United States
Environmental Protection
Agency
Office Of Water
(WH-556)
EPA 842-K-93-001
August 1993
1
The National Environmental
Benefits Of The Clean Water Act
Progress Made In The
United States Through The
Secondary Treatment Of
Municipal Wastewater
Some twenty years since
passage of the Clean Water Act,
a nationwide review shows
promising results for the
environment.
Recycled/Recyclable
Printed on paper that contains
at least 50% recycled fiber
-------
he U.S. Environmental Protection Agency (EPA)
recently completed a review of the national environ-
mental benefits of the Clean Water Act's secondary
treatment requirements. The findings of this review
demonstrate that significant progress has been made
in improving water quality and other environmen-
tal resources through the secondary (and advanced)
treatment of municipal wastewater. The findings
also show that the rapid population growth and
industrial development between the 1950s and the
late 1980s was outpaced by the nation's increased
ability to treat and control wastewater pollution.
During this period, many treatment plants were
required to upgrade to secondary or advanced treat-
ment levels.
An examination of the case studies included in the
EPA review reveals important, visible environmen-
tal benefits at 14 different sites across the nation.
Located in large urban-industrial centers on major
waterways, these sites collectively depict significant
improvements in water quality and related envi-
Trends in Municipal Wastewater Pollutants and
Population Served by Secondary Treatment (1950-88)
STUDY
STUDY
8000
1950
1955
1960
1965
1970
1975
198O
1985
§
•o
g
5
(0
o
1990
Since 1972, more than 60 billion federal dollars, along with significant state and local funds, has been invested in the
nation's wastewater treatment infrastructure. In turn, the nation's ability to treat wastewater kept pace with the rapid ,
expansion in population, which included a significant growth in the population served by wastewater treatment. (The term
BODS refers to biodegradable organic pollutants measured over a five-day period.)
-------
ronmental resources following the passage and
implementation of the Clean Water Act.
commercial fisheries, and other economic gains, as well as
a more beautiful, healthful place to live.
From Oregon's Willamette River to Washington,
D.C.'s Potomac, the environmental benefits realized
by improvements in wastewater treatment have
ranged from the reopening of beaches, parks, and
swimming areas to the enhanced diversity of fish and
wildlife populations. To the delight of local communi-
ties, these improvements have translated into increased
tourism, the resurgence of recreational boating and
It is clear that large gains have been made through
implementing the Clean Water Act's requirement
for secondary treatment of wastewater. Today,
many stretches of the nation's rivers and streams
are once again "fishable and swimmable." Many
more are well on their way to reaching these goals
of the Clean Water Act.
' . Defining Wastewater Treatment
'_ ' ' '"M/V.,,..-, ' ' • '•
1972, ihe JJ.S. Congress enacted far-reaching amendments to the Federal Water Pollution Control Act of 1948.
SThese amendments, along with additional amendments in 1977,1981, and 1987, are now collectively known as the
Zlean Water Act, In addition to setting forth the goal of rendering all U.S. navigable waters "fishable and swim-
pSpable" by 1983, they also mandated that all publicly owned [wastewater] treatment works (POTWs) install pro-
ifccesses to meet a minimum of secondary treatment requirements by 1983 (later delayed to 1988). Wastewater
grtreatment systems are designed and operated in a manner to remove pollutants to specified levels before the water
it- is released into the environment.
Primary treatment
Primary treatment, which removes some suspended solids using physical processes
such as screening and sedimentation, is rarely effective enough to protect the
integrity of the environment when the effluent is discharged to surface waters.
Secondary treatment Secondary treatment removes biodegradable organic materials (BOD) and
suspended solids from wastewater. As BOD in the water decreases, the amount
——- of life-sustaining dissolved oxygen in the water increases. Secondary treatment
~~ also removes significant amounts of heavy metals and toxic organic pollut-
- —— ants—especially those adsorbed onto suspended solids—as well as some
nitrogen and phosphorus.
The Act also required the formation of water-quality standards based on
minimum EPA criteria. If local water-quality standards are not achieved
through secondary treatment, higher treatment levels (and advanced treatment
facilities) are required. Advanced treatment of wastewaters can greatly reduce
> nutrients, heavy metals, and toxic organic chemicals, as well as meetrnpre
stringent limits for BOD and suspended solids.
Advanced treatment
-------
Nationwide Improvements in Water Quality
Before and After the Clean Water Act of 1972
LEGEND
D«setved Oxygen (mgft.)
Dallas-Fort Worth
Upper Trinity River
~o - •
" 1961 1988
Passage of the Clean Water Act has resulted in significant gains in water quality nationwide. That is, as discharges of
oxygen-depleting biodegradable organic wastes have decreased through secondary and, in many cases, advanced
treatment ofwastewater, levels of life-giving dissolved oxygen have increased.
111 in i i ii in ii ii'i mur FIIIHUIIIIIH 11 »i*/irasiiiiBiiBaBfclBS>iiWwsiail»«i««lii?>iW**af«WB'f'4»
"Over the past 20 years, the nation has made considerable progress in controlling and rec
' certain kindsof chemical pollution of its rive lakes, and wetlands... D/recf/nafusfr/a/c/Asc/?arg'es/?a\/e"
; been controlled. As a resu]tt the chemical water quality, including dissolved oxygen".., In many Jakes '
'- and rivers has improved, and loadings of some toxic contaminants have decreased."
l> ": = ^Alan B. Nichols, "It's Clear, U.S. Waters Have Improved," Water Environment and Technology NRC ^
I: "Report, Restoration of Aquatic Ecosystems.
t ' 1- -* -Vr
-------
Nationwide Environmental Benefits
Since Passage of the Clean Water Act of 1972
Case Study Site
Connecticut River
Delaware River
French River
Hudson-Rantan Estuary
James River
Little Calumet River
Occoquan River
Ohio River.
^{Louisville, KY & Cincinnati, OH)
Potomac River
Quinnipiac River
Pacific Ocean
(Encina, CA)*
Trinity River
(Dallas-Fort Worth, TX)**
Upper Chattahoochee River
Environmental Benefits
A Return of Atlantic salmon
A Stability of juvenile shad populations
A Greater number and diversity of fish species (e g , shad, striped bass, shortnose sturgeon)
A Improved overall fishability
A Reduction in nutrient levels
IJI " ' Upper Mississippi River
A
A
Reopening of bathing beaches
Reduction in waterborne diseases
End to seasonal restrictions on many shellfishing beds
Enhanced diversity of fish habitat (e g , striped bass, American shad)
Expansion of overwintering waterfowl (e g , Canadian geese, herons, egrets)
Recovery of fish (e.g., small- and largemouth bass, striper)
Reappearance of many bird species (e.g., pelicans, bald eagles, egrets, herons)
Now site of Bass Masters fishing tournament
Jump in number of recreational vessels and lockages
Recovery of numerous fish populations (e g, bluegill, largemouth bass)
Reduction in nutrient levels
Healthier drinking water supply
Greater diversity of pollution-sensitive fish species
Recovery of sport fishing and tournaments (e g , Bass Anglers)
Return of submerged aquatic vegetation (SAV)
One of nation's top-ranked largemouth bass fisheries
Increase in waterfowl abundance/diversity (e.g., redhead, canvasback duck)
Heightened use of trails for walking, jogging, and cycling
Boating, commercial fishing
Enriched population of bpttom-dwefling species
Growth of pollution-sensitive populations
Revival of boating and other forms of recreation
Improved dissolved oxygen, reduced pollutants and oil and grease
Enhanced diversity of benthic community in Southern California nearshore
Greater diversity of fish species
Return of the flathead catfish, a popular gamefish sensitive to pollution
Recent rises in blue crab, shrimp, and oyster catches in receiving Galveston Bay
End of bloodworm-infested sludge mats
Recovery of sportfish populations
Improved diversity of microinvertebrate fauna
Revival of water-based and contact recreation
A Return of mayflies
A; Development of parks, trails, and marinas
: A More, recreational craft
A Return of birds (e.g , bald eagles, cormorants, night herons)
. A Increase in.minks and other fish-eating mammals
:-.A; Greater number and diversity of fish (e g , blue sucker, paddle fish)
Willamette River A Return of pollution-sensitive organisms
A Healthier salmon population
A Greater interest in angling
A Expansion of commercial fisheries .
This case study, which describes discharges to coastal waters, was conducted separately for EPA by the Association of
Metropolitan Sewerage Agencies.
This case study was conducted separately by the National Oceanic and Atmospheric Administration.
-------
Case Study Highlights
The Potomac River
D
Washington, D.C.
Potomac River
10
5
0
1963 1988
"uring much of the past cen-
tury, the Potomac River has been
characterized by severe water
pollution problems resulting
frompopulationgrowfhinmeWashMgton,D.C.,areaand
from inadequate levels of wastewater treatment. These
problems have included bacterial contamination, fish kills,
and nuisance algal blooms.
Since the early 1980s, submerged aquatic vegetation
(SAV) has made a significant reappearance in the
upper tidal reaches of the Potomac. The loss of this
vegetation had adversely impacted fish and water-
fowl habitats and food resources of both the Potomac
River and the Chesapeake Bay.
The Potomac estuary is now one of the nation's top-
ranked largemouthbass fisheries and supports many
professional fishing guides and Bass Masters Fishing
Tournaments. Freshwater guide services, now larger-
than-ever in the Washington area, have reported that
every year since 1982 has been better than the previ-
ous year for the quantity and quality of fish that have
returned to the waters of the tidal Potomac. The
quality of habitat for fish in the Potomac has increased
with the resurgence of aquatic vegetation, compared
to areas lacking such beds. From 1984 to 1986—years
characterized by a rapid increase of the distribution of
SAV beds—fish surveys near Washington, D.C.,
clearly showed an increase in abundance from 79 to
196 fish per net haul.
Both the numbers and the list of bird species occur-
ring in the estuary have doubled. (Many of these
species consume aquatic vegetation directly or feed on
SAV-eating fish populations.) For example, although
only nine species of ducks wintered on the Potomac in
1972, that number jumped to 17 in 1992. Fall-migrating,
SAV-eating widgeons and gadwalls, absent in the
estuary for 15 winters, have lengthened their stay in the
area, possibly encouraged by recent warmer winters and
more plentiful food supplies. Populations of mergansers
and other fish-eating bird species have also increased
since the 1970s, along with Canadian geese, tundra
swans, and mallards.
As a result of major improvements in water quality
over the past decade, recreational and commercial
fishing, as well as boating, have become important
uses of the Potomac estuary. .In addition, walking,
jogging, and bicycling on trails along the river's banks
in the vicinity of Washington, D.C., are once again
extremely popular.
The Upper Mississippi River
Minneapolis-St. Paul
Upper Mississippi River
1961 1988
ice full implementation of
secondary and advanced waste-
water treatment in the Twin Cit-
ies, achieved by the mid-1980s,
the water quality of the Upper Mississippi River rou-
tinely has been in compliance with water-quality stan-
dards. As a result of the river's cleanup in the Twin Cities
region, mayflies—a prime fish food extremely sensitive
to low oxygen conditions—have returned after a 30-
year absence. Parks, trails, and marinas are now being
developed along river stretches once considered worth-
less. The improved water quality has brought about a
dramatic increase in recreational traffic on the river,
starting around 1986. By 1991, the number of recre-
ational crafts passing through four of the river's locks
had jumped by about two-thirds.
-------
Case Study Highlights
Also partly attributable to the ban of DDT and other
factors, birds are returning to the Upper Mississippi.
Peregrine falcons, bald eagles, mallards, cormorants,
and great blue herons are back in the Minneapolis-
Saint Paul metro area. Black-crowned night herons
now feed below the Ford Dam, while fish-eating
mammals such as the mink are also making a come-
back. Similarly, samples from Spring Lake have
revealed an increase in the diversity and abundance
of certain species, including the paddle fish, which
had not been spotted in some sites for 30 years.
The resurgence of mayflies, the reappearance of
previously vanished bird populations, and the recov-
ery and proliferation of many fish species, as well as
the complete compliance with water-quality stan-
dards, are major indicators of the effectiveness of
water pollution control efforts accomplished in the
Upper Mississippi River. Old Man Paver is no longer
a place to avoid.
The Willamette River
"ecause of raw sewage dis-
charges and inadequate levels of
municipal and industrial waste-
water treatment, the Willamette
was once one of the nation's most outrageously pol-
luted rivers. In the 1950s, gross water pollution condi-
tions resulted in high bacterial levels, oxygen deple-
tion, and fish kills.
Legislation strongly supported by the public has
brought about a major cleanup. In particular, the
requirement of a minimum level of secondary treat-
ment for wastewater-—mandated first by the State of
Oregon and later by the Clean Water Act—has helped
restore the river's ecological balance. Over the past 20
years, average levels of dissolved oxygen in the
Willamette River have increased significantly.
Along with other factors, the improvements, in water
quality have played an important role in the survival
and return of both natural-born and hatchery-reared
salmon in the Willamette River. In 1965, only 79
chinook salmon were counted in the autum run; that
number, however, jumped to 5,000 in 1971. A record-
high abundance of 106,300 spring chinook salmon
were estimated in the 1990 run, up 30 percent from
the 1985-89 average of 81,900. Similarly, the actual 1990
catch, over 27,000, surpassed the 1980-89 average of
20,000 by 39 percent. With the increased growth in the
Portland area (where most of the salmon are caught) and
water-quality improvements, the interest in angling in
the river has reached a new high. The Willamette River is
once again able to support the important commercial and
recreational fisheries of the past.
The Ohio River
Cincinnati
Ohio River
10 -
5 -
0.-
I
1965 1988
I rowing concern for the Ohio
River's environmental condition
peaked in the early 1930s when a
serious drought turned many of
the river's slack-water pools into virtual cesspools, and
a series of epidemics plagued cities along the Ohio. In
1939, the city of Marietta was forced to switch its
water supply from the Ohio River to wells and to
another river because the Ohio's pollution levels had
become untreatable. In 1951, sections of the river were
suffering such severe oxygen depletion that aquatic
life could not survive.
-------
Case Study Highlights
Stringent permit requirements for dischargers as well
as improvements in wastewater treatment facilities in
the late 1960s and 1970s resulted in significant de-
creases in pollutant levels despite population increases.
The consequently improved water quality has widened
the diversify of fish, particularly species most sensitive to
pollution. Just south of Cincinnati, two sample sites
exhibited a 13 percent increase in fish diversity, as well as
an overall increase in the numbers of all fish.
Today the Ohio River supports many uses that had
previously been impaired. Sport fishing has returned,
and an increasing number of fishing tournaments take
place along the river. In fact, the Bass Anglers
Sportsman's Society held the Bass Champs Invita-
tional near Cincinnati in 1982 because of the excellent
bass fishery.
The Upper ;CJ
Atlanta
Chattahoochee River
10
1970 1989
"uring the 1940s, '50s, and
'60s, the first 40 miles of the
Chattahoochee River below
Atlanta were grossly polluted,
particularly because of inadequately treated wastewa-
ter. Water-quality conditions were, not surprisingly,
quite poor. Concentrations of fecal coliform bacteria,
ammonia, biodegradable organic materials, and
suspended solids continued to be high both up- and
downstream from the plant's discharge at Peachtree
Creek. Fish kills caused by discharges of raw sewage and
industrial chemicals were commonplace up until 1976.
Combined efforts of the State of Georgia, local communi-
ties and industries, and EPA construction grants via the
Clean Water Act for municipal wastewater treatment
systems have put the Upper Chattahoochee River on the
road to recovery. Promising improvement signs in the
region's major water supply source and waste re-
ceiver include the following:
A Bloodworm-infested sludge mats no longer float in
the shallows below Atlanta.
A Sportfish populations are recovering.
A Dissolved oxygen is on the rise.
Microinvertebrate fauna is more diverse.
A
A
Fishing is generally supported along the
entire river.
A The river's natural ecological balance is
returning.
Water-based recreational activities are now possible all
along the river, and the Chattahoochee's headwaters are
popular for trout fishing, camping, and hunting. Al-
though heavily developed, the river's reach from Buf ord
Dam to Atlanta supports fishing, canoeing, and rafting,
while the stretch between Morgan Falls and Peachtree
Creek — one of the river's most scenic areas — hosts an
annual raft race that draws thousands of participants and
onlookers. West Point Lake is widely used for fishing,
boating, camping, and swimming.
Additional Information
I Lead EPA Offices to Implement
Secondary Treatment: ~ '
Office.of Wastewater Enforcement and.Cprnpliance
r ) . - ... .. .—.—., «
For more information, please write to:
p m^mmfh^^v ^HW^H^f^m^mmfVfMTts » ' ,, ^ ^ ™
£ Secondary Treatment Benefits Study
LOffice of Wastewater Enforcement and Compliance
401 M Street, SW (WH-546)
^Washington, D C 20460
^ry Treatment Benefits Study
IE Oceans and_ Coastal Protection Division^
P dffice'of Wetfands, Ocean's "and Watersheds"
£ U S. E/wironuiental Protection Agency
p 401 M Street, SW (WH-556F)
" ^Washington, D.C. 20460
r
F Note This publication is adapted from The National Environmental
tfieagfi(§ of Secondary Treatment, U S EPA TechnicaLReport, 1993
------- |