
"If there is anything the Society can do to
assist you in the important work handled by
your office, I am sure we will be most
happy to oblige. "
In less than a year after the first lagoon
began operation, five other towns had con-
structed them; and today there are over 60
lagoons in operation and 25 under construc-
tion or being planned by muncipalities and
institutions.
A year after the first sewage lagoon was
constructed the lagoon program was "on
the road. " Skepticism was giving way to
enthusiasm. Private developers and
schools wanted to use them. But ever
cautious, the State Board of Health with-
held approval in such places because we
did not want the program 'to get out of hand
and have some installations that might pos-
sibly give the program a "black eye. "
However, after a demanding letter from
the State Superintendent of Education to
permit the use of lagoons in rural schools
and a promise from him that his staff
would give full cooperation in maintaining
them, especially by maintaining a satisfac-
tory water level during the summer months,
public health approval was given. Ten
schools are now using sewage lagoons.
Two years ago we began approving them
for private developments, such as subdivi-
sions. We now have twelve such develop-
ments using them.
The developers of Skyway Hills, across
the river from Mississippi's capitol city,
says that their entire staff takes pride in
being the first in the state to provide a la-
goon. From the builder's viewpoint they
cite the following advantages of the lagoon:
"The fact that our subdivision has this
type of sewage system has been the main
feature of our sales campaign and our sales
campaign has been most effective. "
The developers of McLaurin Heights, a
subdivision in Rankin County, wrote us on
recent date:
"We wish to express our complete satis-
faction in regard to the lagoon system of
sanitary sewerage disposal. Before a
sewerage system was installed in McLaurin
Heights Subdivision, Rankin County, Mis-
sissippi, approximately 50% (in numbers)
and 75% (in cost) of our warranty com-
plaints were due to septic tanks. Although
we exhausted every known means of trying
to remedy septic tank malfunctions before
91
-------
the end of the one year warranty period,
still there were several septic tank systems
that were not properly functioning, which of
course left dissatisfaction in those house
purchasers.
"We have found, although the lagoon
type sewerage system takes a great deal
larger initial investment, that by the time
a subdivision is 'built out, ' the average
cost per house is less than the original in-
stallation cost of a septic tank system.
"We appreciate the assistance given to
us by the Health Department and the for-
ward looking approach of the trial of these
lagoon systems which will greatly aid
developers, builders and home owners in
outlying areas. "
Mr. J. W. Underwood of Jackson states:
"The lagoon is a most satisfactory sewer-
are treatment method. ... In the instance
of our 700 home Canton Avenue Estates,
we abandoned a conventional mechanical
treatment plant that was only about 5 years
old and installed lagoons to treat the sewer-
age for the then existing houses as well as
future ones. It has definitely been more
economical for us to do this. "
I would not mislead you into believing
that the acceptance of the lagoon in Mis-
sissippi came "over night." Acceptability
of the lagoon has been a developing attitude
that has increased steadily through the last
five years. Consulting engineers, equip-
ment manufacturers, city officials,
financial institutions, and finally the gen-
eral public, although doubtful at first, have
come to accept lagoons with enthusiasm.
To illustrate this general acceptance, I
would like to read some statements taken
from letters we have received in our off ice:
W. E. Johnson, Consulting Engineer,
Jackson, Mississippi, wrote: "Without any
reservation, I endorse and recommend the
lagoon treatment where possible."
James F. Smith, Mayor, Wiggins,
Mississippi, said in part: "The lakes are
placid and pleasing to the eye; they are
habitats for water fowl.. . . The people of
the Town are pleased with them. "
H. M. Ludlow, Manufacturer's Repre-
sentative, Jackson, Mississippi, says
business has increased, "a good percentage
of which can be directly attributed to sales
created by the installation of the many
Oxidation Ponds in areas and communities
who otherwise were financially unable to
purchase other types, or mechanically
operated Treatment Plants. "
From the Rankin County Bank, Presi-
dent J. C. Murray, -who financed some of
the developers in this county using lagoons,
wrote of the successful operation of sev-
eral lagoons in the county, and said: "We
much prefer to make loans on property
having a sewer system than on property
with septic tanks. . . . We believe that a
sewer system with a lagoon or lagoons is
as good as one with a treating plant, and
we do not hesitate to recommend this type
of sewer system. "
From the Town ot .Bay Springs, after
over three years of experience with a la-
goon, Mayor S. F. Thigpen, Jr. wrote:
"The operation is still perfect and the
cost has not exceeded $60 a year. . . . This
is the only thing public or personal that I
have ever had anything to do with that has
so greatly exceeded what was expected of
it."
From the Hinds County Water Com-
pany, which first entered the sewage busi-
ness three years ago, President Garner
M. Lester wrote: "We now operate three
lagoons. . . . Since this was our first ven-
ture into the use oŁ sewage disposal units
of this kind, we have watched the opera-
tion very carefully. Few of our customers
and friends had ever heard of, let alone
seen, a lagoon and naturally they were
skeptical. They have operated so success-
fully that now uncertainty has turned into
confidence. . . . We thought you would be
interested in our operations since you
worked so closely with us in the begin-
ning. ..."
From the Town of Crenshaw, three
weeks after hook-ups were made to the
lagoon, Mayor C. B. Goodwin, reported
to us: "As you know, our Town being in
the Mississippi Delta is very flat, and
those homes which have been connected
for only a short time have eliminated the
water soaked conditions of their yards
and water filled ditches of the foul polluted
excess water from the old septic tanks.
We wish to thank you at this time for your
92
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aid in helping the Town of Crenshaw com-
plete such a needed and valuable project
for the community. "
From the Town of Fayette after two
years' use of the lagoon, R. J. Allen,
Mayor, and B. J. Scarborough, Sanitation
Committee Chairman, wrote: "We have
encountered no defects in or dissatisfac-
tion with the lagoon system and .... re-
commend this type system without reser-
vations. "
From J. B. Bell, the Mayor of Her-
nando, where a lagoon was constructed in
1957 to replace an outdated and inadequate
Imhoff tank: "The governing authorities and
the residents of Hernando have been very
pleased with the operation of their treat-
ment lagoon, and the Town has on the
drawing boards new plans for three addi-
tional sewage treatment lagoons. . . . The
lagoon in operation has been perfectly sat-
isfactory in all respects. ... The Town's
maintenance has been at a minimum con-
sisting so far only of keeping the grass
cut. . .. We had a good crop of fish coming
on in the lagoon, but a cotton dusting
plane got loose over it and we lost our
crop of fish. "
From Houston where a 15-acre lagoon
has been in operation since August, 1957,
Mayor J. H. Miller wrote: "It has proven
very satisfactory since the first day of
operation, and looks more like a recrea-
tional place than a disposal unit. "
From the City of Starkville, the home of
Mississippi State University, Mayor Hay-
den H. Reynolds stated: "We put two
twenty-five (25) acre cells into service in
September 1959 and they have given us
satisfaction far beyond expectation. We
seem to be getting 100% treatment from
them and are highly pleased with their
operation. . .. The general public who have
visited the project have accepted them very
enthusiastically and feel they are a credit
to our city. College boys from Mississippi
State University say it is a hunter's para-
dise "
From the Town of Poplarville, Mayor
Pat Hyde reported: "We have had our
sewer lagoon in operationfor approximately
eighteen months and have found it to be the
answer to the sewage problem in the smaller
cities and towns. . . . When we first talked
to our people about a lagoon, they were
a little skeptical as it was something that
they weren't familiar with. I was about as
skeptical as anyone in town. ..."
From the City of Aberdeen, one week
after two lagoons were put in operation,
Mayor George W. Howell, Jr. , wrote us:
"The City of Aberdeen has been dumping
its sewage into the Tombigbee River for
sixty years or more; and, this practice was
stopped for the first time when the lagoons
were put into use. This fact alone made
the lagoons popular from the very start
with the general public. Property owners
have cooperated, and we had no difficulty
in securing land for the lagoons where we
wanted them located and for very reason-
able prices.
"Since we quit dumping sewage in the
river, a group of sports enthusiasts here
have built a boat landing on the river just
off East Commerce Street and have gone
in for boating. ..."
In speaking of the development of la-
goons in our state, we must not fail to
point out that two experimental sewage la-
goons were put into operation on the cam-
pus at Mississippi State University on
August 15, 1958, in cooperation with the
State Board of Health. Experiments, in
the main, have sought the answers to
three problems: (1) How to control blue-
green algae; (2) What is the optimum depth;
(3) What is the optimum surface loading.
While a great deal of data have been col-
lected, no definite conclusions have been
reached. The micro-biology department
has also been interested in these experi-
mental lagoons and has demonstrated that
organisms of the genus Salmonella can
survive passage through the lagoon.
The only trouble that we have encountered
in lagoon operational experience in our
state has been the development of blue-
green algae in extremely hot weather. As
you know, dead blue-green algae give off a
distinct pigpen odor. The first complaint
of odor to reach us came in July 1958 from
a two-year old lagoon. The Public Health
Service office in Cincinnati answered bur
emergency call by sending in a specialist
the next day by plane, who identified the
mass of dead blue-green algae as the mis-
chief maker. However, it soon disappeared
and there was no further trouble that sea-
son.
93
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The following summer, under the heat
of July's sun, the same lagoon developed
the same pigpen odor, as well as two other
lagoons in different parts of the state. The
first complaint came from the mayor of a
nearby town, and it was suggested to him
over the telephone that he have the scum
broken up with long poles or boards and
that it might settle out. When I left the
office that afternoon, I drove to the town to
see if beating up the scum was getting re-
sults. I soon saw that this method was too
slow to be successful. I had an inspiration:
Why not put a boat with outboard motor on
the lagoon to beat up the mass? This we
did, and in a very short time the lagoon
surface was clear and the pigpen odor disap-
peared. During this summer several lagoons
have developed the pigpen odor; and in
each case a boat and outboard motor have
soon had the condition under control.
The question of mosquito breeding kept
cropping up as we talked with people about
lagoons. But apparently Mississippi la-
goons are not a very suitable place for
mosquitoes to breed. In July and in Sep-
tember of 1958 Leslie D. Beadle, Chief
Biologist, Water Resources Activities,
Public Health Service, (who will be heard
later), made a mosquito survey of nine of
our lagoons that had been in operation for
the second summer. Mosquito breeding
was detected only in the Prentiss lagoon.
This lagoon showed moderate breeding in
July and light breeding in September,
while the swampy area near the lagoon
showed very heavy breeding. To date we
have not had a single complaint about mos-
quito breeding in lagoons.
What, you might ask, has been the total
effect of the development and acceptance
of lagoons to date in Mississippi? And
•what is the future challenge to us ?
These questions might best be answered
by a letter that came to our state health
officer a few weeks ago. It was from a
man many of you know - Sam A. Thompson,
Chairman of the Board of Water Commis-
sioners of the State of Mississippi. He
explained that he had just seen a newspap-
er clipping showing a picture of one of the
state's latest sewage lagoons and was
prompted to write a letter to the State
Board of Health, which said in part:
"Mississippians have just cause to be
proud of the leadership role that your
agency has assumed in the program that is
doing so much to upgrade the quality of the
surface waters of our State.
"Since your Division of Sanitary Engi-
neering introduced the sewage lagoons to
Mississippi, the many towns that have tak-
en advantage of the program have practi-
cally eliminated the once serious pollution
problem in their vicinities.
"If you can keep up this good work for a
few more years, our State will be able to
make the maximum use of its water re-
sources. "
Our agency is resolute. In the days
ahead with the special assistance of Public
Health Service and through the stimulation
from the pooling of ideas and experiences
in groups such as this, -we shall go forward.
94
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USE OF SEWAGE PONDS IN ALBERTA, CANADA
By
H. L. Hogge and, S. L. Dobko*
The number of sewage ponds in use in
Alberta has grown from one in 1947 to 114
in I960. This extensive use is attributed to
three main factors, viz. low construction
and operating costs, effective treatment of
sewage and the storage capacity which per-
mits the effluent to be released at an ap-
propriate time.
The design and use of ponds in Alberta is
influenced to some extent by the climatic
conditions experienced. Alberta is the most
westerly of the three "prairie" provinces
of Canada. The north and south boundaries
are the 60th and 49th parallels of latitude
respectively; the east boundary is the 110th
meridian and the western one is the 120th
meridian and in the south part the "Conti-
nental Divide" in the Rocky Mountains. The
mountains to the west result in a relatively
dry climate with the average annual pre-
cipitation ranging from 10 to 20 inches for
most areas. The northerly position of the
province means that winter temperatures
are cold. The January average is 0 to 5
degrees Fahrenheit for all but extreme
northern areas where it is 0 to minus 15
degrees. This results in a thick ice cover
on sewage ponds during the winter and this,
together with snow, excludes the sunlight
necessary for oxygen production by the
algae. Summer temperatures are moderate
with the July average ranging from 55 to 65
degrees F. Winds are of a relatively uni-
form annual velocity of about 10 m. p. h. ,
although the stronger winds are from the
south west in southern areas and northwest
to north in the northerly areas. Soil condi-
tions are quite varied ranging from heavy
clays to sandy and sandy silt. Percolation
from the ponds is appreciable in only a few
locations.
The population of Alberta was 1, 220, 611
in 1959 with 66% of the people residing in
incorporated urban centres and 34% in
rural areas. Some 96% of the urban popu-
lation have public sewerage systems avail-
able through 187 systems. As mentioned
above 114 of the sewerage systems use
sewage ponds for their sewage disposal
facilities. These are relatively recent in-
stallations, all within the past 15 years,
and have been a factor in making sewerage
systems possible, particularly for those
communities not located near a river or
lake.
The design and use of the ponds has
undergone a number of changes which may
be of interest to others.
The first ones were built mainly for
storage purposes and were designed to
store the sewage for one year. They were
preceded by either a Septic tank or an Im-
hoff tank to remove solids and the accumu-
lated effluent was released in the spring
•with the annual run-off. At this time of
year there was a maximum amount of dilu-
tion to carry away the effluent and also it
is before the farmers are working the
fields crossed by the small drainage
courses.
A second phase was the use of open pits,
having a detention time of one to two weeks
to take the place of the primary sewage
treatment plants both in preceding the stor-
age ponds and also as the only treatment
where primary treatment was all that was
necessary.
A third phase in the use of sewage ponds
was the elimination of pretreatment units
preceding the storage ponds and using only
the storage ponds both for treatment and
storage. These were mainly constructed in
single units even as large as thirty and fifty
acres.
'Respectively Director Division of Sanitary Engineering and Engineer, Sewage Pond Study Project Division of Sanitary Engineer,
Alberta Department of Public Health.
95
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The fourth phase that we are now start-
ing in Alberta, and which we believe will
be of most interest, places emphasis on
the treatment efficiency of the short deten-
tion ponds and the added advantages of hav-
ing the long detention ponds constructed in
units arranged for series flow of the sew-
age. Very briefly, we are recommending
the following type of pond system where
complete sewage treatment and also inter-
mittent release of the effluent is necessary:
1. Short Detention Ponds - Four ponds
with a detention time of two to five days
in each.
2. Long Detention Ponds - Two ponds with
a detention time of three or six months
in each.
This latest type of ponding system has
been adopted this year on the basis of a two
year study of the operations of different
types of ponds. The study was undertaken
as a research project financed by the Gov-
ernment of Canada, Department of Public
Health in co-operation with the Department
of Lands and Forests and the University of
Alberta. A chemical engineer of the De-
partment of Health made the field observa-
tions, collected all samples and analyzed
the samples for physical, chemical and
B. O. D. characteristics. The analyses were
made in the Department of Health's Pollu-
tion Control Laboratory. Methods of analy-
sis were those outlined in the 10th Edition
of "Standard Methods for the Analysis of
Water, Sewage and Industrial Wastes. "A
master's student in microbiology at the
university under the direction of the Bac-
teriology Department made analysis for
total aerobic and anaerobic bacteria and
also for coliforms and algae. At this time,
the master's thesis and the analysis of the
data are incomplete.
The ponds selected for detailed study
were those within 100 miles of Edmonton to
enable sampling and analysis to be carried
out in the same day. Also these ponds were
representative of a variety of loading and
design features. Five ponds were sampled
approximately once a month for a 12 month
period, a 24 hour composite of raw sewage
made flow rates measured, and the chemical
analysis of the community water supply ob-
tained.
The statistics respecting loading and re-
moval of B. O. D. and ammonia are quite
interesting and are noted below in Table 30.
The long detention ponds of Holden and
Lacombe, which are constructed in a single
unit, gave removals of slightly better than
80% of the B. O. D. and 90% of the ammonia
during the summer. In winter time the
treatment starts to deteriorate soon after
the ice cover forms, and remains at a
lower level until spring. These two ponds
are quite similar. However, the B. O. D.
reductions in the winter were consistently
different during both winters. The B. O. D.
loading for Lacombe is slightly higher but
would not be expected to be significant.
The Bruderheim pond operated poorly
during the period of study and appeared to
be affected by the wastes from the local
cheese factory. The observed B. O. D. of
the raw sewage was 394. However the
summer B. O. D. of the pond average 465
and in the winter was 880 p. p. m. A Com-
putation of the B. O. D. in the cheese wash-
ings for the plant indicated the average
B. O. D. of the towns sewage would be in-
creased 632 p. p. m. which would explain,
at least to some extent, the high B. O. D. 's
observed in the pond and most likely the
poor functioning of the pond.
The ponds at Drayton Valley are con-
structed in three units and worked very
efficiently during the summer. In addition
to the B. O. D. and ammonia reductions the
removal of coliforms was very good and the
effluent in the third pond was clear. The
treatment deteriorated during the winter
season and remained at the lower level
until spring.
The Short Detention Pond studied in de-
tail was at Stony Plain. This system worked
at about the same level throughout the year.
The B.O. D. reduction of 70% particularly
during the winter time is quite good and the
installation is very inexpensive. This sys-
tem was expanded to include a storage pond
in 1959 and this appeared to work very well
but sufficient tests were not carried out to
determine it's efficiency.
The "Short Detention Ponds" were of
particular interest to us because of their
efficiency during the winter and we made
surveys of five other installations. The
statistics on these are included in 30A.
These ponds were all of the single unit
type and are therefore not directly compa-
rable to the Stony Plain installation, except
to the first of the three units at Stony Plain.
96
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97
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Our tests showed a B. O.D. removal of
33% in the first of the three units here and
a reduction over the second-two units at
54%, giving the overall reduction of 70%.
Tests were not made across the second or
third units separately, however if one as-
sumed the same reduction of B. O. D.
across each one, the individual B. O. D. re-
ductions would be 32%. This suggests a
B. O. D. reduction of 30 to 35% for each of
the one day detention units operated in
series and for purposes of comparing the
Stony Plain ponds to those listed in Table
30A, the B.O.D. reduction would be 33%.
There appears to be a definite relation-
ship between the detention time in days and
the percentage of B. O. D. removals in
these Short Detention Ponds, with the ex-
ception of the Two Hills installation. This
exception is attributed to the unusual depth
of the pond which was 18 feet compared to
depths of 4 to 6 feet in the others. The
other installations would indicate an op-
timum detention time of about five days, at
which a B.O.D. reduction of some fifty
percent might be expected. The B.O.D.
loading on this basis would be 990 Ibs/
acre/day or 198 Ibs/acre ft./day for a
sewage flow of 100,000 gallons per day at a
B.O.D. of 350 p. p.m. The upper limit for
B.O.D. loading is considerably higher than
this as the first Stony Plain pond was oper-
ating quite satisfactorily at a loading of
4920 Ibs/acre/day or 984 Ibs/acre ft./day.
Also, the biological processes involved
here are basically anaerobic and therefore,
the operation might be compared to that in
a sludge digestion tank. The B.O.D. load-
ing on the digestion tank, assuming 30% of
0. 26 Ibs B. O. D. per person per day, a
tank capacity of 3 cu. ft. per person and a
holding time of six months, would be 5, 900
Ibs/acre foot/day or six times that in the
Stony Plain first pond. Practical consider-
ations would seem to rule out loadings of
greater than about 5, 000 Ibs. B. O. D. /
acre/day as the build up of sludge -would be
such that cleaning would be required more
than once a year to avoid serious flow
channelling and exposed sludge solids.
With respect to other aspects of the oper-
ation of the short detention ponds, the fol-
lowing observations were made:
(a) Odor Nuisance: odors were very light
and not noticeable more than a
hundred feet away when the pond was
working properly as at Stony Plain.
Some odor problem existed at three
ponds and this was attributed to a
different reason in each case. One
had a detention time of 1 1 days, which
is considered too long, another re-
ceived some cheese plant waste and
the third was treating sewage with a
sulfate content of 700 p. p. m.
(b) Ammonia Reduction: no significant
change from that of the raw sewage.
(c) Phosphate Reduction: very little.
(d) Coliform Bacteria Removal: Some,
but not of practical significance.
The Long Detention Ponds which were
studied all received raw sewage and had
Detention Times in the range of 100 to 300
days. In operation they were all similar
during the summer time and the following
general observations were found to be in-
dicative of good operation:
(a) pH - in the range of 8 to 10.
(b) Color - Green - due to algae content.
(c) Odor - no detectable odor in the area
surrounding the ponds.
The treatment efficiency of the ponds
was gauged mainly by the reduction of
B.O.D., ammonia and of coliforms. The
single cell ponds gave B. O. D, reductions
of about 80%, and reduction of coliforms
and ammonia of about 90%. The Drayton
Valley pond is operated as a series of three
units and gave B. O. D. reduction of about
90%, ammonia reduction of some 90% and
almost complete removal of the coliform
bacteria. In addition the effluent from the
third pond was very clear and had a low
phosphate and detergent content.
The B.O.D. loading of the two single unit
ponds was about 20 Ibs/acre/day while in
the first unit of the three unit pond it was
about 80 Ibs/acre/day. While this higher
loading did not seem to upset the operation
unduly, it was noted that the B.O.D. reduc-
tion was only 73%. This and the possible
adverse effect of slightly higher than
normal amounts of industrial wastes in
some communities, indicated to us that a
98
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maximum design loading of 60 Ibs of BOD/
acre/day was desirable.
Winter time operation of the Long De-
tention Ponds is markedly inferior to that
realized in the summer. The reduced tem-
peratures of the liquid, 32 deg. F. , as
compared to summer temperatures of 50
to 70 degrees, no doubt has some effect
but this may not be significant in view of
the long detention times involved. The
most important factor is felt to be the
presence of the ice cover and a light insu-
lating layer of snow - which reduces the
oxygen producing capabilities of the algae
to the point where there is a deficiency of
oxygen, in the pond liquid. Subsequently
anaerobic decomposition processes start
to predominate and in a manner which
generates odorous materials. Our obser-
vations of the sulfate content of the liquid
during the winter showed a definite reduc-
tion in only two of the four studied and an
odor of hydrogen sulfide was noted only in
those two. These odors are not noticed in
the surrounding areas until the ice starts
to melt in the spring, however they con-
tinue for a period of from 2 to 6 weeks
each spring and this makes it desirable to
locate the ponds at least a half mile from
urban areas and one quarter of a mile from
individual residences.
There has been no particular effort made
by any municipality to minimize the spring
time odors by chemical treatment up to
this time, possibly because there have been
few complaints due to the pond locations.
The Department of Health has done some
limited tests on one quart samples in the
lab and also placed in the berms of the
pond but the results were not conclusive.
The use of the short detention ponds pre-
ceding the long detention ponds may give an
improvement by reducing the carbonaceous
organic loading of the ponds. At this time
there is only one pond system of this type
in operation and the limited observations
indicate that there is an appreciable im-
provement but some odors are generated
in the latter part of the winter. Similarly
it was noted at Drayton Valley that the
odors disappeared from the third unit in a
2 week period while it took four weeks for
the odors to disappear from the first
unit.
The cost of constructing sewage ponds in
Alberta generally range from $800. 00 to
$1200.00 per acre, exclusive of land costs.
Agricultural land for the ponds ranges
from $150. to $300. per acre for the small
to medium sized communities; for cities
of 50, 000 population and higher, the land
costs would be up to $1, 000. per acre.
The contract for a new pond system for a
community of 2, 000 people was awarded
this spring at a price of $30, 800.00. The
size of this pond was 31 acres including a
strip of 100 feet outside the toe of the
berms. This is a cost of $994. 00 per acre
and it is estimated that the land cost would
be $200. 00 per acre giving a total cost of
$1200.00 per acre or a sum total cost of
$37, 200.00 to the town. The per capita
cost for the present 2, 000 population is
$18. 60 and for the design population of
3, 000 it is $12.40 per capita. Some of the
design data for this pond are as follows:
Present Sewage Flow - 50 g.pc.d. for
2000 - 100,000
g.p.d.
Short Detention Ponds- 4 @ 4. 5 days deten-
tion each.
- depth - 10 ft.
- inside berm slope
3:1
- outside " "
2:1
- Connecting piping
will permit use of
4 or 3 of the units
in series,
Long Detention Ponds - 2 - 1 @ 33 days
detention with an
operating depth of
6 feet.
- 1 @ 296 days deten-
tion with an operat-
ing depth of 7. 5
feet.
- Berm slopes of 4:1
and 3:1 inside and
outside respec-
tively.
99
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SUMMARY
Sewage ponds are used extensively in
Alberta and are effective in the treatment
of sewage and also as storage facilities to
enable controlled release of the sewage.
Short Detention ponds with a detention time
of one to five days are effective in so far
as B. O. D. removal is concerned and oper-
ate efficiently in both winter and summer
seasons. These are increasingly effective
when used as three or four separate units
operating in series.
Long Detention ponds having a B. O. D.
loading of not more than 60 Ibs. of B. O. D. /
acre/day are effective during the summer
season particularly if constructed to oper-
ate in a series of two or more units. There
would appear to be very definite advantages
in having the short Detention Ponds precede
the Long Detention Ponds. With where Long
Detention Ponds in series, or two Long
Detention Ponds in series, preceded by the
Short Detention Ponds almost 100% treat-
ment of the sewage would be expected dur-
ing the summer season.
Winter time operation of the Long Deten-
tion Ponds is not as effective and some
odors are experienced in the spring for 2
to 6 weeks after the ice starts to melt.
These odors make it desirable to locate
the ponds one half mile from urban areas
and one quarter mile from individual resi-
dences but has not been a serious problem.
It is expected that sewage ponds will
continue to be widely used by Alberta
communities, particularly those with popu-
lations of less than 10, 000 to 20, 000 people.
The Short Detention Ponds may prove to be
useful and economic for even the larger
cities.
Local health hazards have not been noted.
The growth of flies or mosquitoes has not
been a problem and special control meas-
ures have not been necessary except to con-
struct in a manner which avoids shallow
areas and to keep grass and weeds under
control during operation.
The use of sewage pond water for irriga-
tion or other purposes has been very limited
to this time. One community of 3, 000
people which is disposing of the accumu-
lated water by irrigating alfalfa fields is
the only one making definite use of the
water.
ACKNOWLEDGEMENTS
The kind permission of the Honorable J.
Donovan Ross, M. D. , Minister of Health,
Government of Alberta, to prepare and
present this paper is gratefully acknowl-
edged. The financial assistance of the Gov-
ernment of Canada, Department of National
Health and Welfare, for the research study
of the Sewage Ponds is also gratefully ac-
knowledged.
100
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SEWAGE LAGOONS AND MOSQUITO PROBLEMS
by
Leslie D. Beadle and John A. Rowe*
The question of the mosquito breeding
propensities of sewage lagoons has been
raised frequently. In at least 10 States,
either State or Federal personnel have
made observations on this problem.
Interest in these installations has been
motivated by the mosquito annoyance prob-
lem and the generalized encephalitis threat
in the western half of the country. It is well
established that mosquito vectors of St.
Louis encephalitis and western encephalitis
are produced in large numbers in almost
any accumulation of water, but especially
in waters with high organic content. Sewage
lagoons are of particular concern since
they are usually located within mosquito
flight range of a town.
The purpose of this paper is to bring to-
gether a summary of existing data on mos-
quito production in sewage lagoons. Our
definition of a sewage lagoon is a man-
made structure of controlled size and shape
that is designed to receive raw or settled
domestic sewage.
There have been no extensive investiga-
tions on this problem. Specific observa-
tions have been published from Texas --
Eads (1); Eads and Menzies (Z); Harmston
ejt al. (3); the Dakotas -- Beadle and Harms -
ton (4); and Nebraska -- Rapp (5). Unpub-
lished data are available from Arizona,
Georgia, Mississippi, Missouri, Okla-
homa, and Tennessee. Experiences per-
taining to mosquito control on an oxidation
pond in California have been described by
Sampson (6).
Table 31 summarizes entomological data
for sewage lagoons in 10 States located in
3 geographical regions. The predominant
species found in the lagoons were Culex
tarsalis in the Midwest and C. tarsalis and
Culex pipiens (quinquefasciatus) in the
Southwest. Up to the present, only light
production of mosquitoes has been observed
in southeastern installations.
Additional species of mosquitoes taken
in sparse numbers from the sewage lagoons
include the following: Aedes campestris
(North Dakota), Aedes dorsalis (North Da-
kota and South Dakota), Aedes vexans (Ari-
zona and Nebraska), Anopheles quadrima-
culatus (Missouri and Tennessee), Culex
erraticus (Mississippi and Tennessee),
Culex restuans (Nebraska and North Da-
kota), Culex salinarius (Georgia andTexas)
Culex thriambus (Texas), Culiseta inornata
(Nebraska and Oklahoma), and Psorophora
confinnis (Arizona).
The intensity of mosquito production in
the lagoons surveyed has varied directly
with the amount of weed growth. Those
shallow ponds that have contained abundant
emergent vegetation invariably produce
tremendous numbers. Other ponds where
such vegetation is marginal may produce
large numbers along the peripheral area.
Conversely, ponds free from vegetation
have presented no mosquito problem. There
does not appear to be a correlation between
the oxidizing efficiency of the pond and
mosquito production.
The "weedy" condition in sewage ponds
may be related to several factors, one of
the most important being faulty filling of
the pond. It has been observed in a number
of instances that filling difficulties and the
concomitant shallow weedy conditions are
related to the porous nature of the soil and
the lack of attention to sealing of the pond.
It also has been observed that many •weedy
situations are due to over design. In many
of these cases, ineffective attempts have
been made to establish a functioning pond
by building cells in the bottom. We have the
feeling that many of the earlier ponds were
'Communicable Disease Center, Public Health Service, U. S. Department of Health, Education and Welfare, Atlanta, Georgia.
101
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TABLE 31
SUMMARY OF ENTOMOLOGICAL INSPECTIONS AT SEWAGE LAGOONS IN 10 STATES
State
No. of Ponds
Sampled
Ponds Producing Mosquitoes
Ponds Producing
Number
Percent
Culex
tarsalis
Culex
pipiens*
Midwest
Missouri
Nebraska
North Dakota
South Dakota
Southwest
Arizona
Oklahoma
Texas
Southeast
9
30
12
15
18
35
37
4
15
9
10
10
6
23
44
50
75
67
56
17
62
3
10
9
10
7
2
14
3
2
0
0
8(C.Ł.)
5(0. a.)
17(C.Ł.)
Georgia
Mississippi
Tennessee
3
9
3
1
1
2
33
11
67
0
0
1
0
0
0
*The Culex pipiens complex includes Culex quinquefasciatus (Ł.Ł.)•
too large for the communities that they
served.
In certain communities, it has beennoted
that weed problems in the lagoons have
been minimized because the ponds were
filled with water immediately following
construction; whereas in other communi-
ties that have not utilized the water filling
method but have utilized only sewage flows,
the time required to fill the lagoons has
been much longer and weed growth has been
a problem.
Another problem related to weed control
and to the proper management of the pond
is the lack of outlet structures that permit
complete water level control.
Inadequate lagoon maintenance -- such
as lack of care by the operator of the
lagoon -- is a frequent cause of weed prob-
lems in the lagoon proper or on the banks.
Suggestions for Minimizing Mosquito
Breeding in Sewage Lagoons
Design and construction features
1. The proper size of the lagoon should be
determined carefully. It should not be
too large for the population served.
Provision for multiple lagoons is an
excellent means of allowing for expan-
sion.
2. The lagoon should be constructed so as
to hold water. Artificial sealing with
chemicals, clay, bentonite, or plastic
or asphalt membranes should be used
if necessary.
3. Complete water level control and
drainage structures should be built into
the pond. Such structures facilitate the
control of marginal vegetation by the
use of water level management (draw-
102
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down) coupled with soil sterilants.
Lowering the water level temporarily
also may be used to control mosquito
larvae.
4. The dikes should be of sufficient width
(generally 8 feet) to permit access of
maintenance machinery such as seed
drills, mowers, and larviciding or
herbiciding equipment.
5. The inner bankment slopes should be
relatively steep -- e. g. , 3 or 4 feet
horizontal to 1 vertical.
6. The depth should be as great as possi-
ble for maximum waste treatment.
Depths of over 25 inches will discour-
age the development of cattail and
other emergent plants (7).
7. The lagoon bottom should be cleared of
vegetation prior to filling, and it
should be as level as possible.
8. The lagoon shouldhave a uniform shape
with the inlet near the center of the
pond.
9. The lagoon should be readily acces-
sible. A roadway to the lagoon will en-
courage frequent inspection and facili-
tate movement of maintenance equip-
ment.
10. The lagoon embankments should be
planted with a suitable species of
grass, such as brome. Care shouldbe
taken, however, to avoid species such
as reed canary grass, which may in-
vade water. Fertilization of the dikes
will aid in the development of grasses.
Operational and maintenance features
1. If water is available, immediate filling
of the lagoon to operational level will
discourage the growth of vegetation.
2. All lagoons should receive regular and
frequent observation and maintenance.
Control of vegetation and mosquitoes
should be a regular part of lagoon
maintenance.
3. Undesirable vegetative growth in the
lagoon proper or on the dikes should
be eliminated periodically by mowing
or by use of suitable herbicides. If the
weeds are mowed, care should be
taken to see that the cut-off plants do
not float in the lagoon and provide har-
borage for mosquitoes. The planting of
water-loving plants such as willows or
poplars should be discouraged.
4. Larvicidal measures should be used in
the event that significant mosquito
production takes place in the lagoon.
The following materials have been
used effectively: diesel oil (thinlayer):
1 or 2% oil solution of DDT; BHC dust
(3% gamma isomer); or 2% malathion
emulsion.
jSummary and Conclusions
Present evidence indicates that many
sewage lagoons in the Midwest and South-
west are producing mosquitoes. In many of
these, the numbers of mosquitoes produced
are of real significance. In general, mos-
quito production is directly proportional to
the extent of vegetation (weed growth) in
the lagoons.
Because of the usual proximity of lagoons
to small communities and to residential
areas in metropolitan centers, mosquitoes
produced cause considerable annoyance.
More important than their annoyance is the
fact that the major species found -- Culex
tarsalis and the Culex pipiens complex --
are primary vectors of encephalitis. In
order to protect the public health, large
populations of these species should not be
permitted to occur in areas close to popu-
lated areas.
Certain design and operating features of
lagoons are important to mosquito preven-
tion. Basically, they are features designed
to prevent or minimize weed growth.
There can be no doubt that sewage la -
goons are gaining in popularity throughout
the country, and they should continue to be
developed. It is hoped that health agencies
and other groups concerned with the con-
struction and use of these ponds and par-
ticularly those groups who are charged with
their care will proceed with the develop-
ment and use of ponds in such a manner
that production of mosquito vectors of en-
cephalitis will be minimized.
We would urge health agencies in various
geographical areas to continue making ob-
servations on lagoons and to report the in-
103
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formation so that everyone will benefit by
the findings.
Acknowledgment
The writers are grateful to the following
persons who provided us with unpublished
data from their respective States: G. Allen
Mail and George R. Hayes, Jr. (Arizona);
Clyde F. Fehn (Georgia): LeRoy K.
Rachels and Reuel H. Waldrop (Oklahoma):
James L. Church, Jr. (Tennessee): and
William F. Rapp, Jr. (Nebraska).
1.
2.
References
Eads, R. B. : Vectors of encephalitis,
Texas Health Bull. 9:16-17, June
1956.
Eads, R. B., and Menzies, G. C. :
Texas mosquito problems from a
species standpoint. Mosquito News
188-189, September 1956.
16:
Harmston, F. C., Shultz, G. R. ,
Eads, R. B. , and Menzies, G. C. :
Mosquitoes and encephalitis in the ir-
rigated High Plains of Texas. Public
Health Rep. 71:759-766, August 1956.
Beadle, L. D. , and Harmston, F. C.
Mosquitoes in sewage stabilization
ponds in the Dakotas. Mosquito News
18:293-296, December 1958.
Rapp, W. F. , Jr. : Sewage lagoon
maintenance. Water Pollution J. 32:
660-662, June I960.
Sampson, E. O. : A double duty oxida-
tion pond. Sewage & Industr. Wastes
27:1414, December 1955.
Steenis, J. H. , Smith, L. S., and
Gofer, H. P. : Studies on cattail man-
agement in the Northeast. Trans. NE
Wildlife Conf. 1:149-155, 1958(1959).
104
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LAGOONS FOR HOG FEEDING FLOORS
Ralph L. Ricketts*
Confinement feeding of hogs in Missouri
is gaining in popularity. Probably the big-
gest single job connected with this feeding
is disposal of manure. Our hog feeders are
searching for an answer to this problem.
One solution that offers definite possibili-
ties is the use of lagoons.
A survey made in Missouri indicates that
about 50 lagoons were in use in 1959. One
hundred more are planned for I960. The
size of those constructed range from less
than 10 square feet to 30 square feet per
hog capacity of the feed floor. The average
size is about 15 square feet per head. Most
of the farmers contacted were satisfied
with the performance of the lagoons. Thir-
teen said they were highly pleased and only
two said they were not satisfied with the
units. About one-half were built adjacent
to the feed floor and the remainder at a
distance from the floor with a tile used to
carry the liquid and manure to the lagoon.
About one-third have been in use more than
a year and the remainder in use less than
one year.
A study of the results of this survey plus
conversation with various farmers using
lagoons allows us to develop some tenative
suggestions. We are not, however, either
encouraging or discouraging them at this
time. These suggestions are made to give
assistance to those giving thought to the
installation of one. It is emphasized that
lagoons are experimental and that further
study and research is needed concerning
their design and use.
SIZE: - Minimum of 15 square feet sur-
face area per head capacity of feeding floor.
This will be almost as large as the feed
floor.
DEPTH: - Minimum of 3 feet.
LOCATION: - Most convenient from
standpoint of use is to place adjacent to
the feed floor as shown in Sketch 1. Floor
can be easily cleaned by hosing or scrap-
ing directly into lagoon. Where conditions
are such that adjacent location is not pos-
sible, lagoon may be placed at a distance
from the feed floor and the manure carried
to it by a tile as shown in Sketch 2. How-
ever, more trouble is experienced getting
manure to the lagoon when the tile is used.
Usual way is to build a gutter along the
south side of the feed floor, sloping it to
the center where the tile is located. This
tile carries the manure to the lagoon. Con-
siderable water is necessary to avoid tile
stoppage. Some feeders plug the tile open-
ing until considerable solids and liquids
have accumulated in the gutter. The solids
seem to move through the line better in
larger quantities. The outlet of the tile
should be about 24" above the liquid surface
in the lagoon and about in the center of it.
Tile slop should be about 1/4" per foot and
minimum diameter 6". Eight inch diameter
would be more desirable.
CLEANOUT: - Apparently lagoons do not
have to be cleaned often. Some have been
in use more than a year and have never
been cleaned. Cleaning can probably best
be done by use of liquid manure pump.
Another method is to drain lagoon, then
remove solids with scraper after they have
dried.
WATER: - Lagoons should be kept filled
with water. Where soil conditions are
right, water from the feed floor plus rain
water falling on the feed floor and into the
lagoon is sufficient to keep them filled. No
surface water should be allowed to enter
them except perhaps during the initial fill-
ing period.
ODORS: - Some odors should be expected.
While these are called lagoons, they prob-
ably function more nearly like large open
topped septic tanks. More study is needed
on this point, but if the water basin inwhich
hog wastes are placed operated as a true
lagoon, only oxygen would be released and
•Extension Agricultural Engineer, University of Missouri, Columbia, Missouri.
105
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there would be no odor. However, if we
use the same standards for designing la-
goons for hog wastes as for sewage from
tourist courts, trailer courts, schools,
etc. , a lagoon 1 to 2 acres in size would
be required for 100 hogs. This size would
be impractical in most instances. There
are odors from the feed floor and some ad-
ditional from the lagoon are not objectional
provided they do not become excessive.
Lagoons and hog feeding floors should be
500 feet from the dwelling and preferably
in a direction other than the prevailing
winds.
The hog feeding arrangement shown in
the photograph is one of the best planned
units in Missouri. It is on the Bob Tackett
farm near Warrensburg, Missouri.
The building is 30 feet wide, A 10-foot
wide alley is provided along the north side
of the building interior for access. Size of
the feeding floor is 30 feet by 110 feet.
Twenty feet of the feed floor is under roof
and the remaining 10-foot width is sun pens
along the south side of the building. The
inexpensive shelter gives protection from
wind and snow during the winter months
and provides effective shade during summer
months. Fog spray nozzles are also used
for summer time cooling. Automatic wa-
terers are provided in e?ch pen. Floor
slopes to the front or to the south 1/2" per
foot except in the bedding area along the
back or north side of the pens where the
slope is reduced to 1/8" per foot.
The lagoon is 21 feet by 110 feet. Usu-
ally, manure is pushed into it with a snow
shovel. Sometimes the floor is cleaned by
hosing.
Advantages of the unit may be pointed
out as follows:
1. Original cost is kept low.
2. Labor problem of feeding and care
of hogs is kept to minimum.
3. Fly problem is reduced.
4. There is no mosquito problem.
About the only disadvantage is that odors
are excessive at times during days of high
relative humidity.
106
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- 59
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I
107
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108
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REPORT ON NORTH DAKOTA USE OF SEWAGE STABILIZATION LAGOONS*
by
W. VanHeuvelen*
This year completes a ten-year period
in which lagoons have been used in North
Dakota at an ever-increasing rate and ex-
tensively adopted as the method of munic-
ipal sewage treatment. On July 1, 1950,
there were three sewage lagoons operating
in our state, while this year on July 1,
I960, we find 113 such installations. As a
point of interest, on July 1, 1950, there
were 76 primary sewage treatment plants --
principally imhoff tanks--while today in
North Dakota you will find 37, a decrease
of 39. Lagoons have replaced 50% of the
primary treatment plants in our state. The
same thing is true of secondary plants. In
1950 there were 12 secondary treatment
plants, while today there are 7, with 5 of
these being replaced by lagoons. I960 will
see the replacement of another secondary
plant, which has been used only ten years,
by a lagoon.
Lagoons have encouraged the develop-
ment of a large number of new sewage col-
lection systems in our state. In 1950, there
were a total of 107 sewage collection sys-
tems in North Dakota. In I960, there are
173 sewage systems, 65% using lagoons.
All 66 of the new systems were developed
with this type of treatment. Lagoons have
not only been used by the small communi-
ties in North Dakota, but have become the
type of treatment used by our major cities.
Of the twelve major cities in the state, six
are presently using sewage lagoons. These
include Williston, Dickinson, Devils Lake,
Grafton, Jamestown, and Wahpeton. These
communities range in population from 5 to
12 thousand. Of the other six major com-
munities, Minot (30, 277), Grand Forks
(34, 256), and Valley City (7, 758) will start
lagoon construction sometime during the
present calendar year. Lagoons are being
planned for the cities of Mandan and Bis-
marck. This leaves one major community,
Fargo, which is presently expanding their
secondary treatment plant. We except in
the very near future to find eleven of the
twelve major communities in North Dakota
using lagoons as a treatment method.
The basic design of lagoons now being
built in North Dakota is about the same as
that used for the installation built at Mad-
dock in 1949. Design loading is generally
20 pounds of B.O.D. per acre per day with
a maximum limit of 40 pounds B.O.D. per
acre per day. Due to wide variations in
rainfall and climatic conditions across our
state, there is some difference in design
between the eastern and western portions.
In the western part of our state, rainfall is
less and the soil is generally lighter.
Therefore, to secure proper hydraulic
loading, the B.O.D. loading will often be
in the neighborhood of thirty to thirty-five
pounds per acre per day. We are actively
encouraging the development of two units,
which can be operated in either parallel or
series.
We are still recommending location of
units as far away from existing and future
residential and commercial developments
as is reasonable and feasible. This dis-
tance will vary with local conditions. La-
goons should be located adjacent to a water
course. Recommended dikes are con-
structed much the same as ten years ago
with an 8 foot height, 3 feet of free board,
well compacted, and a width of 8 to 10 feet.
Dike structures vary in width and slope
with the size of the installation. North Da-
kota still recommends a 5 foot liquid depth
with a control structure for lagoon opera-
tion at any selected depth. The lagoon bot-
tom should be made as level as possible.
Influent lines are placed near the center of
the lagoon or in large installations far
enough from any bank to insure circulation.
Interconnecting piping or structures vary
widely but all should offer flexible depth
control. Do not build in complicated fea-
tures -- stick to design features.
'Executive Officer, State Department of Health.
109
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One of the major advantages of lagoons in
North Dakota is the fact that they can be so
designed as to discharge effluents during
periods when the re is sufficient stream flow
to provide dilution water. Most North Da-
kota streams are intermittent with high flows
in early spring, low summer flows, and
often zero flows during the winter months.
Our lagoons are designed to provide winter
storage of about 120 days. Winter is a cri-
tical period for streams in our state and if
all sewage can be held within the lagoon,
real water pollution abatement is being
achieved. We are encouraging operational
practices, which include partial draining
of the lagoon prior to winter freeze-up to
make room for winter sewage flows. The
effluent in the fall months is highly stabil-
ized and adds a minimum of waste load to
the water course. We also encourage a
discharge from the lagoon during the early
spring months when there is adequate di-
lution water in the receiving stream. If the
level of the lagoon can be lowered during
the spring break-up period, the transition
period is more rapid.
Lagoons in North Dakota operate, gener-
ally, with no problems during the summer,
fall, and winter months. There is a spring
transition period when odors may develop
for a period, depending upon several fac-
tors. The length of this transition period
is dependent upon depth of sewage in the
stabilization lagoon, the organic load, the
period of time between freezing and above -
freezing temperatures, the amount of sun-
shine, the type of industrial wastes that the
lagoon receives, the quality of the munici-
pal water supply and perhaps some unknown
factors. The duration of the transition
period in a lagoon may vary from a few
days to an extended period. During the past
ten years we have observed that lagoons
which have been loaded to design standards
present minor transition problems.
Where there have been transition prob-
lems, we have felt that these problems
would have existed during most of the year
were this particular waste being treated in
a conventional type of sewage treatment
plant with the average type of operation
which is found in our state. Also, I might
point out that a lagoon is always subjected
to an FBI type of investigation in regards
to odor, while those visiting conventional
plants know that there will be odor before
they reach the plant; therefore, they do not
make nearly as intense observations of
these odor problems.
We are having some excellent results with
the treatment of industrial wastes in stabili-
zation lagoons and also some problems. A
majority of our lagoons treat domestic
sewage combined with a small industrial
load. One of our earliest problem lagoons
developed severe odors during an extended
transition period due to the fact that large
quantities of milk waste, buttermilk, and
slaughter plant wastes were being dis-
charged to the lagoon. The strength of these
wastes was about four times that of the
domestic sewage received by this treat-
ment device. With eliminationof the butter-
milk and some in-plant separations of
slaughter plant wastes and decrease waste
loads, this problem has been considerably
alleviated, so that the transition period on
this installation is now very short. One of
our outstanding industrial installations is
located at Mandan, North Dakota, at the
Standard Oil Refinery. This nine-acre la-
goon services a 50, 000 barrel a day refin-
ery. The wastes are first treated in an API
separator and then discharged to the la-
goon. The Standard Oil Company has taken
a real interest in the operation of this la-
goon and has carried on a considerable
amount of experimental work. Water tem-
peratures are controlled, aeration is pro-
vided through the use of Kesserling Brushes,
and a floating skimmer removes any oil
separated in the lagoon before it is dis-
charged to the stream. This lagoonprovides
the refinery with considerable oil and
phenol removal and permits the refinery
to discharge the well-treated effluent which
creates no problem in a stream with an
average summer and winter flow of about
6 CFS.
During the last two years, we have had
a rapidly growing potato products proces-
sing industry developing in North Dakota.
This includes a potato starch plant and
several potato flake plants. The wastes
from these potato processing plants have
varied from 860 to 3, 000 mg per liter, 5
day B.O.D. Suspended solids have varied
from 1, 400 mg per liter to 4, 000 mg per
liter. The flake plants have developed a
waste strength which amounts to about 350
population equivalents per ton of potatoes
processed, with these plants varying in
size from about 50 to 100 tons per day. In
all cases where these plants have discharged
110
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their effluent to a lagoon, the major portion
of the waste strength of the lagoon came
from the potato processing plant. Our de-
partment has required preliminary treat-
ment of these wastes before discharge to
a lagoon and found that by two hours'
settling, about 50% of the waste strength
can be removed. These rapidly developing
industries have loaded some lagoons as high
as 150 pounds of B.O.D. per acre per day
during the last year. Operation has been
satisfactory during the summer, fall, and
winter months. However, very serious
odor problems did develop this last spring
and persisted for several months. Grafton,
North Dakota, a community of a little over
5, 000, has a potato flake plant processing
72 tons of potatoes a day and a potato starch
plant processing about 360 tons per day.
The loading on this lagoon was in the neigh-
borhood of 150 pounds of B.O.D. per acre
per day. During the past two months of
open weather with considerable sunshine,
we have found a decrease in the B.O.D.
strength of the lagoon contents, a film of
algae developing, and the treatment proc-
ess taking place. We trust that if proper
pre-treatment of waste is accomplished
that a properly loaded and designed lagoon
will treat these potato effluents.
We also find the transition period is ex-
tended considerably if the lagoon is served
by a municipal water supply which contains
a large amount of sulfates. At the city of
Devils Lake, which has a 95 acre lagoon,
the municipal water supply has 1, 100 parts
per million sulfate. A mild odor was re-
ported at this installation in the latter part
of June this year. This community is soon
changing their water supply, and therefore
will eliminate this problem, but certainly
the amount of sulfates in the municipal
water supply should be considered in the
development of a stabilization lagoon. I
should not intimate that overloading is the
only problem. Both organic and hydraulic
underloading can also produce undesirable
operations. If soil conditions are not ade-
quate or lagoon area is too large, proper
liquid depths will not be maintained and
poor operation conditions will develop.
May I sum up this report from North
Dakota in saying that after ten years of ex-
perience and 113 stabilization lagoons, we
are sure that this is now the accepted
method of sewage treatment in our state.
There have been problems, and there will
continue to be some problems -- mostly
related to the overloading or underloading
of the installation, thereby developing odor
problems during the spring transition
period. If a lagoon is properly designed
and properly operated, it will provide a
community with a trouble-free, economical,
and satisfactory treatment installation.
Ill
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RAW SEWAGE LAGOONS IN MONTANA
by C. W. Brinck *
Raw sewage lagoons have revolutionized
sewage treatment in Montana, In 1952,
upon the urging of the U. S. Public Health
Service, Missouri Basin Office and the kind
invitation of the State of North Dakota,
Montana was included with other Missouri
Basin States in a trip to study lagoon in-
stallations throughout North Dakota. As a
result of this beginning, Montana had 44
standard sewage lagoons in operation and
11 under construction, as of July 1, I960.
We also have a lagoon that was built in
1911, but not recognized as a lagoon. This
lagoon provides sewage treatment for a
community of 2, 730 people and consists of
four ponds, three of which are in operation
and a fourth one which is drying and await-
ing being cleaned. The ponds are operated
in series. Each year, the pond which has
received the primary sewage is taken out
of service after being in use for a full year
and the sludge is permitted to dry and is
bull-dozed from the pond. The following
year, this pond becomes the third in series,
the third pond becomes the second pond in
the series and the second pond becomes the
first in the series. This facility has per-
formed satisfactorily without odors for
forty-nine years. The sewage is very weak
because of large quantities of infiltration
water. This weak sewage was long believed
by State Board of Health representatives to
be the reason for no odors being created at
this sewage pond.
Lagoons have been very successful in
Montana since the first one designed as a
sewage lagoon was constructed and placed
in operation in 1953. Typical comments
concerning sewage lagoons are along this
line: "Most logical and economical way to
meet our sewage disposal problem. "
"Everything about it is excellent and main-
tenance problems are practically zero. "
"We recommend it for any town or city. "
"No upkeep or maintenance problems since
construction other than riprapping banks."
"Very well pleased with operation and
costs - No operational problems so far. "
"Very cheap. " "It is very satisfactory. "
These few comments represent the feel-
ing of many of our communities in the State
that have sewage lagoons. There are still
some communities that do not have lagoons
and look upon the sewage lagoon with some
skepticism. The costs shown in the ac-
companying table reflect land and lagoon
costs only. These costs vary with the cost
of the land. Also, the contractors costs
vary for dirt moving, the type of soil and
the way the earth must be moved to provide
a relatively level bottom for the pond.
Seventeen of the 44 lagoons in Montana
are of the two-cell type. Recommendations
are for two-cell structures because of the
greater flexibility that is provided when the
two lagoons are so designed that they can
be operated either in parallel or in series,
depending upon the load. We particularly
recommend the two-cell lagoon for a com-
munity that is just being sewered for the
first time since it frequently requires con-
siderable time to get all of the dwellings in
the community to connect to the sewer.
This is particularly true these days because
the communities that had sewers a number
of years ago usually were the communities
where a septic tank would not operate sat-
isfactorily due to the tight soil and those
that have remained unsewered have been
able to make septic tanks and cesspools
operate because of the fairly coarse gravelly
soil.
Many of the lagoons in Montana are pro-
vided with a sewage line which discharges
above the water surface. In only one in-
stance has it been reported that the pilings
were raised by ice in the winter. Many
Montana lagoons will have as much as two
feet of ice a short distance away from the
point where the liquid enters the lagoon.
This point is open because of the heat in the
sewage. Many persons have expressed
concern because of the conditions developed
by the cold weather. Some of our lagoons
are located in areas where the thermom-
eter •will drop to a temperature of minus
50 degrees F. , almost every winter. Yet
•Director, Division of Environmental Sanitation, Montana State Board of Health
112
-------
the lagoons operate satisfactorily. Because
of ice conditions, Montana feels that it is
absolutely necessary to design a lagoon to
provide a five feet liquid depth. This may
be reduced to three feet in the summer,
but with two feet of ice to contend with in
some localities, it is necessary to have
some place for the liquid under the ice.
Therefore, practically all lagoons that are
going in are five feet deep.
One lagoon in Montana was established to
handle the wastes from a 23, 000 barrelper
day oil refinery. This oil refinery produces
a waste which contains large quantities of
phenol. The refinery instituted a program
whereby as much water as possible was
conserved and reused, discharging only
that water which had a relatively high dis-
solved solids concentration. After passing
through the oil separator, the waste water
contains both oil and phenols, together with
boiler blow-down wastes, it is discharged
to a two-cell lagoon, operating in series.
In this lagoon, biological activity reduces
the phenol content to a point from approxi-
mately 100 pounds per day to less than 0. 1
pounds per day. Needless to say, manage-
ment, the down-stream users, and the
State Board of Health are pleased with
these results.
Two packing plants use lagoons for their
waste disposal. The tendency here is for
the plants to overload the lagoons, to per-
mit too much blood and other material to
escape in the waste water, thus overloading
the lagoons and creating an odor condition.
In one plant this is quite serious since
there are neighbors nearby and there is no
place for them to discharge their wastes.
The plant was built in an area -where there
were no persons residing a few years ago.
The area has now been subdivided and is
heavily built up.
Lagoons have been considered for sewage
treatment for some of the larger communi-
ties (up to 55, 000 population) but, due to
the excessive pumping costs or the exces-
sive cost for available land, the general
decision has been to use the mechanical
type of treatment for these communites.
We would not hesitate to approve the use of
a sewage lagoon for these larger communi-
ties if the engineers decided that it was the
answer to the problem in Montana.
Lagoons are inexpensive to construct, as
compared with a mechanical plant; for
operation, costs are practically nil as com-
pared with a mechanical plant, and the de-
gree of treatment is much higher than is
ordinarily obtained with the customary
mechanical primary or secondary plant.
Therefore, on this basis, we have nothesi-
tated to recommend sewage lagoons to our
municipalities in Montana. We now find
that many municipalities are convincing
other municipalities on the suitability of
this method of sewage treatment. That, to-
gether with the material that appears in the
literature information from consulting en-
gineers, the State Board of Health, and in
the Readers Digest has been most helpful
in changing a situation in Montana from one
where, about eight years ago, we hadabout
20 acceptable sewage treatment plants in
Montana, and today, we have 85 that are
acceptable and have 9 communities with
money that are proceeding with planning for
construction. These are both mechanical
and lagoons. We hope that within the next
year we will have the sewage from the re-
maining 33 municipalities treated. Twenty-
four have plants needing some improvement,
3 are of uncertain status, but the remaining
6 are making plans and several have al-
ready purchased land for lagoons. Montana,
we hope, will within the next year, be in a
state that will have no raw sewage being
discharged into its streams.
113
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TABLE 32
RA« SEWAGE LAGOONS IN MONTANA
DIVISION OF ENVIRONMENTAL SANITATION
MONTANA STATE BOARD OF HEALTH
Municipality
1950 Census
Population
Ho. Sewer
Connections
Year
Placed in
Operation
Lift
Station
Cost
Number
Lagoons
Total Lagoon
Surface Area
Acres
Acre
Land
Pur-
chased
Land
Cost
Con-
struc-
tion
Cost
Cost/Capita
for Lagoon
Distance between
Lagoon & Bldgr, .
Odors
Baker
Big Sandy
Big Timber
Boulder (State)
Br-.dy
Brockton
Busby
Charlo
Chester
Choteau
Circle
Conrad
Culbertson
Cut Bank
Dent on
Dillon
Dodson
East Helena
Fairfield
Forsyth
Geraldine
Harlowton
Hingham
Hobson
Jordan
Lame Deer
Lodge Grass
Malta
Melstone
Opheim
Plenty, ood
Plevna
Riehey
Roundup
Rudyard
St . Ignatius
Sheridan
Stevens vllle
Towns end
Valier
West Glendive
White Sulphur
Springs
Wolf Point
Worden
1,772
743
1,6,9
900
240
350
200
310
733
1,618
856
1,865
779
3,721
435
3,268
330
1,216
693
1,906
374
1,733
214
205
677
350
536
2,095
195
383
1,862
247
595
2,856
550
781
572
772
1,316
710
1,000
1,025
2,551
225
125
40
23
400
289
169
450
288
145
600
63
80
30
140
735
110
750
59
133
70
250
110
1956 2
1955 1
1959 1
1959 2
1955 1
1955 1
1957 2
1954 1
1954 1
1955 1
1955 8,510 2
1957 2
1958 12,400 2
1959 22,000 2
1955 1
1955 1
1958 8,700 1
1955 2
1955 1
1959 2
1955 1
1959 1
1956 1
1958 2
1954 1
1957 2
1957 1
1958 17,525 2
1957 1
1955 1
1953 2
1959 2
1957 2
1958 7,575 1
2
1956 1
1960 1
1960 1
1959 1
1960 1
1958 7,800 1
1959 2
1959 35,000 1
1956 1
14
9
18
12
3
2
3
3
9
30
15
20
15
43
5
40
5
14
10
8
5
21
3
1
4
2
2
19
2.5
6
30
2
6
26
2
5
6
10
17
11
10
19
48
4
1,200
90 22,500
400
5 250
80 4,000
3,000
40 1,600
185 42,160
11.5 1,805
80 11,500
6 1,000
25 1,815
150/Ae.
350
2,000
47 7,700
80 7,737
18 1,400
800/Ac .
10.6 1,600
16 1,500
20 3,000
13 2,200
20 6,000
40 800
90 3,150
1,200
13,306
22,957
59,290
5,000
6,400
24,457
13,980
14,452
74,405
8,140
23,775
6,883
62,650
29,647
11,000
7,700
25,970
7,895
9,000
34,260
20,488
24,680
7,375
15,952
18,925
19,000
23,740
14,827
18,103
28,255
14,420
37,492
20,382
3,200
19
2''
66
22
19
It
16
19
20
19
7
21
52
43
6
21
15
39
46
16
53
13
30
27
6
29
42
19
14
40
14
37
8
20
1/4 mile
3/4 Mile Yes
1,370 Ft. Yes
2,000 Ft. No
1,200 Ft. No
Yes
2,500 Ft. Yes
Yes
1/2 Mile No
1,200 Ft. No
2,500 Ft. No
2 Miles No
Ho
1/2 Mile No
1/4 Mile Yes
700 Ft. No
Yes
1,000 Ft. No
200 Ft. Yes
1,000 Ft. Yes
1,200 Ft. No
1/2 Mile Yes
150 Ft. No
2,500 Ft. Yes
2,000 Ft. No
1,500 Ft. No
1/4 Mile Yes
-------
TABLE 32
HAW SEWAGE LAGOONS IN MONTANA
DIVISION OF ENVIRONMENTAL SANITATION
MONTANA STATE BOARD OF HEALTH
Municipality
Season when
odors noted
Recurrent
Odors
Odor
Intensity
Time odors
Noted
Description
of odors
Cora-
plaints
Cold Weather
Problem
Overflow
Effluent
used
Days
Maintenance
per year
Sulfates
mg/1
Baker
Big Sandy
Big Timber
Boulder (State)
Brady
Brockton
Busby
Charlo
Chester
Choteau
Circle
Conrad
Culbertson
Cut Bank
Dent on
Dillon
Dodson
East Helena
Fairfield
Forsyth
Geraldme
Harlowton
Hingham
Hobs on
Jordan
Lame Deer
Lodge Grass
Malta
Me1 stone
Opheim
Plentywood
Plevna
Richey
Roundup
Rudyard
St. Ignatius
Sheridan
Stevensville
Towns end
Valier
West Glendive
White Sulphur
Springs
Wolf Point
Worden
Spring Mild Few days sewage No No Yes No None
Spring Yes Strong 14 days Sewage Yes No Yes Irrigation 10 days
No No Yes No 1 day
No No No No 4 days
Spring 10-14 days H2S Few
Spring Yes Slight 1- 2 days Stagnant No No No 2-5 days
Spring 10-14 days Sewage Fe*
None None None 1/2 Hr/day
No No No 20 days
No No Yes Irrigation None
No No Yes No 30 days
No No Yes No 3 days
No No No No Very Little
Spring Yes Light 14-21 days No Yes No No
No No Yes No
Sewage
No No 10 days
Fall No Mild Evenings One No Yes No 5 days
Early Spring 1st year Strong 14 days Sewage Yes Yes Not Yet 5 days
None 1st Year No Practically None
Spring Yes Not too bad 14 days Not serious Few No Yes No 20 days
No No No No 5 days
Spring Yes Mild 10-14 days One pi^F^eae" N° H° 2 dayS
No Very Little Mo 1 day
No Ice raises yes No 2 days
Di^char^e Pipe '
Spring Yes Strong 2 weeks Sulfur Gas No None No VPTV FPW
1000
30-1300
27
35
555
1267
3
600-900
50
805-1050
32
185
53
49
6
267
19
22
200
162
255-530
4
770
500
380
834
886
189
0-914
382
7
7
23
7
65
250
8
300
i *•«
115
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SEWAGE STABILIZATION PONDS IN MINNESOTA
Harvey G. Rogers*
Sewage stabilization ponds have been
used for the treatment of raw sewage and
industrial waste from municipalities in
Minnesota since 1955. As of May, I960,
there are twenty-one municipal projects
for treatment of raw sewage and industrial
wastes which have been completed or are
under construction. These ponds are not to
be confused with the lagoons used for the
disposal of industrial wastes in the state
for many years. These industrial waste
ponds or lagoons have served as a place
for storage of processing wastes from
vegetable canneries, beet sugar plants,
etc. , until the period of the year when the
stream flows are high and wastes can be
discharged safely at a controlled rate into
the stream.
The total water surface area of the
twenty-one pond projects is about 1, 300
acres, or an average of about 62 acres per
installation. Plans for other projects, but
not yet under construction, will have a total
water area of about 300 acres. The sizes
of the ponds range from about 5 acres to
335 acres. The area of each installation
also includes allowance for wastes from
industries in the municipality which, in
some cases, is several times the waste
from only the domestic sources.
Stabilization ponds have not been used for
treatment of raw sewage from small in-
stallations such as schools, resorts, sub-
divisions, etc., although effluent stabiliza-
tion ponds following secondary treatment
have been used where a stable effluent has
been required.
A general practice is to locate the ponds
at least one-half mile from a municipality
and at least one-fourth mile from the near-
est dwelling, although several installations
are located at distances slightly less than
this. All ponds have been designed to pro-
vide for an overflow or discharge into a
lake, stream or drainage ditch.
In all installations at least two ponds,
designed to operate in series, have been
provided. The primary pond is sized ac-
cording to a design five-day BOD loading of
fifteen to twenty pounds per acre of water
surface. A secondary pond is usually one-
fourth to one-half the size of the primary
pond. In cases where the area of the pri-
mary pond is large, (more than sixty acres)
it is recommended that the area be divided
into two primary cells designed to operate
in series or parallel with each other and
in series with the secondary pond. The
dikes are from six to eight feet in height
above the pond bottom to provide at least
three feet of freeboard at maximum liquid
level. Provision is made for six months
storage of designed winter sewage flows by
lowering the level of the ponds during the
fall. A minimum depth of one foot of liquid
is normally retained in the primary pond.
This volume is not considered available as
storage capacity. The dikes and bottom of
the ponds are constructed of relatively im-
pervious soil or sealed to prevent excess
percolation of liquid into the soil. The
dikes are constructed with an inner slope of
at least four to one and an outer slope of
at least three to one.
In only four cases out of the twenty-six
designs, has it been feasible to use grav-
ity flow to the primary pond. Others re-
quire a pumping station and force main.
Construction costs vary widely depending
upon their location, soil characteristics,
topography, etc. Availability of a satisfac-
tory site at reasonable cost has frequently
been a controlling factor in the feasibility
of using ponds . Of sixteen projects for which
construction cost figures are available at
this time, the average cost of the ponds,
including earth moving, overflow struc-
tures, fencing, sealing, seeding and ac-
cess road, was about $940 per acre of
$9.40 per design unit of population equiva-
lent, with a range of costs from about $600
"Chief, Section of Water Pollution Control, Division of Environmental Sanitation, Minnesota State Department of Health, Min-
neapolis, Minnesota.
116
-------
to $4300 per acre. The total costs of these
projects including interceptor and outfall
sewers, pumping stations, land and ease-
ments, engineering, fiscal, legal, etc.,
came to an average of about $3400 per acre
or $34 per design population equivalent.
Land costs also vary widely and will range
up to $500 per acre with an average of
about $200 per acre.
Operation experience has been generally
satisfactory, although some problems have
been experienced with erosion of the dike
at the water line, seepage of liquid through
the dikes, and excessive growth of emer-
gent aquatic weeds. Odors have not been a
problem except for a few days following the
break-up of ice in the spring. This gen-
erally occurs in the first two weeks in
April. Permanent ice cover will begin to
form on the ponds during the early part of
November, and ice and snow cover is vir-
tually complete until the spring break-up.
Ice thickness of up to eighteen inches has
been observed on primary ponds.
Excess loss of liquid due to percolation
has not been a problem after the initial
filling of the ponds. Also loss by evapora-
tion is not a problem since, on the aver-
age, evaporation ranges from ten inches
more to ten inches less than precipitation
during the period of a year.
117
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WASTE STABILIZATION PONDS IN SOUTH DAKOTA
By
Charles E. Carl and Don C. Kalda*
INTRODUCTION
The terminology applied to the treat-
ment devices under consideration varies
with individuals and different areas of the
country. The broad term of waste stabili-
zation pond has received rather general ac-
ceptance in South Dakota as being most
accurately descriptive of the physical and
functional mechanisms of such installa-
tions. A more specific term often applied
to municipal installations is sewage stabil-
ization pond. The term stabilization pond
is considered to be synonymous with oxi-
dation pond and stabilization lagoon when
defined as "those ponds of regular and
controlled shape, depth, and marginal
area, specifically designed and constructed
as a waste treatment device".
The first stabilization pond installation
serving a South Dakota community was
placed into operation at Lemmon in 1951.
Prior to that time, the State of North Da-
kota had several satisfactorily operating
installations. The success of these early
installations attracted much attention in the
neighboring states, and their use spread
rapidly throughout the midwest area. This
method of waste treatment is becoming in-
creasingly popular in South Dakota, and
there are now seventy-seven installations
treating domestic and organic industrial
wastes. Acceptance of this method of waste
treatment is demonstrated by the fact that
no conventional treatment plants have been
built in any municipality in South Dakota
under 5, 000 population during the last five
years.
Rapid acceptance of stabilization ponds
in South Dakota can be attributed to a num-
ber of important advantages of this treat-
ment method over the conventional proc-
esses. A majority of our municipalities
have a population of less than 2, 500, which
size range is particularly adaptable, from
an economic and operational standpoint, to
the use of stabilization ponds. Significantly
reduced costs for sewage treatment has
made it possible to finance construction of
collection systems in practically all of the
smaller municipalities in South Dakota. In
addition to reduced costs of construction,
operation and maintenance of the treatment
facilities, a major advantage of particular
importance to pollution control agencies is
that the degree of treatment remains at a
high level even if the pond is neglected
from an operational standpoint. Widespread
use of stabilization ponds has unquestion-
ably been a significant factor in accelerat-
ing the water pollution abatement program
in South Dakota.
Many areas of investigation and develop-
ment remain to be studied to derive the
full advantages of the pond method of waste
treatment. Such deficiencies in available
data and experience are certainly recog-
nized in our area as new and unexplained
conditions develop.
APPLICATION IN SOUTH DAKOTA
All of the stabilization ponds in South
Dakota have been installed as permanent
waste treatment facilities, and a majority
serve as a complete treatment unit. Stabil-
ization pond installations have demon-
strated an ability to effectively treat raw
sewage under proper loading conditions
with no adverse effects. The treatment
provided by an installation meeting recom-
mended standards of design is considered
to be equivalent to, or better than, that of
most conventional secondary treatment
plants.
The demonstrated capacity of stabiliza-
tion ponds to treat raw sewage has resulted
in construction of an increased number of
'Director, and Assistant Director, Division of Sanitary Engineering, South Dakota Department of Health, Pierre,
South Dakota
118
-------
such installations in South Dakota. With
few exceptions, it is more economical for
the smaller municipality to provide addi-
tional pond area rather than primary treat-
ment. Many Imhoff tanks have been by-
passed when a stabilization pond was con-
structed in order to eliminate the odors
generally associated with such units and
also to decrease operational requirements.
The ability of stabilization ponds to effec-
tively treat raw sewage has been the signif-
icant factor in reducing costs of the small-
er installations far below that of conven-
tional plants providing a comparable de-
gree of treatment.
Stabilization ponds are operating in all
sections of South Dakota ranging from the
sparsely populated western area to the
more densely populated agricultural east-
ern area. The use of stabilization ponds in
South Dakota is not considered limited to
sparsely populated areas where low value
land is available. For the smaller installa-
tions, the aggregate cost of construction
and operation of stabilization ponds in high
value land areas has generally been found
to be significantly less than that of conven-
tional treatment methods. The final choice
of treatment method should necessarily be
reached by a thorough study of local condi-
tions and economic considerations.
A total of seventy-seven stabilization
ponds having a design population of 88,413
persons are presently in operation in South
Dakota. The water surface area repre-
sented by these installations is 801 acres.
Of the total number of stabilization ponds
in operation, sixty-one serve municipal-
ities, one serves a State institution, ten
serve Federal installations, three serve
private installations, and two treat organic
industrial wastes. Significant dairy plant
wastes are treated in conjunction with
domestic wastes in seven of the municipal
installations.
Dairy wastes are being treated effective-
ly in conjunction •with domestic wastes by
stabilization ponds. Organic loadings have
been maintained at a level comparable to
that recommended for normal municipal
installations. A summary of the basis of
design for these installations is shown in
Table 33.
TABLE 33
BASIS OF DESIGN
DAIRY & MUNICIPAL WASTE STABILIZATION PONDS
City
Castlewood
Freeman
Humboldt
Parkston
Redfield
Scotland
Volga
Design B.O.D. (Pounds/Day)
Domestic
85
150
92
220
450
220
144
Dairy
100
120
112
130
100
4B
360
Total
185
210 (1)
204
350
550
268
390 (2)
Area of Pond
(Acres)
16.0
8.3
12.3
15.5
30.2
13.1
21.0
B.O.D. Loading
( Pounds/Acre )
11
25
17
22
18
20
19
(1) Existing conventional plant removes sixty pounds B.O.D./Day.
(2) Existing conventional plant removes 114 pounds B.O.D./Day.
Design loadings for all these installations
except Castlewood are in the range of
twenty pounds B. O. D. per surface acre
per day. A more conservative design was
used for the Castlewood pond since it was
the first application of a stabilization pond
for treatment of combined domestic and
dairy wastes in South Dakota. Loadings in
the magnitude indicated have resulted in
no serious odor problems except in those
installations where abusive wastes such as
whey and buttermilk have been discharged
to the system. The gross organic load
from such discharges together with a high
119
-------
sulfate concentration in the water supply
created serious odor problems at a number
of the installations. Diligent operation of
the dairy plant and control by municipal
ordinance to prevent such discharges is as
necessary for satisfactory stabilization
pond operation as it is for a conventional
plant.
The discharge of such strong wastes
actually creates a lesser problem with a
stabilization pond than a conventional plant
even though the odor problem may make
the situation appear more serious. Reason-
ably high removals of B. O. D. are accom-
plished by stabilization ponds even under
such adverse conditions and the recovery
period to normal operation is generally
short. Some problems have been experi-
enced with filling and maintaining an ade-
quate liquid level in the stabilization pond;
however, such difficulties have generally
been attributed to unsatisfactory soil con-
ditions.
Meat processing wastes from two plants
are being treated effectively and econom-
ically by stabilization ponds. A loading
of fifty ponds B. O. D. per surface acre
was used as the basis of design for these
installations. A loading of this magnitude
is significantly higher than that recom-
mended for treatment of dairy and munici-
pal wastes. Experience has shown that a
stabilization pond treating only meat proc-
essing plant wastes will operate satisfac-
torily and provide a high degree of treat-
ment at a loading of fifty pounds B. O. D
per surface acre per day. Meat wastes
appear to be characteristically well suited
for treatment by stabilization ponds. The
sulfate concentration of the water supply
has also been found to be an important
consideration in the design of stabilization
ponds particularly -when the higher organic
loadings are to be applied.
Field and laboratory studies of one of
the installations treating -wastes from a
small packing house showed that the stabil-
ization pond was operating at a loading of
ninety-five pounds B. O. D. and 11. 6 pounds
total nitrogen per acre per day without
creating nuisance conditions. At this load-
ing, the B. O. D. reduction under summer
conditions was seventy-two per cent result-
ing in an average effluent B. O. D. of 150
parts per million. Additional pond area
has since been provided for this installa-
tion.
A complete listing of the stabilization
pond installations in South Dakota is pro-
vided in Appendix I.
OPERATIONAL FEATURES
AND PERFORMANCE
The mechanism of waste treatment in
stabilization ponds has been described
many times in the literature. The basic
process depends largely on the interactions
of bacteria and algae. Bacteria convert the
decomposable organic matter to more
stable products and in so doing liberate
nutrient elements necessary for algal
growth. The algae utilize these abundant
nutrient materials and through photosynthe-
sis produce the surplus oxygen required
for aerobic bacterial action.
During the extended periods of ice and
snow cover in the northern areas, the
aerobic processes are replaced by anaero-
bic action. A complete ice cover prevents
the escape of odors associated with the
anaerobic processes. The transitional
period from ice to open water is the most
critical time of the year for release of
odors.
The degree of treatment obtained in sta-
bilization ponds is considered to be equiv-
alent to that obtained from most conven-
tional secondary treatment plants. From
the standpoint of the pollutional load dis-
charged to a watercourse, it is significant
to calculate organic reductions in pounds
rather than in concentration. Losses in
liquid volume through seepage and evap-
oration significantly reduce the organic
load discharged. Studies in North and South
Dakota showed that the average minimum
reduction in B. O. D. concentration was 70
per cent which occurred during ice cover.
Maximum reductions in B. O. D. concen-
tration approached 99 per cent. Reductions
in coliform density were found to be 99
per cent or over more than 50 per cent of
the time and, with few exceptions, were
95 per cent or more at all times.
DESIGN CRITERIA
Minimum design criteria for stabiliza-
tion ponds were first developed in South
Dakota in 1953. On the basis of experience
and additional data on performance, sev-
eral revisions have been made to the orig-
inal standards. A copy of the South Dakota
Department of Health Design Criteria for
Waste Stabilization Ponds is provided in
Appendix II.
120
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The basic consideration in the design of
stabilization ponds is the organic loading
that can be applied to satisfy all conditions.
Such conditions are considered to encom-
pass two main objectives in South Dakota;
that is, (1) to provide an adequate degree
of waste treatment, and (2) to provide such
treatment without creating nuisance condi-
tions.
Experience with the early installations
in our State has indicated that providing
one surface acre per 100 population equiv-
alent (fifteen to twenty pounds B. O. D. )
will satisfy both of the above conditions.
The surface loading is based on a liquid
depth of three to five feet. Such a recom-
mended loading is considerably more con-
servative than that suggested by some of
the other states. Loadings have been held
low not particularly for increasing treat-
ment efficiency but to prevent occurrence
of nuisance conditions. The lack of odors
has become an important factor in the rap-
idly increasing use of stabilization ponds
in South Dakota.
Climatic conditions are necessarily an
important consideration in design in our
area. Ice cover normally exists from De-
cember 1 to March 15. With the loadings
recommended, recovery is rapid following
ice breakup resulting in only brief periods
hen odors might occur. The more heavily
aded ponds require increasingly longer
periods to revert to the aerobic state.
Experience in South Dakota indicates
that the sulfate content of the water supply
should be taken into consideration in deter-
mining the organic loading of stabilization
ponds. A high sulfate content is definitely
conducive to more serious odors, and this
effect would necessarily be more pro-
nounced in the heavily loaded ponds. There
is also some evidence indicating that high
sulfate concentrations have a deleterious
effect on the efficiency of the stabilization
process. Further investigation of this
effect on over-all pond operation is re-
quired to develop design recommendations;
however, observations and experiences to
date indicate that sulfate concentrations in
the range of 500 parts per million do not
cause serious problems. Many of the mu-
nicipalities in South Dakota served by sta-
bilization ponds use water with sulfate con-
centrations in excess of 1000 parts per
million. Operational problems have oc-
curred at sometime in almost all instances
where the sulfate content was at this level.
Such problems were not nexessarily limited
to those installations having loadings high-
er than recommended or those treating in-
dustrial wastes.
The choice between use of a single cell
or multiple cells depends on local condi-
tions, downstream water uses, size of the
installations, and other general considera-
tions. Should it be considered necessary to
provide one or more cells in series with
the primary cell, it is recommended that
the loading of the primary cell not exceed
the recommended value of fifteen to twenty
pounds B. O. D. per surface acre.
Loading based on surface area with con-
trolled depth is considered to be the signif-
icant basis for design. Should it be desir-
able to reduce the size of the primary unit,
smaller cells operating in parallel are rec-
ommended. Multiple cell design has dis-
tinct advantages in many instances. A num-
ber of stabilization ponds have been built
using a two-level bottom. Approximately
half the pond is designed for a liquid depth
of three feet and the remainder for a depth
of.five feet. Such a design has the advan-
tage of alleviating filling problems without
increased expenditures for dividing dikes
and additional appurtenances.
Location of stabilization ponds with re-
spect to habitation and the municipality is
often a subject of discussion. The revised
design criteria presently used in South
Dakota specifies no minimum distance that
a pond should be located away from built-
up areas. A study and evaluation of local
conditions similar to that necessary to lo-
cate a waste treatment plant of any type is
considered to be the most practical ap-
proach. The results of a 1956 court action
in South Dakota regarding the location of a
proposed stabilization pond installation
may be of interest. The nearest contents
of the ponds was proposed to be within ap-
proximately 500 feet of a residence, and
the owner brought suit to prevent construc-
tion of the installation. After hearing testi-
mony for two days, the court ruled against
the property owner. The installation •was
placed into operation in early 1957 and no
further legal action has been initiated.
COSTS
Cost data for a majority of the installa-
tions in South Dakota is provided in Appen-
dix III. The average construction cost
121
-------
based on sixty-two installations with a to-
tal design population of 83,811 and varying
in design population from 200 to 10, 600 is
$11. 00 per capita. The range of such costs
is from a minimum of $3. 27 per capita to
$37. 94 per capita. The construction cost
in terms of water surface averaged"
$1185. 00 per acre with a range from
$634. 00 to $3690. 00 per acre. Land costs
are extremely variable and dependant on
local conditions. The data shows an aver-
age land cost of $2. 58 per capita based on
land purchases by forty-six municipalities
with a total design population of 63, 582
persons. The total approximate average
cost of providing sewage stabilization ponds
in South Dakota is indicated to be $13. 58
per capita.
The equivalent of complete treatment
was therefore provided at approximately
the same or at a lesser cost than that of
conventional primary treatment. When
operation and maintenance costs over an
extended period are also considered, the
savings in cost through use of stabilization
ponds becomes even more pronounced.
OPERATIONAL PROBLEMS
Odor problems have occurred in a num-
ber of the installations in South Dakota. A
serious odor problem developed in one of
the earliest installations in the State serv-
ing the City of Kadoka. The most serious
conditions prevailed during the summer
season when it would be expected that sta-
bilization ponds would perform at peak
efficiency and be capable of assimilating
heavy loads. Studies indicated that the
loading was in the order of twenty pounds
B. O. D. per surface acre per day. Sulfides
continued to be produced through the open
•water seasons indicating that anaerobic
decomposition was taking place. The mu-
nicipal water supply has a sulfate concen-
tration of 1038 parts per million and total
dissolved solids of 1841 parts per million.
Investigations resulted in no specific con-
clusions on the cause of the unsatisfactory
conditions. A second cell was constructed
in early 1956 to provide a loading of ap-
pj-oximately twelve pounds, B. O. D. per
surface acre. The installation has func-
tioned without serious nuisance conditions
since that time although some odor prob-
lems have been reported.
Problems with odors have also been ex-
perienced particularly during the spring
transition period from ice to open water in
a number of other installations. Particular
difficulties have been experienced with
those installations treating dairy wastes in
conjunction with domestic sewage. Investi-
gation of these problems has shown that
abusive wastes such as buttermilk or whey
have been discharged to the system. Ex-
perience has shown that stabilization ponds
can effectively treat dairy wastes under
proper loading conditions. It is also sig-
nificant that the most serious problems
occurred where the municipal water supply
contained sulfates in the order of 1000
parts per million.
No use has been made of nitrate com-
pounds for control of odors. Very limited
use has been made of odor masking com-
pounds. Observations made at one installa-
tion using such a compound indicated that
the material was ineffective at the dosage
being applied.
Control of weeds during the initial filling
period often causes operational problems.
Proper design and construction can alle-
viate this problem to a large extent. Some
success has been demonstrated in con-
trolling aquatic vegetation by applying some
of the newer types of herbicides.
Sealing of the bottom and embankments
is essential when ponds are constructed of
pervious soil. Heavy growths of vegetation
have developed in some installations con-
structed in porous soils resulting in great-
ly increased maintenance requirements.
Limited use has been made of bentonite and
asphaltic sealants in South Dakota. The one
experience with bentonite for sealing the
bottom of a pond constructed in extremely
sandy soil was not satisfactory. An asphal-
tic compound was used to seal one cell of
another installation and the facility has not
been in use for a sufficient period of time
to properly evaluate its effectiveness.
Operational problems have been limited
to a small number of the total installations
in operation. Some odors are experienced
during the transition period from ice to
open water in almost all installations. The
recovery period is necessarily of longer
duration for the more heavily loaded ponds.
Alternate freezing and thawing further ag-
gravates the recovery process. Ponds have
been placed into operation in early winter
with no difficulties experienced. Insect
breeding in properly constructed and main-
122
-------
tained ponds has presented no serious prob-
lems. There was one instance of a high
mosquito population at a pond that develop-
ed a dense cover of vegetation before ac-
quiring an optimum depth of water. Since
an adequate water level has been main-
tained and vegetation brought under control,
the problem no longer exists.
CONCLUSION
Waste stabilization ponds have become
an answer to the rising costs of sewage
treatment for a great percentage of the
municipalities in South Dakota. Further
application of stabilization ponds as a com-
plete treatment device for many organic in-
dustrial wastes will bring about further ad-
vances in water pollution control in our
State. Stabilization ponds have fulfilled a
long recognized need for effective treat-
ment at reasonable cost for the smaller
municipalities and industries.
REFERENCES
1. "Sewage Stabilization Ponds in South
Dakota - 1960. " A bulletin of the
South Dakota State Department of
Health; Pierre, South Dakota.
2. "Sewage Stabilization Ponds in the
Dakotas - 1957. " A Joint Report by
the Public Health Service, North
Dakota Department of Health and
South Dakota Department of Health;
Robert A. Taft Sanitary Engineering
Center, Cincinnati, Ohio.
3. "Waste Stabilisation LagoOris - Design,
Construction, and Operation Prac-
tices Among Missouri Basin States -
1959. " A Committee Report of the
Missouri Basin Engineering Health
Council.
4. "Sewage Stabilization Ponds - 1959."
An unpublished paper by Charles E.
Carl presented to School of Public
Health Seminar; University of Minne-
sota; Minneapolis, Minnesota.
5. "Waste Stabilization Ponds in South
Dakota - 1957. " An unpublished
paper by Don C. Kalda presented at
Texas Water and Sewage Works Short
Course; College Station, Texas.
6. Official Files of the Division of Sani-
tary Engineering; South Dakota De-
partment of Health; Pierre, South
Dakota.
123
-------
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APPENDIX II
SOUTH DAKOTA DEPARTMENT OF HEALTH
DESIGN CRITERIA FOR SEWAGE STABILIZATION PONDS
1960
A. General
1. A preliminary report for proposed
sewage stabilization pond installa-
tions should be submitted for re-
view prior to preparation of final
plans. This report shall include the
shape of the cell(s) (B-4), a de-
scription of soil characteristics as
revealed by test borings (E-3),
size, location, and other such pro-
posed design features.
2. The review of proposed stabiliza-
tion pond installations will be
carried out on an individual basis
with local conditions taken into con-
sideration.
3. All plans and specifications shall
be submitted at least 30 days prior
to date upon which action by the
approving authority is desired.
B. Design
1. Original construction should pro-
vide at least one surface acre per
one-hundred (100) population plus
the industrial waste population
equivalent, if significant. In terms
of B. O. D. , a loading of 20 pounds
per surface acre should not be ex-
ceeded. Due consideration should
be given possible future municipal
expansion and/or additional sources
of wastes when the original land
acquisition is made.
2. The choice between the use of
single cell and multiple cell ponds
will be dictated on the basis of
local conditions and downstream
water use. Where a greater degree
of treatment is necessary or desir-
able, one or more cells in series
may be added to the primary cell;
provided, however, that the pri-
mary cell should have a surface
area equal to that set forth in B-l.
3. Where ponds of one or more cells
follow some type of conventional
treatment device, the requirements
in B-l may be reduced to compen-
sate for the B. O. D. reduction in
the pre-treatment unit(s).
4. The shape of all cells should be
such that a uniform perimeter re-
sults. No islands or peninsulas
•will be permitted.
C. Location
1. Ponds should be located at a prac-
tical distance away from built-up
areas with due respect given to
possible future expansion of the
city.
2. Locating ponds in watersheds re-
ceiving significant amounts of run-
off water is discouraged unless
adequate provisions are made for
storm water to by-pass the ponds.
3. In locating ponds, preference
should be given sites which will
permit an unobstructed wind sweep
across the ponds, especially in the
direction of the local prevailing
winds.
4. Proximity of ponds to water sup-
plies and other facilities subject to
contamination should be critically
evaluated to avoid creation of health
hazards or other undesirable con-
ditions.
D. Embankments and Dikes
1. Compacted embankments of im-
pervious materials should be con-
structed.
2. Minimum embankment top width
should be 8 feet. Lesser top width
will be considered for very small
installations.
127
-------
3. Maximum embankment slopes
should not be steeper than:
a. Inner - 3 horizontal to 1 verti-
cal (preferably 4 or 5 or 1).
b. Outer - 3 horizontal to 1 verti-
cal.
4. Minimum embankment slopes
should not be flatter than:
a. Inner - 6 horizontal to 1 verti-
cal.
b. Outer - not applicable, except
that significant volumes of sur-
face water should not enter the
ponds.
5. Minimum freeboard should be 3
feet plus frost heave.
6. Minimum normal liquid depth
should be 3 feet.
7. Maximum normal liquid depth
should be not more than 5 feet. For
ponds with surface areas of more
than 10 acres, special considera-
tion will be given to maximum liq-
uid depths greater than 5 feet pro-
vided such depths are minimal in
area.
8. Embankments should be seeded,
except below the water line. Aflalfa
should not be included in seed mix-
tures since the long roots of this
plant are apt to impair the water-
holding efficiency of the dikes.
Additional protection for embank-
ments (rip-rap) may be necessary
as soil conditions and pond size
warrant.
E. Pond Bottom
1. The pond bottom should be as level
as possible at all points. Shallow
or feathering fringe areas usually
result in locally unsatisfactory con-
ditions.
2. The bottom should be cleared of
vegetation and debris. Organic
material thus removed should not
be used in embankment construction.
3. Soil formations should be relatively
tight to avoid undue liquid losses
through percolation of seepage.
Soil borings to determine soil char-
acteristics shall be made a part of
preliminary surveys to select pond
sites.
F. Influent Lines
1. Any generally accepted material
for pond piping will be given con-
sideration but the material selected
should be adapted to local condi-
tions. Special consideration should
be given to the character of the
wastes, possibilities of septicity,
exceptionally heavy external load-
ings, abrasion, the necessity of
reducing the number of joints, soft
foundations, and similar problems.
2. The influent line into single-celled
ponds should be essentially center-
discharging. Influent lines into the
primary section of multiple-celled
ponds should be essentially center-
discharging, but this does not apply
to those cells following the primary
cell in series operation.
3. Gravity inlet lines should be de-
signed to discharge horizontally.
Pressure inlet lines may discharge
vertically, however, the end of the
pipe should be located approximate-
ly one foot above the bottom of the
pond and should not extend to an
elevation such that ice will damage
the terminal structure during win-
ter operations.
4. The end of the discharge line should
rest on a suitable concrete apron
with a minimum size of two feet
square. Larger aprons and influ-
ent piping supports are suggested
in cases where the soil is unstable.
Flow splitters or dispersing de-
vices are also desirable where a
horizontal type of influent line ter-
minal structure is utilized.
5. Influent and effluent piping should
be located to minimize short cir-
cuiting within the pond.
128
-------
6. Manholes or clean-outs are recom-
mended where pipes pass through
the embankment.
7. Influent lines should be placed in or
near the bottom. The use of ex-
posed dikes carrying influent lines
to the center of the pond will not be
approved.
G. Interconnecting Piping and Overflows
1. Interconnectingpiping and overflows
should be of suitable material of
ample size. The use of frost proof
overflow manholes or valve boxes
for controlling liquid levels in the
pond is recommended. Multiple in-
fluent lines to such structures
should be provided and arranged so
that overflows will ordinarily come
from, at, or near the surface of
the pond. The lowest of the multiple
influent lines to such manholes or
structures should be at least twelve
inches off the bottom to control
eroding velocities and to avoid pick-
up of bottom deposits. Means for
draining the pond are recommended
particularly for the larger installa-
tions.
2. Overflow lines should discharge on-
to anchored concrete slabs. These
lines should be vented if siphoning
may be developed.
H. Miscellaneous
1. The pond area should be adequately
fenced with a stock-tight fence.
2. Appropriate signs should be pro-
vided to designate the nature of the
facility.
3. Provisions for flow measurement
should be provided. Facilities for
installation of a weir would be ade-
quate for most installations.
I. Industrial Wastes
1. Ponds for industrial waste require
special planning and study, and
these suggested minimum standards
may not apply. The South Dakota
Department of Health should be
consulted on such problems before
the design phase is completed.
129
-------
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LAGOON OPERATING EXPERIENCE IN IOWA
R. J. Schliekelman*
In Iowa, the use of waste stabilization
ponds for treating raw sewage has become
quite popular among the smaller commu-
nities where the provision of conventional
sewage treatment sometimes is a great
financial burden. This mode of treatment
was not definitely encouraged as was done
in the early 50's in the Dakotas. It was felt
that a number of factors were not as favor-
able for Iowa conditions as compared with
the Dakotas which had the greatest exper-
ience with the method. Soil characteristics
sometimes were not as favorable due to the
glacial sand and gravel deposits prevalent
in the northern areas of Iowa. Heavier
farm density has made the selection of
sites with suitable isolation from habitation
more difficult. Finally, higher land costs,
commonly in the $300-$500 per acre range,
serve to decrease somewhat the cost ad-
vantage of the lagoon method of treatment.
One temporary lagoon serving a 60-home
housing development was constructed in
1954, but the first municipal lagoon was
not constructed until 1956. Since that time,
the waste stabilization lagoon has been
growing in popularity and as of June 30,
I960, a total of 36 lagoons were in opera-
tion or under construction. Of this total,
22 lagoons are serving municipalities with
the remainder of 14 serving miscellaneous
installations, such as housing develop-
ments, mobile home parks, camps, and
others. In addition, another 42 lagoon in-
stallations are in the planning stage with
plans approved or preliminary engineering
reports submitted. At the present time,
the 22 municipal installations are only a
small percentage of the 346 municipalities
with sewage treatment.
It is of interest to note that 1 5 of the 22
municipal installations are serving com-
munities with new sanitary sewer systems.
We feel that the public health and other
benefits accruing from a sanitary sewer
system would not have been possible in
many of these communities without the rel-
atively lower cost of the lagoon method of
treatment.
While the experience of Iowa with the la-
goon is not as extensive as the other states
with more installations, a brief summary
of experiences and design and operation
practices may be helpful. However, only
factors which are deemed particularly
significant will be discussed.
Our state has benefitted from the exper-
ience of the other states in the Missouri
River Basin and as a result all of our com-
pleted installations have operated quite suc-
cessfully. The South Dakota Department of
Health Design Criteria for Sewage Stabili-
zation Ponds was first used as a guide for
general design features. Tentative stand-
ards based on a draft of the lagoon section
of the GL-UMR "Standards for Sewage
Works" were drawn up in 1958.
Area Loadings
Surface area is one of the basic consid-
erations in the design of waste stabiliza-
tion lagoons. Population loadings of 100
persons per acre, or 20 Ibs. of BOD per
acre, have been used for design in Iowa.
As in the Dakotas, the critical period for
aerobic conditions occurs during the tran-
sition from ice cover to open -water. To
prevent, or minimize, possible odor com-
plaints, these aerobic conditions must be
established as rapidly as possible. Dakota
experience indicated a minimum recovery
period with the 20 Ibs. of BOD loading,
and this figure has also been adopted by
Iowa.
'Public Health Engineer, Iowa Department of Public Health.
133
-------
Undoubtedly, this loading is conservative
but will be used in the majority of installa-
tions until experience indicates that heavier
loadings will produce satisfactory results
under winter operation or spring ice break-
up conditions. Observations of a limited
number of lagoons during the transition pe-
riod in the spring have indicated little or
no odcjrs or complaints.
Design loadings of school lagoon instal-
lations have been based on the principle of
complete retention of all flows during the
school year with some allowance for seep-
age and evaporation losses. An area re-
quirement of 0. 1 acre per 100 pupils with
a water usage of 10 gallons per capita was
calculated and other water usage figures
are in direct ratio. Available BOD figures
for schools indicate this approach would
give the proper BOD loading.
Overflow Structures
For maximum flexibility in operation,
the overflow structure should provide for
varying the pond operating levels. The
most common structure is a manhole di-
vided by a wall containing stop planks. An
influent line at the Z'-3" depth and a lagoon
drain line leading to this manhole provides
a means of regulating the depth between
maximum depth and complete drainage.
In northern climates, the overflow struc -
ture must be so designed that ice formation
will neither stop the overflow or damage
the structure.
Multiple Cells
Visits to other states indicated consid-
erable difficulty in maintaining a satisfac-
tory liquid depth in single cell installations,
with resultant odors and excessive weed
growths. Benefitting from this experience,
our State has required two cells in most
large installations and that they be capable
of being operated either in series or in
parallel. With ponds designed to operate in
parallel it is possible to divert all flow to
one pond where the community is installing
a new sewer system or the water usage is
low.
For lagoons operated in series the en-
tire organic load will be applied to the pri-
mary unit. However, we have not required
an increase in total area since we visual-
ize series operation for better B. O. D. and
coliform reduction and a lower algal con-
tent in the effluent during summer months
when higher loadings on the primary unit
can be tolerated. On the other hand paral-
lel operation during the winter months
would produce the lightest loading in each
pond and facilitate aerobic recovery dur-
ing the spring transition period.
Soil Permeability
The absence of a method for determin-
ing the expected permeability of the soil in
the bottom and embankments of waste sta-
bilization ponds is becoming more signifi-
cant with the increasing use of this method
of treatment. Fortunately, all of our in-
stallations have been relatively imper-
meable and satisfactory water levels have
been maintained. Soil borings have been
required and planning for sealing with clay
has been facilitated by this means. Pos-
sibly, adequate compaction has been a
factor, since all specifications have called
for sheep-foot rolling.
Construction Costs
Comparison of stabilization lagoon con-
struction costs with conventional treatment
costs show a markedly lower per capita
cost for the lagoons. Cost data, however,
has not been thoroughly analyzed to include
consideration of relative land costs and
operation and maintenance requirements.
Per capita lagoon construction costs
have varied from a low of $7 to $38 with
earth moving costs varying from 1 8Ł to
39Ł per cubic yard. Land costs have ranged
from $250 to over $700 per acre.
Industrial Application
Industrial applications have been rather
limited except for the treatment of domes-
tic sewage from the plants. Creameries
contribute up to about one-third of the BOD
loading of a number of municipal lagoon
installations without adverse effects. Con-
struction is nearing completion on a large
milk plant which will employ a high rate
trickling filter followed by a waste stabil-
ization lagoon. Treatment results will be
followed closely.
134
-------
During a two-year period ending in April In conclusion, we feel that the efficacy
1956, pilot plant studies were carried out of the waste stabilization lagoon has been
by an Iowa meat packing plant on combined demonstrated by wide experience. On the
anaerobic-aerobic treatment. Excellent basis of raw sewage loadings established
results were obtained and the process will in the Dakotas, the required land area may
be discussed by Mr. F. W. Sollo of Swift preclude use of these facilities in some lo-
and company in a paper on Wednesday. Re- calities. Unless heavier loadings can be
ductioninland requirements possible with demonstrated as practical for climates, it
the anaerobic process may stimulate its is expected that the statilization lagoon
development for use with other wastes. will find its greatest use in the smaller
community.
135
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WASTE STABILIZATION PONDS IN KANSAS
by
Russell L. Gulp*
Introduction
In relating the Kansas experience with
waste stabilization ponds, an attempt will
be made to avoid repetition of other mate-
rial presented here, and emphasis will be
placed on conditions and practices which
may differ from those in other areas.
The first waste stabilization pond in Kan-
sas for the treatment of raw municipal
sewage was built at Frankfort in 1956.
Prior to that time oxidation ponds had been
incorporated as a part of sewage treatment
works in 24 Kansas communities, the first
of these being constructed at Mt. Hope in
1937. All of these early oxidation ponds
received treated or partially treated mu-
nicipal wastes, and all of them functioned
very well with little operating attention. At
present there are 53 waste stabilization
ponds in the state which are designed as the
sole method of sewage treatment. They
have had an appeal to the small community
because of their low initial cost where land
is cheap, their ease of operation, and their
low maintenance costs. Waste stabilization
ponds have filled a special need in fringe
areas for temporary treatment works.
They have often been used to serve the ini-
tial development in an area until property
values reached a level which would support
a large sewer district with the necessary
trunk sewers and conventional treatment
facilities.
Uses
Ponds can be utilized to serve a variety
of purposes in the treatment of waste
waters:
1. The principal use of waste stabiliza-
tion ponds is for the complete treat-
ment of sewage within the pond cells.
2. Oxidation ponds may be used for ter-
tiary treatment following trickling
filters and final settling basins. In
Kansas the BOD load on oxidation
ponds used for tertiary treatment is
calculated by use of the N. R. C. for-
mula, but for this purpose the maxi-
mum allowable pretreatment effi-
ciency is taken as 80 percent.
3. Oxidation ponds have been used for
secondary treatment in special situa-
tions, but these are exceptions to the
general practice of following conven-
tional primary facilities with conven-
tional secondary units.
4. Oxidation ponds have been used inlieu
of final settling basins in two in-
stances, but again this is uncommon,
and conventional final tanks apparently
are preferred because they are better
adapted to recirculation and control
of the hydraulic loading applied to
trickling filters.
5. At one conventional sewage treatment
plant a waste stabilization pond is
used to receive storm water over-
flows, thus avoiding the by-pass ing of
untreated storm flows to the receiving
watercourse.
6. During the course of housing develop-
ment in some areas, waste stabiliza-
tion ponds have served dual purposes.
After initial temporary use as the
only means of sewage treatment, la-
goons have subsequently been con-
verted to use as oxidation ponds for
tertiary treatment following a con-
ventional plant.
7. Waste stabilization ponds have been
used to a limited extent for treating
creamery wastes along with about
equal volumes of domestic wastes.
•Chief, Water Supply Section, Division of Sanitation, State Board of Health
136
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8. Oxidation ponds have been widely used
in Kansas as one process in the treat-
ment of oil refinery wastes.
Design Considerations
In designing waste stabilization ponds,
site selection is a critical feature. The
distance to houses should be the same as
for other types of sewage treatment facili-
ties even though the process appears to
have less nuisance potential. The direction
of prevailing winds is another factor in
pond location. Finding sufficient areas of
suitable terrain which are free from flood-
ing has presented a special problem at
some Kansas sites, but for permanent fa-
cilities, this type of site is required. For
temporary ponds some flooding risk can be
taken.
The extreme variability of rainfall and
evaporation in Kansas is a significant fac-
tor in the planning of waste stabilization
ponds. Consideration must be given to the
maintenance of minimum water depths of 2
to 3 feet over an area large enough to per-
mit aerobic treatment of the wastes. Dur-
ing an average year the net water loss
(evaporation minus rainfall) from a water
surface amounts to 5 inches at the eastern
Kansas border and to about 50 inches in the
southwestern corner of the state. Years of
maximum evaporation and minimum rain-
fall often coincide and the net water loss can
be as much as 30 inches in the eastern
Kansas and 82 inches in the southwestern
part of the state. Another critical factor
in maintaining water levels is the necessity
to limit seepage from the ponds to 1/4 inch
per day.
To give some insight into the mainte-
nance of adequate water levels, calcula-
tions have been made of the minimum
quantity of sewage discharge required to
ponds in terms of,gallons per capita per
day. This was done on the basis of an ac-
tual connected load of 160 persons per acre
of pond and seepage of 1/4" per day. In an
average year the total requirements vary
from 45 to 75 gallons per capita per day,
east to west across the state. In the driest
years, sewage flows of 60 to 90 gallons per
capita per day are needed. This means
that single cell ponds can be used only in
the eastern 1/4 of Kansas, and that 2 or 3
cells must be used in other parts of the
state. The importance of controlling seep-
age is emphasized by the fact that 42 1/2
gallons per capital per day of these total
inflow requirements are needed to compen-
sate for the 1/4 inch per day of seepage.
To control seepage, three types of pond
seals have been successfully used: com-
pacted select clays and bentonite and poly-
phosphate admixtures. When bentonites
are used, they are applied to the scarified
bottom of the pond at the rate of 5 to 11
tons per acre, then wetted and compacted.
The usual cost of sealing with bentonite is
about 1.5 to 3.0 cents per square foot.
In Kansas the maximum recommended
loading for permanent waste stabilization
ponds receiving domestic sewage is 27
pounds of 5-day BOD per acre per day. For
interim ponds the upper limit is 51 pounds.
Actual loadings in Kansas vary from 16 to
51 pounds for waste stabilization ponds,
although a few oxidation ponds receive
heavier loadings. The actual loading on the
oxidation pond at Lincoln is 135 pounds.
Nearly 20 years' experience with this pond
indicates that it remains aerobic through-
out the year. Although some states give no
credit for secondary ponds when the ponds
are operated in series, Kansas does. It
has been found that the series arrangement
is beneficial along streams needing high
removal of algae, BOD, or coliforms.
Also multiple cells are advantageous when
the loading is seasonal or light, when evap-
oration or seepage losses are high, or
when a new sewer system is being served.
All waste stabilization ponds in Kansas,
except those considered temporary, are
designed with three cell practice.
Kansas experience has demonstrated the
necessity of soil sterilization to control
weeds -where the -water is less than two
feet deep. An effective sterilant should be
resistant to leaching and toxic to weeds,
but not to algae.
DuPont weed killers sold under the trade
names of "Televar" and "Karmex" have
been used extensively with good results.
In designing outlet structures for ponds,
provision should be made for varying the
water depth, since experience has shown
that reducing the depth to less than two
feet will speed the recovery of an over-
loaded anaerobic pond. In the absence of
such an arrangement, sodium nitrate has
been used successfully to reduce odors
during upsets.
137
-------
Some pond effluents have been observed
to have a fairly high BOD due to the high
algal population, and while there has been
no trouble to date with the oxygen balance
in receiving streams some thought has
been given to the possible use of the Brit-
ish microstrainer for the removal of algae
from pond effluents before discharge to the
watercourse in the event that such diffi-
culty should arise.
Creamery Wastes
Kansas has had limited experience in the
treatment of creamery wastes along with
domestic sewage in stabilization ponds. At
Valley Falls, milk and meat packing
wastes contribute about 50% of the total
load, and the ponds were designed for
18 pounds of 5-day BOD per acre per
day. The light loading was used because
of the industrial tendency to relase slugs
of strong organic wastes and because of
the rapid oxygen usage of the milk wastes
Some odors have been reported from
this installation during spring thaws, but
there have been no serious problems
because of the isolated pond location.
At Erie, a pond is under construction
for treating combined municipal and
creamery wastes, with the creamery
wastes comprising 60 percent of the total
BOD. The loading again is 18 pounds of
5-day BOD per acre per day.
At Council Grove the creamery wastes
amount to about 25 percent of the total BOD
load. The ponds are sized on the basis of
18 pounds for the creamery load plus an
equivalent domestic load, with additional
pond capacity for the remaining domestic
BOD based on 27 pounds of 5-day BOD per
acre per day. This is a new pond and no
operating data are available.
None of these three cities permits the
discharge of whey into the city sewers or
lagoons, and the creameries dispose ofthe
whey separately.
Oil Refinery Wastes
Seven oil refineries in the state have oxi-
dation ponds in use, under construction, or
planned. In all cases small concentrated
waste streams are stripped of sulfides,
ammonia, or phenols before entrance to the
plant sewers in order to limit the concen-
trations of these substances in the main
waste stream to 15 ppm sulfides, 15 ppm
ammonia, and 7 ppm phenols. All of the
refineries provide oil separation as a first
step in pretreatment. Beyond this stage,
the pretreatment processes vary. In four
of the refineries the oil separator effluent
flows directly to oxidation ponds. The first
pond cell is a small one, which is usually
called a skimming pond since additional oil
is removed from the water surface in this
unit. The total detention time in the oxida-
tion ponds is about 120 days, because of
the substantial time required for oxidation
of ammonia and lowering of the BOD in re-
finery wastes.
Three of the refineries employ more ex-
tensive pretreatment in order to reduce the
size of the ponds required. One refinery
plans to use a trickling filter followed by
41 days in oxidation ponds. Another plans
to install about 45 minutes of preaeration,
chemical precipitation, settling, and to
provide 60 days retention in ponds. The
third plans to use 5 days of preaeration and
oxidation ponds with 60 days retention.
The principal advantages of oxidation
ponds over other biological processes for
the treatment of refinery wastes appear to
be: their great capacity to handle shock
loads or slugs, simple maintenance, and
the relative ease with which extra storage
can be built in for retaining the treated
wastes during flows in the receiving stream
which are less than the minimum required
for dilution of the effluent. One refinery
provides sufficient pond area to contain all
wastes without discharge of effluent at any
time.
Maintenance
The need for daily maintenance of la-
goons and oxidation ponds is not as urgent
as for conventional types of treatment, but
planned maintenance at regular intervals
is essential in order to protect the dikes,
keep weeds from growing in the shallow
water, and to avoid the breeding of mos-
quitoes or other pests. Weeds and willows
will grow in shallow water areas unless
controlled by soil sterilization initially,
and then by mowing. Broad leafs and wil-
lows can be controlled by spraying with
herbicides if necessary. Dikes and struc-
tures should be inspected regularly for
138
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erosion from wind and rain or for burrow-
ing by rodents.
Health Considerations
Waste stabilization ponds offer substan-
tial protection to the public health andcom-
pare very favorably with conventional
methods of sewage treatmentin this respect.
They provide prolonged storage of the
wastes, usually for 20 to 90 days, a safe-
guard not commonly found in other types of
sewage treatment. Extensive experience
with storage of raw water in water works
practice demonstrates that 30 to 90 days
storage will reduce coliform organisms by
98 per cent or more. Similar reductions
have been observed on a more limited scale
in the operation of waste stabilization ponds
in Kansas. Pathogenic bacteria are partic-
ularly susceptible to destruction by storage.
Conventional treatment processes ordi-
narily handle the sewage at full strength
except for the limited dilution afforded by
recirculation when practiced. Stabilization
ponds provide immediate dilution of the
wastes; the daily dilution being in the order
of 20:1 to 90:1. The over-all effect of this
great reduction in strength of the waste is
beneficial. It avoids the exposure of full
strength raw sewage to the atmosphere and
reduces the opportunities for contact of
pathogens by insects and rodents. Addi-
tional protection is afforded since settled
sludge is covered by water rather than be-
ing exposed as in sludge drying beds.
Less handling of equipment contaminated
by sewage is necessary for operators of
waste stabilization ponds, thus reducing
their exposure.
Summary
To summarize the Kansas experience
with waste stabilization ponds, they have
been successfully applied to the treatment
of domestic and certain industrial wastes.
They are especially suited to handling the
wastes from small communities. Mainte-
nance is minimal but essential. Waste
stabilization ponds provide as much public
health protection as conventional treatment
methods. No more nuisance, and perhaps
less, occurs with this type of treatment
than with convention methods. The cost of
ponds for cities smaller than 3,000 in pop-
ulation is less than the cost of conventional
treatment. However, the difference is not
sufficiently great to preclude the use of
conventional facilities on a cost basis under
many conditions, and both types should be
considered in solving the treatment prob-
lems of small communities.
The design of waste stabilization ponds is
dependent on characteristics of the sewage
flow, rainfall, evaporation, seepage, topog-
raphy, and soil conditions. While the
structural design is not complicated, a
basic understanding of the biological and
chemical processes is essential to a suc-
cessful design.
As more operating experience is gained,
as new knowledge is produced by research,
and as information is exchanged at forums
such as this, it should become possible to
delineate more precisely the design crite-
ria for waste stabilization ponds and to
understand more fully the fundamental
processes involved.
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WASTE STABILIZATION LAGOONS IN MISSOURI
by
Jack K. Smith*
Probably the first sewage lagoon in Mis-
souri was constructed at Potosi about 18 or
19 years ago. This lagoon was preceded by
a septic tank. The septic tank was not prop-
erly maintained and removed only a portion
of the objectionable material in the city
sewage.
The lagoon which was constructed about
1500 feet below the septic tank served to
reduce the pollutional load to the stream.
By modern standards the lagoon was not
properly constructed, but it did reduce the
organic load of the partially treated sew-
age. Mr. A. R. Baron, Division of Health
District Public Health Engineer, noted the
effectiveness of the treatment works and
suggested that properly designed and con-
structed lagoons might afford adequate
treatment.
In 1952, a large open septic tank 65 feet
wide by 150 feet long and 5 feet deep was
placed in operation at Ruskin Heights, Jack-
son County, to serve as a temporary sew-
age treatment device until a modern trick-
ling-filter type plant could be completed.
The open septic tank operated as a lagoon,
producing a stable effluent without objec-
tionable odors.
At Warsaw, a natural lagoon was created
when the water level in the Lake of the Ozarks
dropped. The original lagoon was very shal-
low, less than two feet deep. However,
homes in the immediate vicinity reported
no odors.
For the period of 1953 to June 30, I960,
247 lagoons serving municipalities, re-
sorts, motels, schools, subdivisions,
slaughter houses, poultry processing plants,
milk plants and automatic laundries have
been constructed and placed in operation in
Missouri. There are numerous other in-
stallations throughout the state including
those at private residences that we do not
have data on. The 247 lagoons presently in
operation are designed totreat wastes from
301,228 persons.
In 1958 we made a study of the costs of
municipal lagoons and included a land cost
of $300 per acre with a lagoon site requiring
at least 11/2 times the water surface area.
We arrived at a. per capita cost of $9.84.
At the same time we computed the average
per capita cost of mechanical plants and
found that to be $41. 58. The difference in
per capita cost is $31.74. This difference
times the population equivalent served by
the lagoons represents a savings in first
cost of $9, 560, 977. We estimate that the
annual operating cost of lagoons is less
than one tenth the operational cost of me-
chanical plants.
Lagoon sizes vary from the individual
size of 800 square feet water surface area
to municipal installations with a water sur-
face area of 50 acres. The largest waste
stabilization lagoon system is now under
construction at Poplar Bluff, Missouri,
with a design population of 29, 200 and a
total lagoon water surface are of 146 acres.
As of July 1, I960, the municipal lagoon
census in Missouri was as follows:
Cities Using Waste Stabilization 45
Lagoons for Sewage Treatment
Cities Where Waste Stabilization 18
Lagoons Are Under Construction
Cities Where Waste Stabilization 46
Lagoons Are Proposed
Municipal lagoons are designed on the
basis of 34 pounds B.O.D. per acre.
•Executive Secretary, Missouri Water Pollution Board
140
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The various uses for waste stabilization
lagoons in Missouri are as follows:
In the metropolitan areas of Kansas City,
Missouri, St. Louis, Columbia and Mexico,
waste stabilization lagoons have been used
for interim treatment pending completion
of trunk sewers and permanent treatment
works. The design loadings are 400 per-
sons per acre.
Some odor problems have developed in
the winter months. These odor problems
can be adequately handled by the addition
of sodium nitrate applied in the inlet pipe
or around the edges of the lagoon at the
rate of one pound of sodium nitrate per
pound of B.O.D.
Near Wright City, Missouri, the Wright
City Meat Company in 1956 constructed a
waste stabilization lagoon for the treatment
of the wastes arising from slaughtering and
meat processing of hogs and beef. The av-
erage kill of hogs is 8 to 20 per week. The
average kill of beef is 4 to 8 per week. The
slaughter house is served by a private well
that is metered; the average weekly water
pumpage for all purposes is approximately
4, 000 gallons. The lagoon has a water sur-
face area of 100 feet by 250 feet at the 3-foot
depth; to date there has been no overflow.
The water level has been stabilized at ap-
proximately 2 1/2 feet. Based on present
design criteria for slaughtering and proc-
essing establishments of 400 population
equivalent per acre of water surface area,
this lagoon is approximately twice the area
deemed necessary. It should be pointed out
that the Wright City Meat Company does not
save the blood. The lagoon is located within
150 feet of the slaughtering and processing
establishment; there have been no odor prob-
lems or nuisance conditions to our knowl-
edge. The Wright City Meat Company is a
drive-in retail establishment and odors and
nuisance conditions would, of course, be
very detrimental.
Waste stabilization lagoons have been
used for treating the wastes from poultry
processing plants. At Cabool, Missouri, a
waste stabilization lagoon with a water sur-
face area of 7 1/2 acres was placed in op-
eration inNovember, 1958. The design ba-
sis was 34 pounds B.O.D. per acre. In
July of this year the plant was processing
10, 000 chickens per day and the water usage
was 260, 000 gallons over a 12-hour period.
In the des ign of the waste stabilization lagoon
the consulting engineers designated a sew-
age flow of 150,000 gallons per day. The
waste stabilization lagoon is constructed
near the municipal sewage treatment plant.
It was proposed to pump the supernatant
from the digesters to the lagoon; however,
until recently the city was pumping all of
the raw sludge from their treatment plant
to the lagoon. The sewage treatment plant
is designed to serve 1,750 persons.
AtNoel, Missouri, a chicken processing
plant is served by a 20.2-acre waste sta-
bilization lagoon. The design basis is 34
pounds B.O.D. per acre. This lagoon was
placed in operation in January of this year.
It is anticipated that the plant will process
44,000 chickens per an 8-hour day. Pres-
ent production at the plant is in the 30, 000
to 40,000 chickens per eight hours.
At Purdy, Missouri, a waste stabilization
lagoon with a water surface area of 8, 000
square feet at the 3-foot depth was placed
in operation inNovember, 1959. This lagoon
is designed to treat the wastes from an
automatic laundry with ten machines and
one toilet. The anticipated sewage flow is
2, 020 gallons per day. To date this lagoon
has operated quite satisfactorily. A pre-
vious lagoon installation serving a coin-op-
erated laundry at Eldon, Missouri, which
was in operation for a period of about three
years has now been abandoned. This op-
eration was considered satisfactory.
Several public schools constructed
through the reorganizational program for
rural schools have built waste stabilization
lagoons. These lagoons are designed on
the basis of 800 persons per acre. Where
ground garbage is discharged into the sew-
er system the lagoon area is increased
30%. Actual sewage flow data is not avail-
able for these school installations. We have
observed that there is very little, if any,
overflow from these lagoons. During the
last three to four years rainfall has been
near normal and evaporation has not been
excessive. During the summer months when
schools are not in use the water level in
the lagoons is lowered six to eight inches.
Organizational camps such as the Wind-
emere Baptist Assembly, Roach, Missouri,
Camden County, utilizes a waste stabili-
zation lagoon for sewage treatment. The
camp is used only during the summer
141
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months. The lagoon design basis is 200
persons per acre. This installation has
been entirely satisfactory.
Lagoons are in use at Aurora, Missouri,
following primary sedimentation, trickling
filter and sludge filter installations. Two
lagoons are provided, one with a water sur-
face area of 3. 3 acres and the other with a
water surface area of 4.6 acres. Each la-
goon is designed on the basis of 67 pounds
B.O.D. per acre. Actual operating results
are not available but visual inspection re-
veals a satisfactory effluent.
At Monett, Missouri, a 4. 59-acre waste
stabilization lagoon has been constructed
following a standard rate trickling filter
plant with final settling. The design load
on this lagoon is 31 pounds B.O.D. per
acre. Laboratory results are not available
but visual inspection reveals satisfactory
stream conditions.
Waste stabilization lagoons have been
used satisfactorily for treating the wastes
from a creamery at Emma, Missouri.
This creamery constructed three lagoons
with a total water surface area of 2. 95
acres and a water depth of five feet in 1955
to treat milk waste. The following results
have been recorded:
1. Date October 18,
Total Flow, Inlet
B.O.D. -Raw Waste
B.O.D. -Raw Waste
B.O.D. -applied
B.O.D. of effluent
Reduction of B.O.D.
2. July 19, 1956
Total Flow, Inlet
Total Flow, Outlet
B.O.D. -Raw Waste =
B.O.D. -Raw Waste =
B.O.D. -applied =
B.O.D. of effluent =
1955
= 11, 700 gallons
= 1192 ppm
= 116 pounds
= 39.3 pounds
per acre
= 112 ppm.
= 90.5% assuming
outflow
equals
the inflow
= 14, 550 gallons
= 8, 500 gallons
= 2, 700 ppm.
= 327.2 pounds
= 110.9 pounds
per acre
54 ppm. or
3.8
pounds
98.8%
Reduction of B.O.D. =
In the spring of 1956, septic conditions
accompanied by odors developed. At this
time the milk plant was receiving over twice
the average volume of milk and cream. One
hundred pounds of sodium nitrate per day
was added until the lagoons were again
aerobic, a period of about one week. Since
that time 400-500 pounds of sodium nitrate
per week have been added.
Recently, the Adams Dairy near Blue
Springs, Missouri, constructed two waste
stabilization lagoons, one with a water
surface area of 5.25 acres and the other
with a water surface area of 5.28 acres;
the total water surface area being 10. 53
acres. The design basis for the lagoon was
45 pounds B.O.D. per acre. A composite
sample of the raw wastes collected on
April 27, I960, showed that the B. O. D.
was 1130 ppm. , and the total sewage flow
was 60, 000 gallons for the 24-hour period.
The total pounds of B. O. D. to the lagoon
amounted to 568 or 53. 7 pounds of B. O. D.
per acre. The lagoon was placed in opera-
tion in March, I960. The operation of this
installation is considered to be satisfac-
tory.
One of the first municipal lagoons in
Missouri was in Montgomery City. Several
surveys have been made of this lagoon and
the following information obtained:
Dissolved oxygen in the Montgomery City
lagoon varies from 4 to 17. 6 ppm. B.O.D.
of effluent = 17 ppm. M.P.N. of effluent =
460 per ml. This lagoon has a water surface
area of 12. 4 acres, a depth of four feet and
treats the waste from about 1500 persons. A
recirculation pump (85 gpm. ) is provided
which returns to the inlet pipe a volume
approximately equal to the total average
daily sewage flow. The pump is designed
to take suction from any depth in the lagoon.
It would appear that the pump is responsi-
ble for a greater variety of plankton and
possibly a higher dissolved oxygen content
in the lagoon. Insufficient data have been
collected to determine the advantage of re-
circulation.
Operational problems with waste stabili-
zation lagoons in Missouri have been mift-
imum. Some municipal lagoons have ex-
perienced odor difficulties in the spring
following a severe winter. These odor com-
plaints can be satisfactorily handled by the
addition of sodium nitrate applied at the
rate of one pound of sodium nitrate per
pound of B.O.D. Therehave also been some
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problems with blue-green algae in the sum-
mer months. It is our opinion that the blue-
green algae problem can be satisfactorily
handled by the addition of Phygon applied
at the rate of 1 ppm. in the lagoon influent
and around the water edges. We also be-
lieve that breaking up the algal mats by the
use of an outboard motor or pumping equip-
ment will satisfactorily handle the blue-
green algae problem.
Cattails have posed a problem in some
municipal lagoons. The best solution to
this problem is actual removal of the
plants. At Perry, Missouri, there was a
small growth of cattails in the city's la-
goon; however, muskrats solved the prob-
lem by harvesting all of the cattails. The
city then requested the Conservation Com-
mission agent to trap the muskrats.
The proper maintenance of the turf is a
problem; however, the city of Hornersville,
Missouri, has a unique solution to this
problem. Hornersville, a city of 875 (1950
population), in southeast Missouri has a
waste stabilization lagoon with a water sur-
face area of 7. 5 acres'. The turfed dike
area is approximately six acres. The dikes
were seeded with Burmuda grass. In addi-
tion to the lagoon site, the city owns an ad-
ditional fourteen-acre tract adjoining the
lagoon. The maintenance of the turf is pro-
vided by eight cows and a bull. In extreme
dry weather the 14 acres are used to pas-
ture the cattle. The cattle drink the lagoon
water. The city reports that the first
year's calves paid for the cows. The mayor
also reports that the lagoon is stocked with
several species of fish. Soon after the la-
goon was completed in 1956 the dikes were
topped ;by an unusual flood. The city offi-
cials state this flood was responsible for
stocking the lagoon with fish.
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OBSERVATIONS OF WASTE STABILIZATION LAGOONS IN NEBRASKA
by
T. A. Filipi*
In. observing the operation of the 41 la-
goons in Nebraska they would all be per-
fect if it were not for:
Inadequate preliminary study,
Inadequate and improper design,
Faulty construction, and
Lack of operation.
The waste stabilization lagoon in my
opinion has been one of the greatest con-
tributions to sewage disposal that has come
forth within the last several years. I re-
gret very much that we did not boast of the
operation of the Alliance, Nebraska lagoon
which has been in operation for over 30
years. When representatives of the Air
Force observed the operation of this lagoon
during the war they could not understand
how the lagoon could take the overload with
no undesirable effects. Consequently, a
team of scientists was assigned to study
the operation, and all of the claims that
were made for the lagoon were justified.
We, however, failed to make this operation
known. Consequently, other states are now
boasting of the age of their lagoon opera-
tions, but I go on record that our lagoons
have operated successfully long before the
lagoon was even considered.
In the main the results of operations of
our sewage stabilization lagoons are satis-
factory, and there are no complaints from
persons living in the vicinity of the lagoons
The lagoon has been responsible for the
construction of sewage disposal systems
in many a Nebraska municipality because
it permitted the entire construction to be
made at a cost which the community could
assume. In most cases the cost of the dis-
posal of wastes by the lagoon method is
approximately 1/3 to 1/2 that of the con-
ventional plant. Furthermore, there are
many communities in our State which have
no stream for dilution and dependence has
to be made upon soil absorption and upon
evaporation. In checking over the possible
sewer systems for Nebraska it appears
that from now on all sewers that are con-
structed are in a class and in a location
where the lagoon should be seriously con-
sidered as a means of disposal.
Due to one sided publicity, engineers
and municipal officials are assuming that
the lagoon is a panacea for all waste dis-
posal. Therefore, sufficient study is not
being given to the overall problem at hand
and frequently no thought is given to other
means of treatment. In the general sanita-
tion program it is our opinion that there is
still a large field for construction of con-
ventional plants and that a conclusion that
the lagoon will be used before any study is
made is erroneous. For some reason or
other the lagoon has received such public-
ity that frequently when conferring with a
Board of Trustees or attending town meeting
for the promotion of a sewer system the
entire discussion centers around a lagoon.
The sewerage system decision rests upon
ability to use a lagoon. From the stand-
point of a Department of Health we are
most interested in overall sanitation and do
not desire that the lagoon should be of prime
discussion when sewerage is discussed.
Let us give more consideration to the pub-
licity that is promulgated on this subject.
Inasmuch as a lagoon appears to be a very
simple structure in most cases engineers
working in Nebraska do not give sufficient
attention to preliminary studies. Entirely
too many assumptions are being made as to
the quantity of sewage, the strength of sew-
age, it characteristics, chemical analysis
of the waters and other details. There are
four lagoons in Nebraska that at the pres-
ent time are so dry that a person can walk
across the entire structure. Our Depart -
*Director Division of Sanitation Department of Health Lincoln, Nebraska.
144
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ment has not determined whether it is the
lack of sewage or the improper soil prep-
aration of the floor of the lagoon that is the
culprit. However, more preliminary stud-
ies would have corrected the situation. It
is regreted that in the course of sanitary
engineering given in schools and colleges
30 years ago the design criteria of lagoons
was not offered. Therefore, there is much
to be desired in the design of the lagoon in
all of its details, the inlet, the splash plate,
the location of the inlet, the number of
cells, control structure, overflow struc-
tures, soil mechanics of the lagoon floor
and the dikes of the units when finished.
Undoubtedly, the engineers of Nebraska are
quite frustrated because of the amount of
literature that is being sent to them on the
subject from the Health Department much
of which is in contradiction with a previous
directive. Yet, there is no new principle
in the lagoon that is not enveloped in some
of the basic courses taken by an engineer
either in college or could be read through
current literature. However, I believe that
the design of lagoons is sadly overlooked
because of erroneous ideas.
In the area of design we cannot over em-
phasize the need of more study being given
to the soil. We are now convinced that a
complete soil survey should be made of the
lagoon site, samples taken, analyzed by a
reputable laboratory and formulation for
the various areas made up to insure the
specific quality of soil needed for the spe-
cific purpose. This then will insure proper
water holding characteristics, prevention
of soil bank erosion, and proper seeding
of desired areas. The mere compaction to
90% Proctor density is not sufficient to give
the desired results. Futhermore, tests
should be made on the finished structure
and adjustment's made if necessary. Spec-
ifications will have to be altered to permit
the performance test to be the governing
characteristics rather than the mere mat-
ter of construction.
Due to the fact that the lagoon is so sim-
ple a structure, has no pumpg, motors,
air compressers, aerators, and other
equipment the municipal officials are prone
to neglect hiring of proper persqnnel and
giving them sufficient time to properly
maintain a lagoon. At the present time in
discussing the lagoon withpersons intending
to install one we state that a lagoon operator
should be as qualified an individual as one
operating a conventional plant. In a con-
ventional plant the operator can control his
environment. That is, he can increase the
speed of the air compressors, he can
change the flow from tank to tank, he can
increase or decrease his suspended solids,
can vary the alkalinity, or acidity of any
process and in short control the various
phases in the plant. In a lagoon the oper-
ator must obey nature and first learn na-
ture's laws and then co-operate. It is very
much similar to the operating of a sailboat
versus a power boat. In general the design
and construction criteria could be overcome
if good operation was insured. Here again,
a plea is made to the engineers and possibly
the publicity and promotional people of pop-
ular magazines to stress the need of oper-
ation rather than stress the simplicity re-
quiring no attention. Furthermore, stress
should be given to preventive maintenance.
At the present time we have several la-
goons in Nebraska where erosion has cut
the banks to forming ravines 30 inches
deep. If the operator was interested in his
assignment and would have visited this la-
goon daily as is our instruction this ravine
could have been corrected with perhaps one
or two shovels of dirt and a hand full of
seed by avoiding the terrific job rebuilding
the entire dike. If the operator would have
pulled out the willow on the bank of the la-
goon while a sapling it would have avoided
cutting down a tree with a power saw. If
weeds that are emerging just off the shore
line were pulled it would have prevented
their spreading into the lagoon and making
necessary removal by means of a barge or
boat. We cannot emphasize too greatly the
need of simple daily consistent maintenance
and operation.
We are insisting that lagoons be placed
one half mile from town and a quarter of a
mile from the closest inhabitant. Therefore,
even though our personnel have found la-
goons that are infested with mosquitoes,
have an odor, have eroded dikes, have
a growth of trees along the shore line and
many other items which are against general
lagoon operating principles we still do not
have a growth of trees along the shore line and
therefore, take the stand that the lagoon
will be placed far enough away from town
and be left to deteriorate as is possible and
not worry the municipal officials and es-
pecially the operator of proper maintenance.
Jealously we have been endeavoring to
have lagoon maintenance of such type so
that when municipal officials of communi-
145
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ties planning lagoons would visit them they
would go away enthusiastic about the struc-
ture. I regret that time did. not permit to
show photographs of some of the lagoons
that we have which will I am sure unsell
any prospect. Yet, when these people dis-
cuss the lagoon with municipal officials
they are assured that in spite of the mos-
quitoes, the weeds, the trees, the erosion
and odor that the lagoon is far enough from
town that no one seems to complain.
Another observation that appears to be
common with all lagoons is that of esti-
mating future growth. It is our opinion that
a lagoon should be constructed for the im-
mediate load and that only. We are finding
that lagoons that are constructed and not
used, deteriorate to such degree that if
they ever will have to be used the entire
structure will have to be rebuilt. We would,
therefore, suggest to municipal officials
that a lagoon is a cheap means of disposing
of sewage and that they construct that facil-
ity that they need at the present time with
the understanding that when the original
structure is overloaded that another cell
will be constructed. Working with mu-
nicipal officials in this matter, is of course,
difficult because by the time the first unit
is loaded another Council is in power and
just cannot see why at the end of 5 to 6
years the facility is over loaded and needs
expansion. They completely forget about
the arrangements and agreements that
were made even though in writing.
The lagoon in our opinion is serving a
useful purpose in disposing of domestic and
industrial wastes and has been responsible
for much sewerage installation and for
much abatement of pollution of our streams.
However, it is our opinion that the lagoon
at the present time is on too low a level of
engineering status and perhaps too low on
the operational level of municipal utilities.
Consequently, it is not receiving the seri-
ous attention in the design, construction
and operation. If we can elevate the status
of lagoons to that of a trickling filter plant,
an activated sludge plant, or perhaps chem-
ical recipitation giving it serious consider-
ation in all details I am sure that more la-
goons will be constructed and the operation
phases of all details will be satisfactory to
not only the stream pollution control author-
ities, but to the Health Department officials
and to the persons in close proximity of
these lagoons.
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SUMMARY OF THE OPERATIONAL HISTORY OF RAW SEWAGE LAGOONS
IN THE STATE OF COLORADO
by Ronald C. McLaughlin*
One approach to one establishment of de-
sign criteria for the construction of new
sewage stabilization ponds, is to evaluate
the operation of existing functioning ponds.
In attempting this, we relied mostly on the
opinion of the Department's District Engi-
neers who service the particular areas and
have the closest personal contact with the
individual facilities. Using the interpreta-
tion of several engineers naturally may
lead to variation of results, but this was
minimized by defining the physical charac-
teristics as closely as possible and by re-
viewing individual attitudes.
Many variables other than loading e.g.
pond shape, operational control, climato-
logical differences (considerable due to the
altitude changes in Colorado), waste char-
acteristics, etc., undoubtedly have effected
the comparative operation of these lagoons.
It was hoped that a study of the histories of
a sufficient number of ponds would show a
pattern even though large data variances
were present.
A list of communities with individual fig-
ures used is shown in Table 34. Operational
information only, on 25 ponds in the State
of Colorado was used in the analysis. Our
Design Standards call for a water depth of
between 3 and 5 feet and all of these ponds
are so designed.
A plot of loading versus operation history
classification is shown on Graph A.
Interpretations made from Graph A must
be thought of as approximate and consid-
ered only as observations of limited data.
The following observations were made:
1. 60% of the ponds in Colorado are op-
erating in a loading range of 100-200
persons per acre.
2. Of the ponds thatare operating at 100 or
less persons per acre, loading 100%
(4 out of 4) were classified as good or
excellent.
3. Of the ponds operating at a loading
from 101 through 200 persons per
acre, 86% (12 of 14) were classified
as good or excellent. 14% (2 of 14)
were classified as fair or worse.
4. Of the ponds operating at a loading
above 200 persons per acre, 29% (2
of 7) were classified as good or ex-
cellent. 71% (5 of 7) were classified
as fair or worse.
5. Without having made a specific study
of a conventional type plant, it is
known that ponds as a method of
treatment would have a much better
average operational history classifi-
cation than the conventional plant fa-
cilities in Colorado.
See following page for:
(Table 34, SUMMARY OF THE OPERA-
TIONAL HISTORY OF RAW ^EWAGE
LAGOONS IN THE STATE OF COLO-
RADO)
•Division of Sanitation, State Department of Public Health.
147
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TABLE 34
Summary of the Operational History of Raw Sewage Lagoons
in the State of Colorado
COMMUNITY
Burlington Sanitation
Colo. Training School
for Girls -Morrison. •
Frie
Erie Series Oper-
Frederick (Tri-Area). • •
Wrav.
Est . Tributary
Population Equiv.
5 400
3 500*
700
400
250
350
450
430
150
4 500
1 200
1 300
780
780
1 200
1 200
1,200
325
800
10 000
3 600
400
500
100
2 400
1,800
42 935
Area
Acres
47
20
4.2
p.O
2.5
1.35
3.0'
1.92
0.5
27
14.3
6 1
3.4
1.75
3.1
6
8.3
4.5
6
96.6
38.9
or
27.1
2.0
1.0
5
ip 3
9.0
325.97
Loading
Pop/Acre
115
175*
165
pnn
100
260
1 <5Q
2?5
300
165
85
013
220
450
390
200
145
75
133
103
110
200
500
20
-105
200
AYC •
= 132
General
Classification
of Operation*
Good
Poor
Good
Good- (2-2 1/2 acre
ponds ) 1-pond in
operation 1/2 of
town is hooked on.
Fair
flood
Good
Poor
Fair
Excellent
Good
?
Poor
Poor to fair
Good (except when
slaughterhouse was
connected)
Good -exc e llent
Good
Good
Exo*3 1 1 f^Tit
Good
Excellent
Fair— expansion
in 1960
flonrl
Good
Ave .
= Good
*Pond Operation Classifications
148
-------
Choose the classification most nearly describing the ponds.
FAIR - Almost continuously anaerobic v.ith odor nuisance and/or health hazard.
No D.O. in effluent.
Effluent not complying with state standards - BOD greater than 50 ppm.
POOR - Frequently anaerobic with odor nuisance and/or health hazard.
Effluent does not comply with 30 ppm.
BOD concentration standard.
FAIR - Anaerobic occasionally (more than 1 or 2 weeks per year) with some odor com-
plaints .
Effluent normally expected to meet standards with exception of coliform MPN.
GOOD - Only anaerobic for short period in Spring.
Effluent expected to meet state standards.
Evidence of good biological growth continually.
EXCELLENT - No record of odor complaints (aerobic operation).
Effluent, if any, meets state standards.
Always good biological growth in ponds.
149
-------
o
H «H
CO O
M
-p
CO
PH -H
O
M
S3
o
CO
a
aad suosaaj -
150
-------
EXPERIENCE IN WYOMING WITH WASTE STABILIZATION LAGOONS
by
David P. Green*
The waste stabilization lagoon is an ac-
cepted method in Wyoming, for the treat-
ment of both industrial and domestic
wastes. These units are considered to pro-
duce a degree of treatment equivalent to
the conventionally accepted methods of
secondary treatment.
The following discussion will treat the
subject first in terms of factors required
by climate, terrain and other natural con-
ditions; secondly will deal with a few rec-
ommended design considerations which
experience has indicated to be desirable;
and thirdly, by a brief discussion of ex-
perience, both favorable and unfavorable,
with such lagoons in Wyoming in the re-
cent past.
Wyoming, for the most part, is an arid
state, having extremes in temperature.
Freezing conditions and snow may be ex-
pected from October to late April, al-
though long periods of intense sunshine are
common and mitigate the often severe win-
ter conditions. As might be expected, the
low humidity and intense sunlight, coupled
with relatively high wind velocities, re-
sult in high rates of evaporation.
Both industry and municipalities are,
for the most part, concentrated in the
river valleys, such as those of the North
Platte, Green and Big Horn Rivers. The
river valleys are generally narrow and
boarded by desert; or at least near desert
country. It will be realized that this type
of topography, together with the sparse
population, has made the waste stabiliza-
tion lagoon a preferential method of treat-
ment. This is shown by the pollution
abatement program which has resulted in
the construction of 46 municipal lagoons
since 1955, while only 4 conventional
plants have been built during the same
period. Acceptance of the waste stabiliza-
tion lagoon has been even more marked
with industry private corporation.
The Wyoming design criteria for lagoons
generally follow those suggested by the
Missouri Basin Engineering Health Coun-
cil. Allowable BOD loadings for raw sew-
age lagoons are shown as a population
equivalent of 200 persons per acre (35 Ibs.
per acre). Thus far, theoretical consid-
eration has shown no necessity for the
development of specific criteria for reten-
tion or hydraulic loading for conventional
organic wastes where the stabilization of
the oxygen demand and reduction of bac-
terial population are desired.
Design practice calls for operation at
two depths, 3 feet during the summer and
5 feet during the winter months. These are
primarily an empirical pair of values. The
lesser depth is based partially on experi-
ence in preventing the growth of rooted
aquatics providing circulation and partially
on some studies conducted several years
ago concerning light transmission thru al-
gae bearing waters. The winter depth is
almost solely empirical and represents an
attempt to compromise the recognized ef-
fect of temperature on the reaction velocity
constant for "anaerobic" or heterogeneous
conditions brought about by the "Blackout"
of solar energy due to ice and snow cover,
as against the increased cost of construc-
tion if a specific high degree of treatment
were to H= mandatory.
Several very limited investigations have
been made of the location of inlets and outlets
There seems to be a definate indication that,
at least in small units, i. e. under lOacres,
an effect is exerted by prevailing high winds
causing some short circuiting. The data are
insufficient for conclusion to be drawn, but it
is suggested that considerationmight be given
to these factors of wind direction and velocity.
•State Department of Public Health Sanitary Engineer.
151
-------
The location of population centers in
river valleys has led to the problem of
sealing lagoon bottoms in many cases.
Originally a literature search was made,
however, it was felt that'the majority of
the work, having been done on irrigation
canals, was not applicable to lagoons since
velocity conditions, etc. are not encoun-
tered.
Several methods of sealing have been
used in Wyoming, and all are apparently
equally sucessful, the choice being eco-
nomic. These are the installation of a 4 -inch
true clay blanket, the use of a seal coat of
crude bentonite worked into the surface of
the bottom, and by asphaltic soil stabiliza-
tion. In the last case, an MC-oil or RC-oil
has been applied by distributor for a total
application of 0. 5 to 0. 7 gallons per square
yard. Interior banks are treated either by
hand hose or an adapted spray bar.
Since the pollution of shallow ground
water does not constitute a problem, in
Wyoming, it is our opinion that the seal
must be effective for a period of 6 to 12
months, after which we believe that accumu-
lated algae and sewage solids will effec-
tively plug the soil interstices forming the
equivalent of an impermeable membrane.
The great majority of lagoons in Wyo-
ming are of the multi-cell flow thru type
with piping arrangements for either series
or parallel operation. Although a few com-
plete retention lagoons have been designed
for areas where either no defined drainage
exists or for specific industrial problems
where a discharge could not be tolerated.
Despite calculation these units may have
to be enlarged as experience dictates.
More recently variations have come into
limited use, as for example at the Jeffrey
City Townsite of the Western Nuclear Com-
pany. In this case the units are slightly
modified and field irrigation effectively
supplements the lagoons.
Recently it came to our attention that
operating difficulties were being experi-
enced in multi-cell units. Our investiga-
tions indicated that these units were not
being loaded on the basis of surface area.
Therefore we now require that all multi-
cell units be provided with some type of
flow measuring device on the inlet. Flow
measuring devices on outlets might also be
considered where such information might
be of value in material balances. I would
like to add that, in my opinion, series op-
eration during our long cold weather pe-
riod, would tend to increase benthal loads
unduly in the spring.
Another item which is too frequently
overlooked is that of composition of the
wastes. A simple example of this is the use
of lagoons for secondary or tertiary treat-
ment after some type of pretreatment. We
have found, for example, that small lagoons
are valuable following septic tanks at
trailer courts, or after sedimentation in
several small towns. In these cases it must
be realized that the criteria should reflect
the removal of the nonsoluable BOD, and
therefore that the units can logically be
smaller.
Many industrial wastes will require some
type of pre-treatment, although lagoons
can and do adapt to a surprising degree.
Studies must be made of the composition
of the waste, the sources for specific com-
ponents, the effect and reliability of the
methods of pre-treatment, the effect or
normal and possible shock loads on the la-
goon and finally the compatibility of the
waste to the lagoon method of treatment
and the degree of stabilization expected
under varying conditions. A few examples
of pre-treatment are as follows:
1. Packing House Wastes: All possible
blood, paunch manure and solids
must be retained in the plant. This
is not a new waste and recognized
methods have been developed for
proper in plant housekeeping. Fail-
ure to carry out such a program
would not only require an inordinately
large lagoon system, but would re-
sult in the formation of floating scum
mats and possible effective blackout
of the pond due to coloration. These,
of course, create nuisance conditions
as well as generally result in an un-
stabilized effluent.
2. Petroleum Wastes: Toxic substances
and oil must be reduced to the prac-
tical minimum prior to discharge to
a lagoon. Where possible total reten-
tion systems or adaptations of those
systems should be used.
3. Wool Scouring Wastes: Recently the
Wyoming Department of Public Health
152
-------
was required to evaluate waste sta-
bilization lagoons as a possible
method of treating this type of waste.
A literature search and chemical
analysis determined that this waste,
had an extremely high BOD, oil and
grease, and solids content. The prob-
lem was further complicated by the
use of a very high concentration of an
industrial non-ionic detergent. Con-
sideration of all possible methods of
pre-treatment did not indicate that
the waste load, particularly the de-
tergent, component, could be treated
by the lagoon method, to say nothing
of providing a satisfactory effluent.
It is believed that the remainder of this
discussion could best be devoted to a dis-
cussion of specific problems encountered
within the last three years. I would like to
point out that the laboratory facilities of the
Wyoming Department of Public Health is
extremely limited and that only a bare min-
imum of the data considered desirable has
been obtained.
Various difficulties have been experi-
enced with municipal waste systems. Il-
lustrating examples are as follow:
1. In the first case: This particular unit
had been designed as a one cell flow
thru unit based on 1 7 Ibs. of BOD per
acre, and operable at both 3 and 5
foot water depth. The unit had a rec-
ord of completely satisfactory oper-
ation for two years. The lagoon
failed going into anerobic condition
suddenly. Insofar as was known, no
industrial wastes had been recently
accepted into the system, nor had
there been any great increase in pop-
ulation served. A small amount of
oil was noted on the leeward end of
the unit, but the Town had an en-
forced regulation against discharge
of waste oil to the sewers.
Eventually a leak was discovered in
a short section of crude oil pipeline
passing near the lagoon.
Sufficient oil had been discharged to
the unit to create a toxic condition,
without causing large areas of oil on
the surface. Practice now requires
that such lines are relocated.
2. The 2nd case: It concerned a one cell
flow thru unit designed on the basis
of 35 Ibs. of BOD per acre and capa-
ble of operation at 3 and 5 foot water
depth. During the late summer of
1958 an inspection found that the la-
goon had failed. The lagoon water
was found to be a deep red and ap-
proximately 1/8 of the surface was
covered by a floating scum mat. As
previously, the northern series pair
showed aerobic or probably truly
facultive conditions with the degree
of treatment increasing from interior
to exterior cells. An overall BOD
reduction of 82% was achieved by
aerobic conditions under an average
of 50% ice cover at water tempera-
tures just above freezing.
The Southern pair was found to be
"Anaerobic" - or at least lacking in
dissolved oxygen as determined by
standard analysis. Algae were pres-
ent, however, in lesser numbers than
in the other pair, but in sufficient
quantity to indicate a heterogeneous
type of stabilization. t^S generation
was marked. Although the overall
BOD removal was 78% with this pair,
the degree of removal lessened as
flow progressed from interior to ex-
terior cells. It had been found in the
study that sewage flow was split to
the lagoons on some basis other than
loading per surface acre. Apparently
this incorrect distribution over a pe-
riod of time among the cells produced
sufficient benthal decomposition due
to temperature effects on the rate
constants to cause this situation to
occur.
On the whole, few difficulties have been
experienced with industrial waste stabili-
zation lagoons. I belive that others have
have discussed a majority of industrial
waste problems, therefore only two ex-
amples are presented.
1. Standard Oil Company, Casper: This
is a large full line refinery. All
wastes after oil reclamation and
housekeeping procedures are dis-
charged to a large retention area.
Phenols seem to be almost totally
removed and treatment appears to be
excellent. No ground water problems
153
-------
are encountered and no return water
is discharged to the North Platte
River, but is disposed of byevapora-
tion and percolation.
2. Western Nuclear Corporation, Jef-
frey City: This plant processes ura-
nium ore under AEC license. A total
retention lagoon has been constructed
for mill wastes which would other-
wise be discharged to the Sweetwater
River, causing radio-nucleide chem-
ical and physical pollution.
Investigation found that a packing
house had been given sewerage serv-
ice several days previously and that
no pretreatment had been required.
Although the packing house was
small, the discharge of raw waste
had raised the influent BOD loading
on the lagoon to nearly 100 Ibs. per
acre. This of course was corrected
by pre-treatment, but it is interest-
ing to note that the lagoon was anaer-
obic only at night; the aerobic-anaer-
obic cycle lagging the day-night cycle
by approximately 2 hours.
3. The 3rd example concerns a 4 cell
unit serving approximately 18,000
people and designed on the basis of
30 Ibs. of BOD per acre. The flow
arrangement in this particular unit
is unusual. Raw sewage is loaded in-
to all cells. Two interior cells then
over flow into the remaining two ex-
terior cells. The only unusual indus-
trial waste is a small wool scouring
pilot plant operated on an extremely
limited basis for 2 months during the
summer. This system has been found
to have anaerobic conditions in 1
series pair and aerobic conditions in
the other in the spring of 1959. Al-
though surface effluent discharge is
provided, this could not account for
variations within the unit.
Since this is the largest unit in the
state and good laboratory and tech-
nical facilities are readily available
a study was planned for 1960. The
study would include BOD, DO, Nitro-
gen series, phosphate, oil and grease,
detergent analysis and biological and
bacteriological work. The first sam-
pling series was planned for the
spring ice-break-up in I960.
The unit is radiologically monitored
and is well below the accepted ex-
posure values. No significant change
is found in radioactivity or in ni-
trates in the ground water.
In summary I wish to present the under-
lying ideas of the proceedings: that a ra-
tionale should be developed for the use in
the design of waste stabilization lagoons
for specific situations and furthermore that
the lagoons are merely another type of
treatment which may be preferable in a
specific situation.
154
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ARCTIC SEWAGE LAGOONS
by
Charles F. Walters*
The Arctic Health Research Center has
been observing two experimental sewage
lagoons in Alaska for the past three years.
Design recommendations of the Center
engineering staff were followed by consult-
ing engineers in the preparation of plans
for both installations. Under AHRC sponsor-
ship the Alaska Department of Health ap-
proved the lagoons on an experimental
basis to permit observation of the effects
of extreme climatic conditions, including
long periods of thick ice cover.
One of the lagoons, located at Sutton,
Alaska (60 miles from .Anchorage), was
designed for a population of 50 persons from
a roadhouse and adjacent trailer court.
The area of the unit, based on a loading of
200 people/acre, is 1/4 acre. The normal
summer operating depth is 3 feet, however,
provisions was made for a winter storage
to a depth of 5 feet.
The lagoon did not hold liquid during the
first two years of operation despite several
attempts to seal the bottom. Silt from a
nearby stream was diverted to the lagoon
but subsequent retentions lasted for only a
month, after which time the lagoon would
again empty. Although there was an ac-
cumulation of sludge around the center in-
let, no odors were detected.
The other experimental lagoon, located
at Ft. Yukon, Alaska (150 miles north of
Fairbanks) was designed for an elementary
school serving 200 non-boarding children
and 8 adult teachers.
A 1, 100 foot, 6 inch, wood stave pipe
carried the sewage from a sump in the
schoolhouse to the inlet structure in the
middle of the 125 foot square area. Although
an overflow was provided at the 5 foot level,
no effluent has been discharged since sew-
age first began entering the lagoon in 1957.
Based on a population of 200, the loading
for this lagoon is 425 people/acre. Obser-
vations on the number of sump pump dis-
charges indicate a daily discharge of 2, 200
gpd. The detention period at the 5 foot level
is one year. Percolation and evaporation
maintain the level at approximately 2. 5
feet.
Severe winter temperatures of -60°F
have not affected the flow of liquid in the
sewer line. The reason for this is twofold:
initial pumping temperature and intermit-
tent pumping. The sewage has an initial
temperature of 60oF when it leaves the
sump in the school house and is pumped
intermittently to the lagoon.
During the winter 1957-1958, ice thick-
ness varied according to the distance from
the center inlet. Directly above the inlet
there was no ice, whereas near the shore,
the lagoon was frozen solid. The following
spring as the ice melted and began to rise,
it carried with it the horizontal inlet pipe
and broke off a section near the shore.
Consequently, the lagoon froze solid the
following winter except for an area 25 feet
in radius around the shore inlet.
During the spring transitional period of
1959, samples obtained for plankton iden-
tification indicated that the sewage organic
matter in the top 9 inches of the lagoonwas
stabilized in one month after the ice left the
pond (l). An analyses of dissolved oxygen
content in tne spring of I960 tended to sub-
stantiate this belief. Hourly samples col-
lected over a 24-hour period showed the
lagoon in a continuous state of dissolved
oxygen saturation. Figure 11 is a compari-
son of these results with the diurual fluc-
tuations reported by Towne etal (2) in their
North Dakota studies. Since an abundance
of oxygen is available consistently instead
of intermittently, it would be expected that
•Sr. Asst. Sanitary Engineer, Arctic Health Research Center, Public Health Service, Anchorage. Alaska.
155
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40-
O
CO
-------
an arctic lagoon could support a larger
bacterial population, resulting in a shorter
period of stabilization for any given amount
of B.O.D.
The stabilization lagoon at Ft. Yukon is
unique in that it is loaded only during the
winter months, at which time an adequate
ice cover prevents the spreading of obnox-
ious odors. Following the disappearance of
ice in the spring, it appears that complete
stabilization is attained within one month.
The biological mechanisms responsible for
such an accelerated reduction of wastes is
contingent upon the long daylight hours
which provide the necessary solar radia-
tion for photosynthetic activity in the algae.
Because of the vast land area in arctic
and subarctic regions, the use of lagoons
in Alaska presents an inexpensive means
for treating domestic sewage. It has been
shown that successful lagoon operations
can be maintained even in such adverse
climatic conditions as might be found in
Ft. Yukon, Alaska.
REFERENCES
(1) Anderegg, J. A., Walters, C.F.
Milliard, D., Meyers, H.F.,
"Eskimo Algae Make Lagoons Work
at the Arctic Circle", Wastes Engi-
neering, 31,6, 324 (June I960).
(2) Towne, W.W., Bartsch, A.F., Davis,
W. H., "Raw Stabilization Ponds in
the Dakotas", Sewage and Industrial
Wastes, 29,4, 377 (April 1957).
157
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IMPROMPTU REMARKS MADE
by
Joe Williamson, Jr.
This meeting has resulted in being the
most important three day session I have
ever attended in my 31 years in sanitary
engineering. To you who are present I say
you are lucky, because you are seeing his-
tory made here.
In school I studied Babbitt, edition of
1928. It takes a good three years to com-
pile the data, write, edit, print and mar-
ket a textbook on such technical subjects .
as""Sewerage and Sewage Treatment". It
might be said, therefore, that Babbitt,
edition of 1928, truly presented practices
in the field in the mid-twenties. It has
often occurred to me that, in basic I960
sewage treatment plant design I could refer
to said edition of Babbitt and design a mod-
ern plant. In that book were described
trickling filters with rotary distributors;
activated sludge; chemical precipitation;
separate, covered, mechanized digesters
with gas collection for heating; centrifuges
for drying sludge (now experiencing, at
long last, a new awakening); acidulation or
acidification of sludge; sludge vacuum fil-
ters; acid precipitation; electrolysis; dis-
infection; etc., etc.
May I digress to say that in 1925 trick-
ling filters were new and sanitary engi-
neers were not quite "sure". In the begin-
ning many engineers were violently opposed
to filters. To quote Babbitt: "In the sum-
mer the filters sometimes give off offen-
sive odors that can be noticed at a distance
of half a mile, and flying insects may
breed in the filter in sufficient quantities
to become a nuisance if preventive steps
are not taken". Even today it must be ad-
mitted that the "hands and knees" method
detecting odors from conventional plants is
far from being necessary, but always is
with well designed and well maintained ox-
idation ponds.
The point I am making is that, for the
best part of 35 years, there has been no
major "break through" or real, practical
revolutionary advancement in the art of
sewage treatment as has been the case in
practically every other field of modern en-
deavor. Would you not split your sides
laughing at the sight of a 35 year old auto-
mobile creeping down the street? Yet, we
are designing economically prohibitive
treatment plants the basic ideas for which
were all in practical application thirty-five
or more years ago. This is a horrible con-
demnation of our profession.
At this meeting I do believe we are tak-
ing a good look at the first real "break
through" unless one other very recent ad-
vancement could fall in that category. I
refer to vacuum filtration of all raw
sludges, primary and secondary, to elim-
inate the major headaches and the major
operation expense in any plant; ie, conven-
tional sludge digesters and sludge drying.
In the past I have heard many discus-
sions on the subject "why has the art of
sewage treatment been so retarded"? I
have even myself been a party to the
thought that most of the lack of progress
may be due to some public health officials
insisting on seeing anything tried in some
other state fifteen years prior to approval
in their states. After this meeting I will
never again subscribe to such thoughts. I
say this because consulting engineers,
writers of our textbooks and our long-
haired professional aristocracy who influ-
ence our thinking have all been asleep on
the subject of oxidation ponds for stabili-
zation of sewage. It has consistently been
the public health officials in this country
(down at the grass-roots level, where they
know the importance of "cost") who have
carried the torch in insisting on recogni-
tion and acceptance of waste stabilization
lagoons.
Back in 1942, and I repeat, in 1942,
(eighteen years ago) one public health offi-
cial had then been crying from the house
tops for some years and no one listened. In
159
-------
1942 C. G. Gillespie, Chief, Bureau of
Sanitary Engineering, California State
Dept. of Public Health made the following
statements to the Arizona Water and Sew-
age Association:
"That oxidation ponds are not more used
can be explained by their crudity com-
pared to neat engineering structures, the
unattractive green coloration of the efflu-
ent and perhaps by the fact that too few en-
gineers are aware of the potentialities of
oxidation of organic matter. Properly laid
out for size and embodying a. few simple
details, oxidation ponds absorb and de-
stroy the odors of sewage, leaving nothing
worse than the smell of a swamp. The ef-
fluents are permanently stable, with BOD
values as good or better than those of
trickling filter effluents. As a destroyer of
sewage bacteria, they possess almost un-
believable efficacy. Final overflow from
ponds designed for 15-day detention will
show 5-50 B coli. per cc compared to
something like 100,000 per cc in the orig-
inal sewage. Such results continue day
after day and therefore will rank with, or
outrank, results from chlorination in reli-
ability. "
Obviously, prior to World War II, some
few of us had considerable knowledge of
the application and efficiency of oxidation
ponds. Even so, we went right ahead de-
signing temporary, emergency, conven-
tional activated sludge and trickling filter
plants for hundreds of Army and Navy can-
tonments utilizing tons of steel and other
critical materials that should have gone
into battleships. In a communistic state
such neglect and lack of vision, especially
in war-time, would have resulted in many
of us being lined up against a wall and shot.
This meeting we are attending here is
the sole result of the blood, sweat and
tears of a few dedicated public health offi-
cials, such as Gillespie of California;
Svore and Van Heuvelen of North Dakota;
Hopkins of the P.H.S. ; Ehlers of Texas;
and, more recently, Brinckof Montana, our
own Jack Smith of Missouri, Carl of South
Dakota, Filipi of Nebraska, and Johnson of
Mississippi. Out of dire necessity these
men and a very few other public health of-
ficials have been forced to take over the
leadership of our heretofore leaderless
profession. How much longer are such men
to be castigated by our reactionaries who
believe no process has any merit unless it
involves a three story masonry structure
of huge cost upon which can be mounted a
bronze plaque in their memory?
Admittedly, this is a terrible condemna-
tion of our profession. Even so, I believe
that too many of us have been keeping our
mouths shut too long for the best interest
of the American taxpayer. A rude awaken-
ing is in order.
160
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CRITIQUE
By C. H. Atkins*
Although the title of this portion of the
program is "Critique, " the following is not
intended to be so complete and thorough as
to warrant such a title. Neither will it be a
summary. In fact it will consist of some
conclusions your speaker has drawn from
the information presented at this Sympo-
sium.
The Missouri Basin Engineering Health
Council has demonstrated real leadership
in sponsoring this Symposium. The attend-
ance of more than 300 persons concerned
with water quality management from 32
States and 8 foreign countries indicates the
tremendous interest in lagoons. This Sym-
posium has afforded an excellent opportu-
nity for the interchange of information on
this relatively new concept in sewage treat-
ment.
During this Symposium there have been
various reports as to the time and place of
the early pioneering work on the use of la-
goons for sewage treatment. Much of this
work was directed toward the use of la-
goons in connection with conventional treat-
ment processes. The use of lagoons for
treatment of raw sewage began to get un-
derway in this country about 1950.
This method of raw sewage treatment
has been accepted by each of the 10 State
Health and Water Pollution Control Agen-
cies of the Missouri River Basin, the same
agencies in other States, and by the U. S.
Public Health Service. Under Public Law
660, construction grants have been made
since early 1957 for 443 projects in 32
States for waste stabilization lagoon proj-
ects. Of these 432 were for raw sewage
lagoons. The rate of growth in the utiliza-
tion of this method of sewage treatmenthas
been great and is accelerating.
One of the factors favoring waste stabili-
zation lagoons is lower capital and operat-
ing costs. The information presented dur-
ing this Symposium indicates that the
capital cost ranges from 40 to 60 percent of
the cost of conventional secondary treat-
ment facilities. Population served, land
costs, and many other factors affect this
ratio. The operational costs are substan-
tially less than for other types of treatment.
These costs, however, are not zero. The
lagoons must be given proper maintenance
as is required of other treatment processes.
Reports from several State Health De-
partment representatives indicate that the
use of lower cost waste stabilization la-
goons has accelerated the construction of
sewer systems as well as treatment facili-
ties. This is very significant from the pub-
lic health standpoint. The elimination of
insanitary conditions in communities and
the improvement of water quality are high
priority items in environmental health
programs.
While this Symposium has been directed
primarily to the use of lagoons for the
treatment of raw sewage, there has been
some discussion of other uses of lagoons.
These include "polishing" of the effluent
following conventional primary or second-
ary treatment. Another use is anaerobic
lagoons for very high B. O. D. wastes such
as that from meat packing plants followed
by aerobic lagoons for final treatment.
Encouraging reports were made on re-
search by industry, universities, State and
Federal agencies. The results of this work
thus far, however, are meager in terms of
needs. Research, evaluations and demon-
strations are essential in the further de-
velopment and use of waste stabilization
lagoons to enable realization of their full
potential. High priority should be given by
each of us in the support of more research
by industry, universities, State and Fed-
eral Water Pollution Control Agencies and
•Regional Engineer, U. S. Public Health Service, Region III, Charlottesville, Virginia.
161
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others. Pending the results of this re-
search, we already have studies and oper-
ational experience necessary to enable a
rational approach in the design and opera-
tion of lagoons for sewage treatment. The
States of the Missouri River Basin have
developed criteria on this basis. These
criteria, which were presented at this Sym-
posium, represent a major step in the es-
tablishment of design standards and opera-
tional practices. Variable climatic and
other conditions make it necessary to pro-
vide considerable latitude in such criteria.
One State indicated that rainfall and evap-
oration were so different within the State
as to require variations in design depending
upon the location within the State.
Special studies and operational experi-
ence indicate that the efficiency of lagoons
is comparable to secondary treatment in
terms of B. O. D. reduction and that the re-
duction in coliforms and nutrients is
greater than for conventional secondary
treatment. In many instances, lagoons are
used for complete retention of effluent for
periods when receiving stream is critical.
Holding periods up to 120 days are pro-
vided in some States during ice coverage of
the streams and resultant low oxygen con-
tent. In some instances lagoons are appli-
cable for complete containment of the sew-
age. They have shown unusual capability to
absorb shock loads and to handle widely
fluctuating waste discharges.
An example of complete containment of
sewage effluent through the use of lagoons
is the interim treatment works under de-
sign for the Dulles International Airport
near Washington, D. C. This airport is
located in the Potomac River Basin up-
stream from the Washington water works
intakes. Public Health, aesthetic, and other
considerations made it desirable to have no
discharge of sewage effluent from the air-
port above the •water intakes on the Potomac.
A large interceptor is to be constructed
along the river to carry sewage from
the airport and other upstream areas to the
Washington sewage treatment plant. Pend-
ing the completion of this interceptor, the
airport sewage will be treated in lagoons.
It is anticipated that there will be no over-
flow from the lagoons for one to two years
after they are placed in operation. Subse-
quently, the lagoon effluent will be dis-
charged onto the land on airport property by
spray irrigation.
Satisfactory results have been reported
for waste stabilization, lagoons used for
communities up to 15,000 population. Some
are now under construction or being planned
for towns of 30, 000 to 40, 000 population
plus the industrial wastes discharged to
these municipal sewer systems. Likewise,
this method of treatment has been demon-
strated as suitable for small communities,
schools, motels, resorts, slaughter houses,
rendering plants, creameries, laundries
and oil refineries.
The waste stabilization lagoons are not a
panacea for all sewage treatment problems.
The availability of land required for la-
goons to serve large cities may be a limit-
ing factor. Mosquito breeding may occur
unless the lagoons are properly constructed
and maintained, but no significant breeding
was reported in lagoons properly designed
and operated. Odors appear under certain
conditions most of which may be due to
improper design or operation. Certain
types of industrial wastes interfere with the
biological process in a manner similar to
other biological treatment processes. Land
values, topography, permeability of soil,
high ground water table, climate and other
factors should be considered in the selec-
tion and design of this type of facility.
Our explosive population and industrial
growths have placed unprecedenteddemands
on our water supply resource. Forecasts
indicate that these will continue at an ac-
celerated pace. These are factors under-
lying the growing public support for water
pollution control. There is considerable
competition for funds, and adequate treat-
ment facilities are expensive for any com-
munity. It is a great challenge to meet
these demands and needs. Waste stabiliza-
tion lagoons have demonstrated successful
use from the southern to the most northern
boundary of the United States. From the in-
formation presented at this Symposium, it
is concluded that this treatment process,
when properly designed and operated, will
work satisfactorily in any of our soil and
climatic conditions for any size community.
The determining factor, therefore, is the
relative cost of construction and operation.
Consequently, this method of sewage treat-
162
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ment should be considered along with other The Missouri Basin Engineering Health
proven processes in making the engineering Council has rendered a valuable public
and economic analyses which should govern service in providing extensive information
the selection of the most suitable type of on waste stabilization lagoons through the
treatment facility. mechanism of this Symposium.
163
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SELECTED REFERENCES ON
WASTE STABILIZATION PONDS*
William Marcus Ingram, W. W. Towne, and
William Bliss Horning II**
The references cited here are pertinent in their relationship to the successful devel-
opment of functional waste stabilization ponds or lagoons which treat domestic sewage in
the United States. Readers of this bibliography should turn to additional references in the
publications cited here for further information; obviously it is not possible to include all
papers which can be related to the treatment of decomposable organic wastes, as domes-
tic sewage, in a bibliography of this nature.
Allen, M. B.
1955. General Features of Algal Growth in Sewage Oxidation Ponds.
Publ. No. 13, Calif. State Water Pollution Control Board, pp. 1-47.
Allum, M. O.
1955. Lagoon Purification Performance in South Dakota. American City,
Vol. 70, No. 3, pp. 128-1Z9.
Anderegg, J. A., Walters, C. F., Hilliard, D. , and Meyers, H. F.
I960. "Eskimo" Algae Make Lagoons Work at the Arctic Circle. Wastes Engi-
neering,
Vol. 31, No. 6, pp. 324-326.
Anon.
1946. Sewage Treatment at Military Installations.
Kept. Sub-committee on Sanitary Engineering, National Research Council,
Div. Medical Sciences, Washington, D. C. ,
Chapter 10 - Oxidation Ponds, pp. 1023-1026.
Anon.
1957.
Anon.
1960.
Sewage Stabilization Ponds in the Dakotas.
Vols. I-II (Joint Rept. , Depts. of Health of North Dakota, South Dakota
and The U. S. Public Health Service)
Printed: Robt. A. Taft Sanitary Engineering Center, Cincinnati, Ohio.
Waste Stabilization Lagoons: Design, Construction, and Operation Prac-
tices Among Missouri Basin States. (Reproduced by Dept. of Health, Edu-
cation, and Welfare, U.S. Public Health Service, Region VI, Water Supply
and Pollution Control Activities, 2200 Federal Office Bldg. , 911 Walnut
Street, Kansas City 6, Mo.)
Committee Report Approved by the Missouri Basin Engineering Health
Council on January 1, I960, pp. 1-12.
"To be associated with paper, " Some Observations on the Growth, Application, and Operation of Raw Sewage Stabilization
Ponds, " (See page 68).
••Biologist, Chief, and Biologist respectively of Field Operations Section, Technical Services Branch, Division of Water Supply
and Pollution Control, Public Health Service, Robert A. Taft Sanitary Engineering Center, Cincinnati, Ohio.
165
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Bartsch, A. F. and Allum, M. O.
1957. Biological Factors in Treatment of Raw Sewage in Artificial Ponds.
Limnology and Oceanography,
Vol. 2, No. 2, pp. 77-84.
Beadle, L. D. and Harmston, F. C.
1958. Mosquitoes in Sewage Stabilization Ponds in the Dakotas.
Mosquito News,
Vol. 18, No. 4, pp. 293-296.
Caldwell, D. H.
1946. Sewage Oxidation Ponds - Performance, Operation, and Design.
Sewage Works Journal,
Vol. 18, No. 3, pp. 433-458.
Davis, W. H.
1955. Sewage Lagoons in the Dakotas.
Off. Bull. N. D. Water and Sewage Wks. Conf. ,
Vol. 23, pp. 5-6.
Ehlers, V. M.
1954. Oxidation Ponds - Their Application and Potentials.
Off. Bull. N. D. Water and Sewage Wks. Conf. ,
Vol. 22, pp. 3-14.
Ellison, R. P. and Smith, R. L.
1954. Evaluating the Use of Sewage Lagoons.
Public Works,
Vol. 85, No. 3, pp. 89 and 142.
Fitzgerald, G. P. and Rohlich, G. A.
1958. An Evaluation of Stabilization Pond Literature.
Sewage and Industrial Wastes,
Vol. 30, No. 10, pp. 1213-1224.
Gidley, H. K.
1956. Treating Septic Tank Effluent by an Oxidation Pond.
Public Works,
Vol. 87, No. 1, pp. 81-82.
Gloyna, E. F. and Hermann, E. R.
1956. Some Design Considerations for Oxidation Ponds.
Proc. American Society of Civil Engineers,
Vol. 82, Paper 1047.
Gloyna, E. F. and Hermann, E. R.
1957. Discussion: (Algae in Waste Treatment by Oswald, Gotaas, Golueke and
Kellen).
Sewage and Industrial Wastes,
Vol. 29, No. 4, pp. 455-457.
Gotaas, H. B., Oswald, W. J. and Ludwig, H. F.
1954. Photo synthetic Reclamation of Organic Wastes.
Scientific Monthly,
Vol. 79, No. 12, pp. 368-378.
166
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Gotaas, H. B. , Oswald, W. J., and Golueke, C. G.
1954. Algal-Bacterial Symbiosis in Sewage Oxidation Ponds - 5th Progress
Report.
Institute of Engineering Research, Univ. of Calif. ,
Bull. Ser. 44, No. 5, pp. 1-88.
Hermann, E. R. and Gloyna, E. F.
1958. Waste Stabilization Ponds - I Experimental Investigations.
Sewage and Industrial Wastes,
Vol. 30, No. 4, pp. 511-538.
Hermann, E. R. , and Gloyna, E. F.
1958. Waste Stabilization Ponds - II Field Practices.
Sewage and Industrial Wastes,
Vol. 30, No. 5, pp. 646-651.
Hermann, E. R. and Gloyna, E. F.
1958. Waste Stabilization Ponds - III Formulation of Design Equations.
Sewage and Industrial Wastes,
Vol. 30, No. 8, pp. 963-975.
Hopkins, G. J.
1956. Raw Sewage Lagoons.
Water and Sewage Works,
Vol. 103, No. 8, pp. 566-570.
Howells, D. H. , and Dubois, D. P.
1959. The Design and Cost of Stabilization Ponds in the Midwest.
Sewage and Industrial Wastes,
Vol. 31, No. 7, pp. 811-818.
Kabler, P. W.
1959. Removal of Pathogenic Microorganisms by Sewage Treatment Processes.
Sewage and Industrial Wastes,
Vol. 31, No. 12, pp. 1373-1382.
Ludwig, H. F. and Oswald, W. J. , et al.
1951. Algae Symbiosis in Oxidation Ponds - I. Growth Characteristics of
Euglena gracilis Cultured in Sewage.
Sewage and Industrial Wastes,
Vol. 23, No. 11, pp. 1337-1355.
Ludwig, H. F. and Oswald, W. J.
1952. Role of Algae in Sewage Oxidation Ponds.
(Symposium on the Role of Ecology in Water Pollution Control), Scientific
Monthly,
Vol. 74, No. 1, pp. 3-5.
Merz, R. C. , Merrell, J. C. , and Stone, R.
1957. Investigation of Primary Lagoon Treatment at Mojave, Calif.
Sewage and Industrial Wastes,
Vol. 29, No. 2, pp. 115-123.
Neel, J. K.
1955. Biological Aspects of Three North Dakota Sewage Lagoons.
Off. Bull. N. D. Water and Sewage Wks. Conf. ,
Vol. 23, pp. 13-15; 22.
167
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Neel, J. K. , and Hopkins, G. J.
1956. Experimental Lagooning of Raw Sewage.
Sewage and Industrial Wastes,
Vol. 28, No. 11, pp. 1326-1356.
O'Connor, D. J., and Eckenfelder, W. W., Jr.
I960. Treatment of Organic Wastes in Aerated Lagoons.
Journal Water Pollution Control Federation,
Vol. 32, No. 4, pp. 365-382.
Oswald, W. J. , Gotaas, H. B., et al.
1953. Algae Symbiosis in Oxidation Ponds - II Growth Characteristics of
Cholorella pyrenoidosa Cultured in Sewage.
Sewage and Industrial Wastes,
Vol. 25, No. 1, pp. 26-37.
Oswald, W. J. , Gotaas, H. B., Ludwig, H. F. , and Lynch, V.
1953. Algae Symbiosis in Oxidation Ponds - III Photosynthetic Oxygenation.
Sewage and Industrial Wastes,
Vol. 25, No. 6, pp. 692-705.
Oswald, W. J. , and Gotaas, H. B.
1955. Photosynthesis in Sewage Treatment.
Proc. Amer. Soc. Civil Engr. ,
Vol. 81, Separate No. 686, pp. 1-27.
Oswald, W. J. , Gotaas, H. B., Golueke, C. G., and Kellen, W. R.
1957. Algae in Waste Treatment.
Sewage and Industrial Wastes,
Vol. 29, No. 4, pp. 437-455.
Parker, C. D. ,- Jones, H. L. , and Taylor, W. S.
1950. Purification of Sewage in Lagoons.
Sewage and Industrial Wastes,
Vol. 22, No. 6, pp. 760-775.
Parker, C. D. , Jones, H. L. , and Greene, N. C.
1959. Performance of Large Sewage Lagoons at Melbourne Australia.
Sewage and Industrial Wastes,
Vol. 31, No. 2, pp. 133-152.
Pearse, L. , et al.
1948. Oxidation Ponds.
Report of the Committee on Sewage Disposal Engineering
Section, Amer. Pub. Health Assoc. ,
Sewage Works Journal,
Vol. 20, No. 6, pp. 1021-1031.
Peterson, N. L.
1955. Sewage Treatment by Lagooning.
Off. Bull. N. D. Water and Sewage Wks. Conf. ,
Vol. 23, pp. 21-22.
Sampson, E. O.
1955. A Double Duty Oxidation Pond.
Sewage and Industrial Wastes,
Vol. 27, No. 12, pp. 1410-1415.
168
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Silva, P. C. and Papenfuss, G. F.
1953. A Systematic Study of Sewage Oxidation Ponds.
Calif. State Water Pollution Control Board,
Publ. No. 7, pp. 1-35.
Smallhorst, D. F. , Walton, B. N. , and Meyers, J.
1953. Design and Operation of Oxidation Ponds.
Public Works,
Vol. 84, No. 12, pp. 89-90; 111-114.
Smallhorst, D. F. , Walton, B. N. , and Meyers, J.
1954. Oxidation Ponds.
Texas Water and Sewage Wks. Assoc. , Manual for Sewage Plant
Operators, (2nd Ed.),
Chapter 13.
Steel, E. W. , and Gloyna, E. F.
1955. Concentration of Radioactivity in Oxidation Ponds.
Sewage and Industrial Wastes,
Vol. 27, No. 8, pp. 941-956.
Towne, W. W.
1957. Sewage Stabilization Ponds for Suburban Housing Developments.
Journal National Home Builders Assoc. ,
August, pp. 85-88.
Towne, W. W. and Davis, W. H.
1957. Sewage Treatment by Raw Sewage Stabilization Ponds.
Journal Sanitary Engineering Division,
Proc. Amer. Soc. Civil Engr. ,
Paper 1337, SA-4: 1337, pp. 1-17.
Towne, W. W. , Bartsch, A. F. , and Davis, W. H.
1957. Raw Sewage Stabilization Ponds in the Dakotas.
Sewage and Industrial Wastes,
Vol. 29, No. 4, pp. 377-396.
Towne, W. W. and Pahren, H. R.
1959. Use of Stabilization Ponds in Treating Sewage and Industrial Wastes.
Proc. 8th Southern Municipal & Ind. Wastes Conf. ,
Chapel Hill, N. C. , April 1959.
Tsivoglou, E. C. , Pecsox, D. A. and Valentine, R. F.
1956. Field Use of Radiotracer in a Sewage Oxidation Pond Flow Study.
Sewage and Industrial Wastes,
Vol. 28, No. 10, pp. 1211-1218.
Van Heuvelen, W.
1952. Sewage Disposal by the Lagoon Method.
Off. Bull. N. D. Water and Sewage Wks. Conf. ,
Vol. 22, No. 4, pp. 24-26.
Van Heuvelen, W. , and Svore, J. H.
1954. Sewage Lagoons in North Dakota.
Sewage and Industrial Wastes,
Vol. 26, No. 6, pp. 771-776.
169
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Wennstrom, M.
1949. Biological Purification of Settled Sewage in Shallow Ponds.
Proc. United National Scientific Conf. on Conservation and Utilization of
Resources, Aug. 17-Sept. 6, 1949,
Lake Success, N. Y. , pp. 124-127.
Wilson, J. N. , McDermott, J. H. , and Livingston, A. , III
I960. Performance of a Sewage Stabilization Pond in a Maritime Climate:
1957-1958.
Proc. 15th Purdue Ind. Wastes Conf. ,
May I960, (In Press).
170
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