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Chapter 5

Current Land-Based Incineration

Technologies



Contents

Page

Tra ditiona l Incinera tion Technologies. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93Liqu id In jection In cinerat ion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93Rota ry K iln In cinerat ion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93

Hea rt h I ncinera tion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96Fluidized B ed Incinera tion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97

Other Incineration-Like Technologies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98Pyrolysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98Wet Air Oxida tion. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98

U se of Air P ollut ion Cont rol an d H eat Recovery E quipm ent. . . . . . . . . . . . . . . . . . . . . . . . . . 98Air P ollution Cont rol Eq uipmen t . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98En ergy R ecovery E quipmen t . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99

Profile of Existing Hazardous Waste Incinerators. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..100Number of Incineration Facilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ................100Location of Incineration Facilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ................101

Incinerator C apa cities and Operat ing Cha ra cteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .101

Chapter5 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .......................104

Tables

Table No. Page

9. Two Estimates of the Number of Land-Based Incineration Units Operatingin the United States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .100

10. Commercial St at us of La nd-B ased Incinerat ion F acilities, by E P A Region . . . . . .. . . ..103

Figures

Figur e No. Page

3. Liqu id In jection I ncinera tion Technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95

4. Rota ry Kiln I ncinera tion Technology. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 955. Fluidized B ed In cinera tion Technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 976. Wet Air Oxida tion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 997. A Regional Profile of Land-Based Hazardous Waste Incineration Facilit ies:

Number of Facilities Located in Each State and EPA Region . . . . . . . . . . . . . . . . . . . . . . .1028. A Profile of the C apa city of La nd-B a sed Incinerat ors for Liqu id Wast es . . . . . . . . . . . . . .103



Chapter 5

Current Land-Based Incineration

Technologies

A variety of technologies ar e used to th erma lly

destroy hazardous wastes. In i ts stric test sense, in-

cinerat ion means the high-temperature destruction

of wastes carried out in the presence of oxygen. For

pract ical purposes, however, certain other thermal

destruction technologies that destroy wastes using

l i ttle or no oxygen (i.e. , pyrolysis and sta rved a ir

incinera tion) can be be grouped w ith incinera tion

technologies.1This section briefly describes the dis-

‘The destruction of hazardous wastes in boilers and furnaces (see

ch. 4) is a common pra ctice that is only beginning to come under reg-

ulation; however, under current regulations (46 FR 7666, J an. 23,1981 ), these practices are distinguished from incineration because

wastes are burned in boilers and furnaces for the primary purpose

of recovering their energy content, not for t he purpose of destroying

the wastes. EPA estimated that, in 1981, almost twice as much haz-

ardous waste was burned in boi lers and furnaces than was burned

in incinerators (4).

t inct ive features of the various processes that ther-

mal ly des t roy hazardous was tes .

All waste incinerators have several common com-

ponents: a waste feed system, a combustion air or

oxygen system, a combustion chamber, combus-

t ion monitoring systems, and (where required) an

air pol lut ion control and ash removal system. The

actual applicat ions of the various components vary

somewhat in different designs. The following brief

description of available incineration technologies

discusses each of these features.

T R A D I T I O N A L I N C I N E R A T I O N T E C H N O L O G I E S

L i q u i d I n j e c t i o n I n c i n e r a t i o n

Liquid inject ion incinerat ion is , by far, the most

common incineration technology used on land (pri-marily onsite), and is the only technology being

used or considered for ocean incineration, As the

name implies, l iquid inject ion incinerat ion can ac-

commodate only freely flowing (pumpable) liquid

or slurry w ast es. When coupled w ith oth er types

of incinerat or designs, this t echnology serves a s a

secondary chamber (afterburner) for volatil ized

consti tuents produced by the primary incinerator.

Liquid injection incinerat ors ar e designed w ith

almost no moving parts and are almost exclusively

single-chamber units. (Figure 3 depicts in schematic

form a typical liquid injection incinerator. ) Wastesa re ty pically injected int o the combustion cham -

ber after being atomized (i .e., broken up into very

fine droplets) by passage through a nozzle or rotat-

ing cup located in or near the burner. A forced air

draft system supplies the oxygen required for com-

bustion an d a lso provides tur bulence to a id in mix-

ing. The combustion chamber itself is typically a

refractory-lined (heat-resistant) cylinder, which can

be mounted either vertically or horizontally.

Combustion gases are vented directly to the

atmosphere, i f they comply with air pol lut ion reg-

ulat ions for incinerators. I f halogenated wastes are

burned, scrubbers capa ble of removing acid ga ses

may be required. Incinerat ion of l iquids usual ly re-

sults only in very low particulate emissions and,

therefore, does not usually require particulate

removal equipment.

Ro t a r y K i l n I n c i n e r a t i o n

Rotar y kiln incinera tion is the t echnology most

commonly used by major commercial land-basedfacilities an d is the t hird most common incinera -

tor design in the U nited Sta tes . Rota ry ki lns can

accommodate a wide range of solid and sludge

wastes , including dry f lowable granular wastes , con-

tainerized wastes, nonpumpable slurries, and semi-

solids. Rotary kilns are generally equipped with sec-

93



94 . Ocean Incineration: Its Role in Managing Hazardous Waste

Photo credit: E.T. Oppelt, Hazardous Waste Engineering Laboratory, US. Environmental Protection Agency

Liquid injection incineration, the most common incineration technology in the United States, is typically used bywaste generators to destroy their own liquid wastes onsite. It is the only technology being used or considered

at this time for ocean incineration.

ondary combustion chambers (afterburners) to of rota ry kiln t echnology a re significan tly h igherincrease the length of t ime during which wastes are tha n t hose of l iquid injection syst ems.subjected to the high temperatures necessary to en-

The combustion cha mber of a rotar y ki ln inciner-sure complete destruction.

a tor consists of a slowly rota ting, refra ctory-lined

The major commercial facilities operate large ro- cyl inder mounted at a sl ight incl ine to aid gravi tyta ry ki lns, coupled with l iquid inject ion units to a c- feed of wa stes. (Figure 4 is a schema tic represen-

commodat e liquid w a stes. Rotar y kiln technology tation of a typical rotary kiln incinerator. ) Solid and

is not currently applicable to at-sea operation, nor sludge wastes enter a t i ts high end, and l iquidis it l ikely to be in the foreseeable future, because wa stes or auxiliary fuel are introduced as neededof design and spat ial constraints . The capital costs th rough nozzles. Ash moves to th e low end of the



Ch. 5—Current Land-Based Incineration Technologies Ž 95

Water-

treatment

for the Office of Technology Assessment (Cambridge, MA: May 1986).

Figure 4.-Rotary Kiln Incineration Technology

Drummed hazardous waste

SOURCE: Arthur D. Little, Inc., Overview of Ocean Incineration, prepared by J.R. Ehrenfeld, D. Shooter, F. Ianazzi, and A. Glazer for the Office of Technology Assessment

(Cambridge, MA: May 1986).



% • Ocean Incineration: Its Role in Managing Hazardous Waste

I

Photo credit: E.T. Oppelt, Hazardous Waste Engineering Laboratory, EPA

Rotary kiln incineration can destroy a wide range ofhazardous wastes—solids, sludges, and liquids—and

is the technology most frequently usedat commercial facilities.

kiln, where it can be removed for disposal. After

being volat i l ized and part ial ly destroyed in the pri-

mary chamber, gases are directed to the second-

a ry cha mber to complete the destr uction process.

Incinerating solid wastes creates appreciable ash

residues and particulate, so rotary kilns are typi-

cally equipped w ith st ack scrubbers to clean flue

gases.

Hea r t h I n c i n e r a t i o n

Hearth incineration, which is the second most

common design in the U nited St a tes, is employed

primarily to burn wastes onsite. Hearth incinera-

tors are designed to burn waste in sol id and sludge

Photo credit: Trade Waste Incineration/Air Pollution Control Association

Fixed hearth incinerators are commonly used to burnsolids and sludges at the site of generation. Thisparticular facility has been equipped with liquid

injection equipment to allow the incinerationof liquid hazardous wastes as well.

form, but they can also be equipped with l iquid in-

jection capability.

Wastes are introduced onto a plat form (hearth)

in the bottom of the combustion chamber. Both

fixed- and multiple-hearth designs are in use.

Multiple-hearth designs, in which wastes are con-

veyed from cha mber to cham ber, are especial ly use-

ful for burning complex wastes that need to be ex-

posed to high temperatures for long periods.

Incinerat ion in fixed hearth units can occur under

conditions of excess air or starved air (pyrolytic)

condit ions. Pyrolyt ic systems are general ly accom-

panied by excess-a ir a fterburners.

Although air f low over the waste mass can be

contr olled to limit t he am ount of par ticulate ma t-

ter in t he exhaust ga ses, scrubbers ar e often nec-

essary to comply with air pollution regulations.



Ch. 5—Current Land-Based Incineration Technologies 97

F l u i d i z e d Bed I n c i n e r a t i o n

Fluidized bed incinerat ion uses a layer of small

part icles (e. g . , sand) suspended in a n upw ar d flow-

ing stream of air. (Figure 5 schematically illustrates

a fluidized bed incinerator. ) The particles behave

much like a fluid (hence, the name). Wastes (anda uxiliar y fuel, i f needed) a re mixed into the sus-

pended bed and combusted. Fluidized bed inciner-

ators were developed primarily to accommodate

highly viscous liquids and sludges not easily burned

in m ore conventiona l ty pes of incinerat ors.

Combustion gases from this type of incinerat ion

typically contain high levels of particulate and,

th erefore, must be scrubbed before release t o the

atmosphere.

Photo credit: GA Technologies, Inc.

Fluidized bed incinerators can destroy liquids andsludges that are not easily handled by more

conventional incinerator technologies,

Figure 5.— Fluidized Bed Incineration Technology

/

ParticulateS o l i d f e e d removal

Waste feed pump \

recycle Trampmaterial

Recycled bed material return

Bed material

Bedmakeup

Stack

Fan

SOURCE: Arthur D. Little, Inc., Overview of Ocean/nc/nerat/on

prepared by J.R. Ehrenfeld D. Shooter, F. Ianazzi, and A. Glazer for the Office of Tech.

nology Assessment (Cambridge, MA: May 19S6).



98 . Ocean /incineration: Its Role in Managing Hazardous Waste

Several other incinerator designs are currently ing ammunit ion and explosives, drum burners, and

in operation. These include fume incinerators (typi- combina tion systems (e. g. , a h eart h connected to

cal ly with l iquid waste incinerat ion capabi l i ty) for a liquid injection unit).

burning ga seous wa stes, incinerat ors for destroy-

O T H E R I N C I N E R A T I O N - L I K E T E C H N O L O G I E S

In addi t ion to the tradi t ional incinerat ion tech-

nologies, two incineration-like technologies for de-

stroying wastes are currently in use.

Py ro l y si s

Pyrolysis refers to technologies that accomplish

thermal destruction in an oxygen-deficient atmos-

phere. Pyr olysis equipment is simila r t o conven-

tional incinera tion t echnologies, with the obvious

exception that i t lacks a system for introducing air

into the combustion chamber. Organic waste com-

pounds ar e volat i l ized a nd part ial ly decomposed by

therm al rea ctions a lone. Ga ses from th e pyrolytic

chamber then pass into a conventional chamber

wh ere they a re combusted in the presence of ex-

cess a ir. One a dvan ta ge of pyrolytic technologies

is that emissions of particulate tend to be lower

than do those from more traditional incinerators

(8).

Three pyrolysisthe Uni ted S ta tes ,

(l).

units are currently operat ing inand several others are planned

We t A i r Ox i d a t i o n

Wet air oxidat ion is a thermal destruction tech-

nology that oxidizes organic contaminants in water .

The w at er modifies oxidat ion react ions so tha t t hey

can occur a t relat ively low t emperat ures (3500 to

650° F). Air is bubbled through the liquid phase,

and the reac tor vesse l i s mainta ined a t a pressure

high enough to prevent excessive evaporation (8).

Wet air oxidation is primarily applicable to aque-

ous waste contaminated with dissolved or sus-pended organic material . The organic content of

wa stes suitable for w et a ir oxidat ion is generally too

low to ma ke tra ditional incinera tion economical,

but sufficiently high to sustain the reaction tem-

peratures needed for oxidation. The technology has

been used successfully to trea t a var iety of a que-

ous was tes contaminated wi th nonhalogenated or-

ga nic compounds, but it h as been m uch less suc-

cessful with halogenated compounds. Moreover, a

secondary process is typically needed, because de-

toxificat ion is incomplete (40 t o 95 percent ).

Figure 6 depicts a typical wet air oxidat ion sys-tem. Several units are currently operating in the

Uni t e d S t a t e s .

U S E O F A I R P O L L U T I O N C O N T R O L A N D

H E A T R E C O V E R Y E Q U I P M E N T

Equipment serving ei ther of two addi t ional func-

tions can be (or is required to be) added to the basic

systems described above. Such equipment includes

devices to control the emission of air pollutants and

devices to recover a nd use a portion of th e energyreleased through incinerat ion.

2

‘This discussion is drawn primarily from refs. 1 and 3; these sources

should be consulted for additional information,

A i r Po l l u t i o n Co n t r o l Eq u i pmen t

Air pollution control equipment is often required

for land-based incinerators, part icularly i f wastes

with significant ash or halogen content are to be

incinera ted. Such equ ipment consists of two com-ponents. The first is a quench chamber or heat ex-

changer to cool the ga ses leaving t he combustion

chamber. The cooling is necessary for efficient oper-

at ion of air pol lut ion controls located downstream.



Ch. 5—Current Land-Based /incineration Technologies • 99

Figure 6.— Wet Air Oxidation

Feed tank 1

Heat exchanger

LOW pressure High pressurefeed feed pump

I

Compressedair

Heat exchanger2

Reactor

Off-gas

Oxidized liquor

Cooler PressureCooling

Separatorcontrol

water release

SOURCE: Arthur D. Little, Inc., Ovendew of Ocean /nc/neration prepared by JR Ehrenfeld D. Shooter, F. Ianazzi, and A. Glazer for the Office ofTechnology Assessment (Cambridge, MA: May 1986 .

The second component includes one or more

scrubbers for actually cleaning the gases. Major

commercial incineration facilities typically remove

particulate by using wet or dry electrostatic precipi-

ta tors, venturi scrubbers, or, less commonly, fa b-

ric f i lters. Removal of gaseous polluta nts, includ-ing corrosive acid gases, usually requires a wet

scrubber, which neutral izes gases through contact

with an alkal ine l iquid reagent . Operat ion of a wet

scrubber requires instal lat ion of a mist el iminator

downstream, to separate the flue gases from water

droplets containing contaminants. (For a ful ler dis-

cussion of scrubbers, see app. B in ref. 6.)

Both par t i cula te and gaseous po l lutant removal

systems generate waste s ludges that , a long with ash

residues, are typically handled as hazardous wastes

and disposed of in hazardous waste landfills.

Ene rg y Recove r y Equ i pmen t

En ergy recovery equipment is not requ ired un-

der current regulat ions but is sometimes instal led

on hazardous waste incinerators if it is deemed eco-

nomical ly feasible and advantageous. Such equip-

ment genera lly ca n only be insta lled upstream from

air pollution control equipment, that is, prior to

removal of corrosive gases or particulate. Inciner-

at ion of wastes generat ing these products may dam-age or interfere with the operation of energy re-

covery equ ipment a nd, t herefore, often precludes

its use. Cert ain modifica tions ha ve recently been

introduced to partially alleviate these design re-

strictions.

Energy is general ly recovered through the pro-

duction of steam, which can be used to generate

electricity, to drive machinery, or to provide heat.

Alternatively, energy can be used to heat the air

fed to the incinerator, thereby increasing combus-

tion efficiency and reducing the need for auxiliary

fuel.

Typical energy recovery equipment consists of

watertube or firetube boilers capable of recovering

60 to 80 percent of the heat content of combustion

gases .



100 Ocean Incineration: Its Role in Managing Hazardous Waste

P R O F I L E O F E X I S T I N G H A Z A R D O U S W A S T E I N C I N E R A TO R S

This section, which is draw n la rgely from E P A

documents, sum ma rizes ava ilable informat ion on

the number, capaci ty , and characterist ics of exist-

ing land-based hazardous waste incinerators. OTA

has found tha t these da ta are incomple te and onlyprovide rough estimates, even of seemingly straight-

forward stat ist ics , such as the number of permitted

hazardous waste incineration facilities currently

operat ing in the United States. No rel iable nat ional

database containing such information currently ex-

ists. Moreover, the number and permit status of

incineration facilit ies is constantly changing, as per-

mits a re processed or fa cilities open or shut down

in response to various regulatory or economic,

factors.

Despite these deficiencies, data derived from sev-

eral sources can be used to develop a profile of ex-isting facilities.

Numbe r o f I n c i n e r a t i o n Fac i l i t i e s

EP A ha s estima ted th a t a bout 240 to 275 oper-

at ing hazardous waste incinerat ion faci l i t ies exist

in the Uni ted S ta tes .3This estimate emerged from

several independent studies, including those basedI

‘This estimate excludes industrial boilers and furnaces, which are

not considered incinerators under current regulations. These facilities,

are numerous in the United States, and they currently account for

the destmction of substant ially more hazardous waste than do inciner-

ators (see ch. 4).

on the Westa t n at iona l survey (10), interviews w ith

incineration manufacturers, a survey of RCRA

P art A permit a pplicants l is ted in the EP A Ha z-

a rd o us Wa s t e D a t a M a na g eme nt S y s t e m, a nd d a t a

from EPA Regional Office permit files.

As of J uly 1982, EP A had identi fied 271 haza rd-

ous wa ste incinerat ion fa cilities using 352 opera-

tional incineration units (3). Based on 1985 per-

m it d a t a , h ow e ver , t h is es t im a t e w a s r ev is ed

downward, to about 240 faci l i t ies using about 310

incineration units (5). The reduction in part

reflected the fact that some facilities ceased opera-

t ions instead of securing f inal Part B RCRA

permits.4

Table 9 presents two est imates of the number of

incinerators of each design that were in use in 1981

(3). One estimate (shown in column A) was derived

from interviews with incinerator manufacturers re-

garding the number and type of units sold in the

United States. The other (column B) was extrapo-

lated from part ial data obtained from applicat ions

for RC RA Pa rt A permits. These estimat es gener-

al ly agree regarding l iquid inject ion and hearth in-

*Complicating m at ters furt her, OTA recently obtained a computer

printout from the Hazardous Waste Data Management System of in-

cinerator facili ties that had submitted permit applications as of May

1986. This source listed a total of 274 incineration facilities with pend-

ing applications, but i t did not provide any information concerning

incinerator design or commercial status. In this discussion, the data

from this source will be used as the most current available data.

Table 9.—Two Estimates of the Number of Land-Based incineration UnitsOperating in the United States

Estimate Aa

Estimate Bb

Number Percent Number Percentof units of total of units of total

Liquid injection . . . . . . . . . . . . . . . . . . . . . 219 650/o 213 61 ‘/0

Hearth (total) . . . . . . . . . . . . . . . . . . . . . . . 70 21 75 21

Hearth (with liquid capacity). . . . . . . . — — (44) –Hearth (solids only) . . . . . . . . . . . . . . . – — (31) –

Rotary kiln (total) . . . . . . . . . . . . . . . . . . . 37 11 17

Rotary kiln (with liquid capacity) . . . . – — (15) 5Rotary kiln (solids only) . . . . . . . . . . . . — (2) –

Fluidized bed. . . . . . . . . . . . . . . . . . . . . . . 9 3 5 1

Other or unspecified . . . . . . . . . . . . . . . . — — 42 12

Total . . . . . . . . . . . . . . . . . . . . . . . . . . . . 335 352

e t lm te A is derived from interviews with incinerator manufacturers regarding the number and type of units sold in the United 3atea.

bE9timate B ia ~ j on extrapolation from partial data obtained from R R

part Permit applicant.

SOURCE: E. Keitz G. Vogel, R. Holberger et al., Arofil

ofEx/st/ng

Hazardous WasteInchreratlorr

FacH/tiesand

h4anufac

turera in the Un/ted States, EPA No. S00/2-84452, prepared for the U.S. Environmental Protection Agency, Officeof Research and Development VWahington, DC: 19S4).



Ch 5—Current Land-Based Incineration Technologies • 101

cinerators but di ffer significantly regarding rotary

ki lns. (Note th at these est ima tes w ere derived from

1981 dat a ; the tota l number of units ha s changed

since 1981, but revised data for the distribution

among different designs are not available. )

The data from Est imate B in table 9 indicate thatalmost 80 percent of hazardous waste incinerators

have some capacity for burning liquid wastes.

Data on the use and nature of air pol lut ion con-

trol equipment on land-based incinerators are

scant . Based on da ta obta ined from appl icants fo r

RCRA Part A permits, EPA (3) estimated that

a bout 45 percent of exist ing incinera tors ha ve some

form of air pollution control equipm ent . About 37

percent of existing units use some type of scrub-

ber. Large incinerators and those employing higher

temperatures and longer residence times were more

l ikely t o ha ve a ir pollution contr ol equipment.

EP A (3) a lso found tha t only a bout 22 percent

of existing incinerators used energy recovery

equipment. Energy recovery equipment is more

commonly found on incinerat ors burning liquids,

on larger incinerators, and on incinerators oper-

ating on a continuous basis.

Only six incinera t ion faci l it ies a re currently per-

mitted to incinerate P CB s, as provided under the

Toxic Substances Control Act. See box B in chap-

ter 3 for a more detailed discussion of PCB in-

cinerat ion.

Loca t i o n o f I n c i n e r a t i o n Fac i l i t i e s

This section considers both the regional distri-

bution and the commercial status (i.e. , onsite versus

offsite) of existing incineration facilities. For the 274

faci l i t ies for which data were avai lable, f igure 7 in-

dicates the number of facilit ies located in each State

and EPA Region. Table 10 presents the commer-

cial st at us of the 227 facil i t ies wh ose sta tus w as in-

dicated in reference 3.

Several conclusions can be drawn from these data

on regional distribution. First, as w as t rue for in-

cinerable waste generat ion, the distribution of haz-ardous waste incinerators is concentrated in par-

t icular States and regions. (For example, as shown

in f igure 7, EPA Regions V and VI each contain

about one-fifth of all facilit ies. Texas alone accounts

for almost one-eighth of all facilities. ) Second, the

Northw estern U nited Sta tes , in general , conta ins

few incineration facilities, and EPA Region VIII

conta ins no commercial facilities. Finally, the great

ma jority (80 percent) of existing ha zar dous wa ste

incinera tors a re privat e faci l it ies located onsi te . No

correlat ion is a pparent between onsi te or offsi te in-

cineration and regional distribution.

EPA also examined the sources of waste burned

by the incinerators covered in its survey. Of the

respondents, 77 percent identif ied wa ste t hey in-

cinerated as having been generated onsi te . Of the

23 percent that reported handling waste generated

offsite, 90 percent were commercial incinerators (3).

I n c i n e r a t o r Capac i t i e s and Ope ra t i n g

Cha r a c t e r i s t i c s

Exist ing incinerators have been further charac-

terized with respect to their capaci ty for l iquid andsol id wa stes an d the tempera tures a nd residence

t imes at tained under typical operat ing condit ions.

C a p a c i t y

For 180 of the incinerators surveyed by EPA (3),

capacity for liquid wa stes w a s specified. Figure 8

shows th e ran ge of capa cities.

According to these data, the capacities of two-

thirds of exist ing incinerators for l iquid wastes are

below 300 ga l/hr (2,500 lbs/hr ). The m edia n ca -

pa city for liq uid w a st es is 150 gal/hr (1 ,250 lbs/hr ).

Similar data for incinerators burning sol id wastesrevealed a median capacity of less tha n 80 gal/hr

(650 lbs/hr ), or a bout h a lf of th e media n for liq -

uids. Assuming that the faci l i t ies were operated at

an average of 55 percent capaci ty , as est imated by

EPA (9), the median capaci t ies would translate into

annual throughputs of about 1,400 metric tons for

solid w a stes a nd 3,000 metric t ons for liquids.

These data can be compared to the burning rate

for l iquid wastes incinerated at sea. Each of the in-

cinerators on the Vulcanus ships has a capaci ty of

a bout 1,650 gal/hr, or a bout 11 times t he media n

for land-based incinerators. The Apollo ships aredesigned to have an even greater capacity, about

2,750 ga l/hr per incin era t or (7). Only 2 percent of

al l land-based incinerators have a reported capac-

i ty great er th a n 2,000 ga l/hr, a nd a bout 4 percent

ha ve capacity great er t ha n 1,000 gal/hr.



102 • Ocean Incineration: Its Role in Managing Hazardous Waste

Figure 7.—A Regional Profile of Land-Based Hazardous WasteLocated in Each State and EPA Region

Incineration Facilities:(Total of 274 facilities)

Number of Facilities

2 ( D E )

10 (MD)

I

SOURCE: Data based on a commter rxlntout from the Hazardous Waate Data Management System of incinerator facilities that had submitted Dermit atmlications aa of May 19S6.

The large commercial rotary kiln incinerators in

use today have annual throughputs of about 20,000

to 35,000 metric tons of mixed wastes,5w h e r e a s

existing ocean incineration vessels could each burn

50,000 to 100,000 metric tons of liquid wastes an-

nua lly (refs. 2,9; an d da ta from incinerat ion ves-

sel owners).

Combustion Zone Temperature and

Residence Time

According to EPA (3), the average combustion

zone tempera ture in those incinerat ors for w hich

5I f these incinerat ors were to burn only liquid wa stes, the capacity

would be considerably higher.

da ta were a vaila ble wa s 1,820 + 2250 F (993 +

1070 C). For liquid injection incinerators, the aver-

a ge wa s slight ly high er, 1,857 + 224° F (1 ,014 +

1070 C). In both cases, the median temperature

was about 1,8000 F. Liquid injection incinerators

genera l ly opera te a t higher tempera tures than do

rotary ki lns, because the former do not require as

much excess air to atomize and combust liquid

wastes .

With r espect to residence time, EP A data indi-

cate that about half of the incinerators for which

data were provided had residence times of 2 secondsor longer, and only about 15 percent had residence

times under 1 second, Liquid injection incinera-

tors had a similar distribution.

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