vvEPA
                                 United States
                                 Environmental Protection
                                 Agency
                                 Municipal Environmental Researc
                                 Laboratory
                                 Cincinnati OH 45268
                                 Research and Development
                                 EPA-600/S2-81-097  July 1981
Project  Summary
                                Compatibility of  Source
                                Separation  and  Mixed-Waste
                                Processing  for  Resource
                                Recovery

                                Louis Soldano, Stephen C. James, and Charles Miller
                                  This   report  evaluates  whether
                                 source separation and  mixed-waste
                                 processing of municipal solid waste
                                 are  compatible  approaches  for
                                 recovery of materials and energy in the
                                 same community or region. Existing
                                 source  separation programs and
                                 mixed-waste   processing   facilities
                                 were analyzed  to develop typical
                                 options for assessment. Among the
                                 issues  addressed are  changes  in
                                 production of useful energy from a
                                 mixed-waste processing facility; air
                                 and  water pollution; residual  solid
                                 waste; employment; operator profit-
                                 ability;  total solid waste  collection
                                 costs;  and quantities  of  recycled
                                 materials.
                                  This Project Summary was develop-
                                 ed by EPA's Municipal Environmental
                                 Research Laboratory, Cincinnati, OH,
                                 to announce hey findings  of the
                                 research project which is fully docu-
                                 mented in a separate report of the
                                 same title (see Project Report ordering
                                 information at back).
                                 Introduction
                                  Are source separation and mixed-
                                 waste processing (MWP) of municipal
                                 solid wastes compatible approaches for
                                 recovery of materials and energy in the
                                 same community  or  region?  With
                                 source  separation,  salable materials
                                 (currently  aluminum, ferrous  metals,
                                 paper, and glass) are segregated from
                                 wastes at the point of discard for collec-
                                 tion  and  processing.  With  MWP,
                                 collected, mixed municipal wastes are
                                 centrally processed to convert the mixed
                                 wastes into energy and, if possible, to
                                 separate recyclable material. The basic
                                 difference between the two approaches
                                 is that source separation requires the
                                 separation  of wastes by the house-
                                 holder whereas MWP relies on machin-
                                 ery.
                                   Conflicts may arise between the two
                                 methods, however. Both may overlap in
                                 recovering  a single material from the
                                 waste stream  Supporters of source
                                 separation claim to recover the highest
                                 economic value, operators  of MWP
                                 facilities claim that separation of certain
                                 materials reduces the energy content of
                                 the solid waste and causes financial
                                 loss  to  plants  that require  a  fixed
                                 amount of waste to break even Mutual
                                 benefits  can be seen  where source
                                 separation  allows a larger amount of
                                 waste to be processed and increases
                                 equipment  life by  reducing abrasive
                                 materials. Conflicts may be the result of
                                 poor coordination rather than inherent
                                 conflicts
                                 Procedure
                                  Resource recovery was analyzed from
                                 the viewpoint of the mixed-waste plant
                                 operator, the  municipality,  and  the

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nation.  For  each  viewpoint, specific
issues that would be most important are
identified—energy materials conserva-
tion, environmental impacts, economic
impacts,  and  institutional/technical
impacts. This assessment was conduc-
ted for a hypothetical community with
solid  waste  data  equal  to  national
averages.
  Scenarios were based on five source
separation   options:   high-efficiency
multi-material recovery, low-efficiency
multi-material recovery, high-efficiency
newsprint   recovery,   low-efficiency
newsprint recovery, and beverage con-
tainer recovery.
  The following MWP alternatives and
possible combinations were addressed:
unprocessed  combined waterwall
combustion   and  ferrous  recovery
(UWCG); combined processed water-
wall combustion and ferrous recovery
(PWCF); refuse-derived fuel and ferrous
recovery (RDFF), and modular incinera-
tion without ferrous recovery (Ml). MWP
facilities options  were a fixed capacity
plant, a variable-sized plant with a fixed
service area, and a fixed capacity plant
with an expandable service area.
  The  hypothetical   community,
Baselyn,  has  approximately 100,000
people in a major metropolitan  area
producing 200 tons of solid waste per
day. The city's sanitation department
collects  solid   waste  from  all
households.  There  is  a  materials
processor who  buys  newspaper for
$30/ton, corrugated paper for $60/ton,
high-grade  paper  for  $70/ton, and
mixed glass and cans for $10/ton.
  For a "Fixed Service Area" of five
communities   like  Baselyn producing
1,000  tons/day  of waste, it may  be
economical  to reduce  plant size  or
collect waste from an outside area to
make up for reduction in waste because
of  source  separation.   For  "Variable
Plant Size,"  it is assumed that the
service area generates  1,000 tons/day
of waste but  alters the  plant size to
correspond to the waste remaining after
source separation.
  At  present, the source  separation
programs discussed for Baselyn recover
as  much as  5 percent of the waste
although as much as 10 percent can be
recovered. The reason  for this gap  is
that the waste generator has few incen-
tives to recycle materials because the
market prices fluctuate widely.
  Six common methods of source sepa-
ration are recycling centers, separation
of office paper, separation of corrugated
paper, separate collection of newsprint
and other paper, separate collection of
various materials, and beverage con-
tainer deposits.
  Although the value to large commer-
cial establishments of separating high-
grade office paper varies, it does have
good prospects for being  economically
feasible  Recovery rates for separated
corrugated paper are high because  of
ease of physical separation and because
recovery reduces mixed-waste collec-
tion  costs to commercial  establish-
ments. Separate collection of newsprint
and  other  paper  depends   on
participating   residents  who  place
newsprint at the  curbside in separate
containers.  Many of these programs
have  been  well received.  Separate
collection of various materials is less
common than single material programs
because of the burden of separating and
storing several different materials until
collection  day.   Beverage  container
deposits, including mandatory deposit
systems, place  responsibility  on  the
resident and can achieve recovery rates
as high as 90 percent. Each of the above
options, except recycling  centers, was
evaluated for Baselyn.
Source Separation Options
  For  high-efficiency  multi-material
recovery,  ordinances  required  resi-
dents to separate their waste into mixed
paper, clear glass and cans, mixedglass
and  cans,  and  remaining  waste;
scavenging of separated materials was
prohibited.  This option cost Baselyn
$982/day but  provided  revenues of
$546/day.  Eliminating 35.1  tons of
waste  reduced  landfill disposal  costs
from $8,890 to $7,330/day. If MWP
was  used,  costs were reduced from
$7,770  to  $6,406/day. Baselyn was
contractually required  to  supply the
MWP  operator  with  all  remaining
wastes.
  This   source   separation   program
extended the 20-year life of the county's
landfill by 3.6 years, lowered pollution
emissions  during  the   production
process, and slowed resource depletion.
  Low-efficiency multi-material
recovery is similar to the  case above
except  that  participation  is  voluntary
and there is no program for recovery of
office or corrugated paper wastes. In
this  option,  residents  were asked to
separate wastes into only three com-
ponents—mixed papers, mixed bottles
and  cans, and  remaining  waste. The
cost  of the source separation program
was  $513/day and  revenues  were
$303/day. The source separation pro-
gram  reduced  total  disposal cost by
$394/day  with  landfill  and  by
$322/day with MWP. Because Baselyn
had  no ordinance to enforce source
separation by residents,  the city and
intermediate processors were reluctant
to enter into any long-term contract.
  As in the first case, the county's land-
fill life was extended, but for only a little
more than a year. This option had little
effect  on the  groundwater  pollution
from the landfill and  only small reduc-
tions in pollution emissions for MWP.
  Two other options are high- and low-
efficiency  newsprint  recovery—
mandatory   and voluntary.  The
mandatory  program  resulted in a 60
percent recovery;  the  voluntary  pro-
gram,  20 percent. The high-recovery
program cost  $503/day  with  total
revenues of  $270/day.  Net disposal
cost was reduced $167/day for landfill
and $117/day for the  MWP plant. In low
recovery,  there  are  revenues of
$90/day. In addition to the advantage of
initial simplicity,  the most  important
effect of these programs is a slight
reduction in  landfill requirements.
  Beverage container recovery resulted
from state legislation rather than local
initiative. The program was operated by
the private sector, and waste reduction
was approximately 11.8 tons/day. This
recovery provided a net  energy of
102 X  109 joules/day. The mandatory
deposit option would extend landfill life
slightly but would greatly reduce road-
side litter.

Mixed-Waste Processing
Alternatives
  MWP energy can  be  recovered as
electricity, hot water or steam, or fuel.
Inorganic materials usually recovered
include ferrous metals,  glass  cullet,
aluminum,   and  nonferrous  metals.
Organic  materials recovered  can be
converted to compost, animal feed, or
chemical industry feedstocks.
  Unprocessed  combined   waterwall
combustion   and  ferrous   recovery
(UWCF) consists  of  mass  burning of
collected mixed waste in a thick bed on a
moving  grate  in a waterwall furnace.
The  ash is  quenched  before passing
over  a  magnetic separator,  where
ferrous  material is recovered and the
residue is sent to a landfill.
  Combined  processed  waterwall
combustion   and  ferrous   recovery
(PWCF) is the same  as UWCF  except
that the waste is shredded and sepa-^

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 rated into light and heavy fractions. The
 light fraction, a higher quality fuel than
 combined  waste, is burned. The heavy
 fraction is passed through a magnetic
 separator  and the residue is sent to a
 landfill. More waste can be handled this
 way than in  a UWCF.
   Refuse-derived fuel production and
 ferrous recovery (RDFF)  is similar to
 PWCF  except that the light fraction is
 processed into a fuel than can be used
 on or off site.
   Modular incinerators without ferrous
 recovery (Ml) can be batch type or
 continuous feed type. Since the typical
 size is  less than 50 tons/day, over 20
 units would be required to handle 1,000
 tons/day.
 Areas of Concern

 Energy
   An analysis of the source separation
 options used in Baselyn  showed  that
 variations of the BTU content resulting
 from source separation to be small and
 well  within  the  range  of variation
 expected  in raw municipal waste. For a
 fixed service area, source  separation
 reduces  both  the percent and total
 amount  of BTU recovery. For an ex-
 panded area, the total BTU recovery for
 each waste processing option is propor-
 tional to the BTU content/pound of the
 MWP stream.
 Environmental Impacts
   Environmental issues are emissions
 to air and water pollution from landfills.
 This  analysis  assumed  that  source
 separation and ferrous recovery were
 not  contaminated. Calculations  were
 based  on  1,000  tons/day  of  mixed
 waste.
  Although air emissions for each type
 of facility must be made on site-specific
 bases, emissions for each combination
 of  options are reported.  In general,
 paniculate  emissions  were  high
 enough  to present potentially  signifi-
 cant problems for all combined alterna-
 tives involving  MWP facilities.
  Residuals to  landfills for  each option
 were reported; the separation  options
 extended the life  of the landfill. Low
 newsprint  option  extended  it  1.5
 percent, and  high  multi-material sepa-
 ration extended it 1 7.6 percent. Greater
 extensions, up to 86.3 percent, can be
 attained by coupling source separation
.with MWP alternatives.
   The magnitude of water  pollution
 indicative  of  the  amount of  water
 discharged  from  the   facility  was
 reported.   Source  separation  alone
 caused few  changes  in  the  major
 environmental problems  of  landfills,
 i.e.,   pollution  of  surface  and
 groundwater  resulting from  leaching.
 MWP residuals created less leachate so
 that problem was greatly reduced.
   Considering the pollution to air and
 water, no  MWP  alternative is clearly
 superior.
 Economic Impacts
  Typical contract provisions between
 operators of MWP plants and munici-
 palities include long terms, guaranteed
 tonnages, guaranteed payment, estab-
 lished fees,  and adjustments to fees. In
 considering   the  economics  of  MWP
 facilities, the quality and quantity of the
 source  separation option will change
 revenues and cause higher costs per ton
 because of  plant under-utilization. In
 the  expanded service area,  the only
 source  separation  scheme  that  has
 more than a minor effect on processing
 costs is  the  removal of beverage con-
 tainers.  Removing  glass  and metals
 reduces  processing costs.
  The effects of source separation and
 MWP are also considered in overall
 employment,  railroad  freight   rates,
 influence on local decisions, savings on
 solid  waste disposal   costs,  and
 reduction in fuel import needs.


 Viewpoints

 The Plant Operator's
 Viewpoint
  The operator of a MWP facility has the
 objectives of receiving enough process-
 able  waste, recovering  the cost  of
 operation, marketing, and realizing a
 profit. The   operator's  concern   with
 source separation is its effect on the
 quantity and quality of waste sent to the
 MWP plant.
  For the operator,  source separation
 offers both potential risks and benefits.
 Risks include reduction  in supply  of
 waste, lower profits, and difficulties in
 financing the plant. Potential benefits
 are  lower maintenance costs  when
 unwanted materials  are  removed and
 the  possibility of securing  additional
quantities of waste for the plant. One
problem with opening a MWP facility is
that is may force local entrepreneurs to
lose their source of supply and cease
operations Source separation then be-
comes a part of the issue of "flow con-
trol," i.e., the ownership of wastes and
the legal rights of political jurisdictions
to specify where and how their wastes
are  disposed   MWP  operators  must
address the issues of reliability of supply,
profitability, cost of private  financing,
and whether source  separation will
inhibit  recycled materials purchasers
from committing themselves.
 The Municipal Viewpoint
  Municipal officials seek to dispose of
the community's solid waste in the most
economical and environ mentally accep-
table manner possible. The energy used
in collecting and transporting source
separated  materials  and  remaining
mixed wastes is a relatively small frac-
tion of the energy available in the mixed
waste. Use of source separation options
reduces  emissions from  trucks and
landfill  requirements.   Either source
separation  or   MWP  may  require
municipal  actions  with   significant
financial,  legal,  employment, tax, and
political implications. The primary issue
from the  municipal standpoint is the
effect  of  source  separation  on the
economics of collection, transportation,
and disposal of  mixed solid waste
 The National Viewpoint
  From  the   national  viewpoint,
 interests in resource recovery include
 reducing fuel imports, conserving valu-
 able material resources, and improving
 environmental  quality.  The  national
 environmental  issues are  reduction of
 the amount of waste and provisions for
 proper solid waste disposal. Because
 landfill sites are becoming more difficult
 to obtain and the regulations governing
 them are becoming more stringent, any
 action  reducing landfill requirements
 should  be  considered.  Pollution
 occasioned by coal mining, processing,
 and transporting will be eliminated in
 situations where MWP energy recovery
 is substituted.
Conclusion
  With  proper  planning, there is no
inherent incompatibility in any combi-
nation of source separation options and
MWP alternatives. As a matter of fact,
analysis  showed  that  combining  any
source separation option with any MWP
 > US GOVERNMENT PRINTING OFFICE 1981 -757-01Z/7ZZO

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alternative  will  result in positive or
neutral impacts.  In all cases, combina-
tions  are available  that  result  in a
greater net benefit than implementing
any one separately.
  The full report was submitted in ful-
fillment of Contract No. 68-02-2645 by
Gilbert Associates, Inc., Resource Plan-
ning Associates, and Crystal Planning
and Communications,  Inc., under  the
sponsorship of the U.S. Environmental
Protection Agency.
This Project Summary was authored by Louis Saldano, who is with the Munici-
  pal Environmental Research Laboratory, and Stephen James and Charles
  Miller, who are also the EPA Project Officers (see below).
The complete report, entitled "Compatibility of Source Separation and Mixed-
  Waste Processing for Resource Recovery," was authored by M. G. Klett, W. H.
  Fischer, B. N. Murthy,  H. H  Fiedler, L M. O/iva, and R Crystal
The above report (Order No. PBS 1-213 480, Cost. $ 15.50, subject to change) will
  be avaiiab/e only from:
        National Technical Information Service
        5285 Port Royal Road
        Springfield, VA 22161
        Telephone. 703-487-4650
EPA Project Officer Stephen James can be contacted at:
        Municipal Environmental Research Laboratory
        U. S. Environmental Protection Agency
        Cincinnati, OH 45268
EPA Project Officer Charles Miller can be contacted at:
        Resource Recovery Branch
        Office of Solid  Waste
        U S. Environmental Protection Agency
        Washington, DC 20460
United States Center for Environmental Research
Environmental Protection Information
Agency Cincinnati OH 45268

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 United States
 Environmental Protection
 Agency
 Environmental Sciences Research
 Laboratory
 Research Triangle Park NC 2771 1
 Research and Development
 EPA-600/S2-81-096  Aug 1981
 Project  Summary
 Modification  of  Optical
 Instrument  for  In-Stack
 Monitoring  of  Respirable
 Particle  Size
 A. L Wertheimer
  A light scattering instrument for in-
 situ measurements of participates in
 the 0.2 to 20 micrometer diameter
 size range is described, and field test
 results are presented. The instrument
 is a modified version of a prototype
 built during a prior EPA contract.
 Number 68-02-2447. The upper limit
 of the size response has been extended
 from 10 to 20 micrometers, and several
 component and  packaging changes
 have been incorporated to make the
 unit more suited to  stack paniculate
 survey applications. Low forward
 angle and 90° polarization dependent
 scattering is employed to make the
 measurements.
  The completed instrument was tested
 at a coal-fired electric power generat-
 ing facility. During the test a cascade
 impactor was used as a referee device
 and both instruments were run side by
 side in the outlet duct of the electro-
 static precipitator.

  The results show an excellent cor-
 relation between the two instruments
with regard to the identification of a
 1//m diameter peak in the particle size
distribution. A second peak around 20
fjm was defined by the optical instru-
ment,  but could  not conclusively  be
confirmed through the impactor data.
The optical instrument handled well
during the field test and was delivered
to EPA for additional testing.
  This Project Summary was devel-
oped by EPA's Environmental Sciences
Research Laboratory, Research Tri-
angle Park, NC, to announce key
findings of the research project that is
fully documented in a separate report
of the same title (see Project Report
ordering information at back).

Introduction
  A prototype real-time in-situ monitor
was developed and constructed on EPA
Contract 68-02-2447 to measure particle
size distribution of respirable particles
in the 0 2 to 10 /urn range. The purpose
of this project was to add a channel to
cover the  15 (jrr\ size range so  as to
include the upper cut-off of the inhalable
particulate emissions from stationary
sources.
  The  addition of the large particle
channel required a series of changes in
the optical and electronic assemblies of
the original instrument. In the process
of incorporating  these changes,the
latest available components were se-
lected and packaging improvements
were made, resulting in an instrument
optimally suited for survey work and
stack paniculate  analyses. The new
instrument measures the size distribu-
tion in the 0.2 to 20 /um range in five size
fractions, using a low power helium
neon laser light source
 The  modified prototype instrument
was tested at a coal-fired electric gen-

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erating plant. Referee measurements
were made with a cascade impactor.
Both instruments reported a strong
peak in particle size around one /jm in
diameter.

Procedure

Principles of Operation
  The instrument was designed by
using simple diffraction theory for the
low angle forward scattered light, and
rigorous Mie theory for the light scattered
at 90° to the probe beam. By adding high
angle scattering capabilities, the use of
light scattering for particle analysis can
be extended to the sub-micrometer size
range.
  The stack particulate monitor mea-
sures the light scattered by particles
passing through a 2.5 cm by 36 cm slot
at the end of a  152 cm (5 foot) long
probe. The light source is a 2 milliwatt
helium neon laser, which  emits a co-
herent beam at 0.6328 //meters. The
scattered light signals are proportional
to the volumes of particulate  material
present in each of five size fractions. Six
scattered light  readings are taken at
precisely determined angles. The light
signals are acquired through fiber optic
cables and transmitted to detectors
located in the transceiver. A digital
microprocessor calculates a five chan-
nel, volume-by-size histogram, covering
the size range from 0.2 /urn to 20 /urn.


Modification of the Prototype
  Modification of the original instru-
ment to add a 1 5/um channel involved a
number of significant changes. When
appropriate, these changes were made
so as to accommodate improvements
suggested from field trial experience
with the first unit. The pertinent aspects
of the new design are discussed in the
following  paragraphs.
  The xenon arc source was replaced by
a low power (2 milliwatt) helium-neon
laser, which provides better collimation
of the source, and eliminates a trouble-
some electrical transient starting prob-
lem.  A slightly larger collection lens
system was designed to accommodate a
wider range of forward scattering angles.
However, the 90°  collection system
used in the earlier unit remains the
same.
  A beam alignment sensor was added
to the tip of the probe to  monitor any
thermally induced shifts. Through ports
accessible from the rear of the probe,
the beam can be aligned in or out of the
stack by maximizing the reading on a
meter adjacent to the adjustment ports.
  A Z-80 microprocessor  system re-
placed  the original 8008 based elec-
tronics. The new system allowed for
rapid and efficient implementation of
the hardware  and software changes
required in modifying the unit The new
electronics is much more compact than
the earlier  version, and is combined
with a small digital printer in a 20 pound
transportable electronics console. A
second, smaller box, contains the elec-
tronics power  supply,  packaged sepa-
rately to avoid heat  build-up  on  the
control console box.
  A summary of operational character-
istics of the prototype is shown in Table
1. The measurement time can be set by
the user and ranges from 5 seconds to
12 minutes. Immediately following the
data collection, the size distribution is
printed out at the console.


Calibration
  The calibration process involved
several steps and used a variety of
materials. To properly fill the sample slot
region under operating conditions sim-
ulating a flowing gas stream, an aerosol
test chamber  was constructed in the
laboratory
  The  major  steps of  the calibration
process are outlined here.
  (1) During assembly, the light collect-
     ing apertures were  checked for
     alignment and adjusted to insure
     that the correct angles were being
     measured
 • (2) Di-octyl phthalate (OOP), a trans-
     parent  liquid with an index of
     1.49,  was dispersed  as a droplet
     suspension in  the aerosol  test
     chamber by a Phoenix Precision
     Aerosol Generator. This created a
     well-controlled size and loading of
     particles in the 0.2 to 3 fjm  size
     range From the measured signal
     levels and knowledge of the load-
     ings,  detector gain adjustments
     were made to accommodate a
     uniform distribution of particles at
     40 parts per billion.
  (3) The collection geometry and fiber
     transmission product at each
     angle was determined by measur-
     ing fresh, filtered cigarette smoke.
     Because the  majority of the par-
     ticulate volume is well below one
     fjm  in   diameter,  the forward
     scattering pattern does not change
     with  particle size. A correction
     constant is thus defined for each
     scattering angle,  based  on t
     difference between scattered lighi
     strengths observed and those
     predicted by theory.
Results

Laboratory Tests
  As a check for consistency, the instru-
ment was then used to measure the
aerosol distributions employed to cali-
brate it Figure 1  shows the  filtered
cigarette smoke distribution, indicating
a large percentage of the material in the
0.3 /jm  size channel, while Figure 2
shows the measured and manufacturer's
specifications for  the OOP aerosol
suspension. In both cases, agreement
between expectation and observation is
quite good.
  To further check the performance and
calibration, two other materials were
run, burning red phosphorous, and solid
glass  spheres. The red phosphorous is
used for tactical smoke screens, but no
referee data was available. The instru-
ment  readings indicated roughly equal
amounts of material in the 0.3  and 1 0
/jm size channels.  This is  consistent
with its intended tactical use since par-
ticles in this size range are the most
efficient scatters per unit volume and
thus provide good obstruction.
  The solid glass spheres, from Potters
Industries, Inc.,  were  used to check
performance of the larger size channels.
The spheres are specified as "3 to 10
micron" size, but no additional data was
provided or available.  No material  is
reported in the 0.3 fjm channel, as
expected, and most of the material  is in
the 3.5 or 7 5 fjm region. The material
reported in the 15 fjm channel may be
caused by clumping of the beads due to
electrostatic charges introduced in the
suspension process. Microscopic exam-
ination  of a  bead  sample collected
during the test confirmed this, showing
occasional clumping.

Field Test Performance
  During July, 1980,  the  prototype
instrument was tested at an east coast
coal-fired electric power generating
station. L&N personnel  used the proto-
type instrument to measure particle size
distribution m a  duct  leading to the
smoke stack. Personnel from Northrop
Services, Inc., Environmental Science
(NSI-ES),  participated in the tests,
taking data with  a cascade impactor,
and provided the necessary data analysis

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 able 1.    Operational Characteristics of Stack Paniculate Monitor
 Size Range (Particle Diameter)

 Size Discrimination
 Mode of Operation


 Loading Range



 Measurement Time



 Duct Velocity

 Duct Temperature

 Instrument Temperature

 Power Requirements


 Probe Dimensions


 Sample Slot Dimensions

 Transceiver-Probe Assembly


 Control Console


 Electronics Power Supply


 Blower


 Probe Material
    0.2 to 20.0 fjm

    Five volume fractions with centers at 0.3, 1,0,
    3.5, 7.5, 15 fjm

    Low angle forward scattering and 90°
    polarization dependent scattering

    0.01 to 1.0 grams of material/meter3 (.023
    to 2.3 grams/ft3) or 4 to 400 parts/billion by
    volume (with s.g. of 2.5}

    Signal integration time selectable from 5
    seconds to 12 minutes (including a 6-minute
    position)

    1.5 to 18 meters/second (5-60 feet/second)

    260° C maximum (500° Fj

    2° Cto43° C(35to  110° Fj

    One 20A, 115 volt, 60 Hz outlet

Physical Specifications

    152 cm long (60 inches) by 9 cm diameter
    (3'/4 inches)

    25 x 36 cm (1 x 14 inches)

    203 x 25 x 25 cm. 31.8 kg (80 x  10 x 10 inches,
    70 pounds)

    38 x 41 x 25 cm, 9.1 kg (15 x 16 x 10 inches,
    20 pounds)

    23 x 41 x 25 cm, 6.4 kg (9 x 16 x 10 inches,
    14 pounds)

    74 x 48 x 43 cm, 22.7 kg (29 x 19 x 17 inches,
    50 pounds)

    Type 316 Stainless Steel (except for optical
    components)
for that method. Six separate data sets
were collected over two days. One set of
data from each day is presented here.
  All testing was performed at the
outlet of the electrostatic precipitators
and  prior to the final exhaust fan. The
testing section was a vertical flow duct,
approximately 32  1/2 ft. wide by 7 ft.
deep. Sampling ports are located hori-
zontally across the wide side of the duct.
Each port is a 6-mch diameter flanged
pipe, approximately 14  in. long. Two
adjacent ports were selected as test
points A summary of the stack condi-
tions appears in Table 2.
  All aerodynamic particulate sizing
was performed using a  University of
Washington Mark III Cascade Impactor
and necessary support equipment. Prior
to actual  source testing, all  in-stack
atmospheric measurements necessary
for isokinetic and other calculations
             were recorded. Velocity head and stack
             differential pressure measurements
             were peformed using a type "S" pilot.
             In-stack temperatures  were measured
             using a thermocouple system attached
             to the end of the pitot tube. Velocity
             profile measurements were made up to
             4.5 ft. into the duct at both test ports,
             with the impactor sampling conducted
             at the point of both average velocity and
             close proximity to the optical instrument.
             The point used for sampling was ap-
             proximately the mid-point of the duct or
             4 ft  from the lip of the port flange.
              The  impactors were preheated to
             stack temperature before sampling to
             avoid moisture condensation within the
             impactor body. The duration of each test
             was varied according to the stack opacity,
             knowledge thatthiscoal unitwaswithm
             particulate emissions  standards, and
             the visual  inspection of the previous
    80-

    70




    50-

    40-

    30-

    20-

    10-
             .3  1.0  35  75   15
                    ^
Figure 1.
Calibration   run
cigarette smoke
                              using
impactor test. Sample runs varied from
20 to 40 minutes in length.
  Several hours were required to make
the preliminary measurements before
the impactors were inserted.
  The prototype optical particle size
monitor was prepared within approxi-
mately one hour. All electrical cables
were connected and the  instrument
was turned on to warm-up the electron-
ics. The  optical  alignment of the unit
was adjusted using the external meter.
The stack velocity,  measured for the
impactor runs,  was used to  set the
purge flow rate on the blower. To facili-
tate insertion and removal from the
stack during the tests, a suspension rail
designed and built previously  for this
unit by NSI-ES was erected. A typical
sample run lasted 6 minutes, and sev-
eral runs were made during the impactor
sample collection period.
  On  the first sampling day the boiler
unit was operating at maximum output.
On the second day, the  boiler was
operating at reduced output, and the
particulate  emissions were distinctly
lower, dropping from around 0.02g/Nm3
the first day, to 0.007g/Nm3 the second,
as measured by the impactor.
  Results for both optical  and inertial
instruments are shown in Figures 3 and
4, plotted as histograms of volume
fraction per unit  log  interval of  particle-
size The optical data  in each figure are
indicated by the cross hatched histogram,
while  the impactor data are shown  as
the heavier outlined histogram. Varia-
tions in the  individual.channel widths

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30-,
SO-
70-

60-
| 50-
40"
§?
30-
20-
10-












	












Measured
	
Manufacturer's
Spec.



— -,
                                        Table 2.    Stack Conditions During Field Test
Figure 2.
            3   1.0  35 7.5   15
Calibration using dibutyl
phthalate  aerosol  from
Phoenix generator
are due to the different principles
involved in measuring the  particle
distribution
  The impactor data, provided by NSI-
ES, were derived by plate weighings and
computer assisted data reduction. A
material density of 2.5g/cm3  was as-
sumed, and the channel edges were
based on the aerodynamic  separation
properties of the individual stages of the
impactor.
  During each impactor run, continuous
optical data measurements were made.
The histograms shown are compiled
from the time weighted average of the
sequential optical data, which  involved
from 5 to 8 optical  runs, depending on
the length of  the  impactor run.  The
boundaries of the optical histogram are
determined by the instrumental response,
as calculated from scattering theory.

Discussion
  The optical and inertial measurements
agreed in some significant respects. In
all runs both instruments reported a
significant size fraction to  be around
one fjm in diameter with, in most cases,
substantial reductions in the amount of
material above the one /urn size.  The
optical instrument consistently indi-
cated a good  deal of material in its
largest size channel, which made the
distribution appear  bimodal. This could
not be definitely  confirmed by  the
impactor data  available, although im-
pactor runs from some tests show a
                                          Stack gas velocity:
                                          Stack gas temperature:
                                          Gas pressure.
                                          Direct/on of flow:
                                                                 45 to 50 feet/second
                                                                 230 to 300° F
                                                                 -2 inches of Hg
                                                                 Vertical downward
leveling off of the distribution, and run 4
does indicate a secondary peak in its
largest particle channel
  The general agreement between the
two methods is good. The size response
question could well be resolved through
further testing at other  sites. There
were some relatively minor technical
problems, but none that should prevent
the optical instrument from being used
in other field tests. At the conclusion of
this test, the prototype stack paniculate
monitor and its associated  equipment
were turned over to the EPA.

Conclusions and
Recommendations
  The primary goal of this work was to
modify and test a prototype optical stack
particulate monitor by the addition  of a
channel responding to particles  in the
15 /jm size range. This was successfully
accomplished  Tests m the laboratory
showed results  that agreed with ex-
pected size distributions of several
                              40-
sample materials which were in the 0.2
to 20 /urn size range of the instrument.
The field tests, conducted at a coal fired
electric utility plant, provided size distri-
bution data which were in excellent
agreement with results reported by a
referee inertial  impactor. An additional
advantage with the optical instrument is
that size distribution data are computed
and  displayed  immediately upon the
conclusion of  the signal  collection
sequence.
  A secondary goal of this project was to
improve the reliability and portability of
the instrument to make it more suitable
for stack survey  work. The modified
prototype  unit  is lighter  and smaller
than the original, and the operational
improvements, such as ease of align-
ment  and reliability of operation, were
demonstrated during the field trial.
  There may be some value in develop-
ing an on-site technique to provide the
opera tor with a quick means of checking
the calibration  of  the  unit Although
                                                Run No. 1
                                                Impactor
                                                Optical Sizer
                                       .2
                              1       2         5

                                Diameter, D(/jm)
                10     20
                            Figure 3.
             Particle size vs volumetric concentration distribution during Day 1 of
             the field test

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     50-i
     0,~ ,
     30-
  O

 <  20-
     10-
                                               Run No. 4
                                               Impactor
                                               Optical Sizer
                                    1       2

                                     Diameter, D(/jm)
20
 Figure 4.     Particle size vs. volumetric concentration distribution during Day 2 of
              the field test

 there are no moving parts in the proto-
 type which would affect the calibration,
 some form of indicating calibration
 status is desirable.
  Another area for future consideration
 is modification of the electronics to
 optimize the gain  for  loadings at or
 below the originally specified range of
 0.01 toO.1 grams/meter3.Thiscould be
 done by changing the feedback resistors
 at the detector board  and trimming the
 electrical offsets to lower values.
  In its present form, however, this type
of instrument should prove to be  very
useful for field survey work for analysis
of size distributions from stationary
sources. Recommendations for  future
work involve  additional field trials at
 sites with different types of fuel, clean-
up devices,  and loading conditions.  To
gain confidence in  this type of  instru-
mentation, measurements with referee
sizing  instruments should be taken in
parallel
  i US GOVERNMENT PRINTING OFFICE 1W1 -757-01Z/728Z

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United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
Postage and
Fees Paid
Environmental
Protection
Agency
EPA 335
Official Business
Penalty for Private Use $300
                 3  uF .". t'-rif IK  ,  S 11- r F," i'
                :/>r'.(_:   H   
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