TECHNOLOGY TRANSFER
The Bridge Between Research and Use
May 15
1972
ENVIRONMENTAL PROTECTION AGENCY
WPCF PRESIDENT PARTICIPATES IN
NEW YORK DESIGN SEMINAR
Joseph F. Lagnese, President, Water Pollution
Control Federation, participated in the Tech-
nology Transfer Design Seminar held in New
York City February 29 and March 1-2,1972.
Mr. Lagnese opened the general discussion
session on March 2 with a presentation on the
cooperative efforts of the Federation and the
Technology Transfer Program. He stated
". . . . there is no question that EPA Technology
Transfer, by their special efforts, has achieved a
position of respect and prestige with the Federa-
tion officially and I am sure with most of our
members." Mr. Lagnese further stated: "Possibly
even more significant and encouraging than the
improved rapport between EPA and professional
organizations is that the Federal program, by
example of the Technology Transfer effort.
Joseph F. Lagnese, President, Water Pollution Control Federa-
tion, addressing participants in New York Design Seminar.
demonstrates a more serious consideration to
the essential role of engineering in the achieve-
ment of national water pollution control
objectives."
One of the points discussed by Mr. Lagnese
was that a conflict between the Technology
Transfer Process Design Manuals and the WPCF
Manuals of Practice does not exist as the
respective areas of interest differ. He pointed
out that: 1] whereas the MOP's are limited to
well-established practices of rather long-term
use, the Design Manuals on the other hand relate
to process design in areas where research and
demonstration has been more recent; and 2] the
continued cooperation and coordination
between WPCF and Technology Transfer would
minimize the potential for overlap, redundancy,
and conflict in the future.
The importance of this cooperation between
the Federation and Technology Transfer was the
main theme of Mr. Lagnese's presentation.
".... no other program in EPA or the water
pollution control agencies preceding EPA, to my
recollection, has had a better record in this
regard" he concluded.
ANALYTICAL QUALITY CONTROL
HANDBOOK
linitial distribution
of the Handbook for
Analytical Quality
Control in Water and
Wastewater Labora-
tories will take place at
the 92nd annual meet-
ing of the American
Water Works Associa-
tion to be held in Chi-
cago, Illinois, June 4-9,
1972. The Handbook
can be obtained at no cost at EPA's Technology
Transfer exhibit; it will also be available free of
imfccg
ANALYTICAL
QMTY
CCNTKCi
Nwe
AND
V\ASIRAAER
IAECRATCRIES

-------
charge through the regional Technology Transfer
committees listed in the back of this publi-
cation.
The quality control handbook was prepared
for Technology Transfer by the EPA Analytical
Quality Control Laboratory in Cincinnati, Ohio.
Personnel from both programs will be available
at the AWWA meeting to discuss the handbook
in more detail, as well as the functions of the
AQC Laboratory. Presented below is a summary
of the responsibilities and mission of the AQC
Laboratory.
The AQC Laboratory (Dwight G. Ballinger,
Director) is part of the National Environmental
Research Center in Cincinnati. Its Mission is the
development of physical, biological, and micro-
biological methods for the field and laboratory
analysis of water, wastewater, and sediment
samples. Additional responsibilities include the
evaluation of method reliability and the estab-
lishment of quality control techniques for EPA
laboratories.
The Laboratory has a staff of 54 scientists
and technicians and an in-house budget of more
than $1 million annually. The Laboratory Staff
monitors an additional one-half million dollars
in contracts and grants related to methods
development. Methods research involves im-
provements in automated colorimetric proce-
dures, investigations of the usefulness of specific
ion electrodes, improved methods for pesticides,
and the development of techniques for GC-mass
spectral identifications. Oil identification tech-
niques based upon infrared and gas chromatog-
raphy have also been developed by the Labora-
tory. Additional investigations include improved
methods for heavy metals in water and wastes;
the Laboratory has provided EPA methods for
mercury in water, sediments, and fish, in
response to the current crisis involving that
element.
Biological field and laboratory methods are
also being investigated with particular emphasis
on the selection and evaluation of sampling
devices, the preparation of detailed identifi-
cation guides for micro- and macroorganisms
collected in biological surveys, and procedures
for the determination of biomass as a pollution
indicator. The microbiological staff is engaged in
studies of sample preservation, improved tech-
niques for coliform, fecal coliform, and fecal
strep organisms, and the development of
methods for the identification and enumeration
of enteric pathogens.
In support of the research, a special staff
conducts evaluation of EPA methods to deter-
mine the applicability, precision, and accuracy,
by means of interlaboratory studies. Studies
have been completed or are being conducted for
nutrient parameters, oxygen demand measure-
ments, pesticides in water, heavy metals, and
chlorophyll. Methods evaluation reports are pre-
pared and distributed to EPA laboratories and
other interested groups. The Laboratory also
provides a unique service in the form of standard
reference samples for water quality and waste
analyses. These reference samples, based upon
groupings of analytical parameters, are available
from the Laboratory at no cost and may be used
in the evaluation of individual laboratory tech-
niques, analysts' performance, or in the investi-
gation of new instrumental measurement
systems.
The AQC Laboratory is responsible for the
development of continuous monitoring instru-
ments for use by EPA and other Government
agencies. This development includes new sensor
systems, computer interfacing with water qual-
ity monitoring instruments, improvement in
intake design, and a recent development, the use
of a satellite for data transmission.
Major accomplishments of the AQC Labora-
tory are measured in terms of publications. In
1971, the Laboratory distributed more than
10,000 copies of "Methods for Chemical Analy-
sis of Water and Wastes." A recent publication
of the laboratory is "Methods for Organic
Pesticides in Water and Wastewater." In the
summer of 1972, the Laboratory will publish
"Methods for Collection and Analysis of Bio-
logical Field Samples," which is a cooperative
effort among the principal biologists in EPA. In
addition to publication of methods manuals, the
Laboratory also publishes the quarterly AQC
Newsletter, which goes out to many laboratories
inside and outside the Government and offers a
communication device relating to matters of
quality control and methods development. The
current mailing list for the newsletter numbers
more than 5,000.
Among the more interesting challenges in
methods development are methods for organo-
phosphorus pesticides, the use of NMR for
organic pollutant identifications, instrumenta-
tion for the continuous monitoring of industrial
waste effluents, the development of biometric
procedures, and improvements in the identifi-
cation of oil slicks for enforcement purposes.

-------
SECOND PRINTING OF DESIGN
MANUALS COMPLETED
Technology Transfer has finally received the
second printing of the Process Design Manuals
initially released last October. Those individuals
who have previously requested the manuals
should be receiving them shortly; others inter-
ested in obtaining the manuals may do so by
completing the last page of this fact sheet and
forwarding it to the appropriate Regional Tech-
nology Transfer Committee Chairman. We
express our regrets for the delay involved in
distributing these manuals and our thanks to all
those who have patiently awaited their receipt.
A Seminar was held in New York City during
February 29, March 1 and 2, 1972. The program
included technical sessions on physical-chemical
treatment, nitrogen control, and oxygen aera-
tion. Gerald M. Hansler, Regional Administrator,
Region II, gave the opening welcome to the
120-plus consulting engineers and state regula-
tory personnel in attendance. The oxygen aera-
tion session was introduced into the Technology
Transfer Program at this seminar and was well
received. A highlight of the seminar was a group
tour on March 2 to the Newtown Creek Waste-
water Treatment Plant where oxygen aeration is
being applied to 20 MGD of wastewater.
DESIGN SEMINARS
The Technology Transfer design seminar
program sponsored three seminars since January,
1972, bringing the total number of seminars
conducted since the program was initiated to
twelve. The most recent seminars were presented
in Anaheim, California, January 5 and 6; New
York, New York, February 29, March 1, and 2;
and Anchorage, Alaska, March 28 and 29, 1972.
The Anaheim Seminar included sessions on
physical-chemical treatment, nitrogen control,
and suspended solids removal. Mr. John D.
Park hurst, Vice-President, Water Pollution
Control Federation, discussed the EPA Tech-
nology Transfer Program with regard to the
Federation as part of the opening half-day
session.
Gerald M. Hausler, Regional Administrator,. Region II, EPA,
welcoming the participants in New York.
John D. Parkhurst, Vice President, Water Pollution Control
Federation, discussing the Technology Transfer Program in
Anaheim.
PSA (Pressure Swing Adsorption) Oxygen generating unit for 20
mgd oxygen aeration treatment train at Newtown Creek, N.Y.
treatment plant.

-------
Mr. Joseph F. Lagnese, President, Water Pollu-
tion Control Federation, opened the general
discussion session March 2, 1972 (see article on
first page).
The Anchorage Seminar included sessions on
physical-chemical treatment and cold climate
biological waste treatment. A feature of the cold
climate biological waste treatment session was a
presentation by Mr. Jack Grainge of the Cana-
dian Environmental Protection Service. This
session, as with the oxygen aeration session in
New York, was included for the first time in the
design seminar program.
Feature presentations at the above seminars
were given by Swindell-Dressier Company, Pitts-
burgh, Penna.; Metcalf & Eddy Engineers,
Boston, Mass.; Shimek, Roming, Jacobs, &
Finklea, Dallas, Texas; CH2M/Hill, Corvallis,
Oregon; and EKONO, Seattle, Wash., with assist-
ance from Jesse M. Cohen, Edwin F. Barth,
Sidney A. Hannah, Joseph B. Farrell, and John
M. Smith of the EPA National Environmental
Research Center in Cincinnati, Ohio.
NEW TECHNOLOGY IN USE FOR
INDUSTRIAL POLLUTION CONTROL
Following are several examples of the full-
scale implementation of new or innovative tech-
niques for the control of industrial sources of
pollution. These cases are representatives of
what can be accomplished in the way of
improved industrial pollution control through
the use of presently available technology. More
specific information on these projects can be
obtained from the Technology Transfer Chair-
man in the region where the project is located.
AMERICAN ENKA CORP. "Zinc Precipitation
and Recovery from Viscose Rayon Wastewater."
— Region IV
American Enka, in an EPA Demonstration
Project, has won a Finalist Award from the
Sports Foundation, Inc. The award, given for
achievement in the fight against water pollution,
is for a full-scale system for the precipitation
and recovery of zinc from the waste stream of
their Enka, North Carolina, rayon plant.
In the rayon industry, the zinc originates
from the zinc sulfate component of the acid
spinning bath, and is carried into the waste
stream through yarn washing and filter back-
View of complete wastewater treating faciliti3s at Enka plant,
Enka, North Carol na. The large circular tank in the lower
niddle section represents activated sudge plgnt, ^or treatment
only of comestic wastes. Zinc recovery system handling process
waste water is directly above and slightly to tre left of activated
sludge plant.
washes. Previously used technology added
enough lime to raise the pH to 10.3-11.0, which
resulted in a contaminated sludge of low zinc
assay. However, the American Enka installation
utilizes a new technology in which the waste
stream is neutralized with lime to a pH of 6.0, at
which point zinc just begins to precipitate. The
waste stream is then clarified =nd the clear
solution contracted with a circulating dense
slurry cf zinc hydroxide precipit=te. The pH is
raised to 10.0 with sodium hydroxide. The
resultant dense sludge settles easily and is 5-7%
zinc hydroxide. It is dissolved with acid and
reused.
Two thousand pounds of zinc are recovered
daily at American Enka at a value of 13.5-14.0
cents/lb. This zinc recovery pays for the cost of
the treatment plus a partial amortization of
capita- expenditures. Approximately 50 million
lbs. of zinc sulfate are used annually by the
rayon industry. Since the only rcute for zinc to
leave "he spinning process is via e waste stream,
this amount of zinc has previously been lost to
the environment. EPA Project Officer is
Edmond Lomasney of Region IV.
VOLVO BRASS AND COPPER CO. "Treat-
ment, Recovery and Reuse of Copper Wire Mill
Pickling Wastes" — Region II
The Ken'lworth, New Jersey, copper wire
plant of the Volvo Brass and Cooper Company,

-------
has made an order-of-magnitude reduction in
water usage, eliminated chromium, ammonium
and fluoride ion discharges, eliminate dumpings
of pickling baths, and is recovering copper
normally lost in the waste effluent. This EPA
Demonstration Project is an excellent sample of
how a combination of process improvements can
economically make major reductions in plant
waste loads. Water usage of the pickling system
was reduced from 150gpm to 10gpm by the
use of a chemical rinse solution to neutralize
dragout acid from the pickling bath. The neu-
tralized chemicals from the chemical rinse treat-
ment are then removed by a recycled water
rinse. An electrolytic system has been installed
to remove copper from the main pickling solu-
tion, recovering the copper and regenerating the
pickling solution. The third key step is the
substitution of hydrogen peroxide as the oxi-
dizing agent in the bright pickle solution, elimi-
nating chromate, fluoride, and ammonium ions
as pollutants. The recovery of the copper plus
the elimination of operating problems associated
with the use of dischromate as an oxidizing
agent has resulted in a reduced operating cost,
including amortization of the new installation.
EPA project officer is John Ciancia of the
Edison Water Research Division, Cincinnati
NERC.
AMERICAN OIL CO. "Final Purification of
Aerated Lagoon Effluent by Chemical Coagula-
tion—Mixed Media Filtration — Region III
An EPA Demonstration Project involving the
American Oil Company has been awarded first
place in an Environmental Merits Award Pro-
gram sponsored by Petroleum Engineer maga-
zine. The award is for the installation of a
mixed-media filtration system for the aerated
lagoon effluent at Amoco's Yorktown, Virginia
refinery. The filter consists of a concrete tank
containing layered anthracite coal, silica sand,
and ilemenite. Alum is added to the waste
stream pipeline prior to the filter. 1400 gpm of
waste water is being treated. EPA Project Officer
is Leon Meyers of the Robert S. Kerr Research
Center, Ada, Oklahoma.
TECHNOLOGY TRANSFER PARTICIPATES
IN CITY MANAGERS' MEETINGS
Technology Transfer participated in the
spring meeting of the City Managers' Depart-
ment League of California Cities in Coronado,
California March 9, 1972 and in the Northwest
City Managers' Conference in Glenedon Beach,
Oregon, March 11. At these meetings, Tech-
nology Transfer participated in workshops con-
ducted by Public Technology Inc. aimed at
assisting the cities in identifying their needs.
TECHNOLOGY TRANSFER EXHIBITS
The Technology Transfer display booths are
available for appropriate conferences and meet-
ings on a request basis. Requests should be made
to the Regional Technology Transfer Chairmen
(last page of this fact sheet may be used for this
purpose). The following is a firm schedule of
meetings at which one or more of the exhibits
has been or will be displayed.
April 19-21 — National Pollution Control
Conference & Exposition
Houston, Texas
Exhibit: Upgrading Existing Wastewater
Treatment Plants
May 10-12 — New Jersey Water Pollution
Central Association .Conference
Attauta City, New Jersey
Exhibit: Physical-Chemical Treatment
May 14-19 — American Industrial
Hygiene Conference
San Francisco, California
Exhibit: Phosphorus Removal
June 4-9 — American Water Works
Association
92nd Annual Conference
Chicago, Illinois
Exhibit: Analytical Quality Control
July 24-26 — 2nd Urban
Technology Conference
San Francisco, California
Exhibit: Phosphorus Removal
Upgrading Existing Wastewater
Treatment Plants
Physical-Chemical Treatment
Analytical Quality Control
Sept. 11-14 — International Water
Supply Congress
Rockeffer Center, New York

-------
Exhibit: Treating Wastewater
Oct. 8-13 - Water Pollution Control
Federation
45th Annual Conference
Atlanta, Georgia
Exhibit: (Under Construction at Present)
TECHNOLOGY TRANSFER MATERIAL
AVAILABLE
Listed on the last page of this fact sheet is a
current tabulation of available Technology
Transfer publications, audio/visual material, and
exhibits. By completing this page and forward-
ing it to the appropriate Regional Technology
Transfer Committee Chairman, your request(s)
will be filled.
UPGRADING EXISTING TREATMENT
PLANTS
The effective transfer of new and/or improved
pollution control alternatives is the primary goal
of the Technology Transfer Program, and one of
the highest priorities of the U. S. Environmental
Protection Agency. Incorporation of these tech-
nologies in newly designed or constructed facili-
ties is a major step towards solving the pollution
problems facing the country today. However, a
total solution involves the incorporation of these
technologies in existing pollution control facili-
ties.
In the area of domestic sewage far too many
of the approximately 12,000 existing sewage
treatment plants perform inadequately for one
or more of the following reasons: 1) improper
plant operation; b) inadequate plant design;
c) changes in wastewater flow or characteristics;
and d) changes in treatment requirements. Tech-
nology is available today to effectively upgrade
such facilities to acceptable treatment levels.
Detailed discussion of upgrading alternates is
contained in the Technology Transfer Process
Design Manual for Upgrading Existing Waste-
water Treatment Plants, issued October, 1971,
and available from the Technology Transfer
Program (see last page of this publication). A
discussion of the basic technologies involved in
upgrading existing sewage treatment plants is
presented below.
Since the primary clarifier performance signif-
icantly affects the overall effluent quality of
existing treatment plants, and since clarification
is the most economical way to remove sus-
pended and colloidal pollutants, every effort
should be made to improve the primary clarifi-
cation process before additional facilities are
considered.
The technique of adding chemicals to the
primary clarifier is an effective upgrading proce-
dure for a secondary plant. The chemicals
commonly used in wastewater treatment are the
salts of iron and aluminum lime, and synthetic
organic polyelectrolytes. The iron (ferrous and
ferric) and aluminum salts (sodium aluminate or
alum) react with the alkalinity and soluble
orthophosphate in wastewater to form precipi-
tates of the respective metallic hydroxides or
phosphates. In addition, they destabilize the
colloidal particles that would otherwise remain
in suspension. These precipitates, along with the
destabilized colloids, flocculate and settle
readily in a clarifier.
An example of the effect of polyelectrolyte
addition (used either alone or in combination
with inorganic coagulants) on primary clarifier
performance is that, for several plants, the
average values of suspended solids and BOD
removals were increased from 38 percent and 31
percent to 65 percent and 47 percent, respec-
tively. This indicates that the proper selection
and application of polyelectrolytes and chemi-
cals to raw wastewater can significantly improve
primary clarifier performance.
Alum, iron, or polyelectrolyte addition, either
in the primary or secondary treatment process,
can be used advantageously to improve the
overall performance of the treatment system,
including phosphorus removal. Lime addition
may not be feasible for upgrading activated
sludge secondary clarifiers because of the poten-
tial adverse effect of recirculated lime sludge on
mixed liquor microbial characteristics. Lime
addition to primary clarifiers may be used, if
consideration is given to controlling the pH
within acceptable limits for the subsequent
processes, and to changes in sludge character-
istics and handling requirements. Tube settlers
have been used in primary and secondary clari-
fiers to improve performance as well as to
increase throughput in existing clarifiers. The
results of several studies indicate that the over-
flow rates in primary clarifiers can be increased
to 5,000 gpd/sq. ft. while producing the same
quality effluent as the control unit without the
settlers. Tube settlers enhance the ability to
capture settleable solids at high overflow rates

-------
because the depth of settling has been reduced
to a few inches in the tube. It should be realized
that tube settlers do not improve the efficiency
of primary clarifiers that are already achieving
very high (40-60 percent) removals of suspended
solids. Moreover, tube settlers will neither
remove colloidal solids that remain in suspension
nor induce additional coagulation to effect
added particle removal.
The use of effluent polishing of secondary
effluent is a relatively new idea which is receiv-
ing increasing attention as a practical and eco-
_nomical method of upgrading to obtain in-
creased organic and suspended solids removal
from existing treatment facilities. It appears to
be particularly applicable in those cases (and
there are many) where it is necessary to increase
efficiency by an overall amount of 10 to 20
percent in order to meet water quality
requirements.
Four unit processes should be considered for
effluent polishing: 1) polishing lagoons;
2) microstraining; 3) filtration,, including mixed,
multi-media, and moving-bed filters; and 4) acti-
vated carbon adsorption.
Polishing lagoons offer an opportunity for
increased organic and solids removal at a mini-
mum cost. There are two types of polishing
lagoons which can be used, aerobic and faculta-
tive. Aerobic lagoons are generally subdivided
into two groups: 1) shallow lagoons, with depths
in the range of 2.5 to 4.0 feet; and 2) deep
lagoons, with aeration devices included to insure
maintenance of aerobic conditions. Facultative
lagoons are characterized by two distinct zones-
aerobic and anaerobic. Hydraulic and organic
loadings are such that the dissolved oxygen in
the lower section of the lagoon is depleted but
an aerobic layer is maintained near the surface.
Microstraining has application in effluent
polishing chiefly as a method of removing
additional suspended solids (and their associated
BOD) from wastewater treatment plant
effluents. The microstrainer consists of a rota-
ting drum with a peripheral screen. Influent
wastewater enters the drum internally and passes
radially outward through the screen, with depo-
sition of solids on the inner surface of the drum
screen. At the top of the drum pressure jets
remove the deposited solids. The backwash
water is then collected and returned to the head
of the plant. The screens employed in micro-
strainers have extremely small openings and are
made from a variety of metals and plastics.
Individual manufacturers have specific designs
and sizes for the particular needs of any poten-
tial installation.
One of the advantages of using a microstrainer
is its low head requirement. It is, therefore,
advantageous to transfer secondary effluent,
without pumping, to a tertiary microstraining
installation in order to minimize the shear
forced imparted to the fragile biological floe.
Head loss through the microstraining unit, in-
cluding inlet and outlet structures is about 12 to
18 inches. Across the screen, a 6-inch limit is
usually imposed at peak flows. Head losses in
excess of this value are prevented by bypass
weirs. Head loss build-up is reduced by increas-
ing the rate of drum rotation and by increasing
the pressure and flow of the backwashing jets.
These adjustments can be made manually or
automatically.
Microstrainer installations using 23-micron
fabric exhibited average solids removals ranging
from 57 to 89 percent while the 35-micron
fabric exhibited removals of 55 to 73 percent. In
practice, the coarses 35-micron fabric is gener-
ally used for the removal of coarse solids.
Historically, sand filtration has not been an
efficient method of polishing secondary treat-
ment plant effluent because of low application
rates, high head losses, and the need for frequent
backwashing. This is largely because the normal
backwashing of a sand filter results in a size-
graded filter with the finest grains in the upper
layers. The resulting stratification removes the
bulk of the suspended matter in the upper levels,
with a consequent inefficient use of the remain-
ing depth of the filter.
However, developments in mixed, multi-
media, and deep-bed coarse-media filters have
necessitated a re-evaluation of the role of filtra-
tion in effluent polishing. In general, these
modifications permit deeper penetration of the
media by the suspended and colloidal contain-
ments; thus, there is a more effective utilization
of the filer depth as compared to conventional
sand filters. The increased utilization of filter
depth is somewhat offset by the fact that
increased backwashing rates and larger quantities
of washwater are required to backwash the
media properly.
In addition to coarse, mixed, and multi-media
filters, a new filtering technique known as a
moving-bed filter (MBF) has been developed.
The unit is basically a sand filter, but as the
filter surface becomes clogged, the filtering

-------
medium is moved forward by means of a
hydraulically-actuated mechanical diaphragm.
The clogged filter surface is removed mechani-
cally or by gravity, to the extent that a fresh and
clean filtering surface is exposed to the incoming
chemically treated liquid. The unit is thus a
form of countercurrent extraction device which
has the capability of functioning on a contin-
uous basis and does not have to be taken off
stream for cleaning or backwashing.
The limitations of conventional biological
treatment processes in regard to reliable achieve-
ment of a high degree of organic removal
(particularly of certain compounds which are
refractory to biodegradation), along with in-
creasingly strict water quality standards, empha-
size the need for a supplementary organic
removal process. Thus, activated carbon is
presently being used to provide tertiary treat-
ment of biologically treated effluents.
Locations where activated carbon has been
used successfully to provide tertiary treatment
include: Lake Tahoe, Pomona, and Nassau
County. Application at these places clearly
indicates the ability of activated carbon to
produce effluents with very low levels of
organics. At Lake Tahoe, the secondary effluent
is treated with lime followed by clarification and
mixed-media filtration prior to treatment with
the activated carbon; at Pomona, secondary
effluent is treated directly in activated carbon
columns; in Nassau County, secondary effluent
is alum-clarified prior to treatment in activated
carbon columns.
There are at least four methods available for
the post-aeration of a wastewater treatment
plant's effluent. These are: 1) diffused aeration;
2) mechanical aeration; 3) cascade aeration; and
4) U-tube aeration. Most of these devices were
initially developed for water treatment and are
now being used in the wastewater treatment
field.
Of all the types of post-aeration methods, it is
likely that mechanical aeration and U-tube
aeration will find extensive application in the
future. Mechanical aerators are generally
grouped in two broad categories: turbine types
and pump types. In all types, oxygen transfer
occurs through a vortexing action and/or from
the interfacial exposure of large volumes of
liquid sprayed over the surface. To avoid inter-
ference between units, aerator manufacturers
recommend a minimum basin size of 15 to 50
feet square and a minimum depth of 5 to 8 feet,
depending on the horsepower of the aerator.
The U-tube aerator consists of two basic
components: a conduit to provide a vertical
U-shaped flow path and a device for entraining
air into the stream flow in the down leg of the
conduit. The entrainment device is one of two
types: 1) aspirator; or 2) compressor and dif-
fuser. In either case, the entrained air is carried
along the down leg of the tube because the
water velocity exceeds the buoyant rising veloc-
ity of the air bubbles. Various design considera-
tions include air-to-water ratio, tube cross-
sectional area, and depth. The maximum
air-to-water ratio practicable is a function of the
velocity through the system. At velocities of
approximately 4 fps, 20 percent air-to-water
injection requirements for plants of 5 mgd or
less should be less than 5 feet. If sufficient head
is not available, the flow may be pumped
through the U-tube.

-------
WHERE TO GET FURTHER INFORMATION
In order to get details on items appearing in this publication, or any other aspects of the Technology
Transfer Program, contact your appropriate EPA Regional Technology Transfer Committee Chairman
from the list below:
REGION	CHAIRMAN	ADDRESS
I	Lester Sutton	Environmental Protection Agency
John F. Kennedy Federal
Building, Rm. 2304
Boston, Massachusetts 02203
617-223-7210
(Maine, N.H., Vt., Mass.,
R.I., Conn.)
II	Rocco Ricci	Environmental Protection Agency
26 Federal Plaza
New York, New York 10017
201-548-3441
(N.Y., N.J., P.R., V.I.)
Environmental Protection Agency
6th & Walnut
Philadelphia, Pa. 19106
215-597-9410
(Pa., W. Va„ Md., Del.,D.C., Va.)
Environmental Protection Agency
Suite 300
1421 Peachtree St., N.W.
Atlanta, Georgia 30309
404-526-5784
(N.C., S.C., Ky„ Tenn., Ga.,
Ala., Miss., Fla.)
V	Clifford Risely	Environmental Protection Agency
1 N. Wacker Drive
Chicago, Illinois 60606
312-353-5756
(Mich., Wis., Minn., III., Ind.,
Ohio)
VI	George Putnicki	Environmental Protection Agency
1600 Patterson Street
Suite 1100
Dallas, Texas 75201
214-749-3842
(Texas, Okla., Ark., La., N. Mex.)
Warren L. Carter
IV	Asa B. Foster, Jr.

-------
REGION
VII
VIII
IX
X
CHAIRMAN
Lynn Harrington
Stan Smith
Irving Terzich
John E. Osborn
ADDRESS
Environmental Protection Agency
1735 Baltimore Avenue
Kansas City, Missouri 64108
816-374-2725
(Kansas, Nebr., Iowa, Mo.)
Environmental Protection Agency
1860 Lincoln Street
Suite 900
303-837-3961
(Colo., Mont., Wyo., Utah,
N.D., S.D.)
Environmental Protection Agency
100 California Street
San Francisco, Calif. 94111
415-556-7554
(Calif., Nev., Ariz., Hawaii)
Environmental Protection Agency
1200 6th Avenue
Seattle, Washington 98101
206-442-1266
(Wash., Ore., Idaho, Alaska)

-------
REQUEST FOR TECHNOLOGY TRANSFER MATERIAL
Please send me the following publications at no charge and add my name to your mailing list for future
Technology Transfer publications. (Check appropriate boxes)
PROCESS DESIGN MANUALS
~	Phosphorus Removal
~	Carbon Adsorption
~	Suspended Solids Removal
~	Upgrading Existing Wastewater
Treatment Plants
BROCHURES
~	Physical-Chemical Treatment
~	Phosphorus Removal
~	Upgrading Existing Wastewater
Treatment Plants
~	Seattle, Washington METRO
~	Wastewater Purification at Lake Tahoe
~	Indian Creek Reservoir
HANDBOOK
~ Analytical Quality Control in Water
and Wastewater Laboratories
Please contact me regarding the loan of the following audio/visual material. (Check appropriate boxes)
MOTION PICTURES (16mm sound)
~	Richardson, Texas, Project — Title
"Somebody around here must be
doing something good." (15 Min.)
~	Phosphorus Removal (5 Min.)
VIDEOTAPE
~ Carbon Adsorption (40 Min.)
Please forward information on the availability of the following Technology Transfer exhibits. (Check
appropriate boxes)
EXHIBITS
~	Technology Transfer
~	Phosphorus Removal
~	Physical-Chemical Treatment
~	Upgrading Existing Wastewater
Treatment Plants
~	Analytical Quality Control
Name.
Street
City	
State
Zip.
~ U. s. GOVERNMENT PRINTING OFFICE : 1 972 —721-396 (662 )

-------
ENVIRONMENTAL PROTECTION AGENCY
OFFICIAL BUSINESS
PENALTY FOR PRIVATE USE. $300

-------