SOLID WASTES  HANDLING
in hospitals
REPRINTED FROM PUBLIC HEALTH SERVICE PUBLICATION NO. 930-C-16

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REPRINTED FROM
environmental aspects of the hospital
HOSPITAL AND MEDICAL FACILITIES SERIES, THE HILL-BURTON PROGRAM
                   volume II. supportive departments

                        CHAPTER II.  SOLID WASTES HANDLING
                                            Ralph J. Black
             U. S. DEPARTMENT OF HEALTH, EDUCATION, AND WELFARE
                                        Public Health Service
          CONSUMER PROTECTION AND ENVIRONMENTAL HEALTH SERVICE
                               Environmental Control Administration
                                           solid wastes program
                                              CINCINNATI
                                                  1968

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Chapter  II
              SOLID   WASTES  HANDLING
                                                       Ralph J. Black
  THE DIVERSIFIED TYPES of solid wastes that must
be stored, collected, and disposed of in  the  oper-
ation of medical  care institutions create problems
that should be  recognized  early  in  the planning
process.  Adequate  facilities  for the types  and
amounts of  waste that must be handled; the loca-
tion and design of waste chutes, and design of waste
rooms;  whether  separate  facilities  are to be  pro-
vided  for  the  disposal of surgical  and autopsy
wastes; and the method of  disposal are all essential
factors to consider for both new or remodeled  facil-
ities. Consideration  should be  given  to  on-site
incineration or hauling for off-site  disposal,  with
emphasis on the placement and type of incinerator
if incineration is chosen.  Suitable  storage, collec-
tion, and conveyance systems must be evaluated,
keeping  in mind such factors as  the size of waste
containers,  facilities for   cart  and/or  container
washing, whether garbage grinders can be used,  or
whether  a refrigerated room must be provided for
storing the garbage until removed.
            TYPES  AND VOLUME

  The principal  types  of solid  wastes are:  (1)
garbage,  (2)  paper,  trash, and  other dry  com-
bustibles,  (3)  treatment  room wastes,  (4)  surgery
wastes,  (5)  autopsy  wastes, (6)  nbncombustibles
such as  cans and bottles.  All containers and equip-
ment should be readily cleanable,  small enough for
one  man  to handle  easily when  full,  covered as
tightly as practicable until filled, and constructed
to create as little noise as possible during handling.
Ideally, collection  must create a minimum of dis-
turbance,  yet  be  scheduled frequently enough to
minimize accumulation of odors and prevent  over-
loading  of storage,  transportation, and  disposal
equipment.
  Solid waste handling systems should prevent air-
borne  contamination, vermin  attraction,  and odor
production.  The system  should encourage neatness
and good housekeeping, and present no safety haz-
ards to the institution or its employees.  It is par-
ticularly  noteworthy that  studies  of  the micro-
biological contamination of hospital air showed tb.3
heaviest  contamination in waste storage  and  di1-
posal areas, particularly in chute closets.1 In view
of the well-documented difficulties  experienced  in
controlling hospital-acquired infections, good super-
vision  must  assure that the most scrupulous house-
keeping  standards  are  maintained  in   handitng
solid wastes.
  Average weight and volume of solid wastes have
been given by  several workers  as  between 7  and
8^2 pounds,  and  about 0.7  cubic foot per paoient
per day.  Unfortunately,  there is no reliable cur-
rent information on average refuse production. The
increasing use of disposable items has undoubtedly
altered former average figures on types  and quanti-
ties  and has affected  incinerator  loadings.  The
problems inherent in safely disposing of such items
as syringes,  examination gloves, catheters, emesis
basins, and petri dishes by means of outdoor stor-
age and municipal collection, involve special safety
considerations for  staff,  collectors,  and the public.
There  are legal implications as well. For example,
used syringes recovered from landfills or dumps by
children who play doctor or use them for darts, or
by narcotics addicts for less innocent purposes, may
leave the hospital liable  for  legal  action through
failure to destroy or safely dispose of them.
  Most existing data on waste type and "\ olume are
  Mr. Black is chief of the Solid Wastes Engineering Sec-
tion, Special Engineering Services Branch, Division of En-
vironmental Engineering and Food Protectiou, US. Public
Health Service.
20

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calculated  on a pounds-per-patient-per-day  basis.
There are shortcomings in using the patient day as
a unit for estimation, however.  It has  been sug-
gested that a better correlation can be obtained by
using an  equivalent  population  computed  from
total patients,  resident and part-time staff  mem-
bers, and estimated visitor load. Charts II and III,
                                          using the equivalent population basis, show the re-
                                          sults of one waste production survey.
                                            Single-service plastic waste receptacle liners or
                                          moisture-proof  paper bags with special holders  are
                                          preferable to unlined  metal containers  with  their
                                          attendant sanitizing  requirements or  cloth  bags
                                          which  require  laundering.  Specially  designed
            Chart II.  Hospital Noncombustible Wastes Production on  Volume  per
                                       Capita per Day Basis*
                                                               1000
                                                                              1500
                                            Equivalent Population
        I
        h.
        
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single-service cardboard  cartons  have  also been
used successfully.  (See figures 3 and 4.)
  Trash chutes  should discharge to  a trash receiv-
ing room separate  from  the  incinerator  charging
areas, and the receiving room should have exhaust
ventilation. Chute loading doors  should be located
in soiled-equipment  areas or  in  closets  separated
from  corridors  or  clean   areas.   Charging  doors
should be protected with electric  interlock systems
to prevent the opening of  more than one  door at a
Figure 3.  Housekeeping cart with bulk container  lined
  with plastic bag.
Figure 4.  Trash receptacle from isolation room show-
  ing  impervious  paper  liner.  Receptacles from non-
  isolation rooms should  also be lined.
time, and should  be  tightly  fitted with  flexible
gasketing to minimize  the  spread of aerosols from
the chute.  Chutes and trash receiving rooms should
have adequate  sprinklers  for  fire  protection, and
incinerator  operating periods should be  scheduled
to minimize trash buildup in both areas.  (See figure
5.)
  The use of single-service container  liners, paper
bags, or cardboard cartons  reduces  aerosol spread,
eliminates odor and  noise produced in  transferring
the refuse,  and achieves better vector control  be-
cause the metal supports or receptacles do not ac-
cumulate much gross soil.  Rupture of  plastic bags
of 0.0015 to 0.0020 gauge has been  reported as in-
frequent  even  when used  for cans  and  bottles.
Overloading,  however, particularly  with wet  gar-
bage, inust be controlled by staff training and super-
vision.  After filling, liners should  be  closed with
rubber bands or stapled. Paper bags are  less liable
to  rupture  but have thus  far been employed  in
relatively limited quantities.  (See figure 6.)
Figure 5.  Trash chute receiving  room should  be sepa-
  rate from charging area, fire sprinklered and, if pos-
  sible, have hose bibs to permit periodic scrubbing.
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Figure 6.  P?per  bag for bulk trash collection mounted
  in special holder with stapler for closing.
  Plastic  bags  for larger (27 to  33 gallon)  con-
tainers may  not feed  readily through  waste chute
doors; the use  of smaller containers and  bags or
small cardboard cartons may be necessary. Metal
containers from  which liners  are  removed should
have closely  fitting lids, either detachable or of the
hinged,  foot-operated  type.  Containers  should be
constructed  without  open  seams  or  crevices for
easy  cleaning.   The  container  and  cart-washing
facilities should be located as close together as pos-
sible so that the same hot water and steam supply
can be  used. If steam is used, it must be under
pressure to be' effective in  open containers or for
carts. Whether 180° F. water or steam is  used for
sanitizing, a thorough initial hot water wash with
detergent is necessary  to remove the gross soil from
containers.   The operation  should  be mechanized
as much as possible to reduce  labor and to encour-
age  frequent  washing of   this equipment.  (See
figures 7 and 8.)
  Although impervious liners reduce the necessary
frequency for  sanitizing  containers, all  containers
and the carts on which they are transported should
be  cleaned  routinely, as  frequently  as  facilities
                                                     permit, without waiting for accumulation of clearly
                                                     visible gross soil. Fabric hampers, if used to trans-
                                                     port sealed liners, should be laundered on alternate
                                                     days.  They  should  never be  used  for  carrying
                                                     pathogenic wastes.
                                                                  GARBAGE DISPOSAL

                                                       Many  institutions use garbage  grinders.  But in
                                                     some  areas,  local ordinances prohibit the use  of
                                                     commercial,  heavy-duty  garbage grinders of  the
                                                     type best suited to institutional  use.  Special agree-
                                                     ments, which sometimes include a service charge to
                                                     cover the additional sewerage treatment load, have
                                                     been negotiated between local authorities and  hos-
Figure 7.  Can cleaner with 180 °F.  water connections.

Figure 8.  Can cleaner with can positioned for cleaning.

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pital administrators.  The use of grinding units for
disposing of placental  wastes  and other hospital
service department wastes, as well as the more cus-
tomary kitchen wastes, should be evaluated.
  An approximate guide for estimating commercial
disposer capacity in  kitchen  uses is shown below:

  Horsepower           l/z    %    IVa       3
  General capacity
     Ibs/hr            200   400  1,200   2,000
  Up to number of
     persons per
     meal              125   300  1,500   1,500 plus

  The pounds-per-hour  capacity is  based on  use of
 a special mixed waste developed as a military spe-
 cification.
   The size  of grind is important in  making the dis-
 charge  acceptable  for  handling in  the  sewerage
 treatment system. The  following specifications are
 based on the military specification used in table III:
   1. 40 percent of  discharge must pass a  No. 8
 sieve.
   2. At least 65 percent shall pass  a No. 3 sieve.
   3. 100 percent shall pass a V£" sieve.
 Table III.  Basis  for Determining Pounds-
       Per-Hour Capacity of Disposer*
Material
Uncooked beef or pork bones not over
  IM:" diameter
Uncooked poultry bones
Grapefruit rinds cut in half
Green beans, cooked
Turnips, cooked
Spinach, cooked
Whole beets, cooked
Banana skins
Lettuce leaves, raw
Raw vegetable trimmings
Raw celery stalks
Corn husks
Potato peelings
Paper napkins
                                     Approximate
                                   Percent Drained
                                       Weight

                                         10
                                         10
                                         15
                                          5
                                          5
                                          5
                                          4
                                         10
                                         10
                                          5
                                          5
                                          5
                                          5
                                          4
  * Specifications Military—G-1584OB, Para. 4.1.1.1.
  The unit should be  approved  by Underwriters
Laboratory and installed with a backflow preven-
tion device. The impellers and fly wheel should be
corrosion  and  jam resistant;  the motor  of ball-
                                                   bearing,  sealed  design;  and the unit should  have
                                                   an  inlet  deflector of neoprene or other approved
                                                   elastomeric  material.  Approved  sanitary  instal-
                                                   lation  principles for easy cleanability and  mainte-
                                                   nance  should be followed.
                                                     If garbage  cans are  used,  as  they are in many
                                                   dietary  facilities on nursing  floors,  plastic liners
                                                   are  very useful in  reducing  the amount of  gross
                                                   soil  that accumulates in the cans.  If garbage must
                                                   be  sorted, rather than  ground or  incinerated, and
                                                   hauled away at  the end  of  a  shift, refrigerated
                                                   storage should  be provided.  This  retards spoilage,
                                                   reduces  odor production,  and greatly  reduces  fly
                                                   and rodent attraction during  warm  weather.  Out-
                                                   side storage of cither garbage or  rubbish  requires
                                                   containers  that  arc  tightly covered, easily clean-
                                                   able,  and positioned on a rack 12  inches  off the
                                                   ground  for a  single rack  of  cans,  and 18 inches
                                                   above the ground if  a double  rack is used.  Galva-
                                                   nized  pipe  of  lVi> inch diameter  is often  used  to
                                                   construct racks because the  pipe is durable and
                                                   easy to clean.
             RUBBISH DISPOSAL

  Since incineration facilities  must be provided for
the disposal of  infectious wastes, many institutions
have built incinerators large  enough to handle all
their refuse. While enough large cardboard cartons
accumulate in large hospitals  to warrant flattening
and selling them, the local demand for cardboard is
variable.  Similarly, there may be a  minor local
market for large-sized  tin  cans  to  be  used by
nurseries to plant trees and shrubs.  However, such
salvage does not significantly  reduce  the volume
of refuse which must be handled.
  Equipment for wet grinding or pulping of refuse,
followed by dewatering of the pulp, has been intro-
duced  recently.  This equipment has the advantage
that both garbage  and trash  can be handled, and
since the slurry can be pumped  easily,  the extract-
ing unit can be  located where  removal of the de-
watered pulp is convenient.  Little water is used by
these units because the extracted water is recycled.
The principal  disadvantage of this  method  is that
a damp pulp is produced which is  best disposed of
by landfilling or  composting.
  Such specialized  problems as  destruction of limb
or body casts  can only be handled  in heavy-duty,
high-temperature   incinerator  units   after  first
breaking the casts into small segments.  One special
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problem which has occurred in institutions having
an  appreciable  amount of bone wastes, such  as
teaching  hospitals  which use  numbers  of experi-
mental animals, is fused phosphorous deposits  on
grates  or  bricks in combustion chambers.  These
deposits,  which  are much harder than fused glass,
are usually removed by  periodic chipping or the
replacement of some of the  brickwork or grates.
       HOSPITAL  INCINERATOR TYPES

  Two  principal  types  of  multiple-chamber  in-
cinerators are currently in use—natural-draft, and
heavy-duty, high-temperature. The latter is pref-
erable  because the high temperatures  provide safe
disposal of pathological and laboratory wastes, wet
garbage, and  other  high-moisture-content  mate-
rials.  The  obsolete flue-fed incinerator with direct
charging from the  waste chute,  was  convenient
because it  permitted  loading at each floor.  But it
had a high  level of faulty operation and breakdown,
created aerosol contamination around  flue  doors,
into  hallways and patient areas, and  had serious
limitations on handling high-moisture  wastes.  The
natural-draft type offers improvement in operating
temperatures  but  little certainty of complete de-
struction  of  pathological materials.   The  high-
temperature type  of  incinerator  of  either grate  or
solid hearth  construction,  with  drying shelves  for
wet wastes and an auxiliary  heating unit to insure
temperatures of 1200° to  1800°  F. is  the  unit  of
choice.
  There are  various  devices to  aid in  controlling
particulates in the gases emitted  from an inciner-
ator.  The  settling chamber provides an additional
compartment in which fly-ash particles impinge on
the surfaces  or, if  large enough,  settle  out  as the
hot gases  pass  through the chamber.  The same
effect is usually accomplished by proper design  of
a  multiple  chamber incinerator.  Design  of the
secondary  combustion chamber  and its flue con-
nection should afford a 90°  angle, forcing a sharp
directional change in the  movement of combustion
gases.  The natural impingement  of particles, sup-
plementing  that   accomplished   earlier  by  the
baffles between the primary  and  secondary  cham-
bers, will remove  a high  proportion of  particulate
matter. As always, proper charging practices and
sufficiently high operational  temperatures are also
necessary for good results.
  A second device for particulate  removal is the
liquid  scrubber  or  gas washer,  operated  on these
basic principles:
  a. Wet impingement—Particulates  impinge on
baffles with  water flowing over their surfaces.
  b. Water  sprays—Spray jets in the flue breech-
ing wash the gases in passing.
  c. Water  curtain—A continuous curtain is di-
verted by baffles through which the flue gases pass.
  Particulate removal devices are designed more
for air-pollution control  than as safety devices to
prevent emission of pathogens.  Adequate destruc-
tion of pathogens  is only  accomplished  by suffi-
ciently  high  temperatures in  auxiliary  burning
units,  and  particulate removal  should never be
viewed  as a  substitute  for high-temperature  de-
struction.
  Heavy-duty incinerators can be equipped with a
heat-exchange coil  to  provide hot water or steam
for sterilizing waste  cans. In many cases, irregular
incinerator operating schedules  and the relatively
low BTU value of refuse, even if no high-moisture
material  is  incinerated,  offer  marginal  benefits.
However, one author  indicated that in a  "fairly
large"  hospital, heat recovery could mean a saving
of $100 or more per month.2 The determination to
make the added capital  investment  necessary to
recover waste heat should be evaluated by a quali-
fied  mechanical  engineer  after data  on  average
waste composition have  been collected.  Local air
pollution  control requirements  always should be
investigated  before installing  or  modifying an
incinerator installation. Detailed operating instruc-
tions should be mounted on the  incinerator control
panel or nearby  wall. The manufacturer's repre-
sentative should review operating procedures  with
the engineer or foreman responsible for incinerator
operation and maintenance.
  Classification  systems have been suggested for
incinerator types to furnish some guidance in select-
ing appropriate units.3'4
        OPERATIONAL AND  SAFETY
              CONSIDERATIONS

  In organizing  solid wastes disposal work, super-
vision must be strict and constant, with the respon-
sibility  delegated to  one  individual.  Housemen
performing collection and storage work should  be
carefully  trained  in  protective techniques neces-
sary for the proper handling of pathogenic wastes,
such as the use of gloves, gown, filter mask; meth-
                                                                                                  25

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         ods of  handling containers to  minimize  aerosol
         spread;  and proper closure techniques if liners  are
         used.  All wastes from infectious disease cases,  in-
         cluding  food wastes,  should be  placed  in  clearly
         marked plastic or paper bags and incinerated.  Only
         trained personnel, wearing gloves or  other  protec-
         tive items, if necessary, should handle these  wastes.
         Pathogenic   wastes  from  treatment  rooms,  burn
         dressing rooms,   autopsy  wastes,  items such  as
         sputum cups and tissues  from  tuberculosis wards,
         pathogenic  laboratory wastes,  and  experimental
         animal tissues all require careful  handling of waste
         receptacle  liners, together with  strict observation
         of protective techniques by collecting personnel.
          Scheduling of  collection  must depend on  local
         conditions,  but  refuse should be  removed  at fre-
         quent  intervals in as sanitary and as quiet  a  man-
         ner as possible.   Since  no  firm scheduling of refuse
         removal from operating  and  delivery rooms  is
         feasible,  frequent  checking with supervisors  is
         necessary to provide adequate service. If only one
         service hall  and  entrance  in the  building is avail-
         able,  the  food  facilities   are  frequently  located
         nearby.  In  such cases, refuse  removal  should be
         scheduled during periods of the  lowest level  of food
         preparation and  service. To minimize aerosol haz-
         ards and relieve  hallways and  service elevators of
         extra traffic, no collection  should  be scheduled dur-
         ing  mealtimes.   If  flue-fed  incinerators are  still
         being  used, particular attention  must be given to
         training housemen and others handling wastes  not
         to  empty  noncombustible or pathological  wastes
         into the chutes.  Waste receptacle liners must not be
         overloaded  to the point that the  bags are ruptured
         by   forcing  them  through  hopper  doors.  Liners
         should be routinely  used in kick-buckets in  surgery
                    and delivery rooms.  Proper training of housemen
                    in the  use  of waste-can liners or cartons makes  it
                    unnecessary to  use nursing  personnel  trained in
                    isolation and  protective  techniques  to  handle in-
                    fectious waste disposal.  (See figures 9, 10, and  11.)
                      Medicines  which contain  alcohol, empty  con-
                    tainers  with residual  hydrocarbon products, trash
                    saturated with inflammable liquids, and pathogenic
                    wastes all constitute safety hazards if spilled in the
                    incinerator  charging  process   or  thrown  into  a
                    closed-down  but   still  hot incinerator  chamber.
                    Transparent face shields  are used routinely  to  pro-
                    tect the eyes of municipal  incinerator stokers,  and
                    should be  used  by hospital incinerator operators.
                    Any introduction  of material  into the  incinerator
                    after routine operating hours should  be closely su-
                    pervised.  When pathological remains which  have
                    been preserved in alcohol are incinerated, additional
                    air must be provided to keep  down  the  heat  and
                    smoke generated. The operating temperature should
                    be  brought up  to  about  1700° F.  by  auxiliary
                    burners and blowers when  starting to incinerate a
                    new load of wastes. After  the  load is charged, the
                    fuel supply should be cut off, but the blowers should
                    be  left running to  provide sufficient air for  good
                    combustion.
                      In new installations, facilities for vacuum clean-
                    ing incinerators, rather than sweeping and  shovel-
                    ing, should be  investigated.  One municipal-sized
                    operation reported  a reduction  in work force  from
                    6 to 2 men and cleaning time  reduced  from 36 to
                    5 hours a  week.  Additionally,  the vacuum  process
                    eliminates  the  need for workmen  to use the  pro-
                    tective  clothing and  respirators required  by the
                    manual process.5
                      Safety controls  required  on  gas-fired  incinera-
Figure  9.  Bulk waste can with  plastic
  liner  for  wastes  from isolation area.
  Smaller  individual  can  liners  from
  patient rooms are placed in lined larger
  can.
Figure  10.  Houseman  closing  neck  of
  liner before fastening. Note that proper
  sized liner cuff permits enough slack for
  adequate closure without  compressing
  waste inside.
Figure 11.  Both fastened liner and tight-
  fitting can  lid are tagged with warning
  tag to protect subsequent handlers and
  insure adequate disposal of infectious
  wastes.

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tors should  be (1) draft  indicators,  (2)  pilot light
solenoid, (3)  low voltage release  relay on  blower,
and  (4)  damper interlock.  All  these safeguards
should  be in  series with  a solenoid  shut-off valve
in  the  gas  supply  line,  which  will  operate  upon
failure  of any of the safety components.
  Routine safety inspections by insurance inspectors
should  be encouraged,  since  their training makes
them sensitive to any installation where a foresee-
able  set  of circumstances might  cause  accidents
or fire.
  Some routine  operating instructions which pro-
long incinerator life  are:
  1. Clean grates and ash pits daily.
  2. Keep all draft passages  clean.
   3.  Operate  dampers weekly.  Pulleys may cease
to function because of ash dust.
   4.  Keep cans, bottles, and other noncombustibles
out of the incinerators.
   5.  Ventilate furnace well  before lighting  to  re-
duce  explosion hazards from accumulated fumes.
   6.  Don't overload furnace.
   7.  Keep materials  stirred and  loose,  exposing
them to air so they will  burn readily.
   8.  Give a smoking  fire more air.
   9.  Don't strike  brickwork  with bars or  rakes.
 10.  Learn  what  types  and  amounts of  wastes
may  safely  be  burned   without  overheating  the
brickwork.6
                                                 REFERENCES
1.  Greene, V. W.. et al. "Microbiological Contamination of
   Hospital  Air; I. Quantitative Studies, II. Qualitative
   Studies,"  Applied Microbiology, 10: 561-566 and  10:
   567-571, November  1962.
2.  Deming, Emily C. "How To Remove Waste To Remove
   Hazards," Modern Hospital, 91: 130, Oct. 1958.
3.  Mohr, Orpha. "The Selection of Incinerators for Hos-
   pital Use," Hospital  Management,  85:  118, February
   1958.
4.  Incinerator Institute of America.  Incinerator Standards.
   New York: The Institute, April 1963.
5.  "Incinerator Vacuum  Cleaner Cuts  Labor Costs," The
   American City, 71: 136, March 1956.
6.  Koppenhauer, 0. E. "Incinerator of Hospital Wastes,"
   Hospitals, 35: 91, May 1, 1961.
                                           ADDITIONAL READING
Bond, R. G., and Michaelsen, G. S.  Bacterial Contamina-
  tion from  Hospital Solid Wastes.  (Final  Report, PHS
  Research Grant EF-00007-04) University of Minnesota.
Cadmus,  R.  R.  "One-Use  Waste Receptacles Minimize
  Infection Spread," Hospitals, 32:  82-84, Dec. 16,  1958.
Hurst, Valerie, et al. "Hospital Laundry and Refuse Chutes
  as  Source  of  Staphylococcic  Cross-Infection," JAMA.
  167: 1223-1229, July 5, 1958.
James,  P. E.  Equipment  and  Methods  for HeaL-Treating
  Garbage for Hog  Feed (U.S. Dept.  of Agri. Program  Aid
  No. 370), November 1958.
Los Angeles County Air Pollution Control District. Multi-
  ple-Chamber Incinerator Design Standards for Los Angeles
  County. Los Angeles:  The District, 1960.
Paul, R. C. "Disposables in Hospital Plant Operation Func-
  tions."   Presented to The Invitational  Conference  on
  Utilization of Disposables in Hospitals, American Hospital
  Association, Chicago, 111., 1964.
Vincent, C. L. "Careful  Use of  Plastic Liners Eliminates
  Need  for Cloth Bags," Modern Sanitation 
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