United States
                   Environmental Protection
                   Agency
Hazardous Waste Engineering
Research Laboratory
Cincinnati OH 45268
                   Research and Development
EPA/600/S2-87/009  June 1987
SEPA         Project Summary
                   Field Assessment of Aerated
                   Lagoon  Emissions  and  Their
                   Control  Using an Inflated Dome

                   Thomas P. Nelson, Bart M. Eklund, and Robert G. Wetherold
                     The fate of volatile organic
                   compounds (VOC") in  an industrial
                   wastewater activated sludge system
                   was investigated through a four-day
                   sampling and analysis  program. The
                   system included an aerated  lagoon
                   which  is  covered by an Inflated
                   synthetic  dome. The  dome has a
                   carbon adsorption column to reduce
                   emissions of odorous organic
                   compounds. Samples  of air,  water
                   and sludge streams associated with
                   the  activated  sludge  system were
                   collected,  along with air  samples at
                   the  inlet and  outlet of the carbon
                   adsorber.  These were analyzed  to
                   determine the concentrations  of
                   individual  volatile   organic
                   constituents. The  effectiveness  of
                   the  dome and  carbon adsorber  in
                   reducing lagoon emissions of volatile
                   organic   compounds   was
                   investigated, as was the applicability
                   of  the  Thibodeaux-Parker-Heck
                   model to predicting emissions from
                   the covered aerated lagoon.
                   Approximate percentages of removal
                   of   VOCs  by biodegradation,
                   adsorption and volatilization  in the
                   aerated lagoon were determined.
                     This  Project  Summary  was
                   developed by EPA's Hazardous Waste
                   Engineering Research Laboratory,
                   Cincinnati, OH, to announce key
                   findings of the  research project that
                   is fully  documented in a separate
                      As  used in  this study the term
                   volatile organic compound  (VOC)
                   applies to compounds which can be
                   extracted from  liquid wastes by a
                   purge and trap method
 report of the same title (see Project
 Report ordering information at back).

 Introduction
   The Office of Air Quality Planning and
 Standards  (OAQPS)  of  the  U.S.
 Environmental  Protection Agency is
 developing standards to control
 emissions  from hazardous  waste
 treatment, storage, and disposal facilities
 (TSDFs).  The purpose  of  these
 regulations  is to protect human health
 and the environment from impairment by
 emissions of volatile organic compounds
 (VOCs) and particulate matter.  The
 Hazardous Waste Engineering Research
 Laboratory   (HWERL)  has  the
 responsibility of  providing technical
 support  to  OAQPS in the area of
 atmospheric emissions  from  hazardous
 waste management. Part of the research
 in the HWERL program involves studying
 emission control techniques applicable to
 TSDFs.
   The objective of this project was to
 obtain  field  measurements of the
 effectiveness of emission controls for
 off-gases from an aerated  lagoon.
 Specifically, the three primary objectives
 of the lagoon enclosure testing were to:
 • measure the control efficiency of the
  activated carbon beds  which were used
  in the treatment of the off-gases from
  the lagoon;
 • measure the  overall  effectiveness of
  the  dome and carbon adsorption
  system in controlling lagoon emissions;
  and
 • determine the applicability of
  Thibodeaux's model to  predicting
  emission rates from  aerated
  impoundments.

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   As part of the  assessment of  lagoon
emissions  and  their  control,  an
approximate  mass  balance was
performed  around  the  lagoon  to
determine the fate of influent VOCs. Also,
the effectiveness of 55 gallon drums of
carbon used to control breathing  and
working losses in the waste pretreatment
area was  determined.
   The TSDF site chosen for this study is
the Upjohn  Fine  Chemicals facility in
North Haven, Connecticut. At this facility
Upjohn produces speciality chemicals as
intermediates for other Upjohn divisions
and for sale to other end users. At  the
time  of  this  sampling,  1984,  the
wastewater was being treated in a series
of processess  (naturalization, primary
clarification,  and activated  sludge) prior
to being discharged (see Figure 1).
   The site was chosen because of  the
emissions control system used at  Upjohn
to minimize  odor.This  system is  located
at the  aerated lagoon that is part of  the
activated  sludge system.  Control
consists  of  an  inflated dome  over  the
lagoon with  carbon adsorption beds to
remove odorous compounds  (primarily
orthochlorophenol) from  the exhaust
gases (Figure  2).  While   ortho-
chlorophenol is very  water soluble, but
not  highly  volatile,  the  facility
wastewaters do  contain aromatic  and
halogenated organic  compounds  which
are volatile.  The  dome  and carbon
adsorption system at Upjohn was studied
to determine its efficiency  in controlling
emissions of these volatile compounds.

Approach
   The  nonmethane  hydrocarbon
(NMHC) content of the dome bleed-off
gas was monitored at the inlet and outlet
to the dome's carbon  adsorption unit and
inside the dome using  on-site  total
hydrocarbon  and  gas  speciation
instrumentation. Canister samples  were
collected for  gas specification off-site.
Samples were also collected at the  inlet
and outlet  of  55 gallon  drum carbon
adsorption units at  the  vents to  the
wastewater treatment system neutralizer
tank. A screening of potential leak  points
around the dome was performed using a
portable hydrocarbon  analyzer.
   Liquid  and  sludge samples  were
collected at selected points around the
wastewater  treatment system. These
were  analyzed  for  total  NMHC content
and for major volatile organic species.
The resulting  data  were  used
determine the fate  of  volatile organi
entering the aerated  lagoon.
   The composition  data  of the aerati
lagoon  effluent were utilized  in  tl
Thibodeaux-Parker  Hwang  emissioi
model for aerated surface impoundmer
to predict emissions with the dome
place.

Findings

   The volatile organics identified  in tl
influent  stream to  the aerated  lagoi
were  classified as volatile  paraffii
(15%), aromatics (45%),  and  haloge
(40%). Major volatile compounds inclui
1,2-dichloroethane, benzene,  toluei
and chlorobenzene. The approxima
material  balance performed  around tl
aerated lagoon  indicated   th
approximately 60 weight percent (± 201
of the influent VOCs are volatilized  ai
exhausted from the  dome structure.  Tl
volatilized  organics are  primari
halogenated  organic   compounc
(e.g.,1,2-dichloroethane).  Twenty-eig
percent (±4%) of the influent VOCs a
discharged  from the  aerated  lagoo
These are predominately paraffins.
                                                                 Sludge    Sludge
                                     Clarifier
                                    Underflow
                                         Centrifuges

                                             FM
                   Caustic
                                                     Clarifier
                                                    Underflow
        Carbon
       Cannisters
   Process
  Wastewater
                                                                Aerated Lagoon/
                                                                Dome Structure
                                                                            Clarifier  (F-M
                                                                           Underflow
                                                                                     (ff/
                                                  I
                                             FM
                                                          Secondary
                                                          Clariliers
                                                                                                   Clarifier
                                                                                                   Overflow
                  -(FM
                    -^ To Municipal
                     Wastewater Syste
                       (Not Operating)
                                                                                               Wastes
                                                                                               to River
   Figure 1.    Wastewater treatment system.

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                                          Main Blower
                                        (Capable of up to
                                     20.000 CFM @ 1.5 W.CJ*
                                                                       NE Comer
                                                                        of Dome
                                                                        Dome
                                                                       Concrete
                                                                        Footing
                                                                                             Carbon Adsorber
                                                                                             Fan (3OOO CFM)
   Doorway
  with Blower
 (Under Positive
 Pressure with
   Respect to
Bubble Pressure)
Auxiliary
 Blower
(Propane-
Powered)
                         Propane Heater
                       for Winter Operation
                   (Capable of 2,500,000 Btu/hr)
                                                          (Open) (Closed)
                                                            Outside Air
                                                          Intake Dampers
        *Has been shimmed and current air flow rate is unknown.
  Figure 2.     Dome structure inflation fan and exhaust system.
   Due to the combined uncertainties in
measured influent, effluent and emission
rates, a large uncertainty was associated
with  estimating  VOC biodegradation by
difference. Biodegradation was the major
pathway for  aromatics  removal,
accounting  for 65  percent  (±20%)  of
aromatic  fate. However, the amounts of
paraffins  and  halogenated VOCs  that
were  removed by  biodegradation  were
smaller than the combined uncertainties
of the measurements  used to estimate
them.
   The  Monte  Carlo  simulation
uncertainty  analysis performed on  the
material  balances  showed   two
weaknesses  in the determination of the
fate of organic compounds in the aerated
lagoon.  First,  difficulties  with  the
extraction  of  volatile organics  from
wastewater  sludge  streams  led to an
uncertainty  of  ±50%  in  their  VOC
content.  Second,  there  was a large
uncertainty  (up  to  ±58%) in  emissions
measurements due  to the variability in
gas  composition  going through  the
carbon adsorber.
   The inflated dome is estimated by the
facility to have less than  a 0.14 m3/sec
(300 cfm) leakage  rate,  which is  low
compared to the purge  gas bleed-off
rate  of  1.4  m3/s  (3000  cfm).  A
                                 preliminary  screening  of  the dome
                                 structure indicated that the largest leaks
                                 were small in number and had very  low
                                 (<1 x 10-4 m3/s) flow rates.
                                   The carbon  adsorber on the dome
                                 exhaust provides virtually  no (<1%)
                                 VOC removal. This is primarily because
                                 the  extremely high (approximately   100
                                 percent) relative humidity in  the carbon
                                 adsorber inlet gas stream is  believed to
                                 interfere with the adsorption capability of
                                 the  carbon. The  activated carbon  bed
                                 system  was originally  designed  for
                                 control  of  water soluble odorous
                                 compounds,  and  Upjohn feels  that  the
                                 system  is  performing  this  function
                                 effectively.
                                   Fifty-five  gallon drums of activated
                                 carbon are  used on  vented emissions
                                 from the neutralizer  tanks and primary
                                 clarifier at the  TSDF. Testing  indicated
                                 that  these  drums work very  well in
                                 removing NMHC  emissions  in the  vent
                                 gas.  Removals  of over 99 percent were
                                 measured  for specific hydrocarbon
                                 compounds.
                                   Mathematical models  developed by
                                 Thibodeaux-Parker-Heck models  are
                                 inconsistent in  their  abilities to predict
                                 actual emission rates. Comparability of
                                 modeled and measured emission rates
                                 varied with compound. This appeared to
                                                    be  partially  due  to  a  significant
                                                    concentration  of  VOCs  in  the dome
                                                    atmosphere and due to the shallowness
                                                    of the lagoon,  which may have inhibited
                                                    complete mixing of wastewater and led to
                                                    nonuniform VOC  concentrations within
                                                    the  lagoon.  Also, the  inability  to
                                                    empirically  determine  key  model
                                                    variables  limits  the accuracy of  the
                                                    models.

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  Thomas P. Nelson, Bart M. Eklund, and Robert G. Wetherold are with Radian
  Corporation, Austin, TX 78766.
  Benjamin L Blaney is the EPA Project Officer (see below).
  The complete report,  entitled "Field Assessment of Aerated Lagoon Emissions
  and Their Control Using an Inflated Dome," (Order No. PB 87-145 9421 AS;
  Cost: $24.95, subject to change) will be available only from:
           National Technical Information Service
           5285 Port Royal Road
           Springfield, VA 22161
           Telephone:  703-487-4650
  The EPA Project Officer can be contacted at:
           Hazardous Waste Engineering Research Laboratory
           U.S. Environmental Protection Agency
           Cincinnati, OH 45268
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
Official Business
Penalty for Private Use $300

EPA/600/S2-87/009
         0000329   PS

         U  S  EHVIR  PROTECTION  AGENCY
         REGION 5 LIBRARY
         230  S  DEARBORN  STREET
         CHICAGO               IL   60604

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