SU-734
REFUSE
REPORT
Sum
Latest
in Solid
of the
International
City
Management
Association
Vol. 4 No. 2
April/May/ June 1978
MODULAR INCINERATION UNITS: HOT NEW
DISPOSAL EQUIPMENT FOR LOCAL GOVERNMENTS
Modular incineration units have, in the last
year, become one of the hottest "new" items
of municipal solid waste management. How-
ever, the units are really not that new. They
have been in use by institutions and industries
for many years and a small number have been
in municipal operation for the last six years.
What is "new", is the attention these units are
receiving from local officials. Previously the
units were not given serious consideration
when drawing up disposal alternatives: they
cost too much or there was a lack of available
information.
The implementation of regulations in the
Resource Conservation and Recovery Act
covering municipal solid waste disposal are
having a profound impact on the disposal
methods available to and in use by local gov-
ernments. Some methods can no longer be
used at all (like open dumps) and others which
were not considered in the past will now have
to be (like liners, shredders and modular in-
cinerators). As might be expected, the less ex-
pensive methods (dumps) are giving way to
those that are relatively more expensive (sani-
tary landfilling and processing). Thus, the
costs of modular incineration units are now
within the range of other disposal alternatives
and they should be considered along with
these alternatives.
The information available on these units is still
sparse. However, as more communities invest
in them and request for information, more in-
formation and data will be collected and avail-
able. EPA has a study underway on the sys-
tems in operation, but it will not be available
for another year. Consultants and research
firms are also beginning to collect information
on the units.
Modular incinerators are small, self-contained
(hence the term modular) units. The largest
single one has a 25-ton per day burn capacity.
The smallest has 4.8 tons per day burn capac-
ity. They almost always are sold in pairs. The
chief reason for this is the flexibility it gives to
the solid waste operation. In some communi-
ties where there are seasonal variations in
population, only one unit might be needed dur-
ing the low period of the year, with two units
required during the peak period. Having two
units also provides an immediate backup if one
unit is down for maintenance or repairs or
breaks down during daily operation.
Unlike the incinerators of the past, these units
are not accompanied by large processing sys-
tems or many moving mechanical parts. Mod-
ular units do not have automatic and continu-
ous feed or ash removal and many have no
grates. Also unlike the huge incinerators of the
past, the emissions from the units will usually
meet air quality standards (discussed in more
detail further on).
As might be expected with smaller, less com-
plicated units, there is less waste, labor, capi-
tal, and fuel needed to operate a modular sys-
tem. However, these needs are relative not
only to the number of units used, but also to
the size of the town served. Hence, the city of
North Little Rock, Arkansas population
62,500 (Solid Waste Management, March
1978) is using four 25-ton units while the town
of Meredith, New Hampshire winter popu-
lation 5,000; summer population 20,000 is
using only two 12-ton units. The cost to North
Little Rock was $1.5 million while in Mere-
dith the cost was $225,000.
The staffs of the Innovation Report series and
Refuse Report felt that information was needed
now by local officials to guide them in their
analysis and evaluation of these units. We
have, thus, combined these otherwise separate
reports into one issue. It is our hope that by
doing so we have at least given you, the local
administrator, a starting place when looking
into these units, and in deciding among dis-
posal alternatives. We would very much like
to receive your comments, both on the content
of these reports and on the combined publish-
ing of ICMA reports.
How They Work
Modular incinerators are one complete unit,
thus the entire feed and burn process is con-
tained within this one piece of equipment. In
general there are four main parts of a modular
unit: a receiving compartment; burn chamber,
second bum area; and stack. The process be-
gins when the waste is fed into the receiving
compartment. Once full, the operator pushes a
button on a control panel which is part of the
equipment. This activates a ram which pushes
the waste into the primary Burn chamber. Be-
fore entering the chamber, a fire door is au-
tomatically lifted. This door comes down once
the feed ram is pulled back from the burn
chamber area. The burn area is a pyrolytic
chamber which burns the waste in the near
absence of oxygen. This burning creates a gas
which is then burned again. The second burn
usually takes place above the primary burn
chamber though in older modular units this is
not always so. In newer units the second burn
takes place in the stack.
Reprinted with permission of ICMA by U.S. EPA
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If the gas is to be harnessed for use as an
energy hot water, hot air, or steam it is
tunneled into a recovery mechanism after the
second bum. When the gas is not going to be
used in an energy recovery process, it is sent
into the air after the second burn.
Older modular incineration units have had
some problems with meeting air emission
standards required under federal and state
laws. The problem appears to be with the
temperatures at which the gas is burned. If the
gas is not burned at temperatures in excess of
1300° for a marked period of time, some par-
ticulates will remain and leave through the
stack. This high timed burn is easier to main-
tain in the newer units than in the old; how-
ever, even the new units (purchased in 1976 or
later) can fall below this required burn. When
this happens, the unit will probably not be
meeting many of the more rigorous air stan-
dards.
The daily operation of a unit will consist of
start-up, charge and burn, cool-down, and ash
removal. Start-up is done as rapidly as pos-
sible to conserve fuel and reach the required
temperatures quickly. The unit is then charged
and burned continuously during the operating
day. The units are batch-fed. This is one rea-
son why the units are bought in pairs. While
one unit is being fed, the other can burn. This
makes for a continuous operation of shifts be-
tween the two units.
These units are designed to burn a given
amount of waste for a given time period (for
example in a 16-hour period a given unit will
process 12.8 tons of waste). The units will
take in more waste per charge (or feed into the
burn chamber) than will be burned. Thus,
there is a cool-down period after the final
charge. This cool-down period is averaged at
three hours. During this period, fuel is used to
burn the waste which has not been consumed
during the day. After this waste is burned the
fuel is shut off and the ashes cool. Usually the
ashes are left to cool for the remaining time
until the next operating start-up.
Ash removal is carried out after the unit has
cooled down for a period. Ash removal in the
older units is carried out by a special fork rake
attached to a forklift. In the newer units ash
removal is accomplished automatically by a
ram within the unit.
Uses and Users
Modular incinerators are most commonly used
by smaller communities cities and towns
with populations below 50.000. While many
of the units are used strictly for burning of all
the municipal waste, a good number are used
in conjunction with a recycling and/or energy
recovery program.
All three ol the systems in operation in Arkan-
sas (North Little Rock, Siloam Springs, and
Blytheville) have an energy recovery program
with the incinerators. North Little Rock and
Siloam Springs supply steam to nearby indus-
tries. North Little Rock expects to recover all
costs involved in the construction and opera-
tion of the system as well as receive a profit
from the steam sales.
In New Hampshire, where there are a number
of modular units in use, it is most common to
find a recycling program being run in conjunc-
tion with the incineration system. Most of
these programs begin with voluntary sepa-
ration of glass, newspapers and corrugated
cardboard. Usually the program will after
people have gotten used to it be made man-
datory. The major reasons many communities
have opted for recycling are: it reduces the
final residue amount to be landfilled; it is not
as difficult nor as expensive to begin as an
energy recovery program; and it brings in
revenues to help offset the cost of the incinera-
tors. Systems of recycling with incineration
are in the following communities, with vary-
ing degrees of success: Meredith, New Hamp-
shire; Plymouth, New Hampshire; and Hamp-
ton Falls, New Hampshire.
Costs
Modular incineration units are becoming more
cost-effective as the costs of other disposal al
tematives rise. In areas where land is expen-
sive, these units compare very favorably wit!
other processes such as baling and shredding
Because modular incineration of waste re-
duces the waste by 90 percent in volume, thei
is less landfill area needed than under the oth<
disposal methods. However, incinerators an
by no means cheap and do amount to a sub
stantial investment for any community.
The cost to Plymouth, New Hampshire for
their recycling/incineration system was:
Resource Recovery Seminar
The Environmental Protection Agency's Re-
source Recovery Division (RRD) has been
holding a Resource Recovery Technology
Seminar in various parts of the country since
April of last year. The most recent presenta-
tion of the seminar was in Hartford, Connecti-
cut. The next location is Dearborn, Michigan,
August 29 and 30, 1978.
The two-day seminar has a dual purpose: to
bring local officials up-to-date on resource
recovery/recycling activities in the U.S. and
Europe; and to introduce and educate local
officials on the process of implementing a re-
source recovery system. The seminar also
makes it possible for local officials to meet
with individual staff members of the Division
thus helping to reduce the 'faceless' nature of
federal-local relationships at least in this area.
Presented below are some of the agenda topics
of the Hartford meeting. With the exception of
one session, this same agenda is used for all
the seminars. In an effort to make the meetings
relevant to the particular status of resource re-
covery implementation in a given area, the
luncheon speakers and one or more sessions
are replaced with local speakers. Hence, in
Hartford the luncheon speaker was Mr. Rus-
sell L. Brenneman, President, the Connecticut
Resource Recovery Authority (CRRA) and
one session time was given to the Vice-
President of the CRRA for a presentation on
"'The Life of Resoirce Recovery Project."
Agenda: Implementation Process, Markets,
Source Separation, Economic Consider-
ations, Direct Combustion, Refuse-Derived
Fuel, Pyrolysis, Co-Disposal, Health, Safety
and Environmental Considerations, Contracts,
Risks and Financing.
To enhance the take-home quality of the sen
nar, EPA materials are given to each parti
pant. These include a conference Implemer,
tion Seminar Workbook, the eight part ser
of Resource Recovery Plant Implementatit
Guides for Municipal Officials, and bookl
on source separation programs. These ma
terials are very useful reference and assis-
tance guides when embarking on a resour
recovery/recycling program. The material
are also available from EPA at no cost.
This seminar can be very beneficial to mat
ers and administrators interested in any as
of resource recovery or recycling. For fui
information on future seminars contact: ]
Judy Watt, EPA Resource Recovery Ser
nars, Dulles International Airport, P.O.
17413, Washington, D.C. 20041.
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Construction $138,000
Site Preparation and
Engineering 35,000
Scale 9,000
Baler 6,000
Can Crusher 4,500
Forklift Loader 8,500
Incinerator 95,000
$296,000
Source: Crowley, Robert J , "The Plymouth
Story: An Experience in Solid Waste Man-
agement. '' New Hampshire Town and City,
May 1977.
The 1976 net annual operating costs were
$24,208 for this system. Plymouth has a popu-
lation of approximately 6,400.
The Siloam Springs system which went into
operation in 1974 had the following capital
costs:
Plant Building, Road, and Fence
with Utilities $118,000
Incinerators (2) 146,000
Energy Recovery Units (2) ... 107,000
$371,000
This system has a design capacity of 21 tons
per 10-hour day. The cost per ton of design
capacity is $17,667. In 1975-76, when the
study of this system was done, it was produc-
ing a total of 47,425 pounds of steam per
operating day. In this system, the steam is
used to supplement the primary fuel (natural
gas). In this time period, the use of the steam
and natural gas resulted in a $61.43 savings
per day over the previous all natural gas costs.
The city has a long-term lease with the indus-
try which purchases the steam. This is very
helpful in operations such as this.
Financing for modular incineration units is ac-
complished through the usual channels local
governments use in capital investments
bonds, loans, and private lease-purchase
agreements.
Conclusion
Cautions and Pluses
Modular incineration appears to be a sound
means for small communities to dispose of
their solid waste. When used in conjunction
with either recycling or energy recovery, it
opens up markets and further waste reductions
to these communities. But there are cautions
which must be carefully considered before a
community invests in such a system
Cautions
Air quality. New studies are underway by
EPA and others to test the air emissions of
various systems in operation. Though the
tests are still going on, there appears to be a
concern by many that the results will not be
favorable.
The systems use number 2 oil or natural gas
as fuels. Some systems are very fuel-
inefficient, though most are not. However,
both of these fuels are becoming more ex-
pensive and, in the case of natural gas, al-
most unattainable in some areas.
There is a problem with glass and tires
being burned in some systems. This is ex-
plained in more detail in the Municipal
Innovations Report. The glass can create
In Brief
Recycling and markets ... were up and
down last year. More communities began
programs and found innovative ways to do so
than in previous years while the markets for ,
everything except newsprint and aluminum
cans were down. The two national associa-
tions representing recycling industries both re-
ported a low year for the major recycling items
scrap copper, aluminum and iron and steel.
Aluminum cans and newsprint make up a
small portion of the total market but did very
well. Especially newsprint which went for $30
to $100 per ton depending on the area.
Newsprint's use as insulation was the major
factor contributing to the high price...
The newsprint program in Ontario,
California is recycling 25 to 30 tons of news-
print monthly through a firm fixed price con-
tract of $28 per ton with the Garden State Pa-
per Company. Housewives and students using
city-owned three-wheeled vehicles pick up the
bundled newsprint on regular collection days
...' And despite the overall low in the steel
market, Baltimore County, Maryland recov-
ered 184 million steel cans in 1977 at the
county's municipal solid waste resource re-
covery facility.
Ames, Alcoa and the 'Airknife' ... The
Ames resource Recovery Plant will test an air
knife developed by Alcoa to increase the re-
covery amount of aluminum and other non-
ferrous metals. The knife shoots high velocity
air on a continuous stream of the metals which
separates them into: light e.g., cans;
heavier e.g., license plates; and heaviest
e.g., castings.
huge rocks of melted glass and material in
the primary chamber.
There are differences between systems built
in 1975 and before and those built after.
There is also a big difference between the
various manufacturers. Great caution is
urged in this regard, as some communities
have already been "stuck" with very poor
equipment and very high costs.
Markets can be a problem and should be
dealt with from the very beginning of the
project design. In addition to the usual mar-
ket problems encountered with recovery
projects of any size, there is a materials
storage problem unique to the smaller pro-
grams. It is usually not cost effective to
transport small quantities of materials fre-
quently to the market. Thus, there must be
ample storage space for the collection of
materials between trips to the buyer.
Modular incineration units should be ap-
proached in the same manner as are large
recovery systems. Thus, communities
should have waste data, growth projections,
and other information before going into
such a system. Whenever possible, com-
munities should have complete feasibility
studies performed. This is mentioned be-
cause some communities have not looked
on these systems as they would a large sys-
tem and have suffered financially and polit-
ically as a result.
Pluses
Modular incinerators reduce the volume of
waste to be disposed of by 90 percent.
When accompanied by recycling this means
even greater ultimate reduction.
The systems are flexible and thus can ac-
commodate variations in population and
growth in city size.
The systems can be used to stimulate indus-
trial growth as was done in North Little
Rock through placement in an industrial
area or adjacent to an industry in a park.
This can be of real economic benefit to an
area looking into ways to develop a better
economic base.
Evaluation of Small Modular Incinerators in Munic-
ipal Plants, prepared by Ross Hofmann, Associates
is the main source for data and technical information
contained in this report. The report is available from
the National Technical Information Service, U.S.
Department of Commerce, Springfield, Va. 22161.
Order No. PB-251 291, cost: $6.50.
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Editor's Note
This is the third year we have been publishing
Refuse Report as part of our EPA grant. Since
we first began the newsletter much has
changed in the field of solid waste and in the
needs of local government administrators re-
garding municipal solid waste systems. This
issue represents one effort to be more creative
in our response to your changing solid waste
information needs. I, personally, am very
excited about this joint venture. However,
what you think is what really counts, so please
let us know.
The ICMA Solid Waste Project has been fully
funded by the Environmental Protection
Agency's Office of Solid Waste Management
since 1974. The project offers assistance to
local government managers and administrators
through this newsletter, an extensive inquiry
service, and an on-site peer professional assis-
tance program. If you would like more in-
formation on any of these activities or need
assistance in any area of solid waste manage-
ment, contact us.
Refuse Report is published quarterly hy the
International City Management Association
(ICMA), 1140 Connecticut Avenue, N.W.,
Washington, D.C. 20036, under a grant from the
Environmental Protection Agency's Office of
Solid Waste Management Programs.
Editor:
Assistant Editor:
Production:
Christine H. Hart
Mary Scanlan
Ruth Gregory
WORTH READING
For those interested in the collection, pro-
cessing, resource recovery and disposal of
solid wastes there are a number of monthly
publications which may be of interest. They
are as follows:
Solid Waste Report, published bi-weekly by
Business Publishers, Inc., P.O. Box 1067,
Blair Station, Silver Spring, Maryland
20910: Russell A. Dawson, Editor. Sub-
scription rate $90 per year.
Solid Wastes Management, published
monthly by Communication Channels, Inc.,
6285 Barfield Rd., Atlanta, Georgia 30328.
Al'n Novak, Editor. Subscription rate $12
per year.
Waste Age, published monthly by Three
Sons Publishing Company, 6311 Gross Pt.
Rd., Niles, Illinois 60648. Michael A.
Oberman, Editor. Subscription rate $12 per
year.
Solid Waste Systems, published bi-monthly
by Systems Publishing, Inc., 17071 Ven-
tura Blvd., P.O. Box 588, Enciho, Cali-
fornia 91316. Ben Warner, Jr., Editor.
Subscription rate $9 per year.
Resource Recovery and Energy Review,
published bi-monthly by Wakeman-
Walworth, Inc., P.O. Box 1144, Darien,
Connecticut 06820. S. Keyes Wai worth,
Editor. Subscription rate $9 for six consecu-
tive issues.
CONFERENCE CALENDAR
July 31-August 4: Resource Recovery from Municipal
Solid Waste, Ann Arbor, Mich.
Contact: University of Michigan, College of Engineer-
ing, Continuing Engineering Education, 300 Chrysler
Center, North Campus, Ann Arbor, Mich. 48109,
(313) 764-8490.
August 24-27: NARI Western Division Meeting, San
Diego, Calif.
Contact: National Association of Recycling Indus-
tries, Inc., 330 Madison Ave., New York, NY 10017,
(212) 867-7330.
September 10-13: First Annual Conference of Applied
Research and Practice on Municipal and Industrial
Waste, Madison, Wl.
Contact: Conference Committee, Box 5571, Madi-
son, Wl 53705.
September 15-20: American Public Works Association
International Congress, Portland, Oregon.
Contact: Robert D. Bugher, executive director,
APWA, 1313 E. 60th St., Chicago, IL 60637.
October 14-19: APWA International Congress, Boston.
Institute for Solid Wastes technical sessions in-
cluded.
Contact: Robert D. Bugher, executive director,
APWA, 1313 E. 60th St., Chicago, IL 60637.
November 13-18: Public Works and Municipal Services
Exhibition and Congress, Birmingham, England.
Contact: British Information Services, News Division,
7453rd Ave., New York, NY 10022, (212) 752-8400.
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