PB88-180112
Control of Volatile Organic Contaminants in
Groundwater by In-Well Aeration
(U.S.) Environmental Protection Agency
Cincinnati, OH   ,    •  "
Mar  88

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Regional Center for Environmental Information
            US EPA Region III
               1650 Arch St.
           Philadelphia, PA 19103

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                                                                                PB88-180112
I
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                     '     '           '''        '"     '                      '
                              i: CONTROL OF VOLATILE ORGANIC  CONTAMINANTS
                               ' ":       •      -      TM   •          -   .-,.''
                             ----- :.--   -  •  ^_   •• :      IN    .-'.•-•-   .  •  •••    •
                             .-,;-'.'•;  . GROUNDWATER BY IN-WELL AERATION


                             ;
                                      .•-..       -    .
                                       '      Judith A. Coyle
                                          Harry J. Borchers, Jr.
                                        North Penn Water Authority
                                       Lansdale, Pennsylvania 19446
                                    .         .       .
                                            Richard J. Miltner
                                     Drinking Water Research Division
                                  Water Engineering Research Laboratory
                                          Cincinnati, Ohio 45268
                                     Cooperative Agreement  CR-S09758
                                              Project Officer
                                             Richard J. Miltner
                                      Drinking Water Research Division
                                  Water Engineering Research Laboratory
                                           Cincinnati, Ohio A526R
                                   WATRR F.NOINEKRING RESEARCH LABORATORY
                                     OFFICE OF RESEARCH AND  DEVELOPMENT
                                    U.S. ENVIROKMENTAL PROTECTION AGENCY
                                           'CINCINNATI, OHIO  45268
                                        REPRODUCED3Y
                                              INFORMATION SERVICE
                                           ..  SPRiNGFlELD.VA. 22161  .
                                                          •

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.•"':-.•'..--- -••'. '. TECHNICAL REPORT DATA . ;?.-.• .
•"-.-'••• ; ;• -'•'.. • (Kate rcid tnsirjc nous on the reverse before c ample tirtfj . ..'••'
1. REPORT NO. . . |2. ' . -
- EPA/600/2-88/020 I
4. TITLE AND SUBTITLE •- • ..
CONTROL OF VOLATILE ORGANIC CONTAMINANTS IN
.GRO'JNDWATER BY IN-WELL AERATION
' ' " ' ' .
7. ALJTiiORlS)
Judith A. Coyle, Harry J. Borchers, Jr., and
Richard J.-Miltner •- • .
?. PERFORMING ORGANIZATION NAME AN'D AODRESS
North Penn Water Authority -:•
200 N.. Chestnut Street . .
Lansdale, PA 19446 . . - '
>2. SPONSORING AGENCY NAME AND ADDRESS
Drinking Water Research Division
Water Engineering Research Laboratory
Office of Research and Development, U.S. EPA
Cincinnati, OH 45268
3. RECIPIENT'S ACCESSION NO.
PQSi- 1 to in
5. REPORT DATE
March 1988
5. PERFORMING ORGANIZATION CODE
8. PERFORMING ORGANIZATION F.EPCST NO.
10. PROGRA.V ELE.MEr.'T NO.
C104, BNC1A, Task 109 S
:i. CONTRACT/GRANT NO.
CR-809758
13. TYPE OF REPORT AND PERIOD COVERED
Final 2/8ฐ 2/ฐฃ
1ซ. SPGNS'ORTSi'CT ^Ge'dC'V CODE
EPA-600/14
.15. SUPPLEMENTARY NOTES , , . • • ..-
"% - ' " ' " . . • . - ' . '
16. ABSTRACT . . .
~v-At a 0.1 mgd well contaminated with several volatile organic compounds (VOCs) ,
principally trichloroethylene (TCE), several in-well aeration schemes were evaluated
as control technologies. The well was logged by the USCS to define possible zones
of VOC entry. A straddle packer and pump apparatus were utilized to isolate those
zones and define their yield and level of VOC concentration. The technical litera-
ture together with this knowledge of the well were used to design an air lift punp.
Operation of the air lift punp confirmed literature prediction of its low wire-to-
water efficiency. Removal of TCE did not exceed 65 percent. Mass transfer occurred
in the punp's eductor. Air lift pimping coupled with in-well diffused aeration
increased TCE removal to 78 percent. When in-well diffused aeration was used' with
an electric submersible punp, TCE removal averaged 83 percent. In the latter two
schemes, mass transfer occurred utilizing tho uell as a countercurrent stripper.
These technologies are limited by the volume of air that can he transferred to the
well (air-to-water ratios below 12:1) and the cost of compressing air under high
head. Thus, these technologies are not cost-effective compared to packed tower
aeration. They are, however, quickly put on-line, easv to operate, and can serve
as good short-term remedies while above-ground technologies are under design and
construction.
17. \ KEY WORDS A.VD DOCUMENT ANALYSIS
a. DESCRIPTORS b-IDENTIFIERS.'OPEN ENDED TE RMS
in-well aeration, air lift pumping,
diffused aeration, trichloroethylene,
vinyl chloride, cis-l,2-dichloroethylene,
well characterization
'.I. S:ฃT.=.!E'_'T!2N STAT-'"^"1" 19. SECURITY CLASS ITI:n K>;-""':
Unclassified
Release to Public so. SECURITY CLASS ,T/IMPซ.ซI
Unclassified
c. COSATi FiclJ/Cioup

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                                  DISCLAIMER
   =    The  Information In this document has  been funded wholly or  In part
   by  the United  States  Environmental  Protection  Agency under  assistance
   agreement  CR-809753  to the  North Penn Water  Authority.   It  has  been
   subject  to  the Agency's  peer  and administrative  review  and  has  been
   approved  for publication as an  EPA document.   Mention of trade nanes  or
   conmerctal products  does not constitute  endorsement  or reconnendatlon for
   use.   •   '•   ••       ' .  - • '   . •   '  -:.-•   ,.'-•'-           . •'   -.    .'•.••'•.-.•''

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       .  .       .
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                                                FOREWORD
                     The U.S.  Environmental  Protection Agency  Is charged by Congress with
                protecting the Nation's land,  air and water systems.  Under a mandate of
                national  environmental  laws,  the  egency  strives  to  formulate  and.
                Implement  actions  leading   to   a  compatible  balance  between  human
                activities and  the ability of natural   systems  to support  and nurture
                life.  The Clean Water Act, the  Safe Drinking  Water Act,  and the Toxics
                Substances Control Act are three  of the major congressional  Isws that
                provide the framework for restoring and maintaining the Integrity o* our
                Nation's water, for preserving and enhancing the water we drink, and for
                protecting the environment from toxic substances.   These laws direct the
                EPA to perform research to define our environmental  problems, measure the
                Impacts, and search for solutions.
                     The Water Engineering Research Laboratory  Is that component of EPA's
                Research and Development program  concerned with preventing, treating, and
                managing municipal  and  industrial  wastewater  discharges;  establishing
                practices to control  and  remove  contaminants  from drinking water and to
                prevent Its deterioration during storage and distribution; and assessing
                the nature  and controllability of  releases  of toxic  substances  to the
                air, water, and land from manufacturing processes and subsequent product
                uses.  This  publication  Is one  of  the products  of that  research and
                provides a vital ccmnunlcatlon link  between  the  researcher and the user
                corrmun I ty.
                     Under  the  Safe   Drinking   Water  Act,  the  EPA  will  regulate
                trlchloroethylene,  vinyl  chloride,  cls-l,2-dlchloroethylene  and  other
                volatile organic contaminants found  In  the  nation's groundwater.  While
                the EPA has  stipulated  that  granular  activated  carbon  adsoprtlon and
                packed tower  aerators  are "best available technologies"  for control of
                these contaminants In  drinking voter,  other technologies may be used.
                This   publication  reports  on   an  evaluation   of   In-well   aeration
                technologies.    Air  lift  pumping with and  without   In-well  diffused
                aeration, and In-well diffused aeration  coupled with electric submersible
                pumping were evaluated.  These technologies were not as cost-effective as
                packed tower aeration for long-term control  of these contaminants.  They
                will, however, provide  short-term control at  low capital cost while above
                ground, long-term technologies are under design and construction.
                                                    Francis T. Mayo, Director
                                                    Water Engineering Research Laboratory

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 '  '•:'••;   ..-..;••  .:•;.,.'-  ...    /    ABSTRACT          -~  "           •   .-•"•   ^ :./",•:.-.;.; v.^
 •  .-•  ' ;,.-•'-  '•• '  '  "':.-  '   '.:.   ..  ".   •'•"'.  • -'     ' '.  -   "   .       -   ". ' ;:'X;V,V ' •-"•.'"•'-'•-/•I
       .....,..,   ..   .    -  ^             ........        .     ^  .    _.   ... .-;,•-_.-..,  (.-J
      Several   In-well   aeration   schemes   were  evaluated  as  control               j
 technologies  at a   0.1  mgd well   contaminated with several, organic       ' •  '...-,. ^
 chemicals  (VOCs),   principally  trlchloroethylene (TCE).   The well  was          '     I
 logged by the U.S.G.S. to define possible zones of VOC  entry.  A straddle          •'   r^
 packer and pump apparatus were utilized to  Isolate thosa zones and define        •     ;  ?
 their yield and level  of VOC  concentration.  The  te-ihnlcal literature        •"'•''-.'..•'1
 together with this knowledge of the well were used to Design an air  lift            .-'  ;i
 pump.  Operation of the air lift pump confirmed the  literature prediction          .   -.^
 of  Its  low wire-to-water efficiency.   Removal  of TCI"  did  not exceed 65          -' ; .>
 percent.  Mass transfer occurred  In the pump's eductor.  Air  lift pumping           '-  .••
 coupled  with  In-well   diffused  aeration   Increased  TCE  removal  to 78               ;
 percent.   When  In-well diffused aeration was  used  with  an  electric          .     r'
 submersible  pump,  TCE  removal  averaged 83 percent.   In the latter two              5
 schemes, mass transfer occurred  utilizing  the well as a  countercurrent             :'^
 stripper.                              :   .                                           . ; ?'
      Ofl:-gases of  the  In-well  aeration process  were  tested  and  It was               '
 determined  that, depending on the raw  water  chemical  concentration, air               •
 pollution  discharge  permits  may  be  required  to  operate  an  In-well            :
 aeration treatment  system.   Dissolved oxygen and pH both   Increased with
 In-well    aeration   which   may   have   distribution   system  corrosion
 Implications.  Bacteriological testing was  Inconclusive.                           .  '   ;
      These  technologies are  limited  by the  volume of air  that  can be               ;
 transferred to the well  (air-to-water ratios  below 12:1) and the cost of            .   ]
 compressing  air under  high  head.   Thus,  these .technologies are  not               :
 cost-effective compared to  packed tower  aeration.   They  are,  however,               •:
 quickly  put  on-line,  easy to  operate,  and can "serve  as good short-term
 remedies   while   above-ground   technologies   are  under   design   and
 construction.                                                                        _-..-;
      This  report was submitted  In fulfillment of .cooperative agreement
 number  CR-809758  by  thซi North  Penn  Water Authority   under  the  partial               ,
 sponsorship  of the U.S. Environmental  Protection  Agency.   This report              •.„.
 covers  a period from February  19S2  to February 1986.  Field work was
 completed as of March 1985.                                              •           •'.•••/
                                    Iv

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; K-^'-v-'li.:U"Vv  "'/ .'./.'.'"'''"  .  CONTENTS     ,'-;   "V .  :;: .•;:••;/'-  '•••<'-. ••'• -'..v •'/-';.:;;-"-;

 Foreword	 Ill      ,     :    ,
 Abstract	...........;....  Iv. •• ;'         v^
 Figures	  vl       -    ' •.
 Tables	•..-..'.•..;......	  Ix      :-     v
 Abbreviations	   x   . .        . ...
 Acknowledgment	  xl       "    V - -.

      1.   Introduction	   1      -      .
   •   2. .  Conclusions	   %
 ,•  -.3.   ReconrnendatIons	   8    '.      .-  .-
      tf.   In-Well Aeration	   9
      5.   Well Characterization		'...I....  12           '  , .  |
     • o.   Experimental Design	  32
      7.   Prel Imlnary FootpSece Investigations	  ^2
      8.   Air Lift Pump Testing Without a Sparger	  61
      9.   Air Lift Pump Testing With a Sparger	  72                 ,,
     10.   Electric Pump Testing		  8*1,     |
     11.   Secondary Effects of In-Well Aeration	  93                 1
     12.   Cost Estimates	 101

 References	 103 .

 Appendices         .                                                                 j-|

      A.   Surrmary of Equations Used 	 106                F|
      B.   Gas Chrcmatographlc Conditions and Quality Control                 ,           ||
          Program	 108                ^
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:' •'••'•. ;..•-.'  '.""•••• •. :.:  ;  :;        FIGURES  '-.     '   ;.        'X.:-'' ••:".-

 Number      ;„    ;•   '        :..'.'           .-•  • . "-;'.     .    •.  .:   Page

 .  1      Diagram of Air Lift Pump Operatic .... .............. ' "~  10

   2 .     Diagram of wel 1 logging system used during                  .:
    ,   ;    character I zat Ion of wel 1 L-8 .... ...................     17

   3 :     Profiles produced by U.S.G.S. well logging
    7       atwellL-8 ................. . ........ .... ......... .     19

   **      Straddle Packer System used to characterize                . ".:.
           well L-8 .......................... . ............... .     21

   5      Surface support system for Straddle Packer  ..........     22

   6      VOC concentrations of Isolated zones during
           packer testing .....................................     25

   7      Distribution of total VOCs In well L-8  ......... . ____     26

   8      Well  L-8 water level drawdown during purplng  test  ...     29

   9      Well  L-8 VOC concentrations during punplng test  .....     30

  10      Schematic of air delivery control system  .......... . .     33

  11      Diagram of air lift purp and sparger footpieces  .....     36

  12      Matrix of depth settings for air  lift pump and          .
     :      sparger ............. ...... .................... ..... .     37

  13      Example of field data collection  sheet  ............. .     39

  I1*      Drawing of v-notch weir box ................... ......     40

  15      Diagram of footplece testing equipment  ... ..... . .....     ^3

  16      Operating air pressure and cost for air lift  pump
           footplece tests .... ........... .....................     *t6
  17      Air lift punplng efficiency for footplece tests
                                    vl


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er • . ~;- •_ v^ --. , ; J;' "-r^- •>:;:-::; .;;.>?-.-•"-; -'; .' .'.
.Removal of major contaminants during air lift puntp
• footplece tests ....'• •
• Removal of minor contanlnants during air lift pump

Cost for air lift pump and sparger combination
Removal of major contaminants during sparger and
Removal of minor contaminants during sparger and
air lift pump footplece tests 	 	
Air lift pump submergence, pressure and efficiency
at three depths In wel 1 L-8 	 * 	
Theoretical vs. NPWA air lift pump efficiency data..
Cost to compress air for air lift pump tests at
three depths 	 	 	 	 	
VOC removals for air lift pump testing 	
Raw water VOC concentration at well L-8 during
air 1 1 ft pump test Ing 	 	 	 	
Pumping efficiency of the air lift punp while
Water flow rates of air lift punp and sparger
tests 	
Cost to compress air for air lift punrp and sparger
VOC removal for air lift purp at 130 ft while
sparging 	 	 	 	 	 	 	
VOC removal for air lift punp at 200 ft while
VOC removal for air lift pu-np at 280 ft while

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     Nunber


•'--.'-':'--v.35..'.."•';  ..-Drawing of electric punp and • sparger at well L-8  ...


•:.'•.* 36 -:  ,VOC removal  by electric punp  with sparger at three
                                                                    Page


                                                                     85



                                                                     88
; 37 ".','_'  .VOC  removal  variation over time with electric punp
:  •. • •  ; . * '. fino spsrQGr •••••••ป*••••••ซ•••••••*•••••••*•ป•.••*

  "   _• •"  *   """;•"-"-"'    ' '        7 '    "' "-    - ' - .  "'.'•"'•"••'--'-  "*-'
 38    ." Cost of electric submersible purp and sparger  '
 -,  -   .        .,           .-....     ...      ,.        -
;39   "-:.• Drawing of air samp ling, system ........ ...........


-**0      Air sampling location diagram of well  L-8  ........
                                                                         . .
                                                                          y *
                                                                        :'.': ••'.-'
                                                                          96.


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              ••/••'••'•' /_'.'•'•'' •.-•'•.' "-      ••   TABLES  "    '   "  •       .'•..,  -  '

             Nurber                             .  .                    .         Page

                 1    Description of NPWA well L-8	".	.....i.	      2

                 2    Historical VOC data from well L-8	     Ik

                 3    Baseline groundwater quality of the Brunswick
              '       Formation, Pennsylvania 	,	     15

                 k    Potential water bearing fracture zones and straddle
                      pecker positions  for well  L-8 	     20

                 5    Well  L-8 specific  capacity  data suunary	     2k

                 6    Well  L-8 VOC concentrations for Isolated zones	     27

               ,7    General experimental design	     31*

                 8    VOC  removal for air lift pimp footplece  testing	     kS

                 9    VOC  removal for sparger footplece  testing  	     59

                10    VOC  removal by air lift pump without sparging	     67

                11    Glen Cove air lift purp operating  conditions	     70

                12    VOC  removal by air lift pumping at Glen  Cove ........     71

                13    VOC  removal by sparging v/Ith air lift puip at 130 ft.     76

                14    VOC  removal by sparging with air lift pump at 200 ft.     82

                15    VOC  removal by sparging with air lift purp at 280 ft.     82

                16    VOC  removal by electric pump with  sparger  	     86

                17    Secondary water quality effects of In-well aeration  .     91*

                18    Results of air sampling of  In-well aeration
                      off-gases 	     97
                                                 ix-.


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                                   ABBREVIATIONS
                                                                                             it
                                                                                             t^
                                                                                             t s
     1,1-DCE    -   1,1-dIchloroethylene
     1,1,1-TCA  -   1,1,1-trtchloroethane
     'c-l,2-DCE  -   cls-l,2-dlchloroethylene
     CCIA       -   carbon tetrachlorlde
     cfpm       -   cubic feet per minute
     CHCL3      -   chloroform
     DO         -   dissolved oxygen
     ft         -   foot
     GC         -   gas chromatograph(y)
     GC/MS      -   gas chromatography/mass spectroscopy
     gpd        -   gallons per day
     HP         -   horsepower
     HPC        -   Heterotrophlc Plate Count
     In         -   Inch
     n          -   number of samples tested
     NPWA       -   North Penn V/ater Authority
     PCE        -   tetrachloroethy1ene
     %RSD       -   % relative standard deviation
     psl        -   pounds per square Inch
     PVC        -   polyvlnyl chloride
     SD         -   standard deviation
     SP         -   spontaneous potential
     TCE        -   trlchloroethylene
     ug/L       -   mlcrograms per liter
     U.S.G.S.   -   United States Geological Survey
     VC     •'".-•  vinyl chloride
     VOA        -   volatile organic analysis
     VOC        -   volatile organic chemical
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                            .ACKNOWLEDGMENT
     We wish to acknowledge the following people who have contributed
their efforts  to this project:  Tucker. Moorshead, Earth Data,  Inc., St.
Michaels, MD.,  for his  role  In  developing the  original  Idea  for this
In-well  aeration  study  and  for conducting  and  Interpreting  the well
characterization tests; Dr. I.H. Suffet, Drexel University, Philadelphia,
PA., for  helping with experimental  design and technical  editing;  Terry
Gable,  Clarence Godshall,  and  William  Smith,  NPWA,. for  field  work;
Charles Hertz, Beth Green Hertz,  James Towson,  and Ylfen Tsal, NPWA, for.
analytical work; Ralph Walter and Dale Relchenbach,  NPWA,  for drafting;
Johanna Brown, NPWA, for word processing  and  editing; and the NPWA Board
of Directors for their support of our research endeavors.

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                                 SECTION 1

                               INTRODUCTION
OVERVIEW          .       '  :,          ,      :  :;'       ,:.       .  :   ;:

 "•'•.  Contamination of groundwater with volatile organic compounds (VOCs)
has  become cannon  throughout the  United States.  (1,2,3)  Southeastern
Pennsylvania and  the  North Perm Water Authority  (NPWA) have not escaped
this  problem.   In  1979 a  large amount  of trlchloroethylene  (TCE) was
spilled  in nearby  Col 1egev111 e, PA.   The Authority  sampled all  3^ of
their operating  wells and  found eight to be contaminated  with TCE and
other  VOCs.   These  wells  were  shut down,   resulting  In a  loss  of
approximately one-third of the system's total pumping capacity.
     Since  that  time  NPWA has been actively  pursuing  various methods of
dealing  with  the  VOC  problem.   Surface  water  was  purchased from  a
neighboring water supplier,  a granular activated  carbon treatment  plant
was  Installed  at one well,  packed  tower  aeration  devices were designed
and  this   study  was  carried  out   to   Investigate    in-well   aeration
techniques.
     This  report  covers  the  design  and operation  of  various In-well
aeration  configurations  examined  by NPWA during  the  time period  of
January  1982 to  May 1985.   The  configurations  Included air-lift punplng
with  and  without  In-well   diffused  aeration  (sparging),   as  wel 1  as
electric submersible pumping with In-well diffused aeration.
     The well  selected  for this study was Lansdale number 8 (well  L-8).
This well  was heavily  contaminated  with VOCs and  was  being  pumped to
waste In an attempt to control the contamination plune.  A description of
the well  Is given  In Table  1.   It Is  In a mixed resldentlal/comnerclal
area, with homes  In close proximity to the well house.
     When  a well  Is found  to be contaminated  It Is  cuuion practice to
pump  It to waste,  In order to  prevent  the  contamination plume frcm
spreading throughout the aquifer.   In-well aeration, by  air-lift punplng,..
can treat the water as  It Is being pumped.  This can reduce  the  amount of
pollutants being discharged  Into the  sewer system (as at well L-8) or, In
some cases, may  treat  the  water to potability.  Treating the water while
pumping  eliminates the need  for construction  of  above-ground   treatment
devices.   In cases where  above-ground treatment  systems are necessary,
In-well aeration may provide a good Interim treatment technique  while the
permanent  system Is being designed and  Installed.   The  in-well aeration
equipment  used  In this  study  was  easily  constructed  from   materials
already  In NPKA stock.
     Shortly after the discovery  of  VOC pollution at  NPWA in 1979,  a
series of  preliminary tests were performed using  an air lift pump or an
electric submersible pump with  a sparger.  No attempt was made  to record

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••^•^•...'r?.--?":-^-•-'"••.V.'.•<-.'  -' -: -V-;,"%'-  "'-r.?-v."V'-..•':'•••!':• ;2!'A? v:'.-v "X  /^/';v:,';/;•-1-•'.•••t;'/.^:;;"lv^r".-";C;A.;;
•:•-.' '.v:-'-- '-•" • ''-'•''•  " '' '•   '    '  '•''   -'• ' '  :- '     • '  '• ••'•'•-"  •'••' ' '••<- '-  -•-•-.••,••', '  ' '•> ---.-v^1* /.^-.'c^-.. :••
:-.v;.  air:to .water  ratios, or  operating  conditions;  however,  even under  these  ./.i .   .Vf.r
 •f.'vj  uncontrolled  conditions,  good  removal  efficiencies were  seen for  TCE  /V ;..~'^i"''
 •;.':..:.'. .-Cabove 80%). \ This provided  the Incentive  for further study of. In-well,.  '   . '  ^
:,.-,-'-'  aeration.-    • '   ''.•••:. •••'•    :. ••:-' ' •.-•'•-.•.-'••.-'•-  -.  •",;•-. '  •.-: .•-'.'•  . •-V.r-''-'iJ":.-1%i :-"-' ':•
                       '•• TABLE  1.   DESCRIPTION OF NPWA WELL L-8
        \..  Location:  West Third Street,  Lansdale, PA.

         •  Depth of Well:  292 feet  (original), 286 feet (present)

           Depth of Casing:  20 feet (8 Inch diameter)             .

       •'_-;  Date Drilled:  1923                  /...-'   :      ;      :;

           Pumping Capacity:  50-70  gpm    .                  ,
           VOC PRESENT
HENRY'S LAW CONSTANT Catm - m
           vinyl  chloride
           1,l-dlchloroethylene
           cIs-l/2-d!chloroethylene
           1,1,I-trlchloroethane
           carbon tetrachlorlde
           trlchloroethylene
           pe rchIoroethy1ene
        8.8
        0.40
        0.070
        0.31
        1.0
        0.30
        0.83
           The air lift punp used  for this study was similar  in design to pimps
     used  by  the Lansdale  Municipal  Authority  (predecessor  to  NPWA)  In the
     1920's.   Compressed air was  Introduced Into an open-ended eductor pipe In
     the  well.   The  aerated water  In  the eductor was  less  dense than the
     surrounding water In the well  and was therefore forced  up the eductor and
     out of the well, because  of  this density  gradient.  The  three test modes
     .of  In-well aeration for this study  Involved purrping by an air lift purp,
     air  lift  punplng in combination with  sparging and  electric  submersible
     pumping  with  a  ?->arger.   The sparger was simply an  open-er
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-  electric punp tnd then treating  It  by aeration.              •   :'     .  ,
\\"i'.;. .:''•  Certain sซicondary effects of  In-well  aeration treatment  techniques
.were also erainlned.   Off-gases In the well  house were  tested  to determine
 •whether hazardous  conditions were  present.  The  air outside the well
.house,   In  the  adjacent  residential  area,  was also tested  for VOCs.
  Bacteriological  changes as well  as corrosion related  factors (changes  In
  pH  or dissolved  oxygen with aeration) were  examined.
     -.The first stage of In-well  aeration system design In this study was
  characterization of  .well  L-8.  This was  done by the  U.S.  Geological
  Survey  (U.S.G.S.) with a  series  of well  loggings.   These tests Included
  callper, conductivity,  temperature,  radiological  and brine  trace logs
  among others.   The U.S.G.-S.  study  determined  possible water zones of
'-  'entry.   ••'='-•-...•'...   '•';;-•    •   .;'•'.    • -  •• ,        ,'•--.•'•
     ..Straddle packers were placed In the well to Isolate the water zones
  of  entry determined  by the U.S.G.S.  Each  of  these zones were analyzed
  for VOCs and  specific capacity.   This knowledge of where pollution was
  entering the well was used to determine the depth  to  locate the aeration
  equipment. .(For  example,  If all the pollution was entering the  well above
  50  feet,  locating the  equipment at  a  depth of  200 ft,  attempting to
  maximize counter-current operation, may not  be cost effective  given the
  cost of compressing air under that  head).
       Three different depths for  In-well aeration equipment were evaluated
  at  well  L-8, based on the findings  of the straddle  packer testing and air
  lift purp theory.  The air lift punp and sparger were  operated  at each of
  these three  depths.  This provided several  types of water and  air bubble
  movement  In the  well,  Including   both  counter-current  and  co-current
  stripping.
       An electric  submersible pump  was  fixed at one  depth  In the wel 1
  while the sparger was tested at each of the three depths used  In air lift
  punp tests.   The decision of where  to place the  equipment during electric
  pump testing was based on the results of the air lift  pump testing.
       Parameters  measured  in the field  during  In-well  aeration  testing
  Included air pressure,  air temperature,  air flow  rate,  water  flow rate
  and water level   In the well.  These parameters allowed calculations of
  pumping  efficiencies  and  air-to-water  ratios.   The  In-well  aeration
  systems tested were  evaluated based  on these  findings, as  well as VOC
  removal  and  cost.

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 v''-,^:'':\".'•'/.'.~;V-. • ''"-"'•'•'!v  ••.•':,""•       :     SECTION 2       • ': .   ''.-.•'.:'  -';   '  -.'•••^o'.-;

 r';- •'"".-•/'•-•';/"-.'••'••  '-*-•'•-.<:'-.''>  '-' -  :'• •-. ••    -"..-CONCLUSIONS-  -   ".  "'.  >;.-'"   --. V." '. '-",-• --"-,: ';v::


 r.-'" "  _,.   - >   GENERAL    .  .  '  .  •'".   ''.':,"'    ,/• • -  -  ••':•,"' -" "'.'•'.:.• ' •/, ..''•"'.'-'  '^-^^"."'^'v

',,-•';•'•'              ..In-well  aeration can be a useful  treatment technique for VOC  removal
       :. on. a  short-term emergency basis.   Purging with  an electric submersible
 ;  :   .  ,' /   pump  while  using  a  spargar  was  particularly  well  suited  to  this
 :.         "     application.    Many  drinking  water wells are  already  equipped  with  a
            .submersible pimp and  the  addition of the air sparger was completed for
               this  study In  a natter  of a few hours  with  readily available materials.
 '•''.    .          For an operating cost of 12$ to 15$ per thousand gallons, VOC removals of
• v  ''•           70% to 95% were achieved  (depending on  the volatility of the compound).
               This  method  of  aeration  could  be   used   to  keep  an   Indispensable
   .            contaminated well  In  service while  a permanent  treatment  system  was
 ,          -  '. desIgned and Instal1ed.                .                        .   •
                     In-well  aeration by  air  lift  punplng (with or without  a sparger)
               gave  somewhat  better VOC  removal  than the electric submersible pump and
               sparger for a  correspondingly higher cost.   It was more  complicated to
               Install and was,  therefore, not  as  well  suited for emergency  use (any
               existing pimp would have to be removed).   Its operating cost and  limited
 '              VOC removal  capabilities do not make It an acceptable long-term  treatment
               technique.

 :              WELL CHARACTERIZATION                            . -                         .

     !,              The U.S.G.S. well  logging Identified two major and 5 minor  potential
               water zones of entry Into  the well.   This  data  was  used  to  determine
 ;              where to place straddle packers for  Isolated zone testing.   The packer
 "             testing accounted for 80% of the well's specific capacity, therefore, the
 :    "         remaining 20%  of the  specific  capacity  was contributed  by  zones  not
               Isolated by packer testing.  Differences  In VOC  concentrations were seen
 ;              for the  Isolated writer  entry zones.  The two most  heavily contaminated
               zones were also the largest  water producing  zones.   The  open borehole
               purplng test  showed  that VOC  concentration  changed  considerably  with
     ;          time.    Over  short-term  tests,   such  as  the  In-well   aeration  tests
     ,i,         performed here, large concentration variations could be expected.

 :         .    FOOTPIECE TESTING                            -                            -

 ;                   The air  lift  pump and  sparger footpleces  were tested  using large
 !  •  '.          bubble  and  small  bubble  configurations.  The  small  bubble   footplece
/    ;          caused greater operating pressures  for  the air  lift punp.   The pressure

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               difference was greatest at high  air-to-water ratios (5:1 to  12:1).  Tlw" : "  " /  :;i;
               most efficient operation of  an air lift pump was  found to be at a much         : f^
               Tower air-to-water ratio (1.5:1)  where the pressure differences  between      .   :;
               the footpleces were very small.   If the air  lift  punp were operated  at         '  ^
               Itsymaxlmum  pumping  efficiency,  there  would be  little  difference  In       '    •
               operating pressure between the two footpleces tested.  If, however, the
               pump were  operated  at a higher air-to-water  ratio In order to obtain     •'•••'-:-_,
               better VOC  removal,   the  small  bubble footplece  would have  a  greater     -    '
             /operating pressure and a greater  operating  cost.             .-  .    .      //~V r--.  -.-  x  :.'
                  .The  two  air  lift pump  footpleces   tested  showed  no  significant
               difference In  air  lift pump efficiency.  The maximum efficiency was found
             .-to be 30-35%,  which confirmed the literature.  There was no  difference  In         '•''''•
               VOC removal brought about by  changing from  a  large  bubble to small bubble
               air lift pump footplece.  Since  there was no difference  In VOC  removal          .
               between  the two  air  lift pump footpleces, and  since  the  small  bubble           -
               footplece would  be  potentially  more  expensive  to  operate,   the small
               bubble configuration was abandoned, and  the large bubble  air lift pump
               footplece was  used for the rest of the  In-well aeration  testing.          .  .       >.
                    Sparging  air  Into the well decreased  the  pumping efficiency of the       '
               air lift  pump.  The small bubble sparger footplece had a higher operating
               pressure,  and  therefore,  a higher operating cost  than  the  large bubble
               sparger  footplece.  There  was  no difference In VOC  removal between the
               large and small  bubble sparger footpleces.  As  with the  air  lift puip,               ซ
               the small  bubble  sparger footplece was not used  for any further testing              I
               because of higher  operating"pressure with no improvement of VOC removals.               *j
                    In the footplece  testing,  VOC removals were similar for similar air-           ;   yS
               to-water  ratios,  regardless  of whether air was  Introduced by  air  lift            .3
               pump  or by the air lift pump  and sparger combination.  Vinyl chloride was
               the exception  to this  as  It  was better removed by  the  air lift pump and
               sparger combination  than by  the air lift ptnp alone.   VOCs were removed
               In  an order which would be expected, based on Henry's Law Constant.

               AIR LIFT PUMP TESTING WITH AND WITHOUT A SPARGER                                   '

                   The air lift pump operated most efficiently at 65% submergence.   The
             .  efficiency decreased as submergence increased, confirming the predictions
               of  the literature.  VOC removal was poorer at the  280  ft  setting  of the
               air lift  punp  than It  was  at 130 ft or 200 ft.   VOC removal percentages'
               for the  air lift   pump alone  ranged from 90.^%  for vinyl chloride  (VC)
               (best  removed  according to   Henry's Law)   to  ^7.4% for c-l,2-dichloro-
              ethylene (c-l,2-DCE) (poorest removal).  TCE was  85%  removed "by air  lift
               pumping without sparging.
                   A particular  air  flow  rate  setting produced  different water  flow
               rates (and  difference  air-to-water ratios)  on different days.   This was
              mainly due to water level changes  In the well which caused  air lift  pump             .  fa
              submergence to change  which,   In  turn,  changed pumping  efficiency.   Raw               II
              water concentrations  of VOCs varied widely  from one test to  the next, as               M
              well as varying within a particular test.  This confirmed the findings of               ฃj
              the pumping test conducted during  well  characterization.                              :  3
                .   As shown  in the footplece testing, the sparger caused  the  air  lift            :  if
              punp efficiency to decrease.   Even though  the sparger caused the air  lift          "   'f*
              pump efficiency to decrease,  the punp efficiency with a sparger was                     ""'•
,  r

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           &^^^
 ^/;•-,-•  higher, .than If all  of the air had been delivered to the  air lift; pump
 |.'-y,::L/;/- /\;;  alone;  therefore,  In'terms'of purp efficiency Cand cost) It was better to
 'a.i '•'_• -'-.-    :,  '-operate an air lift pump and sparger combination,  than the air 13ft pump
 j    •;-  .       alone.   No-VOC  removal differences could be  seen when the  sparger was
 I1       ..•  ;   operated at different depths with  the air  lift  pump.  This  was mainly
 ;-_  , •"-'.'••_••-. ' !-  because of poor  reproduclbll Ity of the sparger tests over long periods of
 ..;-'•••••.    * :  .time.,  All measurement systems were checked  and the most likely cause of
 * ',;       , ,'./•_ variation was  determined to be changing well conditions with time.
 i  :,      ;:     ' .  .The  air  lift  pump  and  sparger  combination  yielded VOC  removal
 i--"•'•" -•'      ""percentages ranging from  98.6% for VC to 65.0% for c-l,2-DCE,  with TCE
 ;-.'.  '.,:,'.   -; :   having  .78.3% .removal.  A higher air-to-water ratio was obtained by using
 j    ,      '•"';  the  air lift purp and sparger combination, which accounted for the higher
 f •;  ' •  -   'VOC  removal capabilities.   The highest air-to-water ratios obtained were
 ;-.."'•  ;       10.6:1  for the air. lift pump and 17:1 for the  air lift pump and sparger
•V !.:'•--'.'.."'  :   combination.   Air-to-water ratio was  limited when sparging to the point
 ,      ";'.      at which water actually bubbled out of the well  head because the entire
 ;-'. ':..   :   ,.  well had  been turned  Into  an air  lift pump.   In  a well  with  a wider
 ' '            borehole the air-to-water ratio  might be higher because water would not
 i    .          be forced  out of the well  as readily.   Also, at well  L-& some  of the
 ;    .          borehole diameter was taken  up by  test  equipment which would  not be In
";'•'-          -   the  wel 1 during  regular operational conditions.                -  .  :
                    Costs of air lift purplng and sparging make this  method expensive
 ;              for  long-term use; however,  It may be useful  as  an emergency short-term:
               treatment  system.   The  electric  pump  and  sparger  experiments  were
ซ.'•             designed with  this In mind.                                           -•„

 ;              ELECTRIC PUMP  AND SPARGER TEST I NiG                .               -      ;'-

 , -  .;.•               An electric-;sa)jrnerstble puip was  operated at  200  ft, with sparger
               testing being conducted at  130 ft,  200 ft  and   280  ft.   The  best VOC
               removal was obtained  with the sparger at  130 ft.   The 280  ft sparger
               depth setting was next best,  with the 200  ft depth  giving  the poorest
 ;              removal.  VOC removal findings  were consistent  with what was expected
 .   '           from well  characterization   experiments.    Sparging  at  130  ft  caused
               counter-current  stripping as water from  the most contaminated  zone was
    •           pulled  past the  sparger on  its way to the pump.  A co-current stripper
               would have been  created by the 280  ft  sparger,  with.at least  some of the
               air. being pulled into  the  purp  before  It  reached  the most  heavily
 :              contaminated zone.  With the sparger directly  adjacent to the pump, most
               or  all  of  the  air  could have been  pulled  Into  the  pump  before any
               stripping occurred In the  well.                                      .
                    Electric  putp  and sparger  testing showed the  same  variation over
 .   .  .. • .      long periods  as  did  the  air  lift purp  and  sparger testing.   With  no
    ""•  --•      other part of the experimental system  changing, this helped confirm that
    ::' ..         well conditions  changing with tir.e  CVOC or water  zones of entry, not VOC
    •'           concentration) could affect in-well aeration.
          .          The VOC  removals obtained  during electric  pump and  sparger tests
               were an average of  82.6%  for TCE,  79.9% for c-l,2-DCE and 92.9% for VC.
               These removals were better than  those achieved by air lift pump ing with
           .    or without a sparger.   The air-to-water ratio used to achieve this better
               removal was 8.2:1, which  Is  lower by half than the maximum air-to-water
  -.'.'•           ratio used In air  lift  pump and  sparger combination  tests.   For the


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\electrlc- pump/and  sparger  combination,' :a  lower
-^achieved better removal than the air lift pump with or without a sparger.
 ,  .   Electric  pumping with  a  sparger  Is  a  good  emergency  treatment
 technique If  the  limited VOC removal  capabilities will meet  your water
 quality goals.  It can be Installed very quickly  with readily available
 materials.  It can be  used to keep  a well  In service while the permanent
 treatment system Is being designed and installed.         .   <          :•
     ; While well characterization was useful during this project, both for
 experimental design and data Interpretation, It would not be necessary In
 an emergency.situation.  The sparger  should  not  be set directly adjacent
 to the pump  to avoid having all of  the  air pulled  Into the purp before
 any stripping can occur In the well.       .       .      .          .  .,• .'-.-<.

"SECONDARY EFFECTS OF IN-WELL AERATION    .        ."';"  ";'/   ;   : /  V''i;   -7 ^:

      All.  methods  of   In-well aeration  tested   Increased  the  pH by  an
-average of O.*t pH units.  Dissolved oxygen  (DO)  was  raised to saturation
 .by all of the In-well aeration  methods  tested.  Water entering the weir
 box (air  and water separator) was  bubbly  In appearance  (actually milky
 white when sparging),  but all  of the bubbles  were gone by  the time the
 water left the weir box.                              •               .    .
      Bacteriological  testing of  raw and treated water was  inconclusive, -
 with  large  variations in bacterial counts  masking any trends.   The R2A
 method  provided  consistently  higher recovery  of  organisms  than  the
 heterotrophlc plate count.
      Air sampling showed  that  In-well aeration would  probably  not cause
 air quality  problems of  Industrial hygiene  concern, however,  It  may be
 considered an air pollution source,  and would  require  the appropriate
 permits  for  such  a  source.    This  would  depend  on  the  raw  water
 concentrations of the contaminants.                            .

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                                   SECTION 3 •;•••-

                                RECCf-MENDATIONS

s;:  .It.. Is  recomnended  that, electric  pumping with  a sparger should  be
',  used as  an emergency treatment technique.   The sparger  should not  be
  placed directly  adjacent to  the pump Intake,  as  this will  cause  the
  bubbles to enter the pump Inradlately and  any VOC stripping effect In the
  well  borehole will  be lost.  Air  should be  added  In slowly  Increasing
.amounts until the foaming water Is just  visible below the well  head.
  This will  .produce the greatest  possible air-to-water ratio.  An  air and.
  water separator  Is necessary.        ,'    •  -:  .  .            ;    .  .     •
-    .   Further air  quality testing should  be  performed  to determine  the
  possible  need  for  air  discharge   permits.    The   necessity  to  treat
; off-^gases  from  In-well  aeration  to remove   VOCs could  negate  Its
  advantages as a  quickly  Installed emergency treatment system.
       Possible corrosion  Implications need to  be further considered.   The
  elevated dissolved oxygen concentration. In  the treated water could  be a
  problem over  the long-term but  It  Is not  known whether  any  additional
  treatment would  be necessary on  a short-term basis.

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   SECTION
IN-WELL AERATION
 HISTORY OF AIR LIFT PUMPING

  .The  Idea of  pumping  with the  air  lift method was  first  tested by
 Carl  Emanual  Loscher, a German,  In  1797.   It's first practical use was 50
 years later by Cockford,  an American. (5)  The  application  was to pump
 petroleum from a  series of wells In Pennsylvania.  It was first patented
.In  the U.S.  In 1865.  During the early  1900's  It was widely used In the
 water works Industry.   The Lansdale Water Company,  predecessor of North
 Penn  Water Authority,  used  a steam powered air  compressor  for air lift
 pumping during the 1920's  and 1930's.   After that, the air lift pump was
 replaced  by more  efficient turbine  or  submersible electric pumps.

 THE AIR LIFT  PUT-IP                .             ',           -   .

      The  air  lift pump  functions  by bubbling  air   Into an open-ended
 discharge pipe In the well.   The water In the discharge pipe (called the
 eductor)  then has a reduced  specific  gravity.   The lighter  water In the
 eductor Is forced upward and  out of the well by the heavier surrounding
 water. See Figure 1.
      Early researchers  (5)  showed  that  when   the  air  lift   pump  was
 operating at  Its  maximum efficiency (approximately 35%),  the  air-to-water
 ratio was low (2  or 3  to  1).  It  was possible  to Increase  air-to-water
 ratios to nearly  16 to 1,  however, the pumping efficiency was reduced to
 7%.   It  was  surmised  from  this early work that compromises  of either
 pumping efficiency or organic removal  efficiency  would have to be made In
 order  to successfully use   the  air  lift  pump   as  a  volatile organic
 chemical  treatment device.                                          .
      Another  consideration when using  an  air lift pump was that  It
 required  a high  percent   submergence  (%  of eductor  below purping water
 level) In order to work efficiently.   The punp was simple to  operate with
 very  few moving parts, therefore,  the maintenance cost  may  end up being
 less  than tliat of an electric punp.

'IN-WELL DIFFUSED  AERATION

      Another  form of in-well  aeration  that was examined  In this  study was
 diffused  aeration, or sparging.  This  method has  proven useful for
 aerating  drinking water and  waste water.  The method  Is  usually employed
 in  treatment  plant situations.  In this study, a  plastic sparge line was
 dropped  Into  the well  and  air was  introduced  through  this line.   The
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)
\ MOM- AERATED
X^ WATER.

Figure 1.  Diagram of air lift pump operation.
                      10
                                                                           f;;i

-------
 t     The sparge line was easily moved to various depths In the well.  it:
 could  be placed, directly  near pollution  entry, zones..  Operating costs
 could be adjusted by changing sparger depth,  as It was "more expensive, to  :
 operate deeper In the well.            ...'-"..  "• >/ ;;   ^      -.'..-./ >   V.^  / :\
      The sparger could be set at a variety of depths'with relation to the
 pump.;* The actual bubble path would  be  extremely difficult to determine.
 Bubbles.could go up to the well head or be pulled directly Into the pump," f
 depending on the relative positions of the pump and sparger.              •-
                 -••'••.'••'.-"                                       f
 WATER QUALITY EFFECTS OF UNWELL AERATION

      ,The primary water quality effect  to  be examined  In  this study was
 volatile  organic contaminant  removal.   Aeration  In  other  forms  Is  a
 proven treatment technique for these types of contaminants.
      Studies using air  lift  pumps as sampling devices  have  shown  that a
 number  of secondary  water  quality effects were  also  likely with  an
 .In-well aeration system (6,7,8).  Air lift pumps used In monitoring walls
 could  raise  the pH as much  as 1.0  pH  unit  as compared  to  a perlstallc
 pump or a bailer (8).  This was because of bubbles of  air In the eductor
 stripping dissolved C0_.   Tne  same study  also  showed  effects on various
 metal  concentrations.   Iron concentrations  were  reduced  by 32%  when
 pumped by the air  lift  pump  as opposed  to the perlstalIc pump.  The zinc
 concentration  was  reduced  by;: 17%..   Calcium,  potassium,  magnesium,
 manganese end sodium  concentrations  were not affected  (8).  Formation of
 Iron .oxides  was  probably  the  reason for. the   loss  of   Iron.    Zinc
 adsorption onto the  Iron  precipitates  was cited  as the  reason for the
' drop In zinc concentration.
      Dissolved  oxygen Increase during  In-well  aeration was  of  concern
 because of possible corrosion  Implications.   The air was Introduced Into
 the water at depth, and  therefore was under  pressure.   This pressure may
 have  caused more  oxyqen  to  be   dissolved   Into  the   water  than would
 normally occur with conventional above-ground aeration systems (9).
ft

                                    11
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                                            SECTION 5

                                      WELL CHARACTERIZATION
           .'PURPOSE OF CHARACTERIZING THE- WELL

               -  Well characterization  Is  helpful  when designing a  treatment system
            for a  contaminated well.  Knowing where and how contaminants  enter the
           ;well can be used In a variety of ways.  In seme cases a section of a well
            may be sealed  off  to prevent pol 1 utant  entry while  still  permitting the
            use of the  well without  treatment.   Knowledge of pollutant  entry zones
           ; can help to Interpret sampling  results,  especially  when a  small sample
            pump  Is used which  may not  be collecting water  representative  of the
            entire  well.   This could  lead  to  over- or  under-estlmatlon  of  the
            contaminant  levels.   Well  characterization can determine the geologic
            materials adjacent to  the  wall.  A knowledge of  contaminant zones  of
            entry, together with an understanding of the geology near the  well, can
            aid In contaminant source location (10).               .
           ,      In  the case  of in-well  aeration, effectiveness  of the  treatment
            method  could  depend on the   placement of  equipment  In  relation  to
            contaminant  zones  of entry (11,12).   Knowing  the water  and contaminant
            entry zones enabled the design of test configurations which would examine
            both counter-current and co-current stripping.   The well  characterization
            enabled the  Interpretation of test results In relation to the equipment's
            proximity to contaminant entry zones.
                 The  well  characterization  performed at  well   L-8  was designed  to-
            answer specific questions relating to  the design of  the  In-well- aeration
            equipment and the  Interpretation of  test results.  This  was accomplished
            through the following:                        .  -             . v .
                 1.  Determined as-bullt configuration of the well       "''".":'
                     (I.e., total depth, dlameter(s), casing length)
                 2.  Determined location of water zones of entry.
                 3.  Determined location of VOC zones of entry.
                 k.  Determined specific capacity of entire well and
                     Individual water zones of entry.                              •
             ,    5.  Determined static water level.                .          / -.  •.
                 6.  Determined how the quality of the water entering
                     the well varied with time.      •
            " ,   7.  Determined the depths at whicli to place the In-well
                     aeration equipment.                   .

                 The characterization of well L-3 was done In four parts.  Historical
            data was compiled and-reviewed.  A series of well loggings were performed


             ::  •-• -   •"'. '   -;     .                12                 -  ••- v  .••-;-; - T:  y/

-------
 i •
 I.
-; 'to.determine possible water zones of entry.  Straddle packers were used   .
'••'-'. to Isolate, pump and sample the water zones of entry.  A pumping test was
 }  performed  to gather further  hydrolog leal  data.   Each  of these  will  be  .
  • discussed  In detail In the following pages.                   ' ,;   .   .-  , ;r
   REVIEW OF HISTORICAL DATA                                      -    ..    v .

     .Records of: the North Perm Water Authority were reviewed to compile
   as much  Information concerning well  L-S  as possible.  Since the well had
   been  Inventoried by  the Pennsylvania Geological  Survey  during earlier
   studies  in  the area,  reports published by  the Survey were also reviewed
   C13/11*).  The  driller who constructed the well  was  contacted and prior
   pumpage and water quality data were  reviewed (15).                   .
      .  Unfortunately, when the well was drilled  In 1923 the contractor did
   not  record .changes  In  the  llthology  of the  rock  penetrated or  any
   Increases  In the yield of the well  that occurred  at various depths.  It
   was  assumed  that,   like most  other  wells  In  the  NPWA system,  well
   L-8 penetrated layered consolidated  rocks  of the Brunswick formation and
   water entered  the open borehole  below the  casing at various depths.  The
   actual quantities of water and  related qualities were not known and that
   was the focus  of the well characterization.
        Well L-8  was  In  continuous  operation from 1923  until  It was taken
   out of service In 1979 because of VOC contamination.  The well was pumped
   continuously to waste  (to contain the VOC contamination plume) until this
   field work  began In February 1983.   Table  2 shows VOC concentrations in
   well L-8 during  the time It  was being  pumped to waste.  The 1979 samples
   were analyzed  by gas  chromatography  (GC) at a local contract  laboratory.
   The  March  1981   sample  was analyzed  by  the  U.S.  EPA at  Annapolis,
   Maryland,   using  gas  chrarstography/mass  spectroscopy  (GC/MS).   The
   December  1981  sample was analyzed by  the  U.S. EPA at Cincinnati, Ohio,
   using GC.
        As Table  2  shows, well  L-8 was heavily contaminated with a variety
   of halogenated volatile  organic  chemicals.   TCE  was found In the highest
   concentrations,   with   c-l,2-DCE   and  PCE  also  present   as   major
   contaminants.   Also  found  at  lower  concentrations  were VC  (a  human
   carcinogen) and carbon tetrachlorlde (CCm) (an animal carcinogen).  Also
   present   were   chloroform   (CHCL3),    1,1-dichloroethylfcne   (1,1-DCE),
   1,2-dlchloroethane  (1,2-DCA), and  1,1,1-trlchloroetnane (1,1,1-TCA), all
   of which are suspected carcinogens (16).
        Well L-8  Is located In  a  heavily populated,  mixed residential  and
   commercial  area  of  Lansdale,  PA.    Possible  sources  of  the  VOC
   contamination  were  numerous..  The   most  likely source,  however, was  a
   commercial  facility  directly across  the  street  from  the  well.   VOC
   degreaslng  agents were known to have  been used  at the  facility  In the
   past, and In the early 1970's, the building was destroyed by a fire which
   caused  several explosions.   Hundreds  of  thousands of gallons  of water
   were  flushed   over  ruptured  storage drxms,  which  is suspected  to have
   contaminated the groundwater in the area.
        Natural groundwater quality  Is  controlled by  the chemical nature of
   the rocks  In the aquifer and the residence time of water  In the aquifer.
   The  natural quality  of ground  water  in  the  Brunswick formation  is
   represented In Table 3.   The table  condenses  data from  28 wells  In the
                                                                                                    1
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                                               13
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are not felt to be Influenced by
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•:- r?1 ' NPWA records of natural water quality at
'.:'"':--s -V: - ^ ;•.;'., -.., TABLE' 2. HISTORICAL voc
'.''.>..:''. ' • '
'••':•'• ''-•• '-? •- '•'•' •'".•- • - , - • ; '••• •..-.
: • "•;•• PARAMETERS •
'-' CHLOROFORM :
• BROMODICHLC^WeTHANE
DI BROMXHLOROI^THANE
• BROMOFORM

' DICHLOROIODCtCTHANE
. VINYL CHLORIDE
. 1,1-DICHLORQETHYLENE
. .1,1-DICHLOROETHANE
; . CIS-1,2-DICKLOROETHYLENE
i 1,2-DICHLORCETHANE
J 1, 1, 1-TRICKLOROETHANE
I ' CARBON TETRACHLORIDE
1, 2-DICHLORCPROPANE
" . TRICHLOROETHYLENE
1, 1, 2-TRICHi.OROETHANE
1 , 1 , 1 , 2-TETRACHLOROETHANE
TETRACHLORCCTHYLENE
' 1, 1, 2, 2-TETRACHLOROETHANE
' . CHLOROSENZEfrS
1, 2-DIBROMQ-3-CHLOROPROPANE
BENZENE
I TOLUENE
] ETHYLBENZENE
i . BROMOBENZErS
! ISOPROPYLBENZENE
| M-XYLENE
! STYRENE
i 0- + P-XYLENE
I ' N-PROPYLBENZENE
1 ' ' 0-CHLOROTOLUeฃ
; . P-CHLOROTOLUENE
[ . M-DICHLOROKN2ENE
1 0-DICHLOROBENZENE
|. P-DICHLORO^NZENE
{ .
ALL VALUES ARE IN ug/L
NA - NOT ANALYZED
LT - LESS THAN
i tO - NONE DETECTED, LOV^R

1 ' •'• - ••-''••• .
1 - . " .
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. '\ ' ' . ".' "
>.->"~^S^' -': '•'' - " •'•"'• •• ••••;;.•• •,

, DEC 1981
(GC)
---V-8;9 '
LT 0.2
LT 0.5
LT 1.0

LT 1.0
• 35. '
6.7
LT 0.2
400.
0.43
7.0
0.58
LT 0.2
650.
LT 0.5
LT 0.2
230.
LT 0.5
LT 0.5
LT 5.0
LT 0.5
LT 0.5
LT 0.5
LT 0.5
LT 0.5
LT 0.2
LT 0.5
LT 0.2
LT 0.5
LT 0.5
LT 0.5
LT 0.5
' -. LT Q.5/
LT 0.5





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BASELINE GROUNDWATER QUALITY OF THE
-;;^&S

BRUNSWICK
1;-.; -\;- :;--v/; :•;,.: <-M:"V;>' -:--: ^ •:^ ^ :-.-,. :>FORhwr I ON, /PENNSYLVANIA • ; - •• . > -:-;.;;•.•
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CONSTITUENT WELL SAMPLES RANGE

. PH

Specific
Conductance

Nitrate (as NO-")
Chloride
Sulfate
Sodium
Iron
Manganese
Hardness(as CaCO,)
Bicarbonate
Total Dissolved
Solids
.




27


25

27
27
27
22
28
19
29
29

25





5.2 -

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172. -
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1.0 -
6.3 -
3.2 -
0.01 -
0.01 -
32. -
37. -

66. -




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MEDIAN

8.1


959

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31.
370.
22.0
1.6
0.38
500.
298.

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7.2


381*.

6.5
8.5
31.
13.
0.15
0.01
100.
163.
••'..•
263.







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UNITS
Standard
Units

Micro
mho/cm

mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1

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              " Average concentrations of samples collected at v-vell L-8 from 1970
             _ -• to 197.9  ..•'..   •..-.  .-. ..;.;. .   •—.;"•' .--•.•-   ;  '  •  . --..,-'.,'.-     •  -..:.

                   Generally,  ground\vater  quality  In  the  formation  Is  hard to very
              hard, slightly alkaline and moderately mineralized.  Groundwater at well
              L-8  Is  similar  but has  somewhat higher than average  concentrations of
              chlorides, hardness and total  dissolved solids.            •     ,

              GEOPHYSICAL WELL LOGGING         ;     .

                   S*jbsurface   llthologles,   well  bore  features  and  borehole  fluid
              characteristics  can  be determined  using  borehole  geophysical  logging.
              Borehole geophysics can measure the  electrical,  physical,  chemical  and
              acoustical properties of  adjacent  geologic materials and  fluids both In
              the borehole and adjacent formations C10,18,19).                 .
                                                 15
fev.

-------

      Borehole  geophysical  surveys were  undertaken In well  L-B with  the
.following objectives:                ,       .       .-        .•;..-•-;.-.

Vv   1.  To .locate-potential water-bearing fracture zones.              ,••. :.
 "\" . 2.  To locate  relatively  smooth borehole  segments for  the
  X     placement  of  Inflatable  packers In order  to  Isolate the
  ;; >  .  : = water-bearing fractures  zones.
;  .;." 3.  To Identify  1Ithologle changes  (slltstones,  sandstones,  etc.)
 ; ,.; -k.  To determine  well depth, changes In well  diameter  and  casing
  '.'-"- -"length.":  ..   .     •'  -:  ';        .       '      '-.-  • -  .  '-  ..•_•  .-   .•

  f.,  The  geophysical  logs employed  In  thJs  study  Included;  callper,
garnna, spontaneous potential  (SP), resistivity,   fluid   conductivity,
temperature, and brine  tracing.   In each Instance  a sensing  probe  was
 lowered to  the bottom of the well on a  cable, then the probe  was slowly
 retracted   as   data  was  collected  at   the  surface  (see  Figure   2).
Continuous  readings were recorded on an  analog strip  chart  recorder.   The
 logging at  well  L-8 was performed by the U.S.G.S.   Information  concerning
borehole  geophysical   logging  procedures can  be found  In the  literature
 (10,18).
      Borehole  diameter and roughness were measured using callper logging
equipment.   The  hole  diameter was  measured  by four callper   arms which
were held against the  borehole by springs. The  arms  opened and closed as
they moved  up  the borehole,  drawing  a picture of  the physical  dimensions
of  the wel1.
      Resistivity logs  were  employed to  aid  In the  location  of   bed
boundaries  and general changes in 1Ithology,  which were associated with
water-bearing  fracture zones.  Resistivity logs measured the  resistance
of   the  flow  of an electric  current  from one  point on  the probe  to
another.  Generally consolidated  rock had a high resistance because of
 Its low porosity.  V/hen the rock became more porous  and contained a more
conductive  fluid the borehole  log showed a lower resistivity.
      Spontaneous potential  logs recorded the natural  voltage developed In
the  borehole due to dissimilar fluids contained  In the pore spaces of  the
formation  and  In  the  borehole  itself.  SP  logs aided  In delineating
formation   boundaries  and  certain   llthologles   Csuch  as   shale   and
sandstone).   SP  and resistivity  logs were run  simultaneously  using  the
same probe  and the  resultant  log  was called an electric  log.
      The measurement of natural garrma rays emitted from the formation  was
used  In  conjunction  with  electric logging  to differentiate   strata.
Sedimentary rock,  clays and  shales all  had  a unique  gamma  signature.
Places where  different strata  intersect were  possible  water ^producing
;zones.
      Conductivity  logs  measured   the relative  conductivity (Inverse  of
'resistance) of  the  borehole  fluid.   This  logging  technique  did   not
'measure  the  specific  conductance   of   the   fluid   because temperature
compensation was not provided.   Conductivity  logs were  used to  identify
differences In water  quality  due to fracture openings  or breaks in  the
'casing.   Conductivity  logs  could  also  locate   stagnant  water  In   the
borehole  and water that was  moving  from  one  zone to another  because of
'differences In head.
'i     Temperature logs were used  to  measure the  temperature of the water
                                     16

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                      Figure 2.  Diagram of well logging system used during

                               characterization of well L-8.
                                            17
  X •

 t-.--'X

 Li

-------
;Imnedlately  adjacent to  the  sensor. 'Thermal  gradients In 'the borehole
 were  examined-'to locate  potential  fracture zones. ''Temperature logs can
? "also  bemused to Identify water  that has recently entered the  aquifer as
\naturar, or artificial  recharge.  _   .  ..-•• - •-."- /."A '..•-,-•••- '-••--.   -.; -..- : :;-'.:•; -"•/':•  .-.
-:. •:'..'-.-:":'Brine' treeing  was used to measure the direction and velocity of the
 borehole  fluid  at  selected  depths  In the  well.   A slog of a  saline
 solution was released  In the borehole at a particular depth, then.It was
 tracked with the fluid conductivity probe  as  It  moved up and down the
, well.  (20)    •    ..--•'•   -   ;   :'	•   ';,    •••.••;,   "  -,.-.•-  ;-•,•:/  ^
 ,; ;  Well  L-8 was  logged on February  17,  1982  by  the U.S.  Geological
-""'•'Survey's Pennsylvania  District Office.   Reduced profiles of the callper,
 .natural gamna,  resistivity and SP logs are shown  In  Figure 3.   Potential
. water ..producing fracture zones  are marked on  the figure along with the
 positions  of the   straddle   packer system  when  It  was subsequently
 employed.  •'  ''-';."-'..".-"• ^'  :'•-. ..--.• . .•  .• -:-'.''  •  :  '•   ••'•'.'••••. -•:,'.-;  ..'•.-•.;
      The well logqlng  data  was cohplled  and plotted by  hydrogeologlcal
 consultants  to North Penn Water Authority. (21)   The consultant's report
  Indicated that no one single well log was sufficient to characterize the
 well.   Instead,  the log  plots were compared  by depth and when fracture
  Indications  were present on  several of the  logs  at  a given depth,  that
 depth  was chosen as a  possible water zone of entry.
     .The  logs Indicated  that the casing  In wall  L-8 extended from the
 pump motor  base to approximately 20 feet  below the  ground  surface.   The
 callper log  detected major borehole enlargements  associated with  zones 3
 and 6.  Other enlargements wers  encountered  at zones  1,2,4,5,  and 7.
      The major enlargement at zone  3 was associated  with a peak In gamna
 activity  Indicating a  probable  change  from  a sandy  llthology to a low
 permeability slltstone or mudstone.   The  resistivity log  Indicated  a
  relatively  low resistance at  this zone which may  have been  related to an
  Increased volume of water In  a water producing fracture zone.   Zone 6 was
 associated  with a marked decrease  In  natural  garrma  radiation,  possibly
 because of  an Increase in the sand  content of the associated bed.  Zones
 4,  5,  and 7  also appeared to be associated with  relatively lower gamna
 signatures.
      The overall  llthology of the sedimentary rock sequence penetrated by
 L-8  was  fairly uniform with  low  permeability  siltstone  and  mudstone
 apparently  dominant.   Beds  with Increases  In  sand  content appeared to
 occur  between 73 and 92  ft,  151 and 170 ft, 182  and  195 ft, and  254 and
 263 ft.         -          •  .           ' •  -        :   -.-•.•     •"
      The  fluid   conductivity  log  (not  shown   due to   difficulty  In
 transcription from  the original plot)  Indicated a major change In fluid
 characteristics  at  50 to 60  ft  and  ..itnor changes at  172 ft, 188  ft, and
 264 ft.  The temperature log  (also  not  shown) Indicated a major change In
 fluid  temperature at 56 ft,  a minor change  at 186 ft,  and a very subtle
 change at 244 ft.   The brine  tracing logs  showed a major discontinuity at
 approximately 70   ft   arid  again  at  136  ft.   A minor  deflection  was
  Indicated at 180 ft.                .       .
      Based on the  results of the geophysical  logs, seven potential water
 zones  of entry and  Intervals  for straddle  packer testing were  Identified.
 These  Intervals  are shown on  Figure  3 and  in Table 4.
                                      18

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   :w!ฅป&^^^
   Vfiซ^^^^
<ฃ>
 DEPTH  .

.FEET.   PACKER  FRACTURE.. .CALIPER

         BETTING.  ZONE,     --.LOG
                                                                                            SPONTANEOUS::
                                                                                            '-'-^'--'':'•'•••'''•'"
                Figure 3.  Profiles produced by U.S.G.S. well logging of well L-8.  ;(

-------
               VTABLE k.  POTENTIAL WATER BEARING FRACTURE  ZONES AND STRADDLE  PACKER
              ••';;'; -/••.•-•;' •--.    -.. :     .POSITIONS  FOR WELL L-8       ; .     .. •   \-  :•..<
                                      CFEET  BELOW-CASING TOP)                       -

. . . Straddle
Potential
Fracture Zone
Fracture Zone Location
:•'! ••:"'' •'".
".?-• - ,." " :
-'••3 '.'•-
4 ;
5 • - • . '
.6
7.
22
-;' ,-53
72
126
156
188
260
- 32
- 61
- 86
- 130
-161
- 196
- 261
ft
ft
ft
ft
ft
ft
ft
Packer Position
Center of Upper Center of Lower
Packer
28
47
70
121
152
182
252
ft
ft
ft
ft
ft
ft
ft
Packer
47
66
89
140
171
201
271
ft . -
ft -'•-
ft :
ft
ft
ft
ft
               STRADDLE PACKER TESTS

                  . Discrete  zone borehole testing  utilizing  packer equipment has  been
               developed  and used  by petroleum engineers, engineering  geologists  and
              . hydrogeologlsts  for  many  years.  By  far  the greatest  application  of
               packers  for  borehole testing  has been  by  the petroleum  Industry  and
               engineering geologists for  fracture permeability evaluation  at  dam and
               foundation sites.  The use  of packer technology In hydrogeologlc  studies
               at  North  Penn Water Authority  has been reported by  Suffet, et al  (11).
               Shuter and Pemberton (22) described early U.S. Geological Survey  systems
               along  with  a  system which they developed  for  borehole  testing  and
               sampling.  Cherry  (23) describes  a portable  system developed for sampling
               discrete  zones in wells  and Koopman,  et  al (24) describes a system of
               Inflatable packers used  In  multiple-zone testing of water wells.
                   Straddle  packer tests  can  provide a variety of  information In wells
               having multiple screen or water entry points.  Because discrete sections
               of  the  borehole can be  Isolated  when straddle packers are  Inflated,  the
               tests can be used  to determine  the following:

                   1.  Head  difference  and relative elevations of the  isolated
                       zone  and  zones above and below the  packer system.
                   2.  The quality of water punped  from  the  isolated zone.
                   3-  The specific capacity  and drawdown  characteristics  of
                       the  Isolated zones.

                   The equipment used  In  this study was  fabricated  by  Earth Data, Inc.,
               St.  Michaels,  MD.   A  diagram  of  the  In-well portion  of  the   system
               appears In Figure  4  and the surface support  system is shown  In  Figure 5.
                   The  procedure  for  straddle packer  testing  In  well  L-8  was  as
               follows:                            .

                   1.  Measured  lengths of lift pipe  and added sections to reach
                       the desired depths.
                   2.  Lowered sample tubing  and wire into well with lift  pipe.


                     .                             20                    •    '
{•"•• •".'-
i.  - ; •'-'
.•' -   >••
il :*--X

-------
                               v^F^-*3~f*'r&r-rr3&&F?;
                               "'•/f-T.'V.-* '.'^^'X-w
r^^^ro^^^v^TsWf^.
^>sagtfa^'j&ffH^'"a''g^^
                      OPENING FOR
                      WATER LEVEL
                      MEASUREMENT


                      PU,kAP 5RACK.ET-
                                            TO^RFACE
                                              fn^      LIFT Pipe
                      V2BTU6E FOR WATER
                      LEVEL
                       BELOW LOWฃR
                         PACKER
                                                       UPPER PACKER
                                                       AOJUSTA6LE
                                                       D16CHARGE PIPE
       '/a." TUBE TO IW PLATE
                                                       LOWER PACKER
                      Figure 4.  Straddle Packer System used during characterization
                                of well L-8 to pump isolated zones.
                                              21
I

-------
SOURCE
                                     PUM9

                                   CONTROL BOX
                                                           CABLE REEL
         Figure 5." Surface support system for,straddle packer apparatus.
                                                                     '/z. IN. TUBI
                                                                     FOR WAT
                                                                     LEVEL READIN65'

                                                                                   &S&J-
                                                                                   ?•*ฃ&&?

-------
         'Cut 1/2 In tubing;  measured water levels In the lower,  middle         :  .  •
_•/,•"    and upper zones with packer deflated.            .     .   '.     :  :',...".
  .    *f.   .Determined hydrostatic: pressure because of submergence  of each     \.  - .  .^
    . -." ."i. packer.  •  '• .  "      •_          -  --  -    •    •       ../-   -  :.'•   ;':';. '. •? v->'
     • 5.   Determined the necessary packer Inflation pressure by adding         v "  •
 :. •'.;'•';'• .18 psl  to the calculated hydrostatic pressure.                          '   '
     •'.,6.   Started punp with packers deflated trying to maintain a   .
   '       constant rate of discharge.                            "   .      . " .  _:     ;   5
  . -  . 7.   Measured water levels and pimping rate.  Collected samples      - •    ;  , ' i','"-^
          for volatile organic analysis CVOA) just prior to the end       "   .           j
     :    of the  step.                                          -             .:   "";     j
   '.•'. 8.   Inflated upper packer Cthe resulting Interval was referred      .!       -•'--,-    ]
    ,    .  to as the lower composite test).                       .   ...  ^      ;;  ;       -1
     : 9.   Measured water level  changes and pumping rate.          '      '     V"  .  :   -y
     10.   Collected VGA sample just prior to the end of the step.             "       ;.  j
     11.   Deflated upper packer and Inflated lower packer Creferred                .,    .1
          to as upper composite test).                           .       .        .      "]
     12.   Measured water levels and pumping rate.  Collected VGA   *          .       .-t'"\
          samples just prior to the end of the step.                                     j
     13.   Inflated upper packer and left the lower packer Inflated                   .- :]
          Creferred to as the Isolated test).                                        .   •-'
     14.   Measured water levels and purplng rate.  Collected water              -   ...   j
          samples for VGA.                                                  :           ;
     15.   Stopped punplng, deflated packers, spliced 1/2 In tubing and                  ;
   .       moved the packers to the next position.                     .          "   .• •  \

      Zones 1 'and  7  dewatered  rapidly during the  testing,  therefore  only              r
 limited  measurements were made and no samples were collected at  these two              •
 depths.   Drawdown  In  the  other  zones  ranged frcm  1.49  to  38.34  ft,              :
 Indicating a  wide range of response to  purplng.  The  head  differences             '•']
 between  particular zones under non-ptuplng conditions ranged between 0.12              .;
 and  38.24 ft.  This Indicated the general  effectiveness of the  hydraulic              {
 seal  created by  the packers and the small  potential  for movemer.t between              j
 portions of the  borehole.                                                              j
      The specific  capacity  of  the  composite  segments  and the Isolated              :
 fracture  zones  were  calculated  and  compared  with  an  open   borehole              :
 specific capacity Csee  Table  5).   The specific capacity data shows  that
 zone 3 contributed the majority of the well's yield at  37%.   Zones 4,  2,              j
 6,  and  5 contributed  22%,  15%,  6%,  and  3%  to  the  yield of  well  L-8,              j
 respectively.                                                                       ••  ]
      The average open hole specific capacity was 4.75 gpm/ft.  The sun of              >
 the   specific capacities of  each   Isolated  zone  totals  3.82  gpm/ft.              J
 Therefore approximately  19% of  the  total  specific  capacity of the  well              j
 was  contributed  by portions of the  borehole not Isolated during straddle              j
 packer testing.
      Figure 6 and Table 6 show results for  each VOC  Individually.  A bar              ,
 graph showing the sun of the various VOC concentrations for each Interval              •
 tested appears in Figure 7.  Vinyl chloride data  was  not obtained during              -j.
 packer   testing.    The   figures  graphically   demonstrate  the  general           .   .;
 distribution of  contamination In the well borehole.                                   . '
                                    23


-------
^
 y"
 f •. •
: . -
TABLE 5. WELL L-8 SPECIFIC

SPECIFIC CAPACITY (cjpm/ft of
PACKER UPPER
ZONE LOCATIONS • COMPOSITE
1 28-47 0
2 47-66 0.91
3 70-89 2.31
4 121 - 140 3.24 .
5 152 - 171 3.63 .
6 182 - 201, 4.62
7 252 - 271 -

	 .• ' '.'''." '•''. -: •'• ' '•'••;•'•• .' •^•'••.' V-:.'.- • ..'•'••''• ^-TV'.^ L
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• ." • ' .'.••."• •.'!.•> •• >"• . ' • '- • „'..-• -•.'•;•::,.-'•- •:•' •.,ซ.•'
.. . . •''''.•''•, '.' .- •' '.'.". •-.•'... .':t. ...•._.•=. .• ••,;,•';;'., ''."•"'.";'•'''{•:
• . .'' • ' •.'.. '•. : "•.;.' "';'.'.-'•'-.' *"• v '.;.'•".•'.'•... '"-'• '•..": '•".'>'.' 'v>' ''y;'r;r*j4'-
.•'••,'.• '• • ': '•••'.•' •• '' :' '•'>'<'• V :.' !"•'••...'•'• ''V '•'.' '-^ --';',''' '''•V.i''v;.:'<'''-,:v'J'
CAPACITY DATA SUMMARY • •.••'''••'•/' ; '" • -^ ':•••"•: ' ' .' "-'' "'^^^^•J^

drawdown) ' :: % OF OPEN HOLE SPECIFIC CAPACITY P'..?^- 'v'v^':
LOWER ' OPEN '.•-.'• •' .•-•."• •"•':'-.-^-:^--:^':>.
COMPOSITE ISOLATED HOLE "UPPER LOWER -ISOLATED... .1 •:•• ;;.' '.tv t^. ^^"'
- ' '"••- ฐ ' ":' -"."•' - : -•-'.-•'•-• •-••:/:-:^V:-'';:W|^
4.78. • 0.79 5.16 . 17.6 ' 92.6 ',"•;• -.15.3 ' :. . :/'\' •%.>-^'v;V:^;
2.73 1.58 4.29 '54.0 64.0 ," 37.0 ?.'v /:v^;!;V^
; '. '-:-.': • •. •• -•....:.>.;•:, ; -.• ,:^--^::^^,
' 2.86 . ' . 1.03 , . 4.62 70.0 '•;• 62.0''' '/22.0 -.'/• , .**.. '^^-^^ 1-
.' 1.03 '.-'•. 0.15 ''I ,^.^ •.••['• 7k.O' ^':---- 2\.0 .^^ ^.O' .^.''^^f^^^fr^-
0.22 -'. :. ' 0.2?" - •'.'ป.75-ti; 97.0 "j: ,'/'5.0; ' yf:' '.6.b/"V^.-^^^^i^
. . -. . . 	 	 ' ' v • .v; ...'v"."--.".- -,.'.•:
• . • . • • . • ' - •••-.,-!,.•; ...V."'-. ' • •.••_••;
}' Average of previous four values . . : . V - . '."'-•/; -.?v ^ '•>.;;./
i , "' ' ••• - -v>' • < •'• '- "V". "•"•"."'' •"" i' '*•
. : ,_,.„.,,•( • ,J .^ ; (- '•' ;.^ , * y ,'ซ• / '..-_,••
. • • • ' ' . •''.'•< • . '. • * ''••>'•••'•,..< •'.•/ •'•'-ซ•'• -" ' ' . ' '•" >'v, -" 'J*1 *y *,.;,••'; • f * .
• • v " ,• • • • -..-.-..• • •, ... • ,*v •• '11 . .i-r / .•-.'•'• r .,• \-
•-.-.- • ' . - ••' • •' ;• -- -.•.-,-. •••:'<.••:••• ••.:--•./—••:•;;"•• • ••.-.•/•• V-;1.; :-i,^:^.jt-v
'•••'.. • "-.•••>'. '. ' ' ' •' '. :'•'•:••-': '•'.,"" '-.""."•""-.'-i' .'•','" '•••-.'. "•./\N-;;V; L^:':^s.-';r:;v<^^'/^
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- .' , . . "'•.. .'.'. -• ' ^ •.*•'.. \. ' .'. '',•''" .V ,.;•'•:••. ••• ,VK'.\,ji I/ V- v'" '••' ' ' " •.T'--'','.>'';i-^)^;'-f'i;^;'ii
; : ..••. : • •' V ••"•• '•'•••',•,';.'••'," ' •. ; '.•• " •- v '••'.-.:'"''' •'"'"::''=.- !'i:S?''''V:fy'',.:V'^^.'-',. ^.^'^jf^&K$:'$

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                - 700 -

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              S ••-'•-
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                                                  1.1 -DCE
                                  1.1.1-TCA
                      0    20    4O    60    BO    100   120   14O   16O   18O   2OO
                                      DEPTH OF ISOLATED ZONE (TCEO

                      Figure. 6.   VOC concentrations for isolated -zones during
                        .     "    packer testing of well L-8.                     •"'•'.
                                              25
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      Upper Composite
  T
  4
ZONEf
 Composite
                                              -I	1        T
                                              5       6        7
                                                   Isolated Zone
                                                                                 ,:f
                                                                                  rl
                                                                                 -I
          Figure  7.  Distribution of total VOCs in \tell L-8 as
                    determined by straddle packer testing.
                                 26


-------
        TABLE 6.  WELL L-8 VOC CONCENTRATIONS FOR ISOLATED ZONE

ZONE ft . •
DEPTH (ft)
1, 1-DCA
c-l>2-DCE
1,1,1-TCA ...
ccL4
TCE
PCE
TOTAL VOC
% OF WELLS
YIELD

•'• 2 ' '
47-66
2.1
105
8.1
0.5
363
,58
536

15%
CONCENTRATION,
' :' -3' '" • : 4 • -
70-87 121-140
6.1
289
10.5
0.5
710
234
1250

37%
21.3
. 212
.16.7
3.3
483
118
857
. ••
22%
ug/L
• . 5 . •' ;
152-171
20.6
^ • 182
16
3.0
398
102
724

3% "
f, '-A' ."'•': "
182-201
6.2
256* .
4.0 .
0.5
466 :
• 33 .. ; ." ' ..
,' 765 ':

, 6%' V. '•' •••.-.:•
     The  Isolated sample  of  zone  2 snowed  that  this was  the  least
contaminated of  the  zones Identified  In  the well logging,  (see  Figure
7).  The upper composite  sample was less contaminated than the  Isolated
sample,  Indicating  that cleaner water must be  entering the well  above
zone 2.  Since  zone  1 did not  produce any  water, there must be a water
production  zone  between  zones  1  and 2  which was  missed by  the  well
logging.   The lower  composite  sample was  considerably  higher  In  VOCs
than the  Isolated zone sample,  showing that  the water below zone  2 was
more heavily contaminated than that at or above zone 2.
     Zone 3 results showed a dramatic contrast with zone 2.  The  Isolated
sample at  this zone  showed It to be the most  heavily contaminated water
producing zone  In the well.   This  zone  also produced the most water of
the zones  tested, at over one-third  of  the well's total capacity.   The
major contaminants (TCE, c-l,2-DCE and PCE)  were all  found In the highest
concentration  In zone  3.   It  was Interesting  to note  that  the  minor
contaminants  did not  reach  their  highest  concentration until  zone  4.
(see Figure 6).   The upper  and lower  composite samples at  this  zone
confirmed that the water  coming from  above  and  below was of lesser VOC
concentration than the water produced at zone 3.            '
     Zone 4 was  the zone of highest concentration for  1,1-DCE,  1,1,1-TCA
and CCL4.  The upper composite  sample  confirmed  the  presence of  the more
heavily contaminated water from zone  3,  and the  lower  composite  showed
the presence of  less contaminated water below zone 4.
     The zone 5 upper composite sample confirmed the presence of  the more
highly  contaminated  \vater coming  from zone  4.  The  lower composite,
however, showed  less contaminated water coming from  below zone 5.   Since
the Isolated sample from zone 6 was actually higher  In  VOC concentration
than the Isolated sarple from zone 5, It can be concluded that more water
(at a lower concentration than zone 5) must  have entered the wel1 between
zone  5 and  zone 6.   This may account  fcr some  of  the  missing  well
capacity discussed earlier.
     The zcc-e  6  upper composite sample  confirmed the presence of lower
concentration water above the zone.  The lower composite sample was equal
                                    27

-------
             '   'In  concentration to  the  Isolated  sample.   This,  together  with  very
           :  -  .'similar specific capacity data for the  Isolated and  lower zone (0.27 and
                 0.22), Indicated that there were no more water producing zones below zone
    .   -  :••.-.:-;•.-,•'6.'; ••'.; •   -   .-'•'   ••           .   .   .   •   •   .-..-•    -      .
                      The well  characterization of well  L-8 has  Indicated that  casing,
                 grouting or packing off  a  portion of the well would not  be an effective
         — "-.'•    means of Improving the quality of the well,  because the contamination was
                 entering at many different points.   A well of this type would  require
               .  treatment other than 1 solat ten of the contaminant  entry zone.
          '..-.>   .    The Information gathered  by this well  characterization was  used In
                 designing the  In-well  aeration experiments  to  be  performed.   Further
                 explanation of how this Information was used can be found In Section *ป.

                 PUMPING TEST               '                        :   .          '-' -: .;~:  '.

ซ?-)•       .            Traditional  methods of well characterization often  Include  pumping
|;j            - tests.   Pumping  tests  can be  used  to  determine well  efficiency  and
jฃ;"'j              long-term expected  yield.   Water  quality samples  taken during  pumping
                 tests can be  used to establish  long-term trends  In  quality  as  well  as
                 provide a representative sanple of nearby aquifer  conditions.
                    .  A pimping test was performed at well L-8 to further characterize the
                 well and provide Information about the nature of VOC contamination In the
                 vicinity of the well. It was desirable to know how the  VOC concentration
                 would change with time, because  each  In-well aeration test took one full
                 day and was, therefore, performed from a resting  (non-pumping) condition
                 of the wel1.
                      The  test was  conducted  over  a  period  of 5  days  beginning  on
                 September 20,  1982.   The pumping  rate, was  held  constant at  50  gpm and
jj.-.               standard pumping'-test procedures were followed (25,26,27).  Data from the
                 test are found In Figures 8 and 9.  Results of the test Indicated that
                 the  aquifer  surrounding   the  well   was  not  uniform.   The   average
                 permeabilities  of  the  aquifer  appeared  to  Increase,   then  decrease
                 away from the well.   This could be seen  by  the  changes In slope of  the
                 drawdown curve  (Figure 8).  The  starting  water  level  was 21.5  ft  below
                 the top of the casing.   This  dropped  15.1 ft, to 36.6 ft  after  91*  hours
                 of pumping at 50 gom.
                      During  the  purplng test,  samples were  collected periodically  for
                 volatile organic analysis  (see Figure  9).  The major contaminants showed
|_:               similar trends of decreasing within the  first 0.2 hours of punplng then
J*V               gradually  Increasing for  tho remainder  of  the  test.  TCE  snowed  the
                 greatest change, dropping from 720 ug/L to 410 ug/L after  0.2  hours, then
                 steadily rising to 1,190 ug/L by the end of the test.
                      The nature of the change In the VOC concentration  suggested  that the
ฃ= j               sources of contamination were  relatively near the well.   The decline In
                 concentration during the early period  of drawdown Indicated that  the cone
                 of   Influence   spread  Initially  to  areas   that  were  not   severely
                 contaminated, thus causing a dilution  of  the  contaminants  that enter L-8
                 under  natural  or  non-pumping  flow  conditions.   After   0.2  hours  the
                 contaminant concentration began to rise due to the spread  of  the cone of
                 Influence Into the  contaminated  areas.  After approxlnately 30  hours of
                 pimping, the area contributing  contamination.was completely engulfed by
                 the  cone  of   Influence  and  the  rate  of   Increase   In   contaminant


                                                     28

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 -10
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 -15
 -16
                                  RATE = 50 GPM
                                  ElAPSED TIME = 94 MRS
TOTAL DRAWDOWN = 15.1 FT
                                              i
                                              2
                                                    I
                                                   4
                                          LN TIME (0 TO 94 HOURS)
                        Figure 8.  Well  L-8  water level  dra^vdcjwn during pumping test
                                   phase of  well characterization.
                                                           N.
                                               29

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                           Figure 9.  VQC concentration changes with time during pumping
                                      test ef well L-8.
                                                   30

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^^"concentration began to lessen.
  >;!.>:   .This  purplng  test   Indicated  that  large  variations  In . raw water:
..!. •'^concentrations could be  expected over apy single day of  In-well  aeration      ...'.•%.'.-'-.•'
  ;;: testing.   Because  of  this,  It  was  necessary  to monitor  raw  water      ^  ,  \,^;
  '^.concentration carefully during all phases of the testing.               ;,      .. !   '/c

   .' ;,  ;.   -;"/'; -; ^ ='^-:      /': 'V" \'1-

 .*.-     A  review  of historical  data for North Perm Water Authority's well
 -.<• L-8  showed It to be Contaminated with  a  variety of VOCs,  six of  which       -.  :
  ;  were  found at  high enough concentrations  to  be  used for this  study.           ;.;
'"'.,"  These compounds.of  Interest were TCE,  PCE,  VC,  c-l,2-DCE,  1,1,1-TCA  and        '- '  "|
     CCL*t.  When the  contamination was discovered the total VOC  concentration           ^<
 .-•'.:• was approximately 1,000 ug/L.                     .            :        •    •     '.    '.'i
"-•-•'.:      The  Inorganic quality of  well  L-8  was typical  of the  Brunswick           *:.-;
..formation.  It was  hard and  slightly alkaline,  with higher than  average             :'
     chloride levels.                            •-';'                  ,         :'•'•.--.•'•_••-'••"    -*!
        .  Well  logging,  performed by  the U.S.G.S., Identified  seven  potential       .    ';. "
   '..water  zones of  entry  Into  the well.   This   Information  was  used  to    '•••.'- /x.
".     determine where  to  place straddle packers  used  to collect VOC  and  water       .     .
     quality data for each zone..                                            .            .  ':J
          The straddle  packer testing of the  seven  zones  Identified by  the             ':
     U.S.G.S. accounted  for  approximately 81%  of  the well's total  specific           . H.
     capacity; .therefore,   the  remaining  19%  of the specific  capacity  was           ; •..
     contributed  by  zones  not  Identified  during   the well  logging.   In            <:
     addition,  two  zones  Identified  as potential  water   producing  zones
     dewatered almost Irmediately  during packer testing.
          VOC concentrations were  different for each  of the zones tested.  The
     two  most heavily  contaminated  zones were  also  the  two largest  water
     producing zones.  These zones were located at 70 to  89 ft  (zone  3) and at
     121 to  140  ft  (zone 4).   Zone 3  contained  the highest concentrations of
     the  major  contaminants  (TCE, c-l,2-DCE and  PCE) and zone  4 showed  the
     highest concentrations of the minor  contaminants (1,1-DCE,  1,1,1-TCA  and    .        '.
     CCL*O.   The Information  gained  during  the packer  testing was used  to
     determine the depths at which to place the  In-well aeration  equipment.
          The open  borehole  pimping  test showed that VOC  concentrations  at             ;
     well  L-8  changed  considerably  with  time, and that  the  changes were        .
     especially significant, because the in-v.-ell aeration testing would all be
     performed  during this early  part of the  punp  curve.   Because  of  this;
     very frequent  raw water sampling was designed  Into the  In-well  aeration             .:
     testing.                            .                             .         .            ,
                                          31
                                                                                           .

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                 5Sฃซea3Sปฃs3SSE^s
                                SECTION 6

                          EXPERIMENTAL DESIGN
    ,the  experimental  design  for this  project was  developed based  on
Independent  and dependent  variables.   The  Independent  variables  were
experimental  variables  that  were  set   In the  field.   The  dependent
variables  were  data which  were  obtained  by  setting  the  independent
variables.  The dependent variables were, In some cases, calculated (e.g.
horsepower) and  In other cases were measures of quality changes (water or
air) which occurred as a  result  of varying the  Independent  parameters.
Table 7 lists these  Independent and dependent variables.
     Air flow rate was an  Independent  variable.   The  air delivery system
used  to  control and  measure  air  flow  rates throughout  the  In-well
aeration  experiments Is shown  schematically In  Figure 10.  The system
was mounted on  a 4  ft x 6 ft  plywood  board and was  located on the well
house wal 1 approximately *t ft from the well head.
     As can  be seen In  Figure  10, the  air delivery  system was  divided
Into two  air flow pathways.   Side A was used for the air  lift purp and
Side B was for the sparger.
     The  source of  compressed air  was  a gasoline  powered  Schram  Air
Compressor capable of delivering 100 ps*  of air to the In-well  aeration
system.  This was sufficient  for the depths at which work  v/as performed
at well  L-8,  but wells  of  greater depth  would require a  more powerful
compressor.
     A pressure  gauge  (Gl) measured the delivery air pressure  from the
compressor.  Each pressure gauge was mounted with  a test tee  to accept a
calibrated  gauge by way of a  quick-connect fitting.   All gauges  were
checked against  the calibrated test gauge  at  the start of each  testing
day, as well  as periodically during testing.   Fol lowing gauge Gl was a
thermometer  (Tl)  used  to  measure  the  temperature  of  the  Incoming
compressed  air.   Next there  were two filters In  series  (Fl  ฃ F2)  to
remove oil and water vapor and partlculates.  Fl was a Deltech 810 series
filter and F2 was  a Fine  AIre glass  fiber coalescing  filter.   Another
pressure gauge (G2)  followed the filters.  Gl and  G2 were used to monitor
pressure drop over  the  f'lters to observe  any  possible  filter clogging.
After gauge  G2 the   air  delivery  system split  Into side A (for  the  air
lift purp) and side  B (for the air sparger).  Ball  valves (BV-A and BV-B)
were used  to turn either side on  and off.   The  ball valves  were followed
by pressure  reducing valves  (P-A and  P-B)  to  control the amount of  air
pressure at the rotometers.  Three Brooks rotometers were used.   Rl-A and
Rl-B were both  calibrated from  zero to  sixty  cubic  feet  per  minute
(cfpm).  Rotcmeter  R2-A'was calibrated  from zero to six cfpm,  and  was
used only during the lower flow rate portions of air lift pump efficiency
                                    32

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                                TABLE 7.  GENERAL EXPERIMENTAL DESIGN
              -INDEPENDENT VARIABLES
              VARIABLE                 RANGE
              Air flow rate      .      0-116 cfpm

              Footplece Configuration  large/small
              :. , •,.;..;•_•..; .     ,   .    bubble
              Depth cf Sparger         130 ft,200 ft,
                                       280 ft
              Depth of Air Lift Pump   130 ft, 200 ft
                                       •280 ft
              Depth of Electric Pump   200 ft
              Pumping Water Level
ft - 70 ft
DEPENDENT VARIABLES

VARIABLE           RANGE
Water.flow rate   . 20-100cfpm
Submergence        50-75%
Water Horsepower   0.5-1.7HP

Air Horsepower     0-10HP
  (adlabatlc)
Required Com-      0-15HP
pressor HP
Estimated wire-to-water
  efficiency       0.2-^0%  .
Cost to Compress
  Air
Raw Water Quality   organic
  Cprlmary)         removal
Treated Wtr Quality organic
; (primary)         removal
Raw Water QualIty   pH/DO bact
  (secondary)
Treated Wtr Quality pH/DO bact
  (secondary)
                                                         Air Quality
                                   OrganIcs
                                   In air at
                                   wel1  head,
                                   weir box G
                                   20 ft from
                                   weir   box
              testing.   Another pressure  gauge followed  the  rotcmeter  on each  side
              (Gl-A  and Gl-B)  to  determine  air  pressure at  the  rotcmeters.   These
              gauges  were  followed  bv  thermometers  (T-A  and  T-B)  to  measure  air
              temperatures  at  the rotometers.  Rl-A,  R2-A,  Rl-B, Gl-A, Gl-B,  T-A and
              T-B were used to  measure the Independent variable of air flow rate.   Air
              pressure, and  temperature at  the rotometers were necessary to correct air
              flow rate  for deviations from  the rotometer calibration temperature and
              pressure  (see Appendix A).   Next,  there  were  gate valves  to precisely
              control  the  air  flow rate  through  the  rotometers (GV-A and  GV-B).
              Finally pressure gauges G2-A and G2-B were used to measure the actual sir
              delivery -pressure  to the  well.  After these  gauges,  flexible  rubber
              compressor hoses  were  used  to connect  the  air  delivery  system  to the
              equipment In  the well by way of quick-connect fittings.
                   One independent variable was the footplece configuration for the air
              lift pimp  and the  air sparger.  Early  research  (5) had shown  that the
              footplece configuration of the air lift pump could be varied considerably
              without altering the pumping efficiency.  The experimental design
                                                  34

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             described here was derived to test whether  altering the footplece of the
             air lift  pump could  change VOC removal efficiency.  Varying  bubble size
             In diffused aeration affects the organic chemical removal efficiency C28)
             and^ bubble size  Is   Important  In rrodel Ing  aeration treatment  systems.
             In  fact,  the  need  to know  Cor at  least  predict)  bubble  size made  It
             .difficult to model an In-well aeration system.   The bubbles could not be
             measured, and the flow of the water within the well was unknown.         ;
             Bubbles may have  coalesced,, been pulled Into the  pump  or even heve left
             the  borehole  through  fractures before  reaching  the  puop.   Because  of
             this, the data gathered during  In-well aeration testing Is site-specific,
             and Is not useful to predict specific behavior In another system.
                  The two air  lift pump footpleces chosen for this  study provided two
             different bubble  sizes.   It  was hypothesized that  smaller  bubbles would
             provide  a  greater,  air-to-water  surface   Interface area  which  could,
             therefore,  Increase  organic  removal   efficiency.   It was known  that the
             device to .reduce  bubble size would  also  Increase head loss  and be more
             expensive  to  operate.   One design   Introduced  air Into   the  footplece
             through  a simple open pipe configuration  Csee  Figure 11).  This open
             pipe  footplece was  to produce  large bubbles as compared   to  the  second
             footplece, which  Introduced  air through a diffusing device.   The device
             used was  a Pearl comb air  dlffuser,  manufactured by FMC Corporation for
             use  In aeration basins.   It  resembled .an aquarium stone,  producing very
             small bubbles.   The  air  sparger footplece was  also tested.  The first
             sparger  configuration was a  simple,  open  PVC  pipe   to   produce., large
             bubbles  Csee   Figure 11).   The  second   configuration tested  had  a
             Pearlconb aerator attached at the base of the sparger.
                  The next  Independent variables were the depths at  which the air lift
             pump and  sparger  were set In.the well.  Three depths were  chosen, based
             on  the  VOC  and  water  zones  of  entry  determined   during  the  well
             characterization  procedures   Cdlscussed   In   the  previous  section).
             The first depth chosen was 130  feet.  All  depths  were  measured  from the
             90ฐ bend  In the eductor pipe at the wel'. head, to the top of the air lift
             pump,  electric  purp  or   sparger  footplece.   The  130 foot  depth  was
             selected because, based on the  historic purplng  water  level at well L-8,
             It was likely to provide 65% submergence for the air lift purp, which was
             reported  In the 1iterature C5,  29) as the  most  efficient submergence for
             operating an air  lift.-pump.  This depth was  also slightly  belav the most
             heavily contaminated zone of water entry Into the well.   The second depth
             chosen was  200 feet.  This  setting  was below all  of  the  major VOC and
             water zones of entry.  The third depth setting was 280  feet, which was 10
             feet  above the  bottom of the  well.   The 280  ft  depth  was chosen  to
             maximize aeration contact  time  in  the eductor when air lift pumping, and
             to maximize countercurrent stripping by the sparger  In  the well borehole.
             The 200  ft  depth would do the  same  to a lesser  extent, and  because the
             cost to  compress  air  increased with depth,  the 200 ft  setting  would be
             less  expensive than  280  ft.   Operating  the air  lift  purp at  depths
             greater than  130  ft would  Increase costs due to submergence greater than
             the optimum of 65%.   Testing would show whether the  Increased costs would
             pay off In Increased VOC removal.
                  A 12-member  matrix  of equipment configurations was devised for the
             three chosen  depth  settings Csee  Figure  12).   The  entire matrix  was
             examined for the air  lift pump combinations.  After examining air lift
                                                 35
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;  AIR  "LIFT PUMP
  .-:.'" OPEN PIPE
  (LAR6E  BU65LE)
                             AIR  LIFT PUMP
                             . PEARLCCM5
                            (6MALL6UBBLE)
•   SPARGER
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                             (6MALL 5UBBLE)
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Figure 11.  Diagram of air lift pump and sparger configurations
         for footpiece testing.
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              Figure  12.   Matrix of depth settings for air lift pump  and sparger
                          during in-well aeration testing at well L-8.
                                             37
                                                                                                   H
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-------

'f:j    -.   .  punp results the electric pimp testing matrix was extracted as a  subset
•':;..'       of the air lift  punp matrix.    "
C   ;   . •   . '     Another Independent variable was the  pumping  water level.  Under set
;         .   conditions,  the water level while  purplng will vary tremendously  during
1         ;   the course of the year.  This  Is caused  by seasonal rainfall  conditions
|.   '.. ••-.'••;   giving the aquifer differing static water levels  (the water  level  In the
!.-..   well when not purplng).  On a small scale, when the pump  Is  first  turned
;,-,."        on, the water . levs!  will drop  from  the static  level  to  the pumping  level.
!   .  .  .  -   At well L-8 this takes at  least 90  hours (see  results of  pumping test at
• .;••,-.".:    " •  L-8, Section 5).  Because  of resources the aeration  tests were not  rxai
\,'\         this long In each configuration,  so the pumping water  level  was changing
I            with drawdown during the testing.
i         '       In  earlier tests  the water   level  was  measured  by  dropping  an
s-"-          electrical  conductance probe  down  a 1/2  In  plastic  pipe  In  the well.
|.'. •          When  the  probe  encountered  water, a   circuit  war.   completed   and  a
ฃ-..•• .. .    deflection was  observed  on a conductivity scale at  the surface.   The
:"-           water level  was  measured directly from the length of line  In the well  at
'e            the point where the deflection  occurred.   This method was  found to  be
1:           faulty when air was being  Introduced Into the well  through  the sparger.
'.'••          In certain configurations  (sparger adjacent to or  below the  probe  line
r           pipe), the plastic probe  line Itself acted like an air  lift  purp eductor
'            and water was air lifted up through the probe  line pipe.   To  correct  this
•          .  error. In later tests,  a 3/8 In plastic line was dropped down the well  to
;            a  known  depth (275  ft).   A  small  air compressor was  used  to Introduce
            Just enough air  Into this plastic line to  displace the  water  In the line.
            This air was  carefully controlled  so as  to be negligible In  comparison
            v/lth the amount  of air flowing during aeration testing.   The water level
            was then calculated  from the amount of pressure required to Just displace
            the water In the plastic line  (see  Appendix A).               -
                 The Independent variables thus were all direct measurements made In
            the field.  An example of the data collection log may be seen In  Figure
            13.
'.                 The first dependent variable was water flow rate.   This  was measured
            by passing  the  well discharge from the  eductor  through  a  v-notch  weir
            box.  The box Is shown In  Figure l*t.  It was made of stainless steel  and
•     :•      was located outside of the well  house.   The v-notch was  90  degrees.   An
:            observation well was attached to the side of the weir box.   The well  was
;            an 8  In  pipe set up vertically with a metal plate welded to the bottom.
            A  smaller pipe allowed water to  flow from the box to the well.  In  this
•  •          way, the water level In the observation well was the same  as  the level  at
;            the v-notch.  A water level recorder was  set  up on the observation  well
            to provide  a  continuous  record  of water  level at  the v-notch weir.   A
            transparent Tygon  tube was  attached to  the  observation well with  an
:            adjacent  measuring tape to obtain  direct  readings of water  level   at  the
            v-notch.   Water flow  rate  calculations  from a 90ฐ  v-notch are given  In
            Appendix A.
                 The weir box  served  a second purpose,  aside  from water  flow  rate
            measurement .  It was  also  the gas and water  separator during aeration
            experiments.  The water discharged was milky  white with bubbles  during
            experimentation  when the air  sparger was  being used.   The open weir box
:            provided a place for the bubbles,  as well  as  the  VOCs to be released to
;     ..       the atmosphere.   The  water was  clear of bubbles before  It reached  the


;                                                38

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                                                        WEIR  6OX
Figure 14.  V-notch weir box used as air-water separator  and  to measureiwater flow
            rate.   Treated samples were collected at the  v-notch,  water spilled  •
            into the  lower box, then went to waste.     ,       .'"••••    .      .   .'.  <••
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           v-notch (VOC sample collection point).
          ....    The dependent variables  of  submergence, horsepower, efficiency and
          ''cost'were calculated from the  Independent variables.   See Appendix A.  .
          .".    Primary and  secondary  water quality  parameters  were determined by
          : samplIng.and analyses.:- During air lift pump testing the raw water sample
           was collected from a small  Cl HP), submersible pump which was located at
           the .entrance to the  air lift pump footplece.  When  the air sparger was
           not being used,  rew water could be collected from this point at any  time.
           When the air sparger was being used,  the raw water sample had to be  taken
           before the sparger was  turned on,  or the  sample col 1 ected at this  point
           would be aerated and not representative of the raw water.  Each time the
           sparger air flow, rate  was changed, the sparger  was  first  turned off to
           allow the air to clear from the well.  The well wss declared free of air
           from  the sparger when  the  raw water  dissolved oxygen  concentration
           returned to background  conditions defined at the  start of testing, before
           any air had been Introduced  to the sparger.   It typically took 45 minutes
           to one hour to clear the well  between sparger air flow rate  changes.
            .    The primary water quality parameters examined were  the six volatile
           organic compounds found  In well  L-8  In high enough concentrations to be
           statistically compared  In  raw and  aerated samples.    The  samples were
           collected and analyzed  according to EPA method  502.1  (30), which  Is a
           purge  and   trap   gas  chromatographic  procedure  using  the  halogen
           specificity of the Hall  Electrolytic Conductivity Detector (HECD).  The
           gas chrcmatograph used was  a  Varlan 4600 with a Vista 401 data system.
           The purge  and trap  apparatus was  a Teknar  LSC-2 with the  Tekmar ALS
           autosampler.  The quality control  program  was developed based on Method
           502.1  and  the  literature  (31).   Gas chromatographic conditions and
           quality control  procedures are given In Appendix  D.
                The secondary  water quality  parameters were pH, dissolved oxygen
           (DO)  and bacteriological  quality.   The   pH and  DO  measurements  were
           made In  the  field,  Itrmediately after the  sample was  collected.   The pH
           was measured  using  a  Corning portable pH  meter, Model  4.   Dissolved
           oxygen was measured with an  Orion DO probe,  model 97-08-00.  The
           bacteriological  samples were analyzed by both the heterotrophlc plate
           count and the R2A agar  plate count methods  (32).
                The  treated  water  quality,  both   for  primary  and  secondary
           parameters,  showed water quality  after In-well  aeration treatment under
           the conditions  represented  by the  Independent  variables.   The treated
           water samples were collected from  the v-notch of  the weir  box.   The
           analytical  methodology  was the same as discussed above for  the raw water
           samples.
                The final  dependent variable  was air quality.    Air  samples were
           taken In the well house, over  the weir  box and 20 ft  from the weir box.
           Two methods were  used  for examining  the  air.  The first Kas  to pull a
           known amount of  air through  a tenax/sllica  gel/charcoal  trap  using an
           Industrial  hygiene sampling pump.   The trap was capped and returned to
           the laboratory where It  was desorbed by the  purge and trap device Into
           the gas  chromatograph  for analysis.  Two  traps were  used  In  series to
           monitor for sample breakthrough  from the  first trap.   The second method
           used to monitor  the air was  by the on-slte  analysis using an HNU portable-.
           photolonlzatlon    detector.    Both  of  these   methods   are  described
           In more detail  In Section 12.
                                              41

-------
                                                                                                /\

                                  •.";.'.'.'       SECTION 7;
                                    PRELIMINARY FOOTPIECE INVESTIGATIONS
                  AIR LIFT PIMP FOOTPIECE TESTS  - PROCEDURES

           -.           Footplece configurations  for both the air lift pump and the In-well
                  diffused aerator  (sparger)  were  Independent  variables as  discussed In
                  Section 6.   The preliminary  Investigations tested two types of footpleces
                  for the air lift pump and two  types of footpleces for the sparger.  These
                  experiments were  also  used to  develop operating  techniques  and  gain
                  experience  In using the  air lift  punp, both with and without a sparger.
                  Although air lift pumping had  been used at North Perm Water Authority In
                  the past, personnel who were  familiar with air  lift  pump operation had
                  retired.                                                         .
                       The tests run on  the air lift  pump,  without the sparger, were also
                  used to develop air  lift pumping efficiency curves.  The  air lift pump
                  and sparger were both  set at  a 130  ft depth In the well.  All equipment
                  depths  were  measured  from  the  top  of  the  air lift  pump  or sparger
                  footplece to the center  of  the 90ฐ  bend of the eductor (water discharge
                  pipe) at the v/el 1  head.
                       The a!r  lift punp footplece used  for  preliminary  testing was  a
                  combination of the two footpleces to be tested.  This design v/as used so
                  that the air lift pump  would not have to  be removed from  the well to
                  change  footpleces.    Installing  and   removing an  air  lift  pump  was
                  comparable  to performing  similar  operations  for  an electric submersible
                  pump In terms of labor and time required.  Figure 15 Illustrates the air
                  lift punp  design  used for  the preliminary footplece testing.   The air
                  lift purp footplece was made of 4 In diameter  steel pipe.  The steel pipe
                  was tapped  to accept 3/4  in fittings  for the electric submersible sample
                  pump, the air  feed  line ending with  an air diffuser, and  the  air feed
                  line which  ended as  a simple  open  pipe.  The  air lift  footplece was
                  attached to the 2-1/2  In steel eductor pipe with reducing fittings.  The
                  air lift punp was then lowered Into the well  by  attaching 10 ft lengths
                  of 2-1/2 In steel pipe for  the eductor and 10 ft  lengths  of 3/4 in PVC
                  pipe for  the  sample  pump  discharge, diffuser  air  line  (small  bubble
                  footplece)  and the open pipe air line  (large bubble footplece).
                       A 1/2  In PVC pipe was  lowered  Into the well  to allow a water level
                  measuring probe to be  used.  This pipe prevented the  water level  probe
                  wire from becoming entangled with the  rest of  the equipment  In the well.
 *!.'.'                   Each of the PVC  pipes were color  coded and labelled at the well head
 |l j              so they could be distinguished. A color code  diagram was drawn and kept
 |> ;              at the wel1  head for  reference.  The color coding  Is shown  In Figure  15-
   i                   The footpleces were chosen  to provide different bubble  sizes for


   I        • '    .             .                       42

K I                                                             '     .

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gure 15. Diagram of in-well aeration equipment used . • . |
during air lift pump and sparger footpiece . . 1
testing. j
43


-------
 \
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 /~"':-x-
  aeration.  The-tests were to determine whether changing bubble'size would
 : significantly affect VOC  removal  or the cost to compress  air because of
  Increased  hand loss  provided by the  diffused aerator.   Based on  the
  literature,  changes  In air  lift  pumping  efficiency  (amount  of  water
  pumped for amount of air added) were not  expected with changing air lift
 .. punp.footpleces.
 '.'=_.-•'  . 'It  Is important to make  a semantic distinction between a ''test" and
  a "run".  Four tests were performed during preliminary footplece studies.
  A.test  was  a  series of  runs, with one  depth  configuration of In-well
"  aeration equipment per  test.  For each run,  air flow rates were altered. -
  For example, for a particular test the air lift pump and sparger were set
  at 130 ft  In the well.  These depth settings were  rปt changed during the
  test.   For  each  run during  the  test,  a different amount  of air  was
  delivered to the  air lift punp and/or  sparger.  Also,  during certain of
  these preliminary  tests the footplece configurations were different  for
  different runs within a test.
       Preliminary  Test  ftl  will   be   described In  detail,  as  It  Is
  descriptive  of the procedure  used In other tests.   The air lift pump was
  operated  without  the  sparger.    Air  was first delivered  to the  large
  bubble  air  lift  pump footplece.   The range of  air delivery  rotometer
  settings were from 5 to 116 cfpm.  The same air flow rates were then used
  with the small bubble footplece.
       The portable air compressor was started and the output xvas  connected
  to the air delivery  system (described  In  Section 6, see Figure  10).  The
  first air  flow rate used  was 6  cfpm.  The  rotometer was adjusted  to 6
  cfpm and the air lift  pump was  allowed  to  run for 5  minutes.  After 5
  minutes, a series of readings were taken of the water  level, water flow
  rate, and the various gauges  and  thermometers.   If  the rotometer setting
  was drifting, It was adjusted at the 5 minute reading.  The air  lift pump
  then ran for 10 more minutes  to  give a total run time of 15 minutes.  At
  the  end of  the  15  minute run  the readings were  taken  again and  VGA
  samples  were collected.  This 15  minute  run procedure was  repeated for
  26,40,58,78,96  and   116   cfpm  rotometer settings.   The  entire  test
  consisted of 14 runs; seven with the large bubble air lift punp footplece
  and  seven with the small  bubble  air  lift  pump  footplece.  The  basic
  procedure of using  15 minute  run  times with  readings at 5  and 15 minutes
  and  sampling at  15 minutes was used  throughout the rest  of  the In-well
  aeration testing at well L-8.
       During  the first air lift punp footplece test  It was discovered that
  the water level at the v-notch of the weir box was difficult to determine
  directly.  Also, the original rotometers  for measuring  air delivery were
  difficult to adjust at low flow  rates.  Because of these difficulties,
  the air  lift punp  efficiency  data for the first test were questionable.
  The  weir box was  modified to  include a direct reading tube  and  water
  lievel recorder (see  Section 6 for details).   A  new rotometer, calibrated
  from 0  to 6 cfpm, was  Installed for  use for the very  low air delivery
  rates.  Preliminary Test %l was then repeated, using these modlfIcatlons.
  The  modifications  were adopted  for use during the rest of  the In-well
  aeration tests at well L-8.
       After examining the  air  lift pump  operating  data,  It  was decided
  that the cost to operate the  air  lift  pump could be reduced by  enlarging
  the size of  the air  delivery  line from 3/4  In to 1  In.   A third air lift
                                                                                                          n
                                                                                                          $
                                                                                                          I
                                                                                                          I
                                                      44

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-------
pump'preliminary  test was run using  the new, larger air  delivery line.
The large bubble footplece was used for this test.      .,      -.:   •     .  f

AIR LIFT PUMP FOOTPIECE TESTS - RESULTS AM> DISCUSSION        .   :-X;, ^

T     In terms of  pump operating parameters, the  air  lift  pump footplece
tests confirmed what  had been predicted frcm the literature.  Figure 16
Illustrates changes  In air lift pump operating air pressure  and  cost to
compress  air for  the  three  preliminary  air lift  pump  tests.   Higher
operating  pressures  resulted  In  higher operating costs.   Costs shown
here were only  the costs to compress air.  They  do not Include costs of
disinfection, repumplng after a  clear well, operation and maintenance,
etc. (see  Appendix A).  As expected,  the  operating pressure of  the  air
lift pump  equipped with  the  restricted opening,  small  bubble footplece
had the  highest operating pressure  and therefore the  highest  operating -
cost.  The  maximum air pressure  for this configuration was  83 psl  with
a  maximum cost of 29.5$  per  thousand  gallons.   The  maximum  operating
pressure for the  large bubble  air lift pump footplece  with a 3/4 In air
line was  68 psl, which  produced  a cost of 25.7$ per  thousand gallons.
The large bubble  air  lift pump footplece,  with the 1  !n air  line, had a
maximum operating  pressure of 54  psi with a cost of 20.4$ per thousand
gallons to compress air.   Pressure differences were most apparent at the
higher air del Ivery  rates where  friction  loss was greater.   Since  the
most efficient  operation of the  air lift pump was at a  lower air  flow
rate where  operating  pressure  differences were  smaller,  the choice  of
footplece configuration was not  found  to be critical  In   terms  of  cost
when designing an air  lift pump.
     Figure 17  Illustrates the results of the preliminary air  lift  pump
tests  in  terms of pumping efficiency  (wire-to-water  efficiency).   The
shape of  the  pumping  efficiency  curve  followed  that predicted frcm the
literature  (5,29).    The  curve   sharply   rose   to  a   maximum  pumping
efficiency of  30-35%, then gradually fell as more  air was  added.   The
maximum efficiency  coincided  with an  air-to-water ratio  range of 1.1:1
through 1.4:1.   The shape of  the curve was  because  of slippage  In  the
eductor  at  higher  air-to-water  ratios.   (At higher   than  optimum
air-to-water ratios, the  excess air  moves  faster  up the eductor than the
air/water mixture  Itself.  This phenomenon Is defined  as slippage.)   The
depth  setting  of  130 ft  for these  preliminary   tests was  designed  to
provide 65% submergence for the air  lift pump, which  was the theoretical
optimum  submergence  In terms  of air  lift  pumping  efficiency  (5,29).
Because of this,  the  pumping efficiency maximum  shown In  Figure  17  was
the best efficiency which could be expected for the air lift pump used In
these studies.  The 30-35% efficiency  was consistent  with observed  air
lift pump efficiencies In the literature.
     The data frcm the air lift  pump footplece   test also confirmed  the
literature wherein the two footplece configurations examined  showed  very
little difference In air lift pump efficiency  (see Figure  17).  Changing
from the 3/4 in to 1  In air delivery line  did cause a slight Improvenent
In air lift pump efficiency.
     The VOC  removal   results for  the air lift  pump footplece  tests  are
shown In Table 8 and Figures 18 and  19.  The  figures  represent  data  from
both repeats of the air  lift  pump footplece tests using  the 3/4 In air
                                    45

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OPERATING AIR PRESSURE (pal)
                                   In LAROE BUBBLE
                              COST TO COMPRESS AIR (CENTS/THOUSAND OAL)

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                                LAROE BUBBLE
                                                        1 In LAROE BUBBLE
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                                   2O        40        60        BO
                                                    100       120
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                                           AIR DELIVERY TO PUMP - cfpm
                                                                               fi
                           Figure 16.  Operating air pressure and cost to compress air
                                       for air lift pump footpiece tests during
                                       preliminary investigations.
                                                  46
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                                              AIR DELIVERY TO PUMP - cfpm


                             Figure 17.   Air lift pump wire to water efficiency for
                                          footpiece testing.                    ,

JV-'X
                                                      47

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If •
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                                TABLE 8.  VOC REMOVAL DATA FOR AIR LIFT PUMP FOOTPIECE TESTING (AVERAGE OF ALL
                                     '     	LARGE AND SMALL BUBBLE AIR LIFT PUMP FOOTPIFCE TESTS)
AIR-TO-WATER
RATIO	


AVE  %RSD  N


 1.2  9.3  5

 2.4  6.3  4


 3.5  5.1  5


 4.9  0.0  2

 7.0  1.4  2


 8.7  1.1  2

11.1  5.1  5
% REMOVALS


TCE


AVE  %RSD


33.1  19

40.4  3.7


48.5  5.8


52.6  4.7


58.2  6.9


65.1  0.65

70.8  3.3
FOR VOCs

   PCE


   AVE  %RSD


   40.4  14


   52.2  4.1


   02.0  4.7

   66.2  1.6


   71.4  5.7
c-l,2-DCE

AVE  %RSD


26.5  33 -

26.7  2.1


35.5  7.3

37.2  16


43.3  9.5
1,1,1-TCA


AVE  %RSD


48.3   19

56.7   2.1
                                                                                                  1,1-DCE
                         VC
                                                           76.7  0.74   48.7 . 0.60

                                                           81.1  2.8    55.2  7.5
             AVE  %RSD   AVE  %RSD


             57.6  11    54.8  22 ',


             67.7  2.1   72.1  0.81


64.9   9.9   74.7  5.2   76.6  4.6 .


73.8   1.4  . 80.8  0.5   82.6  3.3


78.9   5.9   85.5  0.1  .86.8  2.0


82.0   1.0   87.0  2.4   89.3  0.80


85.3   2.4   89.9  1.2   93.6  3.8

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                     3/4 in LARGE BUBBLE FOOTPIECE a
               3/4 in LARGE BUBBLE FOOTPIECE (DUP) *
                     .  1 in LARGE BUBBLE FOOTPIECE *
                     3/4 in SMALL BUBBLE FOOTPIECE ^
               3/4 in SMALL BUBBLE FOOTPIECE (DUP) x
        O—1.2— DOE REMOVAL.
                     a          7    .
                     AIR TO WATER RATIO
                                                     11
 1
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Figure 18.  Removal of major contaminants from well L-8.
            during air lift pump footpiece tests.
                        49

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                     9
                                          1.1— DOE REMOVAL.
                                          VINYL CHLORIDE REMOVAL.
                              s          r
                              AIR TO WATER RATIO
                                                              11
         Figure 19.  Removal of minor contaminants from veil L-8
                     during air lift pump footpiece tests.  For legend,
                     see Figure 18.                   .    -
                                •  50

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                                                                   ,_-^_^_^ ^.^

                                                                   '-'••>' -  •'.. .,' ,' '•  ''••'..'..-'.- ""'".•I"-"-}

 line as well  as data  from the  test using  the 1  In  air line.   Visual .      ''„'"'ฃ'''''• 1
 examination of  the  results  Indicated  that  none  of the  configurations     •      ''  j
 tested were"significantly  better or worse  In terms of volatile  organic            V'-l
 chemical  removal efficiencies  with a  ฑ10%  experimental  error.   It  also              1
 demonstrated good  reproduc 1 b111ty where duplicate tests wore  conducted            .'.\j
 and lent  confidence to the procedures.                          •          ,     .;   -'   \?
      The .air-to-water ratios plotted on the x-axes of these figures are            .  }
 averages  of'ratios obtained during the tests for:the same air rotometer  .       . '••:;..-:]
 setting.   A problem with  air lift  punp field work was  that the  same              .j
.rotometer setting yielded different water flow  rates at  different times.  .          .  4
 This could be caused by a number of factors,  but the principal  cause was              ]
 the air lift punp  submergence  changed  constantly  as the water  level was              :.
 drawn  down  during  pumping.    Since  well   water  level   could  not  be    .      •''•'•}
 controlled,  It was  decided to keep  the rotometer settings constant for        '•',    •
 each run  from test  to test.                                                ...*-.-   .J
      The  air-to-water ratio column of Table  8 shows tne  deviations which              -i
 occurred  for  rotometer settings during the preliminary  air   lift  punp              ->i
 tests.  The percent  relative  standard  deviation was the highest  for the           .   .j
 lowest  air-to-water  ratio.    At  these  very  low  air   deliveries  the              <
 air/water mixture  surged  from the  eductor  at  5 to 10 second  Intervals              ]
 causing an  uneven  water  flow.   The  uneven  flow made  It difficult  to             • '\
 accurately measure water flow  rate,  which would account for the  greater             -;"1
 variability In air-to-water ratio at  low air delivery rates.   These  low              J
 air delivery rates  produced air-to-water ratios below 2 to 3 which Is the              j
 theoretical  optimum for air lift punp operation.
      If the air-to-water  ratio  was the only  factor  affecting  organic              ;
 removal efficiencies  Cand  not air  lift punp footplece  configurations),              •
 the percent relative standard  deviations for  the  removal efficiencies              ;
 should be similar to those for the air-to-water ratios.   In most cases  In             . •:
 Table  8,  this  seems to be true,  but  for several  ratios the  data  were              '.
 derived from only two  data points, which diminished confidence In these
 conclusions.  The data for the lowest air-to-water ratio  was consistently
 higher In percent relative standard deviation for the VOC removals  than
 for the  air-to-water r.tlo,   I.e.  the  VOC removal  varied more than the
 air-to-water ratio  at a  particular rotometer  setting.   For  this data,              •
 air-to-water ratio  was probably  not  the only  factor affecting  organic              .
 removal.   Because of the  surging water  flow at the lowest air-to-water          ' -   '.
 ratio, VOC  removals  may have  been affected by  a different,  Inconsistent
 type of air/water Interface In the eductor and the weir box.
      Both the volatile organic  chemical  removal  data and  the air  lift              ;
 punp efficiency  data Indicated  that there  was  no reason to attempt  to
 create smaller  bubbles with  the air  lift  punp  footplece.   It was not              :
 possible  to see what was happening In the well during testing,  but It can
 be assured  that, at that oepth In the well,   In the relatively small              '
 eductor pipe,  the  bubbles rapidly  coalesced.   Davis  and  Weldner C5)      .
 observed  coalescing of small bubbles in  their laboratory tests enploylng
 glass eductors.   For most of  the distance the air traveled In the  eductor             . •
 pipe,   there  likely  was no difference  between bubbles Introduced  by the
 large bubble or  small bubble  air lift  punp footplece.  Because of this,
 and the higher  operating  cost of  the  small  bubble  footplece,  the large              •!
 bubble open pipe air lift  punp footplece configuration was used  for the              •
 rest of the  In-well  aeration  tests.  The 1  In  air feed  line remained  In


                           '      --si               .           -       '•'.           '  ;

-------
             "use because of Its lower operating pressure.       .          .-'.•....,;:,.,"~ \-'•-••;:-.:?%'~l:'^.:..-*••:-%:v>

              SPARGER FOOTPIECE TESTS - PROCEDURES             /      -,.     ;-.:;:  :  ''^ .-•• :^^- V :i V >:

                   two 3A In air sparge lines were lowered Into the well to a depth of    '
              130 ft.  The air lift pump remained In the well at a depth of 130 ft.  In           ..
              contrast to Installing the air  lift pump,  Installing an air lift sparger
             :was a simple task.  The  spargers were lowered Into the well by attaching'          .
              10 ft lengths of 3A  In  PVC  pipe at the  surface.   One sparger ended  In a
              dlffusslon device  to  produce small bubbles, while  the  other was left as
              an open pipe to produce larger bubbles.                                          -    -
                   Preliminary Test ง1 will be described.   It was typical of the other
              tests performed.   The air  lift  pump was operated  at a  rotorneter setting            •-:•
              of 25 cfprn.  This air delivery rate was found to be the most efficient In
              the a*r.lift punp  footplece  tests,  producing the highest water flow  rate
              per unit of air Introduced Into the air lift pump.                 ;   v       .      -
                   The first run of each of the sparger footplece tests  was done with
              the air  lift  pump alone; no air was  being  added  by the sparger.  Next/               I
              several runs were  performed  with Increasing  amounts of air added through            ,   i
              the sparger.   Finally the  air lift punp and sparger were both turned up               I
              to their maximum air delivery  rates  for one  run.  This final  step was               I
              done  In order to try  to get  the highest  possible air-to-water ratio              J .
              without regard to air lift pumping efficiency.                    :                     . |
                   During air  sparging  It was  not possible  to  collect a  raw water            • . .3
              sample, because  the  sample  pump  would  have collected water  which was               1
              aerated by the sparger  (see Figure  15  for sample purp  location).   In               |
              order to collect  raw water  samples between  runs, the  sparger  had to be               ]
              shut down,  then  the well was allowed to clear of  bubbles  while the air               ซ
              lift puip was still running.  The effluent of the sample purp was watched               J
              until  It was  clear to the eye, then the  raw water was  sampled and the               ;
              next  15 minute sparging run was started.   A dissolved oxygen  probe was               :
              used  to  verify the clearing of the  well  Csee Section 6)   The clearing               ]
              process  took  approximately  45  minutes.   During  the   15  minute  runs,               ]
              readings of the  various gauges  and  thermometers, as well  as water  flow              ":
              rates and well water levels, were taken at 5 and 15 minutes Into the  run.               '
              As with the air  lift purp footplece  tests,  any necessary adjustments to            .   ;
              air  delivery   rates  were  made  at  the  5  minute  reading.    Treated  VOA               ;
              samples were collected at the v-notch weir at 15 minutes.                              ''

              SPARGER FOOTPIECE TESTS - RESULTS AM) DISCUSSION                                        *
                                                                                                   '' "  *
                   Sparging  air  Into  the  well  borehole  had  an effect  on  air  lift
              punplng which  can be seen  In Figure  20.  As  air was  added  through the             ::
              sparger, the  amount  of water punped  gradually declined.   This could be               :
              easily explained by re-examining the  operating  principle of the air  lift               '
              purp.   Introducing air  Into the eductor of the  air lift purp created a               i
              density difference between  the water  Inside and outside  the eductor.               !
              This density difference  was  the driving force which lifted the water up               \
              and out of the well.   When  the  sparger  was  In use, air  was being added               ;
              both  Inside  and   outside  the  eductor.    The  density  differential  was               •
              reduced, which reduced the driving force of the air  lift purp.  In Figure               i
              20, the air lift purp was operated at a constant air delivery rate of 25
                                                                                                     •j
                                                                                                      i
                                                  52                                      •'•':
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     100
      80-
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      50

             GPU LOSS WHH INCREASING AIR ID SPARGER
                  i    i    i
                                             8
                                            i    i     r
                                               10
                                                              12
                              AIR TO WATER RATIO
              D   LARGE BUBBLE           +  SMALL BUBBLE
                                                                                  :ง
                                                                                   fel
                                                                                    a
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                                                                             %
                                                                            1
       •'„  Figure 20.  The amount of water pumped by the air lift pump
                     decreased as air was added through the sparger.


-------
'
   cfpm and the amount of water pumped dropped (from.78 to 68 gpm) as the  "
   'air lift  pump  driving force was reduced with addition of air through the
   sparger. '.. ;     :    .•   • -  •   •••-•..       '      .   ..    .: .. v . :\ .  •.;  ;-'>•-. ' :•
    ..  :The  effect of  sparging  on  air  lift pump efficiency could not be
   determined during  the   early  tests  because of  inaccurate water  level
   measurements.   Water  level  wss needed to calculate the pump horsepower
   (see Appendix  A).   When the sparger was operating, the plastic pipe used
   for the water  level  probe was  filled with aerated  water which  operated
   like an  air  lift  pump  Itself,  causing  artificially  high water  level
   readings.   This was  not discovered until  later testing when  water was
   actually  pumped out  of  the well through the water level probe pipe.  The         "."•;   *.;|
   problem was corrected   In  later  tests  and  the  air pressure  method of               ^
   obtaining water levels  was used.   A description of this procedure can be
   found In  Section 6.
    ';   Figure  21 shows the cost to compress air for the sparger footplece
   testing.   The  costs for the air  lift pump In  combination with the  large
   bubble or small  bubble  spargers were nearly  Identical, ranging from  kt to
   13$ per thousand gallons  at  air delivery rates  of  28 to 75  cfpm.   The
   operating pressures  were only  slightly different  for the  two sparger
   footpleces.  The small  bubble sparger footplece ranged from 31* to **3 pslg
   while  the large  bubble  sparger footplece  required  33.5   to  *ป1  pslg
   operating pressure.  These small pressure  differences  between sparger             .  |':
   footpleces  translated   Into  very  little difference  between   cost  to         .      <"
   compress  air for the  two types of spargers.                                ''.-•[
         The  cost  to compress air was similar  for the air  lift  pump  alone               j
   versus the air  lift  pump and  sparger combination.  The  3/k  In air line               •(
   air lift  pump with a large bubble footplece cost b$ to 1H per  thousand               j
   gallons (air delivery of 26 to  77 cfpm).   This compared with  *ป$ to 13*               \
   per thousand  gallons for the air  lift pump and  sparger cont>lnatlon at               \
   similar air  delivery  rates  (28 to 75 cfpm).  Cost differences for the air
   lift pump footpleces became more  apparent at air  deliveries  above 75
   cfpm.   The  sparger was not operated at these  higher air delivery  rates
   because,   at  rates  above  75  cfpm,  water was blown  out of   the  well
   borehole.  This occurred because  the sparger was delivering enough air to
   turn the  entire well into  an air lift  pump, with the borehole acting as
   an  eductor.
         The  VOC removal results for sparger  footplece  testing  are  shown  In
   Figures 22 and  23.   The figures  compare  removals for small  bubble and
   large bubble spargers,   as  well  as the  earlier results  for  small bubble
   and large butble air  lift pump footpieces.
         Apparently, there  was no significant difference  In organic removal
   efficiencies  between  the two   types   of spargers  tested.   The  same
   conclusion was  made earlier  for  the  air  lift  purp footpleces.   The
   figures also show not  only were  the small and large  bubble  sparger VOC
   removals   similar  to each  other,  but  VOC  removal   by the  air  lift
   pump-sparger combination was similar  to VOC removal  by the air lift purp
   alone.   In addition,  the VOC  removal  at the highest air-to-water ratios,
   representing  the runs where the  air delivery  to the air lift pump was
   raised to its  maximum, agree with  removal  obtained by  keeping the air
   lift pump at a constant air delivery rate (25 cfpm) and adding  increased
   alr.to the sparger.   In short,  the preliminary footplece tests  indicated
   that for  a given air-to-water ratio at  a  given depth  In  the  well It did
                                                                                             .
                                                                                            •-i

-------
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      0
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20
19
18
17
16
15
14
13
12
11
10
 9
 8
 7
 6
 5
 4
 3
 2
 1
 0
                 COST FDR SPARGER AND AIR LIFT PUMP COMBINATION
                D  URGE BUBBLE SPARGER
                   SMALL BUBBlf SPARGER
                     \      I      III     I      I      I
               0          20          40         60          80

                          AIR DELIVERY TO SPARGER AND PUMP- cfpm
                 Figure 21.  Cost to compress air for air lift pump and
                            sparger combination during footpiece testing.
                                       55
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                                            KEYl  AIR Urr PUMP ALONK SMALL PUBTO g
                                                  AIR UPT PUMP ALONE LAROZ BUปBLg.
                                                   AIR urr a* LAROS euseuc RPAROK
                                                   AIR UPT & SMALL. BUBBLE
                                    fl
                                                                  C-1.2-DCE
                                                                  PCE
                                               4.         a        a
                                                  AIR TO WATER RATIO
                                                                           to
                                                                                     ia
                             Figure 22.  Removal of major contasinants during sparger and
                                         air lift pump footpiece testing.
                                                      56

-------
p.•'-'-v.."';--"-'--: ';"r-'  .V; >•'.:-. 100 -p	——-
^."•^•J^'^^'io^.   1,1,1-1
"7D--
 00-
 ao
 10
too
                      4O -
                     . SO -
                      ao -
                      10 -
                     100
                      BO -
                      BO -
                      TO -
                      so -
                      BO -
                      4O -
                      SO -
                      ao -
                      10 -
                       o
             -TCA
                                              e
                                                AIR UPT PUMP ALONE 8MAU. BUSBUS — A
                                                AIR LIFT PUMP ALONE LAROE BUBCBLE — *
        ,1,1-DCE
                             AIR UPT fit LAROE BUBOUE QPAROff — a
                             AIR UPT ซt SMALL. BUBBLE BPAROE — -f
        vc
                        4.        a         •        10        12
                           AIR TO WATER RATIO
      Figure  23.   Removal of minor contaminants during sparger
                   and air lift pomp footpiece testing.
                               57


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not matter what configuration of In-well aeration equipment was used,  the
VOC  removals  were the  same.   This held  true for  all  of  the  compounds
except,  vinyl  chloride.    For  vinyl  chloride,  although  the  sparger
footpleces  both  produced  the  same  curves,  and  the  air  lift  pump
footpleces both produced the same curves, the air lift punp by Itself did
not  seem  to  remove  the vinyl chloride  as well  as the air  lift  punp  and
sparger  combination.   Vinyl  chloride  has  the  highest  Henry's  Law
partition  constant  of  all  of  the  compounds  found  In well  L-8,  and
therefore, was the most easily removed.  Perhaps .because of.this  It  was
more sens I Uve to In-well aeration configuration changes. -     ...
    .Table 9  Is a  sunnmary of  the  air  lift  pump and  sparger  footplece
testing removal  data,  In  terms of  percent  relative standard  deviation
(%RSD).  A similar  Interpretation was presented for  the  air  lift  punp
footplece tests without the sparger  In  Table  8.   As was mentioned  In the
air  lift  punp footplece  testing  discussion,  a  given air  lift  punp
rotometer setting did not always give the same water flow rate each time.
This was because of changes such as static and pumping water level  of the
well, which  affected  the operation  of ths air  lift punp.   The  air-to-
water  ratio  coluin  of  Table 9 showed  this  variation.   The  VOC  removal
percentages showed  how  removal  varied  at  these different  air-to-water
ratios.  The removals could be expected to va^y at  least the same amount
as  the air-to-water  ratios, (as seen by the percent  relative  standard
deviation).   If  the  In-well  aeration configuration affected removal,  a
much higher %RSD  for  VOC removals would  be  expected than  that  observed
for  the air-to-water  ratio.   Table  9  did  not  show major  differences
between the %RSD for air-to-water ratios and the %RSDs for removals.   The
exception was In several of the vinyl chloride points, where the graph in
Figure  23  Indicated  a  difference  In removal between  the  air  lift  punp
alone and  the air lift  punp with a  sparger.   Table 9  showed  a  greater
variability In air-to-water ratio and  VOC removal for lov.er air delivery
rates  (also  seen In  Table  8  for the  air  lift punp without  a  sparger).
This could be caused  by variable flow patterns when less  air was being
Introduced into the well borehole.

CONCLUSIONS FOR FOOTPIECE TESTING              ,       '.

     Results of  the footplece  testing for the  air lift  punp  Indicated
that the  small  bubble footpiece caused greater operating  pressure—than
the  large  bubble  footplece,   as   expected.   The  operating  pressure
difference was greatest at the highest air-to-water ratios (5:1 to 12:1).
In terms of  pumping  efficiency,  the most efficient  operation of  the air
lift punp was found to be at a lower air-to-water ratio (1.5:1),  where
the  operating pressure  difference between the punp  footpieces was small.
There was  very  little difference In maxlmun  punp efficiency  between  the
large and  srnal 1  bubble  air lift punp.  The maximum efficiency  was found
to be 30-35%, which confirmed the literature.                   .
     .There was no difference in VOC removal  between the two air lift punp
footpleces.  At the maximun obtainable air-to-water ratio of  11.1 tb-4>
VX  removals  ranged  from  55.2%  for  c-l,2-DCE  (lowest  Henry's  Law
constant) to 93.6% for vinyl chloride (highest Henry's Law constant).
i     The cost to compress air  ranged  from 2<;/l,000  gallons at an alr-to-
v/ater ratio of 1.2:1, to 29.5^, 25.7$,  and  20.k$ per  1,000  gallons  for
                                    58


-------
!     •

1 r~* • "-••'"• ";/•

I K
 t: --t;
                                                                                         N,      ;^
                                                                                                       '' '
                                                                                                           ' ^
TABLE 9.  VOC REMOVAL DATA FOR SPARGER FOOTPIECE TESTING (AVERAGE OF ALL LARGE 8.SMALL BUBBLE

                               SPARGER FOOTPIECE TESTS)

AIR TO WATER
RATIO
AVE
1.8
2.9
3.2
3.8
5.5
7.4
8.6
12
%RSD N
39 4
1
1
5.3 4
0.0 2
1
1.2 2
2.5 4
% REMOVALS FOR VOC
TCE PCE
AVE %RSD AVE
35.3 9.2
39.0 - :
43.5
47.3 4.5
58.6 1.1
' 66.4
66.4 1.1 .
75.6 3.5
43.3
54.1
56.5
61.7
75.1
79.5
. 79.7.
84.4
C-1.2-DCE . 1,1,-TCA 1,1-DCE VC :
%RSD AVE
11.1 25.2
28.6
- . 34.8
3.6 34.6-
0.10 40.6
50.7
0.52 53.0
3.9 59.2
%RSD AVE
8.5 53.6
- 54.5
- '61.1..
2.8. 66.0
0.40 75.6
80.2
2.3 72.8
6.5 85.5
%RSD AVE
10.5 63.0
70.0
- . 75.0
. 3.7 76.9
1.3 79.1
- 80.5
.1.5 72.8
1.0 87.0
%RSD AVE
9.3 , 57.9
.'.'.'- .79.3
'•• - i. 85.6
2.3 86.4
0.60 98.2
- 97.9
3.6 . 97.5
2.9 95.3
%RSD'
. 22.1-
' • -.-••.
• • -."•
.10.5
• 0.53;
' ••• - '
0.79
.. 3.5


-------
                                                                 E2Sฃ
             '" the small  bubble - 3A  In  air line, large bubble -  3A In air line and
               large bubble - 1  In air  line  air lift pump footpleces,  respectively.  The
             .  cost differences  were greatest at the highest air-to-water ratios, where
               the operating pressure differences were the greatest.              '   ..
              .'•'•••' VOC removal  efficiency was greatest at the  highest air-to-water
               ratios and the air lift pump efficiency was  best at a low air-to-water
               ratio; therefore, an air  lift  pump  would  have to  be operated  in an
               Inefficient way In order to use the  pump.for VOC  treatment.  Operation at
               the highest  air-to-water ratios caused the  small  bubble  air lift pump
               footplece   to . be  considerably  more  expensive  than  the  large  bubble
               footplece.    Since there was  no difference In  VOC removal between the two
               air  lift   pump  footpleces,  and  the  small  bubble  footplece was  more
               expensive  to operate,  the large bubble air lift fcotplece with a 1 In air
               delivery line was chosen for  use during the rest of the In-well aeration
               testing.                       .                                 :      •
                    Sparging air Into the well decreased the efficiency of the air lift
               pump.  This was  consistent with air lift pump  operating  theory.  There
               was very little difference  In operating pressure  and cost to compress air
               between the large bubble and  small bubble sparger footplece.   The cost to
               compress air for  the  air lift pump and sparger combination  ranged from ^  .
               to 1U$ per 1,000 gal  for air-to-water ratios of  2:1 to 9:1.   These costs
               were similar to the air  lift  pump without the  sparger at the same air-to-
               water ratios.                                    .                        ;
                    There was no observable  difference In VOC removal between the large
               and small   bubble  sparger.  The  large bubble  sparger was  chosen for use
               throughout the rest of the  In-well aeration testing.
                    It was foundvthat  adding  air to  the well through the sparger could
               turn the entire well   into  an air lift pump and  cause water to be lifted
               up  and  out  of  the  well  borehole  and  onto  the punphouse  floor.   The
               air-to-water ratios were limited when sparging to the  point at which the
               most air could be added  without blowing water  out of the well  borehole.
                    In the footplece testing,  VOC removals were  similar for similar air-
               to-water ratios,  regardless of whether air was Introduced by the air lift
               pump  alone or by the  air'  lift pump and  sparger  combination.   Vinyl
               chloride,  with the highest Henry's Law  constant,  was the exception to
               this.  It  was better  removed  by the  air lift pump and sparger  combination
               than the air lift pump alone.
                                                   60
tj-^'i^ii


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             V."  :./             SECTION 8 . "  '

             ":-: '- AIR LIFT PUMP TESTING WITHOUT SPARGING
AIR LIFT. PUMP TESTS WITHOUT SPARGING - PROCEDURES            .   .     .

  1 •••. The air  lift  pump was tested without  the  sparger (In-well  diffused
aerator) at each of the three depths chosen  for  study.   The depths (130
ft, 200 ft, and 280 ft) were chosen based on water and VOC zones of entry
as determined during the wel1  characterization  stage of this study.  The
130  ft and  280 ft tests  were run  In duplicate.   The  air lift  pump
testing, without  a sparger,  Is represented  In the  first colum  of the
experimental matrix In Figure 12.  The  large bubble footplece and  1 In
air line were used as  a result of preliminary testing (see Section 7 for
details).  One of  the  tests at 130 ft was  performed with the 3A In air
line.
     As with  the  preliminary  footplece  experiments,  each air  lift pump
test  consisted  of  a  series  of 15 minute  runs  using various air  flow
rates.  The air flow  rates  ranged  from the maximum air delivery  rate
possible to the lowest  air delivery rate  which  would pump  water.   The
maximum air delivery was obtained by attaching both the air lift pump and
sparger air lines  (side  A  and  B of  the  air  delivery system shown In
Figure 10) to the air lift pump.  The lowest air flow rates were measured
by the small  air  rotometer (0 to 6 cfpm  Instead  of  0 to 60 cfpm), which
was placed on the A side of the air delivery system for this purpose.
     The actual procedure followed for each run within the air lift pump
tests  was  the  same as  that  used  during  the  air  lift  purp  footplece
testing.   At  the  beginning of  a testing  day,  the  static  water level
(water  level  before any  pumping occurred) was obtained.  The air lift
pump  was  turned  on at  the  maximum air  delivery rate.   The pump was
allowed to  operate until  the weir box was  full.   When the weir  box was
full, the  timer was started  to  measure  the first 15  minute  run.   After
five  minutes,  readings  were  taker,  of  all  the  valves,  gauges,  and
thermometers, as well  as the water flow rate and pumping water level In
the well.   Any necessary  adjustments to  rotcmeters or  pressure  valves
were  made  at the  five  minute  reading.   It  was  very  rare  that  the
rotcmeters or pressure reducing  valves  required adjustment during a run.
'At the  end of the  15 minute run time the  readings were  taken  again and
VOC samples were collected from  the raw water sample tap and the v-notch
of the weir box.   Once  all  of the readings and  samples were obtained the
hext air flow rate was selected at the  rotometer and the  15 minute run
clock, was  started  again.   This procedure was repeated  until  all  desired
;alr Flow rates had been tested.  Note that when  using  the air  lift punp
without a  sparger  It  was possible to move directly from one run to the
                                    61

-------
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'•'•'.•'•'.'-.: •••ซ-; Y ••'  . •  -•'•'- ••'•:•-'  C''.••ซ.ป•-• .'•''--;. .'•- .- '--"-   ' ' .'."--. '.'-'.•.-•".':'."•  V-'..-  .'•'•'  .   '•'..-•- •'"'••'.'•• •••':.'-' ^v^..^ Fa
. '-•;•• •-.. •;..,•-::-•-.. -.'•.; "•-';•'•• :'•••''.'/•..':••'_'  ' •."..'•"• '•'•'"  Yv' <"'.     '. '   ':   .• •. - '-     '-,. ; '• ซ- >'--'.-KS

 next.  When a sparger was  used It was  necessary to  provide a US-minute
waiting time  between runs to allow the  well to clear of bubbles so that
 an air-free raw water sample could be  collected.                           "_ •

 AIR LIFT PUMP TESTS WITHOUT SPARGING - RESULTS AND DISCUSSION          .       .' ..  > .    ', fs

      Air 1 Iftpunp operational  results are show In Figure 2U.  The graphs           •   . 5;|
 show  air lift  punp  operating  pressur&,  submergence and  wire-to-water             ••'•_-'K|
 efficiency for  tests run  at  each of the  three  selected depths  In  the            .'--•ฃ$
      The  submergence  of  the  air  lift  pump  determines  the  required             '
 operating  pressure.   If  the  air  lift  punp  submergence  Is too low,
 operating  air  pressure will  be  low,  but there will  be greater loss
 because of  air slippage so  larger volunes  of air will  be required.   If         -        ,
 the submergence Is very large, air slippage losses and the volume of air
 required will be  smaller,  but operating pressure  will  be very high.  Air           ;     '|
 slippage,  losses  and  high  operating  pressures  cause  loss   In  pumping            •
 efficiency.                                                    .                           hf
      At well  L-8,  the  greatest air lift punp  efficiency was predicted  to
 occur  at  65%  submergence.    Figure  2U   shows  that  did  occur.   The
 submergence obtained at the  130 ft depth  setting  was the closest to 65%,
 and the wire-to-water  efficiency was  the  highest  at  this depth setting.
 The   wire-to-water   efficiency   decreased  with   Increasing   percent
 submergence which agrees  with  the  literature  (5,29).   Figure 25  is a
 theoretical  punping  efficiency  curve adapted  from  Ivens   (29).   The
 submergence obtained for the three air lift punp  testing depths at well
 L-8  have  been  plotted  as  points  on  this curve.  The data  from this
 testing closely matches the  theoretical  curve,  showing  that  the  130  ft
 depth provided  the most efficient air lift pump.  Operation  of the air
 lift  punp at 280  ft (far  below the  point of  optimum  submergence) was
 difficult.  Debris and  oily  sludge-like material  were pumped up from the
 bottom of the wel1.                                                                       I '
      Figure 2k  shows the results of  duplicate testing  at the  130 ft and               • i\
 280 ft depths.  The squares,  plus signs and diamonds show the results  of                |.?:
 the air  lift punp with a 3A In air delivery  line.   All of the other          .      ;1
 tests were performed with a  1  In air  delivery 'ine.  The  smaller air line                :x-
 caused  a  noticeably  higher  operating pressure  at  130 ft, but this                *3
 difference was  not apparent  at 280 ft.  This  figure also shows that even                ;j
 with  a  different  size air  line, reproducIb111ty of  the air lift punp                I••-
 operational parameters was very good.                                             .        '•]'
      The  cost to  compress air for the air lift  punp tests  Is shown  In     .           \...
 Figure 26.  The alr-to^-water  ratios  tested ranged  from 1.3  through 10.6                j^
 to 1.  As expected, the maximum costs were seen  at  the highest air-to-                 i
 water ratios, where operating pressures were  highest.   With  the air lift
 punp at 280 ft, the maximum cost  to compress air was 28.U$  per thousand                jX
 gallons.   With  the punp at  200 ft the maxlmun  cost as  25ฃ  per thousand                |.:^
 gallons and at  130 ft  the maximum cost was 20.UC  per thousand gallons.                |;
 In comparison,  It  was estimated  that  the total  cost for packed tower                f^
 aeration would  be  similar to these  In-well aeration costs, but the  packed
 tower costs included amortization of capital, operation, maintenance and
 repumplng to  the distribution  system (33).  Since packed tower aeration
 also  achieves  better  VOC  removal than  air  lift  punping,  these tests


    .                                 62                               .
                                                                                  ,,.-:.

-------
                      11O
 fr
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 en
 to
 CO
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                       7O -
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      110
      100 -
                       TO -
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                             130 FEET
                            200 FEET
                               -  . SUBMERGENCE
                             -0-0-"	^PRESSURE
                                            EFFICIENCY
                                   SUBMERGENCE
              280 FEET
                                          EFFICIENCY
                         B* OPERATING
                            PRESSURE,
                            PSIG
                               i        eo        ao
                                ROTOMBTTER BSTTIHO
                               ' SUป!ERGฃNCE,
                                PERCENT
                                                                           100
                                                                                     120
                                         *•ป PUMPING
                                            EFFICIENCY,
                                            PERCENT
Figure 24.   Submergence,  operating pressure and pumping
            efficiency for air  lift pump  tests at 3 depths
            in well L-8.
                                                   63
                                                                                      ^
                                                                                               '::-3 :^m
                                                                                                       .*• - •*)
                                                                                                       -••
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                                                                                       ,;,i
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                    50
                    40-
                    30-
              Ul

              0
              L
              L
              y

              K
20-
                    10-
^^

 20
                                             280 FT
                                           ADAPTED FROW IVENS"(29)
                                              I    i     i    T    i    i     i    r
                                        40       60       80


                                              % SUBMERGENCE
100      120
                                                                                                  |
                                                                                                  I
                                                                                                 -:S
                                                                              1
                        Figure 25.  Theoretical air lift pump efficiency curve with

                                   points  showing a comparison to NFWA test data.
                                             .  64
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^ = AIR UFT PUMP AT 280 F * +

i
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+ 'ซ AIR UFT PUMP AT 200 FT

D = AIR UFT PUMP AT 130 FT _ D
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AIR TO WATER RATIO
                                                                         8
10
                              Figure  26..  Cost to compress air for air lift pump testing
                                           at three depths in well L-8.              --,  -.
\
                                                      65

-------
 v •-•.;
•Vv;
 A;  -J
        J*::."':'".-" ':•"•-'-'•'*'' •'•  '•./'-•:-'-_-;-.':--'--:: .-•-.•••.-••   '••-•.--.•..-;.."• .    •-.••••••'••ป:-/:'•'  -•:•-....••    : ;j;---^',^v'^;•'";'
        t     _  ' V  showed that packed tower aeration would be the  preferred aeration process   .  :    i '_-.'•
        !"•'•'.  •-•-'•'-';.-..'for VbC treatment over air lift pumping.                 V   .   \.~. • '•'."';:->  "r  ;     -  V \K^
        r   '• v ;"•• ."'••'••••."  The VOC removal  results  for air lift pumping without  a sparger are              pi
        '•.          shown In Table 10 and Figure  27.  Three VOCs were graphed to evaluate the      •     '__•'.. |.,f
        ':      -   removal capabilities  of the  air lift pump.   These  compounds were  TCE,           "  : I'd
        >.      ..   c-l,2-DCE and VC.  The air lift pump foptplece  testing Indicated that the
        :.       .;   VOCs found In well L-8 were removed  in an order which could be predicted
                ;J   by Henry's Law  constants.  Rather than  evaluate each compound  found  In          .
        '      "  "   the well,  these  three compounds were  chosen because they  represent the             ' [.|
        ;'..       .   major contaminant -(TCE)  as well as  vinyl  chloride (highest  Henry's Law
            ;  : --constant) and c-l,2-DCE (lowest Henry's Law constant).
        |       .    :      The results of  air lift pump testing have been analyzed similarly
                    to the  results  of the  air lift pump  and sparger preliminary footplece
        :..'•_     -   testing.   VOC  removal   percentages  could  be  expected  to  vary  from
              "      test to  test by at  least as much  as  the air-to-water ratio.   If  some
               -     other  factor were affecting  VOC removal, the  VOC  removal  percentages          -
               ...   would vary more than the variation of  the air-to-water ratios.  Table 10
                 '   shows the  variation,  %RSD, of  the  air-to-water  ratios and VOC removal
                    percentages  for  each compound  studied  In well  L-8.   The %RSDs  for the
           ,'.-.       air-to-water ratios  are,   In  most  cases,  lower than the  %RSDs for VOC
 ; •      :    .  • .    removal percentages.  This would Indicate that some factor,  other  than          •
 ' '                  the  variation In air-to-water  ratios,  was causing the  variation  in VOC
 1 •                  removal percentages.  Since the air  lift purp was operated at different
 , ^                 depths for these tests,  depth of the pump In  the well  was  one  possible
 k\ x,               cause of the VOC removal variations.
                         Figure 27 shows the  removal  curves for TCE, c-l,2-DCE,  and VC.  In
  Vi .       .'.       each case, It was difficult  to visually distinguish a  difference  In VOC
  "t\          :       removal at the various depths.   It might have  been expected that the 280
   ''•• •                ft depth would have provided  the best  removal,  because  the  air and water
                    contact  time was  the  longest.  Since  no VOC removal  advantage  was
                    obtained by  operating  the air lift  pump  at  greater  depths,  and  the
                    greater depths were  more expensive  In terms of  operation,  an  air  lift
                    pump  treatment  system  should  be designed  to  operate at  the  maximum
  "•	   .            pumping efficiency depth setting.
                         Raw water  concentrations  for  the  three  VOCs  discussed above  are
            • i,       shown  In  Figure  28.   Because  of  the  nature  of Henry's Lav/,  it  Is
    _._       '        generally accepted that In aeration,  removal  efficiency  Is not related to
                    raw  water  concentration.    This  figure  shows  that  the   raw water
                    concentration varied widely from one  test to the next.  Notice also,  that
    .                the raw water concentrations  change  a great deal from run to run within a
   I                single test.   This Is why a raw water  sample was taken for every treated
   I   .             water sample.
            "            The raw water  variation from test to  test may also  Indicate  that              ||
  —    .    .        other conditions within  the  well were  changing.  If the  concentrations                1
  /                 varied, perhaps the zones of VOC entry  Into  the well  also changed.  This               -\
            n       could be a factor, other than depth of the air  lift  punrp, which afvected                f
                    VOC removal.   This possible effect of well conditions changing with  time              ||.
                    will  be discussed further when sparger results  are shown.                              j;j|
                         Variation in the analytical method for VOCs was 10% or less.  Some              H
                   :of the %RSDs for VOC  removal  were less than 10% which could  be  from the              y
                    analytical   method.   At   several   air-to-water  ratios,   however,   the              i;i
   /                variation was greater than 10% which could not  be explained by variation              t'/j


   i     •                                               66
                                                                                                             3
                                                                                                             :j

i •  .    .;   •          •   .                    ,                        .    -.                 •        •  •  I
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-------
                  \
                                                                                                                                              ....: \:.'..
p. /
                              TABLE-10V  VOC  REMOVAL BY AIR LIFT PUMP WITHOUT SPARGING (AVERAGE OF ALL THREE PUMP DEPTHS)  /j:. :  ,;''i.
AIR  TO WATER
RATIO	


AVE    %RSD   N


1.3    .3.5   3


1.7


2.5


2.9


3.5


5.3
                                       -   1


                                      6.1  2


                                       -   1


                                      2.7  3


                                       -   1
                              9.4
1
                              10.6    5.66
                                                   %  REMOVAL  OF VOCs

                                                                                                     ttSi"
TCE


AVE    %RSD


27.7   21.1


41.9


33.7
                                                                   PCE
c-l>2-DCE     1,1,1-TCA   '  1,1-DCE
                                                                                vc
                       AVE   %RSD   AVE   %RSD   AVE    %RSD    AVE  %RSD  AVE   %RSD


                       35.3  8.76   18.1  26.8  . 41.4   21.6    55.0 15.3  43.8  11.5.


                       41.8    -     24.5    -     44.6     -     52.6    -     -     -


                       35.6    -     18.6-49.2     -     54.7    -   52.1   .-   :


                       56.5    -     34.9   . -   .  60.9     -   .72.8    -   60.0    -:
                                                                                                                                                 -•^
                                                                                                                                                 ..'-'•:.•:."•!
50.0


46.2    9.20    60.5   6.06    33.3.    4.68  59.9   4.09  71.9  ' 3.69  73.2   .4.


48.8     -   •   59.4    -     .30.7 '    -    70.3    -.    '72.9   \- ;,  74.8  ;  J-


59.5  ;•-      75.2    -      46.4     -    75.3    -   '  84.6    -  100.      -


64.7    7.15  ;  76.7   3.04    47.4   11.8 i'.1 81.8 :} 3.57;  83.8   8,90  90.4'.':/.7.
                                                                                                   '•; •.   ••''••" • :'•>•'•'  " .'.'  '••" ''-.•' '.'• '.'•-.?...'.• •/'••'? *'-':'', <'.'i
                                                                                                    '••••-  .'-  V" ••'-•;.•••  •'•  I..-.'•'.* ;-• ''  •• '••' ' ••'. "•;•'' :V;' •". ••* ป'.'. '-l^f



                                                                                                   '  •':•"•.- •''  '"•• '"•"••!-''''^,''-  ' '::-l '•'•"•''':. :.^'^'-"k^A-^->V;^
                                                                                                   ffซaJปry^t<^^ai"""^lซr|i^'i.i'''*'ili'i''rv'^;'i^-*<''J^*fyi''.' '-Tfrf*^^1'*"*?VT'i*i*r"f''""'*rrrwftป!r'rrfrT?i:*^T-'i*taT^51

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                                                                                     r™.*? T*-1—,~7'T*!C'"7'ir%1'"ซ"?	> _T*-*ฃlTr-K"aTrr -
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ao -
io-
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                              ปo -
                              70 -
                              BO-
                              ao
                              10
                              100
                              BO
                              TO -
                              •o -
                              BO -
                              40 -
                              ao -
                              ao -
                              10 -
                                o
                                           TMtOHUOftOC1>nUCNB RBMOVAU
             •—1 .a—DIOHUDROGCTHYUCNEC REMOVAL.
           =-Pump @ 130 feet
           = Pump @ 130 feet  (Dup Test)
           = Pump @ 200 feet      .
           = Pump @ 230 feet
           = Pump @ 280 feet  (Dup Test)
                                           VINYL. CHLORIDE REMOVAL.
                                                                                            10
                                                                                    "Si
                                                                                                                   n
                                                         AIR TO WATER RATIO
                                    Figure 27.   Percent renoval of major contaminants by the
                                                 air lift pump at  three different depth  settings
                                                 in well L-8.
                                                            68
                                                                                                                   V -'•!
                                                                                                                   Pi
                                                                                                                     -'1  -

-------
 1.* •
 1.1
 . 1
 o.e
O.T
OJt
o.a
0.1
aoo

100
 so
 10 -
                                        280 Feet
                                                200 Feet
                                                    130 Feet

                                                130 FeetTTxro)
            TOE IN MAW WATOR
           280 Fej* (Dup)
            0—1.2—DOE iN |4A*T WAFER
            VO IN RAW WATER
                                          130 Feet
       130 Feet (Dup)


                  • ^
                                                       10
                           AIR TO WAPER rtAHO

       Figure 28.  Well L-8 raw.water VOC concentration during
                   air lift pump testing at three de^chs.
                              69

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 during analysis.

 AIR LIFT PUMP TESTING AT GLEN COVE, NY

      Air lift purpjng was  also evaluated for VOC  control  at Glen Cove,
 New York  In  another U.S.  EPA funded project  (34).   The  air  lift punp
 evaluation was only a minor portion of that project; adjacent wells were
 used for evaluation of other control  technologies.                  ., x
      In  the  Glen  Cove  project,  a  shallow  well  was  selected  for
 Installation  of  an.  air  lift  pump..  The  design  was   based  on  70%
 submergence and water delivery of 50 gpm.   The footplece configuration
 was an open-ended  pipe;  the air  line was located concentrically within
 the  eductor.   Air  and water  flow rates  were  measured  by  similar
 procedures to those employed at NPWA.  A  blower was used rather than an
 air compressor.
      There were  several  factors, however,  that  Interfered  with proper
.evaluation of air  lift  pumping.   Although designed for 70%  submergence,
 those  conditions were   rarely  realized.    Seventy  percent  assumed  no
 drawdown resulting from  operation of nearby  wells, however nearby wells
 were In frequent operation.  Pumping water level was measured only once.
 It  revealed  58%  submergence  as  a  result of   adjacent  well operation.
 Although designed  for an  air-to-water  ratio near 3.3 to give optimum
 efficiency, It was operated at ratios of 11 or greater.  Finally, optimum
 design conditions suggest an eductor size of 2  to 3 In Inside diameter.
 Allowing for  the concentric air  line,  the 4  In eductor  that  was used
 resulted In  an  equivalent   Inside diameter  of  approximately 3.8  In.   A
 larger  diameter  In cotrbinatlon  with  larger  air  flow  would  promote
 slippage.   Slippage and reduced  submergence  would  promote  decreased
 efficiency.  The operating  conditions for the one day when pumping water
 level  was measured,  are  given In  Table.11.

        TABLE  11.   GLEN COVE AIR LIFT  PUMP  OPERATING CONDITIONS (34)	
 Water flow,  gpn                      LT or = 44
 Alr-to-Water Ratio                   GT or = 11
 Lift, ft                                    12.7
 Submergence,  ft                             17.75
 Percent submergence                         58
 Wtre-to-Water Efficiency (a)                   3.7
 Eductor diameter,  inch (b)                     3.8
 Cost to Compress Air $/1000 gal  (c)            4.2
 Date: g i ven In:
   a  Assuming air .compressor of type utilized by NPWA
   b  4-lnch 1.0.  less nominal  1-Inch concentric air  line
   c  Assuming 6^/kw-hr

 LT:  Less Than
 GT:  Greater Than
                                     70

-------
:-:,;,- The very low efficiency at higher than optimum alr-to-water ratio Is               ง
;consistent--with NPWA  air lift performance.   The relatively low  cost to        .     . 1;
.compress  air  at  that air-to-water  ratio  results  from  operating  In  a        •;.':>    |
 shal.low well; the  compression ratio at Glen  Cove was small  relative to               |
 compressing air under 130 ft or more head at NPWA.                   '     !        <'  . -|;
     .TCE, PCE, c-l,2-DCE and  1,1,1-TCA were measured  In  the well  outside          .     ^
 the eductor and  effluent from the weir box/separator.   Results  for the               f!
 principal VOCs are given In Table 12.  The data are consistent with those               j!
 developed at•NPWA • In  that air 1 Ift  pumping never achieved removals that              '\
 would make the technology comparable to packed tower aeration.   .  '   . -    -  .  '  ••'"•     i;
 -.'••--•.-  ''. -' •. -    -. -:  -'     •        '  -  .•    '  "  '      •••.•- -.' ' "    '    '•'  •'""•" '   :•• :;- -'I
      TABLE 12.  VOC REMOVAL BY AIR LIFF PUMPU-JG AT GLEN COVE (34)               VY     I
NUMBER
TESTS
2
13 :
8
6
' AIR TO
WATER RATIO
11
15-20
21-27
34-51
RANGE PERCENT REMOVAL WATE* FLOW CONTACT
TCE
58 ฑ 2
54 ฑ 10
54 * 3
52 . ฑ 3
c-l,2-DCE GPM a
38 ฑ 2 44
33 ฑ 14
27 ฑ 6
31 ฑ 13
TIME, SEC
24



 a  Data only reported for selected alr-to-water ratios

 CONCLUSIONS FOR AIR LIFT PUMP TESTING WITHOUT SPARGING

      The operating efficiency of the  air  lift  punp was greatest when the
 punp submergence was  near 65% Cat  the  130 ft depth  setting).   This was
 the submergence which the literature predicted would produce the greatest
 pumping  efficiency.   The air  lift  pump  efficiency decreased  as  the
 submergence increased, which was also described In the literature.
      VOC removals  for the air  lift pump without  a sparger  ranged from
 maxlmums of 90.4% for VC Cbest removed according to Henry's Law Constant)
 to  47.4% for  c-l,2-DCE  (lowest  Henry's  Law  Constant).   The best  TCE
 removal obtained was 65%.
      VOC removal was  poorer  et  the 280 ft  setting of the  air  lift pump
 than It was for the 130 ft or 200 ft settings,  which were similar to each
 other  in terms  of VOC  removal.   Pump  operation was  difficult at  the
 deepest setting.
      Raw water VOC concentrations varied widely from one test day to the
 next, as well  as varying within  a particular test.  This  confirmed the
 predictions  derived   from   the  pump   test  conducted  during   well
 characterization and emphasized  the need for frequent raw water sampling.
      The cost  to  compress  air  for  the  air  lift  pump  was found  to be
 similar to the  total  costs (air, operation and maintenance)  of a packed
 tower aeration  system.    It was  concluded  that  In-well  aeration by air
 lift pumping  alone would  not be ah  adequate  substitute technology for
 packed tower aeration.  Air lift purp testing performed at Glen. Cove, NY,
 under a separate U.S.  EPA funded project,  confirmed this observation.
                                     71

-------
;                                                 SECTION 9

                                    AIR LIFT PUMP TESTING WITH A SPARGER


                 AIR LIFT PUMP TESTS WITH SPARGING  - PROCEDURES

 -:••••              -   The  air  lift . ptnp   was   tested  with  the  sparger   In   various
   •••••      ;       combinations of depths, as shown by the experimental matrix In Figure 12.
   ;  '  .      .-...: The air lift pump was  the  same one  used  In air lift pump testing  without
   <-'•.'.          -  a sparger.  The sparger was made  of 10 ft sections  of 3/4 In plastic pipe,
   1    .   .       connected with fittings to  reach the desired  depth.  The sparger  did not
   ;.'.     .        have any type  of  attachment at  the  footplece,  as was determined  In the
   ;              Preliminary Footplece  Testing (Section 7).
          •"-.'        The testing procedure  established during the preliminary footplece
;                 testing and air lift puip  testing was used  for all of the air lift pump
-                 and sparger combination  testing.   The static  water  level was recorded,
                 then the air lift  pump was operated at a constant  air delivery rate of 20
                 cfpm.  This  rate  was  chosen because it produced  an  efficient air  lift
                 pump In terms  of  punplng Cover,  though  it was not the most efficient  In
                 terms of VOC removal).  The weir  box was allowed  to fill, so that water
                 flow rate measurements could begin.   Next,  the sparger was turned on to
 :.';-              the first selected  flow  rate.   The tasts were conducted as a series  of
  .               fifteen minute runs.   For  these tests, the A side of the control  board
                 was used for the air lift  punp,  and the B  side of the control board was
                 used for the sparger.   (See Figure  10 for  a diagram of  the  air  control
       .   .       board).  After each run using a sparger, air delivery  to the  sparger was
       .          stopped,  and  the  well was  allowed  to clear  of  air.   During  the  well
    "             clearing time,  the raw water  tap  was sampled   and  monitored  for  DO
   :.'..'           concentration.   When   the  DO value  reached  what It  had  been  before
       '      •   sparging was  started,  a  raw water  sample  was collected,  and  the  next
                 sparger flow  rate  was started   to begin  the  next  15  minute  run.   An
                 average time to clear  the well of air between  runs was  45 minutes.  This
                 clearing was an Important procedural difference between  running tests of
                 the air lift  pump with the  sparger as opposed to without the sparger.
                 When a sparger was not used, the only  air being Introduced  Into the well
                 was being  Injected directly Into the air lift purp, and therefore  the air
   i  '            would not affect the Integrity of a  raw water sample.   While  the  sparger
                 v/as operating the  raw  water sample punp was surrounded  by aerated water.
                 Collecting  the raw water while sparging would  result In  a sample  full  of
; i               bubbles,  which  Is unacceptable  forr~VOA sampling.  It  was Important  to
                 collect raw water  VOC  samples for each run,  because preliminary tests "had
/ '   '           shown that  raw water VOC concentrations  varied a  great  deal,  especially
               •  When the well was  first turned on.   The air  lift pump could  not be turned
   -'...'.        bn and left on for the nunnber of days that  it might take to allow  VOC


   -•''.'•..:..''':      ..".-•            .72            '

-------
                                                  A
                                                   \    ~~
          doncentratIonsto level off (see pumping test results, Figure 9), because        '  .
          the portable air compressor which we used was too loud to leave operating            '
          overnight In a residential area.           .                        .       '.     •
             ,=  The  operation  of  the  sparger caused  problems  with  the  method
         "originally chosen to measure  the water  level.   A 1/2 In plastic pipe had            :
          been  lowered  Into the  well  where an  electrical resistance water level
          probe was  used to measure  the water  level  In the  plastic  pipe.    This
          design worked  well  as long as  the  sparger was not  operating.   When the
          sparger was operating In some  configurations,  the air from the sparger
          entered the plastic  pipe for the water level  probe and  actually  turned
          the  probe  pipe  Into  an air  lift  pump  eductor.    This  water  level
          measurement problem made  it  Impossible  to determine  air  lift  pumping
          efficiency  while  the  sparger was  operating   and  several  tests  were
          repeated  In  order to  obtain pumping efficiency  data.   The water level
          measurement procedure had to  be changed to an  air pressure method, which        -    . •
          Is described In full In Section 6, Experimental Design.
               Air  lift  pump  operational  problems  occurred  at the  280  ft  depth
          setting, so these tests were not  repeated.  Operating the  air lift pump
          this close to  the bottom of the well caused an  oily sludge to be  pumped
          out  at  the  beginning  of each  testing cycle.   Water  flow  rates  were
          Inconsistent.  No pumping efficiency data was obtained at this depth.

          AIR LIFT PUMP TESTING WITH SPARGING - RESULTS AND DISCUSSION

               Figure 29  shows the wire-to-water  efficiency  of the air  lift pump
          with and without sparging.  It  Is Important, when looking at this figure,
          to realize that the  curves  for air  lift pump efficiency with and without
          a sparger are shaped for fundamentally different reasons.  The curves for
          the  air  lift  pump without  a sparger were created  by adding  Increasing
          amounts of air directly to  the air  lift pump  footplece,  thus  Increasing
          the  air-to-water  ratio for  In-well  aeration.   As discussed earlier,  an
          air  lift  pump  has a  point  of maximum  efficiency,  at which the minimum
          amount  of slippage  will  occur  In  the  eductor  pipe.   Operation  with
          air-to-water ratios greater than the maximum efficiency will cause  a drop
          In the efficiency curve.
               The  curves  showing  the  effect of  the sparger  on  air  lift  pump
          efficiency were obtained by operating the air lift pump at a constant air               L
          delivery  rate   (20   cfpm)  while  increasing  air  to the  sparger.   The               f;
          efficiency of  the air lift  pump  was  observed  to  have  dropped as  the               I
          sparger  air delivery   rate  was  Increased  (which   Increased  the  total               I-
          air-to-water  ratio  of  the  In-well aeration  system).   This  drop  In               j*
          efficiency  of  the   pump was  caused  by  decreasing the  water density               \
          differential across  the  pump  footplece,  which  provided  the driving force     .          };
          for operation  of the pump.   Even though the wire-to-water  efficiency of     ',          [;
          the pump decreased while sparging, It still remained higher than when the               \
          air  lift  pump  was operated  at Increasing air  delivery  rates, without  a               f.
          sparger (as examined In terms of total  air-to-water ratio).                             |-
               Figure 30 shows amounts of water pumped with  and without sparging,               fc
          with the air lift pump set  at 130 ft and  200  ft,  respectively.  The air               fc
          lift pump without a sparger pumped more water than the air lift pump with               [ป
          a sparger at a given total air-to-water ratio.                                           I,
               Even  though  less  water  was punped  when  the  air  lift  pump  was              T


                                               73
;

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n NO SPARGER 8-10-83 = a
D
n SPARGER AT 130 FT 4-3-84 = +
. , . SPARGER AT 200 FT 4-3-84 = ซ
.n + ; -.'.. -.SPARGER AT 200 FT 3-18-85 = A
• % ' •;-' : " SPARGER AT 280 FT 3-19-85 = x
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AIR TO WATER RATIO


Figure 29. Air lift pump efficiency curves showing the
effect of operating the air lift pump while
sparging.

74
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PUMP AT 130 FT
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D • -, .' .•••-.
SPARGER AT 130 FT
;. SPARGER AT 200 FT
• ; . ' •'.*•.
a SPARGER AT 200 FT
' - SPARGER AT 200 FT
o -....'

iff*1 ฐ ฐ a AIR UFT
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AIR TO WATER RATIO
4-3-84 = +
4-3-84 =. '*

3-18-85 = A
3-19-85 = x

PUMP AT 200 FT






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;••'•' Figure 30, Rate of water punped by the air lift pump with .'.''• :.




•X
! X
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i . • . :\ •
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,





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and without a sparger.
- 75







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. . - , . '. ' " . '..-->*
" • • . 
-------
- — \ '

                operated with  a sparger, the air  lift  putp efficiency was greater with
                the sparger than without.  This was because,  for  any  air-to-water ratio,
                only a portion of the total air being delivered was used  by the air  lift
                pump to move water,  so only a portion of the total air delivered was used
                In  the  air  lift  pump  efficiency  calculations.    In terms  of  pumping
                efficiency, for a given  amount of  air to be delivered, It was  better  to
                use the  air lift  pump and sparger  combination than  the air  lift pump
                alone.
                     Even  though  less  water was pimped  for the same  air-to-water ratio
                while air  lifting and sparging,  as  opposed to air  lift pumping alone, the
                cost to compress air for the combined operation was less than  for putting
                all of the air Into the air lift pimp.   See Figure  31 for the  costs  to
                compress air for the various air lift pump and sparger configurations and
                compare  this with Figure 26 which showed  the costs  of air lift pumping
                without a  sparger.  At the same air-to-water ratios It was less expensive
                to operate the  air  lift  pimp-sparger  combination  than the air  lift pimp
                alone; however, the combination system allowed a  larger amount  of air  to
                be delIvered.  At these  high air delivery rates,  the  costs exceeded 3(K
                per 1,000  gal.  Since this was only the  cost to compress  air,  that makes
                this method  cost  more than a  packed tower  aeration  system (34), which
                achieves better VOC removal.
                     Table 13 shows the results for testing the sparger with the air  lift
                pimp at  130 ft.  The % removals shown are averages for all three sparger
                depths combined (130 ft,  200 ft, and  280 ft).  These  removals  are shown
                next to their respective air-to-water ratios.

                          TABLE 13.   VOC REMOVAL WITH AIR LIFT PUMP AT 130 FT
                                     (AVERAGE OF ALL 3 SPARGER DEPTHS)

AIR
AVE
2.2
3.C
3.2
4.2
5.7
7.3
8.6
12.
TO WATER
%RSD
9.4
1.7
0
6.3
3.3
3.8
1.2
4.8
N
5
2
2
4
5
it
2
5
TCE
% REMOVAL
AVE
33.0
42.6
39.6
49.3
55.1
61.4
66.4
78.3
%RSD
19.6
8.45
9.71
5.83
11.0
18.2
1.05
7.98
c-l,2-DCE
% REMOVAL
AVE
24.6
28.7
29.2
34.6
39.8
45.2
53.0
65.0
%RSD
11.1
0.35
19.2
2.70
14.8
21.6
2.26
13.1
VINYL CHLORIDE
% REMOVAL
AVE
62.3
79.0
77.8
91.2
96.0
97.6
97.5
98.6
%RSD
9.93
0.38
10.0
4.87
2.97
0.79
0.82
0.40

                As with the previous testing,  air-to-water ratio varies,  even at  the same
                                                    76

-------

 40

'so.

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 an

 90

 1O

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.'.-. •'

 4O •

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 so

 aa

 ao

 IB

 10

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 ao -
 ao -
 IB -
 10 -
                 AW UPT PUMP AT 13O PT
BPAROOt AT aSO PT
6PAROSR AT 2OO PT
8PAMOCR AT ISO PT
                  AIR UPT PUMP AT 2OO PT
                        AIM UFT PUMP AT 28O PT
    o      a
                               ซ     10    12     1-*     10     ia
                          AIM TO WATEK RATIO
       Figure 31.   Cost to compress air for air .lift pump and
         .  • .    .   sparger testing at well L-8.
                            77

-------

I ;^\r ;-;   rotometer.  setting,  because  of  changes  In  pump efficiency  caused  by      _;.".;
i/r'.V 'varying well water  level;  The air-to-water ratio variation and  the VOC        . ".'; '.'.-.;
|   -, ..      removal variations are shown as  % RSD.   If nothing but the air to water  .
i v  . :.;  V    ratio was changing, the  %RSDs  for the VOC removals should be  similar to
T.      ,     the %RSDs for the air-to-water ratios.  In Table 13 the %RSDs  for the VOC
p.       ;•   .removals are greater  for the removal of  TCE  and c-l,2-DCE than  are the
; ,    .!      %RSDs  .for  the  air-to-water  ratio.   This  Indicates  that   for  these           '": :'H
i       .'.-.',' compounds,  there was some other cause of  variation besides the variation               3
i   -   .      In atr-to-water  ratio.   Since these results are compiled from testing               ||
J.  -.-'..   '•-.---  with the sparger at three different depths, .the sparger depths might have               ||
 :'••" :         been assumed to be the  cause  of the variation.   An examination  of VOC               ji
 , :      :     removal data Csee Figure  32)  shows there was no  pattern  associated with               ^j
 ;-•':"'       depth  of the  sparger.    The  variation  appeared  to  be.  caused by  poor        .       R
 ,'-.-•.      duplicate testing whan there was  long period  of  time  between  tests.  The          .  .   Pt
 •; .  " . ,.     footplece testing  had shown very good  reproduclbll Ity  of repeat tests               fj
 ;/'           when they were  run  within a few days of  each other.   All air and water
             flow rate measurement equipment was  checked  for  proper  calibration and               3
        . t    the VOC analytical quality control data was evaluated, yet no  changes had
 ;  "   .. :'    occurred  In any  of  these over time.   It  was  known   that  raw water
             concentration  and well  water  levels  were,  changing.   These could  be
 -            Indications that  VOC  or water  zones of  entry  might  also have changed.
 ;        .    While  It  Is generally accepted  that VOC  removal  Is  Independent  of raw         .
          :   water  concentration,  water   entry  zone changes  might  affect  the
             reproduclbllIty of In-v/ell aeration over time.
                  Figure 32  Illustrates that  the vinyl chloride data  did not show as
             large a variation as the TCE or c-l,2-DCE.  Table 13  shows the %RSDs for
             vinyl  chloride  removal   to be  similar to or  less than  the  %R5Ds for
             air-to-water ratios.  This Indicated that nothing other than air-to-water
             ratio was  causing variation  IT  VC  removal (unlike TCE  and  c-l,2-DCE).
             Vlr.yl  chloride  had the  Mghe5,t  Henry's  Law constant  of the compounds
 ;            tested and was  very  rapidly  removed to greater  than  90%.   The variation
             decreased as percent removal  Increased.
                  Tables 14  and  15 show the VOC  removal data for tests with the air
             lift pump  at  200 ft  and 280  ft respectively.   These  results  show the
             same variations In %RSDs as the  results for the  air lift  pump at 130 ft.
             The tests at 200  ft were conducted over  the  longest period of time and
             they show the greatest variation.  Figure 33 illustrates testing with the
 :            air lift pump  at 200 ft  and  Figure 34 shows the  280  ft air lift punp
             tests.   No  pattern  existed which would  suggest  a  difference  In VOC
             removals  caused  by  the  depth  of  the   sparger.    Instead,  changing
 '       .     geological  well conditions over time were  the most likely sources of the
             variation.                                                                   ''.'••
                  The maximum air-to-water ratios which  could  be achieved  varied from
             12:1 with the air lift punp at  130  ft,  to 17:1 with the  air  lift at 200
             ft; to 16:1 at  280  ft.   The  air-to-water ratio was limited by the point
             at-which water was lifted out of the well  bore hole by the foaming caused
             by the sparger.   This maximum air delivery point was Influenced mainly by
 :     ..••-.  the static water  level of  the  well.  When the water  level was closer to
             the surface, the water blew out of the borehole more quickly.
                lw

-------
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C-1.2-DCE RQ50VAL - . • ^ - ,Vf.'
:.:'. -V:.;-:'-; '/•;;0'':s;r;;Vv.::v-;-v:'-:^
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. 9 ." ,;..-•- . .
+ x SPARGER AT 130 FT 3/17/83 o
* SPARGER AT 130 FT 3/23/83 .*

. - SPARGER AT 200 FT 6/22/83 *
•'-•'• - '•-••" ' ;-' .
. SPARGER AT 200 FT 4/10-84 A

VC REMOVAL SPARGES AT 280 FT 8/3/83 x

N
fl
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' • 4
                                                                   RATIO
                                  Figure 32.  .VOC removal data for air lift pumping at 130
                                            .  feet while sparging at three depths.
                                                         79


-------
            i
            Pu
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ao-
ro -
ao-
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ao -
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•4O -
ao -
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10 -
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TCE REMOVAL
o B a K
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T x
X X
a

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x

C-1.2-DCE. REMOVAL ' •' .. , • , -. , •• .... .
''.'•' •;••.•,'"-•'*' " n: .•'-, • w :';'. '-T ' •',•' x :
- '.-''•/ - ' •':.':• * -n. ฐ T .*'V ' A ."'x '•' .. .'•.-' :
" ^ . . * •• • '
- ' D • • • -•••"'
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T a '•'''.-'..:.-.•'." ' •'.''
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v • . .-•''• "• -.. • ' -- : ;, -.; -: .' -' - _; ' - '
u B a *T * S *
•jj -xK x.
SPARGER AT 130 FT 8/19/83 n
A x SPARGER AT 130 FT 4/3/84 ซ.
B .. SPARGER AT 200 FT 8/12/83 * '
. SPARGER AT 200 FT 4/3/84 A
•••-.'•" SPARGER AT 200 FT 3/18/85 x
VC REMOVAL ... SPARGER AT 200 FT 3/19/85 *







. -„'











                                         a      a     10     12
                                           AIR-TO WATER RATIO
                                                                          ia
                                                                                 ia
                       Figure 33.  VCX3 removal data for air lift pumping at 200 feet
                                   while sparging at three depths.
                                                                                                   i"*
                                                                                                   1$
                                                                                                   If
                                                                                                   i •-?
                                                                                                 •  ;.'i
                                                                                                  ri
                                               80
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                                                                        'v   •*-
      TO-
      1O-
O


PU
      ao-

      10 -
      TO-
      ao-

      10-
           TCE REMOVAL
  a
B *
                            fi
           C-1.2-DCE REMOVAL
                            fi
                            ง
  SPARGER AT  130  FT 9/14/83


  SPARGER AT  200  FT 9/29/83

  SPARGER AT  200  FT. 12/1/83


  SPARGER AT  280  FT 10/6/83
           VC REMOVAL
                              o      •     10 .    ia
                                A1K TO-WATER RATIO
                                                                1*
          Figure  34.  VOC removal  data for air lift pumping at 285
          -  ,-..  ••''..'.''  feet while sparging at three depths.
                                                                                        r  i
                                                      i  i
                                                      K, "J
                                                      fcr1 ^

                                                      '- '">
                                                      I* "^
                                                      t '^
                                                      f  3
                                                      I _t


-------

    " -^ TABLE I/*.  VOC REMOVAL WITH AIR LIFT PUW AT 200 FT,
      '.'•' K^-y'^V  .(AVERAGE OF ALL 3 SPARGER DEPTHS)
• ':'••. .....< •'--•' ':•-•. ' , . •-.•-;. '- -.-•-".- '• ' • •.'.--••



; "AIR TO WATER
0 AVE
1.8
2.5
3.5
5.2
. 6.0
- 7.2
8.9
10. .
12.
15.
!7.
%RSD
7.9
-3.7>
6.2
6.3
V3.4
-2.3
7.7
1.2
1.9
0.69
1.2
N
' 3
:3
3
6
3
-3
5
3
3
2
2
TCE
. : % .REMOVAL
."• AVE %RSD
39.6 . 3.04
; .29.7 19.1
50.0 18.4
59.4 26.7
66.5 12.4
75.8 10.7
71.5 20.6
65.2 .20.3
72.5 15.4
77.8 4.57
84.2 2.67
c-l,2-DCE ,
• % REMOVAL •?.
.AVE %RSO .
24.7 7.49
26.9 17.5
37.0 23.6 ;
45.7 26.9
50.8 13.0
62.1 16.7
59.0 23.5
56.1 18.3 :
60.8 18.0
68.8 9.45
75.2 6.18
VINYL CHLORIDE
. % REMOVAL .•-.•• ':
AVE
58.7
66.0
86.6
93.1
92.8
98.0
94.1
94.7
95.5
96.0
98.6
%RSD
9.11 ,
5.58
8.28
6.01
5.48
0.87
4.43
3.59
3.07
2.24
1.37


-
TABLE

15.

: VOC REMOVAL WITH
(AVERAGE OF ALL
AIR LIFT PUMP AT
3 SPARGER DEPTHS)
280 FT





T,

AIR TO WATER
AVE
. 2.1
3.7
5.4
7.2
7.8
8.7
11.
16.
%RSD
8.4
1;3
3.3
2.0
0.0
6.4
3.3
—
N
4
3
4
.*:''
2
3
3
1
TCE
% REMOVAL
AVE %RSD
23.4 62.1
34.5 17.7
55.7 6.19
61.4 7..64
67.9 4.71
73.1 12.2
72.3 13.4
88.4
C-1,2-DCE
% RB1QVAL
AVE %RSD
13.4 70.3
23.7 36.9
41.6 13.2
51.5 8.82 r.
58.2 2.66
62.8 11.0
63.5 12.9
83.0
VINYL
CHLORIDE .
% REMOVAL
AVE
42.7
83.6
92.0
95.7
97.6
97.4
97.6
99.7
%RSD
59.1
6.00
6.75
1.95 •;.-.
0.36
0.90
1.87
_

CONCLUSIONS FOR AIR LIR PUMP TESTING WITH A SPARGER

     Operation of the sparger while  air lift  puiping caused the air lift
purp  effIcIency  to decrease.   This  was  predicted  by  air  lift  purp
operational theory,  because the density  difference across  the air lift
purp eductor  Cthe oorp's driving  force)  was reduced  by sparging.  Even
though the sparger  caused  the air lift pump  efficiency to decrease, the
pump efficiency with a sparger was higher than If all of the air had been
delivered  to the air  lift  pump alone;  therefore,  In  terms of  pump
efficiency (and  cost),   It  was better  to operate  an air  lift punp and
sparger combination than to operate an air lift ptnp alone.
     The  maximum VOC  removal  percentages for  the  air  lift  purp and
sparger combination were 98.6% for VC, ..65.0%  for c-l,2-DCE and 78.3% for
TCE.  The air lift  punp and sparger combination  was able  to produce a
higher alr-tb-water ratio (17:1)  than  the air  lift  pump alone  (I1:!).

       :• ..'  •':•-'    •••.  '            82         ,': '..  ''.. "     .-'  -•"' •-:  •   .'
                                                                                         'i;.S
                                            ,v
                                                                                             'r?- *-

-------

r.
t;
• -This  accounted for:the  higher VOC  removal  capabilities of  the "combined
;i system>  . When .sparging,  the alr-to-water  ratio was limited  to the point
. :"at which -adding more air caused water to foam out.of  the top of the well.
1-vhead.-;.In  a well-.v  .which, would   make  It   suitable  for  an  emergency  treatment
  technique.  The following experiments using an  electric submersible, pump
 .and   air  sparger  were   designed  with  the  goal  oF  Investigating  a
  short-term, emergency VOC treatment technology,                       -
                                              83
                                                                                                  '  !m

-------
                 ;•..   ,  .;.  •  SECTION 10
                  ELECTRIC PUMP TESTING WITH A SPARGER
ELECTRIC PUMP TESTING WITH SPARGER - PROCEDURES                    '"•''•   -

     For   this   portion  of   In-well   aeration  testing,  an   electric
submersible punp was  used In corb I nation with a  sparger.   Since the air
lift punp  testing with  a sparger did not  Indicate  that  In-well  aeration
would be an effective long-term treatment option for VOCs, this portion
of the study was designed with a short-term emergency treatment  method as
a goal.  In many cases, electric submersible pumps  are  already  In place
In drinking water wells.  The  sparger which was used for this experiment
was  of the  simple,  open-pipe,  large  bubble  design used   In  air-lift
pump/sparger combine ".Ion testing.  One Inch plastic pipe was used Instead
of 3A In,  to reduce air delivery costs caused by higher pressures In the
smaller pipe.   The electric pump was operated at one fixed depth (200 ft)
which was below the zones of significant water yield (see Section 5). The
sparger was tested at three depths (130 ft, 200 ft,  and  280 ft).  Figure
35  shows  the electric  submersible punp  and  sparger combinations used.
These were the  same  equipment depths examined In  the  air lift testing
portion of this  study.   The  depths  were chosen on the  basis of  well
characterizations discussed  In  Section  5.   Installing  and  moving  the
sparger was  a  very easy  task and  could be  performed  In  a matter  of
minutes, which  was  consistent with the  goal  of  developing an  emergency
treatment procedure.
     As with  the air  lift  pump  testing,  the electric  pump  experiments
were broken  Into tests which  consisted  of several  fifteen minute runs.
Each test  was  conducted with  a single  equipment  configuration  (I.e.,
electric pump at 200  ft  with the sparger  at  130 ft). Each air  flow rate
within a test  was called a  run.  Runs were  fifteen minutes long.   The
static water level was recorded before the start of each test.  Next, the
electric submersible punp was  turned  on and  the weir box  was allowed to
fill.  (See Section 6 for a discussion of the  weir box and  Its role In
water flow rate measurements).   A raw water sample was collected from the
electric submersible  pump at  the well head.  As  noted   In Figure  35,  no
small electric  sample punp was used,  as was  necessary for air  lift  punp
testing.   In  the electric  punp testing  (as  well as the air  lift  punp
testing) raw water  samples could not  be collected while  the  sparger was
In operation.   Because of this, the wel 1  had  to be cleared of  air between
each sample run so that a raw v/ater sample could be obtained for each air
flow rate  tested.   To clear  the well,  air  delivery to the  sparger was
stopped,  and   the  submersible  punp  continued   to  operate.    The  punp
effluent was monitored  for dissolved  oxygen  at the  raw  sample  location.

                                    84                          •

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-T.NJ. •
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M-

     f -" RAW WAT ฃR 6AMPLE
     P   LOCATION
                AT  ISO FT. ,200 FT.
                 OR..Z80FT,
ฐo
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00
 o
                                            -ELECT 1C 'PUMP
                                                AT  2OOFT-
                Figure 35.  Electric pump and sparger configuration vised for
                           testing at well L-8.                      .
                                               85

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a'
 When'the dissolved  oxygen of the water  being discharged'returned to  the
 concentration  at which  It was  before  aeration,  the well  was  declared
 -clear of air.  The  raw water sample was  collected, the next  air  flow rate
; for the sparger was started and the  fifteen minute run began.   Readings
 of all  of the  air  delIvery equipment,  water flow  rate,  and well  water
'level  were obtained  at  five  and  f1fteen ml nutes  Into each  run.   The
 treated sampled was collected  at the  fifteen minute point from  the  water
 discharging at the  y-notch of the weir box.   The water flow  rate used  for
 most of the electric pump testing was  100  gpm.  As with the  air  lift pump
 testing, the  limiting  factor for the  amount  of air which could  be  added
 through the  sparger was  water blowing  out  of the  borehole at   the well
 surface.  The water flow  rate was lowered  for later  testing, to  achieve a
 higher  air-to-water  ratio.   This effort  was only partly successful
 because the pumping water level was closer to the surface when less  water
 was pumped, so less air could be added  before  the  water came out of  the
'borehole.  /   .--    v  - •-• . :.-,•, "'•.'•  .'.'.•..'•-•..-'.'•;'!.;•'-•?•--•'-•.   --.-•'.."•  •••.•--..' '.'••"-  -.'• "•, •".:'•

 ELECTRIC PUMP TESTING WITH SPARGER - RESULTS  AND DISCUSSION    '

  .'•-.:' The VOC removal results for the electric pump testing with  a sparger
 are shown  In Table  16.   Three  contaminants (TCE, c-l,2-DCE,  and  VC) were
 used to evaluate these tests.  The maximum air-to-water ratio which  could
 be achieved before  water blew out of  the  borehole  was 8.2.  Maximum  VOC
 removals  were  82.6%,  79.9%,   and  92.9%  for  TCE, c-l,2-:DCE   and  VC,
 respectively.   These removals  were  better than those achieved by the  air
 lift pump  systems  at the same air-to-water  ratio.   The variabilities  of
 VOC removal were generally greater than air-to-water ratios at  the same
 rotometer settings,  Indicating that varying the depth of the sparger  did
 affect VOC removals.

     . -   TABLE  16.   VOC % REMOVALS BY ELECTRIC PUMP WITH SPARGER
                     (AVERAGE OF ALL 3  SPARGER DEPTHS)

: % REMOVALS OF VOCs
AIR
AVE
0.00
0.80
1.5
2.2
3.0
'3.7
;.4.5
; 5.2
•5.9
6.4
7.4
: 8.2
TO WATER
%RSD
0.00
0.00
0.00
9.2
0.0
0.0
4.4
3.6.
0.0
1.9
0.67
0.61
RATIO
N
6
3
2
5
2
2
6
5
4
3
2
2
TCE
AVE
14.7
18.5
32.9
49.8
53.7
62.0
68.4
72.9
70.5
77.3
79.4
82.6
c-l,2-DCE
%RSD
68.3
44.2
42.9
27.8
15.3
10.7
15.3
13.8
11.7
7.57
5.10
0.420
AVE
8.57
10.4
21.2
30.3
30.0
38.2
51.6
59.1 .
52.2
66.5
74.3
79.9
%RSD
97.0
33.6
65.6
55.9
43.7
26.2
26.4
19.7
18.5
15.1
3.90
0.500
VINYL
AVE
17.5
48.9
78.3
85.8
92.7
91.0
91.5
92.7
92.2
92.2
94.5
92.9
CHLORIDE
%RSD
60.3
8.13
9.45
6.00
1.29
4.23
5.00
1.92
3..3S
. 1.85
0.00
0.650

                                                   86


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t!;
,> - •": Figure 36 shows VOC removal results with theelectrlc  pump  at  200  ft
 and the sparger set at  130  ft,  200 ft or 280 ft.  The  results  Indicated
 that the best removal  was obtained with the sparger set  at  130 ft.   These
 findings were consistent with what could be expected In  terms of the well
 characterization discussed In Section 5.  It was determined  that most  of
 the VOC contamination was entering the well  In the two  zones between 106
 ft  and 1*ซ0  ft.   These zones  also  produced  nearly 60%  of the  water
 entering the well.  Very little water (less than 10% of  the well's  yield)
 was entering below  200  ft,  therefore, most of the water movement  In the
 well was  down  from 106-140  ft  toward  the pump  at 200  ft.  With the
 sparger at  130 ft, a counter-current stripper could have  been created
 with the air being delivered just at  the bottom of  the  most  contaminated
 zone.  This would be  an efficient way  to  strip the VOCs,  and  Figure  36
 shews the best TCE removal with the sparger at 130 ft.  When the sparger
 was  set  at 280  ft, this created  a co-current stripper  through a  very
 small portion  of  the  total  yield of  the well.   A good deal of the air
 could  have  been  pulled  Into  the   pump  before  It  reached  the  more
 contaminated water  entry zones.  When  the sparger  was adjacent to the
 pump at  200 ft perhaps  a portion of the  air was  pulled  Into  the  pump
 before any stripping could occur In the well.   In  an emergency  situation
 a well  characterization would not need to be done.   The  sparger  should  be
 placed above the  pump or below the  pump but these  tests  Indicated  that
 the sparger should not be placed directly next to  the pump.
      In order to look at the reproduclbi1ity of  electric punp and sparger
 treatment, the  test of the  sparger  at  130  ft  was  repeated  In October,
 1984, five months after the original test  at  130 ft.   The  results  were
 vastly different,  as  can be  seen In  Figure 37.   The  weir  box and air
 delivery systems were all recalibrated  to  determine If  any  air or water
 flow  rates  were  Incorrect.   No  Inconsistencies  were  found during the
 recalIbratlon.   The quality control  program for  sampling and  analysis v/as
 stir* !n place and gave no  Indication of any analytical  problem.   It was
 decided to do  two more  tests with the sparger at  130 ft,  two  days  In a
 row.  These  results for TCE  are shown  as  the January  23 and  24,  1985
 curves In Figure  37.  As can  be  seen In the graph,  the results of tests
 run two days In a row closely matched each other, they also matched the
 second  test  of  the  sparger at  130  ft,   conducted In  October,   1984.
 Because no  cause  for these  variations could be  found  In the  measuring
 procedures,   It  was determined that  variations  In VOC  removals for the
 same  In-well  aeration  configurations could have  been caused by  well
 changes over long periods  of time.   Conclusions based  on  the  curves  In
 Figure  36  are  considered  to be  valid  because  those  three tests  were
 performed within one month of each other.   It would  have been Impossible
 to determine exactly what was changing  In the well without repeating the
 well characterization Clogging and  packer testing)  described In Section
 5.   It was  known  that the raw water VOC concentration  and  static water
 level of the well  changed with time.  Perhaps  water entry zones  or VOC
 entry zones also changed with time.   Whatever caused the changes,  It was
 clear that  In-well  aeration, both with  the air  lift punp  and electric
 pump with  a sparger,  provided  variable results  over  a  long  period  of
 time at NPWA.  The same may be the case  In  other  locations,  depending  on
 the hydrogeology.
      It was difficult  to see any difference In vinyl  chloride removal for
                                                 87

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Ej
H
H
TO
aO
                       ao
                       to
                       3O -
                      100
ao -
so -
TO -
ao -
ao -
4O -
ao -
ao -
10 -
 o
                                                 . TOB ซ RBMOVAI-
                                •F-AROER 1SO FT
                                 apAROER aoo FT o/a*/a<ป —
                                 af*AROER aao FT. 10/3/0* —
                                                                                — D
                                                  O— 1.9— DOE X REMOVAL.
                                                  VO X REMOVAL.
                                                AIR TO WATER RATIO
                            Figure 36.  VOC removal by electric submersible pump and
                                        sparger combination, with sparger set at three
                                        different depths. Electric pump at 200 ft.

-------

         •'•rS-rr^
                    1OO
                     7O -

                     00-
                     30 -

                     ao-

                     10-ii
                    100
               a
               iv
                     oo -
                     ao -
                     ro -
 40

 SO

 2O

 1O

103

 BO

 •O

 7O

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 BO <

 4O

 SO

 ao •

 10

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                                             TOE a REMOVAL-
                                              -1.2—DOC SS MCMOVAU
*   a
                                            VC K R1CMOVAU
                        o            a            4            •            •
                                             Am^TO-WATtm RATIO
                         0 5/24/84  •    •"10/24/84'      * 1/23/85      Al/24/85
                         Figure 37.  Results of duplicate testing with electric
                                    submersible pump and sparger showing variation
                                    over five months time.  Electric pump-at 200 ft
                                    and sparger at 130  ft.
                                                89
X:
•:':- --x'

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                                                                                     ••*it
 the four repeat  tests  performed with the  sparger  at 130 ft Csee  Figure
-37). .As with the rest of the  In-well aeration tests, vinyl chloride was
 the most easily treated,  with the removal  curve rising very sharply,  then
.leveling out Into a plateau.                  .'••..         _ 'i   ' •;.--
      In Figure 37, the tests  conducted in January,  1985 were performed at
 60 gpm, while the two earlier tests use  a flow rate of 100  gpm.   While It
 was possible to  Increase the maximum air  to water  ratio  from 5.9 to  8.3,
 the amount of air which could be added was still limited by water  coming
 out of the borehole at the surface  of the well.  For all compounds,  with
 the exception of c-l,2-DCE,  It did not appear  that raising the air-to-
 water ratio beyond that achieved  In this  testing would cause any further
 removal.   This   Is  said because the  removal  curves have  reached  the
 plateau, which  Is normally seen In aeration curves, where adding  much
 larger amounts of air produces  very  little  further removal.    In  Figure
 37,  It  can be  seen that  c-l,2-DCE did  not reach  that plateau.   This
 compound has the lowest  Henry's  Law  constant  of  all  the   compounds
 examined.  If some way could  be found  to increase the air-to-water  ratio,
 more removal could be expected for this  compound.
      Costs for  the electric purp  and sparger combination  are  shown  In
 Figure 3?.   The  cost to  compress air  was calculated and 3$ per thousand
 gallons was  added as an estimated cost  for  electricity to operate  the
 punp.  As  with  previous  cost discussions, these numbers do not include
 operation and maintenance or  amortization of  capital  expenses.
  :    The most costly electric  punp and  sparger combination  tested  wฃ.-
 wlth the punp at  200  ft  and  the sparger at 280 ft.   The cost  approached
 15$ per  thousand gallons with  an  air to  water  ratio of 6 to  1.   Very
 little difference  In cost  could be seen  between the 130  ft  and  200  ft
 sparger depths.   The maximum cost  for  these depths was around 12ฃ  per
 thousand gallons.  The cost  of  this method,  together with the  ease  and
 rapidity of Installation, showed that electric pumping with sparging  was
 a viable emergency treatment  technique  for VOC  removal,  providing  the
 limited  removal   capabilities  would   meet  the   necessary   effluent
 concentration requirements.

 CONCLUSIONS FOR ELECTRIC  PUMP AND SPARGER TESTING

      VOC removal differences were  seen  when  the sparger was operated  at
 different depths relative to the electric  submersible pump which was  set
 at a depth of 200 ft.  The VOC  removal findings were consistent with the
 well characterization findings.   Sparging  at  130 ft provided the best  VOC
 removal.   This  depth  would  have  produced  a  counter-current   stripping
 effect as water  from the most contaminated  zone  in the  well  was  pulled
 down past  the sparger  on Its way to  the  purp.   With, the sparger  at  280
 ft,  a  co-current stripper  was  produced  as  both  bubbles   and  water
 travelled up  toward  the  purp with  some  or all of  the  air being  pulled
 into the purp before It reached the  most contaminated  zone.    When  the
 sparger was adjacent to the punp,  at  200  ft, most of the air was  likely
 to have been  pulled  directly  Into  the purp,  before any stripping could
 occur In the well.
      The maximum VOC  removals  obtained by  electric  purplng with a sparger
 were 82.6% for TCE,  79.9%  for c-l,2-DCE  and  92.9% for  VC, at  a maximum
.air-to-water ratio of 8.2:1.   These removals  were better  than for the  air


                                     90                       ••-•'..

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* SPARGER 130 FT 10/24/84 = D
t .'•'••.'
SPARGER 200 F 9/24/84 = +

SPARGER 280 FT 10/3/84 = ^


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                     AIR TO WATER RATIO
Figure 38.  Costs to operate electric pump and sparger for
            in-well aeration at well L-8.  Electric pump
            at 200 ft.                     .
                        91

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'<;:•'" 11ft  pump systems at the sane air-to-water ratio; however, a higher  air-
 /^^to-Water  ratio was  obtained with  the air  lift  pump (with  or without  a
 ''Ji.--:sparger)..      • ••'/-,-  •  ••,'.-    .       ......-     -. '  '.'.•.,.-  •--  ••••'•-'••;.•,.- . :.'". '-':.-.'
 \'.':'.;•••     The  electric purp with a sparger would be a good emergency treatment
;T  technique If Its limited VOC removal capabilities will meet the necessary
  .water quality goals.  It was  easy to  Install and Inexpensive to operate
    (up  to 15^  per thousand  gallons  for air  and electricity).   While  well
 ..". .characterization  was  helpful   for   experimental   design   and    data
  :  Interpretation,  It would not be necessary  In an emergency situation.   The
    sparger   should, not  be  set  directly  adjacent  to. the  pump.   In-well
  ;  aeration  by the electric submersible  pump.and sparger combination  can be
 ''', .used  to  keep a contaminated  well  In service while permanent treatment
   , systems are being designed and Installed.         ,:          ....     ;  .
                                         92

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                                                                                 **"
                                                                                 *ป
                                                                                1
                                                                               "• ฃ  *
                                                                                 ""~x
                                SECTION 11

                   SECONDARY EFFECTS OF IN-WELL AERATION
 GENERAL

      Part of the  scope  of this project was  to examine secondary effects      .   ...   _....
 of  In-well: aeration.    Dissolved  oxygen,   pH  and  temperature  were            ^  ;5
 determined  In order, to discuss corrosion Implications.  Bacteriological        .      -C?j
 tests were  conducted  using both the heterotrophlc plate count (HPC) and       •  :     *?
 the R2A plate count procedures.  In addition,  air samples were analyzed.        '  •  *,;
 at the well  head, at the weir  box,  and at the  sidewalk In front of the              "-?
 well  house.  These studies were not  the major  emphasis of this project       ,       •;•
.and they will be presented In a brief fashion.      .          •... "  . •     ... ~ ..'-?-'-•'.    v.

 DISSOLVED OXYGEN, pH AND TEMPERATURE        .,.        :      •   -;:  I .v"'.. :'"'-•'.'"{ y;  •'"••,vr|

      Dissolved  oxygen  concentration  and  pH  of  drinking  watซr  In the              ''•
.distribution system may  have  an  effect  oh  corrosion of  water mains.              ".!
 High  DO  and/or  low pH  can  cause  water  to  become  aggressive,  thus              :,:
 shortening the useful life of various piping materials.                                .'•;':
      Dissolved oxygen and pH samples were collected  In  BOD bottles at the
 raw water  sample  tap and  at  the v-notch  of  the  weir  box.   The samples            -   :,
 were analyzed  Inmediately In the  field for DO,  pH  and temperature.  DO       ....-.:•
 was measured using  an Orion Research Model  97-08 oxygen electrode.  The               :
 pH  and  temperature  were obtained  with a   Corning   Model  *t  portable              :
 pH/temperature meter.                                                    -
      The results of the pH, DO and temperature testing  are shown  In Table              •';
 17.  The mean values for all of the samplt-s  collected at the raw tap and              . ?
 weir  box  (treated)  have  been calculated.    The table  also shows the       i  "  ".'*
 standard deviation (SD), number of samples tested  (n),  and the %RSD.  The              ..--"
 range of values obtained throughout the testing  Is also shown.                .     '    •">
      In over  sixty  runs,  the  value  of  pH  was  found  to  Increase with       i     . '.-.'•
 In-well aeration  100% of the time.   The average raw water pH was 7.2 and       -      •".••
 the average treated water pH was 7.6, yielding an  average Increase of 0.4            -  ••'[
 pH units.   The  variation  In  pH was higher for the treated water (%RSD  =  .  .      '    Ji
 2.75) than for the raw water (%RSD =  1.62).   This Increased variation  In            ;: .^
 treated water  was  due  to  the fact  that these  numbers  represented pH              /
 values from the entire  range of air-to-water  ratios used during In-well              ^
 aeration  testing.   The  raw  water  could  be  expected  to  show  less            ...;••_]
 variability.  In  very general   terms,  an  Increase In  pH, as  seen here,        ;     |
 could help  prevent  corrosion In the  distribution system by pushing the              5
 Langelier Index to a more positive value.                                         -     .:;
      The average dissolved oxygen concentration for the  raw water was   .      ..       . :.'


  /--' .:''.-•..••         93          •.""-•.-.:' .-:'.•'  '".'.. .:"'..... ;"   :: •  ::=

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                                                     2^?^M;^^^^
                  TABLE 17.   SECONDARY WATER QUALITY EFFECTS OF IN-WELL AERATION
Raw
Treated
, Ave
7.2
7.2
SD
ฑ 0.12
ฑ 0.21
n.
63
65
%RSD
1.62
2.75
Range -:
7.0-7.5 ' - '.'•; -•--.'."".' '.
7.1-8.0 ; ' "..-;.
             Dissolved Oxygen-mg/L                     '
             Raw              2.17*1.15   78  53.0    0.9-7.5
             Treated         10.8  ฑ 0.52   78   4.78   9.9-13.0

             Temperature - ฐC     .        '•''".:"-.
             Raw             15.8  i 1.28   69   8.03   13.0-18.4
            .Treated   .   .   15.1  * 1.27   72   8.40   12.7-17.3

            . Bacterlologlcal-counts/ml
                           .  Method  Ave  SD  n  %RSD   Range
             Raw             HPC     73 * 61  21  84    2-243
             Treated         HPC     71 ฑ 79  21 110    1-282
                                       Ave % Saturation
                                            22%
                                           100%
             Raw
             Treated
R2A
R2A
638 ฑ 540 12
647 i 430 12
85
66
130-2100
 70-1370
             2.17 ppm over 78 runs.  The average dissolved oxygen concentration at the
             v-notch of  the  weir box was 10.78  ppm.   With average water temperatures
             of  15.8 and  15.1 at  the  raw and  weir sample  collection points,  the
             dissolved  oxygen  concentrations   obtained   represent  an  Increase  In
             dissolved oxygen  saturation from 22%  to 100%.  This increase In DO to
             100%  saturation occurred  for  the  entire range  of  ^lr-to-water  ratios
             tested.  No bubbles  were present In the  weir box by the  time  the water
             reached the v-notch.   Water that Is saturated with  dissolved  oxygen has
             the potential  to be more aggressive than a lower DO water.  This could be
             especially  harmful  In  systems with  unllned,   Iron pipe.   Since  the
             conclusions of this study show the  best  use  for  In-well  aeration  Is  on a
             short-term  basis  for emergencies.,  no  treatment  to  reduce oxygen  levels
             should be necessary.
                  The bacteriological testing during  In-well  aeration experiments was
             Inconclusive.   The results In Table 17 showed that both the heterotrophlc
             plate count and the R2A agar  plate count methods  revealed no difference
             In  bacteriological  quality  of  the  water  before  and  after  In-well
             aeration.  This was to be  expected,  because the  samples  were collected
             Immediately after  treatment, and any bacteria present would not have had
             time  to  be affected  by  the   changes  In  conditions.   This  should  be
             Investigated further  If the water enters a distribution  system where the
             bacteria have more time to contact the water with higher pH and dissolved
             oxygen at saturation.
                  The  bacteriological  testing did  show  a significant  difference In
             recovery  of  bacteria between the two  methods  used.    The  counts  of
             bacteria  per  mi 11II Her  were  approximately  9 times higher with the R2A
             method than for the HPC.
N
                                                 94

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 '.;'Further study Is needed to detennlne the effects of In-well  aeration       .-   :  •':
 on corrosion  and bacteria  In  a  water  distribution system.  Dissolved            ',
 oxygen  and   pH,   both  factors  which   can  Influence  corrosion   end        \   ,
 bacteriological  growth, are  clearly  affected by In-well  aeration.     -         .•/  . "

 AIR SAMPLING      . ',    '>;'     '      .  •-;:  '. . / ;. ;- -'"'. '- '• •  .">"''.. .;  "•":. ':'~. ' "'',;_'•. J''^' /'%

•.-•'•.  Air samples  were collected  during  four  In-well  aeration  tests  to        - — ,.:
 determine possible exposure hazards In  the  area around the well  house.
One method- used  was  an adaptation  of  GC  purge and  trap  techniques           "
 C35,36)..  A  second  survey  was done  using  a portable photoIonIzatIon     .        •
 detector.  The air tests were  Intended  to  be a preliminary estimate  of
 air concentrations  to  determine whether further consideration of  air      .   ;
 "exposure would be necessary.                     . .             ..-     .     ,   . -       ',-'.

 Trap and Pesorb Method - Results and Discussion          -'...'        .    . ;   ;.    :

      Volatile organic  chemical  traps from the GC purge arid trap sample
 concentrator were  used to  collect  air  samples.   The traps were packed          •'•.-
 with Tenax,  silica gel  and  charcoal.   To clean the traps  In preparation
 for  testing,  they  were baked for  one  hour  In the  purge  and  trap
 apparatus.   After  the  bake cycle  they  were  desorbed   Into  the GC  for
 analysis to confirm  that no organlcs  were remaining on the trap.   Once
 cooled, the traps  were removed from  the purge  and  trap device  and  the
 ends were  Itimedlately  sealed  with  parafln  film.  One  sealed  trap  was
 carried Into the field and returned  to the lab without breaking the seal,
 to act as a field blank.
      The configuration of the air sampling system Is  shown  In  Figure 39.
 Two of the laboratory  prepared  traps wore hooked together with fittings.
 This assembly was  performed In the field immediately before  the sample
 was collected.   Two  traps  were used  In series  In order  to provide  a
 primary analytical trap and back-up trap to  test  for  breakthrough of the
 primary trap.
      The traps  were  connected  to an  Industrial  hygiene sampling  pump.
 The outlet of the  pump was  directed Into a  bubble flow  mettr  to measure
 the air flow.   This was necessary because earlier laboratory tests showed
 that each combination of traps produced a si Ightly different flow  rate
 for one particular setting on the sample  pump.                                    .
      The system was  calibrated by  purging  an aqueous standard  onto  the
 Tenax/slllca gel/charcoal trap and desorblng as for a regular GC  analysis
 of water,  however,   Instead  of calculating  as ug/L  of  compound  in  the
 aqueous sample,  the GC was calibrated to  the actual nanograms of  material
 adsorbed by the trap.   When the traps from  the  field were  desorbed,  the
 results were reported In nanograms.   The  field measured air flow rates of
 sample collection  were  then  used to  calculate  aJr  concentrations.   An
 example calculation to  determine volatile organic chemical  concentration
 1n .aIr Is shown be1ow:                                                       ,    '  • ..
      1.  Determine cubic meters of air collected from field flow                        1
           data which is measured In  liters/minute.                                      I

-   .;'   -.'-.••.             '•  '       •            '      ;"•-.-,••    .';•:.  I


'   J'         ..  - -           '        95              '           '          ."••'•-.'••-/'•.!

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m
w
                              BUBBLE
                               FLOW
                               METER
                                                   SAMPLE PUMP
                   Figure 39.  Drawing of air sampling system vised to test off-gases
                              of in-well aeration.
                                               96
                     ^^&^li^aliSl^^ฃ^^

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           collection time (mln) x flow rate (L/mln) = Liters air
           sampled
           Liters air sampled = cubic meters of air sampled
           1,000 L/m3
      2.  Determine mlcrogram/cubic meter concentration In air.

  ..         ng VOC col 1 ected / cubic meters of air sampled =   .  .    ."-;''  •
  ; .   'V   1,000 ng/mlcrogram    mlcrograms VOC/cublc meter air
;;.  :  3.  Convert to parts per billion VOC In air              . .      ,1   '.

  .    --•.."• ppm- (0.02445 cubic meters air/mole air) x                .;/•>'
     .            (x ug/cublc meter VOC In air)                        .
     •:'•;.;         molecule weight of VOC, g/mole
      V   ppb = ppm x 1,000       ••.;..:  ._.:.-.-,',.     '   :.      •.   ;

..:'•    Sampling  locations  are diagramed  In Figure  40.   For  this  method,
.'sampl es were collected directly at the well head, above the treated water.
 sample  location  of the  weir box  and at  the sidewalk  In  front of the
 pumphouse.  The samples were collected  while  operating the  electric pump
 at 200 ft  In  the well  and with the  sparger delivering  the  maxlnnum
 possible air at 130 ft.
      The results of the air sampling  by trap  and desorb method are shown
 In Table  18.   In  both samplings, concentrations  were very high at the
 well  head, lower at the weir box and nearly zero at the sidewalk In front
 of the pumphouse.  There were several problems  with the method.   Each of
 the  back-up traps  showed some contamination. (1% to 5% of the main  trap
 concentrations) by the  major  compounds.   In the  second sampling,  the
 field blank was contaminated  (see Table 18).  Even  with these problems,
 It can be seen  that  the  VOC  concentrations  In air  may be  reason for
 concern, and  would require further  study by a  standard method  for air
 analysis.  The  Pennsylvania Interim Air Standards (37) for TCE  and PCE
 are  1200  ppb.   The well  head sampling  exceeds  or nears  these  limits In
 both cases.  The VC Interim limit is 2.4 ppb, 1,1-DCE is 37 ppb and CCL4
 Is 12 ppb.  All of these are exceeded at the well head by this method of

        TABLE 18.  RESULTS OF AIR SAMPLING BY TRAP AND DESORB METHOD

FIRST SAMPLE COLLECTION

Air Flow
Col lection Time
VC (ppb air)
1,1-DCE "
c-l,2-DCE "
'CHCL3 "
11,1,1-TCA "
•CCL4 "
TCE "
PCE "
Well Head
21.70 mL/mln
30 min
810
200
GT3,600
0
120
14
GT4, 200
GT1,900
Weir Box
15.06 mL/mln
30 mln
0
5.3
55
0 ' .
5.3
0
130
13
Sidewalk
19.40 mL/mln
30 mln
0
0
0
0
0
0
• 1.0
i 0
Blank
no al r
sampled
0
0
0
0
0
0
0
0
i(continued)
                                     97
                                                            fe^&a^^

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SECOND SAMPLE COLLECTION
. '•*• v. , . Well Head
Air Flow
Collection Time
VC (ppb air)
1> 1-DCE " .
C-1,2-DCE "
CHCL3 H
1,1,1-TCA "
cent •'"•.:
TCE "
PCE "
20.02 mL/mln
15 mln
21
1,900
" - - 0
160
•'-••• 35 .
GTS, 700
700
Weir Box
15.62 mL/mln
15 mln
2.7
0
11
0
7.5
0
.57
Sidewalk
19.36 mL/mln
15 mln
0
0
3.3 •.;
. o ../:
0
0 •-.''.
8.2
1.0
• ':'•-.• -.:>' .
Blank
no air
sampled
:.. 0
10
0
1.5
0
12
0

           ,GT = Greater Than                •                .                   .    '•-'•
            0  = Less than  1.0 ppb  In air                            ."'';  ,      -"'••'":

            sampling  and analysis.   Air  discharge permits  and/or air  VOC control
            measures  might  be needed for wells as heavily contaminated as this one.

            PhotoIonIzatIon Detector Method - Results and Discussion

            .'•-'- Another  type  of air survey was completed using an HNU Model P1101
            PhotoIonIzatIon Analyzer.   This  Is  a  portable  Instrument which samples
            air  and  Instantaneously  reads  total  VOC  concentration  In parts  per
            million as benzene.   The air was tested at the well head, above the weir
            box and at the  sidewalk  In front of  the well house, Just as with the trap
            end  desorb method.   In addition,  the  air  was tested  two feet directly
            above the well  head  and at a workbench In the well house approximately 8
            ft from the well  head.   The  latter two locations were selected to see  If
            workers who were In the well house  would be  exposed  to dangerous levels
            of VOCs In the  air.
                The  HNU  analyzer survey vies done  while operating  the air lift pump
            at  200  ft with the  sparger  at 200 ft.  Air was tested with the sparger
            off, then with  the sparger blowing  the maximum  amount  of  air C50 cfpm).
            The  results  show no response  on  the analyzer  at  any  of  the  sample
            locations when  the  sparger was not operating.  The lower detection limit
            of  the  Instrument  Is 0.2 ppm as  benzene.   With  the  sparger operating,
            there was no  response at  the work  bench,  weir box or the sidewalk sample
            sites.  The weir head gave a response of 6.2 ppm and the sample two feet
            directly  above  the  well  showed a  response of  1.8 ppm.   Since workers
            would generally not  be  In the  Immediate  vicinity of  the  well  head for
            long periods of time, the operation  of  this In-well aeration system would
            not pose  a hazard  to workers.  In spite of these results, however, It  Is
            reccmnended the.t the well  house  be well ventilated when using an-In-well
            diffused  aeracor to  avoid build-up of the VOCs In the air.  These samples
            were  collected  with well  house  windows  and  doors  closed  to  try  to
            simulate  a "worst-case" situation.
                                                98
'^N '




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I
                                      :rffi
                                      WELL HEAD
                                          WORK
                                         BENCH
                                                               WEIR BOX
                                                                V-NOTCH
                                                      6IPEW
ALK
                                  3rd    STREET
              Figure 40.      Air sampling locations for in-well aeration
                            off-gas testing at well L-8.

                                :          99       '.'••'.•
 &***&.
                                                                                 -\

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$••• •_'
f'
fc i
:^ '.;-:'' All, methcxls of: In-well  aeration tested  Increase the pH  of the well
"water by  an average  of O.1*. pH units.  .Dissolved oxygen  was  raised  to
/saturation by  all  of  the In-well  aeration methods  tested.  The  oxygen
  Increase  could  cause  water . treated  by  this  method  to  become  more
  corrosive.   This  should  not be  a  problem  for  short-term use   In  an
, .emergency situation.               ",..-.:••           .    . .'••  '-. -•• .•'•'••••;  :; , :
   •  'Water  entering  the  weir  box  after  sparging  was milky  white  In
  appearance.  By the  time  It left the separator It was  clear, causing  no
 'problems with aesthetics.       .   •'.  ,_   .  ;•..•":.   • .•:'     ':  .-•  ••'•':
   V; :  The   bacteriological   testing   of  raw  and   treated  water  was
  Inconclusive,  with  large variations  In  bacterial  counts masking  any
  trends.    The  R2A method  provided  consistently   higher   recovery  of
; organisms than the heterotrophlc plate  count.                        . .
       Air sampling  showed that In-well  aeration would probably  not cause
  air quality problems of  Industrial hygiene  concern, however, the well may
  be  considered an air  pollution source,  and would  require  any  appropriate
  permits  for  such  a  source.   This   would   depend   on  the  raw  water
  concentrations of the contaminants  and  on air flow rates  used.   It would
  be  prudent to ventilate  a well  house with an  In-well diffused aerator In
 'operation.'       -   •••-.-••   .; . . -    '   •  : -::.;-- • ;. -."-••".' .'}.-.,,•"•      '"..-.'..  '
                                                  100
                                        0eu&ir^^

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                              , SECTION 12

                             COST ESTIMATES
FIRST SCENARIO                ;         .  ;     ..'."-.•        •        .     :

     In  this case,  costs  have been  computed for  an  In-well  aeration
system to be used at a well with an  electric submersible pump In place.
The well  is  500  ft deep with a  static water level  of 25 ft and a pumping
water level  of 100 ft.  The water flow rate Is 70 gpm.  A sparger will be
added  to  the well   for use  with  the existing  submersible  pump.   The
sparger  will be  set  at 175 ft.  The pump v;Ill  remain at  200  ft.   The
system will  be In service for approximately three months.
     The VOC concentrations are 10 ug/L of TCE and 250 ug/L of 1,1,1-TCA.
It would require 50%  removal  for TCE  and  20% removal  for  1,1,1-TCA to.
bring the VOC concentrations below the limits.   In-well  aeration would
produce the  necessary  removals.                .
     Cost to rent air compressor (3 months)
     1  In PVC plpe/flttlngs/valves
     Fuel tank (250 gals)
     Air filter
     Well vent
     Installation labor

    Operating Costs -
     Oil and Filters
     Gasoline (2 gal/hr)
     Labor
     Electricity (3^/1000 gal/wtr ptnped)

    Electric Pimp and Sparger
     Total Cost-3 months operation
    Cost per 1,000 gallons of water treated

SECOM) SCENARIO
$ M92
    200
    500
    175
 .   300
  2,000
$ 7,267

$   500
  4,368
  5,460
    281
$10,609

$17,876
$ 1.91
    'In  this case vie desire to  bring  an old well  back  Into  service.
There  Is no  punp presently In the well.  The well  Is  300  ft deep with a
static water level  of 45  ft and a  pumping water  level  of 70  ft.   The
water  flow  rate Is  70  gpm.   An  air  lift  purp  and  sparger  will  be
Installed.   The  air  lift purp footplece will be  at 200 ft  to yield 65%
submergence.   The sparger will  be  at  250 ft.   The  system will be  in
operation for three months.
                                    101

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   :  •.>-..':  ./'•.'•   .'The well has  a TCฃ concentration  of 20 ug/L  Cneed  75% removal), a
           ,;-.;    PCE concentration of  5 ug/L and a VC concentration of 5 ug/L Cneed  80%
    -.'.-•/•"''-••'•'":.•• removal).'  The air  lift pump and sparger, combination should provide  the
        .-.','•••    necessary VOC removals.            .           .,.-.'.•  ;;   :    •.. ;•.'••.--•-''.'• '-;••/>..:• •• •.•-.•
                  •    Cost to rent air compressor           ,  $ 4,092
/     '•.:."•".            _2i In steel pipe Ceductor)                :  390
                      Purp footplece Cmaterlal 6 fabrication)     200
     ...        .  . ;Alr line Cl In) forpump              .     150
     -'."•-"    .   '     1 In sparger pipe                      .    ,250
       "   .   .      .   Fuel tank C250 gal)         -         •/"     500
           :',.'••  ;      Air filters     .  •               "..-'--. 175.
      .-        .    ^  Well vent                              .    300
                 .    .Crane rental Cto Install punp eductor)      500
       •••   .        :    Installation labor                        3,000
                  /';.'••'     -         '                         $ 9,557
     -      "          Operating Costs -
       <               Oil and filters                         $   500'
                      Gasoline C2 ga^./hr)                       4,368
                      Labor   .   '  .    .            ;      .       5,^60
                                           '      '          -   $10,328
                     Air Lift and Sparger -
                      Total cost - 3 months operation         $19,885
                      Cost per 1,000 gallons of water treated $ 2.12

                 GAS AND WATER SEPARATOR              '     • —  ;     .
                      If  the  well  being  treated  does  not  have  a  previously existing
                 chlorine retention tank,  one will have to be Installed  to  serve as the
                 gas and  water  separator.   Costs  shown  here do not  reflect  the costs of
                 additional  chlorine,  which might be necessary because of,  stripping as the
                 bubbles are released.                         •

                           Concrete tank (1,500 gal)      $ 2,000
                           Punp Cto system)                 1,000
                           Electrical  control equipment     1,500          .
                           Installation                     2,000
                            .   -                          $ 6,500

                 DISCUSSION                                           .                   .

                      The total cost  of an electric  submersible  pump with a sparger was
                 less  than  an  air   lift  punp  and  sparger,  as  long as   the electric
                 submersible punp was previously  In the well.   These costs  did not show
                 purchase or rental  of an electric submersible punp.
                      In-well  aeration may not be a good treatment  option If a gas-water
                 separator  Is   not  already  present.   A  chlorine  retention tank  would
                 probably be Included  In  the construction of  the  permanent  VOC treatment
                 facility.  The time Involved In Installing the tank would probably negate
                 Its usefulness as an emergency treatment measure.
                                                     102

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X
                                           REFERENCES

                 Woodhall, Richard S., "Groundwater  Contamination In Connecticut",
                 AWWA Annual Conference Proceedings, Atlanta,  GA,  1980.

                 Massachusetts, Ccmnonweal th of, "Chemical  Contamination";  Dept.  of
            .  :V Environmental Quality Engineering,  Working Paper for the Water
           .   ".  Quality Task Force of the Special Legislative Ccrmlssion On Water
           .;••;    Supply, September 1979.             v       :  ?     ^  .      .   ,i3 :.

             3. , Cl Ine, Gary C., Thomas J. Lane, and Mario  Saldamando, "Packed      :
                 Column Aeration for Trlchloroethylene  Removal  at Scottsdale,       .
           "v• 'o.  Arizona", AWWA Annual Conference Proceedings,  Washington,  D.C.,
           ••;'.•.;-,. 1985.;.._ • _ :-,.;,. ;•.... -'  • r .;  ' . : :\^.,-;   \: ,_:. ^ . ^.-:f, •• ^-,' C- ^

             4^  Cumnlns, Michael D., "Removal of Etyhlene  Dlbromlde CEDB)  from
           '-'•-'•    Contaminated Groundwater by Packed  Colum  Air Stripping",  U.S.
           :" ;EPA Off Ice of Drinking Water Report, August 198
-------
 f.  :  •   -  '1  11.  Suffet; I.H. (Mel), Jacob Gibs, Judith A.  Coyle,  Robert S.  Chrobak,:
 H '  .:.   : •-. ••'•-.- ."and Thomas L. Yohe, JAWWA, Vol. 77, No.  1,  1985,  pp.  65-72.        V;

 .  '   •''.'.-• '"•  •-.  12.  Coyle, Judith A., Harry J. Borchers,  Jr.,  and Richard J. Mlltner,
 '•        . ."•'-..   .:-  "Control of Volatile Organic Chemicals  In  Groundwater By In-Well
 •':                 :  Aeration", AWWA Annual Conference  Proceed I ngs,  Washington,  D.C.,
 ; '/•—'         ••'",  1985, pp. 1101-1114.            . ,.    '.      .-.,..   .  ;;-:\  -; "'••?: ..;

 :"'•'.       13.  Rlma, D.R., "Groundwater Resources of the  Lansdale Area,
 '-;•-.           ...  Pennsylvania", Comnonwealth of Pennsylvania,  Dept. of Internal
                   .Affairs, Topography and Geologic Survey, Progress Report No. 146,
 (  '•'  -     '  ';      1955.  •           .••--•  ..,.-.;..•.     ..     '    •-; /•:•• .    , .'.

               14.  Longwlll, S.M. and C.R. Wood, "Groundwater Resources  of the    .
             '-..-    Brunswick Formation In Montgomery  and Bucks Counties, Pennsylvania",
          -      .'•-.•• Comnonwealth of Pennsylvania, Dept. of  Internal Affairs, Bureau of
 :    .              'Topography and Geological Survey,  No. 7, 1965.            ,   - .

 „              15.  Itorth Perm Water Authority, Well L-8  Permanent File,  Driller's
 ;'•'.'   .  ..,-         Report, 1923.               .                     ^..-;.  -          .-'•.'

               16.  Federal Register, 40CFR141, Vol. 50,  No. 219, 11/13/85, p.  46880.

 /          .    17.  Wright, R.E. Associates, Inc., "Special Groundwater Study of the
                    Middle Delaware River Basin, Study Area  II",  Vol. 2,  Delaware River
                    Comnlsslon, Trenton, N.J., 1982.

 •              18.  Johnson, A.I., "Geophysical Logging of Boreholes  for  Hydrologlc
                    Studies", U.S. Geological Survey Open File Report, Hydrologlc
                    Laboratories, Denver, CO, 1963.

               19.  Keys, W.S., "Borehole Geophysics as Applied to Groundwater'',
                    Geological Survey of Canada, Economic Geology Report  No. 26, 1967.

 :              20.  Papadopulls, S.S., J.D. Bredenhoeft,  and H.H. Cooper, Jr.,  "On  The
 :                   Analysis of Slug Test Data", Water Resource Research, Vol.  9, No. 4,
. /  !. -  ',-    . .-•''-.  1972.  •            -           •             ••.'....:.-

 ;"•'•.     21.  Moorshead, Tucker, "Hydrogeologlcal  Investigation of  Well L-8,
                    Lansdale, PA", Project Report to NPWA, Earth  Data, Inc., St.
 -                   Michaels, MD, 1983.

               22.  Shuter, E. and R.R. Pemberton, Inflatable  Straddle Packers  and
 1  "           •     Associated Equipment for Hydraulic Fracturing and Hydrol.oglc
                    Testing, U.S.G.S. Water Resources  Investigation 78-55,  1978.

  '',',           23.  Cherry, R.M., "A Portable Sampler  for Collecting  Water Samples
                    from Specific Zones In Unusual or  Screened Wells", Geological
                    Survey Research, (U.S.G.S. Professional Paper 522), 1966.
                                                   104


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37.: Pennsylvania Interim Operating Guidance For Air Toxic  Substances:
--^.' New and Modified Sources,  l27.12CaX2>:9, Revised  9-27-85.
                                                                   j-
38.* Kent, Robert T., edi> Kent's Mechanical Engineers' Handbook,
     El eventh Ed 111 on, John Wl1 ey g Son, New York,  1948.

-39." Seelye, Design, Vol. 1, 2nd ed., John Wiley S  Sons, NY,  1953.
                                                                                       *J   —_

                                   105

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                                                APPENDIX A

                                         SUWARY OF EQUATIONS USED
fe:
                1.   AIR' DELIVERY  -  Equation  used  to  adjust  for  differences  from
                calibration temperature  and  pressure for  air  rotometers  (supplied  by
                Brooks Instrument Company):                               . . ..'...:       .
                               rotometers
      Qact   = Q
                              !Pcal
   .   Where - Qact   = Air Discharge,  SCFH    ...
      .  -,    Qroto = Rotcmeter Reading               "•'.'
     "     •-  Pread = Pressure at Rotometer + lk.7  psl (absolute!)
••''•>;   :.  ,;':, Peal   = 75 psl  + 14.7 psl = 89.7 psl
        '.•    .Tread = ฐF Air  at Rotcmeter + H60ฐF            '•  /.'.'
'.;• -."•:''.--.-    Teal   = 70ฐF + A60ฐF =  530ฐF    .       .'.'       .  '\ ,   .'

 2.   SUBMERGENCE -  percent of air lift  pimp eductor which was below  the
 pumping water  level  (reference 29}:              '-..-.••
                             S = L - h x 100
                 	           Where - S = % Submergence
                    L'  L = Distance from footplece
               .'".•    .                         to discharge pipe
                                    '-.  .   h = Distance from pumping
               •  .                             water level  to discharge
                                              pipe

 3.   V/IRE-TO-WATER  EFFICIENCY - derived fran water horsepower and required
 compressor horsepower  (reference 38):
              HP   =0
                w    -*w
                                          h x 8.3U5 Ib/qal .= 0  . h
                                           33,000             39^5
              Where -  HP   = Water Horsepower
                       0 w  = Water Flow Rate (gpm)
                       h    = Distance from pumping water level
                        •      discharge pjpe
                                                                               to
                         x 0.01511 x P.
                                                               29  -
              Where -  HP   = Adlabatlc A!r'HorsepOwer
                       PI   = Absolute Pressure of Free Air
                     " P9   = Absolute Pressure of Air Supplied to
                       Q7   = SCFM Air Supplied to Pump
                                                    106
                                                                                  Pump

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                                    •;.:'•-.,. :" •'-.v.'i:":-'"---i-t'' Horsepower-for. Electric "/"• ,;.'"ป\ r-"C5'..-ฃ-ฃ>'f
                                    .',, /.V-Vip'' ^~';'-).:'.-V'G Motor'  ""'.-•.:>~.^^-;~~~^^J,'";:-lf^:'^ฃ^fฃ^:^
                                    '-',^-••; - - c.*V •/•'•.-' ^^ -."' -=- 'Compressor Ef f I c I ertcy ;:.' [i-;':' ^'.^^''^-''^
                                    A.-':;'1 - /XX'* E   ;=' Motor Efficiency - '•-.-'-.  V-v-e:V ^&^;^t:'Z&
                                                            Efficiency.
                                  r?'-1?--."--"-'1'^ "'-••'."'' '"-.'.•'"•••. "•.:.-.;'/>" ;'.'/-'-vv';--V-'v?S<:;,^''U,r' •;-^';,;--'?-rni-':-:v.: s ;'^
                       	         .   Where - E   = Estimated WIre-to^ater: : .  -,. ' :-; "0  i'';|
:;;:,: :',\;;•••-<;-,- ^:ฃ*';-w%['-":'••   •  •.:•'•.-:"-'"..'.'-'.-v.-.V Efficiency;  ^.^^^//:-:-4i->^';^j^^^
 :':--''V ;   "'';'f'-;- --'-^V. :":-^" .:"i  :'•••'.':'.'.'• "••••  -•.'"". HP."'='Water .Horsepower ''.    '..{"_"/'''/ :":%••".'i^'^jj
;•.,•.'•;.'.;;.• -'-'-'^i  -•;.;.  ["il"-:";':.;--'•'••'•vX:',.''V.'•••"•'.•;   '  ;  .Hpc = Required Compressor  . v'•.';-;.^-':l^^"^>-ป^;'-|
:/',,-.":;•;;-' -i-:-VT%^:./;.> 7 ^.'.:/^v:v ;-';.;/,;'-   -,- ; •>•:>. ..  ^Horsepower   -/ •'.;;• '""/• vV^->;-C-5:--:Sv^^_;|

 U. .- ATR-TO-WATFR RATIO-  •"   :;  ' ' '"':-" ' '' " '" .":'. -"'"?; {'.••^:/iT/^-S ;:-'"^\^^^>^^ฎ:?^^i;.^i'^
               -E .  ..  =  HP
 ,-:• -j    'H  -;V- =
•   ,v.: /;;;=:'.:  V*"  "; .
    "
                               x 7.^8 gal/ft3
                              gal/mln
                                  '    '
-,'^.:-/'-  ;t:;  r -  Where -r V. = Vo1uiป of Air   •'--.  '^;^''-: V-:'r:;. -:^ V'iv^;
J'-.^::-'--^":--:-:^ •'":••'-•,.^:- Voluns of Water  '  ; •- '.-";>-;"/'-: 1: ^,:'" ^V^v-'-:^
•'  '"*--• •'' '"'•.'.-.•'""'•:'...';' .'<••-••'- • W'.'.:••'      ,• • ..:• -' ,./•-.• ...'.•'.•:.  ^  . _ "'•'..-•.-•/•'X ' -. '•:"..'",'"' '• -\.-''• .'-".'<'t.

:5.; WATER  LEVEL MEASUREMENT USING AN AIR  LINE -  feet of water' In  the air
  line Is  calculated from the  pressure  required to  remove the  water from
ithe  line,  then substracted  from the length of  the air  line:              .   -
               • L   =   FV/
                 w
                        0.^335
                WL = LA,  - L
                      AL    w
                                      Where -  L   = Feet of water In air  line
                                               PW  = Pressure required to  move
                                                     water out of air line
                                               WL  = Water Level
                                             L.,   = Length of Air Line
                                         '
 6.  .WATER FLOW RATE  - as calculated from a 90ฐ  triangular v-notch weir
 (reference  39):                                  .   .
 :  /;.    ,    Q>cH5/2


 7.   %  REMOVAL OF VOC =
               C^ - C,. x  100%
                                      Where  -  Q  = Water Flow Rate CftVsec)
                                                H  = Height of Water Above Weir
                                                     (ft)
                                                c  = ^86.2 for weir box  used
                                      Where  -  CR =  Raw water concentration
                   Cp                           CT = Treated water concentration
                    K                            I ' .            .   -  - .     ^.

 8.   COST TO  COMPRESS AIR - calculated at 6* per  kilowatt  hour

                Cost.t/1000' gal =  6<=/KWHr  x 0,7*t6 KW/HP x HP  x 1,000  gal
                                                 x 60 mln/hr
                                              w

                Where - HP  = water horsepower
                        0.   = water flow  rate (gal/mln)
                                        107
                                                                w

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                                          APPENDIX B

                              GAS CHROMATOGRAPHIC COUDITIONS Ahฉ
                                    QUALITY CONTROL PROGRAM
           ; .   All yo.latlle organic analyses were performed using EPA Method  502.1
          for the gas chromatograph (GC).   The analyses were done at  the  North Penn
          Water Authority Laboratory using a Varlan 4600 GC with a Varlan Vista 401
          Chromatography Data System.  The samples were concentrated  and  Introduced
          Into the  GC by way  of a  Tekmar LSC-2  Purge and Trap equipped with  a
          Tekmar ALSAutosampler.  The  trap was packed with Tenax,  silica gel  and
          charcoal.
               The  GC  colum used  was 8-foot,  glass, 1%  SP-1000  on Carbopack-B
          (60/80 mesh).  The purge and carrier gases vrerc helium. The detector was
          a  Hall  Electrolytic  Conductivity  Detector  (HECD).   The  temperature
          program sequence was  45ฐC Isothermal for  three  minutes,  program at  8ฐC
          per minute to 220ฐC>  then hold at 220ฐC for five minutes.
               The NPWA Laboratory Is certified by the Comronwealth of Pennsylvania
          to perform  trlhalomethane analyses  under the Safe  Drinking  Water  Act.
          Method 502.1  is used  for the  ThM  as  well  as  the VOC  analyses.   The
          quality  control   program  used  with this  method  Is  approved  by  the
          Carmonwealth  and  has undergone  In-house  Inspection  of record  keeping,
          equipment, analysts and procedures.
               In addition  to  the  Safe Drinking Water Act requirements,  several
          quality control  procedures were developed  specifically for this  study.
          Once every three months, quality control  samples were  obtained from U.S.
          EPA-EMSL  for  volatile  organic chemicals.   The  samples were provided, at
          two  levels  of concentrations,  and  had  nine compounds  In each sample.
          Every  day one of  these samples  was analyzed,  with  high or  low  range
          concentrations being examined on alternate days.  The results for  each
          day were compared to the true values provided by U.S.  EPA-EMSL  before any
          samples were  analyzed.    If  error  was  less  than  10%,   samples  were
          analyzed.   If  the error was  greater than  10%,  the cause of  error  was
          determined and corrected before  samples were analyzed.
               All  VOC samples were collected  In duplicate  In the field.  At  least
          10% of these field duplicates were analyzed.  The percent  difference for
          each  compound was  determined  by dividing  the difference  between  the
          duplicates by  the average of the duplicates, then multiplying  by  100.
          The percent differences were  wel 1  within 20% for the  compounds found In
          well  L-8  at  high concentrations,  and within  25%  to  30%  for  the  minor
          contaminants.            .                      .
               In order to determine the  GC retention time stability, and thus be
          more confident In the VOC  identifications,  the retention times for  each
          compound  In  the-.dally  calibration standard  were"  recorded.   These  data

                                     •-•••-.      108
"^

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        -.->!•       ป                                           s-^ir*.      f 'A.    J
     —-.'  ป    .A.    ,  *  t  "          -**1"            -^       *,*/',.V*>t      *"*      *  "*3^-
        t     •{<•''        ป.   i   '     *                   *      J-         i- ~ -  ป~  *  ^ ^ ,2   *
    'f4 ,•• ""were compiled on a  monthly basis  and the  average,  standard deviation,         ' "  ;'
      t~ - '^percent  relative  standard  deviation  and  retention  time  relative  to:         "  "'
         ซ   chloroform were  calculated  for each compound  In the method.:  Percent          •**
            relatlye ;st'andard deviations  were  generally  less  than  0.5%.   ' If the   -          ^^
          ^average.retention time changed from the previous month, the new retention
       • ' *  time was Inserted Into the GC method  In the  data system.                    -,*
X
 \
                                               109
                                                                                                     \

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