WSP09153

• File Number: 8041
• Description: Section D General Studies-NPDES/Water Quality
• Date: 7/10/1958
• Title: Water Quality Studies-Pollution-Where We Stand on Pollution Control
• Water Supply Pro - Doc Type: Publication

Newly compiled 1957 figures show cities are selting a good pace in

!".~:r~Yi~g the se;~r~('~"''/''','''~ ~~;,r/I~~~ 1945 '~'1~4'~?'

Number of sewered communities 8,516 8,917
Census population (millions) 75.7 82.0
Estimated population connected (millions) 70.5 74.7 78.9'
Percent of census population connected 93,1 91.1

. . . Reducing raw discharge:
. Number of communities
Estimated population served (millions)

3,597
29.9.

3,610.
27.9

. . . Constructing treatment pl,ants:
. Number of communities
Estimated population served (million,)
Percent of total sewered population

,5,085
40.6
57.6

5,480
46.9
62.7

3,7.18
28.1

..^. -'"- ...;. ~

r.~-'

50.8
644

1953"
9,118
100.3
83.4
83,0

1957
11,131
102.0
984
96.4

3,165
21.9

1
I
I
I
,

I
I

28.2

6,816
55.2
66.2

8,066
764
77.7

. "~faTro'm~R1nYentory-of-Sl!!waQe-Oi'SpO!iQt-Focili~ies.-;Oet;- 15,-.1.9~~-_ p.:-~7- .

Where We Stand on Pollution Control

There's encouraging news in the lat.
est and most complete inventory of
municipal sewage treatment facilities
in the U.S.. just compiled bv the U. S.
Public Health Service. The puhlished
SUn1man" will soon be available from
PHS. .
Population sen ed by treatment
plants increased 38%.. from 5;.2 to
76.4 million between 1953.1957. That's
il big imprm'ement O\"f:r the 8% gtlins
between 19~9.1953 and 19~5-19~9.
The 98.4 million persons served by
sewers represent 57% of the U. S. pop-
ulation.
The encouraging trend continues
when you break down 'the type of treat-
ment.
Population served by secondary,
or complete, treatment increased 66%,
from 26.1 to ~3.3 million, he tween
19~9 ond 1957. Primary and intermedi.
ate plants increased 5-0% in popula"
tion sen'ed during this period.

. The best ever-The new summarv for
1957 is the third published by' the
Public Heolth Sen'ice. And it's the
most complete eyer. It breaks do\\'n
\'~rjous treatment processes by popula-
tIOn sen"ed. as well as bv number of
plants using them. Popubtion figures
giye a truer indication of the extent
to which each type of treatment plant
i.; l1sed.
!here me also breakdowns by popu.
lahon groups and major drainage basins,
in addition to state b\' state rundowns.
Use of high.speed' doto processing
equipment made these additions pos-
sihle.

Earlier PHS inventories ""cre pub-
lished in 1940 ond 1945. ENGINEERING
NEWS.RECORD filled in the gaps by
conducting and publishing similar sur.
veys in 19~6 (ENR Nov. 14, p. 11 2)
and 1953 (ENR Oct 15, p. 37).

. Urban progress-In terms of sewer
SYstems, the 1957 data show that new
U'rban population is being connected to
sewers as it de\'elops and that some
headway has been made in reducing
pre\'iously unconnected population in
urban areas. In 19~5 only 91 % of the
census population of sewe-red communi-
ties \\-'as connected, while todav over
96% is connected. This trend -also is
borne out by .comparing the seweretl
population increase since 1945 (32 %)
with the increase in census population
of sewered communities (25%).
Another significant trend is the in-
crease in population served by treat-
ment facilities of centralized sanitaT\'
districts or other communities. NO\v
20 million persons arc sen'ed, an in-
crease of 65% since 19". It can be
;]rgued that this is a gratifying devel-
opment, since the larger plants associ-
ated with central 5aniblrv districts are
normally better operated and better
designed.
The trend toward separate sewer sys-
tems continues. Now 82% of the 10.-
500 communities reporting is ~erved by
separate sanitary sewers. There was a
decrease in the number of cOJllmuni-
ties reporting combined sewers between
19~5 and 1957.
I n primary treatment plants. the in.
crease in mechanically cleaned settling

tanks was substantial. This type t~nk
now serves 73% of the populal1on
served by primary plants, compared to
56% in 1945. In actual population
served, the mechanical tank has jumped
95% since 1945.

. Disturbing note-The one disquieting
point-and a consequential one-in the
new im'entorv is this: E\'en with the
tremendous \ olumc of treatment plant
construction thc~e days. there probabl~
lias been a slight increase of pollution
loading from community systems dis.
charging into the nation's streams.
True, there has been gratifying decrease
in population discharging ra\\' sewage;
but the reduction of pollutant materials
achiC\'ed by treatment plants has not
heen enough to offset the tremendom
increase in population scn'cd.
This point, and all the other con.
clusions abm'e, arc amplified in tableJ
Jnd analyses on the following pages.
The complete summary of the 195i
inyentor\' (PHS Publication 609) is to
be publi"shed this summer and can be
obt.lined by writing: \Vater Supply and
\Vater Pollution Program, Department
of Hcolth, Education & Welfore. 'Vash.
ington 25, D. C. .
This publie:!.tion includes huge sum-
m<uv tables in which each of the head-
ings" shown on the following pnges, plus
Illan~' others. is brokcn by slate. popu-
lation .e;roup and drainage b..lsin. It has
been onthored bl' John R. Thoman
senior sanitary engineer. and Kenneth
H. Jenlins. anal\'tical statistician. of
USPHS.